[Asterisk-code-review] chan pjsip: Use session for retrieving CHANNEL() information. (asterisk[13])

[Joshua Colp]

Joshua Colp has uploaded a new change for review. ( https://gerrit.asterisk.org/4671 )

Change subject: chan_pjsip: Use session for retrieving CHANNEL() information.
......................................................................

chan_pjsip: Use session for retrieving CHANNEL() information.

The CHANNEL() dialplan function implementation for PJSIP allows
querying of PJSIP specific information. This used the channel
passed in to get the PJSIP session and associated information.
It is possible for this channel to be masqueraded and end
up as a different channel type by the time the information
request is actually acted upon.

This change retrieves the PJSIP session safely and accesses
data from it (including channel). This provides a guarantee
that the session and channel will not be altered when the
request is being acted upon.

ASTERISK-26673

Change-Id: I335e12b89e1820cafdd92b3e7526b8ba649eb7e6
---
M channels/pjsip/dialplan_functions.c
1 file changed, 21 insertions(+), 31 deletions(-)


  git pull ssh://gerrit.asterisk.org:29418/asterisk refs/changes/71/4671/1

diff --git a/channels/pjsip/dialplan_functions.c b/channels/pjsip/dialplan_functions.c
index ecf5105..79272db 100644
--- a/channels/pjsip/dialplan_functions.c
+++ b/channels/pjsip/dialplan_functions.c
@@ -722,7 +722,7 @@
 
 /*! \brief Struct used to push function arguments to task processor */
 struct pjsip_func_args {
-	struct ast_channel *chan;
+	struct ast_sip_session *session;
 	const char *param;
 	const char *type;
 	const char *field;
@@ -737,49 +737,31 @@
 	struct pjsip_func_args *func_args = data;
 
 	if (!strcmp(func_args->param, "rtp")) {
-		func_args->ret = channel_read_rtp(func_args->chan, func_args->type,
+		func_args->ret = channel_read_rtp(func_args->session->channel, func_args->type,
 		                                  func_args->field, func_args->buf,
 		                                  func_args->len);
 	} else if (!strcmp(func_args->param, "rtcp")) {
-		func_args->ret = channel_read_rtcp(func_args->chan, func_args->type,
+		func_args->ret = channel_read_rtcp(func_args->session->channel, func_args->type,
 		                                   func_args->field, func_args->buf,
 		                                   func_args->len);
 	} else if (!strcmp(func_args->param, "endpoint")) {
-		struct ast_sip_channel_pvt *pvt = ast_channel_tech_pvt(func_args->chan);
-
-		if (!pvt) {
-			ast_log(AST_LOG_WARNING, "Channel %s has no pvt!\n", ast_channel_name(func_args->chan));
+		if (!func_args->session->endpoint) {
+			ast_log(AST_LOG_WARNING, "Channel %s has no endpoint!\n", ast_channel_name(func_args->session->channel));
 			return -1;
 		}
-		if (!pvt->session || !pvt->session->endpoint) {
-			ast_log(AST_LOG_WARNING, "Channel %s has no endpoint!\n", ast_channel_name(func_args->chan));
-			return -1;
-		}
-		snprintf(func_args->buf, func_args->len, "%s", ast_sorcery_object_get_id(pvt->session->endpoint));
+		snprintf(func_args->buf, func_args->len, "%s", ast_sorcery_object_get_id(func_args->session->endpoint));
 	} else if (!strcmp(func_args->param, "contact")) {
-		struct ast_sip_channel_pvt *pvt = ast_channel_tech_pvt(func_args->chan);
-
-		if (!pvt) {
-			ast_log(AST_LOG_WARNING, "Channel %s has no pvt!\n", ast_channel_name(func_args->chan));
-			return -1;
-		}
-		if (!pvt->session || !pvt->session->contact) {
+		if (!func_args->session->contact) {
 			return 0;
 		}
-		snprintf(func_args->buf, func_args->len, "%s", ast_sorcery_object_get_id(pvt->session->contact));
+		snprintf(func_args->buf, func_args->len, "%s", ast_sorcery_object_get_id(func_args->session->contact));
 	} else if (!strcmp(func_args->param, "aor")) {
-		struct ast_sip_channel_pvt *pvt = ast_channel_tech_pvt(func_args->chan);
-
-		if (!pvt) {
-			ast_log(AST_LOG_WARNING, "Channel %s has no pvt!\n", ast_channel_name(func_args->chan));
-			return -1;
-		}
-		if (!pvt->session || !pvt->session->aor) {
+		if (!func_args->session->aor) {
 			return 0;
 		}
-		snprintf(func_args->buf, func_args->len, "%s", ast_sorcery_object_get_id(pvt->session->aor));
+		snprintf(func_args->buf, func_args->len, "%s", ast_sorcery_object_get_id(func_args->session->aor));
 	} else if (!strcmp(func_args->param, "pjsip")) {
-		func_args->ret = channel_read_pjsip(func_args->chan, func_args->type,
+		func_args->ret = channel_read_pjsip(func_args->session->channel, func_args->type,
 		                                    func_args->field, func_args->buf,
 		                                    func_args->len);
 	} else {
@@ -816,29 +798,37 @@
 
 	AST_STANDARD_APP_ARGS(args, parse);
 
+	ast_channel_lock(chan);
+
 	/* Sanity check */
 	if (strcmp(ast_channel_tech(chan)->type, "PJSIP")) {
 		ast_log(LOG_WARNING, "Cannot call %s on a non-PJSIP channel\n", cmd);
+		ast_channel_unlock(chan);
 		return 0;
 	}
 
 	if (!channel) {
 		ast_log(AST_LOG_WARNING, "Channel %s has no pvt!\n", ast_channel_name(chan));
+		ast_channel_unlock(chan);
 		return -1;
 	}
 
+	func_args.session = ao2_bump(channel->session);
+	ast_channel_unlock(chan);
+
 	memset(buf, 0, len);
 
-	func_args.chan = chan;
 	func_args.param = args.param;
 	func_args.type = args.type;
 	func_args.field = args.field;
 	func_args.buf = buf;
 	func_args.len = len;
-	if (ast_sip_push_task_synchronous(channel->session->serializer, read_pjsip, &func_args)) {
+	if (ast_sip_push_task_synchronous(func_args.session->serializer, read_pjsip, &func_args)) {
 		ast_log(LOG_WARNING, "Unable to read properties of channel %s: failed to push task\n", ast_channel_name(chan));
+		ao2_ref(func_args.session, -1);
 		return -1;
 	}
+	ao2_ref(func_args.session, -1);
 
 	return func_args.ret;
 }

-- 
To view, visit https://gerrit.asterisk.org/4671
To unsubscribe, visit https://gerrit.asterisk.org/settings

Gerrit-MessageType: newchange
Gerrit-Change-Id: I335e12b89e1820cafdd92b3e7526b8ba649eb7e6
Gerrit-PatchSet: 1
Gerrit-Project: asterisk
Gerrit-Branch: 13
Gerrit-Owner: Joshua Colp <jcolp at digium.com>