text: /*
   * Copyright (C) 2012 Martin Storsjo
   *
   * This file is part of FFmpeg.
   *
   * FFmpeg is free software; you can redistribute it and/or
   * modify it under the terms of the GNU Lesser General Public
   * License as published by the Free Software Foundation; either
   * version 2.1 of the License, or (at your option) any later version.
   *
   * FFmpeg is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   * Lesser General Public License for more details.
   *
   * You should have received a copy of the GNU Lesser General Public
   * License along with FFmpeg; if not, write to the Free Software
   * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
   */
  
  #include <string.h>
  
  #include "attributes.h"
  #include "hmac.h"
  #include "md5.h"
  #include "sha.h"
  #include "sha512.h"
  #include "mem.h"
  
  #define MAX_HASHLEN 64
  #define MAX_BLOCKLEN 128
  
  struct AVHMAC {
      void *hash;
      int blocklen, hashlen;
      void (*final)(void*, uint8_t*);
      void (*update)(void*, const uint8_t*, int len);
      void (*init)(void*);
      uint8_t key[MAX_BLOCKLEN];
      int keylen;
  };
  
  #define DEFINE_SHA(bits)                           \
  static av_cold void sha ## bits ##_init(void *ctx) \
  {                                                  \
      av_sha_init(ctx, bits);                        \
  }
  
  #define DEFINE_SHA512(bits)                        \
  static av_cold void sha ## bits ##_init(void *ctx) \
  {                                                  \
      av_sha512_init(ctx, bits);                     \
  }
  
  DEFINE_SHA(160)
  DEFINE_SHA(224)
  DEFINE_SHA(256)
  DEFINE_SHA512(384)
  DEFINE_SHA512(512)
  
  AVHMAC *av_hmac_alloc(enum AVHMACType type)
  {
      AVHMAC *c = av_mallocz(sizeof(*c));
      if (!c)
          return NULL;
      switch (type) {
      case AV_HMAC_MD5:
          c->blocklen = 64;
          c->hashlen  = 16;
          c->init     = (void*)av_md5_init;
          c->update   = (void*)av_md5_update;
          c->final    = (void*)av_md5_final;
          c->hash     = av_md5_alloc();
          break;
      case AV_HMAC_SHA1:
          c->blocklen = 64;
          c->hashlen  = 20;
          c->init     = sha160_init;
          c->update   = (void*)av_sha_update;
          c->final    = (void*)av_sha_final;
          c->hash     = av_sha_alloc();
          break;
      case AV_HMAC_SHA224:
          c->blocklen = 64;
          c->hashlen  = 28;
          c->init     = sha224_init;
          c->update   = (void*)av_sha_update;
          c->final    = (void*)av_sha_final;
          c->hash     = av_sha_alloc();
          break;
      case AV_HMAC_SHA256:
          c->blocklen = 64;
          c->hashlen  = 32;
          c->init     = sha256_init;
          c->update   = (void*)av_sha_update;
          c->final    = (void*)av_sha_final;
          c->hash     = av_sha_alloc();
          break;
      case AV_HMAC_SHA384:
          c->blocklen = 128;
          c->hashlen  = 48;
          c->init     = sha384_init;
          c->update   = (void*)av_sha512_update;
          c->final    = (void*)av_sha512_final;
          c->hash     = av_sha512_alloc();
          break;
      case AV_HMAC_SHA512:
          c->blocklen = 128;
          c->hashlen  = 64;
          c->init     = sha512_init;
          c->update   = (void*)av_sha512_update;
          c->final    = (void*)av_sha512_final;
          c->hash     = av_sha512_alloc();
          break;
      default:
          av_free(c);
          return NULL;
      }
      if (!c->hash) {
          av_free(c);
          return NULL;
      }
      return c;
  }
  
  void av_hmac_free(AVHMAC *c)
  {
      if (!c)
          return;
      av_free(c->hash);
      av_free(c);
  }
  
  void av_hmac_init(AVHMAC *c, const uint8_t *key, unsigned int keylen)
  {
      int i;
      uint8_t block[MAX_BLOCKLEN];
      if (keylen > c->blocklen) {
          c->init(c->hash);
          c->update(c->hash, key, keylen);
          c->final(c->hash, c->key);
          c->keylen = c->hashlen;
      } else {
          memcpy(c->key, key, keylen);
          c->keylen = keylen;
      }
      c->init(c->hash);
      for (i = 0; i < c->keylen; i++)
          block[i] = c->key[i] ^ 0x36;
      for (i = c->keylen; i < c->blocklen; i++)
          block[i] = 0x36;
      c->update(c->hash, block, c->blocklen);
  }
  
