From f38499ff45f567c932d0911e6a30b8ca022b9b52 Mon Sep 17 00:00:00 2001 From: Jakub Sitnicki Date: Wed, 5 Nov 2025 21:19:40 +0100 Subject: bpf: Unclone skb head on bpf_dynptr_write to skb metadata Currently bpf_dynptr_from_skb_meta() marks the dynptr as read-only when the skb is cloned, preventing writes to metadata. Remove this restriction and unclone the skb head on bpf_dynptr_write() to metadata, now that the metadata is preserved during uncloning. This makes metadata dynptr consistent with skb dynptr, allowing writes regardless of whether the skb is cloned. Signed-off-by: Jakub Sitnicki Signed-off-by: Martin KaFai Lau Link: https://patch.msgid.link/20251105-skb-meta-rx-path-v4-3-5ceb08a9b37b@cloudflare.com --- kernel/bpf/helpers.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'kernel/bpf/helpers.c') diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index eb25e70e0bdc..3e830fd31f5f 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c @@ -1842,10 +1842,8 @@ int __bpf_dynptr_write(const struct bpf_dynptr_kern *dst, u32 offset, void *src, return -EINVAL; return __bpf_xdp_store_bytes(dst->data, dst->offset + offset, src, len); case BPF_DYNPTR_TYPE_SKB_META: - if (flags) - return -EINVAL; - memmove(bpf_skb_meta_pointer(dst->data, dst->offset + offset), src, len); - return 0; + return __bpf_skb_meta_store_bytes(dst->data, dst->offset + offset, src, + len, flags); default: WARN_ONCE(true, "bpf_dynptr_write: unknown dynptr type %d\n", type); return -EFAULT; -- cgit