Make sure we call ssl3_digest_cached_records() when necessary

Having received a ClientKeyExchange message instead of a Certificate we
know that we are not going to receive a CertificateVerify message. This
means we can free up the handshake_buffer. However we better call
ssl3_digest_cached_records() instead of just freeing it up, otherwise we
later try and use it anyway and a core dump results. This could happen,
for example, in SSLv3 where we send a CertificateRequest but the client
sends no Certificate message at all. This is valid in SSLv3 (in TLS
clients are required to send an empty Certificate message).

Found using the BoringSSL test suite.

Reviewed-by: Emilia Käsper <emilia@openssl.org>

diff --git a/ssl/statem/statem_srvr.c b/ssl/statem/statem_srvr.c
index c0115232282491337de4d71ca31472f6594e5367..477af27108d8a29f9ea40e08779c469fecd9af49 100644 (file)
--- a/ssl/statem/statem_srvr.c
+++ b/ssl/statem/statem_srvr.c
@@ -2587,17 +2587,16 @@ WORK_STATE tls_post_process_client_key_exchange(SSL *s, WORK_STATE wst)
     }
 #endif
 
-    if (s->statem.no_cert_verify) {
-        /* No certificate verify so we no longer need the handshake_buffer */
-        BIO_free(s->s3->handshake_buffer);
-        s->s3->handshake_buffer = NULL;
+    if (s->statem.no_cert_verify || !s->session->peer) {
+        /* No certificate verify or no peer certificate so we no longer need the
+         * handshake_buffer
+         */
+        if (!ssl3_digest_cached_records(s, 0)) {
+            ossl_statem_set_error(s);
+            return WORK_ERROR;
+        }
         return WORK_FINISHED_CONTINUE;
     } else {
-        if (!s->session->peer) {
-            /* No peer certificate so we no longer need the handshake_buffer */
-            BIO_free(s->s3->handshake_buffer);
-            return WORK_FINISHED_CONTINUE;
-        }
         if (!s->s3->handshake_buffer) {
             SSLerr(SSL_F_TLS_POST_PROCESS_CLIENT_KEY_EXCHANGE,
                    ERR_R_INTERNAL_ERROR);