From: "Paul E. McKenney" <paulmck@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Nikita Kiryushin <kiryushin@ancud.ru>,
Frederic Weisbecker <frederic@kernel.org>,
Neeraj Upadhyay <quic_neeraju@quicinc.com>,
Joel Fernandes <joel@joelfernandes.org>,
Josh Triplett <josh@joshtriplett.org>,
Boqun Feng <boqun.feng@gmail.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Zqiang <qiang.zhang1211@gmail.com>,
rcu@vger.kernel.org, linux-kernel@vger.kernel.org,
lvc-project@linuxtesting.org
Subject: Re: [PATCH v4] rcu-tasks: Fix show_rcu_tasks_trace_gp_kthread buffer overflow
Date: Wed, 27 Mar 2024 11:31:01 -0700 [thread overview]
Message-ID: <608b2ed9-a7fa-482d-b1e5-e5c2ad5849c7@paulmck-laptop> (raw)
In-Reply-To: <20240327135246.54cdb58e@gandalf.local.home>
On Wed, Mar 27, 2024 at 01:52:46PM -0400, Steven Rostedt wrote:
> 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>
Queued and pushed, thank you both!
Thanx, Paul
> -- 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),
>
prev parent reply other threads:[~2024-03-27 18:31 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-26 17:48 [PATCH] rcu-tasks: Update show_rcu_tasks_trace_gp_kthread buffer size Nikita Kiryushin
2024-03-26 18:06 ` Paul E. McKenney
2024-03-26 19:22 ` Steven Rostedt
2024-03-26 19:55 ` Nikita Kiryushin
2024-03-26 20:28 ` Steven Rostedt
2024-03-27 16:36 ` [PATCH v2] " Nikita Kiryushin
2024-03-27 16:46 ` [PATCH v3] rcu-tasks: Fix show_rcu_tasks_trace_gp_kthread buffer overflow Nikita Kiryushin
2024-03-27 16:51 ` [PATCH v2] rcu-tasks: Update show_rcu_tasks_trace_gp_kthread buffer size Steven Rostedt
2024-03-27 17:47 ` [PATCH v4] rcu-tasks: Fix show_rcu_tasks_trace_gp_kthread buffer overflow Nikita Kiryushin
2024-03-27 17:52 ` Steven Rostedt
2024-03-27 18:31 ` Paul E. McKenney [this message]
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