From: Jakub Sitnicki Date: Wed, 5 Nov 2025 20:19:43 +0000 (+0100) Subject: bpf: Make bpf_skb_vlan_push helper metadata-safe X-Git-Tag: v6.19-rc1~170^2~199^2~1^2~10 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=55ffc98b44d28e13a218306666d16f2c7236d0ae;p=thirdparty%2Fkernel%2Flinux.git bpf: Make bpf_skb_vlan_push helper metadata-safe Use the metadata-aware helper to move packet bytes after skb_push(), ensuring metadata remains valid after calling the BPF helper. Also, take care to reserve sufficient headroom for metadata to fit. Signed-off-by: Jakub Sitnicki Signed-off-by: Martin KaFai Lau Link: https://patch.msgid.link/20251105-skb-meta-rx-path-v4-6-5ceb08a9b37b@cloudflare.com --- diff --git a/include/linux/if_vlan.h b/include/linux/if_vlan.h index 4ecc2509b0d43..f7f34eb15e068 100644 --- a/include/linux/if_vlan.h +++ b/include/linux/if_vlan.h @@ -355,16 +355,17 @@ static inline int __vlan_insert_inner_tag(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci, unsigned int mac_len) { + const u8 meta_len = mac_len > ETH_TLEN ? skb_metadata_len(skb) : 0; struct vlan_ethhdr *veth; - if (skb_cow_head(skb, VLAN_HLEN) < 0) + if (skb_cow_head(skb, meta_len + VLAN_HLEN) < 0) return -ENOMEM; skb_push(skb, VLAN_HLEN); /* Move the mac header sans proto to the beginning of the new header. */ if (likely(mac_len > ETH_TLEN)) - memmove(skb->data, skb->data + VLAN_HLEN, mac_len - ETH_TLEN); + skb_postpush_data_move(skb, VLAN_HLEN, mac_len - ETH_TLEN); if (skb_mac_header_was_set(skb)) skb->mac_header -= VLAN_HLEN;