Thread (25 messages) 25 messages, 6 authors, 2018-07-12

[PATCH v5 2/8] kexec: add call to LSM hook in original kexec_load syscall

From: zohar@linux.ibm.com (Mimi Zohar)
Date: 2018-07-10 20:27:02
Also in: kexec, lkml

Hi Eric,

Can I get your Ack on this patch?

Mimi

On Mon, 2018-07-02 at 10:37 -0400, Mimi Zohar wrote:
quoted hunk ↗ jump to hunk
In order for LSMs and IMA-appraisal to differentiate between kexec_load
and kexec_file_load syscalls, both the original and new syscalls must
call an LSM hook.  This patch adds a call to security_kernel_load_data()
in the original kexec_load syscall.

Signed-off-by: Mimi Zohar <redacted>
Cc: Eric Biederman <redacted>
Cc: Luis R. Rodriguez <mcgrof@kernel.org>
Cc: Kees Cook <redacted>
Cc: David Howells <dhowells@redhat.com>
Acked-by: Serge Hallyn <serge@hallyn.com>
---
 kernel/kexec.c | 8 ++++++++
 1 file changed, 8 insertions(+)
diff --git a/kernel/kexec.c b/kernel/kexec.c
index aed8fb2564b3..68559808fdfa 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>
@@ -195,10 +196,17 @@ 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;

+	/* Permit LSMs and IMA to fail the kexec */
+	result = security_kernel_load_data(LOADING_KEXEC_IMAGE);
+	if (result < 0)
+		return result;
+
 	/*
 	 * Verify we have a legal set of flags
 	 * This leaves us room for future extensions.
--
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