hkdf(): Apply code changes requested by nikic

Author: narfbg

ext/hash/hash.c

@@ -613,13 +613,13 @@ PHP_FUNCTION(hkdf)
 		return;
 	}
 
-	ops = php_hash_fetch_ops(algo->val, algo->len);
+	ops = php_hash_fetch_ops(ZSTR_VAL(algo), ZSTR_LEN(algo));
 	if (!ops) {
-		php_error_docref(NULL, E_WARNING, "Unknown hashing algorithm: %s", algo->val, algo->len);
+		php_error_docref(NULL, E_WARNING, "Unknown hashing algorithm: %s", ZSTR_VAL(algo), ZSTR_LEN(algo));
 		RETURN_FALSE;
 	}
 
-	if (ikm->len <= 0) {
+	if (ZSTR_LEN(ikm) == 0) {
 		php_error_docref(NULL, E_WARNING, "Input keying material cannot be empty");
 		RETURN_FALSE;
 	}
@@ -636,26 +636,23 @@ PHP_FUNCTION(hkdf)
 		RETURN_FALSE;
 	}
 
-	if (salt != NULL && salt->len > 0) {
-		computed_salt = emalloc(salt->len);
-		memcpy(computed_salt, salt->val, salt->len);
+	if (salt != NULL && ZSTR_LEN(salt) > 0) {
+		computed_salt = emalloc(ZSTR_LEN(salt));
+		memcpy(computed_salt, ZSTR_VAL(salt), ZSTR_LEN(salt));
 	}
 	else {
 		computed_salt = emalloc(ops->digest_size);
-		for (i = 0; i < ops->digest_size; i++)
-		{
-			computed_salt[i] = 0x00;
-		}
+		memset(computed_salt, 0x00, ops->digest_size);
 	}
 
 	context = emalloc(ops->context_size);
 
 	// Extract
 	ops->hash_init(context);
 	K = emalloc(ops->block_size);
-	php_hash_hmac_prep_key(K, ops, context, computed_salt, (salt != NULL && salt->len ? salt->len : ops->digest_size));
-	prk = safe_emalloc(ops->digest_size, ops->digest_size, 0);
-	php_hash_hmac_round(prk, ops, context, K, ikm->val, ikm->len);
+	php_hash_hmac_prep_key(K, ops, context, computed_salt, (salt != NULL && ZSTR_LEN(salt) ? ZSTR_LEN(salt) : ops->digest_size));
+	prk = safe_emalloc(ops->block_size, 1, 0);
+	php_hash_hmac_round(prk, ops, context, K, ZSTR_VAL(ikm), ZSTR_LEN(ikm));
 	php_hash_string_xor_char(K, K, 0x6A, ops->block_size);
 	php_hash_hmac_round(prk, ops, context, K, prk, ops->digest_size);
 	ZEND_SECURE_ZERO(K, ops->block_size);
@@ -664,7 +661,7 @@ PHP_FUNCTION(hkdf)
 	// Expand
 	returnval = zend_string_alloc(length, 0);
 	digest = emalloc(ops->digest_size);
-	for (i = 1, rounds = ceil((float) length / (float) ops->digest_size); i <= rounds; i++) {
+	for (i = 1, rounds = (length - 1) / ops->digest_size + 1; i <= rounds; i++) {
 		// chr(i)
 		unsigned char c[1];
 		c[0] = (i & 0xFF);
@@ -677,8 +674,8 @@ PHP_FUNCTION(hkdf)
 			ops->hash_update(context, digest, ops->digest_size);
 		}
 
-		if (info != NULL && info->len > 0) {
-			ops->hash_update(context, info->val, info->len);
+		if (info != NULL && ZSTR_LEN(info) > 0) {
+			ops->hash_update(context, ZSTR_VAL(info), ZSTR_LEN(info));
 		}
 
 		ops->hash_update(context, c, 1);