Re: [PATCH v4] kernel: add kcov code coverage

From	Dmitry Vyukov <dvyukov@google.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v4] kernel: add kcov code coverage
Date	2016-01-19 15:10 +0100
Message-ID	<qSF8S-w0-17@gated-at.bofh.it> (permalink)
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On Tue, Jan 19, 2016 at 2:05 PM, Kirill A. Shutemov
<kirill@shutemov.name> wrote:
> On Tue, Jan 19, 2016 at 01:55:43PM +0100, Dmitry Vyukov wrote:
>> >> +static int __init kcov_init(void)
>> >> +{
>> >> +     if (!debugfs_create_file("kcov", 0666, NULL, NULL, &kcov_fops)) {
>> >
>> > Why 0666? May be 0600?.
>>
>> The idea is that it can be useful to fuzz-test under a normal user as well.
>> This file is also guarded by debugfs mount permissions. Usually it is mounted
>> as 0700, so normal users can't get access to it.
>> However if one wants to fuzz-test under a normal user, he could mount
>> debugfs as 0777 and get access to this file.
>>
>> I am not very strong about this, though. If you say, I will change it to 0600.
>> I open this file as root at the moment. And we can change it back
>> if/when we better understand a potential use case.
>
> I think it's safer to make it 0600. It's up to system administrator to
> change permissions, if he wants give this capability to mortals.

Great! I've missed the possibility of chmoding it afterwards. Will
change to 0600 in next version.

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[PATCH v4] kernel: add kcov code coverage Dmitry Vyukov <dvyukov@google.com> - 2016-01-18 20:30 +0100
  Re: [PATCH v4] kernel: add kcov code coverage "Kirill A. Shutemov" <kirill@shutemov.name> - 2016-01-19 00:00 +0100
    Re: [PATCH v4] kernel: add kcov code coverage Dmitry Vyukov <dvyukov@google.com> - 2016-01-19 14:00 +0100
      Re: [PATCH v4] kernel: add kcov code coverage "Kirill A. Shutemov" <kirill@shutemov.name> - 2016-01-19 14:10 +0100
        Re: [PATCH v4] kernel: add kcov code coverage Dmitry Vyukov <dvyukov@google.com> - 2016-01-19 15:10 +0100

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