Don't send a status_request extension in a CertificateRequest message

If a TLSv1.3 server configured to respond to the status_request extension
also attempted to send a CertificateRequest then it was incorrectly
inserting a non zero length status_request extension into that message.

The TLSv1.3 RFC does allow that extension in that message but it must
always be zero length.

In fact we should not be sending the extension at all in that message
because we don't support it.

Fixes #9767

Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
(Merged from https://github.com/openssl/openssl/pull/9780)

(cherry picked from commit debb64a0ca43969eb3f043aa8895a4faa7f12b6e)

diff --git a/ssl/statem/extensions_srvr.c b/ssl/statem/extensions_srvr.c
index ff4287c584b76fdd2c5ab635b7dde6a755353116..ab5453f63eccdb2197ad5eead52556218c706bc3 100644 (file)
--- a/ssl/statem/extensions_srvr.c
+++ b/ssl/statem/extensions_srvr.c
@@ -1487,6 +1487,10 @@ EXT_RETURN tls_construct_stoc_status_request(SSL *s, WPACKET *pkt,
                                              unsigned int context, X509 *x,
                                              size_t chainidx)
 {
+    /* We don't currently support this extension inside a CertificateRequest */
+    if (context == SSL_EXT_TLS1_3_CERTIFICATE_REQUEST)
+        return EXT_RETURN_NOT_SENT;
+
     if (!s->ext.status_expected)
         return EXT_RETURN_NOT_SENT;