From: Nikita Kiryushin kiryushin@ancud.ru

mainline inclusion from mainline-v6.10-rc1 commit cc5645fddb0ce28492b15520306d092730dffa48 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IA6SGB CVE: CVE-2024-38577

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

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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 Conflicts: kernel/rcu/tasks.h [yyl: adjust context] Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- 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 c5624ab0580c..25d636c39efc 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -1238,7 +1238,7 @@ 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));