From b619a405a58b18747d892d39fdaa9875ebc71fd5 Mon Sep 17 00:00:00 2001
From: Russell Bryant <russell@russellbryant.com>
Date: Mon, 27 Jan 2014 01:14:19 +0000
Subject: [PATCH] Protect ast_filestream object when on a channel
The ast_filestream object gets tacked on to a channel via
chan->timingdata. It's a reference counted object, but the reference
count isn't used when putting it on a channel. It's theoretically
possible for another thread to interfere with the channel while it's
unlocked and cause the filestream to get destroyed.
Use the astobj2 reference count to make sure that as long as this code
path is holding on the ast_filestream and passing it into the file.c
playback code, that it knows it's valid.
Bug reported by Leif Madsen.
Review: https://reviewboard.asterisk.org/r/3135/
........
Merged revisions 406566 from http://svn.asterisk.org/svn/asterisk/branches/1.8
git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/11@406567 65c4cc65-6c06-0410-ace0-fbb531ad65f3
---
include/asterisk/channel.h | 5 +++++
main/channel.c | 24 ++++++++++++++++++++++++
main/file.c | 2 +-
3 files changed, 30 insertions(+), 1 deletion(-)
diff --git a/include/asterisk/channel.h b/include/asterisk/channel.h
index f072cffcea..82d3117772 100644
--- a/include/asterisk/channel.h
+++ b/include/asterisk/channel.h
@@ -901,6 +901,10 @@ enum {
* to continue.
*/
AST_FLAG_BRIDGE_DUAL_REDIRECT_WAIT = (1 << 22),
+ /*!
+ * The data on chan->timingdata is an astobj2 object.
+ */
+ AST_FLAG_TIMINGDATA_IS_AO2_OBJ = (1 << 23),
};
/*! \brief ast_bridge_config flags */
@@ -2286,6 +2290,7 @@ int ast_autoservice_ignore(struct ast_channel *chan, enum ast_frame_type ftype);
* \version 1.6.1 changed samples parameter to rate, accomodates new timing methods
*/
int ast_settimeout(struct ast_channel *c, unsigned int rate, int (*func)(const void *data), void *data);
+int ast_settimeout_full(struct ast_channel *c, unsigned int rate, int (*func)(const void *data), void *data, unsigned int is_ao2_obj);
/*!
* \brief Transfer a channel (if supported).
diff --git a/main/channel.c b/main/channel.c
index a42e73f4c4..de0affdc6a 100644
--- a/main/channel.c
+++ b/main/channel.c
@@ -3554,6 +3554,11 @@ int ast_waitfordigit(struct ast_channel *c, int ms)
}
int ast_settimeout(struct ast_channel *c, unsigned int rate, int (*func)(const void *data), void *data)
+{
+ return ast_settimeout_full(c, rate, func, data, 0);
+}
+
+int ast_settimeout_full(struct ast_channel *c, unsigned int rate, int (*func)(const void *data), void *data, unsigned int is_ao2_obj)
{
int res;
unsigned int real_rate = rate, max_rate;
@@ -3578,9 +3583,20 @@ int ast_settimeout(struct ast_channel *c, unsigned int rate, int (*func)(const v
res = ast_timer_set_rate(ast_channel_timer(c), real_rate);
+ if (ast_channel_timingdata(c) && ast_test_flag(ast_channel_flags(c), AST_FLAG_TIMINGDATA_IS_AO2_OBJ)) {
+ ao2_ref(ast_channel_timingdata(c), -1);
+ }
+
ast_channel_timingfunc_set(c, func);
ast_channel_timingdata_set(c, data);
+ if (data && is_ao2_obj) {
+ ao2_ref(data, 1);
+ ast_set_flag(ast_channel_flags(c), AST_FLAG_TIMINGDATA_IS_AO2_OBJ);
+ } else {
+ ast_clear_flag(ast_channel_flags(c), AST_FLAG_TIMINGDATA_IS_AO2_OBJ);
+ }
+
if (func == NULL && rate == 0 && ast_channel_fdno(c) == AST_TIMING_FD) {
/* Clearing the timing func and setting the rate to 0
* means that we don't want to be reading from the timingfd
@@ -3913,9 +3929,17 @@ static struct ast_frame *__ast_read(struct ast_channel *chan, int dropaudio)
/* save a copy of func/data before unlocking the channel */
ast_timing_func_t func = ast_channel_timingfunc(chan);
void *data = ast_channel_timingdata(chan);
+ int got_ref = 0;
+ if (data && ast_test_flag(ast_channel_flags(chan), AST_FLAG_TIMINGDATA_IS_AO2_OBJ)) {
+ ao2_ref(data, 1);
+ got_ref = 1;
+ }
ast_channel_fdno_set(chan, -1);
ast_channel_unlock(chan);
func(data);
+ if (got_ref) {
+ ao2_ref(data, -1);
+ }
} else {
ast_timer_set_rate(ast_channel_timer(chan), 0);
ast_channel_fdno_set(chan, -1);
diff --git a/main/file.c b/main/file.c
index c880d13cba..12ec4f1d95 100644
--- a/main/file.c
+++ b/main/file.c
@@ -845,7 +845,7 @@ static enum fsread_res ast_readaudio_callback(struct ast_filestream *s)
rate = (unsigned int) roundf(samp_rate / ((float) whennext));
- ast_settimeout(s->owner, rate, ast_fsread_audio, s);
+ ast_settimeout_full(s->owner, rate, ast_fsread_audio, s, 1);
} else {
ast_channel_streamid_set(s->owner, ast_sched_add(ast_channel_sched(s->owner), whennext / (ast_format_rate(&s->fmt->format) / 1000), ast_fsread_audio, s));
}
--
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