From 178b9be8eccffca66434299bf986494c449b10ee Mon Sep 17 00:00:00 2001
From: Roberto Guimaraes <rguimaraes@fastly.com>
Date: Wed, 8 Mar 2017 09:54:04 -0500
Subject: [PATCH] Prevent undefined behavior in memcpy call.

CLA: trivial

Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2750)
(cherry picked from commit 6aad9393680ccde591905c8d71da92a241756394)
---
 ssl/ssl_sess.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/ssl/ssl_sess.c b/ssl/ssl_sess.c
index c3369a44ae..f50f514212 100644
--- a/ssl/ssl_sess.c
+++ b/ssl/ssl_sess.c
@@ -1006,7 +1006,8 @@ int SSL_SESSION_set1_id_context(SSL_SESSION *s, const unsigned char *sid_ctx,
         return 0;
     }
     s->sid_ctx_length = sid_ctx_len;
-    memcpy(s->sid_ctx, sid_ctx, sid_ctx_len);
+    if (s->sid_ctx != sid_ctx)
+        memcpy(s->sid_ctx, sid_ctx, sid_ctx_len);
 
     return 1;
 }
-- 
2.25.1