/* LibTomCrypt, modular cryptographic library -- Tom St Denis */
/* SPDX-License-Identifier: Unlicense */
#include "tomcrypt_private.h"

/**
  @file pem.c
  Const declarations for PEM, Steffen Jaeckel
*/

#ifdef LTC_PEM

const struct pem_header_id pem_std_headers[] = {
   {
     /* X.509 Certificates */
     SET_CSTR(.start, "-----BEGIN CERTIFICATE-----"),
     SET_CSTR(.end, "-----END CERTIFICATE-----"),
     .has_more_headers = no,
     .flags = pf_x509,
   },
   {
     /* PKCS#8 encrypted */
     SET_CSTR(.start, "-----BEGIN ENCRYPTED PRIVATE KEY-----"),
     SET_CSTR(.end, "-----END ENCRYPTED PRIVATE KEY-----"),
     .has_more_headers = no,
     .flags = pf_encrypted_pkcs8,
   },
   {
     /* PKCS#8 plain */
     SET_CSTR(.start, "-----BEGIN PRIVATE KEY-----"),
     SET_CSTR(.end, "-----END PRIVATE KEY-----"),
     .has_more_headers = no,
     .flags = pf_pkcs8,
   },
   {
     /* Regular (plain) public keys */
     SET_CSTR(.start, "-----BEGIN PUBLIC KEY-----"),
     SET_CSTR(.end, "-----END PUBLIC KEY-----"),
     .has_more_headers = no,
     .flags = pf_public,
   },
   {
     SET_CSTR(.start, "-----BEGIN RSA PUBLIC KEY-----"),
     SET_CSTR(.end, "-----END RSA PUBLIC KEY-----"),
     .has_more_headers = no,
     .pka = LTC_PKA_RSA,
     .flags = pf_public,
   },
   /* Regular plain or encrypted private keys */
   {
     SET_CSTR(.start, "-----BEGIN RSA PRIVATE KEY-----"),
     SET_CSTR(.end, "-----END RSA PRIVATE KEY-----"),
     .has_more_headers = maybe,
     .pka = LTC_PKA_RSA,
   },
   {
     SET_CSTR(.start, "-----BEGIN EC PRIVATE KEY-----"),
     SET_CSTR(.end, "-----END EC PRIVATE KEY-----"),
     .has_more_headers = maybe,
     .pka = LTC_PKA_EC,
   },
   {
     SET_CSTR(.start, "-----BEGIN DSA PRIVATE KEY-----"),
     SET_CSTR(.end, "-----END DSA PRIVATE KEY-----"),
     .has_more_headers = maybe,
     .pka = LTC_PKA_DSA,
   },
};
const unsigned long pem_std_headers_num = LTC_ARRAY_SIZE(pem_std_headers);

