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=1794273193; b=ZMNd5eOCOieJSxXojc9QKvdlpyQnMwfcUobumryLgIMvAcLSS5zNFR1ri9C7i6Q9MRVx tVfg1NGftO3yCw+cVaEnnj0G8HvmiGT9wroJxH00WOWDuEUXssDxrH/1pDU2aF8uofYdj 5D1F3iGzdnANtmPWM5KRGyuFTn4sxv2KxMWF7mf1Hm2O0DB1KIvjTfpWzb9WaCUUeYluh 5ew6FPxnxkU3jOcZNUutAiUOsEM78PYFYgpUTwV2sW6K18FHoPqADztUtPXSYyvEgEV7i gN34bbrYcwpkUkDoSk2xIzBDj3Pb0Az+SsLn/E8SmWw3B5LZnkr4YOLbQhnyMnbNLiA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794273193; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=AQZjDUH4yFJYeWgMtCMgsvamkEsgFY3RUumdHg7BNOA=; b=lPi+uDDs+mB8kqajzUpco3nRC7dGuXtDfYdxPPTAc+lMOKc1CnAjnMY+h7dG0ejgVacu bKGeQC+TcGTZkhYnrmu/eOg/rnfezf7/uxfrYgpg2znpPf+aAyQaCFWqaRm/V+kcPErAt yXo0tGqtsKxzBrfIRZH6HlqOaB2t6t/IQEDJ+E1vUYaPuJlLsDqkaBcf75MEo7wmxY02/ rPozBNbZKtFxix8PRwmg0ZNiMGnxBf5sTicERyOuXcTviMBomM0IjZpUlYexvAHTFpP3l fWrv96QQdZm9IAp8WSUIdntt50uH1tFug6nTzzpl3VUJKycLp3pQZGGuvqS7VYU14sA== 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=KzdfQ9b4; 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 7B5A5606A31C for ; Tue, 10 Nov 2026 01:13:13 +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=KzdfQ9b4 Received: by smtp.kernel.org (Postfix) with ESMTPSA id E2B621F0089F; Tue, 10 Nov 2026 01:13:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794273193; bh=AQZjDUH4yFJYeWgMtCMgsvamkEsgFY3RUumdHg7BNOA=; h=From:To:Cc:Subject:Date; b=KzdfQ9b4wjJICnUJ9os1eK2d/H5dfOrBBtgysBRdccAWGabbOQYDqQ1mHDWTdiqDk x9lauzpbxPN1/IYiyXOoTfqg0vOL7JHr5HeoWJ9d57K428Cu5RK8V4epJXKlYAinbE mCqc+sZ5VctxjuOVS0MHD//iv706lpx96+IBprp7OnRo/2iHsZIDtnpDM1o8zSnZOg FHGXLne2biAlxvA6AZMcLQDiR1HmaBlFdchDmzAgSE6CsPefluxL9ZJ101w6BhCV1l NadXgRouD8Qa1RCEhI09BF0JyCiOCp0nNaYVDXKUMpBo5mj/KYuCuHTAvrkcY3kv5M 74Gf3hdnQKlWA== 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 6.6-stable tree Date: Mon, 9 Nov 2026 20:13:11 -0500 Message-ID: <20261109201311-failed-6.6-0fce44e29fce@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 6.6-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-6.6.y git checkout FETCH_HEAD git cherry-pick -x 0fce44e29fce4b07642491b098afb41bd571e4f2 # git commit -s git send-email --to '' --in-reply-to '20261109201311-failed-6.6-0fce44e29fce@kernel.org' --subject-prefix 'PATCH 6.6.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