On Mon, 2023-12-04 at 15:39 -0800, Andrii Nakryiko wrote:
> Remove duplicated BTF parsing logic when it comes to subprog call check.
> Instead, use (potentially cached) results of btf_prepare_func_args() to
> abstract away expectations of each subprog argument in generic terms
> (e.g., "this is pointer to context", or "this is a pointer to memory of
> size X"), and then use those simple high-level argument type
> expectations to validate actual register states to check if they match
> expectations.
>
> Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
> ---
Acked-by: Eduard Zingerman <eddyz87@xxxxxxxxx>
> kernel/bpf/verifier.c | 109 ++++++------------
> .../selftests/bpf/progs/test_global_func5.c | 2 +-
> 2 files changed, 37 insertions(+), 74 deletions(-)
>
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index 2103f94b605b..5787b7fd16ba 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -9214,21 +9214,23 @@ static int setup_func_entry(struct bpf_verifier_env *env, int subprog, int calls
> return err;
> }
>
> -static int btf_check_func_arg_match(struct bpf_verifier_env *env,
> +static int btf_check_func_arg_match(struct bpf_verifier_env *env, int subprog,
> const struct btf *btf, u32 func_id,
> - struct bpf_reg_state *regs,
> - bool ptr_to_mem_ok)
> + struct bpf_reg_state *regs)
Nit: It looks like 'func_id' is always 'prog->aux->func_info[subprog].type_id'.
Maybe remove this parameter and retrieve func_id inside this function?
Or at-least, could you please rename it to subprog_btf_id?
For me names 'subprog' and 'func_id' seem interchangeable and thus confusing.
