From: "Mickaël Salaün" <mic@digikod.net>
To: Richard Weinberger <richard@nod.at>,
Tristan Schmelcher <tschmelcher@google.com>
Cc: linux-kernel@vger.kernel.org, Jeff Dike <jdike@addtoit.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
user-mode-linux-devel
<user-mode-linux-devel@lists.sourceforge.net>,
user-mode-linux-user@lists.sourceforge.net
Subject: Re: [PATCH v2 1/2] um: Set secure access mode for temporary file
Date: Thu, 10 Dec 2015 00:58:28 +0100 [thread overview]
Message-ID: <5668C024.2020803@digikod.net> (raw)
In-Reply-To: <56674F91.8050108@nod.at>
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On 08/12/2015 22:45, Richard Weinberger wrote:
> Am 08.12.2015 um 21:37 schrieb Tristan Schmelcher:
>> On 6 December 2015 at 09:43, Mickaël Salaün <mic@digikod.net> wrote:
>>> Well, I'm concerned to use umask because it is not thread-safe and drivers may use create_mem_file() in a multi-theaded context.
>>
>> You are right. We should perhaps set the umask to 0700 permanently
>> during process start. But I am not sure if this will interfere with
>> other UML code.
>
> It *should* not hurt. Let's see what explodes. :)
We can't force the kernel process umask without breaking compatibility with current implementation, especially with hostfs (i.e. the host umask prevail the guest one).
>>> I prefer to stick to fchmod and handle the race-condition with O_TMPFILE unsell someone is sure that this will not create bugs :)
>>
>> The fchmod call is basically useless and should probably be removed.
>
> I agree.
I propose then to simply remove the fchmod call and let the O_TMPFILE flag do the magic :)
Regards,
Mickaël
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next prev parent reply other threads:[~2015-12-09 23:58 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-29 14:03 [PATCH v2 0/2] um: Protect memory mapped file Mickaël Salaün
2015-11-29 14:03 ` [PATCH v2 1/2] um: Set secure access mode for temporary file Mickaël Salaün
2015-12-04 17:13 ` Tristan Schmelcher
2015-12-06 11:32 ` Mickaël Salaün
2015-12-06 11:57 ` Mickaël Salaün
2015-12-06 14:43 ` Mickaël Salaün
2015-12-08 20:37 ` Tristan Schmelcher
2015-12-08 21:45 ` [uml-devel] " Richard Weinberger
2015-12-09 23:58 ` Mickaël Salaün [this message]
2015-11-29 14:03 ` [PATCH v2 2/2] um: Use race-free temporary file creation Mickaël Salaün
2015-12-04 17:26 ` Tristan Schmelcher
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