From: Phillip Potter <phil@xxxxxxxxxxxxxxxx> [ Upstream commit 2e9f60932a2c19e8a11b4a69d419f107024b05a0 ] Check at start of fill_frame_info that the MAC header in the supplied skb is large enough to fit a struct hsr_ethhdr, as otherwise this is not a valid HSR frame. If it is too small, return an error which will then cause the callers to clean up the skb. Fixes a KMSAN-found uninit-value bug reported by syzbot at: https://syzkaller.appspot.com/bug?id=f7e9b601f1414f814f7602a82b6619a8d80bce3f Reported-by: syzbot+e267bed19bfc5478fb33@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Phillip Potter <phil@xxxxxxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- net/hsr/hsr_forward.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/hsr/hsr_forward.c b/net/hsr/hsr_forward.c index b4e06ae08834..90c72e4c0a8f 100644 --- a/net/hsr/hsr_forward.c +++ b/net/hsr/hsr_forward.c @@ -493,6 +493,10 @@ static int fill_frame_info(struct hsr_frame_info *frame, struct ethhdr *ethhdr; __be16 proto; + /* Check if skb contains hsr_ethhdr */ + if (skb->mac_len < sizeof(struct hsr_ethhdr)) + return -EINVAL; + memset(frame, 0, sizeof(*frame)); frame->is_supervision = is_supervision_frame(port->hsr, skb); frame->node_src = hsr_get_node(port, &hsr->node_db, skb, -- 2.30.2
