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, 10 Jan 2019 06:50:20 -0800
From:   Matthew Wilcox <>
To:     Dave Chinner <>
Cc:     Linus Torvalds <>,
        Jiri Kosina <>, Jann Horn <>,
        Andrew Morton <>,
        Greg KH <>,
        Peter Zijlstra <>,
        Michal Hocko <>, Linux-MM <>,
        kernel list <>,
        Linux API <>
Subject: Re: [PATCH] mm/mincore: allow for making sys_mincore() privileged

On Thu, Jan 10, 2019 at 11:44:24AM +1100, Dave Chinner wrote:
> And, really, this would be just another band-aid over a symptom of
> the information leak - it doesn't prevent users from being able to
> control page cache invalidation. It just removes one method, just
> like hacking mincore only removes one method of observing the page
> cache.  And, like mincore(), there's every chance it impacts on
> userspace in a negative manner and so we need to be very careful
> here.

Putting the mincore() / cache timing information leak aside though,
the current behaviour of XFS means that an attacker can screw up the
performance of random applications just by repeatedly doing O_DIRECT
reads of

Maybe O_DIRECT reads should be forbidden from files on XFS unless you
also have write access to them?  (eg owner).

Powered by blists - more mailing lists