From: Alexei Starovoitov <alexei.starovoitov@gmail.com>
To: KP Singh <kpsingh@chromium.org>
Cc: linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Paul Turner <pjt@google.com>, Jann Horn <jannh@google.com>,
Florent Revest <revest@chromium.org>,
Brendan Jackman <jackmanb@chromium.org>
Subject: Re: [PATCH bpf-next v4 0/7] Introduce BPF_MODIFY_RET tracing progs
Date: Wed, 4 Mar 2020 14:17:31 -0800 [thread overview]
Message-ID: <20200304221729.d6omw6tltqhbw5xr@ast-mbp> (raw)
In-Reply-To: <20200304191853.1529-1-kpsingh@chromium.org>
On Wed, Mar 04, 2020 at 08:18:46PM +0100, KP Singh wrote:
>
> Here is an example of how a fmod_ret program behaves:
>
> int func_to_be_attached(int a, int b)
V> { <--- do_fentry
>
> do_fmod_ret:
> <update ret by calling fmod_ret>
> if (ret != 0)
> goto do_fexit;
>
> original_function:
>
> <side_effects_happen_here>
>
> } <--- do_fexit
>
> ALLOW_ERROR_INJECTION(func_to_be_attached, ERRNO)
>
> The fmod_ret program attached to this function can be defined as:
>
> SEC("fmod_ret/func_to_be_attached")
> int BPF_PROG(func_name, int a, int b, int ret)
> {
> // This will skip the original function logic.
> return -1;
> }
Applied to bpf-next. Thanks.
I think it sets up a great base to parallelize further work.
1. I'm rebasing my sleepable BPF patches on top.
It's necessary to read enviroment variables without the
'opportunistic copy before hand' hack I saw in your github tree
to do bpf_get_env_var() helper.
2. please continue on LSM_HOOK patches to go via security tree.
3. we need a volunteer to generalize bpf_sk_storage to task and inode structs.
This work will be super useful for all bpf tracing too.
Sleepable progs are useful for tracing as well.
next prev parent reply other threads:[~2020-03-04 22:17 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-04 19:18 [PATCH bpf-next v4 0/7] Introduce BPF_MODIFY_RET tracing progs KP Singh
2020-03-04 19:18 ` [PATCH bpf-next v4 1/7] bpf: Refactor trampoline update code KP Singh
2020-03-04 19:18 ` [PATCH bpf-next v4 2/7] bpf: JIT helpers for fmod_ret progs KP Singh
2020-03-04 19:18 ` [PATCH bpf-next v4 3/7] bpf: Introduce BPF_MODIFY_RETURN KP Singh
2020-03-05 13:51 ` Stephen Smalley
2020-03-05 15:54 ` KP Singh
2020-03-05 17:35 ` Casey Schaufler
2020-03-05 18:03 ` Stephen Smalley
2020-03-05 18:47 ` Casey Schaufler
2020-03-05 19:43 ` Stephen Smalley
2020-03-05 21:16 ` KP Singh
2020-03-04 19:18 ` [PATCH bpf-next v4 4/7] bpf: Attachment verification for BPF_MODIFY_RETURN KP Singh
2020-03-05 13:43 ` Stephen Smalley
2020-03-05 17:21 ` Alexei Starovoitov
2020-03-04 19:18 ` [PATCH bpf-next v4 5/7] tools/libbpf: Add support " KP Singh
2020-03-04 19:18 ` [PATCH bpf-next v4 6/7] bpf: Add test ops for BPF_PROG_TYPE_TRACING KP Singh
2020-03-04 19:18 ` [PATCH bpf-next v4 7/7] bpf: Add selftests for BPF_MODIFY_RETURN KP Singh
2020-03-04 22:17 ` Alexei Starovoitov [this message]
2020-03-05 17:43 ` [PATCH bpf-next v4 0/7] Introduce BPF_MODIFY_RET tracing progs KP Singh
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