yading@11: /*
yading@11:  * Copyright (C) 2012 Martin Storsjo
yading@11:  *
yading@11:  * This file is part of FFmpeg.
yading@11:  *
yading@11:  * FFmpeg is free software; you can redistribute it and/or
yading@11:  * modify it under the terms of the GNU Lesser General Public
yading@11:  * License as published by the Free Software Foundation; either
yading@11:  * version 2.1 of the License, or (at your option) any later version.
yading@11:  *
yading@11:  * FFmpeg is distributed in the hope that it will be useful,
yading@11:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@11:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@11:  * Lesser General Public License for more details.
yading@11:  *
yading@11:  * You should have received a copy of the GNU Lesser General Public
yading@11:  * License along with FFmpeg; if not, write to the Free Software
yading@11:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@11:  */
yading@11: 
yading@11: #include <string.h>
yading@11: 
yading@11: #include "hmac.h"
yading@11: #include "md5.h"
yading@11: #include "sha.h"
yading@11: #include "mem.h"
yading@11: 
yading@11: #define MAX_HASHLEN 20
yading@11: #define MAX_BLOCKLEN 64
yading@11: 
yading@11: struct AVHMAC {
yading@11:     void *hash;
yading@11:     int blocklen, hashlen;
yading@11:     void (*final)(void*, uint8_t*);
yading@11:     void (*update)(void*, const uint8_t*, int len);
yading@11:     void (*init)(void*);
yading@11:     uint8_t key[MAX_BLOCKLEN];
yading@11:     int keylen;
yading@11: };
yading@11: 
yading@11: static void sha1_init(void *ctx)
yading@11: {
yading@11:     av_sha_init(ctx, 160);
yading@11: }
yading@11: 
yading@11: AVHMAC *av_hmac_alloc(enum AVHMACType type)
yading@11: {
yading@11:     AVHMAC *c = av_mallocz(sizeof(*c));
yading@11:     if (!c)
yading@11:         return NULL;
yading@11:     switch (type) {
yading@11:     case AV_HMAC_MD5:
yading@11:         c->blocklen = 64;
yading@11:         c->hashlen  = 16;
yading@11:         c->init     = av_md5_init;
yading@11:         c->update   = av_md5_update;
yading@11:         c->final    = av_md5_final;
yading@11:         c->hash     = av_md5_alloc();
yading@11:         break;
yading@11:     case AV_HMAC_SHA1:
yading@11:         c->blocklen = 64;
yading@11:         c->hashlen  = 20;
yading@11:         c->init     = sha1_init;
yading@11:         c->update   = av_sha_update;
yading@11:         c->final    = av_sha_final;
yading@11:         c->hash     = av_sha_alloc();
yading@11:         break;
yading@11:     default:
yading@11:         av_free(c);
yading@11:         return NULL;
yading@11:     }
yading@11:     if (!c->hash) {
yading@11:         av_free(c);
yading@11:         return NULL;
yading@11:     }
yading@11:     return c;
yading@11: }
yading@11: 
yading@11: void av_hmac_free(AVHMAC *c)
yading@11: {
yading@11:     if (!c)
yading@11:         return;
yading@11:     av_free(c->hash);
yading@11:     av_free(c);
yading@11: }
yading@11: 
yading@11: void av_hmac_init(AVHMAC *c, const uint8_t *key, unsigned int keylen)
yading@11: {
yading@11:     int i;
yading@11:     uint8_t block[MAX_BLOCKLEN];
yading@11:     if (keylen > c->blocklen) {
yading@11:         c->init(c->hash);
yading@11:         c->update(c->hash, key, keylen);
yading@11:         c->final(c->hash, c->key);
yading@11:         c->keylen = c->hashlen;
yading@11:     } else {
yading@11:         memcpy(c->key, key, keylen);
yading@11:         c->keylen = keylen;
yading@11:     }
yading@11:     c->init(c->hash);
yading@11:     for (i = 0; i < c->keylen; i++)
