[Asterisk-code-review] channel: Protect flags in ast waitfor nandfds operation. (asterisk[14])

[Anonymous Coward]

Anonymous Coward #1000019 has submitted this change and it was merged. ( https://gerrit.asterisk.org/4931 )

Change subject: channel: Protect flags in ast_waitfor_nandfds operation.
......................................................................


channel: Protect flags in ast_waitfor_nandfds operation.

The ast_waitfor_nandfds operation will manipulate the flags
of channels passed in. This was previously done without
the channel lock being held. This could result in incorrect
values existing for the flags if another thread manipulated
the flags at the same time.

This change locks the channel during flag manipulation.

ASTERISK-26788

Change-Id: I2c5c8edec17c9bdad4a93291576838cb552ca5ed
---
M main/channel.c
1 file changed, 6 insertions(+), 0 deletions(-)

Approvals:
  Mark Michelson: Looks good to me, approved
  George Joseph: Looks good to me, but someone else must approve
  Anonymous Coward #1000019: Verified



diff --git a/main/channel.c b/main/channel.c
index 92763f9..ac3e960 100644
--- a/main/channel.c
+++ b/main/channel.c
@@ -3130,7 +3130,9 @@
 			fdmap[max].chan = x;  /* channel x is linked to this pfds */
 			max += ast_add_fd(&pfds[max], ast_channel_fd(c[x], y));
 		}
+		ast_channel_lock(c[x]);
 		CHECK_BLOCKING(c[x]);
+		ast_channel_unlock(c[x]);
 	}
 	/* Add the individual fds */
 	for (x = 0; x < nfds; x++) {
@@ -3157,7 +3159,9 @@
 		res = ast_poll(pfds, max, rms);
 	}
 	for (x = 0; x < n; x++) {
+		ast_channel_lock(c[x]);
 		ast_clear_flag(ast_channel_flags(c[x]), AST_FLAG_BLOCKING);
+		ast_channel_unlock(c[x]);
 	}
 	if (res < 0) { /* Simulate a timeout if we were interrupted */
 		if (errno != EINTR) {
@@ -3193,12 +3197,14 @@
 		}
 		if (fdmap[x].chan >= 0) {	/* this is a channel */
 			winner = c[fdmap[x].chan];	/* override previous winners */
+			ast_channel_lock(winner);
 			if (res & POLLPRI) {
 				ast_set_flag(ast_channel_flags(winner), AST_FLAG_EXCEPTION);
 			} else {
 				ast_clear_flag(ast_channel_flags(winner), AST_FLAG_EXCEPTION);
 			}
 			ast_channel_fdno_set(winner, fdmap[x].fdno);
+			ast_channel_unlock(winner);
 		} else {			/* this is an fd */
 			if (outfd) {
 				*outfd = pfds[x].fd;

-- 
To view, visit https://gerrit.asterisk.org/4931
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Gerrit-MessageType: merged
Gerrit-Change-Id: I2c5c8edec17c9bdad4a93291576838cb552ca5ed
Gerrit-PatchSet: 1
Gerrit-Project: asterisk
Gerrit-Branch: 14
Gerrit-Owner: Joshua Colp <jcolp at digium.com>
Gerrit-Reviewer: Anonymous Coward #1000019
Gerrit-Reviewer: George Joseph <gjoseph at digium.com>
Gerrit-Reviewer: Mark Michelson <mmichelson at digium.com>