Re: [syzbot] Re: [syzbot] [net?] KMSAN: uninit-value in hsr_get_node (3)

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-kernel@xxxxxxxxxxxxxxx.

***

Subject: Re: [syzbot] [net?] KMSAN: uninit-value in hsr_get_node (3)
Author: aha310510@xxxxxxxxx

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

---
 net/hsr/hsr_framereg.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/hsr/hsr_framereg.c b/net/hsr/hsr_framereg.c
index 73bc6f659812..b7d5b9da881a 100644
--- a/net/hsr/hsr_framereg.c
+++ b/net/hsr/hsr_framereg.c
@@ -224,6 +224,9 @@ struct hsr_node *hsr_get_node(struct hsr_port *port, struct list_head *node_db,
 	if (!skb_mac_header_was_set(skb))
 		return NULL;
 
+	if (skb->max_len < sizeof(struct ethhdr))
+		return NULL;
+
 	ethhdr = (struct ethhdr *)skb_mac_header(skb);
 
 	list_for_each_entry_rcu(node, node_db, mac_list) {
--