* [PATCH v3 1/2] hibernate: create "nohibernate" boot parameter
2014-06-13 20:30 [PATCH v3 0/2] make kASLR vs hibernation boot-time selectable Kees Cook
@ 2014-06-13 20:30 ` Kees Cook
2014-06-13 20:30 ` [PATCH v3 2/2] x86, kaslr: boot-time selectable with hibernation Kees Cook
2014-06-13 23:25 ` [PATCH v3 0/2] make kASLR vs hibernation boot-time selectable Rafael J. Wysocki
2 siblings, 0 replies; 7+ messages in thread
From: Kees Cook @ 2014-06-13 20:30 UTC (permalink / raw)
To: linux-kernel
Cc: Kees Cook, Pavel Machek, Josh Boyer, H. Peter Anvin,
Randy Dunlap, Thomas Gleixner, Ingo Molnar, x86,
Rafael J. Wysocki, Len Brown, Wei Yongjun, linux-doc, linux-pm
To support using kernel features that are not compatible with hibernation,
this creates the "nohibernate" kernel boot parameter to disable both
hibernation and resume. This allows hibernation support to be a boot-time
choice instead of only a compile-time choice.
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
---
Documentation/kernel-parameters.txt | 3 +++
include/linux/suspend.h | 2 ++
kernel/power/hibernate.c | 31 ++++++++++++++++++++++++++++++-
kernel/power/main.c | 6 ++----
kernel/power/user.c | 3 +++
5 files changed, 40 insertions(+), 5 deletions(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 6eaa9cdb7094..f8f0466b8b1d 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2184,6 +2184,8 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
in certain environments such as networked servers or
real-time systems.
+ nohibernate [HIBERNATION] Disable hibernation and resume.
+
nohz= [KNL] Boottime enable/disable dynamic ticks
Valid arguments: on, off
Default: on
@@ -2980,6 +2982,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
noresume Don't check if there's a hibernation image
present during boot.
nocompress Don't compress/decompress hibernation images.
+ no Disable hibernation and resume.
retain_initrd [RAM] Keep initrd memory after extraction
diff --git a/include/linux/suspend.h b/include/linux/suspend.h
index f76994b9396c..519064e0c943 100644
--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h
@@ -327,6 +327,7 @@ extern unsigned long get_safe_page(gfp_t gfp_mask);
extern void hibernation_set_ops(const struct platform_hibernation_ops *ops);
extern int hibernate(void);
extern bool system_entering_hibernation(void);
+extern bool hibernation_available(void);
asmlinkage int swsusp_save(void);
extern struct pbe *restore_pblist;
#else /* CONFIG_HIBERNATION */
@@ -339,6 +340,7 @@ static inline void swsusp_unset_page_free(struct page *p) {}
static inline void hibernation_set_ops(const struct platform_hibernation_ops *ops) {}
static inline int hibernate(void) { return -ENOSYS; }
static inline bool system_entering_hibernation(void) { return false; }
+static inline bool hibernation_available(void) { return false; }
#endif /* CONFIG_HIBERNATION */
/* Hibernation and suspend events */
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 49e0a20fd010..258f492f0347 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -35,6 +35,7 @@
static int nocompress;
static int noresume;
+static int nohibernate;
static int resume_wait;
static unsigned int resume_delay;
static char resume_file[256] = CONFIG_PM_STD_PARTITION;
@@ -62,6 +63,11 @@ bool freezer_test_done;
static const struct platform_hibernation_ops *hibernation_ops;
+bool hibernation_available(void)
+{
+ return (nohibernate == 0);
+}
+
/**
* hibernation_set_ops - Set the global hibernate operations.
* @ops: Hibernation operations to use in subsequent hibernation transitions.
@@ -642,6 +648,11 @@ int hibernate(void)
{
int error;
+ if (!hibernation_available()) {
+ pr_debug("PM: Hibernation not available.\n");
+ return -EPERM;
+ }
+
lock_system_sleep();
/* The snapshot device should not be opened while we're running */
if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
@@ -734,7 +745,7 @@ static int software_resume(void)
/*
* If the user said "noresume".. bail out early.
