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  linux-cve-announce  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:   Thu, 7 Dec 2017 13:07:35 +0100
From:   Pavel Machek <>
To:     Michal Hocko <>
Cc:, Khalid Aziz <>,
        Michael Ellerman <>,
        Andrew Morton <>,
        Russell King - ARM Linux <>,
        Andrea Arcangeli <>,,
        LKML <>,,
        Florian Weimer <>,
        John Hubbard <>,
        Michal Hocko <>
Subject: Re: [PATCH 1/2] mm: introduce MAP_FIXED_SAFE


> MAP_FIXED is used quite often to enforce mapping at the particular
> range. The main problem of this flag is, however, that it is inherently
> dangerous because it unmaps existing mappings covered by the requested
> range. This can cause silent memory corruptions. Some of them even with
> serious security implications. While the current semantic might be
> really desiderable in many cases there are others which would want to
> enforce the given range but rather see a failure than a silent memory
> corruption on a clashing range. Please note that there is no guarantee
> that a given range is obeyed by the mmap even when it is free - e.g.
> arch specific code is allowed to apply an alignment.
> Introduce a new MAP_FIXED_SAFE flag for mmap to achieve this behavior.
> It has the same semantic as MAP_FIXED wrt. the given address request

Could we get some better name? Functionality seems reasonable, but
_SAFE suffix does not really explain what is going on to the user.



(cesky, pictures)

Powered by blists - more mailing lists