CRED: Wrap task credential accesses in the block loopback driver
David Howells [Thu, 13 Nov 2008 23:38:41 +0000 (10:38 +1100)]
Wrap access to task credentials so that they can be separated more easily from
the task_struct during the introduction of COW creds.

Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().

Change some task->e?[ug]id to task_e?[ug]id().  In some places it makes more
sense to use RCU directly rather than a convenient wrapper; these will be
addressed by later patches.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: James Morris <jmorris@namei.org>

drivers/block/loop.c

index 5c4ee70..fb06ed6 100644 (file)
@@ -936,8 +936,10 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
 {
        int err;
        struct loop_func_table *xfer;
+       uid_t uid = current_uid();
 
-       if (lo->lo_encrypt_key_size && lo->lo_key_owner != current->uid &&
+       if (lo->lo_encrypt_key_size &&
+           lo->lo_key_owner != uid &&
            !capable(CAP_SYS_ADMIN))
                return -EPERM;
        if (lo->lo_state != Lo_bound)
@@ -992,7 +994,7 @@ loop_set_status(struct loop_device *lo, const struct loop_info64 *info)
        if (info->lo_encrypt_key_size) {
                memcpy(lo->lo_encrypt_key, info->lo_encrypt_key,
                       info->lo_encrypt_key_size);
-               lo->lo_key_owner = current->uid;
+               lo->lo_key_owner = uid;
        }       
 
        return 0;