michael@0: /* tlsprfalg.c - TLS Pseudo Random Function (PRF) implementation
michael@0:  *
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifdef FREEBL_NO_DEPEND
michael@0: #include "stubs.h"
michael@0: #endif
michael@0: 
michael@0: #include "blapi.h"
michael@0: #include "hasht.h"
michael@0: #include "alghmac.h"
michael@0: 
michael@0: 
michael@0: #define PHASH_STATE_MAX_LEN HASH_LENGTH_MAX
michael@0: 
michael@0: /* TLS P_hash function */
michael@0: SECStatus
michael@0: TLS_P_hash(HASH_HashType hashType, const SECItem *secret, const char *label, 
michael@0: 	SECItem *seed, SECItem *result, PRBool isFIPS)
michael@0: {
michael@0:     unsigned char state[PHASH_STATE_MAX_LEN];
michael@0:     unsigned char outbuf[PHASH_STATE_MAX_LEN];
michael@0:     unsigned int state_len = 0, label_len = 0, outbuf_len = 0, chunk_size;
michael@0:     unsigned int remaining;
michael@0:     unsigned char *res;
michael@0:     SECStatus status;
michael@0:     HMACContext *cx;
michael@0:     SECStatus rv = SECFailure;
michael@0:     const SECHashObject *hashObj = HASH_GetRawHashObject(hashType);
michael@0: 
michael@0:     PORT_Assert((secret != NULL) && (secret->data != NULL || !secret->len));
michael@0:     PORT_Assert((seed != NULL) && (seed->data != NULL));
michael@0:     PORT_Assert((result != NULL) && (result->data != NULL));
michael@0: 
michael@0:     remaining = result->len;
michael@0:     res = result->data;
michael@0: 
michael@0:     if (label != NULL)
michael@0: 	label_len = PORT_Strlen(label);
michael@0: 
michael@0:     cx = HMAC_Create(hashObj, secret->data, secret->len, isFIPS);
michael@0:     if (cx == NULL)
michael@0: 	goto loser;
michael@0: 
michael@0:     /* initialize the state = A(1) = HMAC_hash(secret, seed) */
michael@0:     HMAC_Begin(cx);
michael@0:     HMAC_Update(cx, (unsigned char *)label, label_len);
michael@0:     HMAC_Update(cx, seed->data, seed->len);
michael@0:     status = HMAC_Finish(cx, state, &state_len, sizeof(state));
michael@0:     if (status != SECSuccess)
michael@0: 	goto loser;
michael@0: 
michael@0:     /* generate a block at a time until we're done */
michael@0:     while (remaining > 0) {
michael@0: 
michael@0: 	HMAC_Begin(cx);
michael@0: 	HMAC_Update(cx, state, state_len);
michael@0: 	if (label_len)
michael@0: 	    HMAC_Update(cx, (unsigned char *)label, label_len);
michael@0: 	HMAC_Update(cx, seed->data, seed->len);
michael@0: 	status = HMAC_Finish(cx, outbuf, &outbuf_len, sizeof(outbuf));
michael@0: 	if (status != SECSuccess)
michael@0: 	    goto loser;
michael@0: 
michael@0:         /* Update the state = A(i) = HMAC_hash(secret, A(i-1)) */
michael@0: 	HMAC_Begin(cx); 
michael@0: 	HMAC_Update(cx, state, state_len); 
michael@0: 	status = HMAC_Finish(cx, state, &state_len, sizeof(state));
michael@0: 	if (status != SECSuccess)
michael@0: 	    goto loser;
michael@0: 
michael@0: 	chunk_size = PR_MIN(outbuf_len, remaining);
michael@0: 	PORT_Memcpy(res, &outbuf, chunk_size);
michael@0: 	res += chunk_size;
michael@0: 	remaining -= chunk_size;
michael@0:     }
michael@0: 
michael@0:     rv = SECSuccess;
michael@0: 
michael@0: loser:
michael@0:     /* clear out state so it's not left on the stack */
michael@0:     if (cx) 
michael@0:     	HMAC_Destroy(cx, PR_TRUE);
michael@0:     PORT_Memset(state, 0, sizeof(state));
michael@0:     PORT_Memset(outbuf, 0, sizeof(outbuf));
michael@0:     return rv;
michael@0: }
michael@0: 
michael@0: SECStatus
michael@0: TLS_PRF(const SECItem *secret, const char *label, SECItem *seed, 
michael@0:          SECItem *result, PRBool isFIPS)
michael@0: {
michael@0:     SECStatus rv = SECFailure, status;
michael@0:     unsigned int i;
michael@0:     SECItem tmp = { siBuffer, NULL, 0};
michael@0:     SECItem S1;
michael@0:     SECItem S2;
michael@0: 
michael@0:     PORT_Assert((secret != NULL) && (secret->data != NULL || !secret->len));
michael@0:     PORT_Assert((seed != NULL) && (seed->data != NULL));
michael@0:     PORT_Assert((result != NULL) && (result->data != NULL));
michael@0: 
michael@0:     S1.type = siBuffer;
michael@0:     S1.len  = (secret->len / 2) + (secret->len & 1);
michael@0:     S1.data = secret->data;
michael@0: 
michael@0:     S2.type = siBuffer;
michael@0:     S2.len  = S1.len;
michael@0:     S2.data = secret->data + (secret->len - S2.len);
michael@0: 
michael@0:     tmp.data = (unsigned char*)PORT_Alloc(result->len);
michael@0:     if (tmp.data == NULL)
michael@0: 	goto loser;
michael@0:     tmp.len = result->len;
michael@0: 
michael@0:     status = TLS_P_hash(HASH_AlgMD5, &S1, label, seed, result, isFIPS);
michael@0:     if (status != SECSuccess)
michael@0: 	goto loser;
michael@0: 
michael@0:     status = TLS_P_hash(HASH_AlgSHA1, &S2, label, seed, &tmp, isFIPS);
michael@0:     if (status != SECSuccess)
michael@0: 	goto loser;
michael@0: 
michael@0:     for (i = 0; i < result->len; i++)
michael@0: 	result->data[i] ^= tmp.data[i];
michael@0: 
michael@0:     rv = SECSuccess;
michael@0: 
michael@0: loser:
michael@0:     if (tmp.data != NULL)
michael@0: 	PORT_ZFree(tmp.data, tmp.len);
michael@0:     return rv;
michael@0: }
michael@0: