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Revert "x86/mm/ASLR: Propagate base load address calculation" 

This reverts commit:

  f47233c2d3 ("x86/mm/ASLR: Propagate base load address calculation")

The main reason for the revert is that the new boot flag does not work
at all currently, and in order to make this work, we need non-trivial
changes to the x86 boot code which we didn't manage to get done in
time for merging.

And even if we did, they would've been too risky so instead of
rushing things and break booting 4.1 on boxes left and right, we
will be very strict and conservative and will take our time with
this to fix and test it properly.

Reported-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: H. Peter Anvin <hpa@linux.intel.com
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Junjie Mao <eternal.n08@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Link: http://lkml.kernel.org/r/20150316100628.GD22995@pd.tnic
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Borislav Petkov 2015-03-16 11:06:28 +01:00 committed by Ingo Molnar
parent f4c3686386
commit 69797dafe3
7 changed files with 17 additions and 61 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

34
arch/x86/boot/compressed/aslr.c
View File

@ -14,13 +14,6 @@
static const char build_str[] = UTS_RELEASE " (" LINUX_COMPILE_BY "@"
LINUX_COMPILE_HOST ") (" LINUX_COMPILER ") " UTS_VERSION;
struct kaslr_setup_data {
__u64 next;
__u32 type;
__u32 len;
__u8 data[1];
} kaslr_setup_data;
#define I8254_PORT_CONTROL 0x43
#define I8254_PORT_COUNTER0 0x40
#define I8254_CMD_READBACK 0xC0
@ -302,29 +295,7 @@ static unsigned long find_random_addr(unsigned long minimum,
return slots_fetch_random();
}
static void add_kaslr_setup_data(struct boot_params *params, __u8 enabled)
{
struct setup_data *data;
kaslr_setup_data.type = SETUP_KASLR;
kaslr_setup_data.len = 1;
kaslr_setup_data.next = 0;
kaslr_setup_data.data[0] = enabled;
data = (struct setup_data *)(unsigned long)params->hdr.setup_data;
while (data && data->next)
data = (struct setup_data *)(unsigned long)data->next;
if (data)
data->next = (unsigned long)&kaslr_setup_data;
else
params->hdr.setup_data = (unsigned long)&kaslr_setup_data;
}
unsigned char *choose_kernel_location(struct boot_params *params,
unsigned char *input,
unsigned char *choose_kernel_location(unsigned char *input,
unsigned long input_size,
unsigned char *output,
unsigned long output_size)
@ -335,17 +306,14 @@ unsigned char *choose_kernel_location(struct boot_params *params,
#ifdef CONFIG_HIBERNATION
if (!cmdline_find_option_bool("kaslr")) {
debug_putstr("KASLR disabled by default...\n");
add_kaslr_setup_data(params, 0);
goto out;
}
#else
if (cmdline_find_option_bool("nokaslr")) {
debug_putstr("KASLR disabled by cmdline...\n");
add_kaslr_setup_data(params, 0);
goto out;
}
#endif
add_kaslr_setup_data(params, 1);
/* Record the various known unsafe memory ranges. */
mem_avoid_init((unsigned long)input, input_size,

3
arch/x86/boot/compressed/misc.c
View File

@ -401,8 +401,7 @@ asmlinkage __visible void *decompress_kernel(void *rmode, memptr heap,
* the entire decompressed kernel plus relocation table, or the
* entire decompressed kernel plus .bss and .brk sections.
*/
output = choose_kernel_location(real_mode, input_data, input_len,
output,
output = choose_kernel_location(input_data, input_len, output,
output_len > run_size ? output_len
: run_size);

6
arch/x86/boot/compressed/misc.h
View File

@ -57,8 +57,7 @@ int cmdline_find_option_bool(const char *option);
#if CONFIG_RANDOMIZE_BASE
/* aslr.c */
unsigned char *choose_kernel_location(struct boot_params *params,
unsigned char *input,
unsigned char *choose_kernel_location(unsigned char *input,
unsigned long input_size,
unsigned char *output,
unsigned long output_size);
@ -66,8 +65,7 @@ unsigned char *choose_kernel_location(struct boot_params *params,
bool has_cpuflag(int flag);
#else
static inline
unsigned char *choose_kernel_location(struct boot_params *params,
unsigned char *input,
unsigned char *choose_kernel_location(unsigned char *input,
unsigned long input_size,
unsigned char *output,
unsigned long output_size)

2
arch/x86/include/asm/page_types.h
View File

@ -51,8 +51,6 @@ extern int devmem_is_allowed(unsigned long pagenr);
extern unsigned long max_low_pfn_mapped;
extern unsigned long max_pfn_mapped;
extern bool kaslr_enabled;
static inline phys_addr_t get_max_mapped(void)
{
return (phys_addr_t)max_pfn_mapped << PAGE_SHIFT;

1
arch/x86/include/uapi/asm/bootparam.h
View File

@ -7,7 +7,6 @@
#define SETUP_DTB 2
#define SETUP_PCI 3
#define SETUP_EFI 4
#define SETUP_KASLR 5
/* ram_size flags */
#define RAMDISK_IMAGE_START_MASK 0x07FF

10
arch/x86/kernel/module.c
View File

@ -47,13 +47,21 @@ do { \
#ifdef CONFIG_RANDOMIZE_BASE
static unsigned long module_load_offset;
static int randomize_modules = 1;
/* Mutex protects the module_load_offset. */
static DEFINE_MUTEX(module_kaslr_mutex);
static int __init parse_nokaslr(char *p)
{
randomize_modules = 0;
return 0;
}
early_param("nokaslr", parse_nokaslr);
static unsigned long int get_module_load_offset(void)
{
if (kaslr_enabled) {
if (randomize_modules) {
mutex_lock(&module_kaslr_mutex);
/*
* Calculate the module_load_offset the first time this

22
arch/x86/kernel/setup.c
View File

@ -122,8 +122,6 @@
unsigned long max_low_pfn_mapped;
unsigned long max_pfn_mapped;
bool __read_mostly kaslr_enabled = false;
#ifdef CONFIG_DMI
RESERVE_BRK(dmi_alloc, 65536);
#endif
@ -427,11 +425,6 @@ static void __init reserve_initrd(void)
}
#endif /* CONFIG_BLK_DEV_INITRD */
static void __init parse_kaslr_setup(u64 pa_data, u32 data_len)
{
kaslr_enabled = (bool)(pa_data + sizeof(struct setup_data));
}
static void __init parse_setup_data(void)
{
struct setup_data *data;
@ -457,9 +450,6 @@ static void __init parse_setup_data(void)
case SETUP_EFI:
parse_efi_setup(pa_data, data_len);
break;
case SETUP_KASLR:
parse_kaslr_setup(pa_data, data_len);
break;
default:
break;
}
@ -842,14 +832,10 @@ static void __init trim_low_memory_range(void)
static int
dump_kernel_offset(struct notifier_block *self, unsigned long v, void *p)
{
if (kaslr_enabled)
pr_emerg("Kernel Offset: 0x%lx from 0x%lx (relocation range: 0x%lx-0x%lx)\n",
(unsigned long)&_text - __START_KERNEL,
__START_KERNEL,
__START_KERNEL_map,
MODULES_VADDR-1);
else
pr_emerg("Kernel Offset: disabled\n");
pr_emerg("Kernel Offset: 0x%lx from 0x%lx "
"(relocation range: 0x%lx-0x%lx)\n",
(unsigned long)&_text - __START_KERNEL, __START_KERNEL,
__START_KERNEL_map, MODULES_VADDR-1);
return 0;
}