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 20
  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 static av_cold void sha1_init(void *ctx)
  43 {
  44     av_sha_init(ctx, 160);
  45 }
  46
  47 AVHMAC *av_hmac_alloc(enum AVHMACType type)
  48 {
  49     AVHMAC *c = av_mallocz(sizeof(*c));
  50     if (!c)
  51         return NULL;
  52     switch (type) {
  53     case AV_HMAC_MD5:
  54         c->blocklen = 64;
  55         c->hashlen  = 16;
  56         c->init     = av_md5_init;
  57         c->update   = av_md5_update;
  58         c->final    = av_md5_final;
  59         c->hash     = av_md5_alloc();
  60         break;
  61     case AV_HMAC_SHA1:
  62         c->blocklen = 64;
  63         c->hashlen  = 20;
  64         c->init     = sha1_init;
  65         c->update   = av_sha_update;
  66         c->final    = av_sha_final;
  67         c->hash     = av_sha_alloc();
  68         break;
  69     default:
  70         av_free(c);
  71         return NULL;
  72     }
  73     if (!c->hash) {
  74         av_free(c);
  75         return NULL;
  76     }
  77     return c;
  78 }
  79
  80 void av_hmac_free(AVHMAC *c)
  81 {
  82     if (!c)
  83         return;
  84     av_free(c->hash);
  85     av_free(c);
  86 }
  87
  88 void av_hmac_init(AVHMAC *c, const uint8_t *key, unsigned int keylen)
  89 {
  90     int i;
  91     uint8_t block[MAX_BLOCKLEN];
  92     if (keylen > c->blocklen) {
  93         c->init(c->hash);
  94         c->update(c->hash, key, keylen);
  95         c->final(c->hash, c->key);
  96         c->keylen = c->hashlen;
  97     } else {
  98         memcpy(c->key, key, keylen);
  99         c->keylen = keylen;
 100     }
 101     c->init(c->hash);
 102     for (i = 0; i < c->keylen; i++)
 103         block[i] = c->key[i] ^ 0x36;
 104     for (i = c->keylen; i < c->blocklen; i++)
 105         block[i] = 0x36;
 106     c->update(c->hash, block, c->blocklen);
 107 }
 108
 109 void av_hmac_update(AVHMAC *c, const uint8_t *data, unsigned int len)
 110 {
 111     c->update(c->hash, data, len);
 112 }
 113
 114 int av_hmac_final(AVHMAC *c, uint8_t *out, unsigned int outlen)
 115 {
 116     uint8_t block[MAX_BLOCKLEN];
 117     int i;
 118     if (outlen < c->hashlen)
 119         return AVERROR(EINVAL);
 120     c->final(c->hash, out);
 121     c->init(c->hash);
 122     for (i = 0; i < c->keylen; i++)
 123         block[i] = c->key[i] ^ 0x5C;
 124     for (i = c->keylen; i < c->blocklen; i++)
 125         block[i] = 0x5C;
 126     c->update(c->hash, block, c->blocklen);
 127     c->update(c->hash, out, c->hashlen);
 128     c->final(c->hash, out);
 129     return c->hashlen;
 130 }
 131
 132 int av_hmac_calc(AVHMAC *c, const uint8_t *data, unsigned int len,
 133                  const uint8_t *key, unsigned int keylen,
 134                  uint8_t *out, unsigned int outlen)
 135 {
 136     av_hmac_init(c, key, keylen);
 137     av_hmac_update(c, data, len);
 138     return av_hmac_final(c, out, outlen);
 139 }
 140
 141 #ifdef TEST
 142 #include <stdio.h>
 143
 144 static void test(AVHMAC *hmac, const uint8_t *key, int keylen,
 145                  const uint8_t *data, int datalen)
 146 {
 147     uint8_t buf[MAX_HASHLEN];
 148     int out, i;
 149     // Some of the test vectors are strings, where sizeof() includes the
 150     // trailing null byte - remove that.
 151     if (!key[keylen - 1])
 152         keylen--;
 153     if (!data[datalen - 1])
 154         datalen--;
 155     out = av_hmac_calc(hmac, data, datalen, key, keylen, buf, sizeof(buf));
 156     for (i = 0; i < out; i++)
 157         printf("%02x", buf[i]);
 158     printf("\n");
 159 }
 160
 161 int main(void)
 162 {
 163     uint8_t key1[16], key3[16], data3[50], key4[63], key5[64], key6[65];
 164     const uint8_t key2[]  = "Jefe";
 165     const uint8_t data1[] = "Hi There";
 166     const uint8_t data2[] = "what do ya want for nothing?";
 167     AVHMAC *hmac = av_hmac_alloc(AV_HMAC_MD5);
 168     if (!hmac)
 169         return 1;
 170     memset(key1, 0x0b, sizeof(key1));
 171     memset(key3, 0xaa, sizeof(key3));
 172     memset(key4, 0x44, sizeof(key4));
 173     memset(key5, 0x55, sizeof(key5));
 174     memset(key6, 0x66, sizeof(key6));
 175     memset(data3, 0xdd, sizeof(data3));
 176     // RFC 2104 test vectors
 177     test(hmac, key1, sizeof(key1), data1, sizeof(data1));
 178     test(hmac, key2, sizeof(key2), data2, sizeof(data2));
 179     test(hmac, key3, sizeof(key3), data3, sizeof(data3));
 180     // Additional tests, to test cases where the key is too long
 181     test(hmac, key4, sizeof(key4), data1, sizeof(data1));
 182     test(hmac, key5, sizeof(key5), data2, sizeof(data2));
 183     test(hmac, key6, sizeof(key6), data3, sizeof(data3));
 184     av_hmac_free(hmac);
 185     return 0;
 186 }
 187 #endif /* TEST */