From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 219073ACEFE; Mon, 17 Aug 2026 14:47:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786978043; cv=none; b=iFXd6azJNSftcPwk7SZiHTdXvLAGAbUUXTEtPdQ7aTSJkzTzsVb5wmRJVp6ULT6NLWxuROyowCZDS4XXwWY9vtdFt9glOGd3xiFGgGYb4aP6ygvr3Zz446Ufik8mIjXN4oEXvSyb5z/H+VdS+4JZfJ4Dmq+N3L4aLYeZKy2QYBY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786978043; c=relaxed/simple; bh=2ajiivdCCLv1FzznFXuf3+xxN16dUZPsZCbhofIEutI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=TdrTQGs3H5Q/72m4KyY+jkWULiW+hDm23fPFh44smxwDcigbecEefYBwveyS3BHgT2m3hOJbYlZA6GXGEWCGJlUBrxgmZtZ9lYjnGPEAHTc7f4mfYKzIaqV41LbSPWzyZunChZ5/CbGXZaemzbawdCRL8uW23Osiq73Rxv4i+1E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ZywwTL5W; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="ZywwTL5W" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8062E1F000E9; Mon, 17 Aug 2026 14:47:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786978042; bh=em/RqDuETmlRTWSNHyRyaZCoWDJmkRk8inJ9xRSR4QM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ZywwTL5WholteKCcrKSpAwwPR7RhcnU4uulb7D76dOJMpFluJOxnNin3mOUxd9yxa YqY3Kgji7+8+OA1vnIAhJYiWoMoV0AZVcGSxiXXKbsdUdapc3ZBnC5TZBnF6mkVgVb iuf7ekHUdzxU/8AHMUIqmnC1KdmitLOXPW2t7c38= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, AutonomousCodeSecurity@microsoft.com, Eelco Chaudron , "Cen Zhang (Microsoft)" , Ilya Maximets , Paolo Abeni , Sasha Levin Subject: [PATCH 6.12 042/181] net/openvswitch: check Ethernet header length in key_extract() Date: Mon, 17 Aug 2026 15:32:16 +0200 Message-ID: <20260817132537.050195537@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260817132535.394764707@linuxfoundation.org> References: <20260817132535.394764707@linuxfoundation.org> User-Agent: quilt/0.69 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 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Cen Zhang (Microsoft) [ Upstream commit cf6f8b29befb92173659bcef6a441d274947bfae ] 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 calling check_header() in key_extract() before accessing the Ethernet header. Fixes: 217ac77a3c25 ("openvswitch: allow L3 netdev ports") Reported-by: AutonomousCodeSecurity@microsoft.com Reviewed-by: Eelco Chaudron Signed-off-by: Cen Zhang (Microsoft) Reviewed-by: Ilya Maximets Link: https://patch.msgid.link/20260730222006.118652-1-blbllhy@gmail.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin --- net/openvswitch/flow.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/net/openvswitch/flow.c b/net/openvswitch/flow.c index b80bd3a907739..52e261ce91e8e 100644 --- a/net/openvswitch/flow.c +++ b/net/openvswitch/flow.c @@ -893,8 +893,6 @@ static int key_extract_l3l4(struct sk_buff *skb, struct sw_flow_key *key) * Ethernet header * @key: output flow key * - * The caller must ensure that skb->len >= ETH_HLEN. - * * Initializes @skb header fields as follows: * * - skb->mac_header: the L2 header. @@ -914,8 +912,6 @@ static int key_extract_l3l4(struct sk_buff *skb, struct sw_flow_key *key) */ static int key_extract(struct sk_buff *skb, struct sw_flow_key *key) { - struct ethhdr *eth; - /* Flags are always used as part of stats */ key->tp.flags = 0; @@ -930,6 +926,13 @@ static int key_extract(struct sk_buff *skb, struct sw_flow_key *key) skb_reset_network_header(skb); key->eth.type = skb->protocol; } else { + struct ethhdr *eth; + int err; + + err = check_header(skb, ETH_HLEN); + if (unlikely(err)) + return err; + 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