Hashing API may produce collisions

[qwepoizt]

@markus2330 wrote:
src/libs/ease/hash.c produces collisions in scenarios like key = "keyvalue", value = "" vs. key = "key" and value = "value".

Expected behavior: With different KeySet the sha256 should be different, especially the ones which are only slightly different.

@qwepoizt wrote:
This was noticed by @markus2330 in #4047 (comment) .

I.e. the following test case fails, because string1 is equal to string2 even though the two should be different:

/**
 * Test whether streaming API is aware of character order.
 */
static void test_streaming_aware_of_order (void)
{
	// Initialize sha_256 for streaming
	uint8_t hash1[SIZE_OF_SHA_256_HASH];
	struct Sha_256 sha_256_1;
	sha_256_init (&sha_256_1, hash1);

	const char * key = "key";
	const char * value = "value";
	
	sha_256_write (&sha_256_1, key, strlen(key));
	sha_256_write (&sha_256_1, value, strlen(value));
	sha_256_close (&sha_256_1);
	
	char string1[65];
	hash_to_string (string1, hash1);

	// Reinitialize sha_256 for streaming
	uint8_t hash2[SIZE_OF_SHA_256_HASH];
	struct Sha_256 sha_256_2;
	sha_256_init (&sha_256_2, hash2);
	const char * keyvalue = "keyvalue";

	sha_256_write (&sha_256_2, keyvalue, strlen(keyvalue));
	sha_256_close (&sha_256_2);

	char string2[65];
	hash_to_string (string2, hash2);

	succeed_if (strcmp(string1, string2) == 0, "streaming API of sha_256 is not aware of order!");
}

System Information

• Elektra Version: master