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/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
* All rights reserved.
*
* This package is an SSL implementation written
* by Eric Young (eay@cryptsoft.com).
* The implementation was written so as to conform with Netscapes SSL.
*
* This library is free for commercial and non-commercial use as long as
* the following conditions are aheared to. The following conditions
* apply to all code found in this distribution, be it the RC4, RSA,
* lhash, DES, etc., code; not just the SSL code. The SSL documentation
* included with this distribution is covered by the same copyright terms
* except that the holder is Tim Hudson (tjh@cryptsoft.com).
*
* Copyright remains Eric Young's, and as such any Copyright notices in
* the code are not to be removed.
* If this package is used in a product, Eric Young should be given attribution
* as the author of the parts of the library used.
* This can be in the form of a textual message at program startup or
* in documentation (online or textual) provided with the package.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* "This product includes cryptographic software written by
* Eric Young (eay@cryptsoft.com)"
* The word 'cryptographic' can be left out if the rouines from the library
* being used are not cryptographic related :-).
* 4. If you include any Windows specific code (or a derivative thereof) from
* the apps directory (application code) you must include an acknowledgement:
* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
*
* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* The licence and distribution terms for any publically available version or
* derivative of this code cannot be changed. i.e. this code cannot simply be
* copied and put under another distribution licence
* [including the GNU Public Licence.] */
#include <openssl/hmac.h>
#include <assert.h>
#include <string.h>
#include <openssl/mem.h>
uint8_t *HMAC(const EVP_MD *evp_md, const void *key, size_t key_len,
const uint8_t *data, size_t data_len, uint8_t *out,
unsigned int *out_len) {
HMAC_CTX ctx;
static uint8_t static_out_buffer[EVP_MAX_MD_SIZE];
/* OpenSSL has traditionally supported using a static buffer if |out| is
* NULL. We maintain that but don't document it. This behaviour should be
* considered to be deprecated. */
if (out == NULL) {
out = static_out_buffer;
}
HMAC_CTX_init(&ctx);
if (!HMAC_Init_ex(&ctx, key, key_len, evp_md, NULL) ||
!HMAC_Update(&ctx, data, data_len) ||
!HMAC_Final(&ctx, out, out_len)) {
out = NULL;
}
HMAC_CTX_cleanup(&ctx);
return out;
}
void HMAC_CTX_init(HMAC_CTX *ctx) {
ctx->md = NULL;
EVP_MD_CTX_init(&ctx->i_ctx);
EVP_MD_CTX_init(&ctx->o_ctx);
EVP_MD_CTX_init(&ctx->md_ctx);
}
void HMAC_CTX_cleanup(HMAC_CTX *ctx) {
EVP_MD_CTX_cleanup(&ctx->i_ctx);
EVP_MD_CTX_cleanup(&ctx->o_ctx);
EVP_MD_CTX_cleanup(&ctx->md_ctx);
OPENSSL_cleanse(ctx, sizeof(ctx));
}
int HMAC_Init_ex(HMAC_CTX *ctx, const void *key, size_t key_len,
const EVP_MD *md, ENGINE *impl) {
if (md == NULL) {
md = ctx->md;
}
/* If either |key| is non-NULL or |md| has changed, initialize with a new key
* rather than rewinding the previous one.
*
* TODO(davidben,eroman): Passing the previous |md| with a NULL |key| is
* ambiguous between using the empty key and reusing the previous key. There
* exist callers which intend the latter, but the former is an awkward edge
* case. Fix to API to avoid this. */
if (md != ctx->md || key != NULL) {
size_t i;
uint8_t pad[HMAC_MAX_MD_CBLOCK];
uint8_t key_block[HMAC_MAX_MD_CBLOCK];
unsigned key_block_len;
size_t block_size = EVP_MD_block_size(md);
assert(block_size <= sizeof(key_block));
if (block_size < key_len) {
/* Long keys are hashed. */
if (!EVP_DigestInit_ex(&ctx->md_ctx, md, impl) ||
!EVP_DigestUpdate(&ctx->md_ctx, key, key_len) ||
!EVP_DigestFinal_ex(&ctx->md_ctx, key_block, &key_block_len)) {
return 0;
}
} else {
assert(key_len >= 0 && key_len <= sizeof(key_block));
memcpy(key_block, key, key_len);
key_block_len = (unsigned)key_len;
}
/* Keys are then padded with zeros. */
if (key_block_len != HMAC_MAX_MD_CBLOCK) {
memset(&key_block[key_block_len], 0, sizeof(key_block) - key_block_len);
}
for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++) {
pad[i] = 0x36 ^ key_block[i];
}
if (!EVP_DigestInit_ex(&ctx->i_ctx, md, impl) ||
!EVP_DigestUpdate(&ctx->i_ctx, pad, EVP_MD_block_size(md))) {
return 0;
}
for (i = 0; i < HMAC_MAX_MD_CBLOCK; i++) {
pad[i] = 0x5c ^ key_block[i];
}
if (!EVP_DigestInit_ex(&ctx->o_ctx, md, impl) ||
!EVP_DigestUpdate(&ctx->o_ctx, pad, EVP_MD_block_size(md))) {
return 0;
}
ctx->md = md;
}
if (!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->i_ctx)) {
return 0;
}
return 1;
}
int HMAC_Update(HMAC_CTX *ctx, const uint8_t *data, size_t data_len) {
return EVP_DigestUpdate(&ctx->md_ctx, data, data_len);
}
int HMAC_Final(HMAC_CTX *ctx, uint8_t *out, unsigned int *out_len) {
unsigned int i;
uint8_t buf[EVP_MAX_MD_SIZE];
/* TODO(davidben): The only thing that can officially fail here is
* |EVP_MD_CTX_copy_ex|, but even that should be impossible in this case. */
if (!EVP_DigestFinal_ex(&ctx->md_ctx, buf, &i) ||
!EVP_MD_CTX_copy_ex(&ctx->md_ctx, &ctx->o_ctx) ||
!EVP_DigestUpdate(&ctx->md_ctx, buf, i) ||
!EVP_DigestFinal_ex(&ctx->md_ctx, out, out_len)) {
*out_len = 0;
return 0;
}
return 1;
}
size_t HMAC_size(const HMAC_CTX *ctx) {
return EVP_MD_size(ctx->md);
}
int HMAC_CTX_copy_ex(HMAC_CTX *dest, const HMAC_CTX *src) {
if (!EVP_MD_CTX_copy_ex(&dest->i_ctx, &src->i_ctx) ||
!EVP_MD_CTX_copy_ex(&dest->o_ctx, &src->o_ctx) ||
!EVP_MD_CTX_copy_ex(&dest->md_ctx, &src->md_ctx)) {
return 0;
}
dest->md = src->md;
return 1;
}
int HMAC_Init(HMAC_CTX *ctx, const void *key, int key_len, const EVP_MD *md) {
if (key && md) {
HMAC_CTX_init(ctx);
}
return HMAC_Init_ex(ctx, key, key_len, md, NULL);
}
int HMAC_CTX_copy(HMAC_CTX *dest, const HMAC_CTX *src) {
HMAC_CTX_init(dest);
return HMAC_CTX_copy_ex(dest, src);
}
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