x86, kaslr: boot-time selectable with hibernation

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>
Acked-by: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Kees Cook 2014-06-13 13:30:36 -07:00 committed by Rafael J. Wysocki
parent a6e15a3904
commit 24f2e0273f
4 changed files with 22 additions and 7 deletions

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@ -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

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@ -1672,7 +1672,6 @@ 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

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@ -289,10 +289,17 @@ unsigned char *choose_kernel_location(unsigned char *input,
unsigned long choice = (unsigned long)output;
unsigned long random;
if (cmdline_find_option_bool("nokaslr")) {
debug_putstr("KASLR disabled...\n");
#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 by cmdline...\n");
goto out;
}
#endif
/* Record the various known unsafe memory ranges. */
mem_avoid_init((unsigned long)input, input_size,

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@ -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);