From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=pass header.oldest-pass=0 smtp.remote-ip=185.203.200.13 ARC-Seal: i=2; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=pass; t=1792429730; b=hIvfSoYZwNsrMnjtDAkMAhNdkFwzAPIaeX9ij5nakOGmcwVjyer9tkO9+eF3k5V9sAik GZ/T+b2TPoDIQiejdwpv8zKWdiqISGbEq1q9rB7DqiZih0SBYeUqRK8Z+tuF5+RuFuLT4 QS9Gx5nXks59HcoLl/fNyf6w4KVi23PYFqVBvNb5RHMtGm9EiVKTqxfwTkIcmTJa580nI XaewEhLSLdnzxzOUDUQa903xB3FDbjQYBUyFisqJPRhKSMSO/SHR2SSp29TJHDjcD6dwC hUx8y5HbZVzD+JGW0BZgXOBIG5cH/52icIU9Cfn2dvduMWtVk/uYVeAGokZcfRYcGxQ== ARC-Message-Signature: i=2; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792429730; h=DMARC-Filter:Received:DKIM-Signature:Received:Received:From:To:Cc: Subject:Date:Message-ID:X-Mailer:In-Reply-To:References:MIME-Version: Content-Transfer-Encoding; bh=zrvCeDlbEo1dcdadZUxg0hKYtY32Q9aSGECGIN22EA4=; b=G2eHiW8/xXlHDnYVeLuZel9c5xPV4wJIhP+xt5fvgwySBT/Xteeo7IrC90GKEns4ZpOQ MPv6dek1jdQCj1fk/Ls4j66lUSqMiShZZBgR5NtzAYQRWwA1ETwYVwiJeowlt7Ev1230M 1ycS372Z2jAlPBrKPxKqqxNvhNCLUigrKhqZUYZrMg2CjYD/srPDLQdQuyp9gxGc+V9Eh 6OdWFLNJzk8fYBgYygxQTwhbvuz9C7h7VoA0/BILE2xEKy3LWljdsTqxosZs9XhosXlom a7gYCkfXin3EikMo755MmbeskUeIbuvc+t2plmfmHYc3cJHuNc4WRL3RFfuoMBLxduQ== ARC-Authentication-Results: i=2; smtp.subspace.kernel.org; dmarc=none header.from=pengutronix.de; spf=pass smtp.mailfrom=pengutronix.de; dkim=pass header.d=pengutronix.de header.i=@pengutronix.de header.a=rsa-sha256 header.s=20260414 header.b=b0ZlzURX; arc=pass header.oldest-pass=0 smtp.remote-ip=185.203.200.13 Received: from mx1.white.stw.pengutronix.de (mx1.white.stw.pengutronix.de [185.203.200.13]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B3A84606A31E; Mon, 19 Oct 2026 17:08:48 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org B3A84606A31E Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=pengutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=pengutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=pengutronix.de header.i=@pengutronix.de header.a=rsa-sha256 header.s=20260414 header.b=b0ZlzURX Received: from drehscheibe.grey.stw.pengutronix.de (drehscheibe.grey.stw.pengutronix.de [IPv6:2a0a:edc0:0:c01:1d::a2]) (Authenticated sender: relay-from-drehscheibe.grey.stw.pengutronix.de) by mx1.white.stw.pengutronix.de (Postfix) with ESMTPSA id BFBE0202849; Mon, 19 Oct 2026 19:08:36 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=pengutronix.de; s=20260414; t=1792429716; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=zrvCeDlbEo1dcdadZUxg0hKYtY32Q9aSGECGIN22EA4=; b=b0ZlzURXSUfjJuo2k6z/Q/MlWLA3dSksxfj4nzPLOf0pwX/+1p1gWYOWaPTyYwjmaZ8c0D kqeafWpi/87TzvB+J/fZgkksMPpEwN5yM8mXYb5F/dl7UD4XBK+Xos0WZiERN5FKyJcVb3 9g0+X51nvJimODbJ2lfofnFlA60GpYXKcOUiKmB3i1mr08VOzeBH+zd8Z4hVBYno0D7BgV RQxvTJvDAXs/Lohpj6N7Idc79M+fqEq61oGPCAxfXqvsZUoT8lPDCvA+36/lnmnRsg+u+A vA78+3GHV312UrUpw5zTX7b9V4fOf8Dqe+uAPYEByZfrOUWFB98qHcynbn76nw== ARC-Seal: i=1; s=20260414; d=pengutronix.de; t=1792429716; a=rsa-sha256; cv=none; b=bZGObe00i2N9tNnmXvCRXFsVBT1qECfO3ErhZzNnpgJHqIwBYRqxHoa+j0o3EZkc5W6Suk 8r938+bn2XSSOI14vdWxkecjZ6nvZ0eu/h8Slq0EzxfsyFyWdZIXnFdQxl7ZbBxQwwRGIf lTRJDkhh+B8Y98dmFrDZDZtIqAOvTlRUDeyjZKp5lnlByOSXV/4332msbfZmhYrjDNLC6f COj4aJAQJetLw3cf4e516mBc04G9MmNntWG+MHL+6xN0os8mpanv7rlz8Zhsh9CgedEdpR iqBIGZign5DjlK+zJJwsVUPwFoJTZ8myyyJrlI3TD3YlQH+kK/h/XsURr85X/Q== ARC-Authentication-Results: i=1; ORIGINATING; auth=pass smtp.auth=relay-from-drehscheibe.grey.stw.pengutronix.de smtp.mailfrom=mkl@pengutronix.de ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=pengutronix.de; s=20260414; t=1792429716; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=zrvCeDlbEo1dcdadZUxg0hKYtY32Q9aSGECGIN22EA4=; b=SGWEjMg02Ta3iSs4k4lThwkLqfioP6B9OqItJ7y+Z6VPnDbW1bLFuvLWi0ykhWlZUE1lcn JXuoE451POqxZrJf9X8pi+7i5+D94v+v/fIZQVssi0udBq+RnnaXdOFSNjIW0tUNJSTs7S ky0h6PEgcpb4kfwbmc97kALItz8JmwjsQAcCdjnUAdok8/rtcpbLmBsvFIJmsx/YMp4KLl ctRFcG1Gkns88u1jnVs6S715r5LhHu2lFIcuFQc9eMj/e5h0MzVK9qSftdUNs70YhmA1H8 hi6S5U1yn4l+jZYPrweLpvki6nihB4bSf3hhp1UZjegtvxyBjYeeLp54skkH8Q== Received: from moin.white.stw.pengutronix.de ([2a0a:edc0:0:b01:1d::7b] helo=bjornoya.blackshift.org) by drehscheibe.grey.stw.pengutronix.de with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1xIqqi-000Fg9-28; Mon, 19 Oct 2026 19:08:36 +0200 Received: from blackshift.org (p4ffb23c7.dip0.t-ipconnect.de [79.251.35.199]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519MLKEM768 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) (Authenticated sender: mkl-all@blackshift.org) by smtp.blackshift.org (Postfix) with ESMTPSA id 6393E5C948B; Mon, 19 Oct 2026 17:08:36 +0000 (UTC) From: Marc Kleine-Budde To: netdev@vger.kernel.org Cc: davem@davemloft.net, kuba@kernel.org, linux-can@vger.kernel.org, kernel@pengutronix.de, Vincent Mailhol , stable@kernel.org, Marc Kleine-Budde Subject: [PATCH net-next 01/11] can: dev: can_dropped_invalid_skb: drop CAN XL frames on non-CAN XL devices Date: Mon, 19 Oct 2026 19:01:06 +0200 Message-ID: <20261019170834.1727150-2-mkl@pengutronix.de> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261019170834.1727150-1-mkl@pengutronix.de> References: <20261019170834.1727150-1-mkl@pengutronix.de> X-Mailing-List: netdev@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Vincent Mailhol Sending a PF_PACKET bypasses the CAN framework logic and can directly reach a CAN driver's xmit() function. The PF_PACKET framework only checks that skb->len does not exceed the net_device MTU. For a CAN device that is not CAN XL capable, anything above CANFD_MTU (72 bytes) is therefore dropped before it reaches the driver. However, CAN XL frames are variable length. can_is_canxl_skb() accepts lengths in the range CANXL_HDR_SIZE + CANXL_MIN_DLEN up to CANXL_MTU, i.e. 13 to 2060 bytes. As a result, an ETH_P_CANXL skb with a length between 13 and 72 bytes can pass both the MTU and the can_dropped_invalid_skb() checks. A driver that does not support CAN XL will interpret canxl_frame->flags as a length because of the overlap with can_frame->len. And because CANXL_XLF is set, the resulting length is between 128 and 255. For drivers that do not check can_frame->len before copying can_frame->data, as most drivers do, this results in a buffer overflow of up to 247 bytes. Drop ETH_P_CANXL skbs if the device does not have the CAN_CAP_XL capability. Keep can_is_canxl_skb() for the validation of CAN XL skbs. Closes: https://sashiko.dev/#/patchset/20260731-master-v5-0-5b27029dee20@qq.com?part=1 Fixes: fb08cba12b52 ("can: canxl: update CAN infrastructure for CAN XL frames") Signed-off-by: Vincent Mailhol Link: https://patch.msgid.link/20260731-drop_canxl_frames-v1-1-7387b70353b3@kernel.org Cc: stable@kernel.org Signed-off-by: Marc Kleine-Budde --- drivers/net/can/dev/skb.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/net/can/dev/skb.c b/drivers/net/can/dev/skb.c index 14edec5afb57..bc0787535b52 100644 --- a/drivers/net/can/dev/skb.c +++ b/drivers/net/can/dev/skb.c @@ -4,6 +4,7 @@ * Copyright (C) 2008-2009 Wolfgang Grandegger */ +#include #include #include #include @@ -388,7 +389,7 @@ bool can_dropped_invalid_skb(struct net_device *dev, struct sk_buff *skb) break; case ETH_P_CANXL: - if (!can_is_canxl_skb(skb)) + if (!can_cap_enabled(dev, CAN_CAP_XL) || !can_is_canxl_skb(skb)) goto inval_skb; break; base-commit: 98c2ad4f5d805dbc1ea436a334ee59311806a48c -- 2.53.0