keys: make the keyring quotas controllable through /proc/sys

Make the keyring quotas controllable through /proc/sys files:

 (*) /proc/sys/kernel/keys/root_maxkeys
     /proc/sys/kernel/keys/root_maxbytes

     Maximum number of keys that root may have and the maximum total number of
     bytes of data that root may have stored in those keys.

 (*) /proc/sys/kernel/keys/maxkeys
     /proc/sys/kernel/keys/maxbytes

     Maximum number of keys that each non-root user may have and the maximum
     total number of bytes of data that each of those users may have stored in
     their keys.

Also increase the quotas as a number of people have been complaining that it's
not big enough.  I'm not sure that it's big enough now either, but on the
other hand, it can now be set in /etc/sysctl.conf.

Signed-off-by: David Howells <dhowells@redhat.com>
Cc: <kwc@citi.umich.edu>
Cc: <arunsr@cse.iitk.ac.in>
Cc: <dwalsh@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index fd3364827ccf..0a1d2733cf41 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -38,6 +38,7 @@
 #include <linux/writeback.h>
 #include <linux/hugetlb.h>
 #include <linux/initrd.h>
+#include <linux/key.h>
 #include <linux/times.h>
 #include <linux/limits.h>
 #include <linux/dcache.h>
@@ -809,6 +810,14 @@ static struct ctl_table kern_table[] = {
                 .proc_handler   = &proc_dostring,
                 .strategy       = &sysctl_string,
         },
+#ifdef CONFIG_KEYS
+        {
+                .ctl_name       = CTL_UNNUMBERED,
+                .procname       = "keys",
+                .mode           = 0555,
+                .child          = key_sysctls,
+        },
+#endif
 /*
  * NOTE: do not add new entries to this table unless you have read
  * Documentation/sysctl/ctl_unnumbered.txt