[PATCH v3 2/7] kexec: add call to LSM hook in original kexec_load syscall

Mimi Zohar zohar at linux.vnet.ibm.com
Thu May 24 11:09:31 UTC 2018


In order for LSMs and IMA-appraisal to differentiate between the
original and new syscalls, both the original and new syscalls must call
an LSM hook.  This patch adds a call to security_kernel_read_data() in
the original kexec syscall.

Signed-off-by: Mimi Zohar <zohar at linux.vnet.ibm.com>
Cc: Eric Biederman <ebiederm at xmission.com>
Cc: Luis R. Rodriguez <mcgrof at kernel.org>
Cc: Kees Cook <keescook at chromium.org>
Cc: David Howells <dhowells at redhat.com>
---
 kernel/kexec.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/kernel/kexec.c b/kernel/kexec.c
index aed8fb2564b3..061ada41c18c 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_read_data(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

--
To unsubscribe from this list: send the line "unsubscribe linux-security-module" in
the body of a message to majordomo at vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html



More information about the Linux-security-module-archive mailing list