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Fri, 1 Nov 2024 16:26:24 +0000 (UTC) Received: from pps.filterd (m0250809.ppops.net [127.0.0.1]) by mx0a-0064b401.pphosted.com (8.18.1.2/8.18.1.2) with ESMTP id 4A18rZut032555; Fri, 1 Nov 2024 08:07:49 -0700 Received: from ala-exchng01.corp.ad.wrs.com (ala-exchng01.wrs.com [147.11.82.252]) by mx0a-0064b401.pphosted.com (PPS) with ESMTPS id 42mew213k8-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT); Fri, 01 Nov 2024 08:07:49 -0700 (PDT) Received: from ala-exchng01.corp.ad.wrs.com (147.11.82.252) by ala-exchng01.corp.ad.wrs.com (147.11.82.252) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.39; Fri, 1 Nov 2024 08:07:48 -0700 Received: from pop-os.wrs.com (172.25.44.6) by ala-exchng01.corp.ad.wrs.com (147.11.82.252) with Microsoft SMTP Server id 15.1.2507.39 via Frontend Transport; Fri, 1 Nov 2024 08:07:47 -0700 From: To: , , CC: , , , , , , , , Subject: [PATCH 1/1: 5.10/5.15] net: bridge: xmit: make sure we have at least eth header len bytes Date: Fri, 1 Nov 2024 11:07:45 -0400 Message-ID: <20241101150745.3671416-2-Randy.MacLeod@windriver.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20241101150745.3671416-1-Randy.MacLeod@windriver.com> References: <20241101150745.3671416-1-Randy.MacLeod@windriver.com> Precedence: bulk X-Mailing-List: bridge@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Proofpoint-GUID: 6_PsvydZLq400R8lmhL0uJb2o0wSTisC X-Authority-Analysis: v=2.4 cv=dLb0m/Zb c=1 sm=1 tr=0 ts=6724eec5 cx=c_pps a=/ZJR302f846pc/tyiSlYyQ==:117 a=/ZJR302f846pc/tyiSlYyQ==:17 a=eMPNgDwjIQXpT8XC:21 a=VlfZXiiP6vEA:10 a=t7CeM3EgAAAA:8 a=hSkVLCK3AAAA:8 a=edf1wS77AAAA:8 a=IJ2IFIBGmV0-FWXsoRQA:9 a=FdTzh2GWekK77mhwV6Dw:22 a=cQPPKAXgyycSBL8etih5:22 a=DcSpbTIhAlouE1Uv7lRv:22 X-Proofpoint-ORIG-GUID: 6_PsvydZLq400R8lmhL0uJb2o0wSTisC X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1051,Hydra:6.0.680,FMLib:17.12.62.30 definitions=2024-11-01_09,2024-11-01_01,2024-09-30_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 malwarescore=0 impostorscore=0 lowpriorityscore=0 spamscore=0 bulkscore=0 adultscore=0 clxscore=1015 priorityscore=1501 mlxscore=0 mlxlogscore=999 suspectscore=0 phishscore=0 classifier=spam authscore=0 adjust=0 reason=mlx scancount=1 engine=8.21.0-2409260000 definitions=main-2411010109 From: Randy MacLeod [ Upstream commit 8bd67ebb50c0145fd2ca8681ab65eb7e8cde1afc ] Based on above commit but simplified since pskb_may_pull_reason() does not exist until 6.1. syzbot triggered an uninit value[1] error in bridge device's xmit path by sending a short (less than ETH_HLEN bytes) skb. To fix it check if we can actually pull that amount instead of assuming. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Reported-by: syzbot+a63a1f6a062033cf0f40@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=a63a1f6a062033cf0f40 Signed-off-by: Randy MacLeod --- net/bridge/br_device.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c index d3ea9d0779fb..84e37108c6b5 100644 --- a/net/bridge/br_device.c +++ b/net/bridge/br_device.c @@ -36,6 +36,11 @@ netdev_tx_t br_dev_xmit(struct sk_buff *skb, struct net_device *dev) const unsigned char *dest; u16 vid = 0; + if (unlikely(!pskb_may_pull(skb, ETH_HLEN))) { + kfree_skb(skb); + return NETDEV_TX_OK; + } + memset(skb->cb, 0, sizeof(struct br_input_skb_cb)); rcu_read_lock(); -- 2.34.1