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, 6 insertions, 3 deletions

diff --git a/security/keys/proc.c b/security/keys/proc.c
index e54679b848cf..f619170da760 100644
--- a/security/keys/proc.c
+++ b/security/keys/proc.c
@@ -242,6 +242,10 @@ static int proc_key_users_show(struct seq_file *m, void *v)
 {
         struct rb_node *_p = v;
         struct key_user *user = rb_entry(_p, struct key_user, node);
+        unsigned maxkeys = (user->uid == 0) ?
+                key_quota_root_maxkeys : key_quota_maxkeys;
+        unsigned maxbytes = (user->uid == 0) ?
+                key_quota_root_maxbytes : key_quota_maxbytes;
 
         seq_printf(m, "%5u: %5d %d/%d %d/%d %d/%d\n",
                    user->uid,
@@ -249,10 +253,9 @@ static int proc_key_users_show(struct seq_file *m, void *v)
                    atomic_read(&user->nkeys),
                    atomic_read(&user->nikeys),
                    user->qnkeys,
-                   KEYQUOTA_MAX_KEYS,
+                   maxkeys,
                    user->qnbytes,
-                   KEYQUOTA_MAX_BYTES
-                   );
+                   maxbytes);
 
         return 0;