[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>
diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index fc8e367..fc131d6 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -24,6 +24,7 @@
#include <linux/compiler.h>
struct file;
+struct completion;
#define CTL_MAXNAME 10 /* how many path components do we allow in a
call to sysctl? In other words, what is
@@ -925,6 +926,8 @@
{
ctl_table *ctl_table;
struct list_head ctl_entry;
+ int used;
+ struct completion *unregistering;
};
struct ctl_table_header * register_sysctl_table(ctl_table * table,