From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yw1-f171.google.com (mail-yw1-f171.google.com [209.85.128.171]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8C5D9379C39 for ; Thu, 23 Jul 2026 04:23:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.128.171 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784780613; cv=none; b=iSaNZ8QKfHFlneQLVrqvvvHQpWTK3qs329oYoneYiDCxCTeFKhAPmhcd5EeGfJbF+9bg03Wr4flsPWu0E5hjETh2bGeIpKLHCnvCtXFYs+SOOyw9/aPabg3TkYMtITSFPOGXYDYt+AG1ByyLxvHZQbARbq2KdosOhH7/tMtwxDY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784780613; c=relaxed/simple; bh=aa5JpoxyiiIszoUJIXjj6mrtfIfrRBPmusHtb58OjJg=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=jp2Ps3CQvqkDNf9lsAibNdNAAm2dzemHMTXS9+cElevN3LR66yq9GbCWfrwVNHEqAWqu1fd7drImgyb8WpJvseqkKsidBq56LhmKTYjD6I1S3xTv5OmojRp+NxEvXDQssndUmBLXrC9uAIpYERzG5hhSEea14/bnOgsPVSyCAbo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=A4np3G9f; arc=none smtp.client-ip=209.85.128.171 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="A4np3G9f" Received: by mail-yw1-f171.google.com with SMTP id 00721157ae682-8143daf89c7so2041787b3.1 for ; Wed, 22 Jul 2026 21:23:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1784780587; x=1785385387; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to:content-type; bh=0Iu9ZA5UsRHXZ0k9a3suZoz0cbH3TgLB+kgHy6PNqKU=; b=A4np3G9fx57IlwJCUo9oEadiZzsuZ9+aO5yC+281EV5MECkdkBR/7/8XJrv5J/zAxb 2OhA3+w07YFtfg3dF2FDPnQ+eXkb27PzV7cOxBuBmUedEAYBMCJPEJrvh/yWCGoIzDL1 ZieIMdvpnwdU2cUNds68H3tpEx8HmiXL3cqOxlLtWLz1JN3N7svXjk9ZJsoUdDVGVGHv n4Ub0DBqSEubG3SYvg0OqSlgCA36SLJiUolVRHAhbIVb59z75Bw+9J0z9VwROM/Qdpd0 46QSJ+rmSMrDxvqu0z+0RDokAXrSDTf6DvWL1i1ONs/5Asf8QwTYK99s6WRk31vONKGn UUbA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1784780587; x=1785385387; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=0Iu9ZA5UsRHXZ0k9a3suZoz0cbH3TgLB+kgHy6PNqKU=; b=pZK3z3oxz2uGE44qwJkFvmbFVtfNWBzg77LvBeyqBI1qEf2UIDjr6+NTzvKwxRuW0D CetEdbgqvNLqIG8Es42/3nSy52knkdgD4YFMU/ghEQvXXe/9+AV3D9fmHiWE4fvIuFJt G+GXRn7FFMTfAMJFpm59tULiCGRQNf7npevZeP+BdtJAz1pepi1EJ+9vd2SmZt728ItO 1IzvV0gugEauM6LrgAc1dAsw+RDxYL45rujyUkN9aYB4boeLj6J/4fujqChELzBHTWIk nL7+QaXVrpNI0IcjoPvTTN9fNkRcWJ67/2gRJa8XHFdNGYXZZQMandNdlmsg2b+riz+Z 67QA== X-Gm-Message-State: AOJu0YxyZGKjE6SK/B0rJhe3uEb05gDSzd2XeMOwH0eTMyJZxGGWmYaX bw9C74HmzeM/ZJQY+s4sDwv13pkSV44HlEMAf16yVQctQ3gvzweugYJk X-Gm-Gg: AR+sD13eNMOa9UYlRUYVOYWQRWkUMi0pHxIHqDybkkMQBaf83mwx8pHYmL1KKQanV0P u7qVhocaP9qMBrg+6jHqaHca8gKeXjR1EGFcXNjvt+dpVGVp3w7ksOU5c+pnt0Si4YgMNQz8X4a bRKOsfvK1kmbpCOMfkk7UWrHrbWKX2Wc9Z3uR1DphWhHwU7aq1rnAYLQzZlBF5DYfIT59g2e6Tv c/kqLBCiw5c142JwQStjlrRA1hHzLxY0OBgJppVMZA37NaUmv4YBUoejKMIx4/XjMf9YHtEW363 K5gw2kQ55DUkibBcCUeIGE4UqlijntRxaK/V4f8rTVwbjv+PUNv1Xltvvr45LLvE4HemUsCgNZE