From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794272688; b=syIBmCtuag4mLDSzwv8Zi2ShSTiDWEMI3uBrjlb99/2c1dH8j7vhEpvmNKufHrUdD8fw ahuyOSzcXglWNRGJI8tSk5swkG854u9WB3hu0LxY2acbZ9gkfHhyNOOVofMtIujk/9YKr xm8AjB5OPqGIVV9piPMvDQlxAawWPWfEwDa0ZH3aVrHuSDFjNtngBFq7eZXzLqDu5NkWU TaUpjBW1GK0wb1zCeWdqFQX0xDZ2x5VJvGmsTjNomI7tlZKLPdvQ9Dl2F03hrwuHHgF4A OPgYHeWbbw3TrWkJub6421Kx043sdkqAYo5DTcG5koclsa5GluV3h5Ewf76+3mZcQew== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794272688; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=S/Axm1uMDdEdnAYqgoNUtjIJr6ICNicUhLU/45+se+o=; b=ZNZ5LXkwKcVSlYREXtdaj231ylH3pR1pDUeKEmFb3lLDyfkcG24SYJOb7K3JLj0arJ15 8ezkvDWUC2cFnDKiKDv2z+86QK5HJk0Su5Q2hs9hTnSi03eRyohFPYHXLGwbkkdYh6qsV q2P3L35k0OkXJ/7coUTwsr//Y9VgeA0vq8EILXa61AomY2Q/+leVJxDDtzMpk42JrF+2W QXb1TrBKXiWqlELV6E1UPAs528mPxUOjTCIWF+wFihIbCD1CS/Jn5bl0OeNCorTtVEKtW BoD++JnMUhOKxMd6uHGGE2GcpHGLhO/U1ZJQRPlzuREi9HzzUmMnkxXcGcYeC97JXqw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=L2bbi1mM; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D7510606A321 for ; Tue, 10 Nov 2026 01:04:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=L2bbi1mM Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4D3181F008A1; Tue, 10 Nov 2026 01:04:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794272687; bh=S/Axm1uMDdEdnAYqgoNUtjIJr6ICNicUhLU/45+se+o=; h=From:To:Cc:Subject:Date; b=L2bbi1mMg23Y9Ps23KMLvkGCKKAqhEYnYcOxM6jancEOVUb5SxhGhOC0fpUACQpRT QP8a4/Qgbv+ZfIPn/LLH0NBBLULxVPhecivgJ84pDOA9p4AFlClgBYE0ADN39pReZt tP/HBAFmx52MvaqKQOgia15PubLpQretzcuMajFIgAENNFn9j5Hwqon6yqmeW8Yceg iA7ChotQLFmi9X9hKhHIm2IPhqMEdAkxtroxNL9WqVGPWy+ujx0v2a4pAoJ0UeuwHZ HVrZEHjSSCHIroaxi3um+aRPXBHmi78A3p1kzBZB4VWd9D4gIge/v7NxnCR2mzCDuV Jem8Ux/o9UWZg== From: Sasha Levin To: mailhol@kernel.org, mkl@pengutronix.de Cc: stable@vger.kernel.org Subject: FAILED: patch "[PATCH] can: dev: can_dropped_invalid_skb: drop CAN XL frames on non-CAN XL devices" failed to apply to 6.18-stable tree Date: Mon, 9 Nov 2026 20:04:46 -0500 Message-ID: <20261109200446-failed-6.18-0fce44e29fce@kernel.org> X-Mailer: git-send-email 2.53.0 X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.18-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.18.y git checkout FETCH_HEAD git cherry-pick -x 0fce44e29fce4b07642491b098afb41bd571e4f2 # git commit -s git send-email --to '' --in-reply-to '20261109200446-failed-6.18-0fce44e29fce@kernel.org' --subject-prefix 'PATCH 6.18.y' 'HEAD^..' Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From 0fce44e29fce4b07642491b098afb41bd571e4f2 Mon Sep 17 00:00:00 2001 From: Vincent Mailhol Date: Fri, 31 Jul 2026 18:29:44 +0200 Subject: [PATCH] can: dev: can_dropped_invalid_skb: drop CAN XL frames on non-CAN XL devices 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 14edec5afb57e..bc0787535b524 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; -- 2.53.0