Messages in this thread | | | Date | Fri, 10 Dec 2010 16:11:51 -0800 | From | Kees Cook <> | Subject | Re: [PATCH v2] kptr_restrict for hiding kernel pointers from unprivileged users |
| |
On Fri, Dec 10, 2010 at 07:05:24PM -0500, Dan Rosenberg wrote: > The below patch adds the %pK format specifier, the > CONFIG_SECURITY_KPTR_RESTRICT configuration option, and the > kptr_restrict sysctl. > > The %pK format specifier is designed to hide exposed kernel pointers > from unprivileged users, specifically via /proc interfaces. Its > behavior depends on the kptr_restrict sysctl, whose default value > depends on CONFIG_SECURITY_KPTR_RESTRICT. If kptr_restrict is set to 0, > no deviation from the standard %p behavior occurs. If kptr_restrict is > set to 1, if the current user (intended to be a reader via seq_printf(), > etc.) does not have CAP_SYSLOG (which is currently in the LSM tree), > kernel pointers using %pK are printed as 0's. This was chosen over the > default "(null)", which cannot be parsed by userland %p, which expects > "(nil)". > > v2 improves checking for inappropriate context, on suggestion by Peter > Zijlstra. Thanks to Thomas Graf for suggesting use of a centralized > format specifier. > > Signed-off-by: Dan Rosenberg <drosenberg@vsecurity.com>
This will come in very handy! Thanks for working on this approach. :)
Acked-by: Kees Cook <kees.cook@canonical.com>
-Kees
-- Kees Cook Ubuntu Security Team
| |