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, 10 insertions, 4 deletions

diff --git a/security/keys/internal.h b/security/keys/internal.h
index 2ab38854c47..8c05587f501 100644
--- a/security/keys/internal.h
+++ b/security/keys/internal.h
@@ -57,10 +57,6 @@ struct key_user {
         int                     qnbytes;        /* number of bytes allocated to this user */
 };
 
-#define KEYQUOTA_MAX_KEYS       100
-#define KEYQUOTA_MAX_BYTES      10000
-#define KEYQUOTA_LINK_BYTES     4               /* a link in a keyring is worth 4 bytes */
-
 extern struct rb_root   key_user_tree;
 extern spinlock_t       key_user_lock;
 extern struct key_user  root_key_user;
@@ -68,6 +64,16 @@ extern struct key_user	root_key_user;
 extern struct key_user *key_user_lookup(uid_t uid);
 extern void key_user_put(struct key_user *user);
 
+/*
+ * key quota limits
+ * - root has its own separate limits to everyone else
+ */
+extern unsigned key_quota_root_maxkeys;
+extern unsigned key_quota_root_maxbytes;
+extern unsigned key_quota_maxkeys;
+extern unsigned key_quota_maxbytes;
+
+#define KEYQUOTA_LINK_BYTES     4               /* a link in a keyring is worth 4 bytes */
 
 
 extern struct rb_root key_serial_tree;