[PATCH] Fix sysctl unregistration oops (CVE-2005-2709)

You could open the /proc/sys/net/ipv4/conf/<if>/<whatever> file, then
wait for interface to go away, try to grab as much memory as possible in
hope to hit the (kfreed) ctl_table.  Then fill it with pointers to your
function.  Then do read from file you've opened and if you are lucky,
you'll get it called as ->proc_handler() in kernel mode.

So this is at least an Oops and possibly more.  It does depend on an
interface going away though, so less of a security risk than it would
otherwise be.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/proc_fs.h b/include/linux/proc_fs.h
index 65ceeaa30652..74488e49166d 100644
--- a/include/linux/proc_fs.h
+++ b/include/linux/proc_fs.h
@@ -66,6 +66,7 @@ struct proc_dir_entry {
         write_proc_t *write_proc;
         atomic_t count;         /* use count */
         int deleted;            /* delete flag */
+        void *set;
 };
 
 struct kcore_list {