/* Encrypted PEM files */
const struct str pem_proc_type_encrypted = { SET_CSTR(, "Proc-Type: 4,ENCRYPTED") };
#if defined(LTC_SSH)
const struct str pem_ssh_comment = { SET_CSTR(, "Comment: ") };
#endif
const struct str pem_dek_info_start = { SET_CSTR(, "DEK-Info: ") };
const struct blockcipher_info pem_dek_infos[] =
   {
      { .name = "AES-128-CBC,",       .algo = "aes",      .keylen = 128 / 8, .mode = cm_cbc,    },
      { .name = "AES-192-CBC,",       .algo = "aes",      .keylen = 192 / 8, .mode = cm_cbc,    },
      { .name = "AES-256-CBC,",       .algo = "aes",      .keylen = 256 / 8, .mode = cm_cbc,    },
      { .name = "AES-128-CFB,",       .algo = "aes",      .keylen = 128 / 8, .mode = cm_cfb,    },
      { .name = "AES-192-CFB,",       .algo = "aes",      .keylen = 192 / 8, .mode = cm_cfb,    },
      { .name = "AES-256-CFB,",       .algo = "aes",      .keylen = 256 / 8, .mode = cm_cfb,    },
      { .name = "AES-128-CFB1,",      .algo = "aes",      .keylen = 128 / 8, .mode = cm_cfb1,   },
      { .name = "AES-192-CFB1,",      .algo = "aes",      .keylen = 192 / 8, .mode = cm_cfb1,   },
      { .name = "AES-256-CFB1,",      .algo = "aes",      .keylen = 256 / 8, .mode = cm_cfb1,   },
      { .name = "AES-128-CFB8,",      .algo = "aes",      .keylen = 128 / 8, .mode = cm_cfb8,   },
      { .name = "AES-192-CFB8,",      .algo = "aes",      .keylen = 192 / 8, .mode = cm_cfb8,   },
      { .name = "AES-256-CFB8,",      .algo = "aes",      .keylen = 256 / 8, .mode = cm_cfb8,   },
      { .name = "AES-128-CTR,",       .algo = "aes",      .keylen = 128 / 8, .mode = cm_ctr,    },
      { .name = "AES-192-CTR,",       .algo = "aes",      .keylen = 192 / 8, .mode = cm_ctr,    },
      { .name = "AES-256-CTR,",       .algo = "aes",      .keylen = 256 / 8, .mode = cm_ctr,    },
      { .name = "AES-128-OFB,",       .algo = "aes",      .keylen = 128 / 8, .mode = cm_ofb,    },
      { .name = "AES-192-OFB,",       .algo = "aes",      .keylen = 192 / 8, .mode = cm_ofb,    },
      { .name = "AES-256-OFB,",       .algo = "aes",      .keylen = 256 / 8, .mode = cm_ofb,    },
      { .name = "BF-CBC,",            .algo = "blowfish", .keylen = 128 / 8, .mode = cm_cbc,    },
      { .name = "BF-CFB,",            .algo = "blowfish", .keylen = 128 / 8, .mode = cm_cfb,    },
      { .name = "BF-OFB,",            .algo = "blowfish", .keylen = 128 / 8, .mode = cm_ofb,    },
      { .name = "CAMELLIA-128-CBC,",  .algo = "camellia", .keylen = 128 / 8, .mode = cm_cbc,    },
      { .name = "CAMELLIA-192-CBC,",  .algo = "camellia", .keylen = 192 / 8, .mode = cm_cbc,    },
      { .name = "CAMELLIA-256-CBC,",  .algo = "camellia", .keylen = 256 / 8, .mode = cm_cbc,    },
      { .name = "CAMELLIA-128-CFB,",  .algo = "camellia", .keylen = 128 / 8, .mode = cm_cfb,    },
      { .name = "CAMELLIA-192-CFB,",  .algo = "camellia", .keylen = 192 / 8, .mode = cm_cfb,    },
      { .name = "CAMELLIA-256-CFB,",  .algo = "camellia", .keylen = 256 / 8, .mode = cm_cfb,    },
      { .name = "CAMELLIA-128-CFB1,", .algo = "camellia", .keylen = 128 / 8, .mode = cm_cfb1,   },
      { .name = "CAMELLIA-192-CFB1,", .algo = "camellia", .keylen = 192 / 8, .mode = cm_cfb1,   },
      { .name = "CAMELLIA-256-CFB1,", .algo = "camellia", .keylen = 256 / 8, .mode = cm_cfb1,   },
      { .name = "CAMELLIA-128-CFB8,", .algo = "camellia", .keylen = 128 / 8, .mode = cm_cfb8,   },
      { .name = "CAMELLIA-192-CFB8,", .algo = "camellia", .keylen = 192 / 8, .mode = cm_cfb8,   },
      { .name = "CAMELLIA-256-CFB8,", .algo = "camellia", .keylen = 256 / 8, .mode = cm_cfb8,   },
      { .name = "CAMELLIA-128-CTR,",  .algo = "camellia", .keylen = 128 / 8, .mode = cm_ctr,    },
