| Message ID | 20240327163657.606414-1-kiryushin@ancud.ru (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] rcu-tasks: Update show_rcu_tasks_trace_gp_kthread buffer size | expand |
On Wed, 27 Mar 2024 19:36:56 +0300 Nikita Kiryushin <kiryushin@ancud.ru> wrote: > diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h > index 147b5945d67a..963ecae3c8e6 100644 > --- a/kernel/rcu/tasks.h > +++ b/kernel/rcu/tasks.h > @@ -1994,7 +1994,7 @@ void show_rcu_tasks_trace_gp_kthread(void) > { > char buf[64]; > > - sprintf(buf, "N%lu h:%lu/%lu/%lu", > + snprintf(buf, ARRAY_SIZE(buf), "N%lu h:%lu/%lu/%lu", Nit, but I would have used sizeof(buf) instead of ARRAY_SIZE(buf) as that's more common practice for this type of code. [ do a: git grep 'sizeof(buf)' ] -- Steve > data_race(n_trc_holdouts), > data_race(n_heavy_reader_ofl_updates), > data_race(n_heavy_reader_updates),
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index 147b5945d67a..963ecae3c8e6 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -1994,7 +1994,7 @@ void show_rcu_tasks_trace_gp_kthread(void) { char buf[64]; - sprintf(buf, "N%lu h:%lu/%lu/%lu", + snprintf(buf, ARRAY_SIZE(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),
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> --- v2: Use snprintf() as Steven Rostedt <rostedt@goodmis.org> suggested. kernel/rcu/tasks.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)