Enable key usage checks in the client side of RSA ciphersuites

diff --git a/lib/auth/rsa.c b/lib/auth/rsa.c
index e43b2968716804c61628eaf4ea0d8284ccfa29d8..d8d0edf29acae5dffb26fc4f40f3ead067ecca7e 100644 (file)
--- a/lib/auth/rsa.c
+++ b/lib/auth/rsa.c
@@ -62,6 +62,25 @@ const mod_auth_st rsa_auth_struct = {
        _gnutls_proc_cert_cert_req      /* proc server cert request */
 };
 
+static
+int check_key_usage_for_enc(gnutls_session_t session, unsigned key_usage)
+{
+       if (key_usage != 0) {
+               if (!(key_usage & GNUTLS_KEY_KEY_ENCIPHERMENT) && !(key_usage & GNUTLS_KEY_KEY_AGREEMENT)) {
+                       gnutls_assert();
+                       if (session->internals.priorities.allow_key_usage_violation == 0) {
+                               _gnutls_audit_log(session,
+                                         "Peer's certificate does not allow encryption. Key usage violation detected.\n");
+                               return GNUTLS_E_KEY_USAGE_VIOLATION;
+                       } else {
+                               _gnutls_audit_log(session,
+                                         "Peer's certificate does not allow encryption. Key usage violation detected (ignored).\n");
+                       }
+               }
+       }
+       return 0;
+}
+
 /* This function reads the RSA parameters from peer's certificate;
  */
 int
@@ -70,6 +89,7 @@ _gnutls_get_public_rsa_params(gnutls_session_t session,
 {
        int ret;
        cert_auth_info_t info;
+       unsigned key_usage;
        gnutls_pcert_st peer_cert;
 
        /* normal non export case */
@@ -91,6 +111,14 @@ _gnutls_get_public_rsa_params(gnutls_session_t session,
                return ret;
        }
 
+       gnutls_pubkey_get_key_usage(peer_cert.pubkey, &key_usage);
+
+       ret = check_key_usage_for_enc(session, key_usage);
+       if (ret < 0) {
+               gnutls_assert();
+               goto cleanup2;
+       }
+
        gnutls_pk_params_init(params);
 
        ret = _gnutls_pubkey_get_mpis(peer_cert.pubkey, params);