lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:   Tue, 26 Mar 2019 21:09:18 +0000
From:   Yuri Norov <>
To:     Andy Shevchenko <>,
        Yury Norov <>
CC:     Andrew Morton <>,
        Rasmus Villemoes <>,
        Arnd Bergmann <>,
        Kees Cook <>,
        Matthew Wilcox <>,
        Tetsuo Handa <>,
        "" <>,
        Mike Travis <>,
        Thomas Gleixner <>
Subject: Re: [PATCH 3/6] bitmap_parselist: rework input string parser

+ Mike Travis <>
+ Thomas Gleixner <>

On Tue, Mar 26, 2019 at 12:07:45AM +0300, Yury Norov wrote:
>> The requirement for this rework is to keep the __bitmap_parselist()
>> copy-less and single-pass but make it more readable and maintainable by
>> splitting into logical parts and removing explicit nested cycles and
>> opaque local variables.
>> __bitmap_parselist() can parse userspace inputs and therefore we cannot
>> use simple_strtoul() to parse numbers.

> So, all above depends to what memory we access kernel / user space.
> Perhaps we can get copy of memory of a given size and then parse it in kernel space always?

> --
> With Best Regards,
> Andy Shevchenko

What I missed during rework is that we have only one caller of *parselist_userĀ  -
it's write_irq_affinity() introduced by Mike Travis in kernel/irq/proc.c. It doesn't look
like a hot path as it's file operations handler. If no objections from Mike or Thomas,
I think it would make sense to copy_from_user() the userspace data at the beginning
in sake of simplicity of __bitmap_parselist(), as you suggested above.


Powered by blists - more mailing lists