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    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 <>
    > CC: Linus Torvalds <>
    > CC: Ingo Molnar <>
    > CC: Kees Cook <>
    > CC: stable <>

    Acked-by: Kees Cook <>

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

    Kees Cook
    Ubuntu Security Team

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      Last update: 2010-11-10 17:35    [W:0.178 / U:2.184 seconds]
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