*/
- if (noresume)
+ if (noresume || !hibernation_available())
return 0;
/*
@@ -900,6 +911,9 @@ static ssize_t disk_show(struct kobject *kobj, struct kobj_attribute *attr,
int i;
char *start = buf;
+ if (!hibernation_available())
+ return sprintf(buf, "[disabled]\n");
+
for (i = HIBERNATION_FIRST; i <= HIBERNATION_MAX; i++) {
if (!hibernation_modes[i])
continue;
@@ -934,6 +948,9 @@ static ssize_t disk_store(struct kobject *kobj, struct kobj_attribute *attr,
char *p;
int mode = HIBERNATION_INVALID;
+ if (!hibernation_available())
+ return -EPERM;
+
p = memchr(buf, '\n', n);
len = p ? p - buf : n;
@@ -1101,6 +1118,10 @@ static int __init hibernate_setup(char *str)
noresume = 1;
else if (!strncmp(str, "nocompress", 10))
nocompress = 1;
+ else if (!strncmp(str, "no", 2)) {
+ noresume = 1;
+ nohibernate = 1;
+ }
return 1;
}
@@ -1125,9 +1146,17 @@ static int __init resumedelay_setup(char *str)
return 1;
}
+static int __init nohibernate_setup(char *str)
+{
+ noresume = 1;
+ nohibernate = 1;
+ return 1;
+}
+
__setup("noresume", noresume_setup);
__setup("resume_offset=", resume_offset_setup);
__setup("resume=", resume_setup);
__setup("hibernate=", hibernate_setup);
__setup("resumewait", resumewait_setup);
__setup("resumedelay=", resumedelay_setup);
+__setup("nohibernate", nohibernate_setup);
diff --git a/kernel/power/main.c b/kernel/power/main.c
index 573410d6647e..8e90f330f139 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -300,13 +300,11 @@ static ssize_t state_show(struct kobject *kobj, struct kobj_attribute *attr,
s += sprintf(s,"%s ", pm_states[i].label);
#endif
-#ifdef CONFIG_HIBERNATION
- s += sprintf(s, "%s\n", "disk");
-#else
+ if (hibernation_available())
+ s += sprintf(s, "disk ");
if (s != buf)
/* convert the last space to a newline */
*(s-1) = '\n';
-#endif
return (s - buf);
}
diff --git a/kernel/power/user.c b/kernel/power/user.c
index 98d357584cd6..526e8911460a 100644
--- a/kernel/power/user.c
+++ b/kernel/power/user.c
@@ -49,6 +49,9 @@ static int snapshot_open(struct inode *inode, struct file *filp)
struct snapshot_data *data;
int error;
+ if (!hibernation_available())
+ return -EPERM;
+
lock_system_sleep();
if (!atomic_add_unless(&snapshot_device_available, -1, 0)) {
--
1.7.9.5
^ permalink raw reply [flat|nested] 7+ messages in thread* [PATCH v3 2/2] x86, kaslr: boot-time selectable with hibernation
2014-06-13 20:30 [PATCH v3 0/2] make kASLR vs hibernation boot-time selectable Kees Cook
2014-06-13 20:30 ` [PATCH v3 1/2] hibernate: create "nohibernate" boot parameter Kees Cook
@ 2014-06-13 20:30 ` Kees Cook
2014-06-13 20:39 ` Pavel Machek
2014-06-13 23:25 ` [PATCH v3 0/2] make kASLR vs hibernation boot-time selectable Rafael J. Wysocki
2 siblings, 1 reply; 7+ messages in thread
From: Kees Cook @ 2014-06-13 20:30 UTC (permalink / raw)
To: linux-kernel
Cc: Kees Cook, Pavel Machek, Josh Boyer, H. Peter Anvin,
Randy Dunlap, Thomas Gleixner, Ingo Molnar, x86,
Rafael J. Wysocki, Len Brown, Wei Yongjun, linux-doc, linux-pm
Changes kASLR from being compile-time selectable (blocked by
CONFIG_HIBERNATION), to being boot-time selectable (with hibernation
available by default) via the "kaslr" kernel command line.
Signed-off-by: Kees Cook <keescook@chromium.org>
---
Documentation/kernel-parameters.txt | 11 +++++++----
arch/x86/Kconfig | 1 -
arch/x86/boot/compressed/aslr.c | 9 ++++++++-
kernel/power/hibernate.c | 6 ++++++
4 files changed, 21 insertions(+), 6 deletions(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index f8f0466b8b1d..884904975d0b 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1474,6 +1474,13 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
js= [HW,JOY] Analog joystick
See Documentation/input/joystick.txt.
+ kaslr/nokaslr [X86]
+ Enable/disable kernel and module base offset ASLR
+ (Address Space Layout Randomization) if built into
+ the kernel. When CONFIG_HIBERNATION is selected,
+ kASLR is disabled by default. When kASLR is enabled,
+ hibernation will be disabled.
