diff options
| author | Ruide Cao <caoruide123@gmail.com> | 2026-04-02 22:46:20 +0800 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2026-04-03 14:34:56 -0700 |
| commit | c842743d073bdd683606cb414eb0ca84465dd834 (patch) | |
| tree | 92df6a187145665860ac055dedc15b165d844278 | |
| parent | 51f4e090b9f87b40c21b6daadb5c06e6c0a07b67 (diff) | |
net: sched: act_csum: validate nested VLAN headers
tcf_csum_act() walks nested VLAN headers directly from skb->data when an
skb still carries in-payload VLAN tags. The current code reads
vlan->h_vlan_encapsulated_proto and then pulls VLAN_HLEN bytes without
first ensuring that the full VLAN header is present in the linear area.
If only part of an inner VLAN header is linearized, accessing
h_vlan_encapsulated_proto reads past the linear area, and the following
skb_pull(VLAN_HLEN) may violate skb invariants.
Fix this by requiring pskb_may_pull(skb, VLAN_HLEN) before accessing and
pulling each nested VLAN header. If the header still is not fully
available, drop the packet through the existing error path.
Fixes: 2ecba2d1e45b ("net: sched: act_csum: Fix csum calc for tagged packets")
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Co-developed-by: Yuan Tan <yuantan098@gmail.com>
Signed-off-by: Yuan Tan <yuantan098@gmail.com>
Suggested-by: Xin Liu <bird@lzu.edu.cn>
Tested-by: Ren Wei <enjou1224z@gmail.com>
Signed-off-by: Ruide Cao <caoruide123@gmail.com>
Signed-off-by: Ren Wei <n05ec@lzu.edu.cn>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/22df2fcb49f410203eafa5d97963dd36089f4ecf.1774892775.git.caoruide123@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/sched/act_csum.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/net/sched/act_csum.c b/net/sched/act_csum.c index 213e1ce9d2da..a9e4635d899e 100644 --- a/net/sched/act_csum.c +++ b/net/sched/act_csum.c @@ -604,8 +604,12 @@ again: protocol = skb->protocol; orig_vlan_tag_present = true; } else { - struct vlan_hdr *vlan = (struct vlan_hdr *)skb->data; + struct vlan_hdr *vlan; + if (!pskb_may_pull(skb, VLAN_HLEN)) + goto drop; + + vlan = (struct vlan_hdr *)skb->data; protocol = vlan->h_vlan_encapsulated_proto; skb_pull(skb, VLAN_HLEN); skb_reset_network_header(skb); |