[PATCH 2/3] kexec: call LSM hook for kexec_load syscall

[Mimi Zohar <zohar@linux.vnet.ibm.com>]

Allow LSMs and IMA to differentiate between the kexec_load and
kexec_file_load syscalls by adding an "unnecessary" call to
security_kernel_read_file() in kexec_load.  This would be similar to the
existing init_module syscall calling security_kernel_read_file().

Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
---
 kernel/kexec.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/kernel/kexec.c b/kernel/kexec.c
index aed8fb2564b3..d1386cfc6796 100644
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -11,6 +11,7 @@
 #include <linux/capability.h>
 #include <linux/mm.h>
 #include <linux/file.h>
+#include <linux/security.h>
 #include <linux/kexec.h>
 #include <linux/mutex.h>
 #include <linux/list.h>
@@ -195,11 +196,21 @@ static int do_kexec_load(unsigned long entry, unsigned long nr_segments,
 static inline int kexec_load_check(unsigned long nr_segments,
 				   unsigned long flags)
 {
+	int result;
+
 	/* We only trust the superuser with rebooting the system. */
 	if (!capable(CAP_SYS_BOOT) || kexec_load_disabled)
 		return -EPERM;
 
 	/*
+	 * Allow LSMs and IMA to differentiate between kexec_load and
+	 * kexec_file_load syscalls.
+	 */
+	result = security_kernel_read_file(NULL, READING_KEXEC_IMAGE);
+	if (result < 0)
+		return result;
+
+	/*
 	 * Verify we have a legal set of flags
 	 * This leaves us room for future extensions.
 	 */
-- 
2.7.5