[PATCH 6.7 039/162] net: hsr: Use correct offset for HSR TLV values in supervisory HSR frames

Greg Kroah-Hartman
2024-03-04T21:28:39Z

From: Lukasz Majewski <lukma@denx.de>

[ Upstream commit 51dd4ee0372228ffb0f7709fa7aa0678d4199d06 ]

Current HSR implementation uses following supervisory frame (even for
HSRv1 the HSR tag is not is not present):

00000000: 01 15 4e 00 01 2d XX YY ZZ 94 77 10 88 fb 00 01
00000010: 7e 1c 17 06 XX YY ZZ 94 77 10 1e 06 XX YY ZZ 94
00000020: 77 10 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000030: 00 00 00 00 00 00 00 00 00 00 00 00

The current code adds extra two bytes (i.e. sizeof(struct hsr_sup_tlv))
when offset for skb_pull() is calculated.
This is wrong, as both 'struct hsrv1_ethhdr_sp' and 'hsrv0_ethhdr_sp'
already have 'struct hsr_sup_tag' defined in them, so there is no need
for adding extra two bytes.

This code was working correctly as with no RedBox support, the check for
HSR_TLV_EOT (0x00) was off by two bytes, which were corresponding to
zeroed padded bytes for minimal packet size.

Fixes: eafaa88b3eb7 ("net: hsr: Add support for redbox supervision frames")
Signed-off-by: Lukasz Majewski <lukma@denx.de>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Link: https://lore.kernel.org/r/20240228085644.3618044-1-lukma@denx.de
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 80cdc6f6b34c9..0323ab5023c69 100644
--- a/net/hsr/hsr_forward.c
+++ b/net/hsr/hsr_forward.c
@@ -83,7 +83,7 @@ static bool is_supervision_frame(struct hsr_priv *hsr, struct sk_buff *skb)
return false;

/* Get next tlv */
- total_length += sizeof(struct hsr_sup_tlv) + hsr_sup_tag->tlv.HSR_TLV_length;
+ total_length += hsr_sup_tag->tlv.HSR_TLV_length;
if (!pskb_may_pull(skb, total_length))
return false;
skb_pull(skb, total_length);
--
2.43.0