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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifdef FREEBL_NO_DEPEND
#include "stubs.h"
#endif
#include "secport.h"
#include "hasht.h"
#include "blapit.h"
#include "alghmac.h"
#include "secerr.h"
#define HMAC_PAD_SIZE HASH_BLOCK_LENGTH_MAX
struct HMACContextStr {
void *hash;
const SECHashObject *hashobj;
PRBool wasAllocated;
unsigned char ipad[HMAC_PAD_SIZE];
unsigned char opad[HMAC_PAD_SIZE];
};
void
HMAC_Destroy(HMACContext *cx, PRBool freeit)
{
if (cx == NULL)
return;
PORT_Assert(!freeit == !cx->wasAllocated);
if (cx->hash != NULL) {
cx->hashobj->destroy(cx->hash, PR_TRUE);
PORT_Memset(cx, 0, sizeof *cx);
}
if (freeit)
PORT_Free(cx);
}
static SECStatus
hmac_initKey(HMACContext *cx, const unsigned char *secret,
unsigned int secret_len, PRBool isFIPS)
{
unsigned int i;
unsigned char hashed_secret[HASH_LENGTH_MAX];
/* required by FIPS 198 Section 3 */
if (isFIPS && secret_len < cx->hashobj->length / 2) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
if (secret_len > cx->hashobj->blocklength) {
cx->hashobj->begin(cx->hash);
cx->hashobj->update(cx->hash, secret, secret_len);
PORT_Assert(cx->hashobj->length <= sizeof hashed_secret);
cx->hashobj->end(cx->hash, hashed_secret, &secret_len,
sizeof hashed_secret);
if (secret_len != cx->hashobj->length) {
PORT_SetError(SEC_ERROR_LIBRARY_FAILURE);
goto loser;
}
secret = (const unsigned char *)&hashed_secret[0];
}
PORT_Memset(cx->ipad, 0x36, cx->hashobj->blocklength);
PORT_Memset(cx->opad, 0x5c, cx->hashobj->blocklength);
/* fold secret into padding */
for (i = 0; i < secret_len; i++) {
cx->ipad[i] ^= secret[i];
cx->opad[i] ^= secret[i];
}
PORT_Memset(hashed_secret, 0, sizeof hashed_secret);
return SECSuccess;
loser:
PORT_Memset(hashed_secret, 0, sizeof hashed_secret);
return SECFailure;
}
SECStatus
HMAC_Init(HMACContext *cx, const SECHashObject *hash_obj,
const unsigned char *secret, unsigned int secret_len, PRBool isFIPS)
{
SECStatus rv;
if (cx == NULL) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
cx->wasAllocated = PR_FALSE;
cx->hashobj = hash_obj;
cx->hash = cx->hashobj->create();
if (cx->hash == NULL)
goto loser;
rv = hmac_initKey(cx, secret, secret_len, isFIPS);
if (rv != SECSuccess)
goto loser;
return rv;
loser:
if (cx->hash != NULL)
cx->hashobj->destroy(cx->hash, PR_TRUE);
return SECFailure;
}
HMACContext *
HMAC_Create(const SECHashObject *hash_obj, const unsigned char *secret,
unsigned int secret_len, PRBool isFIPS)
{
SECStatus rv;
HMACContext *cx = PORT_ZNew(HMACContext);
if (cx == NULL)
return NULL;
rv = HMAC_Init(cx, hash_obj, secret, secret_len, isFIPS);
cx->wasAllocated = PR_TRUE;
if (rv != SECSuccess) {
PORT_Free(cx); /* contains no secret info */
cx = NULL;
}
return cx;
}
/* this allows us to reuse an existing HMACContext with a new key and
* Hash function */
SECStatus
HMAC_ReInit(HMACContext *cx, const SECHashObject *hash_obj,
const unsigned char *secret, unsigned int secret_len, PRBool isFIPS)
{
PRBool wasAllocated;
SECStatus rv;
/* if we are using the same hash, keep the hash contexts and only
* init the key */
if ((cx->hashobj == hash_obj) && (cx->hash != NULL)) {
return hmac_initKey(cx, secret, secret_len, isFIPS);
}
/* otherwise we destroy the contents of the context and
* initalize it from scratch. We need to preseve the current state
* of wasAllocated to the final destroy works correctly */
wasAllocated = cx->wasAllocated;
cx->wasAllocated = PR_FALSE;
HMAC_Destroy(cx, PR_FALSE);
rv = HMAC_Init(cx, hash_obj, secret, secret_len, isFIPS);
if (rv != SECSuccess) {
return rv;
}
cx->wasAllocated = wasAllocated;
return SECSuccess;
}
void
HMAC_Begin(HMACContext *cx)
{
/* start inner hash */
cx->hashobj->begin(cx->hash);
cx->hashobj->update(cx->hash, cx->ipad, cx->hashobj->blocklength);
}
void
HMAC_Update(HMACContext *cx, const unsigned char *data, unsigned int data_len)
{
cx->hashobj->update(cx->hash, data, data_len);
}
SECStatus
HMAC_Finish(HMACContext *cx, unsigned char *result, unsigned int *result_len,
unsigned int max_result_len)
{
if (max_result_len < cx->hashobj->length) {
PORT_SetError(SEC_ERROR_INVALID_ARGS);
return SECFailure;
}
cx->hashobj->end(cx->hash, result, result_len, max_result_len);
if (*result_len != cx->hashobj->length)
return SECFailure;
cx->hashobj->begin(cx->hash);
cx->hashobj->update(cx->hash, cx->opad, cx->hashobj->blocklength);
cx->hashobj->update(cx->hash, result, *result_len);
cx->hashobj->end(cx->hash, result, result_len, max_result_len);
return SECSuccess;
}
HMACContext *
HMAC_Clone(HMACContext *cx)
{
HMACContext *newcx;
newcx = (HMACContext *)PORT_ZAlloc(sizeof(HMACContext));
if (newcx == NULL)
goto loser;
newcx->wasAllocated = PR_TRUE;
newcx->hashobj = cx->hashobj;
newcx->hash = cx->hashobj->clone(cx->hash);
if (newcx->hash == NULL)
goto loser;
PORT_Memcpy(newcx->ipad, cx->ipad, cx->hashobj->blocklength);
PORT_Memcpy(newcx->opad, cx->opad, cx->hashobj->blocklength);
return newcx;
loser:
HMAC_Destroy(newcx, PR_TRUE);
return NULL;
}
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