      { .name = "CAMELLIA-192-CTR,",  .algo = "camellia", .keylen = 192 / 8, .mode = cm_ctr,    },
      { .name = "CAMELLIA-256-CTR,",  .algo = "camellia", .keylen = 256 / 8, .mode = cm_ctr,    },
      { .name = "CAMELLIA-128-OFB,",  .algo = "camellia", .keylen = 128 / 8, .mode = cm_ofb,    },
      { .name = "CAMELLIA-192-OFB,",  .algo = "camellia", .keylen = 192 / 8, .mode = cm_ofb,    },
      { .name = "CAMELLIA-256-OFB,",  .algo = "camellia", .keylen = 256 / 8, .mode = cm_ofb,    },
      { .name = "CAST5-CBC,",         .algo = "cast5",    .keylen = 128 / 8, .mode = cm_cbc,    },
      { .name = "CAST5-CFB,",         .algo = "cast5",    .keylen = 128 / 8, .mode = cm_cfb,    },
      { .name = "CAST5-OFB,",         .algo = "cast5",    .keylen = 128 / 8, .mode = cm_ofb,    },
      { .name = "ChaCha20,",          .algo = "chacha20", .keylen = 256 / 8, .mode = cm_stream, },
      { .name = "DES-EDE-CBC,",       .algo = "3des",     .keylen = 128 / 8, .mode = cm_cbc,    },
      { .name = "DES-EDE-CFB,",       .algo = "3des",     .keylen = 128 / 8, .mode = cm_cfb,    },
      { .name = "DES-EDE-OFB,",       .algo = "3des",     .keylen = 128 / 8, .mode = cm_ofb,    },
      { .name = "DES-EDE3-CBC,",      .algo = "3des",     .keylen = 192 / 8, .mode = cm_cbc,    },
      { .name = "DES-EDE3-CFB,",      .algo = "3des",     .keylen = 192 / 8, .mode = cm_cfb,    },
      { .name = "DES-EDE3-CFB1,",     .algo = "3des",     .keylen = 192 / 8, .mode = cm_cfb1,   },
      { .name = "DES-EDE3-CFB8,",     .algo = "3des",     .keylen = 192 / 8, .mode = cm_cfb8,   },
      { .name = "DES-EDE3-OFB,",      .algo = "3des",     .keylen = 192 / 8, .mode = cm_ofb,    },
      { .name = "DES-CBC,",           .algo = "des",      .keylen =  64 / 8, .mode = cm_cbc,    },
      { .name = "DES-CFB,",           .algo = "des",      .keylen =  64 / 8, .mode = cm_cfb,    },
      { .name = "DES-CFB1,",          .algo = "des",      .keylen =  64 / 8, .mode = cm_cfb1,   },
      { .name = "DES-CFB8,",          .algo = "des",      .keylen =  64 / 8, .mode = cm_cfb8,   },
      { .name = "DES-OFB,",           .algo = "des",      .keylen =  64 / 8, .mode = cm_ofb,    },
      { .name = "DESX-CBC,",          .algo = "desx",     .keylen = 192 / 8, .mode = cm_cbc,    },
      { .name = "IDEA-CBC,",          .algo = "idea",     .keylen = 128 / 8, .mode = cm_cbc,    },
      { .name = "IDEA-CFB,",          .algo = "idea",     .keylen = 128 / 8, .mode = cm_cfb,    },
      { .name = "IDEA-OFB,",          .algo = "idea",     .keylen = 128 / 8, .mode = cm_ofb,    },
      { .name = "RC5-CBC,",           .algo = "rc5",      .keylen = 128 / 8, .mode = cm_cbc,    },
      { .name = "RC5-CFB,",           .algo = "rc5",      .keylen = 128 / 8, .mode = cm_cfb,    },
      { .name = "RC5-OFB,",           .algo = "rc5",      .keylen = 128 / 8, .mode = cm_ofb,    },
      { .name = "RC2-40-CBC,",        .algo = "rc2",      .keylen =  40 / 8, .mode = cm_cbc,    },
      { .name = "RC2-64-CBC,",        .algo = "rc2",      .keylen =  64 / 8, .mode = cm_cbc,    },
      { .name = "RC2-CBC,",           .algo = "rc2",      .keylen = 128 / 8, .mode = cm_cbc,    },
      { .name = "RC2-CFB,",           .algo = "rc2",      .keylen = 128 / 8, .mode = cm_cfb,    },
      { .name = "RC2-OFB,",           .algo = "rc2",      .keylen = 128 / 8, .mode = cm_ofb,    },
      { .name = "SEED-CBC,",          .algo = "seed",     .keylen = 128 / 8, .mode = cm_cbc,    },
      { .name = "SEED-CFB,",          .algo = "seed",     .keylen = 128 / 8, .mode = cm_cfb,    },
      { .name = "SEED-OFB,",          .algo = "seed",     .keylen = 128 / 8, .mode = cm_ofb,    },
   };
const unsigned long pem_dek_infos_num = LTC_ARRAY_SIZE(pem_dek_infos);

