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From: Russell King - ARM Linux <linux@arm.linux.org.uk>
To: AKASHI Takahiro <takahiro.akashi@linaro.org>
Cc: Will Deacon <will.deacon@arm.com>,
	"linaro-kernel@lists.linaro.org" <linaro-kernel@lists.linaro.org>,
	Kees Cook <keescook@chromium.org>,
	Catalin Marinas <Catalin.Marinas@arm.com>,
	"arndb@arndb.de" <arndb@arndb.de>,
	LKML <linux-kernel@vger.kernel.org>,
	Deepak Saxena <dsaxena@linaro.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v6 2/6] arm64: ptrace: allow tracer to skip a system call
Date: Mon, 1 Sep 2014 12:47:51 +0100	[thread overview]
Message-ID: <20140901114751.GG30401@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <53FD72E2.4020103@linaro.org>

On Wed, Aug 27, 2014 at 02:55:46PM +0900, AKASHI Takahiro wrote:
> 1)
> setting x0 to -ENOSYS is necessary because, otherwise, user-issued syscall(-1) will
> return a bogus value when audit tracing is on.
>
> Please note that, on arm,
>                  not traced      traced
>                  ------          ------
> syscall(-1)      aborted         OOPs(BUG_ON)
> syscall(-3000)   aborted         aborted
> syscall(1000)    ENOSYS          ENOSYS

Two points here:

1. You've found a case which causes a BUG_ON().  Where is the bug report
   for this, so the problem can be investigated and resolved?

2. What do you mean by "aborted" ?

Please, if you find a problem with 32-bit ARM, report it.  Don't hide it,
because hiding it can be a security issue or in the case of BUG_ON(), it
could be a denial of service issue.

As you're part of Linaro, I would have thought you'd be more responsible
in this regard - after all, Linaro is supposed to be about improving the
ARM kernel...  Maybe I got that wrong, and Linaro is actually about
ensuring that the ARM kernel is stuffed full of broken features?

-- 
FTTC broadband for 0.8mile line: currently at 9.5Mbps down 400kbps up
according to speedtest.net.

WARNING: multiple messages have this Message-ID (diff)
From: linux@arm.linux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v6 2/6] arm64: ptrace: allow tracer to skip a system call
Date: Mon, 1 Sep 2014 12:47:51 +0100	[thread overview]
Message-ID: <20140901114751.GG30401@n2100.arm.linux.org.uk> (raw)
In-Reply-To: <53FD72E2.4020103@linaro.org>

On Wed, Aug 27, 2014 at 02:55:46PM +0900, AKASHI Takahiro wrote:
> 1)
> setting x0 to -ENOSYS is necessary because, otherwise, user-issued syscall(-1) will
> return a bogus value when audit tracing is on.
>
> Please note that, on arm,
>                  not traced      traced
>                  ------          ------
> syscall(-1)      aborted         OOPs(BUG_ON)
> syscall(-3000)   aborted         aborted
> syscall(1000)    ENOSYS          ENOSYS

Two points here:

1. You've found a case which causes a BUG_ON().  Where is the bug report
   for this, so the problem can be investigated and resolved?

2. What do you mean by "aborted" ?

Please, if you find a problem with 32-bit ARM, report it.  Don't hide it,
because hiding it can be a security issue or in the case of BUG_ON(), it
could be a denial of service issue.

As you're part of Linaro, I would have thought you'd be more responsible
in this regard - after all, Linaro is supposed to be about improving the
ARM kernel...  Maybe I got that wrong, and Linaro is actually about
ensuring that the ARM kernel is stuffed full of broken features?

-- 
FTTC broadband for 0.8mile line: currently at 9.5Mbps down 400kbps up
according to speedtest.net.

  parent reply	other threads:[~2014-09-01 11:48 UTC|newest]

