From 5efd52730f2a921244856d43bdda3a347a013c1d Mon Sep 17 00:00:00 2001 From: Nikita Kiryushin Date: Wed, 27 Mar 2024 20:47:47 +0300 Subject: [PATCH] rcu-tasks: Fix show_rcu_tasks_trace_gp_kthread buffer overflow 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 Reviewed-by: Steven Rostedt (Google) Signed-off-by: Paul E. McKenney Signed-off-by: Uladzislau Rezki (Sony) Signed-off-by: Sasha Levin Signed-off-by: Vamsi Krishna Brahmajosyula Signed-off-by: Greg Kroah-Hartman --- kernel/rcu/tasks.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index 71f0edbc0..b362be259 100755 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -1240,7 +1240,7 @@ static void show_rcu_tasks_trace_gp_kthread(void) { 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));