keys: distinguish per-uid keys in different namespaces

per-uid keys were looked by uid only.  Use the user namespace
to distinguish the same uid in different namespaces.

This does not address key_permission.  So a task can for instance
try to join a keyring owned by the same uid in another namespace.
That will be handled by a separate patch.

Signed-off-by: Serge E. Hallyn <serue@us.ibm.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 9 insertions, 2 deletions

diff --git a/security/keys/key.c b/security/keys/key.c
index f76c8a546fd3..4a1297d1ada4 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -18,6 +18,7 @@
 #include <linux/workqueue.h>
 #include <linux/random.h>
 #include <linux/err.h>
+#include <linux/user_namespace.h>
 #include "internal.h"
 
 static struct kmem_cache        *key_jar;
@@ -60,7 +61,7 @@ void __key_check(const struct key *key)
  * get the key quota record for a user, allocating a new record if one doesn't
  * already exist
  */
-struct key_user *key_user_lookup(uid_t uid)
+struct key_user *key_user_lookup(uid_t uid, struct user_namespace *user_ns)
 {
         struct key_user *candidate = NULL, *user;
         struct rb_node *parent = NULL;
@@ -79,6 +80,10 @@ struct key_user *key_user_lookup(uid_t uid)
                         p = &(*p)->rb_left;
                 else if (uid > user->uid)
                         p = &(*p)->rb_right;
+                else if (user_ns < user->user_ns)
+                        p = &(*p)->rb_left;
+                else if (user_ns > user->user_ns)
+                        p = &(*p)->rb_right;
                 else
                         goto found;
         }
@@ -106,6 +111,7 @@ struct key_user *key_user_lookup(uid_t uid)
         atomic_set(&candidate->nkeys, 0);
         atomic_set(&candidate->nikeys, 0);
         candidate->uid = uid;
+        candidate->user_ns = get_user_ns(user_ns);
         candidate->qnkeys = 0;
         candidate->qnbytes = 0;
         spin_lock_init(&candidate->lock);
@@ -136,6 +142,7 @@ void key_user_put(struct key_user *user)
         if (atomic_dec_and_lock(&user->usage, &key_user_lock)) {
                 rb_erase(&user->node, &key_user_tree);
                 spin_unlock(&key_user_lock);
+                put_user_ns(user->user_ns);
 
                 kfree(user);
         }
@@ -234,7 +241,7 @@ struct key *key_alloc(struct key_type *type, const char *desc,
         quotalen = desclen + type->def_datalen;
 
         /* get hold of the key tracking for this user */
-        user = key_user_lookup(uid);
+        user = key_user_lookup(uid, cred->user->user_ns);
         if (!user)
                 goto no_memory_1;