libavutil/hmac.c

   1 /*
   2  * Copyright (C) 2012 Martin Storsjo
   3  *
   4  * This file is part of Libav.
   5  *
   6  * Libav is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * Libav is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with Libav; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #include <string.h>
  22
  23 #include "attributes.h"
  24 #include "hmac.h"
  25 #include "md5.h"
  26 #include "sha.h"
  27 #include "mem.h"
  28
  29 #define MAX_HASHLEN 32
  30 #define MAX_BLOCKLEN 64
  31
  32 struct AVHMAC {
  33     void *hash;
  34     int blocklen, hashlen;
  35     void (*final)(void*, uint8_t*);
  36     void (*update)(void*, const uint8_t*, int len);
  37     void (*init)(void*);
  38     uint8_t key[MAX_BLOCKLEN];
  39     int keylen;
  40 };
  41
  42 #define DEFINE_SHA(bits)                           \
  43 static av_cold void sha ## bits ##_init(void *ctx) \
  44 {                                                  \
  45     av_sha_init(ctx, bits);                        \
  46 }
  47
  48 DEFINE_SHA(160)
  49 DEFINE_SHA(224)
  50 DEFINE_SHA(256)
  51
  52 AVHMAC *av_hmac_alloc(enum AVHMACType type)
  53 {
  54     AVHMAC *c = av_mallocz(sizeof(*c));
  55     if (!c)
  56         return NULL;
  57     switch (type) {
  58     case AV_HMAC_MD5:
  59         c->blocklen = 64;
  60         c->hashlen  = 16;
  61         c->init     = av_md5_init;
  62         c->update   = av_md5_update;
  63         c->final    = av_md5_final;
  64         c->hash     = av_md5_alloc();
  65         break;
  66     case AV_HMAC_SHA1:
  67         c->blocklen = 64;
  68         c->hashlen  = 20;
  69         c->init     = sha160_init;
  70         c->update   = av_sha_update;
  71         c->final    = av_sha_final;
  72         c->hash     = av_sha_alloc();
  73         break;
  74     case AV_HMAC_SHA224:
  75         c->blocklen = 64;
  76         c->hashlen  = 28;
  77         c->init     = sha224_init;
  78         c->update   = av_sha_update;
  79         c->final    = av_sha_final;
  80         c->hash     = av_sha_alloc();
  81         break;
  82     case AV_HMAC_SHA256:
  83         c->blocklen = 64;
  84         c->hashlen  = 32;
  85         c->init     = sha256_init;
  86         c->update   = av_sha_update;
  87         c->final    = av_sha_final;
  88         c->hash     = av_sha_alloc();
  89         break;
  90     default:
  91         av_free(c);
  92         return NULL;
  93     }
  94     if (!c->hash) {
  95         av_free(c);
  96         return NULL;
  97     }
  98     return c;
  99 }
 100
 101 void av_hmac_free(AVHMAC *c)
 102 {
 103     if (!c)
 104         return;
 105     av_free(c->hash);
 106     av_free(c);
 107 }
 108
 109 void av_hmac_init(AVHMAC *c, const uint8_t *key, unsigned int keylen)
 110 {
 111     int i;
 112     uint8_t block[MAX_BLOCKLEN];
 113     if (keylen > c->blocklen) {
 114         c->init(c->hash);
 115         c->update(c->hash, key, keylen);
 116         c->final(c->hash, c->key);
 117         c->keylen = c->hashlen;
 118     } else {
 119         memcpy(c->key, key, keylen);
 120         c->keylen = keylen;
 121     }
 122     c->init(c->hash);
 123     for (i = 0; i < c->keylen; i++)
 124         block[i] = c->key[i] ^ 0x36;
 125     for (i = c->keylen; i < c->blocklen; i++)
 126         block[i] = 0x36;
 127     c->update(c->hash, block, c->blocklen);
 128 }
 129
 130 void av_hmac_update(AVHMAC *c, const uint8_t *data, unsigned int len)
 131 {
 132     c->update(c->hash, data, len);
 133 }
 134
 135 int av_hmac_final(AVHMAC *c, uint8_t *out, unsigned int outlen)
 136 {
 137     uint8_t block[MAX_BLOCKLEN];
 138     int i;
 139     if (outlen < c->hashlen)
 140         return AVERROR(EINVAL);
 141     c->final(c->hash, out);
 142     c->init(c->hash);
 143     for (i = 0; i < c->keylen; i++)
 144         block[i] = c->key[i] ^ 0x5C;
 145     for (i = c->keylen; i < c->blocklen; i++)
 146         block[i] = 0x5C;
 147     c->update(c->hash, block, c->blocklen);
 148     c->update(c->hash, out, c->hashlen);
 149     c->final(c->hash, out);
 150     return c->hashlen;
 151 }
 152
 153 int av_hmac_calc(AVHMAC *c, const uint8_t *data, unsigned int len,
 154                  const uint8_t *key, unsigned int keylen,
 155                  uint8_t *out, unsigned int outlen)
 156 {
 157     av_hmac_init(c, key, keylen);
 158     av_hmac_update(c, data, len);
 159     return av_hmac_final(c, out, outlen);
 160 }
 161
 162 #ifdef TEST
 163 #include <stdio.h>
 164
 165 static void test(AVHMAC *hmac, const uint8_t *key, int keylen,
 166                  const uint8_t *data, int datalen)
 167 {
 168     uint8_t buf[MAX_HASHLEN];
 169     int out, i;
 170     // Some of the test vectors are strings, where sizeof() includes the
 171     // trailing null byte - remove that.
 172     if (!key[keylen - 1])
 173         keylen--;
 174     if (!data[datalen - 1])
 175         datalen--;
 176     out = av_hmac_calc(hmac, data, datalen, key, keylen, buf, sizeof(buf));
 177     for (i = 0; i < out; i++)
 178         printf("%02x", buf[i]);
 179     printf("\n");
 180 }
 181
 182 int main(void)
 183 {
 184     uint8_t key1[16], key3[16], data3[50], key4[63], key5[64], key6[65];
 185     const uint8_t key2[]  = "Jefe";
 186     const uint8_t data1[] = "Hi There";
 187     const uint8_t data2[] = "what do ya want for nothing?";
 188     AVHMAC *hmac = av_hmac_alloc(AV_HMAC_MD5);
 189     if (!hmac)
 190         return 1;
 191     memset(key1, 0x0b, sizeof(key1));
 192     memset(key3, 0xaa, sizeof(key3));
 193     memset(key4, 0x44, sizeof(key4));
 194     memset(key5, 0x55, sizeof(key5));
 195     memset(key6, 0x66, sizeof(key6));
 196     memset(data3, 0xdd, sizeof(data3));
 197     // RFC 2104 test vectors
 198     test(hmac, key1, sizeof(key1), data1, sizeof(data1));
 199     test(hmac, key2, sizeof(key2), data2, sizeof(data2));
 200     test(hmac, key3, sizeof(key3), data3, sizeof(data3));
 201     // Additional tests, to test cases where the key is too long
 202     test(hmac, key4, sizeof(key4), data1, sizeof(data1));
 203     test(hmac, key5, sizeof(key5), data2, sizeof(data2));
 204     test(hmac, key6, sizeof(key6), data3, sizeof(data3));
 205     av_hmac_free(hmac);
 206     return 0;
 207 }
 208 #endif /* TEST */