Simplify certificate curve check for 1.2
The comments were about the time we were using mbedtls_pk_ec(), which
can return NULL, which we don't want to propagate to other functions.
Now we're using mbedtls_pk_get_ec_group_id() with is a safer interface
(and works even when EC is provided by drivers).
The check for GROUP_NONE was an heritage from the previous NULL check.
However it's actually useless: if NONE were returned (which can't happen
or parsing of the certificate would have failed and we wouldn't be
here), then mbedtls_ssl_check_curve() would work and just say that the
curve wasn't valid, which is OK.
Signed-off-by: Manuel Pégourié-Gonnard <manuel.pegourie-gonnard@arm.com>
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index c1573c1..a7631bb 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -8050,35 +8050,19 @@
* Secondary checks: always done, but change 'ret' only if it was 0
*/
+ /* Check curve for ECC certs */
#if defined(PSA_WANT_KEY_TYPE_ECC_PUBLIC_KEY)
- {
- const mbedtls_pk_context *pk = &chain->pk;
-
- /* If certificate uses an EC key, make sure the curve is OK.
- * This is a public key, so it can't be opaque, so can_do() is a good
- * enough check to ensure pk_ec() is safe to use here. */
- if (mbedtls_pk_can_do(pk, MBEDTLS_PK_ECKEY)) {
- /* and in the unlikely case the above assumption no longer holds
- * we are making sure that pk_ec() here does not return a NULL
- */
- mbedtls_ecp_group_id grp_id = mbedtls_pk_get_ec_group_id(pk);
- if (grp_id == MBEDTLS_ECP_DP_NONE) {
- MBEDTLS_SSL_DEBUG_MSG(1, ("invalid group ID"));
- return MBEDTLS_ERR_SSL_INTERNAL_ERROR;
- }
- if (mbedtls_ssl_check_curve(ssl, grp_id) != 0) {
- ssl->session_negotiate->verify_result |=
- MBEDTLS_X509_BADCERT_BAD_KEY;
-
- MBEDTLS_SSL_DEBUG_MSG(1, ("bad certificate (EC key curve)"));
- if (ret == 0) {
- ret = MBEDTLS_ERR_SSL_BAD_CERTIFICATE;
- }
- }
+ if (mbedtls_pk_can_do(&chain->pk, MBEDTLS_PK_ECKEY) &&
+ mbedtls_ssl_check_curve(ssl, mbedtls_pk_get_ec_group_id(&chain->pk)) != 0) {
+ MBEDTLS_SSL_DEBUG_MSG(1, ("bad certificate (EC key curve)"));
+ ssl->session_negotiate->verify_result |= MBEDTLS_X509_BADCERT_BAD_KEY;
+ if (ret == 0) {
+ ret = MBEDTLS_ERR_SSL_BAD_CERTIFICATE;
}
}
#endif /* PSA_WANT_KEY_TYPE_ECC_PUBLIC_KEY */
+ /* Check X.509 usage extensions (keyUsage, extKeyUsage) */
if (mbedtls_ssl_check_cert_usage(chain,
ciphersuite_info,
ssl->conf->endpoint,