From: Kees Cook <keesc...@chromium.org>
commit 24f2e0273f80ec262a772059e140a0adef35296d upstream
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 <keesc...@chromium.org>
Acked-by: Pavel Machek <pa...@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wyso...@intel.com>
Signed-off-by: Yang Shi <yang....@windriver.com>
---
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 580a60c..49e0ac1 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1416,6 +1416,13 @@ 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
@@ -2052,10 +2059,6 @@ 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 0af5250..402ae4b 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -1701,7 +1701,6 @@ 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 4dbf967..fc6091a 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 37170d4..b713f39 100644
--- a/kernel/power/hibernate.c
+++ b/kernel/power/hibernate.c
@@ -1111,9 +1111,15 @@ static int __init resumedelay_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);
__setup("hibernate=", hibernate_setup);
__setup("resumewait", resumewait_setup);
__setup("resumedelay=", resumedelay_setup);
+__setup("kaslr", kaslr_nohibernate_setup);
--
2.0.2
--
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