vfs: define kernel_read_file_id enumeration

To differentiate between the kernel_read_file() callers, this patch
defines a new enumeration named kernel_read_file_id and includes the
caller identifier as an argument.

Subsequent patches define READING_KEXEC_IMAGE, READING_KEXEC_INITRAMFS,
READING_FIRMWARE, READING_MODULE, and READING_POLICY.

Changelog v3:
- Replace the IMA specific enumeration with a generic one.

Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: Kees Cook <keescook@chromium.org>
Acked-by: Luis R. Rodriguez <mcgrof@kernel.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 3 insertions, 1 deletions

diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
index f82631cc7248..2337f33913c1 100644
--- a/include/linux/lsm_hooks.h
+++ b/include/linux/lsm_hooks.h
@@ -567,6 +567,7 @@
  *      by the kernel.
  *      @buf pointer to buffer containing the file contents.
  *      @size length of the file contents.
+ *      @id kernel read file identifier
  *      Return 0 if permission is granted.
  * @task_fix_setuid:
  *      Update the module's state after setting one or more of the user
@@ -1464,7 +1465,8 @@ union security_list_options {
         int (*kernel_fw_from_file)(struct file *file, char *buf, size_t size);
         int (*kernel_module_request)(char *kmod_name);
         int (*kernel_module_from_file)(struct file *file);
-        int (*kernel_post_read_file)(struct file *file, char *buf, loff_t size);
+        int (*kernel_post_read_file)(struct file *file, char *buf, loff_t size,
+                                     enum kernel_read_file_id id);
         int (*task_fix_setuid)(struct cred *new, const struct cred *old,
                                 int flags);
         int (*task_setpgid)(struct task_struct *p, pid_t pgid);