[PATCH] keys: sort out key quota system

Add the ability for key creation to overrun the user's quota in some
circumstances - notably when a session keyring is created and assigned to a
process that didn't previously have one.

This means it's still possible to log in, should PAM require the creation of a
new session keyring, and fix an overburdened key quota.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 14 insertions, 12 deletions

diff --git a/security/keys/key.c b/security/keys/key.c
index 51f851557389..3601fddca9f2 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -248,7 +248,7 @@ static inline void key_alloc_serial(struct key *key)
  */
 struct key *key_alloc(struct key_type *type, const char *desc,
                       uid_t uid, gid_t gid, struct task_struct *ctx,
-                      key_perm_t perm, int not_in_quota)
+                      key_perm_t perm, unsigned long flags)
 {
         struct key_user *user = NULL;
         struct key *key;
@@ -269,12 +269,14 @@ struct key *key_alloc(struct key_type *type, const char *desc,
 
         /* check that the user's quota permits allocation of another key and
          * its description */
-        if (!not_in_quota) {
+        if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
                 spin_lock(&user->lock);
-                if (user->qnkeys + 1 >= KEYQUOTA_MAX_KEYS ||
-                    user->qnbytes + quotalen >= KEYQUOTA_MAX_BYTES
-                    )
-                        goto no_quota;
+                if (!(flags & KEY_ALLOC_QUOTA_OVERRUN)) {
+                        if (user->qnkeys + 1 >= KEYQUOTA_MAX_KEYS ||
+                            user->qnbytes + quotalen >= KEYQUOTA_MAX_BYTES
+                            )
+                                goto no_quota;
+                }
 
                 user->qnkeys++;
                 user->qnbytes += quotalen;
@@ -308,7 +310,7 @@ struct key *key_alloc(struct key_type *type, const char *desc,
         key->payload.data = NULL;
         key->security = NULL;
 
-        if (!not_in_quota)
+        if (!(flags & KEY_ALLOC_NOT_IN_QUOTA))
                 key->flags |= 1 << KEY_FLAG_IN_QUOTA;
 
         memset(&key->type_data, 0, sizeof(key->type_data));
@@ -318,7 +320,7 @@ struct key *key_alloc(struct key_type *type, const char *desc,
 #endif
 
         /* let the security module know about the key */
-        ret = security_key_alloc(key, ctx);
+        ret = security_key_alloc(key, ctx, flags);
         if (ret < 0)
                 goto security_error;
 
@@ -332,7 +334,7 @@ error:
 security_error:
         kfree(key->description);
         kmem_cache_free(key_jar, key);
-        if (!not_in_quota) {
+        if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
                 spin_lock(&user->lock);
                 user->qnkeys--;
                 user->qnbytes -= quotalen;
@@ -345,7 +347,7 @@ security_error:
 no_memory_3:
         kmem_cache_free(key_jar, key);
 no_memory_2:
-        if (!not_in_quota) {
+        if (!(flags & KEY_ALLOC_NOT_IN_QUOTA)) {
                 spin_lock(&user->lock);
                 user->qnkeys--;
                 user->qnbytes -= quotalen;
@@ -761,7 +763,7 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref,
                                const char *description,
                                const void *payload,
                                size_t plen,
-                               int not_in_quota)
+                               unsigned long flags)
 {
         struct key_type *ktype;
         struct key *keyring, *key = NULL;
@@ -822,7 +824,7 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref,
 
         /* allocate a new key */
         key = key_alloc(ktype, description, current->fsuid, current->fsgid,
-                        current, perm, not_in_quota);
+                        current, perm, flags);
         if (IS_ERR(key)) {
                 key_ref = ERR_PTR(PTR_ERR(key));
                 goto error_3;