Don't send a warning alert in TLSv1.3

TLSv1.3 ignores the alert level, so we should suppress sending of
warning only alerts.

Fixes #6211

Reviewed-by: Andy Polyakov <appro@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/6370)

diff --git a/ssl/statem/extensions.c b/ssl/statem/extensions.c
index 8885e5e0d7d496405232aa8b53ffb00e3ed09301..496039e3d4094f5ee7be448689bdb9706a9ce4cb 100644 (file)
--- a/ssl/statem/extensions.c
+++ b/ssl/statem/extensions.c
@@ -984,7 +984,9 @@ static int final_server_name(SSL *s, unsigned int context, int sent)
         return 0;
 
     case SSL_TLSEXT_ERR_ALERT_WARNING:
         return 0;
 
     case SSL_TLSEXT_ERR_ALERT_WARNING:

-        ssl3_send_alert(s, SSL3_AL_WARNING, altmp);
+        /* TLSv1.3 doesn't have warning alerts so we suppress this */
+        if (!SSL_IS_TLS13(s))
+            ssl3_send_alert(s, SSL3_AL_WARNING, altmp);

         return 1;
 
     case SSL_TLSEXT_ERR_NOACK:
         return 1;
 
     case SSL_TLSEXT_ERR_NOACK: