mirror of https://github.com/wolfSSL/wolfssl
tls: refactoring p_hash to reduce stack usage:
--- variable previous moved to the heap (up to 48 bytes saved) --- variable current moved to the heap (up to 48 bytes saved) --- variable hmac moved to the heap (sizeof(Hmac) bytes saved)
This commit is contained in:
Moisés Guimarães
parent
9429f07a8a
commit
e3db86753c
174
src/tls.c
174
src/tls.c
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@ -46,109 +46,131 @@
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#ifdef CYASSL_SHA384
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#define PHASH_MAX_DIGEST_SIZE SHA384_DIGEST_SIZE
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#define P_HASH_MAX_SIZE SHA384_DIGEST_SIZE
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#else
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#define PHASH_MAX_DIGEST_SIZE SHA256_DIGEST_SIZE
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#define P_HASH_MAX_SIZE SHA256_DIGEST_SIZE
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#endif
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/* compute p_hash for MD5, SHA-1, SHA-256, or SHA-384 for TLSv1 PRF */
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static int p_hash(byte* result, word32 resLen, const byte* secret,
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word32 secLen, const byte* seed, word32 seedLen, int hash)
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{
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word32 len = PHASH_MAX_DIGEST_SIZE;
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word32 times;
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word32 lastLen;
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word32 lastTime;
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word32 i;
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word32 idx = 0;
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int ret;
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byte previous[PHASH_MAX_DIGEST_SIZE]; /* max size */
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byte current[PHASH_MAX_DIGEST_SIZE]; /* max size */
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word32 len = P_HASH_MAX_SIZE;
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word32 times;
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word32 lastLen;
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word32 lastTime;
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word32 i;
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word32 idx = 0;
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int ret = 0;
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#ifdef CYASSL_SMALL_STACK
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byte* previous;
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byte* current;
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Hmac* hmac;
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#else
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byte previous[P_HASH_MAX_SIZE]; /* max size */
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byte current[P_HASH_MAX_SIZE]; /* max size */
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Hmac hmac[1];
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#endif
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Hmac hmac;
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#ifdef CYASSL_SMALL_STACK
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previous = (byte*)XMALLOC(P_HASH_MAX_SIZE, NULL, DYNAMIC_TYPE_TMP_BUFFER);
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current = (byte*)XMALLOC(P_HASH_MAX_SIZE, NULL, DYNAMIC_TYPE_TMP_BUFFER);
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hmac = (Hmac*)XMALLOC(sizeof(Hmac), NULL, DYNAMIC_TYPE_TMP_BUFFER);
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if (previous == NULL || current == NULL || hmac == NULL) {
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if (previous) XFREE(previous, NULL, DYNAMIC_TYPE_TMP_BUFFER);
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if (current) XFREE(current, NULL, DYNAMIC_TYPE_TMP_BUFFER);
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if (hmac) XFREE(hmac, NULL, DYNAMIC_TYPE_TMP_BUFFER);
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return MEMORY_E;
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}
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#endif
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switch (hash) {
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#ifndef NO_MD5
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case md5_mac:
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{
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len = MD5_DIGEST_SIZE;
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hash = MD5;
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}
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break;
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case md5_mac:
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hash = MD5;
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len = MD5_DIGEST_SIZE;
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break;
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#endif
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#ifndef NO_SHA256
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case sha256_mac:
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{
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len = SHA256_DIGEST_SIZE;
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hash = SHA256;
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}
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break;
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case sha256_mac:
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hash = SHA256;
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len = SHA256_DIGEST_SIZE;
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break;
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#endif
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#ifdef CYASSL_SHA384
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case sha384_mac:
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{
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len = SHA384_DIGEST_SIZE;
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hash = SHA384;
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}
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break;
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case sha384_mac:
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hash = SHA384;
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len = SHA384_DIGEST_SIZE;
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break;
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#endif
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#ifndef NO_SHA
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case sha_mac:
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default:
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hash = SHA;
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len = SHA_DIGEST_SIZE;
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break;
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#endif
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#ifndef NO_SHA
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case sha_mac:
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default:
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{
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len = SHA_DIGEST_SIZE;
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hash = SHA;
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}
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break;
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#endif
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}
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times = resLen / len;
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times = resLen / len;
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lastLen = resLen % len;
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if (lastLen) times += 1;
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if (lastLen)
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times += 1;
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lastTime = times - 1;
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ret = HmacSetKey(&hmac, hash, secret, secLen);
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if (ret != 0)
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return ret;
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ret = HmacUpdate(&hmac, seed, seedLen); /* A0 = seed */
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if (ret != 0)
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return ret;
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ret = HmacFinal(&hmac, previous); /* A1 */
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if (ret != 0)
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return ret;
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if ((ret = HmacSetKey(hmac, hash, secret, secLen)) == 0) {
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if ((ret = HmacUpdate(hmac, seed, seedLen)) == 0) { /* A0 = seed */
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if ((ret = HmacFinal(hmac, previous)) == 0) { /* A1 */
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for (i = 0; i < times; i++) {
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ret = HmacUpdate(hmac, previous, len);
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if (ret != 0)
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break;
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ret = HmacUpdate(hmac, seed, seedLen);
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if (ret != 0)
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break;
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ret = HmacFinal(hmac, current);
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if (ret != 0)
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break;
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for (i = 0; i < times; i++) {
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ret = HmacUpdate(&hmac, previous, len);
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if (ret != 0)
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return ret;
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ret = HmacUpdate(&hmac, seed, seedLen);
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if (ret != 0)
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return ret;
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ret = HmacFinal(&hmac, current);
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if (ret != 0)
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return ret;
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if ( (i == lastTime) && lastLen)
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XMEMCPY(&result[idx], current, min(lastLen, sizeof(current)));
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else {
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XMEMCPY(&result[idx], current, len);
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idx += len;
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ret = HmacUpdate(&hmac, previous, len);
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if (ret != 0)
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return ret;
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ret = HmacFinal(&hmac, previous);
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if (ret != 0)
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return ret;
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if ((i == lastTime) && lastLen)
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XMEMCPY(&result[idx], current,
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min(lastLen, P_HASH_MAX_SIZE));
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else {
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XMEMCPY(&result[idx], current, len);
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idx += len;
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ret = HmacUpdate(hmac, previous, len);
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if (ret != 0)
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break;
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ret = HmacFinal(hmac, previous);
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if (ret != 0)
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break;
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}
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}
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}
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}
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}
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XMEMSET(previous, 0, sizeof previous);
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XMEMSET(current, 0, sizeof current);
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XMEMSET(&hmac, 0, sizeof hmac);
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return 0;
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XMEMSET(previous, 0, P_HASH_MAX_SIZE);
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XMEMSET(current, 0, P_HASH_MAX_SIZE);
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XMEMSET(hmac, 0, sizeof(Hmac));
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#ifdef CYASSL_SMALL_STACK
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XFREE(previous, NULL, DYNAMIC_TYPE_TMP_BUFFER);
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XFREE(current, NULL, DYNAMIC_TYPE_TMP_BUFFER);
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XFREE(hmac, NULL, DYNAMIC_TYPE_TMP_BUFFER);
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#endif
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return ret;
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}
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#undef P_HASH_MAX_SIZE
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#ifndef NO_OLD_TLS
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