From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pj1-f67.google.com (mail-pj1-f67.google.com [209.85.216.67]) (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 4D1F51F3BAC for ; Wed, 26 Nov 2025 03:46:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.216.67 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764128773; cv=none; b=tQL/blItSw4hqwUQS1xSpq4PnGZQrtKyTAZxanClIcQhW7EDjEN88HTERM1XfpJo8ZQepwv4KbayHdXvp+myfiPizT/dzXerSJrotCQKDumQondJ20Hfb3JlzTmcnz9GqC49kOIGCRANY9z7elcjmnHyW2Kg+izGcjduxCmVfhg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764128773; c=relaxed/simple; bh=YTJTsaHQmUL99NvK8+4VZBxoWMvT0DJLWraueRWowDQ=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=USMLS0N510KLOaTVFdJWKhRO9gtqv0wx+quWenyOcM9QDWYntlodv8xKsl3eJUyBT0lf2J9oiTJSH7orv4zr3tJgLPJlWx9uzZFqlZ2GXVd11aou6IdhXLwnAXSlpkxtp+kRYu4sqw5d1VymI9w6lJN2+mDP7Tbn1janm1Sfj9Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=ee.vjti.ac.in; spf=none smtp.mailfrom=ee.vjti.ac.in; dkim=pass (1024-bit key) header.d=vjti.ac.in header.i=@vjti.ac.in header.b=Cr+ARicE; arc=none smtp.client-ip=209.85.216.67 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=ee.vjti.ac.in Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=ee.vjti.ac.in Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=vjti.ac.in header.i=@vjti.ac.in header.b="Cr+ARicE" Received: by mail-pj1-f67.google.com with SMTP id 98e67ed59e1d1-3436d6ca17bso6157392a91.3 for ; Tue, 25 Nov 2025 19:46:12 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=vjti.ac.in; s=google; t=1764128771; x=1764733571; darn=lists.linux.dev; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=/0OQa00OisAI9Yf2BGn0QlVHZWUx/PRSa3ljqdERpcQ=; b=Cr+ARicE149NhCQSzyRjfjz6x1hhWyM4bforBchijbUMxr4ogzk8bFO3gURLIwdKmp L4Z6unl5I4sj9+8E5o6sIt09Cd8fi6vIMc3tr5JHWX600AhyTX1fhhvzLRD4mS8nwS/v FfnoJQp/1QcFH28RQjy+GI98292Ag7A9GDkkk= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1764128771; x=1764733571; 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; bh=/0OQa00OisAI9Yf2BGn0QlVHZWUx/PRSa3ljqdERpcQ=; b=QPSW+uM7kq0QX8yX/BLDSJ83QuCLZ2zgBWt2QTbXoIYYZsfXIEBp3HPWh8uXxlJzI2 22fUaUH2HsUQS6K0F9AsALPpVFigt7owfS5QBd55phLyc5CLIBwJTG/paHHYcijsHR3g cNrTi0nRdDihViSkKjSNlUvxm6q9DZ3SJP+uqCkGQmE4rIIjTowK3cCy3xBszl4um07b INNDFiBzwW5hrbeWHcivVbCe2zKwSpRRNyrRfdMCW5ld9xgZ7IZLZljcKFEdSEBx231o YjdfogZbkUQlzhQeAtKuyK5T4qrhNeNFSRoXyAhiAQJ3rym9XAOiNdj/ie610wias0+t lFKg== X-Forwarded-Encrypted: i=1; AJvYcCVAeCjRg0GTxIvDTf8hHeYH//HXtVEXyagPjCZKp4npLJgRIYPqPboOvy3somOvHJTEsEdphGeULcarOVjzaddIxTCyYg==@lists.linux.dev X-Gm-Message-State: AOJu0YxkFjXYkYf2EJh8TwMd8yE5G2VGNdsr6x+t3r/Pr3d9uhFQKQxT 2bkkPEqEutZHQBdubewAGlQmdZISIAD2bxgQZfMou76saS26vilij5t84H2HbITmVEo= X-Gm-Gg: ASbGnct6iM3yBQqlGQQZNDHli3TWjylY1PfQODY7LzLJot7F5kykPuROwxy2CGWdVc9 