From: peter enderborg <peter.enderborg@sony.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: "Thiébaud Weksteen" <tweek@google.com>,
"Paul Moore" <paul@paul-moore.com>,
"Nick Kralevich" <nnk@google.com>,
"Joel Fernandes" <joelaf@google.com>,
"Stephen Smalley" <stephen.smalley.work@gmail.com>,
"Eric Paris" <eparis@parisplace.org>,
"Ingo Molnar" <mingo@redhat.com>,
"Mauro Carvalho Chehab" <mchehab+huawei@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
"Rob Herring" <robh@kernel.org>,
linux-kernel@vger.kernel.org, selinux@vger.kernel.org
Subject: Re: [PATCH] RFC: selinux avc trace
Date: Thu, 30 Jul 2020 21:50:53 +0200 [thread overview]
Message-ID: <79e9971c-2a51-c180-d938-72932bd4d67d@sony.com> (raw)
In-Reply-To: <20200730152923.5101346c@oasis.local.home>
On 7/30/20 9:29 PM, Steven Rostedt wrote:
> On Thu, 30 Jul 2020 21:12:39 +0200
> peter enderborg <peter.enderborg@sony.com> wrote:
>
>>>> avc: denied { find } for interface=vendor.qti.hardware.perf::IPerf sid=u:r:permissioncontroller_app:s0:c230,c256,c512,c768 pid=9164 scontext=u:r:permissioncontroller_app:s0:c230,c256,c512,c768 tcontext=u:object_r:vendor_hal_perf_hwservice:s0 tclass=hwservice_manager permissive=0
>>>> avc: denied { execute } for pid=13914 comm="ScionFrontendAp" path="/data/user_de/0/com.google.android.gms/app_chimera/m/00000002/oat/arm64/DynamiteLoader.odex" dev="sda77" ino=204967 scontext=u:r:platform_app:s0:c512,c768 tcontext=u:object_r:privapp_data_file:s0:c512,c768 tclass=file permissive=0 ppid=788 pcomm="main" pgid=13914 pgcomm="on.updatecenter"
>>>>
>>>> It omit the fields that are not used. Some parts are common some are not. So a correct format specification for trace will be problematic if there is no "optional" field indicator.
>>> That's all quite noisy. What is the object of these changes? What
>>> exactly are you trying to trace and why?
>> It is noisy, and it have to be. it covers a lot of different areas. One common problem is
>> to debug userspace applications regarding violations. You get the violation from the logs
>> and try to figure out what you did to cause it. With a trace point you can do much better
>> when combine with other traces. Having a the userspace stack is a very good way,
>> unfortunately it does not work on that many architectures within trace.
>>
>> What exactly are you doing with any trace? You collect data to analyse what's
>> going on. This is not different. Selinux do a specific thing, but is has lots of parameters.
> Have you thought of adding multiple trace events with if statements
> around them to decode each specific type of event?
Yes. And I think class is good split point. But I think it will require
a few layers, but a is mostly data driven so I think it might be hard
to do it compile time. I think a hybrid might be possible,
but it then we need some ugly part with a other separator than =,
or some escape seq to separate.
sort of "generc1=X generic2=Y variable1^x variable2^y" or
"generc1=X generic2=Y leftover=[variable1=x variable2=y]"
If there was a formal parameter tree we could maybe do some
generated printer. I don't think there are one, maybe Paul Moore or Stephen Smalley
can verify that.
> Note, you can have a generic event that gets enabled by all the other
> events via the "reg" and "unreg" part of TRACE_EVENT_FN(). Say its
> called trace_avc, make a dummy trace_avc() call hat doesn't even need
> to be called anywhere, it just needs to exist to get to the other trace
> events.
>
> Then have:
>
> if (trace_avc_enabled()) {
> if (event1)
> trace_avc_req_event1();
> if (event2)
> trace_avc_req_event2();
> [..]
> }
>
> The reason for the trace_avc_enabled() is because that's a static
> branch, which is a nop when not enabled. When enabled, it is a jump to
> the out of band if condition block that has all the other trace events.
>
> -- Steve
next prev parent reply other threads:[~2020-07-30 19:50 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-24 9:15 [PATCH] selinux: add tracepoint on denials Thiébaud Weksteen
2020-07-24 13:32 ` Stephen Smalley
2020-07-24 13:54 ` Paul Moore
2020-07-28 12:49 ` Thiébaud Weksteen
2020-07-28 13:04 ` Stephen Smalley
2020-07-28 13:19 ` Thiébaud Weksteen
2020-07-28 13:12 ` Steven Rostedt
2020-07-28 13:23 ` Thiébaud Weksteen
2020-07-28 15:12 ` Paul Moore
2020-07-28 16:02 ` Thiébaud Weksteen
2020-07-28 16:19 ` Stephen Smalley
2020-07-28 16:20 ` Paul Moore
2020-07-30 15:50 ` Thiébaud Weksteen
2020-07-30 8:03 ` peter enderborg
2020-07-24 13:52 ` Steven Rostedt
2020-07-30 14:29 ` [PATCH] RFC: selinux avc trace peter enderborg
2020-07-30 14:50 ` Stephen Smalley
2020-07-30 15:47 ` peter enderborg
2020-07-30 15:04 ` Steven Rostedt
2020-07-30 15:31 ` peter enderborg
2020-07-30 16:02 ` Steven Rostedt
2020-07-30 17:05 ` peter enderborg
2020-07-30 17:16 ` Steven Rostedt
2020-07-30 19:12 ` peter enderborg
2020-07-30 19:29 ` Steven Rostedt
2020-07-30 19:50 ` peter enderborg [this message]
2020-07-31 11:07 ` Thiébaud Weksteen
2020-07-28 15:22 ` [PATCH] selinux: add tracepoint on denials Joel Fernandes
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