linux-arm-kernel.lists.infradead.org archive mirror
 help / color / mirror / Atom feed
From: takahiro.akashi@linaro.org (AKASHI Takahiro)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v5 3/3] arm64: Add seccomp support
Date: Tue, 12 Aug 2014 15:57:25 +0900	[thread overview]
Message-ID: <53E9BAD5.3080201@linaro.org> (raw)
In-Reply-To: <20140811092409.GE15344@arm.com>

Will,

On 08/11/2014 06:24 PM, Will Deacon wrote:
> On Fri, Aug 08, 2014 at 08:35:42AM +0100, AKASHI Takahiro wrote:
>> On 08/06/2014 12:08 AM, Kees Cook wrote:
>>> On Fri, Jul 25, 2014 at 2:37 AM, AKASHI Takahiro
>>> <takahiro.akashi@linaro.org> wrote:
>>>> I found a bug in my current patch (v5). When 32-bit tracer skips a system call,
>>>> we should not update syscallno from x8 since syscallno is re-written directly
>>>> via ptrace(PTRACE_SET_SYSCALL).
>>>
>>> Ah, yes. Will aarch64 have a PTRACE_SET_SYSCALL option, or is this
>>> strictly a 32-bit vs 64-bit issue?
>>
>> As discussed in a few weeks ago, aarch64 won't support PTRACE_SET_SYSCALL.
>
> Well, I don't think anything was set in stone. If you have a compelling
> reason why adding the new request gives you something over setting w8
> directly, then we can extend ptrace.

Yeah, I think I may have to change my mind. Looking into __secure_computing(),
I found the code below:

 >     case SECCOMP_MODE_FILTER:
 >         case SECCOMP_RET_TRACE:
 >             ...
 >             if (syscall_get_nr(current, regs) < 0)
 >                 goto skip;

This implies that we should modify syscallno *before* __secure_computing() returns.

I assumed, in my next version, we could skip a system call by overwriting syscallno
with x8 in syscall_trace_enter() after __secure_computing() returns 0, and it actually
works.
But we'd better implement PTRACE_SET_SYSCALL to comply with what __secure_computing()
expects.

-Takahiro AKASHI


> Will
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>

  reply	other threads:[~2014-08-12  6:57 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-22  9:14 [PATCH v5 0/3] arm64: Add seccomp support AKASHI Takahiro
2014-07-22  9:14 ` [PATCH v5 1/3] arm64: ptrace: reload a syscall number after ptrace operations AKASHI Takahiro
2014-07-22 20:15   ` Kees Cook
2014-07-23  7:03     ` AKASHI Takahiro
2014-07-23  8:25       ` Will Deacon
2014-07-23  9:09         ` AKASHI Takahiro
2014-07-23 15:13       ` Kees Cook
2014-07-24  3:54   ` Andy Lutomirski
2014-07-24  5:57     ` AKASHI Takahiro
2014-07-24 15:01       ` Andy Lutomirski
2014-07-25 10:36         ` AKASHI Takahiro
2014-07-25 11:03           ` Will Deacon
2014-07-29  6:49             ` AKASHI Takahiro
2014-07-29 13:26               ` Will Deacon
2014-07-22  9:14 ` [PATCH v5 2/3] asm-generic: Add generic seccomp.h for secure computing mode 1 AKASHI Takahiro
2014-07-24  3:40   ` Andy Lutomirski
2014-07-24  4:41     ` Kees Cook
2014-07-24  5:17       ` AKASHI Takahiro
2014-07-24 14:57         ` Andy Lutomirski
2014-07-25  8:52           ` AKASHI Takahiro
2014-07-22  9:14 ` [PATCH v5 3/3] arm64: Add seccomp support AKASHI Takahiro
2014-07-24  3:52   ` Andy Lutomirski
2014-07-24  5:40     ` AKASHI Takahiro
2014-07-24 15:00       ` Andy Lutomirski
2014-07-24 15:16         ` Catalin Marinas
2014-07-25  9:37         ` AKASHI Takahiro
2014-08-05 15:08           ` Kees Cook
2014-08-08  7:35             ` AKASHI Takahiro
2014-08-11  9:24               ` Will Deacon
2014-08-12  6:57                 ` AKASHI Takahiro [this message]
2014-08-12  9:40                   ` Will Deacon
2014-08-12 11:17                     ` AKASHI Takahiro
2014-08-15 14:33                       ` Will Deacon
2014-07-22 20:16 ` [PATCH v5 0/3] " Kees Cook
2014-07-23  7:09   ` AKASHI Takahiro
2014-07-23 15:36     ` Kees Cook

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=53E9BAD5.3080201@linaro.org \
    --to=takahiro.akashi@linaro.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).