v4ONOSl0FGWPwPRDvnXyFMbSERbhmogjIl8IgnBcz13nrL62vV/XlL+wS7Zj0qh9JDfyFXroj+H yxpRTxGcxnyFWyJh1ZmuZ6qb/a6AWlb+K0p12EqyM0eLBaRR3d0eAnKPpiqM4fhvzo58Ku05b1g W+LDPFxefzQJg== X-Received: by 2002:a05:690c:6c87:b0:81c:fc30:a35c with SMTP id 00721157ae682-81f4c281ce8mr4429137b3.42.1784780586767; Wed, 22 Jul 2026 21:23:06 -0700 (PDT) Received: from LAPTOP-83ECOPAB.f7a5e5c3-cab1-4810-bdbb-207cdd06de9e.globalsecureaccess.local ([136.55.173.105]) by smtp.gmail.com with ESMTPSA id 00721157ae682-81f33da4122sm23388037b3.32.2026.07.22.21.23.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 22 Jul 2026 21:23:06 -0700 (PDT) From: "Cen Zhang (Microsoft)" To: aconole@redhat.com, echaudro@redhat.com, i.maximets@ovn.org, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org Cc: netdev@vger.kernel.org, dev@openvswitch.org, linux-kernel@vger.kernel.org, AutonomousCodeSecurity@microsoft.com, tgopinath@linux.microsoft.com, kys@microsoft.com, blbllhy@gmail.com Subject: [PATCH v2] net/openvswitch: check Ethernet header length before key_extract() Date: Thu, 23 Jul 2026 00:23:04 -0400 Message-ID: <20260723042304.88332-1-blbllhy@gmail.com> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When a packet arrives on an ARPHRD_NONE device (e.g. TUN), ovs_flow_key_extract() trusts the user-provided skb->protocol field: if it is ETH_P_TEB, the packet is classified as MAC_PROTO_ETHERNET and key_extract() is called without ensuring the skb has ETH_HLEN (14) bytes of linear data. key_extract() unconditionally pulls 2 * ETH_ALEN bytes for MAC addresses and parse_ethertype() pulls 2 more, either of which triggers a kernel BUG in __skb_pull() when the linear area is too small. kernel BUG at include/linux/skbuff.h:2848! RIP: 0010:key_extract+0xa7e/0xd90 net/openvswitch/flow.c:933 ovs_flow_key_extract+0x419/0xa70 ovs_vport_receive+0x222/0x390 netdev_frame_hook+0x3e0/0x630 tun_get_user+0x2d0c/0x38e0 Fixed by adding checks in key_extract() before pulling the Ethernet header. Fixes: 217ac77a3c25 ("openvswitch: allow L3 netdev ports") Reported-by: AutonomousCodeSecurity@microsoft.com Link: https://lore.kernel.org/all/20260721143602.64677-1-blbllhy@gmail.com Signed-off-by: Cen Zhang (Microsoft) --- v2: Moved the check into key_extract() per Ilya Maximets. net/openvswitch/flow.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/openvswitch/flow.c b/net/openvswitch/flow.c index 66366982f604..de7b77d6702a 100644 --- a/net/openvswitch/flow.c +++ b/net/openvswitch/flow.c @@ -926,6 +926,9 @@ static int key_extract(struct sk_buff *skb, struct sw_flow_key *key) skb_reset_network_header(skb); key->eth.type = skb->protocol; } else { + if (unlikely(!pskb_may_pull(skb, ETH_HLEN))) + return -EINVAL; + eth = eth_hdr(skb); ether_addr_copy(key->eth.src, eth->h_source); ether_addr_copy(key->eth.dst, eth->h_dest); -- 2.53.0