This is a note to let you know that I've just added the patch titled
rcu-tasks: Fix show_rcu_tasks_trace_gp_kthread buffer overflow
to the 6.8-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:
rcu-tasks-fix-show_rcu_tasks_trace_gp_kthread-buffer.patch
and it can be found in the queue-6.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit acc017d28b4e3990e90c1b9cb9c5723a5913bb92
Author: Nikita Kiryushin <kiryushin@xxxxxxxx>
Date: Wed Mar 27 20:47:47 2024 +0300
rcu-tasks: Fix show_rcu_tasks_trace_gp_kthread buffer overflow
[ Upstream commit cc5645fddb0ce28492b15520306d092730dffa48 ]
There is a possibility of buffer overflow in
show_rcu_tasks_trace_gp_kthread() if counters, passed
to sprintf() are huge. Counter numbers, needed for this
are unrealistically high, but buffer overflow is still
possible.
Use snprintf() with buffer size instead of sprintf().
Found by Linux Verification Center (linuxtesting.org) with SVACE.
Fixes: edf3775f0ad6 ("rcu-tasks: Add count for idle tasks on offline CPUs")
Signed-off-by: Nikita Kiryushin <kiryushin@xxxxxxxx>
Reviewed-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index 732ad5b39946a..3f64268fe9ead 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -1941,7 +1941,7 @@ void show_rcu_tasks_trace_gp_kthread(void)
{
char buf[64];
- sprintf(buf, "N%lu h:%lu/%lu/%lu",
+ snprintf(buf, sizeof(buf), "N%lu h:%lu/%lu/%lu",
data_race(n_trc_holdouts),
data_race(n_heavy_reader_ofl_updates),
data_race(n_heavy_reader_updates),
