[PATCH net-next v1 3/4] net: hsr: require valid EOT supervision TLV

luka.gejak
2026-03-24T14:35:33Z

Supervision frames are only valid if terminated with a zero-length EOT
TLV. The current check fails to reject non-EOT entries as the terminal
TLV, potentially allowing malformed supervision traffic.

Fix this by strictly requiring the terminal TLV to be HSR_TLV_EOT
with a length of zero.

Signed-off-by: Luka Gejak <luka.gejak@linux.dev>
---
net/hsr/hsr_forward.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/hsr/hsr_forward.c b/net/hsr/hsr_forward.c
index aefc9b6936ba..d26c7d0e8109 100644
--- a/net/hsr/hsr_forward.c
+++ b/net/hsr/hsr_forward.c
@@ -110,7 +110,7 @@ static bool is_supervision_frame(struct hsr_priv *hsr, struct sk_buff *skb)
}

/* end of tlvs must follow at the end */
- if (hsr_sup_tlv->HSR_TLV_type == HSR_TLV_EOT &&
+ if (hsr_sup_tlv->HSR_TLV_type != HSR_TLV_EOT ||
hsr_sup_tlv->HSR_TLV_length != 0)
return false;

--
2.53.0