2SnIlG5iT1CecnsezqY1YbnA0FtLGGCohENT2DaBd3P9U5aZQRFEwFEUM2bSzTwlCR6CLiuYhJO jxgah62uN+33aPIesMLPC/j/RE5m5KFLXBFqubzjYLCNma9TzFZnNdJLvnQIxS7MYckjo2bwLWW wSijqELzXvCwW1JY/tzla+BIDsACqz5XOznDAslnfzuPOP6lqgald8nvj9UgacM6BXgSwVo30xw qF12rwtVU9D9PQ/4tRqMrN+doyWQti6LRsw389dtICDM5TAZpFKU53eif9hFELWAQTNAM4aYVxC LUHmAkS2KUC49+VgejMXLekEOrdc/kn4GxKLlB5oIBA52KOWFBb+KfFq0BYSGrymFbVR9hTNysa Pc5UZ9jCBI9Z6V282wsBjijds0iHG3PFsUsB5AaaUZmVDpdH+A0zsG6+5Q X-Google-Smtp-Source: AGHT+IGdbZpTaNhkORvuwsJtkl/0aqTP4Z+/MfLQ2cdKMWZ8EnjRZs396Kq3PBwRLHF0A7Z5HsdZeA== X-Received: by 2002:a17:90b:53c3:b0:33b:b020:597a with SMTP id 98e67ed59e1d1-34733d68a15mr15410786a91.0.1764128771454; Tue, 25 Nov 2025 19:46:11 -0800 (PST) Received: from ranegod-HP-ENVY-x360-Convertible-13-bd0xxx.. ([2405:201:31:d869:f53f:2666:7529:e5cd]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-3475ea1b3e8sm1509638a91.5.2025.11.25.19.46.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 25 Nov 2025 19:46:10 -0800 (PST) From: ssrane_b23@ee.vjti.ac.in X-Google-Original-From: ssranevjti@gmail.com To: socketcan@hartkopp.net Cc: mkl@pengutronix.de, jhs@mojatatu.com, xiyou.wangcong@gmail.com, jiri@resnulli.us, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, linux-can@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, skhan@linuxfoundation.org, linux-kernel-mentees@lists.linux.dev, david.hunter.linux@gmail.com, khalid@kernel.org, Shaurya Rane , syzbot+5d8269a1e099279152bc@syzkaller.appspotmail.com Subject: [PATCH net] net/sched: em_canid: add length check before reading CAN ID Date: Wed, 26 Nov 2025 09:16:01 +0530 Message-Id: <20251126034601.236922-1-ssranevjti@gmail.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel-mentees@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Shaurya Rane Add a check to verify that the skb has at least sizeof(canid_t) bytes before reading the CAN ID from skb->data. This prevents reading uninitialized memory when processing malformed packets that don't contain a valid CAN frame. Reported-by: syzbot+5d8269a1e099279152bc@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=5d8269a1e099279152bc Fixes: f057bbb6f9ed ("net: em_canid: Ematch rule to match CAN frames according to their identifiers") Signed-off-by: Shaurya Rane --- net/sched/em_canid.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/net/sched/em_canid.c b/net/sched/em_canid.c index 5337bc462755..a9b6cab70ff1 100644 --- a/net/sched/em_canid.c +++ b/net/sched/em_canid.c @@ -99,6 +99,9 @@ static int em_canid_match(struct sk_buff *skb, struct tcf_ematch *m, int i; const struct can_filter *lp; + if (skb->len < sizeof(canid_t)) + return 0; + can_id = em_canid_get_id(skb); if (can_id & CAN_EFF_FLAG) { -- 2.34.1