bpf: Enable read/write access to skb metadata through a dynptr

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Now that we can create a dynptr to skb metadata, make reads to the metadata
area possible with bpf_dynptr_read() or through a bpf_dynptr_slice(), and
make writes to the metadata area possible with bpf_dynptr_write() or
through a bpf_dynptr_slice_rdwr().

Note that for cloned skbs which share data with the original, we limit the
skb metadata dynptr to be read-only since we don't unclone on a
bpf_dynptr_write to metadata.

Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20250814-skb-metadata-thru-dynptr-v7-2-8a39e636e0fb@cloudflare.com

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Jakub Sitnicki 2025-08-14 11:59:28 +02:00 • committed by Martin KaFai Lau

parent 89d912e494

commit 6877cd392b

3 changed files with 29 additions and 3 deletions

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6

include/linux/filter.h

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10

kernel/bpf/helpers.c

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16

net/core/filter.c

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