/*- * SPDX-License-Identifier: BSD-2-Clause * * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. * Copyright 2003 Alexander Kabaev . * Copyright 2009-2013 Konstantin Belousov . * Copyright 2012 John Marino . * Copyright 2014-2017 The FreeBSD Foundation * All rights reserved. * * Portions of this software were developed by Konstantin Belousov * under sponsorship from the FreeBSD Foundation. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /* * Dynamic linker for ELF. * * John Polstra . */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "debug.h" #include "libmap.h" #include "notes.h" #include "rtld.h" #include "rtld_libc.h" #include "rtld_malloc.h" #include "rtld_paths.h" #include "rtld_printf.h" #include "rtld_tls.h" #include "rtld_utrace.h" /* Types. */ typedef void (*func_ptr_type)(void); typedef void *(*path_enum_proc)(const char *path, size_t len, void *arg); /* Variables that cannot be static: */ extern struct r_debug r_debug; /* For GDB */ extern int _thread_autoinit_dummy_decl; extern void (*__cleanup)(void); struct dlerror_save { int seen; char *msg; }; struct tcb_list_entry { TAILQ_ENTRY(tcb_list_entry) next; }; /* * Function declarations. */ static bool allocate_tls_offset_common(size_t *offp, size_t tlssize, size_t tlsalign, size_t tlspoffset); static const char *basename(const char *); static void digest_dynamic1(Obj_Entry *, int, const Elf_Dyn **, const Elf_Dyn **, const Elf_Dyn **); static bool digest_dynamic2(Obj_Entry *, const Elf_Dyn *, const Elf_Dyn *, const Elf_Dyn *); static bool digest_dynamic(Obj_Entry *, int); static Obj_Entry *digest_phdr(const Elf_Phdr *, int, caddr_t, const char *); static void distribute_static_tls(Objlist *); static Obj_Entry *dlcheck(void *); static int dlclose_locked(void *, RtldLockState *); static Obj_Entry *dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, int mode, RtldLockState *lockstate); static Obj_Entry *do_load_object(int, const char *, char *, struct stat *, int); static int do_search_info(const Obj_Entry *obj, int, struct dl_serinfo *); static bool donelist_check(DoneList *, const Obj_Entry *); static void dump_auxv(Elf_Auxinfo **aux_info); static void errmsg_restore(struct dlerror_save *); static struct dlerror_save *errmsg_save(void); static void *fill_search_info(const char *, size_t, void *); static char *find_library(const char *, const Obj_Entry *, int *); static const char *gethints(bool); static void hold_object(Obj_Entry *); static void unhold_object(Obj_Entry *); static void init_dag(Obj_Entry *); static void init_marker(Obj_Entry *); static void init_pagesizes(Elf_Auxinfo **aux_info); static void init_rtld(caddr_t, Elf_Auxinfo **); static void initlist_add_neededs(Needed_Entry *, Objlist *, Objlist *); static void initlist_add_objects(Obj_Entry *, Obj_Entry *, Objlist *, Objlist *); static void initlist_for_loaded_obj(Obj_Entry *obj, Obj_Entry *tail, Objlist *list); static int initlist_objects_ifunc(Objlist *, bool, int, RtldLockState *); static void linkmap_add(Obj_Entry *); static void linkmap_delete(Obj_Entry *); static void load_filtees(Obj_Entry *, int flags, RtldLockState *); static void unload_filtees(Obj_Entry *, RtldLockState *); static int load_needed_objects(Obj_Entry *, int); static int load_preload_objects(const char *, bool); static int load_kpreload(const void *addr); static Obj_Entry *load_object(const char *, int fd, const Obj_Entry *, int); static void map_stacks_exec(RtldLockState *); static int obj_disable_relro(Obj_Entry *); static int obj_enforce_relro(Obj_Entry *); static void objlist_call_fini(Objlist *, Obj_Entry *, RtldLockState *); static void objlist_call_init(Objlist *, RtldLockState *); static void objlist_clear(Objlist *); static Objlist_Entry *objlist_find(Objlist *, const Obj_Entry *); static void objlist_init(Objlist *); static void objlist_push_head(Objlist *, Obj_Entry *); static void objlist_push_tail(Objlist *, Obj_Entry *); static void objlist_put_after(Objlist *, Obj_Entry *, Obj_Entry *); static void objlist_remove(Objlist *, Obj_Entry *); static int open_binary_fd(const char *argv0, bool search_in_path, const char **binpath_res); static int parse_args(char *argv[], int argc, bool *use_pathp, int *fdp, const char **argv0, bool *dir_ignore); static int parse_integer(const char *); static void *path_enumerate(const char *, path_enum_proc, const char *, void *); static void print_usage(const char *argv0); static void release_object(Obj_Entry *); static int relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, int flags, RtldLockState *lockstate); static int relocate_objects(Obj_Entry *, bool, Obj_Entry *, int, RtldLockState *); static int resolve_object_ifunc(Obj_Entry *, bool, int, RtldLockState *); static int rtld_dirname(const char *, char *); static int rtld_dirname_abs(const char *, char *); static void *rtld_dlopen(const char *name, int fd, int mode); static void rtld_exit(void); static void rtld_nop_exit(void); static char *search_library_path(const char *, const char *, const char *, int *); static char *search_library_pathfds(const char *, const char *, int *); static const void **get_program_var_addr(const char *, RtldLockState *); static void set_program_var(const char *, const void *); static int symlook_default(SymLook *, const Obj_Entry *refobj); static int symlook_global(SymLook *, DoneList *); static void symlook_init_from_req(SymLook *, const SymLook *); static int symlook_list(SymLook *, const Objlist *, DoneList *); static int symlook_needed(SymLook *, const Needed_Entry *, DoneList *); static int symlook_obj1_sysv(SymLook *, const Obj_Entry *); static int symlook_obj1_gnu(SymLook *, const Obj_Entry *); static void *tls_get_addr_slow(struct tcb *, int, size_t, bool) __noinline; static void trace_loaded_objects(Obj_Entry *, bool); static int try_fds_open(const char *name, const char *path); static void unlink_object(Obj_Entry *); static void unload_object(Obj_Entry *, RtldLockState *lockstate); static void unref_dag(Obj_Entry *); static void ref_dag(Obj_Entry *); static char *origin_subst_one(Obj_Entry *, char *, const char *, const char *, bool); static char *origin_subst(Obj_Entry *, const char *); static bool obj_resolve_origin(Obj_Entry *obj); static void preinit_main(void); static void rtld_recalc_bind_not(const char *); static void rtld_recalc_dangerous_ld_env(void); static void rtld_recalc_debug(const char *); static void rtld_recalc_path_rpath(const char *); static int rtld_verify_versions(const Objlist *); static int rtld_verify_object_versions(Obj_Entry *); static void object_add_name(Obj_Entry *, const char *); static int object_match_name(const Obj_Entry *, const char *); static void ld_utrace_log(int, void *, void *, size_t, int, const char *); static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info); static uint32_t gnu_hash(const char *); static bool matched_symbol(SymLook *, const Obj_Entry *, Sym_Match_Result *, const unsigned long); struct ld_env_var_desc; static void rtld_set_var_bind_not(struct ld_env_var_desc *lvd); static void rtld_set_var_bind_now(struct ld_env_var_desc *lvd); static void rtld_set_var_debug(struct ld_env_var_desc *lvd); static void rtld_set_var_dynamic_weak(struct ld_env_var_desc *lvd); static void rtld_set_var_libmap_disable(struct ld_env_var_desc *lvd); static void rtld_set_var_library_path(struct ld_env_var_desc *lvd); static void rtld_set_var_library_path_fds(struct ld_env_var_desc *lvd); static void rtld_set_var_library_path_rpath(struct ld_env_var_desc *lvd); static void rtld_set_var_loadfltr(struct ld_env_var_desc *lvd); void r_debug_state(struct r_debug *, struct link_map *) __noinline __exported; void _r_debug_postinit(struct link_map *) __noinline __exported; int __sys_openat(int, const char *, int, ...); /* * Data declarations. */ struct r_debug r_debug __exported; /* for GDB; */ static bool libmap_disable; /* Disable libmap */ static bool ld_loadfltr; /* Immediate filters processing */ static const char *libmap_override; /* Maps to use in addition to libmap.conf */ static bool trust; /* False for setuid and setgid programs */ static bool dangerous_ld_env; /* True if environment variables have been used to affect the libraries loaded */ bool ld_bind_not; /* Disable PLT update */ static const char *ld_bind_now; /* Environment variable for immediate binding */ static bool ld_dynamic_weak = true; /* True if non-weak definition overrides weak definition */ static const char *ld_library_path; /* Environment variable for search path */ static const char *ld_library_dirs; /* Environment variable for library descriptors */ static const char *ld_preload; /* Environment variable for libraries to load first */ static const char *ld_preload_fds; /* Environment variable for libraries represented by descriptors */ static const char *ld_elf_hints_path; /* Environment variable for alternative hints path */ static const char *ld_tracing; /* Called from ldd to print libs */ static const char *ld_utrace; /* Use utrace() to log events. */ static struct obj_entry_q obj_list; /* Queue of all loaded objects */ static Obj_Entry *obj_main; /* The main program shared object */ static Obj_Entry obj_rtld; /* The dynamic linker shared object */ static unsigned int obj_count; /* Number of objects in obj_list */ static unsigned int obj_loads; /* Number of loads of objects (gen count) */ size_t ld_static_tls_extra = /* Static TLS extra space (bytes) */ RTLD_STATIC_TLS_EXTRA; static Objlist list_global = /* Objects dlopened with RTLD_GLOBAL */ STAILQ_HEAD_INITIALIZER(list_global); static Objlist list_main = /* Objects loaded at program startup */ STAILQ_HEAD_INITIALIZER(list_main); static Objlist list_fini = /* Objects needing fini() calls */ STAILQ_HEAD_INITIALIZER(list_fini); Elf_Sym sym_zero; /* For resolving undefined weak refs. */ #define GDB_STATE(s, m) \ r_debug.r_state = s; \ r_debug_state(&r_debug, m); extern Elf_Dyn _DYNAMIC; #pragma weak _DYNAMIC int dlclose(void *) __exported; char *dlerror(void) __exported; void *dlopen(const char *, int) __exported; void *fdlopen(int, int) __exported; void *dlsym(void *, const char *) __exported; dlfunc_t dlfunc(void *, const char *) __exported; void *dlvsym(void *, const char *, const char *) __exported; int dladdr(const void *, Dl_info *) __exported; void dllockinit(void *, void *(*)(void *), void (*)(void *), void (*)(void *), void (*)(void *), void (*)(void *), void (*)(void *)) __exported; int dlinfo(void *, int, void *) __exported; int _dl_iterate_phdr_locked(__dl_iterate_hdr_callback, void *) __exported; int dl_iterate_phdr(__dl_iterate_hdr_callback, void *) __exported; int _rtld_addr_phdr(const void *, struct dl_phdr_info *) __exported; int _rtld_get_stack_prot(void) __exported; int _rtld_is_dlopened(void *) __exported; void _rtld_error(const char *, ...) __exported; const char *rtld_get_var(const char *name) __exported; int rtld_set_var(const char *name, const char *val) __exported; /* Only here to fix -Wmissing-prototypes warnings */ int __getosreldate(void); func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp); Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff); int npagesizes; static int osreldate; size_t *pagesizes; size_t page_size; static int stack_prot = PROT_READ | PROT_WRITE | PROT_EXEC; static int max_stack_flags; /* * Global declarations normally provided by crt1. The dynamic linker is * not built with crt1, so we have to provide them ourselves. */ char *__progname; char **environ; /* * Used to pass argc, argv to init functions. */ int main_argc; char **main_argv; /* * Globals to control TLS allocation. */ size_t tls_last_offset; /* Static TLS offset of last module */ size_t tls_last_size; /* Static TLS size of last module */ size_t tls_static_space; /* Static TLS space allocated */ static size_t tls_static_max_align; Elf_Addr tls_dtv_generation = 1; /* Used to detect when dtv size changes */ int tls_max_index = 1; /* Largest module index allocated */ static TAILQ_HEAD(, tcb_list_entry) tcb_list = TAILQ_HEAD_INITIALIZER(tcb_list); static size_t tcb_list_entry_offset; static bool ld_library_path_rpath = false; bool ld_fast_sigblock = false; /* * Globals for path names, and such */ const char *ld_elf_hints_default = _PATH_ELF_HINTS; const char *ld_path_libmap_conf = _PATH_LIBMAP_CONF; const char *ld_path_rtld = _PATH_RTLD; const char *ld_standard_library_path = STANDARD_LIBRARY_PATH; const char *ld_env_prefix = LD_; static void (*rtld_exit_ptr)(void); /* * Fill in a DoneList with an allocation large enough to hold all of * the currently-loaded objects. Keep this as a macro since it calls * alloca and we want that to occur within the scope of the caller. */ #define donelist_init(dlp) \ ((dlp)->objs = alloca(obj_count * sizeof(dlp)->objs[0]), \ assert((dlp)->objs != NULL), (dlp)->num_alloc = obj_count, \ (dlp)->num_used = 0) #define LD_UTRACE(e, h, mb, ms, r, n) \ do { \ if (ld_utrace != NULL) \ ld_utrace_log(e, h, mb, ms, r, n); \ } while (0) static void ld_utrace_log(int event, void *handle, void *mapbase, size_t mapsize, int refcnt, const char *name) { struct utrace_rtld ut; static const char rtld_utrace_sig[RTLD_UTRACE_SIG_SZ] __nonstring = RTLD_UTRACE_SIG; memset(&ut, 0, sizeof(ut)); /* clear holes */ memcpy(ut.sig, rtld_utrace_sig, sizeof(ut.sig)); ut.event = event; ut.handle = handle; ut.mapbase = mapbase; ut.mapsize = mapsize; ut.refcnt = refcnt; if (name != NULL) strlcpy(ut.name, name, sizeof(ut.name)); utrace(&ut, sizeof(ut)); } struct ld_env_var_desc { const char *const n; const char *val; const bool unsecure : 1; const bool can_update : 1; bool owned : 1; void (*const on_update)(struct ld_env_var_desc *); }; #define LD_ENV_DESC(var, unsec, ...) \ [LD_##var] = { .n = #var, .unsecure = unsec, __VA_ARGS__ } static struct ld_env_var_desc ld_env_vars[] = { LD_ENV_DESC(BIND_NOW, false, .can_update = true, .on_update = rtld_set_var_bind_now), LD_ENV_DESC(PRELOAD, true), LD_ENV_DESC(LIBMAP, true), LD_ENV_DESC(LIBRARY_PATH, true, .can_update = true, .on_update = rtld_set_var_library_path), LD_ENV_DESC(LIBRARY_PATH_FDS, true, .can_update = true, .on_update = rtld_set_var_library_path_fds), LD_ENV_DESC(LIBMAP_DISABLE, true, .can_update = true, .on_update = rtld_set_var_libmap_disable), LD_ENV_DESC(BIND_NOT, true, .can_update = true, .on_update = rtld_set_var_bind_not), LD_ENV_DESC(DEBUG, true, .can_update = true, .on_update = rtld_set_var_debug), LD_ENV_DESC(ELF_HINTS_PATH, true), LD_ENV_DESC(LOADFLTR, true, .can_update = true, .on_update = rtld_set_var_loadfltr), LD_ENV_DESC(LIBRARY_PATH_RPATH, true, .can_update = true, .on_update = rtld_set_var_library_path_rpath), LD_ENV_DESC(PRELOAD_FDS, true), LD_ENV_DESC(DYNAMIC_WEAK, true, .can_update = true, .on_update = rtld_set_var_dynamic_weak), LD_ENV_DESC(TRACE_LOADED_OBJECTS, false), LD_ENV_DESC(UTRACE, false, .can_update = true), LD_ENV_DESC(DUMP_REL_PRE, false, .can_update = true), LD_ENV_DESC(DUMP_REL_POST, false, .can_update = true), LD_ENV_DESC(TRACE_LOADED_OBJECTS_PROGNAME, false), LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT1, false), LD_ENV_DESC(TRACE_LOADED_OBJECTS_FMT2, false), LD_ENV_DESC(TRACE_LOADED_OBJECTS_ALL, false), LD_ENV_DESC(SHOW_AUXV, true), LD_ENV_DESC(STATIC_TLS_EXTRA, false), LD_ENV_DESC(NO_DL_ITERATE_PHDR_AFTER_FORK, false), }; const char * ld_get_env_var(int idx) { return (ld_env_vars[idx].val); } static const char * rtld_get_env_val(char **env, const char *name, size_t name_len) { char **m, *n, *v; for (m = env; *m != NULL; m++) { n = *m; v = strchr(n, '='); if (v == NULL) { /* corrupt environment? */ continue; } if (v - n == (ptrdiff_t)name_len && strncmp(name, n, name_len) == 0) return (v + 1); } return (NULL); } static void rtld_init_env_vars_for_prefix(char **env, const char *env_prefix) { struct ld_env_var_desc *lvd; size_t prefix_len, nlen; char **m, *n, *v; int i; prefix_len = strlen(env_prefix); for (m = env; *m != NULL; m++) { n = *m; if (strncmp(env_prefix, n, prefix_len) != 0) { /* Not a rtld environment variable. */ continue; } n += prefix_len; v = strchr(n, '='); if (v == NULL) { /* corrupt environment? */ continue; } for (i = 0; i < (int)nitems(ld_env_vars); i++) { lvd = &ld_env_vars[i]; if (lvd->val != NULL) { /* Saw higher-priority variable name already. */ continue; } nlen = strlen(lvd->n); if (v - n == (ptrdiff_t)nlen && strncmp(lvd->n, n, nlen) == 0) { lvd->val = v + 1; break; } } } } static void rtld_init_env_vars(char **env) { rtld_init_env_vars_for_prefix(env, ld_env_prefix); } static void set_ld_elf_hints_path(void) { if (ld_elf_hints_path == NULL || strlen(ld_elf_hints_path) == 0) ld_elf_hints_path = ld_elf_hints_default; } uintptr_t rtld_round_page(uintptr_t x) { return (roundup2(x, page_size)); } uintptr_t rtld_trunc_page(uintptr_t x) { return (rounddown2(x, page_size)); } /* * Main entry point for dynamic linking. The first argument is the * stack pointer. The stack is expected to be laid out as described * in the SVR4 ABI specification, Intel 386 Processor Supplement. * Specifically, the stack pointer points to a word containing * ARGC. Following that in the stack is a null-terminated sequence * of pointers to argument strings. Then comes a null-terminated * sequence of pointers to environment strings. Finally, there is a * sequence of "auxiliary vector" entries. * * The second argument points to a place to store the dynamic linker's * exit procedure pointer and the third to a place to store the main * program's object. * * The return value is the main program's entry point. */ func_ptr_type _rtld(Elf_Addr *sp, func_ptr_type *exit_proc, Obj_Entry **objp) { Elf_Auxinfo *aux, *auxp, *auxpf, *aux_info[AT_COUNT], auxtmp; Objlist_Entry *entry; Obj_Entry *last_interposer, *obj, *preload_tail; const Elf_Phdr *phdr; Objlist initlist; RtldLockState lockstate; struct stat st; Elf_Addr *argcp; char **argv, **env, **envp, *kexecpath; const char *argv0, *binpath, *static_tls_extra; struct ld_env_var_desc *lvd; caddr_t imgentry; char buf[MAXPATHLEN]; int argc, fd, i, mib[4], old_osrel, osrel, phnum, rtld_argc; size_t sz; bool dir_enable, dir_ignore, direct_exec, explicit_fd, search_in_path; /* * On entry, the dynamic linker itself has not been relocated yet. * Be very careful not to reference any global data until after * init_rtld has returned. It is OK to reference file-scope statics * and string constants, and to call static and global functions. */ /* Find the auxiliary vector on the stack. */ argcp = sp; argc = *sp++; argv = (char **)sp; sp += argc + 1; /* Skip over arguments and NULL terminator */ env = (char **)sp; while (*sp++ != 0) /* Skip over environment, and NULL terminator */ ; aux = (Elf_Auxinfo *)sp; /* Digest the auxiliary vector. */ for (i = 0; i < AT_COUNT; i++) aux_info[i] = NULL; for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { if (auxp->a_type < AT_COUNT) aux_info[auxp->a_type] = auxp; } arch_fix_auxv(aux, aux_info); /* Initialize and relocate ourselves. */ assert(aux_info[AT_BASE] != NULL); init_rtld((caddr_t)aux_info[AT_BASE]->a_un.a_ptr, aux_info); dlerror_dflt_init(); __progname = obj_rtld.path; argv0 = argv[0] != NULL ? argv[0] : "(null)"; environ = env; main_argc = argc; main_argv = argv; if (aux_info[AT_BSDFLAGS] != NULL && (aux_info[AT_BSDFLAGS]->a_un.a_val & ELF_BSDF_SIGFASTBLK) != 0) ld_fast_sigblock = true; trust = !issetugid(); direct_exec = false; md_abi_variant_hook(aux_info); rtld_init_env_vars(env); fd = -1; if (aux_info[AT_EXECFD] != NULL) { fd = aux_info[AT_EXECFD]->a_un.a_val; } else { assert(aux_info[AT_PHDR] != NULL); phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; if (phdr == obj_rtld.phdr) { if (!trust) { _rtld_error( "Tainted process refusing to run binary %s", argv0); rtld_die(); } direct_exec = true; dbg("opening main program in direct exec mode"); if (argc >= 2) { rtld_argc = parse_args(argv, argc, &search_in_path, &fd, &argv0, &dir_ignore); explicit_fd = (fd != -1); binpath = NULL; if (!explicit_fd) fd = open_binary_fd(argv0, search_in_path, &binpath); if (fstat(fd, &st) == -1) { _rtld_error( "Failed to fstat FD %d (%s): %s", fd, explicit_fd ? "user-provided descriptor" : argv0, rtld_strerror(errno)); rtld_die(); } /* * Rough emulation of the permission checks done * by execve(2), only Unix DACs are checked, * ACLs are ignored. Preserve the semantic of * disabling owner to execute if owner x bit is * cleared, even if others x bit is enabled. * mmap(2) does not allow to mmap with PROT_EXEC * if binary' file comes from noexec mount. We * cannot set a text reference on the binary. */ dir_enable = false; if (st.st_uid == geteuid()) { if ((st.st_mode & S_IXUSR) != 0) dir_enable = true; } else if (st.st_gid == getegid()) { if ((st.st_mode & S_IXGRP) != 0) dir_enable = true; } else if ((st.st_mode & S_IXOTH) != 0) { dir_enable = true; } if (!dir_enable && !dir_ignore) { _rtld_error( "No execute permission for binary %s", argv0); rtld_die(); } /* * For direct exec mode, argv[0] is the * interpreter name, we must remove it and shift * arguments left before invoking binary main. * Since stack layout places environment * pointers and aux vectors right after the * terminating NULL, we must shift environment * and aux as well. */ main_argc = argc - rtld_argc; for (i = 0; i <= main_argc; i++) argv[i] = argv[i + rtld_argc]; *argcp -= rtld_argc; environ = env = envp = argv + main_argc + 1; dbg("move env from %p to %p", envp + rtld_argc, envp); do { *envp = *(envp + rtld_argc); } while (*envp++ != NULL); aux = auxp = (Elf_Auxinfo *)envp; auxpf = (Elf_Auxinfo *)(envp + rtld_argc); dbg("move aux from %p to %p", auxpf, aux); /* * XXXKIB insert place for AT_EXECPATH if not * present */ for (;; auxp++, auxpf++) { /* * NB: Use a temporary since *auxpf and * *auxp overlap if rtld_argc is 1 */ auxtmp = *auxpf; *auxp = auxtmp; if (auxp->a_type == AT_NULL) break; } /* * Since the auxiliary vector has moved, * redigest it. */ for (i = 0; i < AT_COUNT; i++) aux_info[i] = NULL; for (auxp = aux; auxp->a_type != AT_NULL; auxp++) { if (auxp->a_type < AT_COUNT) aux_info[auxp->a_type] = auxp; } /* * Point AT_EXECPATH auxv and aux_info to the * binary path. */ if (binpath == NULL) { aux_info[AT_EXECPATH] = NULL; } else { if (aux_info[AT_EXECPATH] == NULL) { aux_info[AT_EXECPATH] = xmalloc( sizeof(Elf_Auxinfo)); aux_info[AT_EXECPATH]->a_type = AT_EXECPATH; } aux_info[AT_EXECPATH]->a_un.a_ptr = __DECONST(void *, binpath); } } else { _rtld_error("No binary"); rtld_die(); } } } ld_bind_now = ld_get_env_var(LD_BIND_NOW); /* * If the process is tainted, then we un-set the dangerous environment * variables. The process will be marked as tainted until setuid(2) * is called. If any child process calls setuid(2) we do not want any * future processes to honor the potentially un-safe variables. */ if (!trust) { for (i = 0; i < (int)nitems(ld_env_vars); i++) { lvd = &ld_env_vars[i]; if (lvd->unsecure) lvd->val = NULL; } } rtld_recalc_debug(ld_get_env_var(LD_DEBUG)); rtld_recalc_bind_not(ld_get_env_var(LD_BIND_NOT)); ld_dynamic_weak = ld_get_env_var(LD_DYNAMIC_WEAK) == NULL; libmap_disable = ld_get_env_var(LD_LIBMAP_DISABLE) != NULL; libmap_override = ld_get_env_var(LD_LIBMAP); ld_library_path = ld_get_env_var(LD_LIBRARY_PATH); ld_library_dirs = ld_get_env_var(LD_LIBRARY_PATH_FDS); ld_preload = ld_get_env_var(LD_PRELOAD); ld_preload_fds = ld_get_env_var(LD_PRELOAD_FDS); ld_elf_hints_path = ld_get_env_var(LD_ELF_HINTS_PATH); ld_loadfltr = ld_get_env_var(LD_LOADFLTR) != NULL; rtld_recalc_path_rpath(ld_get_env_var(LD_LIBRARY_PATH_RPATH)); static_tls_extra = ld_get_env_var(LD_STATIC_TLS_EXTRA); if (static_tls_extra != NULL && static_tls_extra[0] != '\0') { sz = parse_integer(static_tls_extra); if (sz >= RTLD_STATIC_TLS_EXTRA && sz <= SIZE_T_MAX) ld_static_tls_extra = sz; } rtld_recalc_dangerous_ld_env(); ld_tracing = ld_get_env_var(LD_TRACE_LOADED_OBJECTS); ld_utrace = ld_get_env_var(LD_UTRACE); set_ld_elf_hints_path(); dbg("%s is initialized, base address = %p", __progname, (caddr_t)aux_info[AT_BASE]->a_un.a_ptr); dbg("RTLD dynamic = %p", obj_rtld.dynamic); dbg("RTLD pltgot = %p", obj_rtld.pltgot); dbg("initializing thread locks"); lockdflt_init(); /* * Load the main program, or process its program header if it is * already loaded. */ if (fd != -1) { /* Load the main program. */ dbg("loading main program"); obj_main = map_object(fd, argv0, NULL, true); close(fd); if (obj_main == NULL) rtld_die(); max_stack_flags = obj_main->stack_flags; } else { /* Main program already loaded. */ dbg("processing main program's program header"); assert(aux_info[AT_PHDR] != NULL); phdr = (const Elf_Phdr *)aux_info[AT_PHDR]->a_un.a_ptr; assert(aux_info[AT_PHNUM] != NULL); phnum = aux_info[AT_PHNUM]->a_un.a_val; assert(aux_info[AT_PHENT] != NULL); assert(aux_info[AT_PHENT]->a_un.a_val == sizeof(Elf_Phdr)); assert(aux_info[AT_ENTRY] != NULL); imgentry = (caddr_t)aux_info[AT_ENTRY]->a_un.a_ptr; if ((obj_main = digest_phdr(phdr, phnum, imgentry, argv0)) == NULL) rtld_die(); } if (aux_info[AT_EXECPATH] != NULL && fd == -1) { kexecpath = aux_info[AT_EXECPATH]->a_un.a_ptr; dbg("AT_EXECPATH %p %s", kexecpath, kexecpath); if (kexecpath[0] == '/') obj_main->path = kexecpath; else if (getcwd(buf, sizeof(buf)) == NULL || strlcat(buf, "/", sizeof(buf)) >= sizeof(buf) || strlcat(buf, kexecpath, sizeof(buf)) >= sizeof(buf)) obj_main->path = xstrdup(argv0); else obj_main->path = xstrdup(buf); } else { dbg("No AT_EXECPATH or direct exec"); obj_main->path = xstrdup(argv0); } dbg("obj_main path %s", obj_main->path); obj_main->mainprog = true; if (aux_info[AT_STACKPROT] != NULL && aux_info[AT_STACKPROT]->a_un.a_val != 0) stack_prot = aux_info[AT_STACKPROT]->a_un.a_val; #ifndef COMPAT_libcompat /* * Get the actual dynamic linker pathname from the executable if * possible. (It should always be possible.) That ensures that * gdb will find the right dynamic linker even if a non-standard * one is being used. */ if (obj_main->interp != NULL && strcmp(obj_main->interp, obj_rtld.path) != 0) { free(obj_rtld.path); obj_rtld.path = xstrdup(obj_main->interp); __progname = obj_rtld.path; } #endif if (!digest_dynamic(obj_main, 0)) rtld_die(); dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj_main->path, obj_main->valid_hash_sysv, obj_main->valid_hash_gnu, obj_main->dynsymcount); linkmap_add(obj_main); linkmap_add(&obj_rtld); LD_UTRACE(UTRACE_LOAD_OBJECT, obj_main, obj_main->mapbase, obj_main->mapsize, 0, obj_main->path); LD_UTRACE(UTRACE_LOAD_OBJECT, &obj_rtld, obj_rtld.mapbase, obj_rtld.mapsize, 0, obj_rtld.path); /* Link the main program into the list of objects. */ TAILQ_INSERT_HEAD(&obj_list, obj_main, next); obj_count++; obj_loads++; /* Initialize a fake symbol for resolving undefined weak references. */ sym_zero.st_info = ELF_ST_INFO(STB_GLOBAL, STT_NOTYPE); sym_zero.st_shndx = SHN_UNDEF; sym_zero.st_value = -(uintptr_t)obj_main->relocbase; if (!libmap_disable) libmap_disable = (bool)lm_init(libmap_override); if (aux_info[AT_KPRELOAD] != NULL && aux_info[AT_KPRELOAD]->a_un.a_ptr != NULL) { dbg("loading kernel vdso"); if (load_kpreload(aux_info[AT_KPRELOAD]->a_un.a_ptr) == -1) rtld_die(); } dbg("loading LD_PRELOAD_FDS libraries"); if (load_preload_objects(ld_preload_fds, true) == -1) rtld_die(); dbg("loading LD_PRELOAD libraries"); if (load_preload_objects(ld_preload, false) == -1) rtld_die(); preload_tail = globallist_curr(TAILQ_LAST(&obj_list, obj_entry_q)); dbg("loading needed objects"); if (load_needed_objects(obj_main, ld_tracing != NULL ? RTLD_LO_TRACE : 0) == -1) rtld_die(); /* Make a list of all objects loaded at startup. */ last_interposer = obj_main; TAILQ_FOREACH(obj, &obj_list, next) { if (obj->marker) continue; if (obj->z_interpose && obj != obj_main) { objlist_put_after(&list_main, last_interposer, obj); last_interposer = obj; } else { objlist_push_tail(&list_main, obj); } obj->refcount++; } dbg("checking for required versions"); if (rtld_verify_versions(&list_main) == -1 && !ld_tracing) rtld_die(); if (ld_get_env_var(LD_SHOW_AUXV) != NULL) dump_auxv(aux_info); if (ld_tracing) { /* We're done */ trace_loaded_objects(obj_main, true); exit(0); } if (ld_get_env_var(LD_DUMP_REL_PRE) != NULL) { dump_relocations(obj_main); exit(0); } /* * Processing tls relocations requires having the tls offsets * initialized. Prepare offsets before starting initial * relocation processing. */ dbg("initializing initial thread local storage offsets"); STAILQ_FOREACH(entry, &list_main, link) { /* * Allocate all the initial objects out of the static TLS * block even if they didn't ask for it. */ allocate_tls_offset(entry->obj); } if (!allocate_tls_offset_common(&tcb_list_entry_offset, sizeof(struct tcb_list_entry), _Alignof(struct tcb_list_entry), 0)) { /* * This should be impossible as the static block size is not * yet fixed, but catch and diagnose it failing if that ever * changes or somehow turns out to be false. */ _rtld_error("Could not allocate offset for tcb_list_entry"); rtld_die(); } dbg("tcb_list_entry_offset %zu", tcb_list_entry_offset); if (relocate_objects(obj_main, ld_bind_now != NULL && *ld_bind_now != '\0', &obj_rtld, SYMLOOK_EARLY, NULL) == -1) rtld_die(); dbg("doing copy relocations"); if (do_copy_relocations(obj_main) == -1) rtld_die(); if (ld_get_env_var(LD_DUMP_REL_POST) != NULL) { dump_relocations(obj_main); exit(0); } ifunc_init(aux_info); /* * Setup TLS for main thread. This must be done after the * relocations are processed, since tls initialization section * might be the subject for relocations. */ dbg("initializing initial thread local storage"); allocate_initial_tls(globallist_curr(TAILQ_FIRST(&obj_list))); dbg("initializing key program variables"); set_program_var("__progname", argv[0] != NULL ? basename(argv[0]) : ""); set_program_var("environ", env); set_program_var("__elf_aux_vector", aux); /* Make a list of init functions to call. */ objlist_init(&initlist); initlist_for_loaded_obj(globallist_curr(TAILQ_FIRST(&obj_list)), preload_tail, &initlist); r_debug_state(NULL, &obj_main->linkmap); /* say hello to gdb! */ map_stacks_exec(NULL); if (!obj_main->crt_no_init) { /* * Make sure we don't call the main program's init and fini * functions for binaries linked with old crt1 which calls * _init itself. */ obj_main->init = obj_main->fini = 0; obj_main->preinit_array = obj_main->init_array = obj_main->fini_array = NULL; } if (direct_exec) { /* Set osrel for direct-execed binary */ mib[0] = CTL_KERN; mib[1] = KERN_PROC; mib[2] = KERN_PROC_OSREL; mib[3] = getpid(); osrel = obj_main->osrel; sz = sizeof(old_osrel); dbg("setting osrel to %d", osrel); (void)sysctl(mib, 4, &old_osrel, &sz, &osrel, sizeof(osrel)); } wlock_acquire(rtld_bind_lock, &lockstate); dbg("resolving ifuncs"); if (initlist_objects_ifunc(&initlist, ld_bind_now != NULL && *ld_bind_now != '\0', SYMLOOK_EARLY, &lockstate) == -1) rtld_die(); rtld_exit_ptr = rtld_exit; if (obj_main->crt_no_init) preinit_main(); objlist_call_init(&initlist, &lockstate); _r_debug_postinit(&obj_main->linkmap); objlist_clear(&initlist); dbg("loading filtees"); TAILQ_FOREACH(obj, &obj_list, next) { if (obj->marker) continue; if (ld_loadfltr || obj->z_loadfltr) load_filtees(obj, 0, &lockstate); } dbg("enforcing main obj relro"); if (obj_enforce_relro(obj_main) == -1) rtld_die(); lock_release(rtld_bind_lock, &lockstate); dbg("transferring control to program entry point = %p", obj_main->entry); /* Return the exit procedure and the program entry point. */ *exit_proc = rtld_exit_ptr; *objp = obj_main; return ((func_ptr_type)obj_main->entry); } void * rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def) { void *ptr; Elf_Addr target; ptr = (void *)make_function_pointer(def, obj); target = call_ifunc_resolver(ptr); return ((void *)target); } Elf_Addr _rtld_bind(Obj_Entry *obj, Elf_Size reloff) { const Elf_Rel *rel; const Elf_Sym *def; const Obj_Entry *defobj; Elf_Addr *where; Elf_Addr target; RtldLockState lockstate; relock: rlock_acquire(rtld_bind_lock, &lockstate); if (sigsetjmp(lockstate.env, 0) != 0) lock_upgrade(rtld_bind_lock, &lockstate); if (obj->pltrel) rel = (const Elf_Rel *)((const char *)obj->pltrel + reloff); else rel = (const Elf_Rel *)((const char *)obj->pltrela + reloff); where = (Elf_Addr *)(obj->relocbase + rel->r_offset); def = find_symdef(ELF_R_SYM(rel->r_info), obj, &defobj, SYMLOOK_IN_PLT, NULL, &lockstate); if (def == NULL) rtld_die(); if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) { if (lockstate_wlocked(&lockstate)) { lock_release(rtld_bind_lock, &lockstate); goto relock; } target = (Elf_Addr)rtld_resolve_ifunc(defobj, def); } else { target = (Elf_Addr)(defobj->relocbase + def->st_value); } dbg("\"%s\" in \"%s\" ==> %p in \"%s\"", defobj->strtab + def->st_name, obj->path == NULL ? NULL : basename(obj->path), (void *)target, defobj->path == NULL ? NULL : basename(defobj->path)); /* * Write the new contents for the jmpslot. Note that depending on * architecture, the value which we need to return back to the * lazy binding trampoline may or may not be the target * address. The value returned from reloc_jmpslot() is the value * that the trampoline needs. */ target = reloc_jmpslot(where, target, defobj, obj, rel); lock_release(rtld_bind_lock, &lockstate); return (target); } /* * Error reporting function. Use it like printf. If formats the message * into a buffer, and sets things up so that the next call to dlerror() * will return the message. */ void _rtld_error(const char *fmt, ...) { va_list ap; va_start(ap, fmt); rtld_vsnprintf(lockinfo.dlerror_loc(), lockinfo.dlerror_loc_sz, fmt, ap); va_end(ap); *lockinfo.dlerror_seen() = 0; dbg("rtld_error: %s", lockinfo.dlerror_loc()); LD_UTRACE(UTRACE_RTLD_ERROR, NULL, NULL, 0, 0, lockinfo.dlerror_loc()); } /* * Return a dynamically-allocated copy of the current error message, if any. */ static struct dlerror_save * errmsg_save(void) { struct dlerror_save *res; res = xmalloc(sizeof(*res)); res->seen = *lockinfo.dlerror_seen(); if (res->seen == 0) res->msg = xstrdup(lockinfo.dlerror_loc()); return (res); } /* * Restore the current error message from a copy which was previously saved * by errmsg_save(). The copy is freed. */ static void errmsg_restore(struct dlerror_save *saved_msg) { if (saved_msg == NULL || saved_msg->seen == 1) { *lockinfo.dlerror_seen() = 1; } else { *lockinfo.dlerror_seen() = 0; strlcpy(lockinfo.dlerror_loc(), saved_msg->msg, lockinfo.dlerror_loc_sz); free(saved_msg->msg); } free(saved_msg); } static const char * basename(const char *name) { const char *p; p = strrchr(name, '/'); return (p != NULL ? p + 1 : name); } static struct utsname uts; static char * origin_subst_one(Obj_Entry *obj, char *real, const char *kw, const char *subst, bool may_free) { char *p, *p1, *res, *resp; int subst_len, kw_len, subst_count, old_len, new_len; kw_len = strlen(kw); /* * First, count the number of the keyword occurrences, to * preallocate the final string. */ for (p = real, subst_count = 0;; p = p1 + kw_len, subst_count++) { p1 = strstr(p, kw); if (p1 == NULL) break; } /* * If the keyword is not found, just return. * * Return non-substituted string if resolution failed. We * cannot do anything more reasonable, the failure mode of the * caller is unresolved library anyway. */ if (subst_count == 0 || (obj != NULL && !obj_resolve_origin(obj))) return (may_free ? real : xstrdup(real)); if (obj != NULL) subst = obj->origin_path; /* * There is indeed something to substitute. Calculate the * length of the resulting string, and allocate it. */ subst_len = strlen(subst); old_len = strlen(real); new_len = old_len + (subst_len - kw_len) * subst_count; res = xmalloc(new_len + 1); /* * Now, execute the substitution loop. */ for (p = real, resp = res, *resp = '\0';;) { p1 = strstr(p, kw); if (p1 != NULL) { /* Copy the prefix before keyword. */ memcpy(resp, p, p1 - p); resp += p1 - p; /* Keyword replacement. */ memcpy(resp, subst, subst_len); resp += subst_len; *resp = '\0'; p = p1 + kw_len; } else break; } /* Copy to the end of string and finish. */ strcat(resp, p); if (may_free) free(real); return (res); } static const struct { const char *kw; bool pass_obj; const char *subst; } tokens[] = { { .kw = "$ORIGIN", .pass_obj = true, .subst = NULL }, { .kw = "${ORIGIN}", .pass_obj = true, .subst = NULL }, { .kw = "$OSNAME", .pass_obj = false, .subst = uts.sysname }, { .kw = "${OSNAME}", .pass_obj = false, .subst = uts.sysname }, { .kw = "$OSREL", .pass_obj = false, .subst = uts.release }, { .kw = "${OSREL}", .pass_obj = false, .subst = uts.release }, { .kw = "$PLATFORM", .pass_obj = false, .subst = uts.machine }, { .kw = "${PLATFORM}", .pass_obj = false, .subst = uts.machine }, { .kw = "$LIB", .pass_obj = false, .subst = TOKEN_LIB }, { .kw = "${LIB}", .pass_obj = false, .subst = TOKEN_LIB }, }; static char * origin_subst(Obj_Entry *obj, const char *real) { char *res; int i; if (obj == NULL || !trust) return (xstrdup(real)); if (uts.sysname[0] == '\0') { if (uname(&uts) != 0) { _rtld_error("utsname failed: %d", errno); return (NULL); } } /* __DECONST is safe here since without may_free real is unchanged */ res = __DECONST(char *, real); for (i = 0; i < (int)nitems(tokens); i++) { res = origin_subst_one(tokens[i].pass_obj ? obj : NULL, res, tokens[i].kw, tokens[i].subst, i != 0); } return (res); } void rtld_die(void) { const char *msg = dlerror(); if (msg == NULL) msg = "Fatal error"; rtld_fdputstr(STDERR_FILENO, _BASENAME_RTLD ": "); rtld_fdputstr(STDERR_FILENO, msg); rtld_fdputchar(STDERR_FILENO, '\n'); _exit(1); } /* * Process a shared object's DYNAMIC section, and save the important * information in its Obj_Entry structure. */ static void digest_dynamic1(Obj_Entry *obj, int early, const Elf_Dyn **dyn_rpath, const Elf_Dyn **dyn_soname, const Elf_Dyn **dyn_runpath) { const Elf_Dyn *dynp; Needed_Entry **needed_tail = &obj->needed; Needed_Entry **needed_filtees_tail = &obj->needed_filtees; Needed_Entry **needed_aux_filtees_tail = &obj->needed_aux_filtees; const Elf_Hashelt *hashtab; const Elf32_Word *hashval; Elf32_Word bkt, nmaskwords; int bloom_size32; int plttype = DT_REL; *dyn_rpath = NULL; *dyn_soname = NULL; *dyn_runpath = NULL; obj->bind_now = false; dynp = obj->dynamic; if (dynp == NULL) return; for (; dynp->d_tag != DT_NULL; dynp++) { switch (dynp->d_tag) { case DT_REL: obj->rel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); break; case DT_RELSZ: obj->relsize = dynp->d_un.d_val; break; case DT_RELENT: assert(dynp->d_un.d_val == sizeof(Elf_Rel)); break; case DT_JMPREL: obj->pltrel = (const Elf_Rel *)(obj->relocbase + dynp->d_un.d_ptr); break; case DT_PLTRELSZ: obj->pltrelsize = dynp->d_un.d_val; break; case DT_RELA: obj->rela = (const Elf_Rela *)(obj->relocbase + dynp->d_un.d_ptr); break; case DT_RELASZ: obj->relasize = dynp->d_un.d_val; break; case DT_RELAENT: assert(dynp->d_un.d_val == sizeof(Elf_Rela)); break; case DT_RELR: obj->relr = (const Elf_Relr *)(obj->relocbase + dynp->d_un.d_ptr); break; case DT_RELRSZ: obj->relrsize = dynp->d_un.d_val; break; case DT_RELRENT: assert(dynp->d_un.d_val == sizeof(Elf_Relr)); break; case DT_PLTREL: plttype = dynp->d_un.d_val; assert( dynp->d_un.d_val == DT_REL || plttype == DT_RELA); break; case DT_SYMTAB: obj->symtab = (const Elf_Sym *)(obj->relocbase + dynp->d_un.d_ptr); break; case DT_SYMENT: assert(dynp->d_un.d_val == sizeof(Elf_Sym)); break; case DT_STRTAB: obj->strtab = (const char *)(obj->relocbase + dynp->d_un.d_ptr); break; case DT_STRSZ: obj->strsize = dynp->d_un.d_val; break; case DT_VERNEED: obj->verneed = (const Elf_Verneed *)(obj->relocbase + dynp->d_un.d_val); break; case DT_VERNEEDNUM: obj->verneednum = dynp->d_un.d_val; break; case DT_VERDEF: obj->verdef = (const Elf_Verdef *)(obj->relocbase + dynp->d_un.d_val); break; case DT_VERDEFNUM: obj->verdefnum = dynp->d_un.d_val; break; case DT_VERSYM: obj->versyms = (const Elf_Versym *)(obj->relocbase + dynp->d_un.d_val); break; case DT_HASH: { hashtab = (const Elf_Hashelt *)(obj->relocbase + dynp->d_un.d_ptr); obj->nbuckets = hashtab[0]; obj->nchains = hashtab[1]; obj->buckets = hashtab + 2; obj->chains = obj->buckets + obj->nbuckets; obj->valid_hash_sysv = obj->nbuckets > 0 && obj->nchains > 0 && obj->buckets != NULL; } break; case DT_GNU_HASH: { hashtab = (const Elf_Hashelt *)(obj->relocbase + dynp->d_un.d_ptr); obj->nbuckets_gnu = hashtab[0]; obj->symndx_gnu = hashtab[1]; nmaskwords = hashtab[2]; bloom_size32 = (__ELF_WORD_SIZE / 32) * nmaskwords; obj->maskwords_bm_gnu = nmaskwords - 1; obj->shift2_gnu = hashtab[3]; obj->bloom_gnu = (const Elf_Addr *)(hashtab + 4); obj->buckets_gnu = hashtab + 4 + bloom_size32; obj->chain_zero_gnu = obj->buckets_gnu + obj->nbuckets_gnu - obj->symndx_gnu; /* Number of bitmask words is required to be power of 2 */ obj->valid_hash_gnu = powerof2(nmaskwords) && obj->nbuckets_gnu > 0 && obj->buckets_gnu != NULL; } break; case DT_NEEDED: if (!obj->rtld) { Needed_Entry *nep = NEW(Needed_Entry); nep->name = dynp->d_un.d_val; nep->obj = NULL; nep->next = NULL; *needed_tail = nep; needed_tail = &nep->next; } break; case DT_FILTER: if (!obj->rtld) { Needed_Entry *nep = NEW(Needed_Entry); nep->name = dynp->d_un.d_val; nep->obj = NULL; nep->next = NULL; *needed_filtees_tail = nep; needed_filtees_tail = &nep->next; if (obj->linkmap.l_refname == NULL) obj->linkmap.l_refname = (char *)dynp->d_un.d_val; } break; case DT_AUXILIARY: if (!obj->rtld) { Needed_Entry *nep = NEW(Needed_Entry); nep->name = dynp->d_un.d_val; nep->obj = NULL; nep->next = NULL; *needed_aux_filtees_tail = nep; needed_aux_filtees_tail = &nep->next; } break; case DT_PLTGOT: obj->pltgot = (Elf_Addr *)(obj->relocbase + dynp->d_un.d_ptr); break; case DT_TEXTREL: obj->textrel = true; break; case DT_SYMBOLIC: obj->symbolic = true; break; case DT_RPATH: /* * We have to wait until later to process this, because * we might not have gotten the address of the string * table yet. */ *dyn_rpath = dynp; break; case DT_SONAME: *dyn_soname = dynp; break; case DT_RUNPATH: *dyn_runpath = dynp; break; case DT_INIT: obj->init = (uintptr_t)(obj->relocbase + dynp->d_un.d_ptr); break; case DT_PREINIT_ARRAY: obj->preinit_array = (uintptr_t *)(obj->relocbase + dynp->d_un.d_ptr); break; case DT_PREINIT_ARRAYSZ: obj->preinit_array_num = dynp->d_un.d_val / sizeof(uintptr_t); break; case DT_INIT_ARRAY: obj->init_array = (uintptr_t *)(obj->relocbase + dynp->d_un.d_ptr); break; case DT_INIT_ARRAYSZ: obj->init_array_num = dynp->d_un.d_val / sizeof(uintptr_t); break; case DT_FINI: obj->fini = (uintptr_t)(obj->relocbase + dynp->d_un.d_ptr); break; case DT_FINI_ARRAY: obj->fini_array = (uintptr_t *)(obj->relocbase + dynp->d_un.d_ptr); break; case DT_FINI_ARRAYSZ: obj->fini_array_num = dynp->d_un.d_val / sizeof(uintptr_t); break; case DT_DEBUG: if (!early) dbg("Filling in DT_DEBUG entry"); (__DECONST(Elf_Dyn *, dynp))->d_un.d_ptr = (Elf_Addr)&r_debug; break; case DT_FLAGS: if (dynp->d_un.d_val & DF_ORIGIN) obj->z_origin = true; if (dynp->d_un.d_val & DF_SYMBOLIC) obj->symbolic = true; if (dynp->d_un.d_val & DF_TEXTREL) obj->textrel = true; if (dynp->d_un.d_val & DF_BIND_NOW) obj->bind_now = true; if (dynp->d_un.d_val & DF_STATIC_TLS) obj->static_tls = true; break; case DT_FLAGS_1: if (dynp->d_un.d_val & DF_1_NOOPEN) obj->z_noopen = true; if (dynp->d_un.d_val & DF_1_ORIGIN) obj->z_origin = true; if (dynp->d_un.d_val & DF_1_GLOBAL) obj->z_global = true; if (dynp->d_un.d_val & DF_1_BIND_NOW) obj->bind_now = true; if (dynp->d_un.d_val & DF_1_NODELETE) obj->z_nodelete = true; if (dynp->d_un.d_val & DF_1_LOADFLTR) obj->z_loadfltr = true; if (dynp->d_un.d_val & DF_1_INTERPOSE) obj->z_interpose = true; if (dynp->d_un.d_val & DF_1_NODEFLIB) obj->z_nodeflib = true; if (dynp->d_un.d_val & DF_1_PIE) obj->z_pie = true; if (dynp->d_un.d_val & DF_1_INITFIRST) obj->z_initfirst = true; break; default: if (arch_digest_dynamic(obj, dynp)) break; if (!early) { dbg("Ignoring d_tag %ld = %#lx", (long)dynp->d_tag, (long)dynp->d_tag); } break; } } obj->traced = false; if (plttype == DT_RELA) { obj->pltrela = (const Elf_Rela *)obj->pltrel; obj->pltrel = NULL; obj->pltrelasize = obj->pltrelsize; obj->pltrelsize = 0; } /* Determine size of dynsym table (equal to nchains of sysv hash) */ if (obj->valid_hash_sysv) obj->dynsymcount = obj->nchains; else if (obj->valid_hash_gnu) { obj->dynsymcount = 0; for (bkt = 0; bkt < obj->nbuckets_gnu; bkt++) { if (obj->buckets_gnu[bkt] == 0) continue; hashval = &obj->chain_zero_gnu[obj->buckets_gnu[bkt]]; do obj->dynsymcount++; while ((*hashval++ & 1u) == 0); } obj->dynsymcount += obj->symndx_gnu; } if (obj->linkmap.l_refname != NULL) obj->linkmap.l_refname = obj->strtab + (unsigned long)obj->linkmap.l_refname; } static bool obj_resolve_origin(Obj_Entry *obj) { if (obj->origin_path != NULL) return (true); obj->origin_path = xmalloc(PATH_MAX); return (rtld_dirname_abs(obj->path, obj->origin_path) != -1); } static bool digest_dynamic2(Obj_Entry *obj, const Elf_Dyn *dyn_rpath, const Elf_Dyn *dyn_soname, const Elf_Dyn *dyn_runpath) { if (obj->z_origin && !obj_resolve_origin(obj)) return (false); if (dyn_runpath != NULL) { obj->runpath = (const char *)obj->strtab + dyn_runpath->d_un.d_val; obj->runpath = origin_subst(obj, obj->runpath); } else if (dyn_rpath != NULL) { obj->rpath = (const char *)obj->strtab + dyn_rpath->d_un.d_val; obj->rpath = origin_subst(obj, obj->rpath); } if (dyn_soname != NULL) object_add_name(obj, obj->strtab + dyn_soname->d_un.d_val); return (true); } static bool digest_dynamic(Obj_Entry *obj, int early) { const Elf_Dyn *dyn_rpath; const Elf_Dyn *dyn_soname; const Elf_Dyn *dyn_runpath; digest_dynamic1(obj, early, &dyn_rpath, &dyn_soname, &dyn_runpath); return (digest_dynamic2(obj, dyn_rpath, dyn_soname, dyn_runpath)); } /* * Process a shared object's program header. This is used only for the * main program, when the kernel has already loaded the main program * into memory before calling the dynamic linker. It creates and * returns an Obj_Entry structure. */ static Obj_Entry * digest_phdr(const Elf_Phdr *phdr, int phnum, caddr_t entry, const char *path) { Obj_Entry *obj; const Elf_Phdr *phlimit = phdr + phnum; const Elf_Phdr *ph; Elf_Addr note_start, note_end; int nsegs = 0; obj = obj_new(); for (ph = phdr; ph < phlimit; ph++) { if (ph->p_type != PT_PHDR) continue; obj->phdr = phdr; obj->phnum = ph->p_memsz / sizeof(*ph); obj->relocbase = __DECONST(char *, phdr) - ph->p_vaddr; break; } obj->stack_flags = PF_X | PF_R | PF_W; for (ph = phdr; ph < phlimit; ph++) { switch (ph->p_type) { case PT_INTERP: obj->interp = (const char *)(ph->p_vaddr + obj->relocbase); break; case PT_LOAD: if (nsegs == 0) { /* First load segment */ obj->vaddrbase = rtld_trunc_page(ph->p_vaddr); obj->mapbase = obj->vaddrbase + obj->relocbase; } else { /* Last load segment */ obj->mapsize = rtld_round_page( ph->p_vaddr + ph->p_memsz) - obj->vaddrbase; } nsegs++; break; case PT_DYNAMIC: obj->dynamic = (const Elf_Dyn *)(ph->p_vaddr + obj->relocbase); break; case PT_TLS: obj->tlsindex = 1; obj->tlssize = ph->p_memsz; obj->tlsalign = ph->p_align; obj->tlsinitsize = ph->p_filesz; obj->tlsinit = (void *)(ph->p_vaddr + obj->relocbase); obj->tlspoffset = ph->p_offset; break; case PT_GNU_STACK: obj->stack_flags = ph->p_flags; break; case PT_NOTE: note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; note_end = note_start + ph->p_filesz; digest_notes(obj, note_start, note_end); break; } } if (nsegs < 1) { _rtld_error("%s: too few PT_LOAD segments", path); return (NULL); } obj->entry = entry; return (obj); } void digest_notes(Obj_Entry *obj, Elf_Addr note_start, Elf_Addr note_end) { const Elf_Note *note; const char *note_name; uintptr_t p; for (note = (const Elf_Note *)note_start; (Elf_Addr)note < note_end; note = (const Elf_Note *)((const char *)(note + 1) + roundup2(note->n_namesz, sizeof(Elf32_Addr)) + roundup2(note->n_descsz, sizeof(Elf32_Addr)))) { if (arch_digest_note(obj, note)) continue; if (note->n_namesz != sizeof(NOTE_FREEBSD_VENDOR) || note->n_descsz != sizeof(int32_t)) continue; if (note->n_type != NT_FREEBSD_ABI_TAG && note->n_type != NT_FREEBSD_FEATURE_CTL && note->n_type != NT_FREEBSD_NOINIT_TAG) continue; note_name = (const char *)(note + 1); if (strncmp(NOTE_FREEBSD_VENDOR, note_name, sizeof(NOTE_FREEBSD_VENDOR)) != 0) continue; switch (note->n_type) { case NT_FREEBSD_ABI_TAG: /* FreeBSD osrel note */ p = (uintptr_t)(note + 1); p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); obj->osrel = *(const int32_t *)(p); dbg("note osrel %d", obj->osrel); break; case NT_FREEBSD_FEATURE_CTL: /* FreeBSD ABI feature control note */ p = (uintptr_t)(note + 1); p += roundup2(note->n_namesz, sizeof(Elf32_Addr)); obj->fctl0 = *(const uint32_t *)(p); dbg("note fctl0 %#x", obj->fctl0); break; case NT_FREEBSD_NOINIT_TAG: /* FreeBSD 'crt does not call init' note */ obj->crt_no_init = true; dbg("note crt_no_init"); break; } } } static Obj_Entry * dlcheck(void *handle) { Obj_Entry *obj; TAILQ_FOREACH(obj, &obj_list, next) { if (obj == (Obj_Entry *)handle) break; } if (obj == NULL || obj->refcount == 0 || obj->dl_refcount == 0) { _rtld_error("Invalid shared object handle %p", handle); return (NULL); } return (obj); } /* * If the given object is already in the donelist, return true. Otherwise * add the object to the list and return false. */ static bool donelist_check(DoneList *dlp, const Obj_Entry *obj) { unsigned int i; for (i = 0; i < dlp->num_used; i++) if (dlp->objs[i] == obj) return (true); /* * Our donelist allocation should always be sufficient. But if * our threads locking isn't working properly, more shared objects * could have been loaded since we allocated the list. That should * never happen, but we'll handle it properly just in case it does. */ if (dlp->num_used < dlp->num_alloc) dlp->objs[dlp->num_used++] = obj; return (false); } /* * SysV hash function for symbol table lookup. It is a slightly optimized * version of the hash specified by the System V ABI. */ Elf32_Word elf_hash(const char *name) { const unsigned char *p = (const unsigned char *)name; Elf32_Word h = 0; while (*p != '\0') { h = (h << 4) + *p++; h ^= (h >> 24) & 0xf0; } return (h & 0x0fffffff); } /* * The GNU hash function is the Daniel J. Bernstein hash clipped to 32 bits * unsigned in case it's implemented with a wider type. */ static uint32_t gnu_hash(const char *s) { uint32_t h; unsigned char c; h = 5381; for (c = *s; c != '\0'; c = *++s) h = h * 33 + c; return (h & 0xffffffff); } /* * Find the library with the given name, and return its full pathname. * The returned string is dynamically allocated. Generates an error * message and returns NULL if the library cannot be found. * * If the second argument is non-NULL, then it refers to an already- * loaded shared object, whose library search path will be searched. * * If a library is successfully located via LD_LIBRARY_PATH_FDS, its * descriptor (which is close-on-exec) will be passed out via the third * argument. * * The search order is: * DT_RPATH in the referencing file _unless_ DT_RUNPATH is present (1) * DT_RPATH of the main object if DSO without defined DT_RUNPATH (1) * LD_LIBRARY_PATH * DT_RUNPATH in the referencing file * ldconfig hints (if -z nodefaultlib, filter out default library directories * from list) * /lib:/usr/lib _unless_ the referencing file is linked with -z nodefaultlib * * (1) Handled in digest_dynamic2 - rpath left NULL if runpath defined. */ static char * find_library(const char *xname, const Obj_Entry *refobj, int *fdp) { char *pathname, *refobj_path; const char *name; bool nodeflib, objgiven; objgiven = refobj != NULL; if (libmap_disable || !objgiven || (name = lm_find(refobj->path, xname)) == NULL) name = xname; if (strchr(name, '/') != NULL) { /* Hard coded pathname */ if (name[0] != '/' && !trust) { _rtld_error( "Absolute pathname required for shared object \"%s\"", name); return (NULL); } return (origin_subst(__DECONST(Obj_Entry *, refobj), __DECONST(char *, name))); } dbg(" Searching for \"%s\"", name); refobj_path = objgiven ? refobj->path : NULL; /* * If refobj->rpath != NULL, then refobj->runpath is NULL. Fall * back to pre-conforming behaviour if user requested so with * LD_LIBRARY_PATH_RPATH environment variable and ignore -z * nodeflib. */ if (objgiven && refobj->rpath != NULL && ld_library_path_rpath) { pathname = search_library_path(name, ld_library_path, refobj_path, fdp); if (pathname != NULL) return (pathname); if (refobj != NULL) { pathname = search_library_path(name, refobj->rpath, refobj_path, fdp); if (pathname != NULL) return (pathname); } pathname = search_library_pathfds(name, ld_library_dirs, fdp); if (pathname != NULL) return (pathname); pathname = search_library_path(name, gethints(false), refobj_path, fdp); if (pathname != NULL) return (pathname); pathname = search_library_path(name, ld_standard_library_path, refobj_path, fdp); if (pathname != NULL) return (pathname); } else { nodeflib = objgiven ? refobj->z_nodeflib : false; if (objgiven) { pathname = search_library_path(name, refobj->rpath, refobj->path, fdp); if (pathname != NULL) return (pathname); } if (objgiven && refobj->runpath == NULL && refobj != obj_main) { pathname = search_library_path(name, obj_main->rpath, refobj_path, fdp); if (pathname != NULL) return (pathname); } pathname = search_library_path(name, ld_library_path, refobj_path, fdp); if (pathname != NULL) return (pathname); if (objgiven) { pathname = search_library_path(name, refobj->runpath, refobj_path, fdp); if (pathname != NULL) return (pathname); } pathname = search_library_pathfds(name, ld_library_dirs, fdp); if (pathname != NULL) return (pathname); pathname = search_library_path(name, gethints(nodeflib), refobj_path, fdp); if (pathname != NULL) return (pathname); if (objgiven && !nodeflib) { pathname = search_library_path(name, ld_standard_library_path, refobj_path, fdp); if (pathname != NULL) return (pathname); } } if (objgiven && refobj->path != NULL) { _rtld_error( "Shared object \"%s\" not found, required by \"%s\"", name, basename(refobj->path)); } else { _rtld_error("Shared object \"%s\" not found", name); } return (NULL); } /* * Given a symbol number in a referencing object, find the corresponding * definition of the symbol. Returns a pointer to the symbol, or NULL if * no definition was found. Returns a pointer to the Obj_Entry of the * defining object via the reference parameter DEFOBJ_OUT. */ const Elf_Sym * find_symdef(unsigned long symnum, const Obj_Entry *refobj, const Obj_Entry **defobj_out, int flags, SymCache *cache, RtldLockState *lockstate) { const Elf_Sym *ref; const Elf_Sym *def; const Obj_Entry *defobj; const Ver_Entry *ve; SymLook req; const char *name; int res; /* * If we have already found this symbol, get the information from * the cache. */ if (symnum >= refobj->dynsymcount) return (NULL); /* Bad object */ if (cache != NULL && cache[symnum].sym != NULL) { *defobj_out = cache[symnum].obj; return (cache[symnum].sym); } ref = refobj->symtab + symnum; name = refobj->strtab + ref->st_name; def = NULL; defobj = NULL; ve = NULL; /* * We don't have to do a full scale lookup if the symbol is local. * We know it will bind to the instance in this load module; to * which we already have a pointer (ie ref). By not doing a lookup, * we not only improve performance, but it also avoids unresolvable * symbols when local symbols are not in the hash table. This has * been seen with the ia64 toolchain. */ if (ELF_ST_BIND(ref->st_info) != STB_LOCAL) { if (ELF_ST_TYPE(ref->st_info) == STT_SECTION) { _rtld_error("%s: Bogus symbol table entry %lu", refobj->path, symnum); } symlook_init(&req, name); req.flags = flags; ve = req.ventry = fetch_ventry(refobj, symnum); req.lockstate = lockstate; res = symlook_default(&req, refobj); if (res == 0) { def = req.sym_out; defobj = req.defobj_out; } } else { def = ref; defobj = refobj; } /* * If we found no definition and the reference is weak, treat the * symbol as having the value zero. */ if (def == NULL && ELF_ST_BIND(ref->st_info) == STB_WEAK) { def = &sym_zero; defobj = obj_main; } if (def != NULL) { *defobj_out = defobj; /* * Record the information in the cache to avoid subsequent * lookups. */ if (cache != NULL) { cache[symnum].sym = def; cache[symnum].obj = defobj; } } else { if (refobj != &obj_rtld) _rtld_error("%s: Undefined symbol \"%s%s%s\"", refobj->path, name, ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); } return (def); } /* Convert between native byte order and forced little resp. big endian. */ #define COND_SWAP(n) (is_le ? le32toh(n) : be32toh(n)) /* * Return the search path from the ldconfig hints file, reading it if * necessary. If nostdlib is true, then the default search paths are * not added to result. * * Returns NULL if there are problems with the hints file, * or if the search path there is empty. */ static const char * gethints(bool nostdlib) { static char *filtered_path; static const char *hints; static struct elfhints_hdr hdr; struct fill_search_info_args sargs, hargs; struct dl_serinfo smeta, hmeta, *SLPinfo, *hintinfo; struct dl_serpath *SLPpath, *hintpath; char *p; struct stat hint_stat; unsigned int SLPndx, hintndx, fndx, fcount; int fd; size_t flen; uint32_t dl; uint32_t magic; /* Magic number */ uint32_t version; /* File version (1) */ uint32_t strtab; /* Offset of string table in file */ uint32_t dirlist; /* Offset of directory list in string table */ uint32_t dirlistlen; /* strlen(dirlist) */ bool is_le; /* Does the hints file use little endian */ bool skip; /* First call, read the hints file */ if (hints == NULL) { /* Keep from trying again in case the hints file is bad. */ hints = ""; if ((fd = open(ld_elf_hints_path, O_RDONLY | O_CLOEXEC)) == -1) { dbg("failed to open hints file \"%s\"", ld_elf_hints_path); return (NULL); } /* * Check of hdr.dirlistlen value against type limit * intends to pacify static analyzers. Further * paranoia leads to checks that dirlist is fully * contained in the file range. */ if (read(fd, &hdr, sizeof hdr) != sizeof hdr) { dbg("failed to read %lu bytes from hints file \"%s\"", (u_long)sizeof hdr, ld_elf_hints_path); cleanup1: close(fd); hdr.dirlistlen = 0; return (NULL); } dbg("host byte-order: %s-endian", le32toh(1) == 1 ? "little" : "big"); dbg("hints file byte-order: %s-endian", hdr.magic == htole32(ELFHINTS_MAGIC) ? "little" : "big"); is_le = /*htole32(1) == 1 || */ hdr.magic == htole32(ELFHINTS_MAGIC); magic = COND_SWAP(hdr.magic); version = COND_SWAP(hdr.version); strtab = COND_SWAP(hdr.strtab); dirlist = COND_SWAP(hdr.dirlist); dirlistlen = COND_SWAP(hdr.dirlistlen); if (magic != ELFHINTS_MAGIC) { dbg("invalid magic number %#08x (expected: %#08x)", magic, ELFHINTS_MAGIC); goto cleanup1; } if (version != 1) { dbg("hints file version %d (expected: 1)", version); goto cleanup1; } if (dirlistlen > UINT_MAX / 2) { dbg("directory list is to long: %d > %d", dirlistlen, UINT_MAX / 2); goto cleanup1; } if (fstat(fd, &hint_stat) == -1) { dbg("failed to find length of hints file \"%s\"", ld_elf_hints_path); goto cleanup1; } dl = strtab; if (dl + dirlist < dl) { dbg("invalid string table position %d", dl); goto cleanup1; } dl += dirlist; if (dl + dirlistlen < dl) { dbg("invalid directory list offset %d", dirlist); goto cleanup1; } dl += dirlistlen; if (dl > hint_stat.st_size) { dbg("hints file \"%s\" is truncated (%d vs. %jd bytes)", ld_elf_hints_path, dl, (uintmax_t)hint_stat.st_size); goto cleanup1; } p = xmalloc(dirlistlen + 1); if (pread(fd, p, dirlistlen + 1, strtab + dirlist) != (ssize_t)dirlistlen + 1 || p[dirlistlen] != '\0') { free(p); dbg( "failed to read %d bytes starting at %d from hints file \"%s\"", dirlistlen + 1, strtab + dirlist, ld_elf_hints_path); goto cleanup1; } hints = p; close(fd); } /* * If caller agreed to receive list which includes the default * paths, we are done. Otherwise, if we still did not * calculated filtered result, do it now. */ if (!nostdlib) return (hints[0] != '\0' ? hints : NULL); if (filtered_path != NULL) goto filt_ret; /* * Obtain the list of all configured search paths, and the * list of the default paths. * * First estimate the size of the results. */ smeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); smeta.dls_cnt = 0; hmeta.dls_size = __offsetof(struct dl_serinfo, dls_serpath); hmeta.dls_cnt = 0; sargs.request = RTLD_DI_SERINFOSIZE; sargs.serinfo = &smeta; hargs.request = RTLD_DI_SERINFOSIZE; hargs.serinfo = &hmeta; path_enumerate(ld_standard_library_path, fill_search_info, NULL, &sargs); path_enumerate(hints, fill_search_info, NULL, &hargs); SLPinfo = xmalloc(smeta.dls_size); hintinfo = xmalloc(hmeta.dls_size); /* * Next fetch both sets of paths. */ sargs.request = RTLD_DI_SERINFO; sargs.serinfo = SLPinfo; sargs.serpath = &SLPinfo->dls_serpath[0]; sargs.strspace = (char *)&SLPinfo->dls_serpath[smeta.dls_cnt]; hargs.request = RTLD_DI_SERINFO; hargs.serinfo = hintinfo; hargs.serpath = &hintinfo->dls_serpath[0]; hargs.strspace = (char *)&hintinfo->dls_serpath[hmeta.dls_cnt]; path_enumerate(ld_standard_library_path, fill_search_info, NULL, &sargs); path_enumerate(hints, fill_search_info, NULL, &hargs); /* * Now calculate the difference between two sets, by excluding * standard paths from the full set. */ fndx = 0; fcount = 0; filtered_path = xmalloc(dirlistlen + 1); hintpath = &hintinfo->dls_serpath[0]; for (hintndx = 0; hintndx < hmeta.dls_cnt; hintndx++, hintpath++) { skip = false; SLPpath = &SLPinfo->dls_serpath[0]; /* * Check each standard path against current. */ for (SLPndx = 0; SLPndx < smeta.dls_cnt; SLPndx++, SLPpath++) { /* matched, skip the path */ if (!strcmp(hintpath->dls_name, SLPpath->dls_name)) { skip = true; break; } } if (skip) continue; /* * Not matched against any standard path, add the path * to result. Separate consequtive paths with ':'. */ if (fcount > 0) { filtered_path[fndx] = ':'; fndx++; } fcount++; flen = strlen(hintpath->dls_name); strncpy((filtered_path + fndx), hintpath->dls_name, flen); fndx += flen; } filtered_path[fndx] = '\0'; free(SLPinfo); free(hintinfo); filt_ret: return (filtered_path[0] != '\0' ? filtered_path : NULL); } static void init_dag(Obj_Entry *root) { const Needed_Entry *needed; const Objlist_Entry *elm; DoneList donelist; if (root->dag_inited) return; donelist_init(&donelist); /* Root object belongs to own DAG. */ objlist_push_tail(&root->dldags, root); objlist_push_tail(&root->dagmembers, root); donelist_check(&donelist, root); /* * Add dependencies of root object to DAG in breadth order * by exploiting the fact that each new object get added * to the tail of the dagmembers list. */ STAILQ_FOREACH(elm, &root->dagmembers, link) { for (needed = elm->obj->needed; needed != NULL; needed = needed->next) { if (needed->obj == NULL || donelist_check(&donelist, needed->obj)) continue; objlist_push_tail(&needed->obj->dldags, root); objlist_push_tail(&root->dagmembers, needed->obj); } } root->dag_inited = true; } static void init_marker(Obj_Entry *marker) { bzero(marker, sizeof(*marker)); marker->marker = true; } Obj_Entry * globallist_curr(const Obj_Entry *obj) { for (;;) { if (obj == NULL) return (NULL); if (!obj->marker) return (__DECONST(Obj_Entry *, obj)); obj = TAILQ_PREV(obj, obj_entry_q, next); } } Obj_Entry * globallist_next(const Obj_Entry *obj) { for (;;) { obj = TAILQ_NEXT(obj, next); if (obj == NULL) return (NULL); if (!obj->marker) return (__DECONST(Obj_Entry *, obj)); } } /* Prevent the object from being unmapped while the bind lock is dropped. */ static void hold_object(Obj_Entry *obj) { obj->holdcount++; } static void unhold_object(Obj_Entry *obj) { assert(obj->holdcount > 0); if (--obj->holdcount == 0 && obj->unholdfree) release_object(obj); } static void process_z(Obj_Entry *root) { const Objlist_Entry *elm; Obj_Entry *obj; /* * Walk over object DAG and process every dependent object * that is marked as DF_1_NODELETE or DF_1_GLOBAL. They need * to grow their own DAG. * * For DF_1_GLOBAL, DAG is required for symbol lookups in * symlook_global() to work. * * For DF_1_NODELETE, the DAG should have its reference upped. */ STAILQ_FOREACH(elm, &root->dagmembers, link) { obj = elm->obj; if (obj == NULL) continue; if (obj->z_nodelete && !obj->ref_nodel) { dbg("obj %s -z nodelete", obj->path); init_dag(obj); ref_dag(obj); obj->ref_nodel = true; } if (obj->z_global && objlist_find(&list_global, obj) == NULL) { dbg("obj %s -z global", obj->path); objlist_push_tail(&list_global, obj); init_dag(obj); } } } static void parse_rtld_phdr(Obj_Entry *obj) { const Elf_Phdr *ph; Elf_Addr note_start, note_end; bool first_seg; first_seg = true; obj->stack_flags = PF_X | PF_R | PF_W; for (ph = obj->phdr; ph < obj->phdr + obj->phnum; ph++) { switch (ph->p_type) { case PT_LOAD: if (first_seg) { obj->vaddrbase = rtld_trunc_page(ph->p_vaddr); first_seg = false; } obj->mapsize = rtld_round_page(ph->p_vaddr + ph->p_memsz) - obj->vaddrbase; break; case PT_GNU_STACK: obj->stack_flags = ph->p_flags; break; case PT_NOTE: note_start = (Elf_Addr)obj->relocbase + ph->p_vaddr; note_end = note_start + ph->p_filesz; digest_notes(obj, note_start, note_end); break; } } } /* * Initialize the dynamic linker. The argument is the address at which * the dynamic linker has been mapped into memory. The primary task of * this function is to relocate the dynamic linker. */ static void init_rtld(caddr_t mapbase, Elf_Auxinfo **aux_info) { Obj_Entry objtmp; /* Temporary rtld object */ const Elf_Ehdr *ehdr; const Elf_Dyn *dyn_rpath; const Elf_Dyn *dyn_soname; const Elf_Dyn *dyn_runpath; /* * Conjure up an Obj_Entry structure for the dynamic linker. * * The "path" member can't be initialized yet because string constants * cannot yet be accessed. Below we will set it correctly. */ memset(&objtmp, 0, sizeof(objtmp)); objtmp.path = NULL; objtmp.rtld = true; objtmp.mapbase = mapbase; #ifdef PIC objtmp.relocbase = mapbase; #endif objtmp.dynamic = rtld_dynamic(&objtmp); digest_dynamic1(&objtmp, 1, &dyn_rpath, &dyn_soname, &dyn_runpath); assert(objtmp.needed == NULL); assert(!objtmp.textrel); /* * Temporarily put the dynamic linker entry into the object list, so * that symbols can be found. */ relocate_objects(&objtmp, true, &objtmp, 0, NULL); ehdr = (Elf_Ehdr *)mapbase; objtmp.phdr = (Elf_Phdr *)((char *)mapbase + ehdr->e_phoff); objtmp.phnum = ehdr->e_phnum; /* Initialize the object list. */ TAILQ_INIT(&obj_list); /* Now that non-local variables can be accesses, copy out obj_rtld. */ memcpy(&obj_rtld, &objtmp, sizeof(obj_rtld)); /* The page size is required by the dynamic memory allocator. */ init_pagesizes(aux_info); if (aux_info[AT_OSRELDATE] != NULL) osreldate = aux_info[AT_OSRELDATE]->a_un.a_val; digest_dynamic2(&obj_rtld, dyn_rpath, dyn_soname, dyn_runpath); /* Replace the path with a dynamically allocated copy. */ obj_rtld.path = xstrdup(ld_path_rtld); parse_rtld_phdr(&obj_rtld); if (obj_enforce_relro(&obj_rtld) == -1) rtld_die(); r_debug.r_version = R_DEBUG_VERSION; r_debug.r_brk = r_debug_state; r_debug.r_state = RT_CONSISTENT; r_debug.r_ldbase = obj_rtld.relocbase; } /* * Retrieve the array of supported page sizes. The kernel provides the page * sizes in increasing order. */ static void init_pagesizes(Elf_Auxinfo **aux_info) { static size_t psa[MAXPAGESIZES]; int mib[2]; size_t len, size; if (aux_info[AT_PAGESIZES] != NULL && aux_info[AT_PAGESIZESLEN] != NULL) { size = aux_info[AT_PAGESIZESLEN]->a_un.a_val; pagesizes = aux_info[AT_PAGESIZES]->a_un.a_ptr; } else { len = 2; if (sysctlnametomib("hw.pagesizes", mib, &len) == 0) size = sizeof(psa); else { /* As a fallback, retrieve the base page size. */ size = sizeof(psa[0]); if (aux_info[AT_PAGESZ] != NULL) { psa[0] = aux_info[AT_PAGESZ]->a_un.a_val; goto psa_filled; } else { mib[0] = CTL_HW; mib[1] = HW_PAGESIZE; len = 2; } } if (sysctl(mib, len, psa, &size, NULL, 0) == -1) { _rtld_error("sysctl for hw.pagesize(s) failed"); rtld_die(); } psa_filled: pagesizes = psa; } npagesizes = size / sizeof(pagesizes[0]); /* Discard any invalid entries at the end of the array. */ while (npagesizes > 0 && pagesizes[npagesizes - 1] == 0) npagesizes--; page_size = pagesizes[0]; } /* * Add the init functions from a needed object list (and its recursive * needed objects) to "list". This is not used directly; it is a helper * function for initlist_add_objects(). The write lock must be held * when this function is called. */ static void initlist_add_neededs(Needed_Entry *needed, Objlist *list, Objlist *iflist) { /* Recursively process the successor needed objects. */ if (needed->next != NULL) initlist_add_neededs(needed->next, list, iflist); /* Process the current needed object. */ if (needed->obj != NULL) initlist_add_objects(needed->obj, needed->obj, list, iflist); } /* * Scan all of the DAGs rooted in the range of objects from "obj" to * "tail" and add their init functions to "list". This recurses over * the DAGs and ensure the proper init ordering such that each object's * needed libraries are initialized before the object itself. At the * same time, this function adds the objects to the global finalization * list "list_fini" in the opposite order. The write lock must be * held when this function is called. */ static void initlist_for_loaded_obj(Obj_Entry *obj, Obj_Entry *tail, Objlist *list) { Objlist iflist; /* initfirst objs and their needed */ Objlist_Entry *tmp; objlist_init(&iflist); initlist_add_objects(obj, tail, list, &iflist); STAILQ_FOREACH(tmp, &iflist, link) { Obj_Entry *tobj = tmp->obj; if ((tobj->fini != 0 || tobj->fini_array != NULL) && !tobj->on_fini_list) { objlist_push_tail(&list_fini, tobj); tobj->on_fini_list = true; } } /* * This might result in the same object appearing more * than once on the init list. objlist_call_init() * uses obj->init_scanned to avoid dup calls. */ STAILQ_REVERSE(&iflist, Struct_Objlist_Entry, link); STAILQ_FOREACH(tmp, &iflist, link) objlist_push_head(list, tmp->obj); objlist_clear(&iflist); } static void initlist_add_objects(Obj_Entry *obj, Obj_Entry *tail, Objlist *list, Objlist *iflist) { Obj_Entry *nobj; if (obj->init_done) return; if (obj->z_initfirst || list == NULL) { /* * Ignore obj->init_scanned. The object might indeed * already be on the init list, but due to being * needed by an initfirst object, we must put it at * the head of the init list. obj->init_done protects * against double-initialization. */ if (obj->needed != NULL) initlist_add_neededs(obj->needed, NULL, iflist); if (obj->needed_filtees != NULL) initlist_add_neededs(obj->needed_filtees, NULL, iflist); if (obj->needed_aux_filtees != NULL) initlist_add_neededs(obj->needed_aux_filtees, NULL, iflist); objlist_push_tail(iflist, obj); /* Recursively process the successor objects. */ nobj = globallist_next(obj); if (nobj != NULL && obj != tail) initlist_add_objects(nobj, tail, list, iflist); } else { if (obj->init_scanned) return; obj->init_scanned = true; /* Recursively process the successor objects. */ nobj = globallist_next(obj); if (nobj != NULL && obj != tail) initlist_add_objects(nobj, tail, list, iflist); /* Recursively process the needed objects. */ if (obj->needed != NULL) initlist_add_neededs(obj->needed, list, iflist); if (obj->needed_filtees != NULL) initlist_add_neededs(obj->needed_filtees, list, iflist); if (obj->needed_aux_filtees != NULL) initlist_add_neededs(obj->needed_aux_filtees, list, iflist); /* Add the object to the init list. */ objlist_push_tail(list, obj); /* * Add the object to the global fini list in the * reverse order. */ if ((obj->fini != 0 || obj->fini_array != NULL) && !obj->on_fini_list) { objlist_push_head(&list_fini, obj); obj->on_fini_list = true; } } } static void free_needed_filtees(Needed_Entry *n, RtldLockState *lockstate) { Needed_Entry *needed, *needed1; for (needed = n; needed != NULL; needed = needed->next) { if (needed->obj != NULL) { dlclose_locked(needed->obj, lockstate); needed->obj = NULL; } } for (needed = n; needed != NULL; needed = needed1) { needed1 = needed->next; free(needed); } } static void unload_filtees(Obj_Entry *obj, RtldLockState *lockstate) { free_needed_filtees(obj->needed_filtees, lockstate); obj->needed_filtees = NULL; free_needed_filtees(obj->needed_aux_filtees, lockstate); obj->needed_aux_filtees = NULL; obj->filtees_loaded = false; } static void load_filtee1(Obj_Entry *obj, Needed_Entry *needed, int flags, RtldLockState *lockstate) { for (; needed != NULL; needed = needed->next) { needed->obj = dlopen_object(obj->strtab + needed->name, -1, obj, flags, ((ld_loadfltr || obj->z_loadfltr) ? RTLD_NOW : RTLD_LAZY) | RTLD_LOCAL, lockstate); } } static void load_filtees(Obj_Entry *obj, int flags, RtldLockState *lockstate) { if (obj->filtees_loaded || obj->filtees_loading) return; lock_restart_for_upgrade(lockstate); obj->filtees_loading = true; load_filtee1(obj, obj->needed_filtees, flags, lockstate); load_filtee1(obj, obj->needed_aux_filtees, flags, lockstate); obj->filtees_loaded = true; obj->filtees_loading = false; } static int process_needed(Obj_Entry *obj, Needed_Entry *needed, int flags) { Obj_Entry *obj1; for (; needed != NULL; needed = needed->next) { obj1 = needed->obj = load_object(obj->strtab + needed->name, -1, obj, flags & ~RTLD_LO_NOLOAD); if (obj1 == NULL && !ld_tracing && (flags & RTLD_LO_FILTEES) == 0) return (-1); } return (0); } /* * Given a shared object, traverse its list of needed objects, and load * each of them. Returns 0 on success. Generates an error message and * returns -1 on failure. */ static int load_needed_objects(Obj_Entry *first, int flags) { Obj_Entry *obj; for (obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { if (obj->marker) continue; if (process_needed(obj, obj->needed, flags) == -1) return (-1); } return (0); } static int load_preload_objects(const char *penv, bool isfd) { Obj_Entry *obj; const char *name; size_t len; char savech, *p, *psave; int fd; static const char delim[] = " \t:;"; if (penv == NULL) return (0); p = psave = xstrdup(penv); p += strspn(p, delim); while (*p != '\0') { len = strcspn(p, delim); savech = p[len]; p[len] = '\0'; if (isfd) { name = NULL; fd = parse_integer(p); if (fd == -1) { free(psave); return (-1); } } else { name = p; fd = -1; } obj = load_object(name, fd, NULL, 0); if (obj == NULL) { free(psave); return (-1); /* XXX - cleanup */ } obj->z_interpose = true; p[len] = savech; p += len; p += strspn(p, delim); } LD_UTRACE(UTRACE_PRELOAD_FINISHED, NULL, NULL, 0, 0, NULL); free(psave); return (0); } static const char * printable_path(const char *path) { return (path == NULL ? "" : path); } /* * Load a shared object into memory, if it is not already loaded. The * object may be specified by name or by user-supplied file descriptor * fd_u. In the later case, the fd_u descriptor is not closed, but its * duplicate is. * * Returns a pointer to the Obj_Entry for the object. Returns NULL * on failure. */ static Obj_Entry * load_object(const char *name, int fd_u, const Obj_Entry *refobj, int flags) { Obj_Entry *obj; int fd; struct stat sb; char *path; fd = -1; if (name != NULL) { TAILQ_FOREACH(obj, &obj_list, next) { if (obj->marker || obj->doomed) continue; if (object_match_name(obj, name)) return (obj); } path = find_library(name, refobj, &fd); if (path == NULL) return (NULL); } else path = NULL; if (fd >= 0) { /* * search_library_pathfds() opens a fresh file descriptor for * the library, so there is no need to dup(). */ } else if (fd_u == -1) { /* * If we didn't find a match by pathname, or the name is not * supplied, open the file and check again by device and inode. * This avoids false mismatches caused by multiple links or ".." * in pathnames. * * To avoid a race, we open the file and use fstat() rather than * using stat(). */ if ((fd = open(path, O_RDONLY | O_CLOEXEC | O_VERIFY)) == -1) { fd = try_fds_open(path, ld_library_dirs); if (fd == -1) { _rtld_error("Cannot open \"%s\"", path); free(path); return (NULL); } } } else { fd = fcntl(fd_u, F_DUPFD_CLOEXEC, 0); if (fd == -1) { _rtld_error("Cannot dup fd"); free(path); return (NULL); } } if (fstat(fd, &sb) == -1) { _rtld_error("Cannot fstat \"%s\"", printable_path(path)); close(fd); free(path); return (NULL); } TAILQ_FOREACH(obj, &obj_list, next) { if (obj->marker || obj->doomed) continue; if (obj->ino == sb.st_ino && obj->dev == sb.st_dev) break; } if (obj != NULL) { if (name != NULL) object_add_name(obj, name); free(path); close(fd); return (obj); } if (flags & RTLD_LO_NOLOAD) { free(path); close(fd); return (NULL); } /* First use of this object, so we must map it in */ obj = do_load_object(fd, name, path, &sb, flags); if (obj == NULL) free(path); close(fd); return (obj); } static Obj_Entry * do_load_object(int fd, const char *name, char *path, struct stat *sbp, int flags) { Obj_Entry *obj; struct statfs fs; /* * First, make sure that environment variables haven't been * used to circumvent the noexec flag on a filesystem. * We ignore fstatfs(2) failures, since fd might reference * not a file, e.g. shmfd. */ if (dangerous_ld_env && fstatfs(fd, &fs) == 0 && (fs.f_flags & MNT_NOEXEC) != 0) { _rtld_error("Cannot execute objects on %s", fs.f_mntonname); return (NULL); } dbg("loading \"%s\"", printable_path(path)); obj = map_object(fd, printable_path(path), sbp, false); if (obj == NULL) return (NULL); /* * If DT_SONAME is present in the object, digest_dynamic2 already * added it to the object names. */ if (name != NULL) object_add_name(obj, name); obj->path = path; if (!digest_dynamic(obj, 0)) goto errp; dbg("%s valid_hash_sysv %d valid_hash_gnu %d dynsymcount %d", obj->path, obj->valid_hash_sysv, obj->valid_hash_gnu, obj->dynsymcount); if (obj->z_pie && (flags & RTLD_LO_TRACE) == 0) { dbg("refusing to load PIE executable \"%s\"", obj->path); _rtld_error("Cannot load PIE binary %s as DSO", obj->path); goto errp; } if (obj->z_noopen && (flags & (RTLD_LO_DLOPEN | RTLD_LO_TRACE)) == RTLD_LO_DLOPEN) { dbg("refusing to load non-loadable \"%s\"", obj->path); _rtld_error("Cannot dlopen non-loadable %s", obj->path); goto errp; } obj->dlopened = (flags & RTLD_LO_DLOPEN) != 0; TAILQ_INSERT_TAIL(&obj_list, obj, next); obj_count++; obj_loads++; linkmap_add(obj); /* for GDB & dlinfo() */ max_stack_flags |= obj->stack_flags; dbg(" %p .. %p: %s", obj->mapbase, obj->mapbase + obj->mapsize - 1, obj->path); if (obj->textrel) dbg(" WARNING: %s has impure text", obj->path); LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, obj->path); return (obj); errp: munmap(obj->mapbase, obj->mapsize); obj_free(obj); return (NULL); } static int load_kpreload(const void *addr) { Obj_Entry *obj; const Elf_Ehdr *ehdr; const Elf_Phdr *phdr, *phlimit, *phdyn, *seg0, *segn; static const char kname[] = "[vdso]"; ehdr = addr; if (!check_elf_headers(ehdr, "kpreload")) return (-1); obj = obj_new(); phdr = (const Elf_Phdr *)((const char *)addr + ehdr->e_phoff); obj->phdr = phdr; obj->phnum = ehdr->e_phnum; phlimit = phdr + ehdr->e_phnum; seg0 = segn = NULL; for (; phdr < phlimit; phdr++) { switch (phdr->p_type) { case PT_DYNAMIC: phdyn = phdr; break; case PT_GNU_STACK: /* Absense of PT_GNU_STACK implies stack_flags == 0. */ obj->stack_flags = phdr->p_flags; break; case PT_LOAD: if (seg0 == NULL || seg0->p_vaddr > phdr->p_vaddr) seg0 = phdr; if (segn == NULL || segn->p_vaddr + segn->p_memsz < phdr->p_vaddr + phdr->p_memsz) segn = phdr; break; } } obj->mapbase = __DECONST(caddr_t, addr); obj->mapsize = segn->p_vaddr + segn->p_memsz; obj->vaddrbase = 0; obj->relocbase = obj->mapbase; object_add_name(obj, kname); obj->path = xstrdup(kname); obj->dynamic = (const Elf_Dyn *)(obj->relocbase + phdyn->p_vaddr); if (!digest_dynamic(obj, 0)) { obj_free(obj); return (-1); } /* * We assume that kernel-preloaded object does not need * relocation. It is currently written into read-only page, * handling relocations would mean we need to allocate at * least one additional page per AS. */ dbg("%s mapbase %p phdrs %p PT_LOAD phdr %p vaddr %p dynamic %p", obj->path, obj->mapbase, obj->phdr, seg0, obj->relocbase + seg0->p_vaddr, obj->dynamic); TAILQ_INSERT_TAIL(&obj_list, obj, next); obj_count++; obj_loads++; linkmap_add(obj); /* for GDB & dlinfo() */ max_stack_flags |= obj->stack_flags; LD_UTRACE(UTRACE_LOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, obj->path); return (0); } Obj_Entry * obj_from_addr(const void *addr) { Obj_Entry *obj; TAILQ_FOREACH(obj, &obj_list, next) { if (obj->marker) continue; if (addr < (void *)obj->mapbase) continue; if (addr < (void *)(obj->mapbase + obj->mapsize)) return obj; } return (NULL); } static void preinit_main(void) { uintptr_t *preinit_addr; int index; preinit_addr = obj_main->preinit_array; if (preinit_addr == NULL) return; for (index = 0; index < obj_main->preinit_array_num; index++) { if (preinit_addr[index] != 0 && preinit_addr[index] != 1) { dbg("calling preinit function for %s at %p", obj_main->path, (void *)preinit_addr[index]); LD_UTRACE(UTRACE_INIT_CALL, obj_main, (void *)preinit_addr[index], 0, 0, obj_main->path); call_init_pointer(obj_main, preinit_addr[index]); } } } /* * Call the finalization functions for each of the objects in "list" * belonging to the DAG of "root" and referenced once. If NULL "root" * is specified, every finalization function will be called regardless * of the reference count and the list elements won't be freed. All of * the objects are expected to have non-NULL fini functions. */ static void objlist_call_fini(Objlist *list, Obj_Entry *root, RtldLockState *lockstate) { Objlist_Entry *elm; struct dlerror_save *saved_msg; uintptr_t *fini_addr; int index; assert(root == NULL || root->refcount == 1); if (root != NULL) root->doomed = true; /* * Preserve the current error message since a fini function might * call into the dynamic linker and overwrite it. */ saved_msg = errmsg_save(); do { STAILQ_FOREACH(elm, list, link) { if (root != NULL && (elm->obj->refcount != 1 || objlist_find(&root->dagmembers, elm->obj) == NULL)) continue; /* Remove object from fini list to prevent recursive * invocation. */ STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); /* Ensure that new references cannot be acquired. */ elm->obj->doomed = true; hold_object(elm->obj); lock_release(rtld_bind_lock, lockstate); /* * It is legal to have both DT_FINI and DT_FINI_ARRAY * defined. When this happens, DT_FINI_ARRAY is * processed first. */ fini_addr = elm->obj->fini_array; if (fini_addr != NULL && elm->obj->fini_array_num > 0) { for (index = elm->obj->fini_array_num - 1; index >= 0; index--) { if (fini_addr[index] != 0 && fini_addr[index] != 1) { dbg("calling fini function for %s at %p", elm->obj->path, (void *)fini_addr[index]); LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)fini_addr[index], 0, 0, elm->obj->path); call_initfini_pointer(elm->obj, fini_addr[index]); } } } if (elm->obj->fini != 0) { dbg("calling fini function for %s at %p", elm->obj->path, (void *)elm->obj->fini); LD_UTRACE(UTRACE_FINI_CALL, elm->obj, (void *)elm->obj->fini, 0, 0, elm->obj->path); call_initfini_pointer(elm->obj, elm->obj->fini); } wlock_acquire(rtld_bind_lock, lockstate); unhold_object(elm->obj); /* No need to free anything if process is going down. */ if (root != NULL) free(elm); /* * We must restart the list traversal after every fini * call because a dlclose() call from the fini function * or from another thread might have modified the * reference counts. */ break; } } while (elm != NULL); errmsg_restore(saved_msg); } /* * Call the initialization functions for each of the objects in * "list". All of the objects are expected to have non-NULL init * functions. */ static void objlist_call_init(Objlist *list, RtldLockState *lockstate) { Objlist_Entry *elm; Obj_Entry *obj; struct