Messages in this thread | | | Date | Wed, 27 Mar 2024 13:52:46 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH v4] rcu-tasks: Fix show_rcu_tasks_trace_gp_kthread buffer overflow |
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On Wed, 27 Mar 2024 20:47:47 +0300 Nikita Kiryushin <kiryushin@ancud.ru> wrote:
> 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(). >
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
-- Steve
> 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> > --- > v4: Change ARRAY_SIZE to sizeof() as more idiomatic > as Steven Rostedt <rostedt@goodmis.org> suggested > v3: Fixed commit message > v2: Use snprintf() as > Steven Rostedt <rostedt@goodmis.org> suggested. > 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 147b5945d67a..2a453de9f3d9 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, sizeof(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),
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