From patchwork Wed Sep 4 12:08:41 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Antipov X-Patchwork-Id: 13790702 X-Patchwork-Delegate: kuba@kernel.org Received: from forward101b.mail.yandex.net (forward101b.mail.yandex.net [178.154.239.148]) (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 3941F1D88AF for ; Wed, 4 Sep 2024 12:08:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=178.154.239.148 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725451730; cv=none; b=ZbLOWHUMcHPDhftnAoQTP80NVH3rxaMXo3IyWZSnawzHecHS74lGsgh//Oyu9T0OfTZbpV4vh30Yv/3OjpWUaL846c4YX5M/WZKYFjrtRz3oMYxUmB24k7vQybs/jXWnhW1f9SdDLpNR5JCvBoA8oV8nj99T3KH2xr5/PUcDPZE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725451730; c=relaxed/simple; bh=tudkOBqicCQK4Gxw3wenulSEBK/j0ZtQ4l2gzrY7VeI=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=FsaEQxu4eU4ndHEVgOZLjWkbS0/9hn4dGUVUKsyMiqWFdeysHaAM5zwDcM7EV0t90XEsnAbN6UYTk2xG78hI3Yd5c1cHyHVf4esxP/oQdyEEM7RYazACcwS1ZV24MVeFOy7Ptx6PVNh0gDHYPGI4udGQS6VvVNW7EWpJMR4IHxc= 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=dD/qhVFq; arc=none smtp.client-ip=178.154.239.148 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="dD/qhVFq" Received: from mail-nwsmtp-smtp-production-main-39.sas.yp-c.yandex.net (mail-nwsmtp-smtp-production-main-39.sas.yp-c.yandex.net [IPv6:2a02:6b8:c08:f220:0:640:b85:0]) by forward101b.mail.yandex.net (Yandex) with ESMTPS id 336A560B4A; Wed, 4 Sep 2024 15:08:45 +0300 (MSK) Received: by mail-nwsmtp-smtp-production-main-39.sas.yp-c.yandex.net (smtp/Yandex) with ESMTPSA id h8b9pL7j6Os0-OqhS6W8E; Wed, 04 Sep 2024 15:08:44 +0300 X-Yandex-Fwd: 1 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex.ru; s=mail; t=1725451724; bh=zAt49LMWuIYAsshcBExvuI4BWZoXaEJfzbSelIL521w=; h=Message-ID:Date:Cc:Subject:To:From; b=dD/qhVFq2XsHNoIO2EbOWIZ3z1lJcgwroDh4v/bTNbmKlETnjBseCWc2UDtNEeWT3 DbcD++97Aywmr247PV8HLB+NnUm4obH6QqceKvU6Hec7n+u/4e8ZqjCH4nHjRRDsZU G9eaCADQuzGOi32mTtWUIHdabUeE6fTOjagiA4fo= Authentication-Results: mail-nwsmtp-smtp-production-main-39.sas.yp-c.yandex.net; dkim=pass header.i=@yandex.ru From: Dmitry Antipov To: Vinicius Costa Gomes Cc: Jakub Kicinski , Paolo Abeni , Simon Horman , netdev@vger.kernel.org, lvc-project@linuxtesting.org, Dmitry Antipov , syzbot+b65e0af58423fc8a73aa@syzkaller.appspotmail.com Subject: [PATCH net v5 1/2] net: sched: fix use-after-free in taprio_change() Date: Wed, 4 Sep 2024 15:08:41 +0300 Message-ID: <20240904120842.3426084-1-dmantipov@yandex.ru> X-Mailer: git-send-email 2.46.0 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 Acked-by: Vinicius Costa Gomes --- v5: unchanged since v4 but resend due to series change v4: adjust subject to target net tree v3: unchanged since v2 v2: unchanged since v1 --- 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);