integrity: provide a hook to load keys when rootfs is ready

Keys can only be loaded once the rootfs is mounted. Initcalls
are not suitable for that. This patch defines a special hook
to load the x509 public keys onto the IMA keyring, before
attempting to access any file. The keys are required for
verifying the file's signature. The hook is called after the
root filesystem is mounted and before the kernel calls 'init'.

Changes in v3:
* added more explanation to the patch description (Mimi)

Changes in v2:
* Hook renamed as 'integrity_load_keys()' to handle both IMA and EVM
  keys by integrity subsystem.
* Hook patch moved after defining loading functions

Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/init/main.c b/init/main.c
index e8ae1fef0908..2c1928d08b78 100644
--- a/init/main.c
+++ b/init/main.c
@@ -78,6 +78,7 @@
 #include <linux/context_tracking.h>
 #include <linux/random.h>
 #include <linux/list.h>
+#include <linux/integrity.h>
 
 #include <asm/io.h>
 #include <asm/bugs.h>
@@ -1026,8 +1027,11 @@ static noinline void __init kernel_init_freeable(void)
          * Ok, we have completed the initial bootup, and
          * we're essentially up and running. Get rid of the
          * initmem segments and start the user-mode stuff..
+         *
+         * rootfs is available now, try loading the public keys
+         * and default modules
          */
 
-        /* rootfs is available now, try loading default modules */
+        integrity_load_keys();
         load_default_modules();
 }