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Commit 69797daf authored by Borislav Petkov's avatar Borislav Petkov Committed by Ingo Molnar
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Revert "x86/mm/ASLR: Propagate base load address calculation" 



This reverts commit:

  f47233c2 ("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: default avatarYinghai Lu <yinghai@kernel.org>
Signed-off-by: default avatarBorislav 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: default avatarIngo Molnar <mingo@kernel.org>
parent f4c36863

arch/x86/boot/compressed/aslr.c

+1 −33
Original line number Diff line number Diff line
@@ -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,

arch/x86/boot/compressed/misc.c

+1 −2
Original line number Diff line number Diff line
@@ -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);

arch/x86/boot/compressed/misc.h

+2 −4
Original line number Diff line number Diff line
@@ -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)

arch/x86/include/asm/page_types.h

+0 −2
Original line number Diff line number Diff line
@@ -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;

arch/x86/include/uapi/asm/bootparam.h

+0 −1
Original line number Diff line number Diff line
@@ -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