This is a note to let you know that I've just added the patch titled
posix-timer: Don't call idr_find() with out-of-range ID
to the 3.4-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:
posix-timer-don-t-call-idr_find-with-out-of-range-id.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From e182bb38d7db7494fa5dcd82da17fe0dedf60ecf Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@xxxxxxxxxx>
Date: Wed, 20 Feb 2013 15:24:12 -0800
Subject: posix-timer: Don't call idr_find() with out-of-range ID
From: Tejun Heo <tj@xxxxxxxxxx>
commit e182bb38d7db7494fa5dcd82da17fe0dedf60ecf upstream.
When idr_find() was fed a negative ID, it used to look up the ID
ignoring the sign bit before recent ("idr: remove MAX_IDR_MASK and
move left MAX_IDR_* into idr.c") patch. Now a negative ID triggers
a WARN_ON_ONCE().
__lock_timer() feeds timer_id from userland directly to idr_find()
without sanitizing it which can trigger the above malfunctions. Add a
range check on @timer_id before invoking idr_find() in __lock_timer().
While timer_t is defined as int by all archs at the moment, Andrew
worries that it may be defined as a larger type later on. Make the
test cover larger integers too so that it at least is guaranteed to
not return the wrong timer.
Note that WARN_ON_ONCE() in idr_find() on id < 0 is transitional
precaution while moving away from ignoring MSB. Once it's gone we can
remove the guard as long as timer_t isn't larger than int.
Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>nnn
Reported-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20130220232412.GL3570@xxxxxxxxxxxxxx
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/posix-timers.c | 7 +++++++
1 file changed, 7 insertions(+)
--- a/kernel/posix-timers.c
+++ b/kernel/posix-timers.c
@@ -639,6 +639,13 @@ static struct k_itimer *__lock_timer(tim
{
struct k_itimer *timr;
+ /*
+ * timer_t could be any type >= int and we want to make sure any
+ * @timer_id outside positive int range fails lookup.
+ */
+ if ((unsigned long long)timer_id > INT_MAX)
+ return NULL;
+
rcu_read_lock();
timr = idr_find(&posix_timers_id, (int)timer_id);
if (timr) {
Patches currently in stable-queue which might be from tj@xxxxxxxxxx are
queue-3.4/posix-timer-don-t-call-idr_find-with-out-of-range-id.patch
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