From c4f39a6c74389fcc93ac39056ef342f32ab57a23 Mon Sep 17 00:00:00 2001
From: Domenico Andreoli <domenico.andreoli@linux.com>
Date: Thu, 7 May 2020 09:19:53 +0200
Subject: [PATCH] PM: hibernate: Split off snapshot dev option
Git-commit: c4f39a6c74389fcc93ac39056ef342f32ab57a23
Patch-mainline: v5.8-rc1
References: jsc#SLE-13338

Make it possible to reduce the attack surface in case the snapshot
device is not to be used from userspace.

Signed-off-by: Domenico Andreoli <domenico.andreoli@linux.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Coly Li <colyli@suse.de>

---
 kernel/power/Kconfig  |   12 ++++++++++++
 kernel/power/Makefile |    3 ++-
 2 files changed, 14 insertions(+), 1 deletion(-)

--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -80,6 +80,18 @@ config HIBERNATION
 config ARCH_SAVE_PAGE_KEYS
 	bool
 
+config HIBERNATION_SNAPSHOT_DEV
+	bool "Userspace snapshot device"
+	depends on HIBERNATION
+	default y
+	---help---
+	  Device used by the uswsusp tools.
+
+	  Say N if no snapshotting from userspace is needed, this also
+	  reduces the attack surface of the kernel.
+
+	  If in doubt, say Y.
+
 config PM_STD_PARTITION
 	string "Default resume partition"
 	depends on HIBERNATION
--- a/kernel/power/Makefile
+++ b/kernel/power/Makefile
@@ -10,7 +10,8 @@ obj-$(CONFIG_VT_CONSOLE_SLEEP)	+= consol
 obj-$(CONFIG_FREEZER)		+= process.o
 obj-$(CONFIG_SUSPEND)		+= suspend.o
 obj-$(CONFIG_PM_TEST_SUSPEND)	+= suspend_test.o
-obj-$(CONFIG_HIBERNATION)	+= hibernate.o snapshot.o swap.o user.o
+obj-$(CONFIG_HIBERNATION)	+= hibernate.o snapshot.o swap.o
+obj-$(CONFIG_HIBERNATION_SNAPSHOT_DEV) += user.o
 obj-$(CONFIG_PM_AUTOSLEEP)	+= autosleep.o
 obj-$(CONFIG_PM_WAKELOCKS)	+= wakelock.o