Merge branch 'bpf-sockmap-reject-a-packet-modifying-sk_skb-stream-parser'

Sechang Lim says:

====================
bpf, sockmap: reject a packet-modifying SK_SKB stream parser

A BPF_PROG_TYPE_SK_SKB stream parser runs on strparser's message head,
which can chain skbs through frag_list. A parser that resizes the skb
frees the frag_list segments that strparser still tracks through
skb_nextp, leading to a use-after-free.

A stream parser is only meant to measure the next message, not to modify
the packet, so reject a packet-modifying parser at attach time.

v5:
 - target bpf-next instead of bpf
 - add Reviewed-by tag (Jiayuan Chen)

v4:
 - https://lore.kernel.org/all/20260619062959.3277612-1-rhkrqnwk98@gmail.com/

v3:
 - https://lore.kernel.org/all/20260618102718.2331468-1-rhkrqnwk98@gmail.com/

v2:
 - https://lore.kernel.org/all/20260612123553.2724240-1-rhkrqnwk98@gmail.com/

v1:
 - https://lore.kernel.org/all/20260609112316.3685738-1-rhkrqnwk98@gmail.com/
====================

Link: https://patch.msgid.link/20260620024423.4141004-1-rhkrqnwk98@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>