lkml.org 
[lkml]   [2010]   [Nov]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH v2] Restrict unprivileged access to kernel syslog
    On Tue, Nov 09, 2010 at 07:18:29PM -0500, Dan Rosenberg wrote:
    > The kernel syslog contains debugging information that is often useful
    > during exploitation of other vulnerabilities, such as kernel heap
    > addresses. Rather than futilely attempt to sanitize hundreds (or
    > thousands) of printk statements and simultaneously cripple useful
    > debugging functionality, it is far simpler to create an option that
    > prevents unprivileged users from reading the syslog.
    >
    > This patch, loosely based on grsecurity's GRKERNSEC_DMESG, creates the
    > dmesg_restrict sysctl. When set to "0", the default, no restrictions
    > are enforced. When set to "1", only users with CAP_SYS_ADMIN can read
    > the kernel syslog via dmesg(8) or other mechanisms.
    >
    > v2 adds CONFIG_SECURITY_RESTRICT_DMESG. When enabled, the default
    > sysctl value is set to "1". When disabled, the default sysctl value is
    > set to "0".
    >
    > Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com>
    > CC: Linus Torvalds <torvalds@linux-foundation.org>
    > CC: Ingo Molnar <mingo@elte.hu>
    > CC: Kees Cook <kees.cook@canonical.com>
    > CC: stable <stable@kernel.org>

    Acked-by: Kees Cook <kees.cook@canonical.com>

    As before, this looks fine and does the right thing with regard to /proc
    access to the kernel log.

    --
    Kees Cook
    Ubuntu Security Team


    \
     
     \ /
      Last update: 2010-11-10 17:35    [W:0.030 / U:241.444 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site