Fix incorrect buffer size

lib/source/cbc_mode.c

@@ -91,7 +91,7 @@ int tc_cbc_mode_decrypt(uint8_t *out, unsigned int outlen, const uint8_t *in,
 	    outlen == 0 ||
 	    (inlen % TC_AES_BLOCK_SIZE) != 0 ||
 	    (outlen % TC_AES_BLOCK_SIZE) != 0 ||
-	    outlen != inlen - TC_AES_BLOCK_SIZE) {
+	    outlen != inlen) {
 		return TC_CRYPTO_FAIL;
 	}
 
@@ -101,7 +101,7 @@ int tc_cbc_mode_decrypt(uint8_t *out, unsigned int outlen, const uint8_t *in,
 	 * that would not otherwise be possible.
 	 */
 	p = iv;
-	for (n = m = 0; n < inlen; ++n) {
+	for (n = m = 0; n < outlen; ++n) {
 		if ((n % TC_AES_BLOCK_SIZE) == 0) {
 			(void)tc_aes_decrypt(buffer, in, sched);
 			in += TC_AES_BLOCK_SIZE;

tests/test_cbc_mode.c

@@ -132,10 +132,9 @@ int test_1_and_2(void)
 	(void)tc_aes128_set_decrypt_key(&a, key);
 
 	p = &encrypted[TC_AES_BLOCK_SIZE];
-	length = ((unsigned int) sizeof(encrypted)) - TC_AES_BLOCK_SIZE;
+	length = ((unsigned int) sizeof(encrypted));
 
-	if (tc_cbc_mode_decrypt(decrypted, length - TC_AES_BLOCK_SIZE, p, length,
-				encrypted, &a) == 0) {
+	if (tc_cbc_mode_decrypt(decrypted, length, p, length, encrypted, &a) == 0) {
 		TC_ERROR("CBC test #2 (decryption SP 800-38a tests) failed in. "
 			 "%s\n", __func__);
 		result = TC_FAIL;
@@ -161,7 +160,7 @@ int main(void)
 
 	TC_PRINT("Performing CBC tests:\n");
 	result = test_1_and_2();
-	if (result == TC_FAIL) {	
+	if (result == TC_FAIL) {
 		/* terminate test */
 		TC_ERROR("CBC test #1 failed.\n");
 		goto exitTest;