Messages in this thread | | | Date | Mon, 8 Nov 2010 21:34:40 -0800 | From | Kees Cook <> | Subject | Re: [PATCH] Restrict unprivileged access to kernel syslog |
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On Mon, Nov 08, 2010 at 10:28:58PM -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. > > Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com>
Acked-by: Kees Cook <kees.cook@canonical.com>
This looks good to me -- it leaves the /proc file access alone for priv-dropping ksyslogd implementations.
-Kees
-- Kees Cook Ubuntu Security Team
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