int pem_decrypt(unsigned char *data, unsigned long *datalen,
                unsigned char *key,  unsigned long keylen,
                unsigned char *iv,   unsigned long ivlen,
                unsigned char *tag,  unsigned long taglen,
                const struct blockcipher_info *info,
                enum padding_type padding)
{
   int err, cipher = -1;
   struct {
      union {
#ifdef LTC_CBC_MODE
         symmetric_CBC cbc;
#endif
#ifdef LTC_CFB_MODE
         symmetric_CFB cfb;
#endif
#ifdef LTC_CTR_MODE
         symmetric_CTR ctr;
#endif
#ifdef LTC_OFB_MODE
         symmetric_OFB ofb;
#endif
      } ctx;
   } s;
   enum cipher_mode mode = info->mode & cm_modes;

   if (mode != cm_stream) {
      cipher = find_cipher(info->algo);
      if (cipher == -1) {
         return CRYPT_INVALID_CIPHER;
      }
   }

   switch (info->mode) {
      case cm_cbc:
#ifdef LTC_CBC_MODE
         LTC_ARGCHK(ivlen == (unsigned long)cipher_descriptor[cipher].block_length);

         if ((err = cbc_start(cipher, iv, key, keylen, 0, &s.ctx.cbc)) != CRYPT_OK) {
            goto error_out;
         }
         if ((err = cbc_decrypt(data, data, *datalen, &s.ctx.cbc)) != CRYPT_OK) {
            goto error_out;
         }
         if ((err = cbc_done(&s.ctx.cbc)) != CRYPT_OK) {
            goto error_out;
         }

