netfilter, bpf: Adjust timeouts of non-confirmed CTs in bpf_ct_insert_entry()

netfilter, bpf: Adjust timeouts of non-confirmed CTs in bpf_ct_insert_entry()

bpf_nf testcase fails on s390x: bpf_skb_ct_lookup() cannot find the entry
that was added by bpf_ct_insert_entry() within the same BPF function.

The reason is that this entry is deleted by nf_ct_gc_expired().

The CT timeout starts ticking after the CT confirmation; therefore
nf_conn.timeout is initially set to the timeout value, and
__nf_conntrack_confirm() sets it to the deadline value.

bpf_ct_insert_entry() sets IPS_CONFIRMED_BIT, but does not adjust the
timeout, making its value meaningless and causing false positives.

Fix the problem by making bpf_ct_insert_entry() adjust the timeout,
like __nf_conntrack_confirm().

Fixes: 2cdaa3eefed8 ("netfilter: conntrack: restore IPS_CONFIRMED out of nf_conntrack_hash_check_insert()")
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Florian Westphal <fw@strlen.de>
Link: https://lore.kernel.org/bpf/20230830011128.1415752-3-iii@linux.ibm.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>