From: KP Singh <kpsingh@chromium.org>
To: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: KP Singh <kpsingh@chromium.org>,
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: Thu, 5 Mar 2020 18:43:32 +0100 [thread overview]
Message-ID: <20200305174332.GA167686@google.com> (raw)
In-Reply-To: <20200304221729.d6omw6tltqhbw5xr@ast-mbp>
On 04-Mar 14:17, Alexei Starovoitov wrote:
> 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.
Thanks.
>
> I think it sets up a great base to parallelize further work.
Totally Agreed!
>
> 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
:) Sleepable BPF would indeed make it much simpler.
> 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 is quite important, especially for some of the examples we had
brought up.
I can take a look at the generalization of bpf_sk_storage.
Thanks!
- KP
> This work will be super useful for all bpf tracing too.
> Sleepable progs are useful for tracing as well.
prev parent reply other threads:[~2020-03-05 17:43 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 ` [PATCH bpf-next v4 0/7] Introduce BPF_MODIFY_RET tracing progs Alexei Starovoitov
2020-03-05 17:43 ` KP Singh [this message]
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