Fix ASAN error for `psa_cipher_update`
The ASAN gives an error for `psa_cipher_update` when the `input_length`
is 0 and the `input` buffer is `NULL`. The root cause of this issue is
`mbedtls_cipher_update` always need a valid pointer for the
input buffer even if the length is 0.
This fix avoids the `mbedtls_cipher_update` to be called if the
input buffer length is 0.
Signed-off-by: Gabor Mezei <gabor.mezei@arm.com>
diff --git a/library/psa_crypto_cipher.c b/library/psa_crypto_cipher.c
index 3132854..d70a275 100644
--- a/library/psa_crypto_cipher.c
+++ b/library/psa_crypto_cipher.c
@@ -532,7 +532,11 @@
output_length);
} else
#endif /* MBEDTLS_PSA_BUILTIN_ALG_ECB_NO_PADDING */
- {
+ if (input_length == 0) {
+ /* There is no input, nothing to be done */
+ *output_length = 0;
+ status = PSA_SUCCESS;
+ } else {
status = mbedtls_to_psa_error(
mbedtls_cipher_update(&operation->ctx.cipher, input,
input_length, output, output_length));