From 137086f25c8aa52e4222355345e4218e410188c5 Mon Sep 17 00:00:00 2001 From: Shaurya Rane Date: Wed, 26 Nov 2025 02:06:51 +0530 Subject: [PATCH] net/sched: em_canid: add length check before reading CAN ID 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