linux-kernel - [ 160/171] libceph: recheck con state after allocating incoming message

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20121122004049.411749694@linuxfoundation.org>
Date:	Wed, 21 Nov 2012 16:41:46 -0800
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	alan@...rguk.ukuu.org.uk, Sage Weil <sage@...tank.com>,
	Alex Elder <elder@...tank.com>
Subject: [ 160/171] libceph: recheck con state after allocating incoming message

3.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Sage Weil <sage@...tank.com>

(cherry picked from commit 6139919133377652992a5fe134e22abce3e9c25e)

We drop the lock when calling the ->alloc_msg() con op, which means
we need to (a) not clobber con->in_msg without the mutex held, and (b)
we need to verify that we are still in the OPEN state when we retake
it to avoid causing any mayhem.  If the state does change, -EAGAIN
will get us back to con_work() and loop.

Signed-off-by: Sage Weil <sage@...tank.com>
Reviewed-by: Alex Elder <elder@...tank.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 net/ceph/messenger.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -2735,9 +2735,16 @@ static int ceph_con_in_msg_alloc(struct
 	BUG_ON(con->in_msg != NULL);
 
 	if (con->ops->alloc_msg) {
+		struct ceph_msg *msg;
+
 		mutex_unlock(&con->mutex);
-		con->in_msg = con->ops->alloc_msg(con, hdr, skip);
+		msg = con->ops->alloc_msg(con, hdr, skip);
 		mutex_lock(&con->mutex);
+		if (con->state != CON_STATE_OPEN) {
+			ceph_msg_put(msg);
+			return -EAGAIN;
+		}
+		con->in_msg = msg;
 		if (con->in_msg) {
 			con->in_msg->con = con->ops->get(con);
 			BUG_ON(con->in_msg->con == NULL);


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/