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

Mimi Zohar
2018-04-12T22:42:14Z

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