+
keepinitrd [HW,ARM]
kernelcore=nn[KMG] [KNL,X86,IA-64,PPC] This parameter
@@ -2110,10 +2117,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
noapic [SMP,APIC] Tells the kernel to not make use of any
IOAPICs that may be present in the system.
- nokaslr [X86]
- Disable kernel and module base offset ASLR (Address
- Space Layout Randomization) if built into the kernel.
-
noautogroup Disable scheduler automatic task group creation.
nobats [PPC] Do not use BATs for mapping kernel lowmem
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index b660088c220d..7fdb639f1b63 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1671,7 +1671,6 @@ config RELOCATABLE
config RANDOMIZE_BASE
bool "Randomize the address of the kernel image"
depends on RELOCATABLE
- depends on !HIBERNATION
default n
---help---
Randomizes the physical and virtual address at which the
diff --git a/arch/x86/boot/compressed/aslr.c b/arch/x86/boot/compressed/aslr.c
index 4dbf967da50d..fc6091abedb7 100644
--- a/arch/x86/boot/compressed/aslr.c
+++ b/arch/x86/boot/compressed/aslr.c
@@ -289,10 +289,17 @@ unsigned char *choose_kernel_location(unsigned char *input,
unsigned long choice = (unsigned long)output;
unsigned long random;
+#ifdef CONFIG_HIBERNATION
+ if (!cmdline_find_option_bool("kaslr")) {
+ debug_putstr("KASLR disabled by default...\n");
+ goto out;
+ }
+#else
if (cmdline_find_option_bool("nokaslr")) {
- debug_putstr("KASLR disabled...\n");
+ debug_putstr("KASLR disabled by cmdline...\n");
goto out;
}
+#endif
/* Record the various known unsafe memory ranges. */
mem_avoid_init((unsigned long)input, input_size,
diff --git a/kernel/power/hibernate.c b/kernel/power/hibernate.c
index 258f492f0347..fcc2611d3f14 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -1153,6 +1153,11 @@ static int __init nohibernate_setup(char *str)
return 1;
}
+static int __init kaslr_nohibernate_setup(char *str)
+{
+ return nohibernate_setup(str);
+}
+
__setup("noresume", noresume_setup);
__setup("resume_offset=", resume_offset_setup);
__setup("resume=", resume_setup);
@@ -1160,3 +1165,4 @@ __setup("hibernate=", hibernate_setup);
__setup("resumewait", resumewait_setup);
__setup("resumedelay=", resumedelay_setup);
__setup("nohibernate", nohibernate_setup);
+__setup("kaslr", kaslr_nohibernate_setup);
--
1.7.9.5
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [PATCH v3 0/2] make kASLR vs hibernation boot-time selectable
2014-06-13 20:30 [PATCH v3 0/2] make kASLR vs hibernation boot-time selectable Kees Cook
2014-06-13 20:30 ` [PATCH v3 1/2] hibernate: create "nohibernate" boot parameter Kees Cook
2014-06-13 20:30 ` [PATCH v3 2/2] x86, kaslr: boot-time selectable with hibernation Kees Cook
@ 2014-06-13 23:25 ` Rafael J. Wysocki
2014-06-14 6:09 ` Kees Cook
2 siblings, 1 reply; 7+ messages in thread
From: Rafael J. Wysocki @ 2014-06-13 23:25 UTC (permalink / raw)
To: Kees Cook
Cc: linux-kernel, Pavel Machek, Josh Boyer, H. Peter Anvin,
Randy Dunlap, Thomas Gleixner, Ingo Molnar, x86, Len Brown,
Wei Yongjun, linux-doc, linux-pm
On Friday, June 13, 2014 01:30:34 PM Kees Cook wrote:
> Distros want to be able to offer CONFIG_RANDOMIZE_BASE as well as
> CONFIG_HIBERNATION in a single kernel. Instead of making kASLR depend on
> !HIBERNATION at compile time, allow kaslr to be selectable at boot time
> (via "kaslr" kernel command line), which will disable hibernation in the
> kernel. In this way the end user can choose which feature they want more
> with hibernation continuing to stay enabled by default (no surprises).
>
> This also has the benefit of being able to entirely disable hibernation
> from the kernel command line, regardless of kASLR, which is a separately
> desired feature as well.
>
> v3:
> - switch from EINVAL to EPERM (pavel, jwboyer)
> v2:
> - rework using kernel command line instead of hibernation_mode (rjw)
That looks kind of OK.
Do you want me to push this through my tree?
Rafael
^ permalink raw reply [flat|nested] 7+ messages in thread