This is a note to let you know that I've just added the patch titled
can: bcm: fix UAF of bcm op
to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
can-bcm-fix-uaf-of-bcm-op.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From william.xuanziyang@xxxxxxxxxx Thu Jan 27 15:48:25 2022
From: Ziyang Xuan <william.xuanziyang@xxxxxxxxxx>
Date: Sat, 22 Jan 2022 18:25:06 +0800
Subject: can: bcm: fix UAF of bcm op
To: <gregkh@xxxxxxxxxxxxxxxxxxx>, <socketcan@xxxxxxxxxxxx>, <mkl@xxxxxxxxxxxxxx>, <davem@xxxxxxxxxxxxx>, <stable@xxxxxxxxxxxxxxx>
Cc: <netdev@xxxxxxxxxxxxxxx>, <linux-can@xxxxxxxxxxxxxxx>
Message-ID: <20220122102506.2898032-1-william.xuanziyang@xxxxxxxxxx>
From: Ziyang Xuan <william.xuanziyang@xxxxxxxxxx>
Stopping tasklet and hrtimer rely on the active state of tasklet and
hrtimer sequentially in bcm_remove_op(), the op object will be freed
if they are all unactive. Assume the hrtimer timeout is short, the
hrtimer cb has been excuted after tasklet conditional judgment which
must be false after last round tasklet_kill() and before condition
hrtimer_active(), it is false when execute to hrtimer_active(). Bug
is triggerd, because the stopping action is end and the op object
will be freed, but the tasklet is scheduled. The resources of the op
object will occur UAF bug.
Move hrtimer_cancel() behind tasklet_kill() and switch 'while () {...}'
to 'do {...} while ()' to fix the op UAF problem.
Fixes: a06393ed0316 ("can: bcm: fix hrtimer/tasklet termination in bcm op removal")
Reported-by: syzbot+5ca851459ed04c778d1d@xxxxxxxxxxxxxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Ziyang Xuan <william.xuanziyang@xxxxxxxxxx>
Acked-by: Oliver Hartkopp <socketcan@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/can/bcm.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)
--- a/net/can/bcm.c
+++ b/net/can/bcm.c
@@ -762,21 +762,21 @@ static struct bcm_op *bcm_find_op(struct
static void bcm_remove_op(struct bcm_op *op)
{
if (op->tsklet.func) {
- while (test_bit(TASKLET_STATE_SCHED, &op->tsklet.state) ||
- test_bit(TASKLET_STATE_RUN, &op->tsklet.state) ||
- hrtimer_active(&op->timer)) {
- hrtimer_cancel(&op->timer);
+ do {
tasklet_kill(&op->tsklet);
- }
+ hrtimer_cancel(&op->timer);
+ } while (test_bit(TASKLET_STATE_SCHED, &op->tsklet.state) ||
+ test_bit(TASKLET_STATE_RUN, &op->tsklet.state) ||
+ hrtimer_active(&op->timer));
}
if (op->thrtsklet.func) {
- while (test_bit(TASKLET_STATE_SCHED, &op->thrtsklet.state) ||
- test_bit(TASKLET_STATE_RUN, &op->thrtsklet.state) ||
- hrtimer_active(&op->thrtimer)) {
- hrtimer_cancel(&op->thrtimer);
+ do {
tasklet_kill(&op->thrtsklet);
- }
+ hrtimer_cancel(&op->thrtimer);
+ } while (test_bit(TASKLET_STATE_SCHED, &op->thrtsklet.state) ||
+ test_bit(TASKLET_STATE_RUN, &op->thrtsklet.state) ||
+ hrtimer_active(&op->thrtimer));
}
if ((op->frames) && (op->frames != &op->sframe))
Patches currently in stable-queue which might be from william.xuanziyang@xxxxxxxxxx are
queue-4.14/can-bcm-fix-uaf-of-bcm-op.patch
