[nginx] Stream: fixed possible use of a freed connection.

[Vladimir Homutov]

details:   http://hg.nginx.org/nginx/rev/27559d4a5151
branches:  
changeset: 7391:27559d4a5151
user:      Vladimir Homutov <vl at nginx.com>
date:      Wed Nov 07 13:22:14 2018 +0300
description:
Stream: fixed possible use of a freed connection.

The session handler may result in session termination, thus a connection
pool (from which c->udp was allocated) may be destroyed.

diffstat:

 src/event/ngx_event_udp.c |  7 ++++++-
 1 files changed, 6 insertions(+), 1 deletions(-)

diffs (24 lines):

diff -r 2e7c4c3b0644 -r 27559d4a5151 src/event/ngx_event_udp.c
--- a/src/event/ngx_event_udp.c	Tue Nov 13 14:42:47 2018 +0300
+++ b/src/event/ngx_event_udp.c	Wed Nov 07 13:22:14 2018 +0300
@@ -261,7 +261,10 @@ ngx_event_recvmsg(ngx_event_t *ev)
 
             rev->handler(rev);
 
-            c->udp->buffer = NULL;
+            if (c->udp) {
+                c->udp->buffer = NULL;
+            }
+
             rev->ready = 0;
 
             goto next;
@@ -561,6 +564,8 @@ ngx_delete_udp_connection(void *data)
     ngx_connection_t  *c = data;
 
     ngx_rbtree_delete(&c->listening->rbtree, &c->udp->node);
+
+    c->udp = NULL;
 }