diff options
| author | Jakub Sitnicki <jakub@cloudflare.com> | 2025-11-05 21:19:40 +0100 |
|---|---|---|
| committer | Martin KaFai Lau <martin.lau@kernel.org> | 2025-11-10 10:52:31 -0800 |
| commit | f38499ff45f567c932d0911e6a30b8ca022b9b52 (patch) | |
| tree | 54832a54e7699c664e5163dacb10e7b829a7d133 /net/core | |
| parent | 290fc0be09e2f6e08754782616bb7e67f8191fa1 (diff) | |
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 <jakub@cloudflare.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20251105-skb-meta-rx-path-v4-3-5ceb08a9b37b@cloudflare.com
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/filter.c | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/net/core/filter.c b/net/core/filter.c index 52721efba332..673299fd3d58 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -12102,6 +12102,18 @@ void *bpf_skb_meta_pointer(struct sk_buff *skb, u32 offset) return skb_metadata_end(skb) - skb_metadata_len(skb) + offset; } +int __bpf_skb_meta_store_bytes(struct sk_buff *skb, u32 offset, + const void *from, u32 len, u64 flags) +{ + if (unlikely(flags)) + return -EINVAL; + if (unlikely(bpf_try_make_writable(skb, 0))) + return -EFAULT; + + memmove(bpf_skb_meta_pointer(skb, offset), from, len); + return 0; +} + __bpf_kfunc_start_defs(); __bpf_kfunc int bpf_dynptr_from_skb(struct __sk_buff *s, u64 flags, struct bpf_dynptr *ptr__uninit) @@ -12129,9 +12141,6 @@ __bpf_kfunc int bpf_dynptr_from_skb(struct __sk_buff *s, u64 flags, * XDP context with bpf_xdp_adjust_meta(). Serves as an alternative to * &__sk_buff->data_meta. * - * If passed @skb_ is a clone which shares the data with the original, the - * dynptr will be read-only. This limitation may be lifted in the future. - * * Return: * * %0 - dynptr ready to use * * %-EINVAL - invalid flags, dynptr set to null @@ -12149,9 +12158,6 @@ __bpf_kfunc int bpf_dynptr_from_skb_meta(struct __sk_buff *skb_, u64 flags, bpf_dynptr_init(ptr, skb, BPF_DYNPTR_TYPE_SKB_META, 0, skb_metadata_len(skb)); - if (skb_cloned(skb)) - bpf_dynptr_set_rdonly(ptr); - return 0; } |