Fix deadlock potential with ast_set_hangupsource() calls.

Calling ast_set_hangupsource() with the channel lock held can result in a
deadlock because the function also locks the bridged channel.

(issue ASTERISK-19537)

(closes issue AST-891)
Reported by: Guenther Kelleter
Tested by: Guenther Kelleter

(closes issue ASTERISK-19801)
Reported by: Alec Davis
........

Merged revisions 368759 from http://svn.asterisk.org/svn/asterisk/branches/1.8
........

Merged revisions 368760 from http://svn.asterisk.org/svn/asterisk/branches/10


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@368772 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 41 insertions, 10 deletions

diff --git a/channels/chan_sip.c b/channels/chan_sip.c
index d8c9f3958..934f8a611 100644
--- a/channels/chan_sip.c
+++ b/channels/chan_sip.c
@@ -20973,6 +20973,41 @@ static void handle_response_publish(struct sip_pvt *p, int resp, const char *res
 	}
 }
 
+/*!
+ * \internal
+ * \brief Set hangup source and cause.
+ *
+ * \param p SIP private.
+ * \param cause Hangup cause to queue.  Zero if no cause.
+ *
+ * \pre p and p->owner are locked.
+ *
+ * \return Nothing
+ */
+static void sip_queue_hangup_cause(struct sip_pvt *p, int cause)
+{
+	struct ast_channel *owner = p->owner;
+	const char *name = ast_strdupa(ast_channel_name(owner));
+
+	/* Cannot hold any channel/private locks when calling. */
+	ast_channel_ref(owner);
+	ast_channel_unlock(owner);
+	sip_pvt_unlock(p);
+	ast_set_hangupsource(owner, name, 0);
+	if (cause) {
+		ast_queue_hangup_with_cause(owner, cause);
+	} else {
+		ast_queue_hangup(owner);
+	}
+	ast_channel_unref(owner);
+
+	/* Relock things. */
+	owner = sip_pvt_lock_full(p);
+	if (owner) {
+		ast_channel_unref(owner);
+	}
+}
+
 /*! \brief Handle SIP response to INVITE dialogue */
 static void handle_response_invite(struct sip_pvt *p, int resp, const char *rest, struct sip_request *req, uint32_t seqno)
 {
@@ -21339,16 +21374,14 @@ static void handle_response_invite(struct sip_pvt *p, int resp, const char *rest
 		xmitres = transmit_request(p, SIP_ACK, seqno, XMIT_UNRELIABLE, FALSE);
 		ast_log(LOG_WARNING, "Received response: \"Forbidden\" from '%s'\n", sip_get_header(&p->initreq, "From"));
 		if (!req->ignore && p->owner) {
-			ast_set_hangupsource(p->owner, ast_channel_name(p->owner), 0);
-			ast_queue_hangup_with_cause(p->owner, hangup_sip2cause(resp));
+			sip_queue_hangup_cause(p, hangup_sip2cause(resp));
 		}
 		break;
 
 	case 404: /* Not found */
 		xmitres = transmit_request(p, SIP_ACK, seqno, XMIT_UNRELIABLE, FALSE);
 		if (p->owner && !req->ignore) {
-			ast_set_hangupsource(p->owner, ast_channel_name(p->owner), 0);
-			ast_queue_hangup_with_cause(p->owner, hangup_sip2cause(resp));
+			sip_queue_hangup_cause(p, hangup_sip2cause(resp));
 		}
 		break;
 
@@ -24882,11 +24915,10 @@ static int handle_request_cancel(struct sip_pvt *p, struct sip_request *req)
 
 	stop_media_flows(p); /* Immediately stop RTP, VRTP and UDPTL as applicable */
 	if (p->owner) {
-		ast_set_hangupsource(p->owner, ast_channel_name(p->owner), 0);
-		ast_queue_hangup(p->owner);
-	}
-	else
+		sip_queue_hangup_cause(p, 0);
+	} else {
 		sip_scheddestroy(p, DEFAULT_TRANS_TIMEOUT);
+	}
 	if (ast_str_strlen(p->initreq.data) > 0) {
 		struct sip_pkt *pkt, *prev_pkt;
 		/* If the CANCEL we are receiving is a retransmission, and we already have scheduled
@@ -25040,8 +25072,7 @@ static int handle_request_bye(struct sip_pvt *p, struct sip_request *req)
 				ast_queue_hangup_with_cause(p->owner, AST_CAUSE_PROTOCOL_ERROR);
 		}
 	} else if (p->owner) {
-		ast_set_hangupsource(p->owner, ast_channel_name(p->owner), 0);
-		ast_queue_hangup(p->owner);
+		sip_queue_hangup_cause(p, 0);
 		sip_scheddestroy_final(p, DEFAULT_TRANS_TIMEOUT);
 		ast_debug(3, "Received bye, issuing owner hangup\n");
 	} else {