From: ssrane_b23@ee.vjti.ac.in
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 <ssrane_b23@ee.vjti.ac.in>,
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 [thread overview]
Message-ID: <20251126034601.236922-1-ssranevjti@gmail.com> (raw)
From: Shaurya Rane <ssrane_b23@ee.vjti.ac.in>
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 <ssrane_b23@ee.vjti.ac.in>
---
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
next reply other threads:[~2025-11-26 3:46 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-26 3:46 ssrane_b23 [this message]
2025-11-26 4:16 ` [PATCH net] net/sched: em_canid: add length check before reading CAN ID Eric Dumazet
2025-11-26 4:59 ` SHAURYA RANE
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