From patchwork Wed Aug 7 10:39:41 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Antipov X-Patchwork-Id: 13756138 X-Patchwork-Delegate: kuba@kernel.org Received: from forward201a.mail.yandex.net (forward201a.mail.yandex.net [178.154.239.92]) (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 794C81C8FBB for ; Wed, 7 Aug 2024 10:47:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=178.154.239.92 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723027668; cv=none; b=d36QeBqmtuk7bJ14rGo/yeJTFO0swWH48DkT9nzH8MI75ipPLh/5GOKmwRm85QbIfAqRTUC7q2NXZTw725nRTFAHI4oskaxZScPF8P7lf/Rhscw/s/dZt4vcBvRuu2ETykImudV22/VHihNBldBFLiesI06K9HnR06ToGVgQpYs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723027668; c=relaxed/simple; bh=r/xcw4mkfLvHrB7PfXQuHyAeZI0Y0vdAmcw8mBFA1B8=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=uWg520K4mkAze/2LrihMOLtJWRrM+NUPKt/3Og83FKjcFdbAAkSllPbC5yrteqNx0wCNaSxH+JdZPHPxTX9wq8Voc0eEu69j/xzEjiMzjA3pvyE92/C70WGM34ufduO6JcAQBecOBG7MKZ/P5hjXmO7K1ZQBamwo80waaEVqfoQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=yandex.ru; spf=pass smtp.mailfrom=yandex.ru; dkim=pass (1024-bit key) header.d=yandex.ru header.i=@yandex.ru header.b=ncrkBtjV; arc=none smtp.client-ip=178.154.239.92 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=yandex.ru Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=yandex.ru Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=yandex.ru header.i=@yandex.ru header.b="ncrkBtjV" Received: from forward101a.mail.yandex.net (forward101a.mail.yandex.net [IPv6:2a02:6b8:c0e:500:1:45:d181:d101]) by forward201a.mail.yandex.net (Yandex) with ESMTPS id D063D62A0C for ; Wed, 7 Aug 2024 13:40:41 +0300 (MSK) Received: from mail-nwsmtp-smtp-production-main-31.vla.yp-c.yandex.net (mail-nwsmtp-smtp-production-main-31.vla.yp-c.yandex.net [IPv6:2a02:6b8:c0f:26bf:0:640:efa0:0]) by forward101a.mail.yandex.net (Yandex) with ESMTPS id D747B60AC0; Wed, 7 Aug 2024 13:40:33 +0300 (MSK) Received: by mail-nwsmtp-smtp-production-main-31.vla.yp-c.yandex.net (smtp/Yandex) with ESMTPSA id WeaXEH6Sl4Y0-cbPFdGVk; Wed, 07 Aug 2024 13:40:33 +0300 X-Yandex-Fwd: 1 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex.ru; s=mail; t=1723027233; bh=AF4nlcPDOOqSXjDCWCvo6NX6QZUE6FVV55e/YuwK8Nc=; h=Message-ID:Date:Cc:Subject:To:From; b=ncrkBtjVMJXCbjh+BUwlWyWRhOcWTs+lcZp1tvOZEEowqW21KoavQ8PV/eldyGLic l16MzOHM0Web8nVnGOYuS5/sSMifqHFWoRNG26T56SpcZz0JlfRSwpk/clkrJTgOS7 GUPrDC+KUdiEORtWeEBhjE49m3TC5WZxsg038FmQ= Authentication-Results: mail-nwsmtp-smtp-production-main-31.vla.yp-c.yandex.net; dkim=pass header.i=@yandex.ru From: Dmitry Antipov To: Vinicius Costa Gomes Cc: Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org, lvc-project@linuxtesting.org, Dmitry Antipov , syzbot+b65e0af58423fc8a73aa@syzkaller.appspotmail.com Subject: [PATCH 1/3] net: sched: fix use-after-free in taprio_change() Date: Wed, 7 Aug 2024 13:39:41 +0300 Message-ID: <20240807103943.1633950-1-dmantipov@yandex.ru> X-Mailer: git-send-email 2.45.2 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org 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 Signed-off-by: Dmitry Antipov --- 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 cc2df9f8c14a..59fad74d5ff9 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -1963,7 +1963,8 @@ 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);