integrity: define a new function integrity_read_file()

This patch defines a new function called integrity_read_file()
to read file from the kernel into a buffer. Subsequent patches
will read a file containing the public keys and load them onto
the IMA keyring.

This patch moves and renames ima_kernel_read(), the non-security
checking version of kernel_read(), to integrity_kernel_read().

Changes in v3:
* Patch descriptions improved (Mimi)
* Add missing cast (kbuild test robot)

Changes in v2:
* configuration option removed
* function declared as '__init'

Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
diff --git a/security/integrity/integrity.h b/security/integrity/integrity.h
index f51ad65..20d2204 100644
--- a/security/integrity/integrity.h
+++ b/security/integrity/integrity.h
@@ -119,6 +119,10 @@
  */
 struct integrity_iint_cache *integrity_iint_find(struct inode *inode);
 
+int integrity_kernel_read(struct file *file, loff_t offset,
+			  char *addr, unsigned long count);
+int __init integrity_read_file(const char *path, char **data);
+
 #define INTEGRITY_KEYRING_EVM		0
 #define INTEGRITY_KEYRING_MODULE	1
 #define INTEGRITY_KEYRING_IMA		2