[PATCH bpf-next v1 2/4] bpf: Allow verifier to fixup kernel module kfuncs

[Amery Hung <ameryhung@gmail.com>]

Allow verifier to fixup kfuncs in kernel module to support kfuncs with
__prog arguments. Currently, special kfuncs and kfuncs with __prog
arguments are kernel kfuncs. As there is no safety reason that prevents
a kernel module kfunc from accessing prog->aux, allow it by removing the
kernel BTF check.

Signed-off-by: Amery Hung <ameryhung@gmail.com>
---
 kernel/bpf/verifier.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index f6d3655b3a7a..54adb479315b 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -21467,8 +21467,7 @@ static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn,
 
 	if (!bpf_jit_supports_far_kfunc_call())
 		insn->imm = BPF_CALL_IMM(desc->addr);
-	if (insn->off)
-		return 0;
+
 	if (desc->func_id == special_kfunc_list[KF_bpf_obj_new_impl] ||
 	    desc->func_id == special_kfunc_list[KF_bpf_percpu_obj_new_impl]) {
 		struct btf_struct_meta *kptr_struct_meta = env->insn_aux_data[insn_idx].kptr_struct_meta;
-- 
2.47.1