  void av_hmac_update(AVHMAC *c, const uint8_t *data, unsigned int len)
  {
      c->update(c->hash, data, len);
  }
  
  int av_hmac_final(AVHMAC *c, uint8_t *out, unsigned int outlen)
  {
      uint8_t block[MAX_BLOCKLEN];
      int i;
      if (outlen < c->hashlen)
          return AVERROR(EINVAL);
      c->final(c->hash, out);
      c->init(c->hash);
      for (i = 0; i < c->keylen; i++)
          block[i] = c->key[i] ^ 0x5C;
      for (i = c->keylen; i < c->blocklen; i++)
          block[i] = 0x5C;
      c->update(c->hash, block, c->blocklen);
      c->update(c->hash, out, c->hashlen);
      c->final(c->hash, out);
      return c->hashlen;
  }
  
  int av_hmac_calc(AVHMAC *c, const uint8_t *data, unsigned int len,
                   const uint8_t *key, unsigned int keylen,
                   uint8_t *out, unsigned int outlen)
  {
      av_hmac_init(c, key, keylen);
      av_hmac_update(c, data, len);
      return av_hmac_final(c, out, outlen);
  }
  
  #ifdef TEST
  #include <stdio.h>
  
  static void test(AVHMAC *hmac, const uint8_t *key, int keylen,
                   const uint8_t *data, int datalen)
  {
      uint8_t buf[MAX_HASHLEN];
      int out, i;
      // Some of the test vectors are strings, where sizeof() includes the
      // trailing null byte - remove that.
      if (!key[keylen - 1])
          keylen--;
      if (!data[datalen - 1])
          datalen--;
      out = av_hmac_calc(hmac, data, datalen, key, keylen, buf, sizeof(buf));
      for (i = 0; i < out; i++)
          printf("%02x", buf[i]);
      printf("\n");
  }
  
  int main(void)
  {
      uint8_t key1[20], key3[131], data3[50];
      enum AVHMACType i = AV_HMAC_SHA224;
      const uint8_t key2[]  = "Jefe";
      const uint8_t data1[] = "Hi There";
      const uint8_t data2[] = "what do ya want for nothing?";
      const uint8_t data4[] = "Test Using Larger Than Block-Size Key - Hash Key First";
      const uint8_t data5[] = "Test Using Larger Than Block-Size Key and Larger Than One Block-Size Data";
      const uint8_t data6[] = "This is a test using a larger than block-size key and a larger "
                              "than block-size data. The key needs to be hashed before being used"
                              " by the HMAC algorithm.";
      AVHMAC *hmac = av_hmac_alloc(AV_HMAC_MD5);
      if (!hmac)
          return 1;
      memset(key1, 0x0b, sizeof(key1));
      memset(key3, 0xaa, sizeof(key3));
      memset(data3, 0xdd, sizeof(data3));
      // RFC 2202 test vectors
      test(hmac, key1, 16, data1, sizeof(data1));
      test(hmac, key2, sizeof(key2), data2, sizeof(data2));
      test(hmac, key3, 16, data3, sizeof(data3));
      test(hmac, key3, 80, data4, sizeof(data4));
      test(hmac, key3, 80, data5, sizeof(data5));
      av_hmac_free(hmac);
  
      /* SHA-1 */
      hmac = av_hmac_alloc(AV_HMAC_SHA1);
      if (!hmac)
          return 1;
      // RFC 2202 test vectors
      test(hmac, key1, sizeof(key1), data1, sizeof(data1));
      test(hmac, key2, sizeof(key2), data2, sizeof(data2));
      test(hmac, key3, 20, data3, sizeof(data3));
      test(hmac, key3, 80, data4, sizeof(data4));
      test(hmac, key3, 80, data5, sizeof(data5));
      av_hmac_free(hmac);
  
      /* SHA-2 */
      while (i <= AV_HMAC_SHA512) {
          hmac = av_hmac_alloc(i);
          // RFC 4231 test vectors
          test(hmac, key1, sizeof(key1), data1, sizeof(data1));
          test(hmac, key2, sizeof(key2), data2, sizeof(data2));
          test(hmac, key3, 20, data3, sizeof(data3));
          test(hmac, key3, sizeof(key3), data4, sizeof(data4));
          test(hmac, key3, sizeof(key3), data6, sizeof(data6));
          av_hmac_free(hmac);
          i++;
      }
      return 0;
  }
  #endif /* TEST */
  