5.10-stable review patch. If anyone has any objections, please let me know.
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From: Nikita Kiryushin kiryushin@ancud.ru
commit cc5645fddb0ce28492b15520306d092730dffa48 upstream.
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@ancud.ru Reviewed-by: Steven Rostedt (Google) rostedt@goodmis.org Signed-off-by: Paul E. McKenney paulmck@kernel.org Signed-off-by: Uladzislau Rezki (Sony) urezki@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Vamsi Krishna Brahmajosyula vamsi-krishna.brahmajosyula@broadcom.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/rcu/tasks.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -1240,7 +1240,7 @@ static void show_rcu_tasks_trace_gp_kthr { char buf[64];
- sprintf(buf, "N%d h:%lu/%lu/%lu", atomic_read(&trc_n_readers_need_end), + snprintf(buf, sizeof(buf), "N%d h:%lu/%lu/%lu", atomic_read(&trc_n_readers_need_end), data_race(n_heavy_reader_ofl_updates), data_race(n_heavy_reader_updates), data_race(n_heavy_reader_attempts));