From: Eduard Zingerman <eddyz87@gmail.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Andrii Nakryiko <andrii@kernel.org>,
bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net,
martin.lau@kernel.org, kernel-team@meta.com
Subject: Re: [PATCH v2 bpf-next 02/10] bpf: reuse btf_prepare_func_args() check for main program BTF validation
Date: Wed, 13 Dec 2023 20:14:26 +0200 [thread overview]
Message-ID: <a23e5753192f152fbb09b98137fd0ecd8932efe5.camel@gmail.com> (raw)
In-Reply-To: <CAEf4Bza2v4=nwkV8BtLd7KvANtz1+j+GahFGYJCyKW93XPqF-A@mail.gmail.com>
On Wed, 2023-12-13 at 10:06 -0800, Andrii Nakryiko wrote:
[...]
> > > @@ -19944,21 +19945,19 @@ static int do_check_common(struct bpf_verifier_env *env, int subprog)
> > > }
> > > }
> > > } else {
> > > + /* if main BPF program has associated BTF info, validate that
> > > + * it's matching expected signature, and otherwise mark BTF
> > > + * info for main program as unreliable
> > > + */
> > > + if (env->prog->aux->func_info_aux) {
> > > + ret = btf_prepare_func_args(env, 0);
> > > + if (ret || sub->arg_cnt != 1 || sub->args[0].arg_type != ARG_PTR_TO_CTX)
> > > + env->prog->aux->func_info_aux[0].unreliable = true;
> > > + }
> >
> > Nit: should this return if ret == -EFAULT?
> >
> >
>
> no, why? I think the old behavior also didn't fail in this case
I think it did, here is an excerpt from the current patch:
- ret = btf_check_subprog_arg_match(env, subprog, regs);
- if (ret == -EFAULT)
- /* unlikely verifier bug. abort.
- * ret == 0 and ret < 0 are sadly acceptable for
- * main() function due to backward compatibility.
- * Like socket filter program may be written as:
- * int bpf_prog(struct pt_regs *ctx)
- * and never dereference that ctx in the program.
- * 'struct pt_regs' is a type mismatch for socket
- * filter that should be using 'struct __sk_buff'.
- */
- goto out;
next prev parent reply other threads:[~2023-12-13 18:14 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-12 23:25 [PATCH v2 bpf-next 00/10] Enhance BPF global subprogs with argument tags Andrii Nakryiko
2023-12-12 23:25 ` [PATCH v2 bpf-next 01/10] bpf: abstract away global subprog arg preparation logic from reg state setup Andrii Nakryiko
2023-12-12 23:25 ` [PATCH v2 bpf-next 02/10] bpf: reuse btf_prepare_func_args() check for main program BTF validation Andrii Nakryiko
2023-12-13 17:43 ` Eduard Zingerman
2023-12-13 18:06 ` Andrii Nakryiko
2023-12-13 18:14 ` Eduard Zingerman [this message]
2023-12-13 18:23 ` Andrii Nakryiko
2023-12-13 18:29 ` Eduard Zingerman
2023-12-12 23:25 ` [PATCH v2 bpf-next 03/10] bpf: prepare btf_prepare_func_args() for handling static subprogs Andrii Nakryiko
2023-12-12 23:25 ` [PATCH v2 bpf-next 04/10] bpf: move subprog call logic back to verifier.c Andrii Nakryiko
2023-12-12 23:25 ` [PATCH v2 bpf-next 05/10] bpf: reuse subprog argument parsing logic for subprog call checks Andrii Nakryiko
2023-12-12 23:25 ` [PATCH v2 bpf-next 06/10] bpf: support 'arg:xxx' btf_decl_tag-based hints for global subprog args Andrii Nakryiko
2023-12-13 17:43 ` Eduard Zingerman
2023-12-13 19:18 ` Andrii Nakryiko
2023-12-13 19:33 ` Eduard Zingerman
2023-12-12 23:25 ` [PATCH v2 bpf-next 07/10] bpf: add support for passing dynptr pointer to global subprog Andrii Nakryiko
2023-12-13 17:43 ` Eduard Zingerman
2023-12-12 23:25 ` [PATCH v2 bpf-next 08/10] libbpf: add __arg_xxx macros for annotating global func args Andrii Nakryiko
2023-12-13 17:43 ` Eduard Zingerman
2023-12-12 23:25 ` [PATCH v2 bpf-next 09/10] selftests/bpf: add global subprog annotation tests Andrii Nakryiko
2023-12-12 23:25 ` [PATCH v2 bpf-next 10/10] selftests/bpf: add freplace of BTF-unreliable main prog test Andrii Nakryiko
2023-12-13 17:44 ` Eduard Zingerman
2023-12-13 19:25 ` Andrii Nakryiko
2023-12-13 20:39 ` Eduard Zingerman
2023-12-13 22:48 ` Andrii Nakryiko
2023-12-14 0:14 ` Eduard Zingerman
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