From af7b560c88fb420099e29890aa682b8a3efc8784 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 b24ef77325ee..0e50ec9ded86 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -1323,7 +1323,7 @@ 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));