KEYS: Merge the type-specific data with the payload data

Merge the type-specific data with the payload data into one four-word chunk
as it seems pointless to keep them separate.

Use user_key_payload() for accessing the payloads of overloaded
user-defined keys.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-cifs@vger.kernel.org
cc: ecryptfs@vger.kernel.org
cc: linux-ext4@vger.kernel.org
cc: linux-f2fs-devel@lists.sourceforge.net
cc: linux-nfs@vger.kernel.org
cc: ceph-devel@vger.kernel.org
cc: linux-ima-devel@lists.sourceforge.net

1 files changed, 31 insertions, 16 deletions

diff --git a/security/keys/big_key.c b/security/keys/big_key.c
index b6adb94..907c152 100644
--- a/security/keys/big_key.c
+++ b/security/keys/big_key.c
@@ -21,6 +21,16 @@
 MODULE_LICENSE("GPL");
 
 /*
+ * Layout of key payload words.
+ */
+enum {
+	big_key_data,
+	big_key_path,
+	big_key_path_2nd_part,
+	big_key_len,
+};
+
+/*
  * If the data is under this limit, there's no point creating a shm file to
  * hold it as the permanently resident metadata for the shmem fs will be at
  * least as large as the data.
@@ -47,7 +57,7 @@ struct key_type key_type_big_key = {
  */
 int big_key_preparse(struct key_preparsed_payload *prep)
 {
-	struct path *path = (struct path *)&prep->payload;
+	struct path *path = (struct path *)&prep->payload.data[big_key_path];
 	struct file *file;
 	ssize_t written;
 	size_t datalen = prep->datalen;
@@ -60,7 +70,7 @@ int big_key_preparse(struct key_preparsed_payload *prep)
 	/* Set an arbitrary quota */
 	prep->quotalen = 16;
 
-	prep->type_data[1] = (void *)(unsigned long)datalen;
+	prep->payload.data[big_key_len] = (void *)(unsigned long)datalen;
 
 	if (datalen > BIG_KEY_FILE_THRESHOLD) {
 		/* Create a shmem file to store the data in.  This will permit the data
@@ -94,7 +104,8 @@ int big_key_preparse(struct key_preparsed_payload *prep)
 		if (!data)
 			return -ENOMEM;
 
-		prep->payload[0] = memcpy(data, prep->data, prep->datalen);
+		prep->payload.data[big_key_data] = data;
+		memcpy(data, prep->data, prep->datalen);
 	}
 	return 0;
 
@@ -110,10 +121,10 @@ error:
 void big_key_free_preparse(struct key_preparsed_payload *prep)
 {
 	if (prep->datalen > BIG_KEY_FILE_THRESHOLD) {
-		struct path *path = (struct path *)&prep->payload;
+		struct path *path = (struct path *)&prep->payload.data[big_key_path];
 		path_put(path);
 	} else {
-		kfree(prep->payload[0]);
+		kfree(prep->payload.data[big_key_data]);
 	}
 }
 
@@ -123,11 +134,12 @@ void big_key_free_preparse(struct key_preparsed_payload *prep)
  */
 void big_key_revoke(struct key *key)
 {
-	struct path *path = (struct path *)&key->payload.data2;
+	struct path *path = (struct path *)&key->payload.data[big_key_path];
 
 	/* clear the quota */
 	key_payload_reserve(key, 0);
-	if (key_is_instantiated(key) && key->type_data.x[1] > BIG_KEY_FILE_THRESHOLD)
+	if (key_is_instantiated(key) &&
+	    (size_t)key->payload.data[big_key_len] > BIG_KEY_FILE_THRESHOLD)
 		vfs_truncate(path, 0);
 }
 
@@ -136,14 +148,16 @@ void big_key_revoke(struct key *key)
  */
 void big_key_destroy(struct key *key)
 {
-	if (key->type_data.x[1] > BIG_KEY_FILE_THRESHOLD) {
-		struct path *path = (struct path *)&key->payload.data2;
+	size_t datalen = (size_t)key->payload.data[big_key_len];
+
+	if (datalen) {
+		struct path *path = (struct path *)&key->payload.data[big_key_path];
 		path_put(path);
 		path->mnt = NULL;
 		path->dentry = NULL;
 	} else {
-		kfree(key->payload.data);
-		key->payload.data = NULL;
+		kfree(key->payload.data[big_key_data]);
+		key->payload.data[big_key_data] = NULL;
 	}
 }
 
@@ -152,12 +166,12 @@ void big_key_destroy(struct key *key)
  */
 void big_key_describe(const struct key *key, struct seq_file *m)
 {
-	unsigned long datalen = key->type_data.x[1];
+	size_t datalen = (size_t)key->payload.data[big_key_len];
 
 	seq_puts(m, key->description);
 
 	if (key_is_instantiated(key))
-		seq_printf(m, ": %lu [%s]",
+		seq_printf(m, ": %zu [%s]",
 			   datalen,
 			   datalen > BIG_KEY_FILE_THRESHOLD ? "file" : "buff");
 }
@@ -168,14 +182,14 @@ void big_key_describe(const struct key *key, struct seq_file *m)
  */
 long big_key_read(const struct key *key, char __user *buffer, size_t buflen)
 {
-	unsigned long datalen = key->type_data.x[1];
+	size_t datalen = (size_t)key->payload.data[big_key_len];
 	long ret;
 
 	if (!buffer || buflen < datalen)
 		return datalen;
 
 	if (datalen > BIG_KEY_FILE_THRESHOLD) {
-		struct path *path = (struct path *)&key->payload.data2;
+		struct path *path = (struct path *)&key->payload.data[big_key_path];
 		struct file *file;
 		loff_t pos;
 
@@ -190,7 +204,8 @@ long big_key_read(const struct key *key, char __user *buffer, size_t buflen)
 			ret = -EIO;
 	} else {
 		ret = datalen;
-		if (copy_to_user(buffer, key->payload.data, datalen) != 0)
+		if (copy_to_user(buffer, key->payload.data[big_key_data],
+				 datalen) != 0)
 			ret = -EFAULT;
 	}