yading@11:         block[i] = c->key[i] ^ 0x36;
yading@11:     for (i = c->keylen; i < c->blocklen; i++)
yading@11:         block[i] = 0x36;
yading@11:     c->update(c->hash, block, c->blocklen);
yading@11: }
yading@11: 
yading@11: void av_hmac_update(AVHMAC *c, const uint8_t *data, unsigned int len)
yading@11: {
yading@11:     c->update(c->hash, data, len);
yading@11: }
yading@11: 
yading@11: int av_hmac_final(AVHMAC *c, uint8_t *out, unsigned int outlen)
yading@11: {
yading@11:     uint8_t block[MAX_BLOCKLEN];
yading@11:     int i;
yading@11:     if (outlen < c->hashlen)
yading@11:         return AVERROR(EINVAL);
yading@11:     c->final(c->hash, out);
yading@11:     c->init(c->hash);
yading@11:     for (i = 0; i < c->keylen; i++)
yading@11:         block[i] = c->key[i] ^ 0x5C;
yading@11:     for (i = c->keylen; i < c->blocklen; i++)
yading@11:         block[i] = 0x5C;
yading@11:     c->update(c->hash, block, c->blocklen);
yading@11:     c->update(c->hash, out, c->hashlen);
yading@11:     c->final(c->hash, out);
yading@11:     return c->hashlen;
yading@11: }
yading@11: 
yading@11: int av_hmac_calc(AVHMAC *c, const uint8_t *data, unsigned int len,
yading@11:                  const uint8_t *key, unsigned int keylen,
yading@11:                  uint8_t *out, unsigned int outlen)
yading@11: {
yading@11:     av_hmac_init(c, key, keylen);
yading@11:     av_hmac_update(c, data, len);
yading@11:     return av_hmac_final(c, out, outlen);
yading@11: }
yading@11: 
yading@11: #ifdef TEST
yading@11: #include <stdio.h>
yading@11: 
yading@11: static void test(AVHMAC *hmac, const uint8_t *key, int keylen,
yading@11:                  const uint8_t *data, int datalen)
yading@11: {
yading@11:     uint8_t buf[MAX_HASHLEN];
yading@11:     int out, i;
yading@11:     // Some of the test vectors are strings, where sizeof() includes the
yading@11:     // trailing null byte - remove that.
yading@11:     if (!key[keylen - 1])
yading@11:         keylen--;
yading@11:     if (!data[datalen - 1])
yading@11:         datalen--;
yading@11:     out = av_hmac_calc(hmac, data, datalen, key, keylen, buf, sizeof(buf));
yading@11:     for (i = 0; i < out; i++)
yading@11:         printf("%02x", buf[i]);
yading@11:     printf("\n");
yading@11: }
yading@11: 
yading@11: int main(void)
yading@11: {
yading@11:     uint8_t key1[16], key3[16], data3[50], key4[63], key5[64], key6[65];
yading@11:     const uint8_t key2[]  = "Jefe";
yading@11:     const uint8_t data1[] = "Hi There";
yading@11:     const uint8_t data2[] = "what do ya want for nothing?";
yading@11:     AVHMAC *hmac = av_hmac_alloc(AV_HMAC_MD5);
yading@11:     if (!hmac)
yading@11:         return 1;
yading@11:     memset(key1, 0x0b, sizeof(key1));
yading@11:     memset(key3, 0xaa, sizeof(key3));
yading@11:     memset(key4, 0x44, sizeof(key4));
yading@11:     memset(key5, 0x55, sizeof(key5));
yading@11:     memset(key6, 0x66, sizeof(key6));
yading@11:     memset(data3, 0xdd, sizeof(data3));
yading@11:     // RFC 2104 test vectors
yading@11:     test(hmac, key1, sizeof(key1), data1, sizeof(data1));
yading@11:     test(hmac, key2, sizeof(key2), data2, sizeof(data2));
yading@11:     test(hmac, key3, sizeof(key3), data3, sizeof(data3));
yading@11:     // Additional tests, to test cases where the key is too long
yading@11:     test(hmac, key4, sizeof(key4), data1, sizeof(data1));
yading@11:     test(hmac, key5, sizeof(key5), data2, sizeof(data2));
yading@11:     test(hmac, key6, sizeof(key6), data3, sizeof(data3));
yading@11:     av_hmac_free(hmac);
yading@11:     return 0;
yading@11: }
yading@11: #endif /* TEST */