bpf: Make bpf_skb_vlan_pop helper metadata-safe

jsitnicki · Kernel Patches Daemon · commit 674d02938b3e · 2025-11-05T12:24:10.000-08:00
Use the metadata-aware helper to move packet bytes after skb_pull(),
ensuring metadata remains valid after calling the BPF helper.

Signed-off-by: Jakub Sitnicki &lt;jakub@cloudflare.com&gt;
diff --git a/include/linux/if_vlan.h b/include/linux/if_vlan.h
@@ -738,9 +738,9 @@ static inline void vlan_remove_tag(struct sk_buff *skb, u16 *vlan_tci)
 
 	*vlan_tci = ntohs(vhdr->h_vlan_TCI);
 
-	memmove(skb->data + VLAN_HLEN, skb->data, 2 * ETH_ALEN);
 	vlan_set_encap_proto(skb, vhdr);
 	__skb_pull(skb, VLAN_HLEN);
+	skb_postpull_data_move(skb, VLAN_HLEN, 2 * ETH_ALEN);
 }
 
 /**

Original file line number	Diff line number	Diff line change
`@@ -738,9 +738,9 @@ static inline void vlan_remove_tag(struct sk_buff skb, u16 vlan_tci)`
`738`	`738`
`739`	`739`	`*vlan_tci = ntohs(vhdr->h_vlan_TCI);`
`740`	`740`
`741`		`- memmove(skb->data + VLAN_HLEN, skb->data, 2 * ETH_ALEN);`
`742`	`741`	`vlan_set_encap_proto(skb, vhdr);`
`743`	`742`	`__skb_pull(skb, VLAN_HLEN);`
	`743`	`+ skb_postpull_data_move(skb, VLAN_HLEN, 2 * ETH_ALEN);`
`744`	`744`	`}`
`745`	`745`
`746`	`746`	`/**`