apps/app_queue: Prevent possible crash when evaluating queue penalty rules

Although it only occurred once, a crash occurred when a queue attempted to
evaluate a queue penalty rule that appeared to have already been destroyed.
In many locations in app_queue, a test is done to see if qe->pr is NULL;
however, when we dispose of a queue's penalty rules, we don't set the pointer
to NULL after free'ing it. This patch does that to prevent any dangling
pointers from lingering on the queue object.

Review: https://reviewboard.asterisk.org/r/4522

ASTERISK-23319 #close
Reported by: Vadim
patches:
  rb4552.patch submitted by Stefan Engström (License 6691)
........

Merged revisions 434448 from http://svn.asterisk.org/svn/asterisk/branches/11

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/13@434449 65c4cc65-6c06-0410-ace0-fbb531ad65f3

diff --git a/apps/app_queue.c b/apps/app_queue.c
index 2e6b10c4d00166616e963fc17f36029e0a5dbc10..6d45be3705d59557cc0f2684a0e69de67e845524 100644 (file)
--- a/apps/app_queue.c
+++ b/apps/app_queue.c
@@ -3900,6 +3900,7 @@ static void leave_queue(struct queue_ent *qe)
                        while ((pr_iter = AST_LIST_REMOVE_HEAD(&qe->qe_rules, list))) {
                                ast_free(pr_iter);
                        }
+                       qe->pr = NULL;
                        snprintf(posstr, sizeof(posstr), "%d", qe->pos);
                        pbx_builtin_setvar_helper(qe->chan, "QUEUEPOSITION", posstr);
                } else {