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/*
* Copyright (C) 2012 Martin Storsjo
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <string.h>
#include "hmac.h"
#include "md5.h"
#include "sha.h"
#include "mem.h"
#define MAX_HASHLEN 20
#define MAX_BLOCKLEN 64
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;
};
static void sha1_init(void *ctx)
{
av_sha_init(ctx, 160);
}
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 = av_md5_init;
c->update = av_md5_update;
c->final = av_md5_final;
c->hash = av_md5_alloc();
break;
case AV_HMAC_SHA1:
c->blocklen = 64;
c->hashlen = 20;
c->init = sha1_init;
c->update = av_sha_update;
c->final = av_sha_final;
c->hash = av_sha_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);
}
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