Thread overview: 72+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-08-21  8:56 [PATCH v6 0/6] arm64: add seccomp support AKASHI Takahiro
2014-08-21  8:56 ` AKASHI Takahiro
2014-08-21  8:56 ` [PATCH v6 1/6] arm64: ptrace: add PTRACE_SET_SYSCALL AKASHI Takahiro
2014-08-21  8:56   ` AKASHI Takahiro
2014-08-21 16:47   ` Kees Cook
2014-08-21 16:47     ` Kees Cook
2014-08-22  0:19     ` AKASHI Takahiro
2014-08-22  0:19       ` AKASHI Takahiro
2014-08-26 17:46       ` Will Deacon
2014-08-26 17:46         ` Will Deacon
2014-08-27  5:32         ` AKASHI Takahiro
2014-08-27  5:32           ` AKASHI Takahiro
2014-09-03 18:34           ` Kees Cook
2014-09-03 18:34             ` Kees Cook
2014-08-21  8:56 ` [PATCH v6 2/6] arm64: ptrace: allow tracer to skip a system call AKASHI Takahiro
2014-08-21  8:56   ` AKASHI Takahiro
2014-08-21 17:08   ` Kees Cook
2014-08-21 17:08     ` Kees Cook
2014-08-22  0:35     ` AKASHI Takahiro
2014-08-22  0:35       ` AKASHI Takahiro
2014-08-26 17:51       ` Will Deacon
2014-08-26 17:51         ` Will Deacon
2014-08-27  5:55         ` AKASHI Takahiro
2014-08-27  5:55           ` AKASHI Takahiro
2014-09-01 11:37           ` Will Deacon
2014-09-01 11:37             ` Will Deacon
2014-09-02  7:58             ` AKASHI Takahiro
2014-09-02  7:58               ` AKASHI Takahiro
2014-09-01 11:47           ` Russell King - ARM Linux [this message]
2014-09-01 11:47             ` Russell King - ARM Linux
2014-09-02  8:47             ` AKASHI Takahiro
2014-09-02  8:47               ` AKASHI Takahiro
2014-09-02  9:16               ` Russell King - ARM Linux
2014-09-02  9:16                 ` Russell King - ARM Linux
2014-09-02  9:31                 ` Russell King - ARM Linux
2014-09-02  9:31                   ` Russell King - ARM Linux
2014-09-05 10:08                 ` AKASHI Takahiro
2014-09-05 10:08                   ` AKASHI Takahiro
2014-10-01 11:08         ` AKASHI Takahiro
2014-10-01 11:08           ` AKASHI Takahiro
2014-10-03 15:23           ` Will Deacon
2014-10-03 15:23             ` Will Deacon
2014-10-06  8:04             ` AKASHI Takahiro
2014-10-06  8:04               ` AKASHI Takahiro
2014-08-21  8:56 ` [PATCH v6 3/6] asm-generic: add generic seccomp.h for secure computing mode 1 AKASHI Takahiro
2014-08-21  8:56   ` AKASHI Takahiro
2014-08-21 17:51   ` Kees Cook
2014-08-21 17:51     ` Kees Cook
2014-08-22  0:38     ` AKASHI Takahiro
2014-08-22  0:38       ` AKASHI Takahiro
2014-08-21  8:56 ` [PATCH v6 4/6] arm64: add seccomp syscall for compat task AKASHI Takahiro
2014-08-21  8:56   ` AKASHI Takahiro
2014-08-21 17:52   ` Kees Cook
2014-08-21 17:52     ` Kees Cook
2014-08-22  0:39     ` AKASHI Takahiro
2014-08-22  0:39       ` AKASHI Takahiro
2014-08-26 17:53   ` Will Deacon
2014-08-26 17:53     ` Will Deacon
2014-08-27  5:57     ` AKASHI Takahiro
2014-08-27  5:57       ` AKASHI Takahiro
2014-08-21  8:56 ` [PATCH v6 5/6] arm64: add SIGSYS siginfo " AKASHI Takahiro
2014-08-21  8:56   ` AKASHI Takahiro
2014-08-21 17:54   ` Kees Cook
2014-08-21 17:54     ` Kees Cook
2014-08-22  0:44     ` AKASHI Takahiro
2014-08-22  0:44       ` AKASHI Takahiro
2014-08-26 17:55   ` Will Deacon
2014-08-26 17:55     ` Will Deacon
2014-08-27  5:58     ` AKASHI Takahiro
2014-08-27  5:58       ` AKASHI Takahiro
2014-08-21  8:56 ` [PATCH v6 6/6] arm64: add seccomp support AKASHI Takahiro
2014-08-21  8:56   ` AKASHI Takahiro

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