From: Matt Caswell <matt@openssl.org>
Date: Mon, 9 Mar 2015 16:09:04 +0000 (+0000)
Subject: Fix Seg fault in DTLSv1_listen
X-Git-Tag: OpenSSL_1_1_0-pre1~1514
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=e83ee04bb7de800cdb71d522fa562e99328003a3;p=openssl

Fix Seg fault in DTLSv1_listen

The DTLSv1_listen function is intended to be stateless and processes
the initial ClientHello from many peers. It is common for user code to
loop over the call to DTLSv1_listen until a valid ClientHello is received
with an associated cookie. A defect in the implementation of DTLSv1_listen
means that state is preserved in the SSL object from one invokation to the
next that can lead to a segmentation fault. Erorrs processing the initial
ClientHello can trigger this scenario. An example of such an error could
be that a DTLS1.0 only client is attempting to connect to a DTLS1.2 only
server.

CVE-2015-0207

Reviewed-by: Richard Levitte <levitte@openssl.org>
---

diff --git a/ssl/d1_lib.c b/ssl/d1_lib.c
index 626cecbcbf..e9a2fc5bf8 100644
--- a/ssl/d1_lib.c
+++ b/ssl/d1_lib.c
@@ -546,6 +546,9 @@ int dtls1_listen(SSL *s, struct sockaddr *client)
 {
     int ret;
 
+    /* Ensure there is no state left over from a previous invocation */
+    SSL_clear(s);
+
     SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE);
     s->d1->listen = 1;