dlerror_save *saved_msg; uintptr_t *init_addr; void (*reg)(void (*)(void)); int index; /* * Clean init_scanned flag so that objects can be rechecked and * possibly initialized earlier if any of vectors called below * cause the change by using dlopen. */ TAILQ_FOREACH(obj, &obj_list, next) { if (obj->marker) continue; obj->init_scanned = false; } /* * Preserve the current error message since an init function might * call into the dynamic linker and overwrite it. */ saved_msg = errmsg_save(); STAILQ_FOREACH(elm, list, link) { if (elm->obj->init_done) /* Initialized early. */ continue; /* * Race: other thread might try to use this object before * current one completes the initialization. Not much can be * done here without better locking. */ elm->obj->init_done = true; hold_object(elm->obj); reg = NULL; if (elm->obj == obj_main && obj_main->crt_no_init) { reg = (void (*)(void (*)(void))) get_program_var_addr("__libc_atexit", lockstate); } lock_release(rtld_bind_lock, lockstate); if (reg != NULL) { reg(rtld_exit); rtld_exit_ptr = rtld_nop_exit; } /* * It is legal to have both DT_INIT and DT_INIT_ARRAY defined. * When this happens, DT_INIT is processed first. */ if (elm->obj->init != 0) { dbg("calling init function for %s at %p", elm->obj->path, (void *)elm->obj->init); LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)elm->obj->init, 0, 0, elm->obj->path); call_init_pointer(elm->obj, elm->obj->init); } init_addr = elm->obj->init_array; if (init_addr != NULL) { for (index = 0; index < elm->obj->init_array_num; index++) { if (init_addr[index] != 0 && init_addr[index] != 1) { dbg("calling init function for %s at %p", elm->obj->path, (void *)init_addr[index]); LD_UTRACE(UTRACE_INIT_CALL, elm->obj, (void *)init_addr[index], 0, 0, elm->obj->path); call_init_pointer(elm->obj, init_addr[index]); } } } wlock_acquire(rtld_bind_lock, lockstate); unhold_object(elm->obj); } errmsg_restore(saved_msg); } static void objlist_clear(Objlist *list) { Objlist_Entry *elm; while (!STAILQ_EMPTY(list)) { elm = STAILQ_FIRST(list); STAILQ_REMOVE_HEAD(list, link); free(elm); } } static Objlist_Entry * objlist_find(Objlist *list, const Obj_Entry *obj) { Objlist_Entry *elm; STAILQ_FOREACH(elm, list, link) if (elm->obj == obj) return elm; return (NULL); } static void objlist_init(Objlist *list) { STAILQ_INIT(list); } static void objlist_push_head(Objlist *list, Obj_Entry *obj) { Objlist_Entry *elm; elm = NEW(Objlist_Entry); elm->obj = obj; STAILQ_INSERT_HEAD(list, elm, link); } static void objlist_push_tail(Objlist *list, Obj_Entry *obj) { Objlist_Entry *elm; elm = NEW(Objlist_Entry); elm->obj = obj; STAILQ_INSERT_TAIL(list, elm, link); } static void objlist_put_after(Objlist *list, Obj_Entry *listobj, Obj_Entry *obj) { Objlist_Entry *elm, *listelm; STAILQ_FOREACH(listelm, list, link) { if (listelm->obj == listobj) break; } elm = NEW(Objlist_Entry); elm->obj = obj; if (listelm != NULL) STAILQ_INSERT_AFTER(list, listelm, elm, link); else STAILQ_INSERT_TAIL(list, elm, link); } static void objlist_remove(Objlist *list, Obj_Entry *obj) { Objlist_Entry *elm; if ((elm = objlist_find(list, obj)) != NULL) { STAILQ_REMOVE(list, elm, Struct_Objlist_Entry, link); free(elm); } } /* * Relocate dag rooted in the specified object. * Returns 0 on success, or -1 on failure. */ static int relocate_object_dag(Obj_Entry *root, bool bind_now, Obj_Entry *rtldobj, int flags, RtldLockState *lockstate) { Objlist_Entry *elm; int error; error = 0; STAILQ_FOREACH(elm, &root->dagmembers, link) { error = relocate_object(elm->obj, bind_now, rtldobj, flags, lockstate); if (error == -1) break; } return (error); } /* * Prepare for, or clean after, relocating an object marked with * DT_TEXTREL or DF_TEXTREL. Before relocating, all read-only * segments are remapped read-write. After relocations are done, the * segment's permissions are returned back to the modes specified in * the phdrs. If any relocation happened, or always for wired * program, COW is triggered. */ static int reloc_textrel_prot(Obj_Entry *obj, bool before) { const Elf_Phdr *ph; void *base; size_t sz; int prot; for (ph = obj->phdr; ph < obj->phdr + obj->phnum; ph++) { if (ph->p_type != PT_LOAD || (ph->p_flags & PF_W) != 0) continue; base = obj->relocbase + rtld_trunc_page(ph->p_vaddr); sz = rtld_round_page(ph->p_vaddr + ph->p_filesz) - rtld_trunc_page(ph->p_vaddr); prot = before ? (PROT_READ | PROT_WRITE) : convert_prot(ph->p_flags); if (mprotect(base, sz, prot) == -1) { _rtld_error("%s: Cannot write-%sable text segment: %s", obj->path, before ? "en" : "dis", rtld_strerror(errno)); return (-1); } } return (0); } /* Process RELR relative relocations. */ static void reloc_relr(Obj_Entry *obj) { const Elf_Relr *relr, *relrlim; Elf_Addr *where; relrlim = (const Elf_Relr *)((const char *)obj->relr + obj->relrsize); for (relr = obj->relr; relr < relrlim; relr++) { Elf_Relr entry = *relr; if ((entry & 1) == 0) { where = (Elf_Addr *)(obj->relocbase + entry); *where++ += (Elf_Addr)obj->relocbase; } else { for (long i = 0; (entry >>= 1) != 0; i++) if ((entry & 1) != 0) where[i] += (Elf_Addr)obj->relocbase; where += CHAR_BIT * sizeof(Elf_Relr) - 1; } } } /* * Relocate single object. * Returns 0 on success, or -1 on failure. */ static int relocate_object(Obj_Entry *obj, bool bind_now, Obj_Entry *rtldobj, int flags, RtldLockState *lockstate) { if (obj->relocated) return (0); obj->relocated = true; if (obj != rtldobj) dbg("relocating \"%s\"", obj->path); if (obj->symtab == NULL || obj->strtab == NULL || !(obj->valid_hash_sysv || obj->valid_hash_gnu)) dbg("object %s has no run-time symbol table", obj->path); /* There are relocations to the write-protected text segment. */ if (obj->textrel && reloc_textrel_prot(obj, true) != 0) return (-1); /* Process the non-PLT non-IFUNC relocations. */ if (reloc_non_plt(obj, rtldobj, flags, lockstate)) return (-1); reloc_relr(obj); /* Re-protected the text segment. */ if (obj->textrel && reloc_textrel_prot(obj, false) != 0) return (-1); /* Set the special PLT or GOT entries. */ init_pltgot(obj); /* Process the PLT relocations. */ if (reloc_plt(obj, flags, lockstate) == -1) return (-1); /* Relocate the jump slots if we are doing immediate binding. */ if ((obj->bind_now || bind_now) && reloc_jmpslots(obj, flags, lockstate) == -1) return (-1); if (obj != rtldobj && !obj->mainprog && obj_enforce_relro(obj) == -1) return (-1); /* * Set up the magic number and version in the Obj_Entry. These * were checked in the crt1.o from the original ElfKit, so we * set them for backward compatibility. */ obj->magic = RTLD_MAGIC; obj->version = RTLD_VERSION; return (0); } /* * Relocate newly-loaded shared objects. The argument is a pointer to * the Obj_Entry for the first such object. All objects from the first * to the end of the list of objects are relocated. Returns 0 on success, * or -1 on failure. */ static int relocate_objects(Obj_Entry *first, bool bind_now, Obj_Entry *rtldobj, int flags, RtldLockState *lockstate) { Obj_Entry *obj; int error; for (error = 0, obj = first; obj != NULL; obj = TAILQ_NEXT(obj, next)) { if (obj->marker) continue; error = relocate_object(obj, bind_now, rtldobj, flags, lockstate); if (error == -1) break; } return (error); } /* * The handling of R_MACHINE_IRELATIVE relocations and jumpslots * referencing STT_GNU_IFUNC symbols is postponed till the other * relocations are done. The indirect functions specified as * ifunc are allowed to call other symbols, so we need to have * objects relocated before asking for resolution from indirects. * * The R_MACHINE_IRELATIVE slots are resolved in greedy fashion, * instead of the usual lazy handling of PLT slots. It is * consistent with how GNU does it. */ static int resolve_object_ifunc(Obj_Entry *obj, bool bind_now, int flags, RtldLockState *lockstate) { if (obj->ifuncs_resolved) return (0); obj->ifuncs_resolved = true; if (!obj->irelative && !obj->irelative_nonplt && !((obj->bind_now || bind_now) && obj->gnu_ifunc) && !obj->non_plt_gnu_ifunc) return (0); if (obj_disable_relro(obj) == -1 || (obj->irelative && reloc_iresolve(obj, lockstate) == -1) || (obj->irelative_nonplt && reloc_iresolve_nonplt(obj, lockstate) == -1) || ((obj->bind_now || bind_now) && obj->gnu_ifunc && reloc_gnu_ifunc(obj, flags, lockstate) == -1) || (obj->non_plt_gnu_ifunc && reloc_non_plt(obj, &obj_rtld, flags | SYMLOOK_IFUNC, lockstate) == -1) || obj_enforce_relro(obj) == -1) return (-1); return (0); } static int initlist_objects_ifunc(Objlist *list, bool bind_now, int flags, RtldLockState *lockstate) { Objlist_Entry *elm; Obj_Entry *obj; STAILQ_FOREACH(elm, list, link) { obj = elm->obj; if (obj->marker) continue; if (resolve_object_ifunc(obj, bind_now, flags, lockstate) == -1) return (-1); } return (0); } /* * Cleanup procedure. It will be called (by the atexit mechanism) just * before the process exits. */ static void rtld_exit(void) { RtldLockState lockstate; wlock_acquire(rtld_bind_lock, &lockstate); dbg("rtld_exit()"); objlist_call_fini(&list_fini, NULL, &lockstate); /* No need to remove the items from the list, since we are exiting. */ if (!libmap_disable) lm_fini(); lock_release(rtld_bind_lock, &lockstate); } static void rtld_nop_exit(void) { } /* * Parse string of the format '#number/name", where number must be a * decimal number of the opened file descriptor listed in * LD_LIBRARY_PATH_FDS. If successful, tries to open dso name under * dirfd number and returns resulting fd. * On any error, returns -1. */ static int try_fds_open(const char *name, const char *path) { const char *n; char *envcopy, *fdstr, *last_token, *ncopy; size_t len; int fd, dirfd, dirfd_path; if (!trust || name[0] != '#' || path == NULL) return (-1); name++; n = strchr(name, '/'); if (n == NULL) return (-1); len = n - name; ncopy = xmalloc(len + 1); memcpy(ncopy, name, len); ncopy[len] = '\0'; dirfd = parse_integer(ncopy); free(ncopy); if (dirfd == -1) return (-1); envcopy = xstrdup(path); dirfd_path = -1; for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; fdstr = strtok_r(NULL, ":", &last_token)) { dirfd_path = parse_integer(fdstr); if (dirfd_path == dirfd) break; } free(envcopy); if (dirfd_path != dirfd) return (-1); fd = __sys_openat(dirfd, n + 1, O_RDONLY | O_CLOEXEC | O_VERIFY); return (fd); } /* * Iterate over a search path, translate each element, and invoke the * callback on the result. */ static void * path_enumerate(const char *path, path_enum_proc callback, const char *refobj_path, void *arg) { const char *trans; if (path == NULL) return (NULL); path += strspn(path, ":;"); while (*path != '\0') { size_t len; char *res; len = strcspn(path, ":;"); trans = lm_findn(refobj_path, path, len); if (trans) res = callback(trans, strlen(trans), arg); else res = callback(path, len, arg); if (res != NULL) return (res); path += len; path += strspn(path, ":;"); } return (NULL); } struct try_library_args { const char *name; size_t namelen; char *buffer; size_t buflen; int fd; }; static void * try_library_path(const char *dir, size_t dirlen, void *param) { struct try_library_args *arg; int fd; arg = param; if (*dir == '/' || trust) { char *pathname; if (dirlen + 1 + arg->namelen + 1 > arg->buflen) return (NULL); pathname = arg->buffer; strncpy(pathname, dir, dirlen); pathname[dirlen] = '/'; strcpy(pathname + dirlen + 1, arg->name); dbg(" Trying \"%s\"", pathname); fd = open(pathname, O_RDONLY | O_CLOEXEC | O_VERIFY); if (fd >= 0) { dbg(" Opened \"%s\", fd %d", pathname, fd); pathname = xmalloc(dirlen + 1 + arg->namelen + 1); strcpy(pathname, arg->buffer); arg->fd = fd; return (pathname); } else { dbg(" Failed to open \"%s\": %s", pathname, rtld_strerror(errno)); } } return (NULL); } static char * search_library_path(const char *name, const char *path, const char *refobj_path, int *fdp) { char *p; struct try_library_args arg; if (path == NULL) return (NULL); arg.name = name; arg.namelen = strlen(name); arg.buffer = xmalloc(PATH_MAX); arg.buflen = PATH_MAX; arg.fd = -1; p = path_enumerate(path, try_library_path, refobj_path, &arg); *fdp = arg.fd; free(arg.buffer); return (p); } /* * Finds the library with the given name using the directory descriptors * listed in the LD_LIBRARY_PATH_FDS environment variable. * * Returns a freshly-opened close-on-exec file descriptor for the library, * or -1 if the library cannot be found. */ static char * search_library_pathfds(const char *name, const char *path, int *fdp) { char *envcopy, *fdstr, *found, *last_token; size_t len; int dirfd, fd; dbg("%s('%s', '%s', fdp)", __func__, name, path); /* Don't load from user-specified libdirs into setuid binaries. */ if (!trust) return (NULL); /* We can't do anything if LD_LIBRARY_PATH_FDS isn't set. */ if (path == NULL) return (NULL); /* LD_LIBRARY_PATH_FDS only works with relative paths. */ if (name[0] == '/') { dbg("Absolute path (%s) passed to %s", name, __func__); return (NULL); } /* * Use strtok_r() to walk the FD:FD:FD list. This requires a local * copy of the path, as strtok_r rewrites separator tokens * with '\0'. */ found = NULL; envcopy = xstrdup(path); for (fdstr = strtok_r(envcopy, ":", &last_token); fdstr != NULL; fdstr = strtok_r(NULL, ":", &last_token)) { dirfd = parse_integer(fdstr); if (dirfd < 0) { _rtld_error("failed to parse directory FD: '%s'", fdstr); break; } fd = __sys_openat(dirfd, name, O_RDONLY | O_CLOEXEC | O_VERIFY); if (fd >= 0) { *fdp = fd; len = strlen(fdstr) + strlen(name) + 3; found = xmalloc(len); if (rtld_snprintf(found, len, "#%d/%s", dirfd, name) < 0) { _rtld_error("error generating '%d/%s'", dirfd, name); rtld_die(); } dbg("open('%s') => %d", found, fd); break; } } free(envcopy); return (found); } int dlclose(void *handle) { RtldLockState lockstate; int error; wlock_acquire(rtld_bind_lock, &lockstate); error = dlclose_locked(handle, &lockstate); lock_release(rtld_bind_lock, &lockstate); return (error); } static int dlclose_locked(void *handle, RtldLockState *lockstate) { Obj_Entry *root; root = dlcheck(handle); if (root == NULL) return (-1); LD_UTRACE(UTRACE_DLCLOSE_START, handle, NULL, 0, root->dl_refcount, root->path); /* Unreference the object and its dependencies. */ root->dl_refcount--; if (root->refcount == 1) { /* * The object will be no longer referenced, so we must unload * it. First, call the fini functions. */ objlist_call_fini(&list_fini, root, lockstate); unref_dag(root); /* Finish cleaning up the newly-unreferenced objects. */ GDB_STATE(RT_DELETE, &root->linkmap); unload_object(root, lockstate); GDB_STATE(RT_CONSISTENT, NULL); } else unref_dag(root); LD_UTRACE(UTRACE_DLCLOSE_STOP, handle, NULL, 0, 0, NULL); return (0); } char * dlerror(void) { if (*(lockinfo.dlerror_seen()) != 0) return (NULL); *lockinfo.dlerror_seen() = 1; return (lockinfo.dlerror_loc()); } /* * This function is deprecated and has no effect. */ void dllockinit(void *context, void *(*_lock_create)(void *context)__unused, void (*_rlock_acquire)(void *lock) __unused, void (*_wlock_acquire)(void *lock) __unused, void (*_lock_release)(void *lock) __unused, void (*_lock_destroy)(void *lock) __unused, void (*context_destroy)(void *context)) { static void *cur_context; static void (*cur_context_destroy)(void *); /* Just destroy the context from the previous call, if necessary. */ if (cur_context_destroy != NULL) cur_context_destroy(cur_context); cur_context = context; cur_context_destroy = context_destroy; } void * dlopen(const char *name, int mode) { return (rtld_dlopen(name, -1, mode)); } void * fdlopen(int fd, int mode) { return (rtld_dlopen(NULL, fd, mode)); } static void * rtld_dlopen(const char *name, int fd, int mode) { RtldLockState lockstate; int lo_flags; LD_UTRACE(UTRACE_DLOPEN_START, NULL, NULL, 0, mode, name); ld_tracing = (mode & RTLD_TRACE) == 0 ? NULL : "1"; if (ld_tracing != NULL) { rlock_acquire(rtld_bind_lock, &lockstate); if (sigsetjmp(lockstate.env, 0) != 0) lock_upgrade(rtld_bind_lock, &lockstate); environ = __DECONST(char **, *get_program_var_addr("environ", &lockstate)); lock_release(rtld_bind_lock, &lockstate); } lo_flags = RTLD_LO_DLOPEN; if (mode & RTLD_NODELETE) lo_flags |= RTLD_LO_NODELETE; if (mode & RTLD_NOLOAD) lo_flags |= RTLD_LO_NOLOAD; if (mode & RTLD_DEEPBIND) lo_flags |= RTLD_LO_DEEPBIND; if (ld_tracing != NULL) lo_flags |= RTLD_LO_TRACE | RTLD_LO_IGNSTLS; return (dlopen_object(name, fd, obj_main, lo_flags, mode & (RTLD_MODEMASK | RTLD_GLOBAL), NULL)); } static void dlopen_cleanup(Obj_Entry *obj, RtldLockState *lockstate) { obj->dl_refcount--; unref_dag(obj); if (obj->refcount == 0) unload_object(obj, lockstate); } static Obj_Entry * dlopen_object(const char *name, int fd, Obj_Entry *refobj, int lo_flags, int mode, RtldLockState *lockstate) { Obj_Entry *obj; Objlist initlist; RtldLockState mlockstate; int result; dbg( "dlopen_object name \"%s\" fd %d refobj \"%s\" lo_flags %#x mode %#x", name != NULL ? name : "", fd, refobj == NULL ? "" : refobj->path, lo_flags, mode); objlist_init(&initlist); if (lockstate == NULL && !(lo_flags & RTLD_LO_EARLY)) { wlock_acquire(rtld_bind_lock, &mlockstate); lockstate = &mlockstate; } GDB_STATE(RT_ADD, NULL); obj = NULL; if (name == NULL && fd == -1) { obj = obj_main; obj->refcount++; } else { obj = load_object(name, fd, refobj, lo_flags); } if (obj != NULL) { obj->dl_refcount++; if ((mode & RTLD_GLOBAL) != 0 && objlist_find(&list_global, obj) == NULL) objlist_push_tail(&list_global, obj); if (!obj->init_done) { /* We loaded something new and have to init something. */ if ((lo_flags & RTLD_LO_DEEPBIND) != 0) obj->deepbind = true; result = 0; if ((lo_flags & (RTLD_LO_EARLY | RTLD_LO_IGNSTLS)) == 0 && obj->static_tls && !allocate_tls_offset(obj)) { _rtld_error( "%s: No space available for static Thread Local Storage", obj->path); result = -1; } if (result != -1) result = load_needed_objects(obj, lo_flags & (RTLD_LO_DLOPEN | RTLD_LO_EARLY | RTLD_LO_IGNSTLS | RTLD_LO_TRACE)); init_dag(obj); ref_dag(obj); if (result != -1) result = rtld_verify_versions(&obj->dagmembers); if (result != -1 && ld_tracing) goto trace; if (result == -1 || relocate_object_dag(obj, (mode & RTLD_MODEMASK) == RTLD_NOW, &obj_rtld, (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, lockstate) == -1) { dlopen_cleanup(obj, lockstate); obj = NULL; } else if ((lo_flags & RTLD_LO_EARLY) != 0) { /* * Do not call the init functions for early * loaded filtees. The image is still not * initialized enough for them to work. * * Our object is found by the global object list * and will be ordered among all init calls done * right before transferring control to main. */ } else { /* Make list of init functions to call. */ initlist_for_loaded_obj(obj, obj, &initlist); } /* * Process all no_delete or global objects here, given * them own DAGs to prevent their dependencies from * being unloaded. This has to be done after we have * loaded all of the dependencies, so that we do not * miss any. */ if (obj != NULL) process_z(obj); } else { /* * Bump the reference counts for objects on this DAG. If * this is the first dlopen() call for the object that * was already loaded as a dependency, initialize the * dag starting at it. */ init_dag(obj); ref_dag(obj); if ((lo_flags & RTLD_LO_TRACE) != 0) goto trace; } if (obj != NULL && ((lo_flags & RTLD_LO_NODELETE) != 0 || obj->z_nodelete) && !obj->ref_nodel) { dbg("obj %s nodelete", obj->path); ref_dag(obj); obj->z_nodelete = obj->ref_nodel = true; } } LD_UTRACE(UTRACE_DLOPEN_STOP, obj, NULL, 0, obj ? obj->dl_refcount : 0, name); GDB_STATE(RT_CONSISTENT, obj ? &obj->linkmap : NULL); if ((lo_flags & RTLD_LO_EARLY) == 0) { map_stacks_exec(lockstate); if (obj != NULL) distribute_static_tls(&initlist); } if (initlist_objects_ifunc(&initlist, (mode & RTLD_MODEMASK) == RTLD_NOW, (lo_flags & RTLD_LO_EARLY) ? SYMLOOK_EARLY : 0, lockstate) == -1) { objlist_clear(&initlist); dlopen_cleanup(obj, lockstate); if (lockstate == &mlockstate) lock_release(rtld_bind_lock, lockstate); return (NULL); } if ((lo_flags & RTLD_LO_EARLY) == 0) { /* Call the init functions. */ objlist_call_init(&initlist, lockstate); } objlist_clear(&initlist); if (lockstate == &mlockstate) lock_release(rtld_bind_lock, lockstate); return (obj); trace: trace_loaded_objects(obj, false); if (lockstate == &mlockstate) lock_release(rtld_bind_lock, lockstate); exit(0); } static void * do_dlsym(void *handle, const char *name, void *retaddr, const Ver_Entry *ve, int flags) { DoneList donelist; const Obj_Entry *obj, *defobj; const Elf_Sym *def; SymLook req; RtldLockState lockstate; tls_index ti; void *sym; int res; def = NULL; defobj = NULL; symlook_init(&req, name); req.ventry = ve; req.flags = flags | SYMLOOK_IN_PLT; req.lockstate = &lockstate; LD_UTRACE(UTRACE_DLSYM_START, handle, NULL, 0, 0, name); rlock_acquire(rtld_bind_lock, &lockstate); if (sigsetjmp(lockstate.env, 0) != 0) lock_upgrade(rtld_bind_lock, &lockstate); if (handle == NULL || handle == RTLD_NEXT || handle == RTLD_DEFAULT || handle == RTLD_SELF) { if ((obj = obj_from_addr(retaddr)) == NULL) { _rtld_error("Cannot determine caller's shared object"); lock_release(rtld_bind_lock, &lockstate); LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); return (NULL); } if (handle == NULL) { /* Just the caller's shared object. */ res = symlook_obj(&req, obj); if (res == 0) { def = req.sym_out; defobj = req.defobj_out; } } else if (handle == RTLD_NEXT || /* Objects after caller's */ handle == RTLD_SELF) { /* ... caller included */ if (handle == RTLD_NEXT) obj = globallist_next(obj); for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { if (obj->marker) continue; res = symlook_obj(&req, obj); if (res == 0) { if (def == NULL || (ld_dynamic_weak && ELF_ST_BIND( req.sym_out->st_info) != STB_WEAK)) { def = req.sym_out; defobj = req.defobj_out; if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) break; } } } /* * Search the dynamic linker itself, and possibly * resolve the symbol from there. This is how the * application links to dynamic linker services such as * dlopen. Note that we ignore ld_dynamic_weak == false * case, always overriding weak symbols by rtld * definitions. */ if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { res = symlook_obj(&req, &obj_rtld); if (res == 0) { def = req.sym_out; defobj = req.defobj_out; } } } else { assert(handle == RTLD_DEFAULT); res = symlook_default(&req, obj); if (res == 0) { defobj = req.defobj_out; def = req.sym_out; } } } else { if ((obj = dlcheck(handle)) == NULL) { lock_release(rtld_bind_lock, &lockstate); LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); return (NULL); } donelist_init(&donelist); if (obj->mainprog) { /* Handle obtained by dlopen(NULL, ...) implies global * scope. */ res = symlook_global(&req, &donelist); if (res == 0) { def = req.sym_out; defobj = req.defobj_out; } /* * Search the dynamic linker itself, and possibly * resolve the symbol from there. This is how the * application links to dynamic linker services such as * dlopen. */ if (def == NULL || ELF_ST_BIND(def->st_info) == STB_WEAK) { res = symlook_obj(&req, &obj_rtld); if (res == 0) { def = req.sym_out; defobj = req.defobj_out; } } } else { /* Search the whole DAG rooted at the given object. */ res = symlook_list(&req, &obj->dagmembers, &donelist); if (res == 0) { def = req.sym_out; defobj = req.defobj_out; } } } if (def != NULL) { lock_release(rtld_bind_lock, &lockstate); /* * The value required by the caller is derived from the value * of the symbol. this is simply the relocated value of the * symbol. */ if (ELF_ST_TYPE(def->st_info) == STT_FUNC) sym = make_function_pointer(def, defobj); else if (ELF_ST_TYPE(def->st_info) == STT_GNU_IFUNC) sym = rtld_resolve_ifunc(defobj, def); else if (ELF_ST_TYPE(def->st_info) == STT_TLS) { ti.ti_module = defobj->tlsindex; ti.ti_offset = def->st_value - TLS_DTV_OFFSET; sym = __tls_get_addr(&ti); } else sym = defobj->relocbase + def->st_value; LD_UTRACE(UTRACE_DLSYM_STOP, handle, sym, 0, 0, name); return (sym); } _rtld_error("Undefined symbol \"%s%s%s\"", name, ve != NULL ? "@" : "", ve != NULL ? ve->name : ""); lock_release(rtld_bind_lock, &lockstate); LD_UTRACE(UTRACE_DLSYM_STOP, handle, NULL, 0, 0, name); return (NULL); } void * dlsym(void *handle, const char *name) { return (do_dlsym(handle, name, __builtin_return_address(0), NULL, SYMLOOK_DLSYM)); } dlfunc_t dlfunc(void *handle, const char *name) { union { void *d; dlfunc_t f; } rv; rv.d = do_dlsym(handle, name, __builtin_return_address(0), NULL, SYMLOOK_DLSYM); return (rv.f); } void * dlvsym(void *handle, const char *name, const char *version) { Ver_Entry ventry; ventry.name = version; ventry.file = NULL; ventry.hash = elf_hash(version); ventry.flags = 0; return (do_dlsym(handle, name, __builtin_return_address(0), &ventry, SYMLOOK_DLSYM)); } int _rtld_addr_phdr(const void *addr, struct dl_phdr_info *phdr_info) { const Obj_Entry *obj; RtldLockState lockstate; rlock_acquire(rtld_bind_lock, &lockstate); obj = obj_from_addr(addr); if (obj == NULL) { _rtld_error("No shared object contains address"); lock_release(rtld_bind_lock, &lockstate); return (0); } rtld_fill_dl_phdr_info(obj, phdr_info); lock_release(rtld_bind_lock, &lockstate); return (1); } int dladdr(const void *addr, Dl_info *info) { const Obj_Entry *obj; const Elf_Sym *def; void *symbol_addr; unsigned long symoffset; RtldLockState lockstate; rlock_acquire(rtld_bind_lock, &lockstate); obj = obj_from_addr(addr); if (obj == NULL) { _rtld_error("No shared object contains address"); lock_release(rtld_bind_lock, &lockstate); return (0); } info->dli_fname = obj->path; info->dli_fbase = obj->mapbase; info->dli_saddr = (void *)0; info->dli_sname = NULL; /* * Walk the symbol list looking for the symbol whose address is * closest to the address sent in. */ for (symoffset = 0; symoffset < obj->dynsymcount; symoffset++) { def = obj->symtab + symoffset; /* * For skip the symbol if st_shndx is either SHN_UNDEF or * SHN_COMMON. */ if (def->st_shndx == SHN_UNDEF || def->st_shndx == SHN_COMMON) continue; /* * If the symbol is greater than the specified address, or if it * is further away from addr than the current nearest symbol, * then reject it. */ symbol_addr = obj->relocbase + def->st_value; if (symbol_addr > addr || symbol_addr < info->dli_saddr) continue; /* Update our idea of the nearest symbol. */ info->dli_sname = obj->strtab + def->st_name; info->dli_saddr = symbol_addr; /* Exact match? */ if (info->dli_saddr == addr) break; } lock_release(rtld_bind_lock, &lockstate); return (1); } int dlinfo(void *handle, int request, void *p) { const Obj_Entry *obj; RtldLockState lockstate; int error; rlock_acquire(rtld_bind_lock, &lockstate); if (handle == NULL || handle == RTLD_SELF) { void *retaddr; retaddr = __builtin_return_address(0); /* __GNUC__ only */ if ((obj = obj_from_addr(retaddr)) == NULL) _rtld_error("Cannot determine caller's shared object"); } else obj = dlcheck(handle); if (obj == NULL) { lock_release(rtld_bind_lock, &lockstate); return (-1); } error = 0; switch (request) { case RTLD_DI_LINKMAP: *((struct link_map const **)p) = &obj->linkmap; break; case RTLD_DI_ORIGIN: error = rtld_dirname(obj->path, p); break; case RTLD_DI_SERINFOSIZE: case RTLD_DI_SERINFO: error = do_search_info(obj, request, (struct dl_serinfo *)p); break; default: _rtld_error("Invalid request %d passed to dlinfo()", request); error = -1; } lock_release(rtld_bind_lock, &lockstate); return (error); } static void rtld_fill_dl_phdr_info(const Obj_Entry *obj, struct dl_phdr_info *phdr_info) { phdr_info->dlpi_addr = (Elf_Addr)obj->relocbase; phdr_info->dlpi_name = obj->path; phdr_info->dlpi_phdr = obj->phdr; phdr_info->dlpi_phnum = obj->phnum; phdr_info->dlpi_tls_modid = obj->tlsindex; phdr_info->dlpi_tls_data = (char *)tls_get_addr_slow(_tcb_get(), obj->tlsindex, 0, true); phdr_info->dlpi_adds = obj_loads; phdr_info->dlpi_subs = obj_loads - obj_count; } /* * It's completely UB to actually use this, so extreme caution is advised. It's * probably not what you want. */ int _dl_iterate_phdr_locked(__dl_iterate_hdr_callback callback, void *param) { struct dl_phdr_info phdr_info; Obj_Entry *obj; int error; for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL; obj = globallist_next(obj)) { rtld_fill_dl_phdr_info(obj, &phdr_info); error = callback(&phdr_info, sizeof(phdr_info), param); if (error != 0) return (error); } rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); return (callback(&phdr_info, sizeof(phdr_info), param)); } int dl_iterate_phdr(__dl_iterate_hdr_callback callback, void *param) { struct dl_phdr_info phdr_info; Obj_Entry *obj, marker; RtldLockState bind_lockstate, phdr_lockstate; int error; init_marker(&marker); error = 0; wlock_acquire(rtld_phdr_lock, &phdr_lockstate); wlock_acquire(rtld_bind_lock, &bind_lockstate); for (obj = globallist_curr(TAILQ_FIRST(&obj_list)); obj != NULL;) { TAILQ_INSERT_AFTER(&obj_list, obj, &marker, next); rtld_fill_dl_phdr_info(obj, &phdr_info); hold_object(obj); lock_release(rtld_bind_lock, &bind_lockstate); error = callback(&phdr_info, sizeof phdr_info, param); wlock_acquire(rtld_bind_lock, &bind_lockstate); unhold_object(obj); obj = globallist_next(&marker); TAILQ_REMOVE(&obj_list, &marker, next); if (error != 0) { lock_release(rtld_bind_lock, &bind_lockstate); lock_release(rtld_phdr_lock, &phdr_lockstate); return (error); } } if (error == 0) { rtld_fill_dl_phdr_info(&obj_rtld, &phdr_info); lock_release(rtld_bind_lock, &bind_lockstate); error = callback(&phdr_info, sizeof(phdr_info), param); } lock_release(rtld_phdr_lock, &phdr_lockstate); return (error); } static void * fill_search_info(const char *dir, size_t dirlen, void *param) { struct fill_search_info_args *arg; arg = param; if (arg->request == RTLD_DI_SERINFOSIZE) { arg->serinfo->dls_cnt++; arg->serinfo->dls_size += sizeof(struct dl_serpath) + dirlen + 1; } else { struct dl_serpath *s_entry; s_entry = arg->serpath; s_entry->dls_name = arg->strspace; s_entry->dls_flags = arg->flags; strncpy(arg->strspace, dir, dirlen); arg->strspace[dirlen] = '\0'; arg->strspace += dirlen + 1; arg->serpath++; } return (NULL); } static int do_search_info(const Obj_Entry *obj, int request, struct dl_serinfo *info) { struct dl_serinfo _info; struct fill_search_info_args args; args.request = RTLD_DI_SERINFOSIZE; args.serinfo = &_info; _info.dls_size = __offsetof(struct dl_serinfo, dls_serpath); _info.dls_cnt = 0; path_enumerate(obj->rpath, fill_search_info, NULL, &args); path_enumerate(ld_library_path, fill_search_info, NULL, &args); path_enumerate(obj->runpath, fill_search_info, NULL, &args); path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args); if (!obj->z_nodeflib) path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args); if (request == RTLD_DI_SERINFOSIZE) { info->dls_size = _info.dls_size; info->dls_cnt = _info.dls_cnt; return (0); } if (info->dls_cnt != _info.dls_cnt || info->dls_size != _info.dls_size) { _rtld_error( "Uninitialized Dl_serinfo struct passed to dlinfo()"); return (-1); } args.request = RTLD_DI_SERINFO; args.serinfo = info; args.serpath = &info->dls_serpath[0]; args.strspace = (char *)&info->dls_serpath[_info.dls_cnt]; args.flags = LA_SER_RUNPATH; if (path_enumerate(obj->rpath, fill_search_info, NULL, &args) != NULL) return (-1); args.flags = LA_SER_LIBPATH; if (path_enumerate(ld_library_path, fill_search_info, NULL, &args) != NULL) return (-1); args.flags = LA_SER_RUNPATH; if (path_enumerate(obj->runpath, fill_search_info, NULL, &args) != NULL) return (-1); args.flags = LA_SER_CONFIG; if (path_enumerate(gethints(obj->z_nodeflib), fill_search_info, NULL, &args) != NULL) return (-1); args.flags = LA_SER_DEFAULT; if (!obj->z_nodeflib && path_enumerate(ld_standard_library_path, fill_search_info, NULL, &args) != NULL) return (-1); return (0); } static int rtld_dirname(const char *path, char *bname) { const char *endp; /* Empty or NULL string gets treated as "." */ if (path == NULL || *path == '\0') { bname[0] = '.'; bname[1] = '\0'; return (0); } /* Strip trailing slashes */ endp = path + strlen(path) - 1; while (endp > path && *endp == '/') endp--; /* Find the start of the dir */ while (endp > path && *endp != '/') endp--; /* Either the dir is "/" or there are no slashes */ if (endp == path) { bname[0] = *endp == '/' ? '/' : '.'; bname[1] = '\0'; return (0); } else { do { endp--; } while (endp > path && *endp == '/'); } if (endp - path + 2 > PATH_MAX) { _rtld_error("Filename is too long: %s", path); return (-1); } strncpy(bname, path, endp - path + 1); bname[endp - path + 1] = '\0'; return (0); } static int rtld_dirname_abs(const char *path, char *base) { char *last; if (realpath(path, base) == NULL) { _rtld_error("realpath \"%s\" failed (%s)", path, rtld_strerror(errno)); return (-1); } dbg("%s -> %s", path, base); last = strrchr(base, '/'); if (last == NULL) { _rtld_error("non-abs result from realpath \"%s\"", path); return (-1); } if (last != base) *last = '\0'; return (0); } static void linkmap_add(Obj_Entry *obj) { struct link_map *l, *prev; l = &obj->linkmap; l->l_name = obj->path; l->l_base = obj->mapbase; l->l_ld = obj->dynamic; l->l_addr = obj->relocbase; if (r_debug.r_map == NULL) { r_debug.r_map = l; return; } /* * Scan to the end of the list, but not past the entry for the * dynamic linker, which we want to keep at the very end. */ for (prev = r_debug.r_map; prev->l_next != NULL && prev->l_next != &obj_rtld.linkmap; prev = prev->l_next) ; /* Link in the new entry. */ l->l_prev = prev; l->l_next = prev->l_next; if (l->l_next != NULL) l->l_next->l_prev = l; prev->l_next = l; } static void linkmap_delete(Obj_Entry *obj) { struct link_map *l; l = &obj->linkmap; if (l->l_prev == NULL) { if ((r_debug.r_map = l->l_next) != NULL) l->l_next->l_prev = NULL; return; } if ((l->l_prev->l_next = l->l_next) != NULL) l->l_next->l_prev = l->l_prev; } /* * Function for the debugger to set a breakpoint on to gain control. * * The two parameters allow the debugger to easily find and determine * what the runtime loader is doing and to whom it is doing it. * * When the loadhook trap is hit (r_debug_state, set at program * initialization), the arguments can be found on the stack: * * +8 struct link_map *m * +4 struct r_debug *rd * +0 RetAddr */ void r_debug_state(struct r_debug *rd __unused, struct link_map *m __unused) { /* * The following is a hack to force the compiler to emit calls to * this function, even when optimizing. If the function is empty, * the compiler is not obliged to emit any code for calls to it, * even when marked __noinline. However, gdb depends on those * calls being made. */ __compiler_membar(); } /* * A function called after init routines have completed. This can be used to * break before a program's entry routine is called, and can be used when * main is not available in the symbol table. */ void _r_debug_postinit(struct link_map *m __unused) { /* See r_debug_state(). */ __compiler_membar(); } static void release_object(Obj_Entry *obj) { if (obj->holdcount > 0) { obj->unholdfree = true; return; } munmap(obj->mapbase, obj->mapsize); linkmap_delete(obj); obj_free(obj); } /* * Get address of the pointer variable in the main program. * Prefer non-weak symbol over the weak one. */ static const void ** get_program_var_addr(const char *name, RtldLockState *lockstate) { SymLook req; DoneList donelist; symlook_init(&req, name); req.lockstate = lockstate; donelist_init(&donelist); if (symlook_global(&req, &donelist) != 0) return (NULL); if (ELF_ST_TYPE(req.sym_out->st_info) == STT_FUNC) return ((const void **)make_function_pointer(req.sym_out, req.defobj_out)); else if (ELF_ST_TYPE(req.sym_out->st_info) == STT_GNU_IFUNC) return ((const void **)rtld_resolve_ifunc(req.defobj_out, req.sym_out)); else return ((const void **)(req.defobj_out->relocbase + req.sym_out->st_value)); } /* * Set a pointer variable in the main program to the given value. This * is used to set key variables such as "environ" before any of the * init functions are called. */ static void set_program_var(const char *name, const void *value) { const void **addr; if ((addr = get_program_var_addr(name, NULL)) != NULL) { dbg("\"%s\": *%p <-- %p", name, addr, value); *addr = value; } } /* * Search the global objects, including dependencies and main object, * for the given symbol. */ static int symlook_global(SymLook *req, DoneList *donelist) { SymLook req1; const Objlist_Entry *elm; int res; symlook_init_from_req(&req1, req); /* Search all objects loaded at program start up. */ if (req->defobj_out == NULL || (ld_dynamic_weak && ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK)) { res = symlook_list(&req1, &list_main, donelist); if (res == 0 && (!ld_dynamic_weak || req->defobj_out == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { req->sym_out = req1.sym_out; req->defobj_out = req1.defobj_out; assert(req->defobj_out != NULL); } } /* Search all DAGs whose roots are RTLD_GLOBAL objects. */ STAILQ_FOREACH(elm, &list_global, link) { if (req->defobj_out != NULL && (!ld_dynamic_weak || ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) break; res = symlook_list(&req1, &elm->obj->dagmembers, donelist); if (res == 0 && (req->defobj_out == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { req->sym_out = req1.sym_out; req->defobj_out = req1.defobj_out; assert(req->defobj_out != NULL); } } return (req->sym_out != NULL ? 0 : ESRCH); } /* * Given a symbol name in a referencing object, find the corresponding * definition of the symbol. Returns a pointer to the symbol, or NULL if * no definition was found. Returns a pointer to the Obj_Entry of the * defining object via the reference parameter DEFOBJ_OUT. */ static int symlook_default(SymLook *req, const Obj_Entry *refobj) { DoneList donelist; const Objlist_Entry *elm; SymLook req1; int res; donelist_init(&donelist); symlook_init_from_req(&req1, req); /* * Look first in the referencing object if linked symbolically, * and similarly handle protected symbols. */ res = symlook_obj(&req1, refobj); if (res == 0 && (refobj->symbolic || ELF_ST_VISIBILITY(req1.sym_out->st_other) == STV_PROTECTED || refobj->deepbind)) { req->sym_out = req1.sym_out; req->defobj_out = req1.defobj_out; assert(req->defobj_out != NULL); } if (refobj->symbolic || req->defobj_out != NULL || refobj->deepbind) donelist_check(&donelist, refobj); if (!refobj->deepbind) symlook_global(req, &donelist); /* Search all dlopened DAGs containing the referencing object. */ STAILQ_FOREACH(elm, &refobj->dldags, link) { if (req->sym_out != NULL && (!ld_dynamic_weak || ELF_ST_BIND(req->sym_out->st_info) != STB_WEAK)) break; res = symlook_list(&req1, &elm->obj->dagmembers, &donelist); if (res == 0 && (req->sym_out == NULL || ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { req->sym_out = req1.sym_out; req->defobj_out = req1.defobj_out; assert(req->defobj_out != NULL); } } if (refobj->deepbind) symlook_global(req, &donelist); /* * Search the dynamic linker itself, and possibly resolve the * symbol from there. This is how the application links to * dynamic linker services such as dlopen. */ if (req->sym_out == NULL || ELF_ST_BIND(req->sym_out->st_info) == STB_WEAK) { res = symlook_obj(&req1, &obj_rtld); if (res == 0) { req->sym_out = req1.sym_out; req->defobj_out = req1.defobj_out; assert(req->defobj_out != NULL); } } return (req->sym_out != NULL ? 