selftests/bpf: Cover small conntrack opts error writes

Add a conntrack kfunc regression check for opts__sz values that do not
cover opts->error. The BPF program initializes opts->error with a guard
value, calls the lookup and allocation kfuncs with opts__sz set to
sizeof(opts->netns_id), and verifies that the guard is still intact
after the kfunc returns NULL.

Without the conntrack wrapper guard, the kfunc error path overwrites
that guard with -EINVAL even though the verifier checked only the first
four bytes of the options object.

Fixes: b4c2b9593a1c ("net/netfilter: Add unstable CT lookup helpers for XDP and TC-BPF")
Fixes: d7e79c97c00c ("net: netfilter: Add kfuncs to allocate and insert CT")
Signed-off-by: Yiyang Chen <chenyy23@mails.tsinghua.edu.cn>
Link: https://lore.kernel.org/r/007dfd0341cd84560e4795a2a951cc56d4adff1d.1781765747.git.chenyy23@mails.tsinghua.edu.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

0 files changed, 0 insertions, 0 deletions