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 4AC3F18B487; Tue, 10 Sep 2024 10:00:16 +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=1725962416; cv=none; b=F/dfetLB+4SZs+whF6oEU2iFK7yemZpJv79gg3im6W7ck/azJrO2rJIGch7XH+WBOQieBB6ko2s6GdeK68n6RLYmn/DKbyCXglZdEWCa+pIWUKtjk5g9/5oGoT5pp1jTBIp+8+knhKUhX34EEujvlC5Ni1iQ1DPiNh+GzcM5by0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725962416; c=relaxed/simple; bh=CnuRlBRCoi6uZb8bN95LoX6ZUy/sXy1AN0OwQYu2EaE=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=K45oz4J2uLQsJU93NI4ZzhoVTQOtVyH36V7A+po5kSlcLRiHCihKhAF/iK+J1vYLAegHmRoXu0rkiD1qjgAcx1APyQbKMaUvAQHDFvhhJg3aeIu9F8h90wXpEcO5Wd2Jd6mHnthuDkiSnIZlHqAQNQGdOwWbtmEOUBhs9Wghb/4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=fgWynHYJ; 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="fgWynHYJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C921AC4CEC3; Tue, 10 Sep 2024 10:00:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1725962416; bh=CnuRlBRCoi6uZb8bN95LoX6ZUy/sXy1AN0OwQYu2EaE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fgWynHYJ4wHhqh65SoR06kjjD5xaBRsebvwmJrpnZi6r/dGjR6UBKp7esP2xzJ/i3 oJnTqGdcU1mA5SXgns1dLKw6ap99aVdn8023c+SHFLVGTMB+fQzk8dRsdeEHZwJjwZ eW7IHJ0AKI7P9DdYpgZ01s0X3MdQCH7Q1TabWNG0= 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 5.4 026/121] sch/netem: fix use after free in netem_dequeue Date: Tue, 10 Sep 2024 11:31:41 +0200 Message-ID: <20240910092546.959113816@linuxfoundation.org> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240910092545.737864202@linuxfoundation.org> References: <20240910092545.737864202@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 5.4-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 @@ -733,11 +733,10 @@ 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; }