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From: Michael Schmitz <schmitzmic@gmail.com>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>,
	Linux/m68k <linux-m68k@vger.kernel.org>,
	Andreas Schwab <schwab@linux-m68k.org>
Subject: Re: [PATCH] m68k/kernel - wire up syscall_trace_enter/leave for m68k
Date: Thu, 27 Aug 2020 12:08:06 +1200
Message-ID: <855486ab-736a-19ad-35c2-174b5eb59898@gmail.com> (raw)
In-Reply-To: <CAMuHMdVNqgG_6LSSuzMZekE1q7i_V4YisDJQUsjptLDejNGaRw@mail.gmail.com>

Hi Geert,

On 26/08/20 11:23 PM, Geert Uytterhoeven wrote:
> Hi Michael,
>
> On Mon, Jul 27, 2020 at 6:19 AM Michael Schmitz <schmitzmic@gmail.com> wrote:
>> m68k (other than Coldfire) uses syscall_trace for both trace entry
>> and trace exit. Seccomp support requires separate entry points for
>> trace entry and exit which are already provided for Coldfire.
>>
>> Replace syscall_trace by syscall_trace_enter and syscall_trace_leave
>> in preparation for seccomp support. Check return code of
>> syscall_trace_enter(), and skip syscall if nonzero. Return code
>> will be left at what had been set by by ptrace or seccomp.
>>
>> No regression seen in testing with strace on ARAnyM.
>>
>> Signed-off-by: Michael Schmitz <schmitzmic@gmail.com>
> Thanks for your patch!
Thanks for looking into it!
>
>> Changes from RFC v1:
>>
>> - add return code check in do_trace_entry branch to enable syscall
>>    filtering (will return -EPERM)
>> - change to use testl for return code check (suggested by Andreas Schwab)
>>
>> Changes from RFC v2:
>>
>> - don't set return code of filtered syscall - seccomp may want to set
>>    that for use by calling process.
> As your email subject didn't contain "v3", b4[*] insists on picking up
> RFC v2, and refuses to pick up the latest version, even when forced

Argh - I thought that since the first two were tagged 'RFC', I could 
just restart with v1.

Never heard of b4, sorry.

> (msgid not present)...
>
> The patch itself looks good to me. Does it make sense to apply it before
> we have real seccomp support?

As far as I understand Adrian, it's needed as a prerequisite (though I 
admit there needs to be another patch adding the actual seccomp bits as 
well).

With my rather limited test setup, this was all I could test. I've done 
enough damage with 'I think this is how it should work' patches to add 
untested stuff.

In my not-at-all-humble opinion, the whole issue of whether to trigger a 
syscall abort on any non-zero return code, or just -1, is quite academic 
so I'd rather keep the broader non-zero test (unless someone points to a 
clear-cut reason why this is a Bad Thing).

Cheers,

     Michael


>
> [*] https://people.kernel.org/monsieuricon/introducing-b4-and-patch-attestation
>
> Gr{oetje,eeting}s,
>
>                          Geert
>

  parent reply index

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-23 10:03 syscall_trace_enter and syscall_trace_leave for m68k w/MMU John Paul Adrian Glaubitz
2020-07-23 22:56 ` Michael Schmitz
2020-07-25  1:48 ` [PATCH RFC] m68k/kernel - wire up syscall_trace_enter/leave for m68k Michael Schmitz
2020-07-26  1:28 ` [PATCH RFC v2] " Michael Schmitz
2020-07-27  4:19 ` [PATCH] " Michael Schmitz
2020-07-27 10:03   ` John Paul Adrian Glaubitz
2020-07-27 20:48     ` Michael Schmitz
2020-07-27 21:09       ` John Paul Adrian Glaubitz
2020-08-26 11:18         ` Geert Uytterhoeven
2020-08-26 11:50           ` John Paul Adrian Glaubitz
2020-08-26 11:23   ` Geert Uytterhoeven
2020-08-26 11:27     ` John Paul Adrian Glaubitz
2020-08-26 12:32       ` Geert Uytterhoeven
2020-08-26 12:35         ` John Paul Adrian Glaubitz
2020-08-26 12:38           ` Geert Uytterhoeven
2020-08-26 12:42             ` John Paul Adrian Glaubitz
2020-08-26 14:22               ` Geert Uytterhoeven
2020-08-27  0:08     ` Michael Schmitz [this message]
2020-08-27  9:19       ` Geert Uytterhoeven
2020-08-27 19:29         ` Michael Schmitz
2020-08-28  8:58           ` Geert Uytterhoeven
2020-08-05 12:23 ` syscall_trace_enter and syscall_trace_leave for m68k w/MMU Greg Ungerer
2020-08-05 12:36   ` John Paul Adrian Glaubitz

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