KEYS: big_key: Use key preparsing

Make use of key preparsing in the big key type so that quota size determination
can take place prior to keyring locking when a key is being added.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Steve Dickson <steved@redhat.com>

1 files changed, 25 insertions, 16 deletions

diff --git a/security/keys/big_key.c b/security/keys/big_key.c
index 8137b27d641d..c2f91a0cf889 100644
--- a/security/keys/big_key.c
+++ b/security/keys/big_key.c
@@ -34,7 +34,9 @@ MODULE_LICENSE("GPL");
 struct key_type key_type_big_key = {
         .name                   = "big_key",
         .def_lookup_type        = KEYRING_SEARCH_LOOKUP_DIRECT,
-        .instantiate            = big_key_instantiate,
+        .preparse               = big_key_preparse,
+        .free_preparse          = big_key_free_preparse,
+        .instantiate            = generic_key_instantiate,
         .match                  = user_match,
         .revoke                 = big_key_revoke,
         .destroy                = big_key_destroy,
@@ -43,11 +45,11 @@ struct key_type key_type_big_key = {
 };
 
 /*
- * Instantiate a big key
+ * Preparse a big key
  */
-int big_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
+int big_key_preparse(struct key_preparsed_payload *prep)
 {
-        struct path *path = (struct path *)&key->payload.data2;
+        struct path *path = (struct path *)&prep->payload;
         struct file *file;
         ssize_t written;
         size_t datalen = prep->datalen;
@@ -58,11 +60,9 @@ int big_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
                 goto error;
 
         /* Set an arbitrary quota */
-        ret = key_payload_reserve(key, 16);
-        if (ret < 0)
-                goto error;
+        prep->quotalen = 16;
 
-        key->type_data.x[1] = datalen;
+        prep->type_data[1] = (void *)(unsigned long)datalen;
 
         if (datalen > BIG_KEY_FILE_THRESHOLD) {
                 /* Create a shmem file to store the data in.  This will permit the data
@@ -73,7 +73,7 @@ int big_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
                 file = shmem_kernel_file_setup("", datalen, 0);
                 if (IS_ERR(file)) {
                         ret = PTR_ERR(file);
-                        goto err_quota;
+                        goto error;
                 }
 
                 written = kernel_write(file, prep->data, prep->datalen, 0);
@@ -93,24 +93,33 @@ int big_key_instantiate(struct key *key, struct key_preparsed_payload *prep)
         } else {
                 /* Just store the data in a buffer */
                 void *data = kmalloc(datalen, GFP_KERNEL);
-                if (!data) {
-                        ret = -ENOMEM;
-                        goto err_quota;
-                }
+                if (!data)
+                        return -ENOMEM;
 
-                key->payload.data = memcpy(data, prep->data, prep->datalen);
+                prep->payload[0] = memcpy(data, prep->data, prep->datalen);
         }
         return 0;
 
 err_fput:
         fput(file);
-err_quota:
-        key_payload_reserve(key, 0);
 error:
         return ret;
 }
 
 /*
+ * Clear preparsement.
+ */
+void big_key_free_preparse(struct key_preparsed_payload *prep)
+{
+        if (prep->datalen > BIG_KEY_FILE_THRESHOLD) {
+                struct path *path = (struct path *)&prep->payload;
+                path_put(path);
+        } else {
+                kfree(prep->payload[0]);
+        }
+}
+
+/*
  * dispose of the links from a revoked keyring
  * - called with the key sem write-locked
  */