tree 82f60b8affcd22b63b7fc14a721e4415c0fabef4
parent 93fbc16e34552f4d1780a900a0dce58fe03ed441
author Alexei Starovoitov <ast@kernel.org> 1680307734 -0700
committer Alexei Starovoitov <ast@kernel.org> 1680307734 -0700

bpf: Teach verifier that certain helpers accept NULL pointer.

bpf_[sk|inode|task|cgrp]_storage_[get|delete]() and bpf_get_socket_cookie() helpers
perform run-time check that sk|inode|task|cgrp pointer != NULL.
Teach verifier about this fact and allow bpf programs to pass
PTR_TO_BTF_ID | PTR_MAYBE_NULL into such helpers.
It will be used in the subsequent patch that will do
bpf_sk_storage_get(.., skb->sk, ...);
Even when 'skb' pointer is trusted the 'sk' pointer may be NULL.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>