0 : ESRCH); } static int symlook_list(SymLook *req, const Objlist *objlist, DoneList *dlp) { const Elf_Sym *def; const Obj_Entry *defobj; const Objlist_Entry *elm; SymLook req1; int res; def = NULL; defobj = NULL; STAILQ_FOREACH(elm, objlist, link) { if (donelist_check(dlp, elm->obj)) continue; symlook_init_from_req(&req1, req); if ((res = symlook_obj(&req1, elm->obj)) == 0) { if (def == NULL || (ld_dynamic_weak && ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { def = req1.sym_out; defobj = req1.defobj_out; if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) break; } } } if (def != NULL) { req->sym_out = def; req->defobj_out = defobj; return (0); } return (ESRCH); } /* * Search the chain of DAGS cointed to by the given Needed_Entry * for a symbol of the given name. Each DAG is scanned completely * before advancing to the next one. Returns a pointer to the symbol, * or NULL if no definition was found. */ static int symlook_needed(SymLook *req, const Needed_Entry *needed, DoneList *dlp) { const Elf_Sym *def; const Needed_Entry *n; const Obj_Entry *defobj; SymLook req1; int res; def = NULL; defobj = NULL; symlook_init_from_req(&req1, req); for (n = needed; n != NULL; n = n->next) { if (n->obj == NULL || (res = symlook_list(&req1, &n->obj->dagmembers, dlp)) != 0) continue; if (def == NULL || (ld_dynamic_weak && ELF_ST_BIND(req1.sym_out->st_info) != STB_WEAK)) { def = req1.sym_out; defobj = req1.defobj_out; if (!ld_dynamic_weak || ELF_ST_BIND(def->st_info) != STB_WEAK) break; } } if (def != NULL) { req->sym_out = def; req->defobj_out = defobj; return (0); } return (ESRCH); } static int symlook_obj_load_filtees(SymLook *req, SymLook *req1, const Obj_Entry *obj, Needed_Entry *needed) { DoneList donelist; int flags; flags = (req->flags & SYMLOOK_EARLY) != 0 ? RTLD_LO_EARLY : 0; load_filtees(__DECONST(Obj_Entry *, obj), flags, req->lockstate); donelist_init(&donelist); symlook_init_from_req(req1, req); return (symlook_needed(req1, needed, &donelist)); } /* * Search the symbol table of a single shared object for a symbol of * the given name and version, if requested. Returns a pointer to the * symbol, or NULL if no definition was found. If the object is * filter, return filtered symbol from filtee. * * The symbol's hash value is passed in for efficiency reasons; that * eliminates many recomputations of the hash value. */ int symlook_obj(SymLook *req, const Obj_Entry *obj) { SymLook req1; int res, mres; /* * If there is at least one valid hash at this point, we prefer to * use the faster GNU version if available. */ if (obj->valid_hash_gnu) mres = symlook_obj1_gnu(req, obj); else if (obj->valid_hash_sysv) mres = symlook_obj1_sysv(req, obj); else return (EINVAL); if (mres == 0) { if (obj->needed_filtees != NULL) { res = symlook_obj_load_filtees(req, &req1, obj, obj->needed_filtees); if (res == 0) { req->sym_out = req1.sym_out; req->defobj_out = req1.defobj_out; } return (res); } if (obj->needed_aux_filtees != NULL) { res = symlook_obj_load_filtees(req, &req1, obj, obj->needed_aux_filtees); if (res == 0) { req->sym_out = req1.sym_out; req->defobj_out = req1.defobj_out; return (res); } } } return (mres); } /* Symbol match routine common to both hash functions */ static bool matched_symbol(SymLook *req, const Obj_Entry *obj, Sym_Match_Result *result, const unsigned long symnum) { Elf_Versym verndx; const Elf_Sym *symp; const char *strp; symp = obj->symtab + symnum; strp = obj->strtab + symp->st_name; switch (ELF_ST_TYPE(symp->st_info)) { case STT_FUNC: case STT_NOTYPE: case STT_OBJECT: case STT_COMMON: case STT_GNU_IFUNC: if (symp->st_value == 0) return (false); /* fallthrough */ case STT_TLS: if (symp->st_shndx != SHN_UNDEF) break; else if (((req->flags & SYMLOOK_IN_PLT) == 0) && (ELF_ST_TYPE(symp->st_info) == STT_FUNC)) break; /* fallthrough */ default: return (false); } if (req->name[0] != strp[0] || strcmp(req->name, strp) != 0) return (false); if (req->ventry == NULL) { if (obj->versyms != NULL) { verndx = VER_NDX(obj->versyms[symnum]); if (verndx > obj->vernum) { _rtld_error( "%s: symbol %s references wrong version %d", obj->path, obj->strtab + symnum, verndx); return (false); } /* * If we are not called from dlsym (i.e. this * is a normal relocation from unversioned * binary), accept the symbol immediately if * it happens to have first version after this * shared object became versioned. Otherwise, * if symbol is versioned and not hidden, * remember it. If it is the only symbol with * this name exported by the shared object, it * will be returned as a match by the calling * function. If symbol is global (verndx < 2) * accept it unconditionally. */ if ((req->flags & SYMLOOK_DLSYM) == 0 && verndx == VER_NDX_GIVEN) { result->sym_out = symp; return (true); } else if (verndx >= VER_NDX_GIVEN) { if ((obj->versyms[symnum] & VER_NDX_HIDDEN) == 0) { if (result->vsymp == NULL) result->vsymp = symp; result->vcount++; } return (false); } } result->sym_out = symp; return (true); } if (obj->versyms == NULL) { if (object_match_name(obj, req->ventry->name)) { _rtld_error( "%s: object %s should provide version %s for symbol %s", obj_rtld.path, obj->path, req->ventry->name, obj->strtab + symnum); return (false); } } else { verndx = VER_NDX(obj->versyms[symnum]); if (verndx > obj->vernum) { _rtld_error("%s: symbol %s references wrong version %d", obj->path, obj->strtab + symnum, verndx); return (false); } if (obj->vertab[verndx].hash != req->ventry->hash || strcmp(obj->vertab[verndx].name, req->ventry->name)) { /* * Version does not match. Look if this is a * global symbol and if it is not hidden. If * global symbol (verndx < 2) is available, * use it. Do not return symbol if we are * called by dlvsym, because dlvsym looks for * a specific version and default one is not * what dlvsym wants. */ if ((req->flags & SYMLOOK_DLSYM) || (verndx >= VER_NDX_GIVEN) || (obj->versyms[symnum] & VER_NDX_HIDDEN)) return (false); } } result->sym_out = symp; return (true); } /* * Search for symbol using SysV hash function. * obj->buckets is known not to be NULL at this point; the test for this was * performed with the obj->valid_hash_sysv assignment. */ static int symlook_obj1_sysv(SymLook *req, const Obj_Entry *obj) { unsigned long symnum; Sym_Match_Result matchres; matchres.sym_out = NULL; matchres.vsymp = NULL; matchres.vcount = 0; for (symnum = obj->buckets[req->hash % obj->nbuckets]; symnum != STN_UNDEF; symnum = obj->chains[symnum]) { if (symnum >= obj->nchains) return (ESRCH); /* Bad object */ if (matched_symbol(req, obj, &matchres, symnum)) { req->sym_out = matchres.sym_out; req->defobj_out = obj; return (0); } } if (matchres.vcount == 1) { req->sym_out = matchres.vsymp; req->defobj_out = obj; return (0); } return (ESRCH); } /* Search for symbol using GNU hash function */ static int symlook_obj1_gnu(SymLook *req, const Obj_Entry *obj) { Elf_Addr bloom_word; const Elf32_Word *hashval; Elf32_Word bucket; Sym_Match_Result matchres; unsigned int h1, h2; unsigned long symnum; matchres.sym_out = NULL; matchres.vsymp = NULL; matchres.vcount = 0; /* Pick right bitmask word from Bloom filter array */ bloom_word = obj->bloom_gnu[(req->hash_gnu / __ELF_WORD_SIZE) & obj->maskwords_bm_gnu]; /* Calculate modulus word size of gnu hash and its derivative */ h1 = req->hash_gnu & (__ELF_WORD_SIZE - 1); h2 = ((req->hash_gnu >> obj->shift2_gnu) & (__ELF_WORD_SIZE - 1)); /* Filter out the "definitely not in set" queries */ if (((bloom_word >> h1) & (bloom_word >> h2) & 1) == 0) return (ESRCH); /* Locate hash chain and corresponding value element*/ bucket = obj->buckets_gnu[req->hash_gnu % obj->nbuckets_gnu]; if (bucket == 0) return (ESRCH); hashval = &obj->chain_zero_gnu[bucket]; do { if (((*hashval ^ req->hash_gnu) >> 1) == 0) { symnum = hashval - obj->chain_zero_gnu; if (matched_symbol(req, obj, &matchres, symnum)) { req->sym_out = matchres.sym_out; req->defobj_out = obj; return (0); } } } while ((*hashval++ & 1) == 0); if (matchres.vcount == 1) { req->sym_out = matchres.vsymp; req->defobj_out = obj; return (0); } return (ESRCH); } static void trace_calc_fmts(const char **main_local, const char **fmt1, const char **fmt2) { *main_local = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_PROGNAME); if (*main_local == NULL) *main_local = ""; *fmt1 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT1); if (*fmt1 == NULL) *fmt1 = "\t%o => %p (%x)\n"; *fmt2 = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2); if (*fmt2 == NULL) *fmt2 = "\t%o (%x)\n"; } static void trace_print_obj(Obj_Entry *obj, const char *name, const char *path, const char *main_local, const char *fmt1, const char *fmt2) { const char *fmt; int c; if (fmt1 == NULL) fmt = fmt2; else /* XXX bogus */ fmt = strncmp(name, "lib", 3) == 0 ? fmt1 : fmt2; while ((c = *fmt++) != '\0') { switch (c) { default: rtld_putchar(c); continue; case '\\': switch (c = *fmt) { case '\0': continue; case 'n': rtld_putchar('\n'); break; case 't': rtld_putchar('\t'); break; } break; case '%': switch (c = *fmt) { case '\0': continue; case '%': default: rtld_putchar(c); break; case 'A': rtld_putstr(main_local); break; case 'a': rtld_putstr(obj_main->path); break; case 'o': rtld_putstr(name); break; case 'p': rtld_putstr(path); break; case 'x': rtld_printf("%p", obj != NULL ? obj->mapbase : NULL); break; } break; } ++fmt; } } static void trace_loaded_objects(Obj_Entry *obj, bool show_preload) { const char *fmt1, *fmt2, *main_local; const char *name, *path; bool first_spurious, list_containers; trace_calc_fmts(&main_local, &fmt1, &fmt2); list_containers = ld_get_env_var(LD_TRACE_LOADED_OBJECTS_ALL) != NULL; for (; obj != NULL; obj = TAILQ_NEXT(obj, next)) { Needed_Entry *needed; if (obj->marker) continue; if (list_containers && obj->needed != NULL) rtld_printf("%s:\n", obj->path); for (needed = obj->needed; needed; needed = needed->next) { if (needed->obj != NULL) { if (needed->obj->traced && !list_containers) continue; needed->obj->traced = true; path = needed->obj->path; } else path = "not found"; name = obj->strtab + needed->name; trace_print_obj(needed->obj, name, path, main_local, fmt1, fmt2); } } if (show_preload) { if (ld_get_env_var(LD_TRACE_LOADED_OBJECTS_FMT2) == NULL) fmt2 = "\t%p (%x)\n"; first_spurious = true; TAILQ_FOREACH(obj, &obj_list, next) { if (obj->marker || obj == obj_main || obj->traced) continue; if (list_containers && first_spurious) { rtld_printf("[preloaded]\n"); first_spurious = false; } Name_Entry *fname = STAILQ_FIRST(&obj->names); name = fname == NULL ? "" : fname->name; trace_print_obj(obj, name, obj->path, main_local, NULL, fmt2); } } } /* * Unload a dlopened object and its dependencies from memory and from * our data structures. It is assumed that the DAG rooted in the * object has already been unreferenced, and that the object has a * reference count of 0. */ static void unload_object(Obj_Entry *root, RtldLockState *lockstate) { Obj_Entry marker, *obj, *next; assert(root->refcount == 0); /* * Pass over the DAG removing unreferenced objects from * appropriate lists. */ unlink_object(root); /* Unmap all objects that are no longer referenced. */ for (obj = TAILQ_FIRST(&obj_list); obj != NULL; obj = next) { next = TAILQ_NEXT(obj, next); if (obj->marker || obj->refcount != 0) continue; LD_UTRACE(UTRACE_UNLOAD_OBJECT, obj, obj->mapbase, obj->mapsize, 0, obj->path); dbg("unloading \"%s\"", obj->path); /* * Unlink the object now to prevent new references from * being acquired while the bind lock is dropped in * recursive dlclose() invocations. */ TAILQ_REMOVE(&obj_list, obj, next); obj_count--; if (obj->filtees_loaded) { if (next != NULL) { init_marker(&marker); TAILQ_INSERT_BEFORE(next, &marker, next); unload_filtees(obj, lockstate); next = TAILQ_NEXT(&marker, next); TAILQ_REMOVE(&obj_list, &marker, next); } else unload_filtees(obj, lockstate); } release_object(obj); } } static void unlink_object(Obj_Entry *root) { Objlist_Entry *elm; if (root->refcount == 0) { /* Remove the object from the RTLD_GLOBAL list. */ objlist_remove(&list_global, root); /* Remove the object from all objects' DAG lists. */ STAILQ_FOREACH(elm, &root->dagmembers, link) { objlist_remove(&elm->obj->dldags, root); if (elm->obj != root) unlink_object(elm->obj); } } } static void ref_dag(Obj_Entry *root) { Objlist_Entry *elm; assert(root->dag_inited); STAILQ_FOREACH(elm, &root->dagmembers, link) elm->obj->refcount++; } static void unref_dag(Obj_Entry *root) { Objlist_Entry *elm; assert(root->dag_inited); STAILQ_FOREACH(elm, &root->dagmembers, link) elm->obj->refcount--; } /* * Common code for MD __tls_get_addr(). */ static void * tls_get_addr_slow(struct tcb *tcb, int index, size_t offset, bool locked) { struct dtv *newdtv, *dtv; RtldLockState lockstate; int to_copy; dtv = tcb->tcb_dtv; /* Check dtv generation in case new modules have arrived */ if (dtv->dtv_gen != tls_dtv_generation) { if (!locked) wlock_acquire(rtld_bind_lock, &lockstate); newdtv = xcalloc(1, sizeof(struct dtv) + tls_max_index * sizeof(struct dtv_slot)); to_copy = dtv->dtv_size; if (to_copy > tls_max_index) to_copy = tls_max_index; memcpy(newdtv->dtv_slots, dtv->dtv_slots, to_copy * sizeof(struct dtv_slot)); newdtv->dtv_gen = tls_dtv_generation; newdtv->dtv_size = tls_max_index; free(dtv); if (!locked) lock_release(rtld_bind_lock, &lockstate); dtv = tcb->tcb_dtv = newdtv; } /* Dynamically allocate module TLS if necessary */ if (dtv->dtv_slots[index - 1].dtvs_tls == 0) { /* Signal safe, wlock will block out signals. */ if (!locked) wlock_acquire(rtld_bind_lock, &lockstate); if (!dtv->dtv_slots[index - 1].dtvs_tls) dtv->dtv_slots[index - 1].dtvs_tls = allocate_module_tls(tcb, index); if (!locked) lock_release(rtld_bind_lock, &lockstate); } return (dtv->dtv_slots[index - 1].dtvs_tls + offset); } void * tls_get_addr_common(struct tcb *tcb, int index, size_t offset) { struct dtv *dtv; dtv = tcb->tcb_dtv; /* Check dtv generation in case new modules have arrived */ if (__predict_true(dtv->dtv_gen == tls_dtv_generation && dtv->dtv_slots[index - 1].dtvs_tls != 0)) return (dtv->dtv_slots[index - 1].dtvs_tls + offset); return (tls_get_addr_slow(tcb, index, offset, false)); } static struct tcb * tcb_from_tcb_list_entry(struct tcb_list_entry *tcbelm) { #ifdef TLS_VARIANT_I return ((struct tcb *)((char *)tcbelm - tcb_list_entry_offset)); #else return ((struct tcb *)((char *)tcbelm + tcb_list_entry_offset)); #endif } static struct tcb_list_entry * tcb_list_entry_from_tcb(struct tcb *tcb) { #ifdef TLS_VARIANT_I return ((struct tcb_list_entry *)((char *)tcb + tcb_list_entry_offset)); #else return ((struct tcb_list_entry *)((char *)tcb - tcb_list_entry_offset)); #endif } static void tcb_list_insert(struct tcb *tcb) { struct tcb_list_entry *tcbelm; tcbelm = tcb_list_entry_from_tcb(tcb); TAILQ_INSERT_TAIL(&tcb_list, tcbelm, next); } static void tcb_list_remove(struct tcb *tcb) { struct tcb_list_entry *tcbelm; tcbelm = tcb_list_entry_from_tcb(tcb); TAILQ_REMOVE(&tcb_list, tcbelm, next); } #ifdef TLS_VARIANT_I /* * Return pointer to allocated TLS block */ static void * get_tls_block_ptr(void *tcb, size_t tcbsize) { size_t extra_size, post_size, pre_size, tls_block_size; size_t tls_init_align; tls_init_align = MAX(obj_main->tlsalign, 1); /* Compute fragments sizes. */ extra_size = tcbsize - TLS_TCB_SIZE; post_size = calculate_tls_post_size(tls_init_align); tls_block_size = tcbsize + post_size; pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; return ((char *)tcb - pre_size - extra_size); } /* * Allocate Static TLS using the Variant I method. * * For details on the layout, see lib/libc/gen/tls.c. * * NB: rtld's tls_static_space variable includes TLS_TCB_SIZE and post_size as * it is based on tls_last_offset, and TLS offsets here are really TCB * offsets, whereas libc's tls_static_space is just the executable's static * TLS segment. * * NB: This differs from NetBSD's ld.elf_so, where TLS offsets are relative to * the end of the TCB. */ void * allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) { Obj_Entry *obj; char *tls_block; struct dtv *dtv; struct tcb *tcb; char *addr; size_t i; size_t extra_size, maxalign, post_size, pre_size, tls_block_size; size_t tls_init_align, tls_init_offset, tls_bss_offset; if (oldtcb != NULL && tcbsize == TLS_TCB_SIZE) return (oldtcb); assert(tcbsize >= TLS_TCB_SIZE); maxalign = MAX(tcbalign, tls_static_max_align); tls_init_align = MAX(obj_main->tlsalign, 1); /* Compute fragments sizes. */ extra_size = tcbsize - TLS_TCB_SIZE; post_size = calculate_tls_post_size(tls_init_align); tls_block_size = tcbsize + post_size; pre_size = roundup2(tls_block_size, tls_init_align) - tls_block_size; tls_block_size += pre_size + tls_static_space - TLS_TCB_SIZE - post_size; /* Allocate whole TLS block */ tls_block = xmalloc_aligned(tls_block_size, maxalign, 0); tcb = (struct tcb *)(tls_block + pre_size + extra_size); if (oldtcb != NULL) { memcpy(tls_block, get_tls_block_ptr(oldtcb, tcbsize), tls_static_space); free(get_tls_block_ptr(oldtcb, tcbsize)); /* Adjust the DTV. */ dtv = tcb->tcb_dtv; for (i = 0; i < dtv->dtv_size; i++) { if ((uintptr_t)dtv->dtv_slots[i].dtvs_tls >= (uintptr_t)oldtcb && (uintptr_t)dtv->dtv_slots[i].dtvs_tls < (uintptr_t)oldtcb + tls_static_space) { dtv->dtv_slots[i].dtvs_tls = (char *)tcb + (dtv->dtv_slots[i].dtvs_tls - (char *)oldtcb); } } } else { dtv = xcalloc(1, sizeof(struct dtv) + tls_max_index * sizeof(struct dtv_slot)); tcb->tcb_dtv = dtv; dtv->dtv_gen = tls_dtv_generation; dtv->dtv_size = tls_max_index; for (obj = globallist_curr(objs); obj != NULL; obj = globallist_next(obj)) { if (obj->tlsoffset == 0) continue; tls_init_offset = obj->tlspoffset & (obj->tlsalign - 1); addr = (char *)tcb + obj->tlsoffset; if (tls_init_offset > 0) memset(addr, 0, tls_init_offset); if (obj->tlsinitsize > 0) { memcpy(addr + tls_init_offset, obj->tlsinit, obj->tlsinitsize); } if (obj->tlssize > obj->tlsinitsize) { tls_bss_offset = tls_init_offset + obj->tlsinitsize; memset(addr + tls_bss_offset, 0, obj->tlssize - tls_bss_offset); } dtv->dtv_slots[obj->tlsindex - 1].dtvs_tls = addr; } } tcb_list_insert(tcb); return (tcb); } void free_tls(void *tcb, size_t tcbsize, size_t tcbalign __unused) { struct dtv *dtv; uintptr_t tlsstart, tlsend; size_t post_size; size_t i, tls_init_align __unused; tcb_list_remove(tcb); assert(tcbsize >= TLS_TCB_SIZE); tls_init_align = MAX(obj_main->tlsalign, 1); /* Compute fragments sizes. */ post_size = calculate_tls_post_size(tls_init_align); tlsstart = (uintptr_t)tcb + TLS_TCB_SIZE + post_size; tlsend = (uintptr_t)tcb + tls_static_space; dtv = ((struct tcb *)tcb)->tcb_dtv; for (i = 0; i < dtv->dtv_size; i++) { if (dtv->dtv_slots[i].dtvs_tls != NULL && ((uintptr_t)dtv->dtv_slots[i].dtvs_tls < tlsstart || (uintptr_t)dtv->dtv_slots[i].dtvs_tls >= tlsend)) { free(dtv->dtv_slots[i].dtvs_tls); } } free(dtv); free(get_tls_block_ptr(tcb, tcbsize)); } #endif /* TLS_VARIANT_I */ #ifdef TLS_VARIANT_II /* * Allocate Static TLS using the Variant II method. */ void * allocate_tls(Obj_Entry *objs, void *oldtcb, size_t tcbsize, size_t tcbalign) { Obj_Entry *obj; size_t size, ralign; char *tls_block; struct dtv *dtv, *olddtv; struct tcb *tcb; char *addr; size_t i; ralign = tcbalign; if (tls_static_max_align > ralign) ralign = tls_static_max_align; size = roundup(tls_static_space, ralign) + roundup(tcbsize, ralign); assert(tcbsize >= 2 * sizeof(uintptr_t)); tls_block = xmalloc_aligned(size, ralign, 0 /* XXX */); dtv = xcalloc(1, sizeof(struct dtv) + tls_max_index * sizeof(struct dtv_slot)); tcb = (struct tcb *)(tls_block + roundup(tls_static_space, ralign)); tcb->tcb_self = tcb; tcb->tcb_dtv = dtv; dtv->dtv_gen = tls_dtv_generation; dtv->dtv_size = tls_max_index; if (oldtcb != NULL) { /* * Copy the static TLS block over whole. */ memcpy((char *)tcb - tls_static_space, (const char *)oldtcb - tls_static_space, tls_static_space); /* * If any dynamic TLS blocks have been created tls_get_addr(), * move them over. */ olddtv = ((struct tcb *)oldtcb)->tcb_dtv; for (i = 0; i < olddtv->dtv_size; i++) { if ((uintptr_t)olddtv->dtv_slots[i].dtvs_tls < (uintptr_t)oldtcb - size || (uintptr_t)olddtv->dtv_slots[i].dtvs_tls > (uintptr_t)oldtcb) { dtv->dtv_slots[i].dtvs_tls = olddtv->dtv_slots[i].dtvs_tls; olddtv->dtv_slots[i].dtvs_tls = NULL; } } /* * We assume that this block was the one we created with * allocate_initial_tls(). */ free_tls(oldtcb, 2 * sizeof(uintptr_t), sizeof(uintptr_t)); } else { for (obj = objs; obj != NULL; obj = TAILQ_NEXT(obj, next)) { if (obj->marker || obj->tlsoffset == 0) continue; addr = (char *)tcb - obj->tlsoffset; memset(addr + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); if (obj->tlsinit) { memcpy(addr, obj->tlsinit, obj->tlsinitsize); obj->static_tls_copied = true; } dtv->dtv_slots[obj->tlsindex - 1].dtvs_tls = addr; } } tcb_list_insert(tcb); return (tcb); } void free_tls(void *tcb, size_t tcbsize __unused, size_t tcbalign) { struct dtv *dtv; size_t size, ralign; size_t i; uintptr_t tlsstart, tlsend; tcb_list_remove(tcb); /* * Figure out the size of the initial TLS block so that we can * find stuff which ___tls_get_addr() allocated dynamically. */ ralign = tcbalign; if (tls_static_max_align > ralign) ralign = tls_static_max_align; size = roundup(tls_static_space, ralign); dtv = ((struct tcb *)tcb)->tcb_dtv; tlsend = (uintptr_t)tcb; tlsstart = tlsend - size; for (i = 0; i < dtv->dtv_size; i++) { if (dtv->dtv_slots[i].dtvs_tls != NULL && ((uintptr_t)dtv->dtv_slots[i].dtvs_tls < tlsstart || (uintptr_t)dtv->dtv_slots[i].dtvs_tls > tlsend)) { free(dtv->dtv_slots[i].dtvs_tls); } } free((void *)tlsstart); free(dtv); } #endif /* TLS_VARIANT_II */ /* * Allocate TLS block for module with given index. */ void * allocate_module_tls(struct tcb *tcb, int index) { Obj_Entry *obj; char *p; TAILQ_FOREACH(obj, &obj_list, next) { if (obj->marker) continue; if (obj->tlsindex == index) break; } if (obj == NULL) { _rtld_error("Can't find module with TLS index %d", index); rtld_die(); } if (obj->tls_static) { #ifdef TLS_VARIANT_I p = (char *)tcb + obj->tlsoffset; #else p = (char *)tcb - obj->tlsoffset; #endif return (p); } obj->tls_dynamic = true; p = xmalloc_aligned(obj->tlssize, obj->tlsalign, obj->tlspoffset); memcpy(p, obj->tlsinit, obj->tlsinitsize); memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); return (p); } static bool allocate_tls_offset_common(size_t *offp, size_t tlssize, size_t tlsalign, size_t tlspoffset __unused) { size_t off; if (tls_last_offset == 0) off = calculate_first_tls_offset(tlssize, tlsalign, tlspoffset); else off = calculate_tls_offset(tls_last_offset, tls_last_size, tlssize, tlsalign, tlspoffset); *offp = off; #ifdef TLS_VARIANT_I off += tlssize; #endif /* * If we have already fixed the size of the static TLS block, we * must stay within that size. When allocating the static TLS, we * leave a small amount of space spare to be used for dynamically * loading modules which use static TLS. */ if (tls_static_space != 0) { if (off > tls_static_space) return (false); } else if (tlsalign > tls_static_max_align) { tls_static_max_align = tlsalign; } tls_last_offset = off; tls_last_size = tlssize; return (true); } bool allocate_tls_offset(Obj_Entry *obj) { if (obj->tls_dynamic) return (false); if (obj->tls_static) return (true); if (obj->tlssize == 0) { obj->tls_static = true; return (true); } if (!allocate_tls_offset_common(&obj->tlsoffset, obj->tlssize, obj->tlsalign, obj->tlspoffset)) return (false); obj->tls_static = true; return (true); } void free_tls_offset(Obj_Entry *obj) { /* * If we were the last thing to allocate out of the static TLS * block, we give our space back to the 'allocator'. This is a * simplistic workaround to allow libGL.so.1 to be loaded and * unloaded multiple times. */ size_t off = obj->tlsoffset; #ifdef TLS_VARIANT_I off += obj->tlssize; #endif if (off == tls_last_offset) { tls_last_offset -= obj->tlssize; tls_last_size = 0; } } void * _rtld_allocate_tls(void *oldtcb, size_t tcbsize, size_t tcbalign) { void *ret; RtldLockState lockstate; wlock_acquire(rtld_bind_lock, &lockstate); ret = allocate_tls(globallist_curr(TAILQ_FIRST(&obj_list)), oldtcb, tcbsize, tcbalign); lock_release(rtld_bind_lock, &lockstate); return (ret); } void _rtld_free_tls(void *tcb, size_t tcbsize, size_t tcbalign) { RtldLockState lockstate; wlock_acquire(rtld_bind_lock, &lockstate); free_tls(tcb, tcbsize, tcbalign); lock_release(rtld_bind_lock, &lockstate); } static void object_add_name(Obj_Entry *obj, const char *name) { Name_Entry *entry; size_t len; len = strlen(name); entry = malloc(sizeof(Name_Entry) + len); if (entry != NULL) { strcpy(entry->name, name); STAILQ_INSERT_TAIL(&obj->names, entry, link); } } static int object_match_name(const Obj_Entry *obj, const char *name) { Name_Entry *entry; STAILQ_FOREACH(entry, &obj->names, link) { if (strcmp(name, entry->name) == 0) return (1); } return (0); } static Obj_Entry * locate_dependency(const Obj_Entry *obj, const char *name) { const Objlist_Entry *entry; const Needed_Entry *needed; STAILQ_FOREACH(entry, &list_main, link) { if (object_match_name(entry->obj, name)) return (entry->obj); } for (needed = obj->needed; needed != NULL; needed = needed->next) { if (strcmp(obj->strtab + needed->name, name) == 0 || (needed->obj != NULL && object_match_name(needed->obj, name))) { /* * If there is DT_NEEDED for the name we are looking * for, we are all set. Note that object might not be * found if dependency was not loaded yet, so the * function can return NULL here. This is expected and * handled properly by the caller. */ return (needed->obj); } } _rtld_error("%s: Unexpected inconsistency: dependency %s not found", obj->path, name); rtld_die(); } static int check_object_provided_version(Obj_Entry *refobj, const Obj_Entry *depobj, const Elf_Vernaux *vna) { const Elf_Verdef *vd; const char *vername; vername = refobj->strtab + vna->vna_name; vd = depobj->verdef; if (vd == NULL) { _rtld_error("%s: version %s required by %s not defined", depobj->path, vername, refobj->path); return (-1); } for (;;) { if (vd->vd_version != VER_DEF_CURRENT) { _rtld_error( "%s: Unsupported version %d of Elf_Verdef entry", depobj->path, vd->vd_version); return (-1); } if (vna->vna_hash == vd->vd_hash) { const Elf_Verdaux *aux = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); if (strcmp(vername, depobj->strtab + aux->vda_name) == 0) return (0); } if (vd->vd_next == 0) break; vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); } if (vna->vna_flags & VER_FLG_WEAK) return (0); _rtld_error("%s: version %s required by %s not found", depobj->path, vername, refobj->path); return (-1); } static int rtld_verify_object_versions(Obj_Entry *obj) { const Elf_Verneed *vn; const Elf_Verdef *vd; const Elf_Verdaux *vda; const Elf_Vernaux *vna; const Obj_Entry *depobj; int maxvernum, vernum; if (obj->ver_checked) return (0); obj->ver_checked = true; maxvernum = 0; /* * Walk over defined and required version records and figure out * max index used by any of them. Do very basic sanity checking * while there. */ vn = obj->verneed; while (vn != NULL) { if (vn->vn_version != VER_NEED_CURRENT) { _rtld_error( "%s: Unsupported version %d of Elf_Verneed entry", obj->path, vn->vn_version); return (-1); } vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); for (;;) { vernum = VER_NEED_IDX(vna->vna_other); if (vernum > maxvernum) maxvernum = vernum; if (vna->vna_next == 0) break; vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); } if (vn->vn_next == 0) break; vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); } vd = obj->verdef; while (vd != NULL) { if (vd->vd_version != VER_DEF_CURRENT) { _rtld_error( "%s: Unsupported version %d of Elf_Verdef entry", obj->path, vd->vd_version); return (-1); } vernum = VER_DEF_IDX(vd->vd_ndx); if (vernum > maxvernum) maxvernum = vernum; if (vd->vd_next == 0) break; vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); } if (maxvernum == 0) return (0); /* * Store version information in array indexable by version index. * Verify that object version requirements are satisfied along the * way. */ obj->vernum = maxvernum + 1; obj->vertab = xcalloc(obj->vernum, sizeof(Ver_Entry)); vd = obj->verdef; while (vd != NULL) { if ((vd->vd_flags & VER_FLG_BASE) == 0) { vernum = VER_DEF_IDX(vd->vd_ndx); assert(vernum <= maxvernum); vda = (const Elf_Verdaux *)((const char *)vd + vd->vd_aux); obj->vertab[vernum].hash = vd->vd_hash; obj->vertab[vernum].name = obj->strtab + vda->vda_name; obj->vertab[vernum].file = NULL; obj->vertab[vernum].flags = 0; } if (vd->vd_next == 0) break; vd = (const Elf_Verdef *)((const char *)vd + vd->vd_next); } vn = obj->verneed; while (vn != NULL) { depobj = locate_dependency(obj, obj->strtab + vn->vn_file); if (depobj == NULL) return (-1); vna = (const Elf_Vernaux *)((const char *)vn + vn->vn_aux); for (;;) { if (check_object_provided_version(obj, depobj, vna)) return (-1); vernum = VER_NEED_IDX(vna->vna_other); assert(vernum <= maxvernum); obj->vertab[vernum].hash = vna->vna_hash; obj->vertab[vernum].name = obj->strtab + vna->vna_name; obj->vertab[vernum].file = obj->strtab + vn->vn_file; obj->vertab[vernum].flags = (vna->vna_other & VER_NEED_HIDDEN) != 0 ? VER_INFO_HIDDEN : 0; if (vna->vna_next == 0) break; vna = (const Elf_Vernaux *)((const char *)vna + vna->vna_next); } if (vn->vn_next == 0) break; vn = (const Elf_Verneed *)((const char *)vn + vn->vn_next); } return (0); } static int rtld_verify_versions(const Objlist *objlist) { Objlist_Entry *entry; int rc; rc = 0; STAILQ_FOREACH(entry, objlist, link) { /* * Skip dummy objects or objects that have their version * requirements already checked. */ if (entry->obj->strtab == NULL || entry->obj->vertab != NULL) continue; if (rtld_verify_object_versions(entry->obj) == -1) { rc = -1; if (ld_tracing == NULL) break; } } if (rc == 0 || ld_tracing != NULL) rc = rtld_verify_object_versions(&obj_rtld); return (rc); } const Ver_Entry * fetch_ventry(const Obj_Entry *obj, unsigned long symnum) { Elf_Versym vernum; if (obj->vertab) { vernum = VER_NDX(obj->versyms[symnum]); if (vernum >= obj->vernum) { _rtld_error("%s: symbol %s has wrong verneed value %d", obj->path, obj->strtab + symnum, vernum); } else if (obj->vertab[vernum].hash != 0) { return (&obj->vertab[vernum]); } } return (NULL); } int _rtld_get_stack_prot(void) { return (stack_prot); } int _rtld_is_dlopened(void *arg) { Obj_Entry *obj; RtldLockState lockstate; int res; rlock_acquire(rtld_bind_lock, &lockstate); obj = dlcheck(arg); if (obj == NULL) obj = obj_from_addr(arg); if (obj == NULL) { _rtld_error("No shared object contains address"); lock_release(rtld_bind_lock, &lockstate); return (-1); } res = obj->dlopened ? 1 : 0; lock_release(rtld_bind_lock, &lockstate); return (res); } static int obj_remap_relro(Obj_Entry *obj, int prot) { const Elf_Phdr *ph; caddr_t relro_page; size_t relro_size; for (ph = obj->phdr; ph < obj->phdr + obj->phnum; ph++) { if (ph->p_type != PT_GNU_RELRO) continue; relro_page = obj->relocbase + rtld_trunc_page(ph->p_vaddr); relro_size = rtld_round_page(ph->p_vaddr + ph->p_memsz) - rtld_trunc_page(ph->p_vaddr); if (mprotect(relro_page, relro_size, prot) == -1) { _rtld_error( "%s: Cannot set relro protection to %#x: %s", obj->path, prot, rtld_strerror(errno)); return (-1); } break; } return (0); } static int obj_disable_relro(Obj_Entry *obj) { return (obj_remap_relro(obj, PROT_READ | PROT_WRITE)); } static int obj_enforce_relro(Obj_Entry *obj) { return (obj_remap_relro(obj, PROT_READ)); } static void map_stacks_exec(RtldLockState *lockstate) { void (*thr_map_stacks_exec)(void); if ((max_stack_flags & PF_X) == 0 || (stack_prot & PROT_EXEC) != 0) return; thr_map_stacks_exec = (void (*)(void))( uintptr_t)get_program_var_addr("__pthread_map_stacks_exec", lockstate); if (thr_map_stacks_exec != NULL) { stack_prot |= PROT_EXEC; thr_map_stacks_exec(); } } static void distribute_static_tls(Objlist *list) { struct tcb_list_entry *tcbelm; Objlist_Entry *objelm; struct tcb *tcb; Obj_Entry *obj; char *tlsbase; STAILQ_FOREACH(objelm, list, link) { obj = objelm->obj; if (obj->marker || !obj->tls_static || obj->static_tls_copied) continue; TAILQ_FOREACH(tcbelm, &tcb_list, next) { tcb = tcb_from_tcb_list_entry(tcbelm); #ifdef TLS_VARIANT_I tlsbase = (char *)tcb + obj->tlsoffset; #else tlsbase = (char *)tcb - obj->tlsoffset; #endif memcpy(tlsbase, obj->tlsinit, obj->tlsinitsize); memset(tlsbase + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize); } obj->static_tls_copied = true; } } void symlook_init(SymLook *dst, const char *name) { bzero(dst, sizeof(*dst)); dst->name = name; dst->hash = elf_hash(name); dst->hash_gnu = gnu_hash(name); } static void symlook_init_from_req(SymLook *dst, const SymLook *src) { dst->name = src->name; dst->hash = src->hash; dst->hash_gnu = src->hash_gnu; dst->ventry = src->ventry; dst->flags = src->flags; dst->defobj_out = NULL; dst->sym_out = NULL; dst->lockstate = src->lockstate; } static int open_binary_fd(const char *argv0, bool search_in_path, const char **binpath_res) { char *binpath, *pathenv, *pe, *res1; const char *res; int fd; binpath = NULL; res = NULL; if (search_in_path && strchr(argv0, '/') == NULL) { binpath = xmalloc(PATH_MAX); pathenv = getenv("PATH"); if (pathenv == NULL) { _rtld_error("-p and no PATH environment variable"); rtld_die(); } pathenv = strdup(pathenv); if (pathenv == NULL) { _rtld_error("Cannot allocate memory"); rtld_die(); } fd = -1; errno = ENOENT; while ((pe = strsep(&pathenv, ":")) != NULL) { if (strlcpy(binpath, pe, PATH_MAX) >= PATH_MAX) continue; if (binpath[0] != '\0' && strlcat(binpath, "/", PATH_MAX) >= PATH_MAX) continue; if (strlcat(binpath, argv0, PATH_MAX) >= PATH_MAX) continue; fd = open(binpath, O_RDONLY | O_CLOEXEC | O_VERIFY); if (fd != -1 || errno != ENOENT) { res = binpath; break; } } free(pathenv); } else { fd = open(argv0, O_RDONLY | O_CLOEXEC | O_VERIFY); res = argv0; } if (fd == -1) { _rtld_error("Cannot open %s: %s", argv0, rtld_strerror(errno)); rtld_die(); } if (res != NULL && res[0] != '/') { res1 = xmalloc(PATH_MAX); if (realpath(res, res1) != NULL) { if (res != argv0) free(__DECONST(char *, res)); res = res1; } else { free(res1); } } *binpath_res = res; return (fd); } /* * Parse a set of command-line arguments. */ static int parse_args(char *argv[], int argc, bool *use_pathp, int *fdp, const char **argv0, bool *dir_ignore) { const char *arg; char machine[64]; size_t sz; int arglen, fd, i, j, mib[2]; char opt; bool seen_b, seen_f; dbg("Parsing command-line arguments"); *use_pathp = false; *fdp = -1; *dir_ignore = false; seen_b = seen_f = false; for (i = 1; i < argc; i++) { arg = argv[i]; dbg("argv[%d]: '%s'", i, arg); /* * rtld arguments end with an explicit "--" or with the first * non-prefixed argument. */ if (strcmp(arg, "--") == 0) { i++; break; } if (arg[0] != '-') break; /* * All other arguments are single-character options that can * be combined, so we need to search through `arg` for them. */ arglen = strlen(arg); for (j = 1; j < arglen; j++) { opt = arg[j]; if (opt == 'h') { print_usage(argv[0]); _exit(0); } else if (opt == 'b') { if (seen_f) { _rtld_error("Both -b and -f specified"); rtld_die(); } if (j != arglen - 1) { _rtld_error("Invalid options: %s", arg); rtld_die(); } i++; *argv0 = argv[i]; seen_b = true; break; } else if (opt == 'd') { *dir_ignore = true; } else if (opt == 'f') { if (seen_b) { _rtld_error("Both -b and -f specified"); rtld_die(); } /* * -f XX can be used to specify a * descriptor for the binary named at * the command line (i.e., the later * argument will specify the process * name but the descriptor is what * will actually be executed). * * -f must be the last option in the * group, e.g., -abcf . */ if (j != arglen - 1) { _rtld_error("Invalid options: %s", arg); rtld_die(); } i++; fd = parse_integer(argv[i]); if (fd == -1) { _rtld_error( "Invalid file descriptor: '%s'", argv[i]); rtld_die(); } *fdp = fd; seen_f = true; break; } else if (opt == 'o') { struct ld_env_var_desc *l; char *n, *v; u_int ll; if (j != arglen - 1) { _rtld_error("Invalid options: %s", arg); rtld_die(); } i++; n = argv[i]; v = strchr(n, '='); if (v == NULL) { _rtld_error("No '=' in -o parameter"); rtld_die(); } for (ll = 0; ll < nitems(ld_env_vars); ll++) { l = &ld_env_vars[ll]; if (v - n == (ptrdiff_t)strlen(l->n) && strncmp(n, l->n, v - n) == 0) { l->val = v + 1; break; } } if (ll == nitems(ld_env_vars)) { _rtld_error("Unknown LD_ option %s", n); rtld_die(); } } else if (opt == 'p') { *use_pathp = true; } else if (opt == 'u') { u_int ll; for (ll = 0; ll < nitems(ld_env_vars); ll++) ld_env_vars[ll].val = NULL; } else if (opt == 'v') { machine[0] = '\0'; mib[0] = CTL_HW; mib[1] = HW_MACHINE; sz = sizeof(machine); sysctl(mib, nitems(mib), machine, &sz, NULL, 0); ld_elf_hints_path = ld_get_env_var( LD_ELF_HINTS_PATH); set_ld_elf_hints_path(); rtld_printf( "FreeBSD ld-elf.so.1 %s\n" "FreeBSD_version %d\n" "Default lib path %s\n" "Hints lib path %s\n" "Env prefix %s\n" "Default hint file %s\n" "Hint file %s\n" "libmap file %s\n" "Optional static TLS size %zd bytes\n", machine, __FreeBSD_version, ld_standard_library_path, gethints(false), ld_env_prefix, ld_elf_hints_default, ld_elf_hints_path, ld_path_libmap_conf, ld_static_tls_extra); _exit(0); } else { _rtld_error("Invalid argument: '%s'", arg); print_usage(argv[0]); rtld_die(); } } } if (!seen_b) *argv0 = argv[i]; return (i); } /* * Parse a file descriptor number without pulling in more of libc (e.g. atoi). */ static int parse_integer(const char *str) { static const int RADIX = 10; /* XXXJA: possibly support hex? */ const char *orig; int n; char c; orig = str; n = 0; for (c = *str; c != '\0'; c = *++str) { if (c < '0' || c > '9') return (-1); if (n > INT_MAX / RADIX) return (-1); n *= RADIX; if (n > INT_MAX - (c - '0')) return (-1); n += c - '0'; } /* Make sure we actually parsed something. */ if (str == orig) return (-1); return (n); } static void print_usage(const char *argv0) { rtld_printf( "Usage: %s [-h] [-b ] [-d] [-f ] [-p] [--] []\n" "\n" "Options:\n" " -h Display this help message\n" " -b Execute instead of , arg0 is \n" " -d Ignore lack of exec permissions for the binary\n" " -f Execute instead of searching for \n" " -o = Set LD_ to , without polluting env\n" " -p Search in PATH for named binary\n" " -u Ignore LD_ environment variables\n" " -v Display identification information\n" " -- End of RTLD options\n" " Name of process to execute\n" " Arguments to the executed process\n", argv0); } #define AUXFMT(at, xfmt) [at] = { .name = #at, .fmt = xfmt } static const struct auxfmt { const char *name; const char *fmt; } auxfmts[] = { AUXFMT(AT_NULL, NULL), AUXFMT(AT_IGNORE, NULL), AUXFMT(AT_EXECFD, "%ld"), AUXFMT(AT_PHDR, "%p"), AUXFMT(AT_PHENT, "%lu"), AUXFMT(AT_PHNUM, "%lu"), AUXFMT(AT_PAGESZ, "%lu"), AUXFMT(AT_BASE, "%#lx"), AUXFMT(AT_FLAGS, "%#lx"), AUXFMT(AT_ENTRY, "%p"), AUXFMT(AT_NOTELF, NULL), AUXFMT(AT_UID, "%ld"), AUXFMT(AT_EUID, "%ld"), AUXFMT(AT_GID, "%ld"), AUXFMT(AT_EGID, "%ld"), AUXFMT(AT_EXECPATH, "%s"), AUXFMT(AT_CANARY, "%p"), AUXFMT(AT_CANARYLEN, "%lu"), AUXFMT(AT_OSRELDATE, "%lu"), AUXFMT(AT_NCPUS, "%lu"), AUXFMT(AT_PAGESIZES, "%p"), AUXFMT(AT_PAGESIZESLEN, "%lu"), AUXFMT(AT_TIMEKEEP, "%p"), AUXFMT(AT_STACKPROT, "%#lx"), AUXFMT(AT_EHDRFLAGS, "%#lx"), AUXFMT(AT_HWCAP, "%#lx"), AUXFMT(AT_HWCAP2, "%#lx"), AUXFMT(AT_BSDFLAGS, "%#lx"), AUXFMT(AT_ARGC, "%lu"), AUXFMT(AT_ARGV, "%p"), AUXFMT(AT_ENVC, "%p"), AUXFMT(AT_ENVV, "%p"), AUXFMT(AT_PS_STRINGS, "%p"), AUXFMT(AT_FXRNG, "%p"), AUXFMT(AT_KPRELOAD, "%p"), AUXFMT(AT_USRSTACKBASE, "%#lx"), AUXFMT(AT_USRSTACKLIM, "%#lx"), /* AT_CHERI_STATS */ AUXFMT(AT_HWCAP3, "%#lx"), AUXFMT(AT_HWCAP4, "%#lx"), }; static bool is_ptr_fmt(const char *fmt) { char last; last = fmt[strlen(fmt) - 1]; return (last == 'p' || last == 's'); } static void dump_auxv(Elf_Auxinfo **aux_info) { Elf_Auxinfo *auxp; const struct auxfmt *fmt; int i; for (i = 0; i < AT_COUNT; i++) { auxp = aux_info[i]; if (auxp == NULL) continue; fmt = &auxfmts[i]; if (fmt->fmt == NULL) continue; rtld_fdprintf(STDOUT_FILENO, "%s:\t", fmt->name); if (is_ptr_fmt(fmt->fmt)) { rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, auxp->a_un.a_ptr); } else { rtld_fdprintfx(STDOUT_FILENO, fmt->fmt, auxp->a_un.a_val); } rtld_fdprintf(STDOUT_FILENO, "\n"); } } const char * rtld_get_var(const char *name) { const struct ld_env_var_desc *lvd; u_int i; for (i = 0; i < nitems(ld_env_vars); i++) { lvd = &ld_env_vars[i]; if (strcmp(lvd->n, name) == 0) return (lvd->val); } return (NULL); } static void rtld_recalc_dangerous_ld_env(void) { /* * Never reset dangerous_ld_env back to false if rtld was ever * contaminated with it set to true. */ dangerous_ld_env |= libmap_disable || libmap_override != NULL || ld_library_path != NULL || ld_preload != NULL || ld_elf_hints_path != NULL || ld_loadfltr || !ld_dynamic_weak || ld_get_env_var(LD_STATIC_TLS_EXTRA) != NULL; } static void rtld_recalc_debug(const char *ld_debug) { if (ld_debug != NULL && *ld_debug != '\0') debug = 1; } static void rtld_set_var_debug(struct ld_env_var_desc *lvd) { rtld_recalc_debug(lvd->val); } static void rtld_set_var_library_path(struct ld_env_var_desc *lvd) { ld_library_path = lvd->val; } static void rtld_set_var_library_path_fds(struct ld_env_var_desc *lvd) { ld_library_dirs = lvd->val; } static void rtld_recalc_path_rpath(const char *library_path_rpath) { if (library_path_rpath != NULL) { if (library_path_rpath[0] == 'y' || library_path_rpath[0] == 'Y' || library_path_rpath[0] == '1') ld_library_path_rpath = true; else ld_library_path_rpath = false; } else { ld_library_path_rpath = false; } } static void rtld_set_var_library_path_rpath(struct ld_env_var_desc *lvd) { rtld_recalc_path_rpath(lvd->val); } static void rtld_recalc_bind_not(const char *bind_not_val) { if (ld_bind_now == NULL) ld_bind_not = bind_not_val != NULL; } static void rtld_set_var_bind_now(struct ld_env_var_desc *lvd) { ld_bind_now = lvd->val; rtld_recalc_bind_not(ld_get_env_var(LD_BIND_NOT)); } static void rtld_set_var_bind_not(struct ld_env_var_desc *lvd) { rtld_recalc_bind_not(lvd->val); } static void rtld_set_var_dynamic_weak(struct ld_env_var_desc *lvd) { ld_dynamic_weak = lvd->val == NULL; } static void rtld_set_var_loadfltr(struct ld_env_var_desc *lvd) { ld_loadfltr = lvd->val != NULL; } static void rtld_set_var_libmap_disable(struct ld_env_var_desc *lvd) { libmap_disable = lvd->val != NULL; } int rtld_set_var(const char *name, const char *val) { RtldLockState lockstate; struct ld_env_var_desc *lvd; u_int i; int error; error = ENOENT; wlock_acquire(rtld_bind_lock, &lockstate); for (i = 0; i < nitems(ld_env_vars); i++) { lvd = &ld_env_vars[i]; if (strcmp(lvd->n, name) != 0) continue; if (!lvd->can_update || (lvd->unsecure && !trust)) { error = EPERM; break; } if (lvd->owned) free(__DECONST(char *, lvd->val)); if (val != NULL) lvd->val = xstrdup(val); else lvd->val = NULL; lvd->owned = true; if (lvd->on_update != NULL) lvd->on_update(lvd); error = 0; break; } if (error == 0) rtld_recalc_dangerous_ld_env(); lock_release(rtld_bind_lock, &lockstate); return (error); } /* * Overrides for libc_pic-provided functions. */ int __getosreldate(void) { size_t len; int oid[2]; int error, osrel; if (osreldate != 0) return (osreldate); oid[0] = CTL_KERN; oid[1] = KERN_OSRELDATE; osrel = 0; len = sizeof(osrel); error = sysctl(oid, 2, &osrel, &len, NULL, 0); if (error == 0 && osrel > 0 && len == sizeof(osrel)) osreldate = osrel; return (osreldate); } const char * rtld_strerror(int errnum) { if (errnum < 0 || errnum >= sys_nerr) return ("Unknown error"); return (sys_errlist[errnum]); } char * getenv(const char *name) { return (__DECONST(char *, rtld_get_env_val(environ, name, strlen(name)))); } /* malloc */ void * malloc(size_t nbytes) { return (__crt_malloc(nbytes)); } void * calloc(size_t num, size_t size) { return (__crt_calloc(num, size)); } void free(void *cp) { __crt_free(cp); } void * realloc(void *cp, size_t nbytes) { return (__crt_realloc(cp, nbytes)); } extern int _rtld_version__FreeBSD_version __exported; int _rtld_version__FreeBSD_version = __FreeBSD_version; extern char _rtld_version_laddr_offset __exported; char _rtld_version_laddr_offset; extern char _rtld_version_dlpi_tls_data __exported; char _rtld_version_dlpi_tls_data;