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 7E80E46444; Tue, 10 Sep 2024 09:36:35 +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=1725960995; cv=none; b=K9qbKmdChqzJ6VZ8vecksg/Z2mLr3nVxgb+TeHmKGRs7K0NczJa7JzMPUCsraPNmcxLhdoGRkXccWxN12ilVkmfVc0SBYnBtQQxOFvKDOWCqiaU1E7Y8j2ZOyb98KBTIte82T8hPZwtAyPQZyjv/iEAr5ki1RobC5lmFe2gf6ks= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725960995; c=relaxed/simple; bh=Yv8HcB3EjvNfplCUD5tlIAk79yp9CaoVdK5l3/5nMFc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=gpAUcqSgGyL+hm20Y0z94lgNFIy4awxSqEe3nze77BUlfX+ESHk14bXa3i8E8P2g+JE+tsWIx0cFX8pQbB7feIN6Kkxb+z4MtgPAcZDHHttfwZbv6Zp6bS9rpaYEOW666h1leJvH48HJbSyqJ36Zezm2vbix5dX7o0NT98CHfVk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=u2JCgw5b; 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="u2JCgw5b" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B12B2C4CEC3; Tue, 10 Sep 2024 09:36:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1725960995; bh=Yv8HcB3EjvNfplCUD5tlIAk79yp9CaoVdK5l3/5nMFc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=u2JCgw5b1yExiIjbaboCRTTB2FIdjeTYDfqVOcL540ZymG2Ui9OchMOnXlwUZtdPE Nf0avDGOoqDgAHlT0oC4AoEWrBGaNXFy9HramsM4OtNhf9FmAgGBM6trJQhGsNB/nn HA1Y2CYdGTPwSGaUkKHJdXeirNVHNUc6v646WUMc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Budimir Markovic , Stephen Hemminger , Jakub Kicinski Subject: [PATCH 4.19 18/96] sch/netem: fix use after free in netem_dequeue Date: Tue, 10 Sep 2024 11:31:20 +0200 Message-ID: <20240910092542.222308070@linuxfoundation.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240910092541.383432924@linuxfoundation.org> References: <20240910092541.383432924@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 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Stephen Hemminger commit 3b3a2a9c6349e25a025d2330f479bc33a6ccb54a upstream. If netem_dequeue() enqueues packet to inner qdisc and that qdisc returns __NET_XMIT_STOLEN. The packet is dropped but qdisc_tree_reduce_backlog() is not called to update the parent's q.qlen, leading to the similar use-after-free as Commit e04991a48dbaf382 ("netem: fix return value if duplicate enqueue fails") Commands to trigger KASAN UaF: ip link add type dummy ip link set lo up ip link set dummy0 up tc qdisc add dev lo parent root handle 1: drr tc filter add dev lo parent 1: basic classid 1:1 tc class add dev lo classid 1:1 drr tc qdisc add dev lo parent 1:1 handle 2: netem tc qdisc add dev lo parent 2: handle 3: drr tc filter add dev lo parent 3: basic classid 3:1 action mirred egress redirect dev dummy0 tc class add dev lo classid 3:1 drr ping -c1 -W0.01 localhost # Trigger bug tc class del dev lo classid 1:1 tc class add dev lo classid 1:1 drr ping -c1 -W0.01 localhost # UaF Fixes: 50612537e9ab ("netem: fix classful handling") Reported-by: Budimir Markovic Signed-off-by: Stephen Hemminger Link: https://patch.msgid.link/20240901182438.4992-1-stephen@networkplumber.org Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- net/sched/sch_netem.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) --- a/net/sched/sch_netem.c +++ b/net/sched/sch_netem.c @@ -697,11 +697,10 @@ deliver: err = qdisc_enqueue(skb, q->qdisc, &to_free); kfree_skb_list(to_free); - if (err != NET_XMIT_SUCCESS && - net_xmit_drop_count(err)) { - qdisc_qstats_drop(sch); - qdisc_tree_reduce_backlog(sch, 1, - pkt_len); + if (err != NET_XMIT_SUCCESS) { + if (net_xmit_drop_count(err)) + qdisc_qstats_drop(sch); + qdisc_tree_reduce_backlog(sch, 1, pkt_len); } goto tfifo_dequeue; }