         if ((err = padding_depad(data, datalen, padding | s.ctx.cbc.ecb.blocklen)) != CRYPT_OK) {
            goto error_out;
         }
#else
         return CRYPT_INVALID_CIPHER;
#endif
         break;
      case cm_cfb:
      case cm_cfb1:
      case cm_cfb8:
#ifdef LTC_CFB_MODE
         if (info->mode == cm_cfb) {
            if ((err = cfb_start(cipher, iv, key, keylen, 0, &s.ctx.cfb)) != CRYPT_OK) {
               goto error_out;
            }
         } else {
            if ((err = cfb_start_ex(cipher, iv, key, keylen, 0, info->mode == cm_cfb1 ? 1 : 8, &s.ctx.cfb)) != CRYPT_OK) {
               goto error_out;
            }
         }
         if ((err = cfb_decrypt(data, data, *datalen, &s.ctx.cfb)) != CRYPT_OK) {
            goto error_out;
         }
         if ((err = cfb_done(&s.ctx.cfb)) != CRYPT_OK) {
            goto error_out;
         }
#else
         return CRYPT_INVALID_CIPHER;
#endif
         break;
      case cm_ctr:
#ifdef LTC_CTR_MODE
         if ((err = ctr_start(cipher, iv, key, keylen, 0, CTR_COUNTER_BIG_ENDIAN, &s.ctx.ctr)) != CRYPT_OK) {
            goto error_out;
         }
         if ((err = ctr_decrypt(data, data, *datalen, &s.ctx.ctr)) != CRYPT_OK) {
            goto error_out;
         }
         if ((err = ctr_done(&s.ctx.ctr)) != CRYPT_OK) {
            goto error_out;
         }
#else
         return CRYPT_INVALID_CIPHER;
#endif
         break;
      case cm_ofb:
#ifdef LTC_OFB_MODE
         if ((err = ofb_start(cipher, iv, key, keylen, 0, &s.ctx.ofb)) != CRYPT_OK) {
            goto error_out;
         }
         if ((err = ofb_decrypt(data, data, *datalen, &s.ctx.ofb)) != CRYPT_OK) {
            goto error_out;
         }
         if ((err = ofb_done(&s.ctx.ofb)) != CRYPT_OK) {
            goto error_out;
         }
#else
         return CRYPT_INVALID_CIPHER;
#endif
         break;
      case cm_gcm:
#ifdef LTC_GCM_MODE
         if ((err = gcm_memory(cipher,
                               key, keylen,
                               iv, ivlen,
                               NULL, 0,
                               data, *datalen, data,
                               tag, &taglen,
                               GCM_DECRYPT)) != CRYPT_OK) {
            goto error_out;
         }
#else
         LTC_UNUSED_PARAM(tag);
         LTC_UNUSED_PARAM(taglen);
         return CRYPT_INVALID_CIPHER;
#endif
         break;
      case cm_stream:
#ifdef LTC_CHACHA
         LTC_ARGCHK(ivlen == 16);

         if ((err = chacha_memory(key, keylen, 20,
                                  iv, ivlen, 0,
                                  data, *datalen, data)) != CRYPT_OK) {
            goto error_out;
         }
#else
         return CRYPT_INVALID_CIPHER;
#endif
         break;
      case cm_stream_openssh:
#ifdef LTC_CHACHA20POLY1305_MODE
         if ((err = chacha20poly1305_memory(key, 32,
                                            iv, ivlen,
                                            NULL, 0,
                                            data, *datalen, data,
                                            tag, &taglen,
                                            CHACHA20POLY1305_DECRYPT | CHACHA20POLY1305_OPENSSH_COMPAT)) != CRYPT_OK) {
            goto error_out;
         }
#else
         return CRYPT_INVALID_CIPHER;
#endif
         break;
      default:
         err = CRYPT_INVALID_ARG;
         break;
   }

error_out:
   return err;
}

#ifndef LTC_NO_FILE
int pem_decode_filehandle(FILE *f, ltc_pka_key *k, const password_ctx *pw_ctx)
{
   int err = pem_decode_pkcs_filehandle(f, k, pw_ctx);
   if (err == CRYPT_OK || err != CRYPT_UNKNOWN_PEM)
      return err;
#if defined(LTC_SSH)
   rewind(f);
   err = pem_decode_openssh_filehandle(f, k, pw_ctx);
#endif
   return err;
}
#endif

int pem_decode(const void *buf, unsigned long len, ltc_pka_key *k, const password_ctx *pw_ctx)
{
   int err = pem_decode_pkcs(buf, len, k, pw_ctx);
   if (err == CRYPT_OK || err != CRYPT_UNKNOWN_PEM)
      return err;
#if defined(LTC_SSH)
   err = pem_decode_openssh(buf, len, k, pw_ctx);
#endif
   return err;
}

#endif /* LTC_PEM */
