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 365F1152E1C; Mon, 28 Oct 2024 06:29:21 +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=1730096961; cv=none; b=Yb4Y93npu/yWAzlJTh+O1fTj6qbD4lybtsmTprwLaahtBRccKAo/Qcoc+LRJcqP1TH/IZGQqEIAmeP9/DQg71MdhUCPwKL44jZfdgsiNAHl5k9b66Naf1LmYz0My1wXKh2ulBxIX6b5745ZSkQEJaPP5mtYGrMk0QjCqYbOj6y4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730096961; c=relaxed/simple; bh=pPRQFskTPW0E9aw6B8L9C6fUqh3NNOSUVoBoWozdf9Y=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=VjG39jCNvPy8SA1QN6uOHS9X2W8PCK6Pss9JLnL48b+C3wwQtmJ/Nl8VBKVZndkKKLjjUdQQQZwBJLD7ukLt/vQxTrqtgCH5CPa5LOnUe9gEE3TunkwnVki2/lG3aqXsDs6HnCVknxFZeZpYcHCv9Sd0LAd9nMDExlN+1Vt48h4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=nkmf6wLH; 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="nkmf6wLH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CADC2C4CEC3; Mon, 28 Oct 2024 06:29:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1730096961; bh=pPRQFskTPW0E9aw6B8L9C6fUqh3NNOSUVoBoWozdf9Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=nkmf6wLHFpuAsYx57KcdY4uJ6yOpDG6w752GIyjfYKzoP2WkSVlz4oPFLX8U0K4y9 Xm5bCLefRH8njYosWNa6mJzi1edE6fgsE7fGJUFltQKvlAi4uBMSByWpPPZl2sZ3ED jG+8ST4CTfYP1v4yWzUpG23GYlfQdgoKmHcPXyWg= 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 5.15 61/80] net: sched: fix use-after-free in taprio_change() Date: Mon, 28 Oct 2024 07:25:41 +0100 Message-ID: <20241028062254.310783307@linuxfoundation.org> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241028062252.611837461@linuxfoundation.org> References: <20241028062252.611837461@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-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 49831bd6a37d5..44b971ef343ce 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -1612,7 +1612,8 @@ 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