Commit 8cfc172c authored by Jakub Sitnicki's avatar Jakub Sitnicki Committed by Martin KaFai Lau
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bpf: Make bpf_skb_change_proto helper metadata-safe 



bpf_skb_change_proto reuses the same headroom operations as
bpf_skb_adjust_room, already updated to handle metadata safely.

The remaining step is to ensure that there is sufficient headroom to
accommodate metadata on skb_push().

Signed-off-by: default avatarJakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: default avatarMartin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20251105-skb-meta-rx-path-v4-8-5ceb08a9b37b@cloudflare.com
parent be83105d

net/core/filter.c

+2 −1
Original line number Diff line number Diff line
@@ -3326,10 +3326,11 @@ static int bpf_skb_net_hdr_pop(struct sk_buff *skb, u32 off, u32 len) 
static int bpf_skb_proto_4_to_6(struct sk_buff *skb)

{

	const u32 len_diff = sizeof(struct ipv6hdr) - sizeof(struct iphdr);

	const u8 meta_len = skb_metadata_len(skb);

	u32 off = skb_mac_header_len(skb);

	int ret;



	ret = skb_cow(skb, len_diff);

	ret = skb_cow(skb, meta_len + len_diff);

	if (unlikely(ret < 0))

		return ret;