From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 168391EC01C; Wed, 6 Nov 2024 13:15:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730898956; cv=none; b=G4Jv0Qwc3osnurEukTYsik2rjJhTIBlDOqHNhP066JY+XhaL6on4iUuOk6Kv+uJr4KY4ZjdCmSs6Atfio9cXv3Q+DIeCJz/vTSlt6JPiX32Ny0yfVV0o3Cu5pihOCR5cgK43o2wrX8ozwwMLuJxG2Usa+dCpK6eaG9aTEfVebsk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730898956; c=relaxed/simple; bh=9EEgOGkd5a+8JSlNbpO5/upguQvr8/DrH9GWzvYIDk4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Dr93iLgHYw4UX7hr9vYPDg7vLt879VvuscMqUqcZ6gjaihctBngdJbU8m513r9eGpcr75YHTzPUyp8pr+sRWSmKFjFJmj+DUIB7EovGIQEJAFS5TyGjV6BKy9RjVvsv7pM4+kRRTVelcTLRwWKoK4bkGAvqMXJePb1XZA+HTJ24= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=T0Kjzg54; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="T0Kjzg54" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8F430C4CECD; Wed, 6 Nov 2024 13:15:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1730898956; bh=9EEgOGkd5a+8JSlNbpO5/upguQvr8/DrH9GWzvYIDk4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=T0Kjzg546J+gvsDVdBDnJ0mYNLcxy8H1rTaiFCavMdasEITzt9YUdveivzWfFkKeG JJPFzzp6jv+2veJ1DOIL8GJRXOtv1Ka5+o1f6Ib9tSRHES0LQ3N4I+MXPMZxd2/oqG NSeXsxZFUts+BGp5TgyVDziv5UKeekBL4aCSB0bs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+b65e0af58423fc8a73aa@syzkaller.appspotmail.com, Vinicius Costa Gomes , Dmitry Antipov , Paolo Abeni , Sasha Levin Subject: [PATCH 5.4 412/462] net: sched: fix use-after-free in taprio_change() Date: Wed, 6 Nov 2024 13:05:05 +0100 Message-ID: <20241106120341.696425950@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241106120331.497003148@linuxfoundation.org> References: <20241106120331.497003148@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dmitry Antipov [ Upstream commit f504465970aebb2467da548f7c1efbbf36d0f44b ] In 'taprio_change()', 'admin' pointer may become dangling due to sched switch / removal caused by 'advance_sched()', and critical section protected by 'q->current_entry_lock' is too small to prevent from such a scenario (which causes use-after-free detected by KASAN). Fix this by prefer 'rcu_replace_pointer()' over 'rcu_assign_pointer()' to update 'admin' immediately before an attempt to schedule freeing. Fixes: a3d43c0d56f1 ("taprio: Add support adding an admin schedule") Reported-by: syzbot+b65e0af58423fc8a73aa@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=b65e0af58423fc8a73aa Acked-by: Vinicius Costa Gomes Signed-off-by: Dmitry Antipov Link: https://patch.msgid.link/20241018051339.418890-1-dmantipov@yandex.ru Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- net/sched/sch_taprio.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c index b8e26013bd75f..8fccb30e3ee9b 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -1591,7 +1591,8 @@ static int taprio_change(struct Qdisc *sch, struct nlattr *opt, taprio_start_sched(sch, start, new_admin); - rcu_assign_pointer(q->admin_sched, new_admin); + admin = rcu_replace_pointer(q->admin_sched, new_admin, + lockdep_rtnl_is_held()); if (admin) call_rcu(&admin->rcu, taprio_free_sched_cb); -- 2.43.0