kernel/s390-Lock-down-the-kernel-when-the-IPL-secure-flag-i.patch

From eaa12998810bd9db85dec71f0da55fd5aae73d0f Mon Sep 17 00:00:00 2001
From: Jeremy Cline <jcline@redhat.com>
Date: Wed, 30 Oct 2019 14:37:49 +0000
Subject: [PATCH] s390: Lock down the kernel when the IPL secure flag is set

Automatically lock down the kernel to LOCKDOWN_INTEGRITY_MAX if
the IPL secure flag is set.

Suggested-by: Philipp Rudo <prudo@redhat.com>
Signed-off-by: Jeremy Cline <jcline@redhat.com>
---
 arch/s390/include/asm/ipl.h | 1 +
 arch/s390/kernel/ipl.c      | 5 +++++
 arch/s390/kernel/setup.c    | 4 ++++
 3 files changed, 10 insertions(+)

diff --git a/arch/s390/include/asm/ipl.h b/arch/s390/include/asm/ipl.h
index 084e71b7272a..1d1b5ec7357b 100644
--- a/arch/s390/include/asm/ipl.h
+++ b/arch/s390/include/asm/ipl.h
@@ -109,6 +109,7 @@ int ipl_report_add_component(struct ipl_report *report, struct kexec_buf *kbuf,
 			     unsigned char flags, unsigned short cert);
 int ipl_report_add_certificate(struct ipl_report *report, void *key,
 			       unsigned long addr, unsigned long len);
+bool ipl_get_secureboot(void);
 
 /*
  * DIAG 308 support
diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index 6837affc19e8..2d3f3d00e05c 100644
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -1842,3 +1842,8 @@ int ipl_report_free(struct ipl_report *report)
 }
 
 #endif
+
+bool ipl_get_secureboot(void)
+{
+	return !!ipl_secure_flag;
+}
diff --git a/arch/s390/kernel/setup.c b/arch/s390/kernel/setup.c
index 9cbf490fd162..0510ecdfc3f6 100644
--- a/arch/s390/kernel/setup.c
+++ b/arch/s390/kernel/setup.c
@@ -49,6 +49,7 @@
 #include <linux/memory.h>
 #include <linux/compat.h>
 #include <linux/start_kernel.h>
+#include <linux/security.h>
 
 #include <asm/boot_data.h>
 #include <asm/ipl.h>
@@ -1096,6 +1097,9 @@ void __init setup_arch(char **cmdline_p)
 
 	log_component_list();
 
+	if (ipl_get_secureboot())
+		security_lock_kernel_down("Secure IPL mode", LOCKDOWN_INTEGRITY_MAX);
+
 	/* Have one command line that is parsed and saved in /proc/cmdline */
 	/* boot_command_line has been already set up in early.c */
 	*cmdline_p = boot_command_line;
-- 
2.24.1