Fix handling of md failure
The failure of mbedtls_md was not checked in one place. This could have led
to an incorrect computation if a hardware accelerator failed. In most cases
this would have led to the key exchange failing, so the impact would have been
a hard-to-diagnose error reported in the wrong place. If the two sides of the
key exchange failed in the same way with an output from mbedtls_md that was
independent of the input, this could have led to an apparently successful key
exchange with a predictable key, thus a glitching md accelerator could have
caused a security vulnerability.
diff --git a/library/ecjpake.c b/library/ecjpake.c
index 0cd79d0..65ba0d0 100644
--- a/library/ecjpake.c
+++ b/library/ecjpake.c
@@ -213,7 +213,7 @@
p += id_len;
/* Compute hash */
- mbedtls_md( md_info, buf, p - buf, hash );
+ MBEDTLS_MPI_CHK( mbedtls_md( md_info, buf, p - buf, hash ) );
/* Turn it into an integer mod n */
MBEDTLS_MPI_CHK( mbedtls_mpi_read_binary( h, hash,