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authorIngo Molnar <mingo@kernel.org>2015-02-19 12:06:04 +0100
committerIngo Molnar <mingo@kernel.org>2015-02-19 12:31:34 +0100
commita267b0a349bb021c010e36a2a13e1e16657b1b0f (patch)
tree4438a10ecc864f15ce6f37c1764fffa995a9a175
parentee408b4207c8281a91f039e89d06de264d319466 (diff)
parent4e7c22d447bb6d7e37bfe39ff658486ae78e8d77 (diff)
Merge branch 'tip-x86-kaslr' of git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp into x86/urgent
Pull ASLR and kASLR fixes from Borislav Petkov: - Add a global flag announcing KASLR state so that relevant code can do informed decisions based on its setting. (Jiri Kosina) - Fix a stack randomization entropy decrease bug. (Hector Marco-Gisbert) Signed-off-by: Ingo Molnar <mingo@kernel.org>
-rw-r--r--arch/x86/boot/compressed/aslr.c34
-rw-r--r--arch/x86/boot/compressed/misc.c3
-rw-r--r--arch/x86/boot/compressed/misc.h6
-rw-r--r--arch/x86/include/asm/page_types.h3
-rw-r--r--arch/x86/include/uapi/asm/bootparam.h1
-rw-r--r--arch/x86/kernel/module.c11
-rw-r--r--arch/x86/kernel/setup.c22
-rw-r--r--arch/x86/mm/mmap.c6
-rw-r--r--fs/binfmt_elf.c5
9 files changed, 69 insertions, 22 deletions
diff --git a/arch/x86/boot/compressed/aslr.c b/arch/x86/boot/compressed/aslr.c
index bb1376381985..7083c16cccba 100644
--- a/arch/x86/boot/compressed/aslr.c
+++ b/arch/x86/boot/compressed/aslr.c
@@ -14,6 +14,13 @@
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
@@ -295,7 +302,29 @@ static unsigned long find_random_addr(unsigned long minimum,
return slots_fetch_random();
}
-unsigned char *choose_kernel_location(unsigned char *input,
+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 long input_size,
unsigned char *output,
unsigned long output_size)
@@ -306,14 +335,17 @@ unsigned char *choose_kernel_location(unsigned char *input,
#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,
diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index a950864a64da..5903089c818f 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -401,7 +401,8 @@ 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(input_data, input_len, output,
+ output = choose_kernel_location(real_mode, input_data, input_len,
+ output,
output_len > run_size ? output_len
: run_size);
diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h
index 24e3e569a13c..6d6730743024 100644
--- a/arch/x86/boot/compressed/misc.h
+++ b/arch/x86/boot/compressed/misc.h
@@ -56,7 +56,8 @@ int cmdline_find_option_bool(const char *option);
#if CONFIG_RANDOMIZE_BASE
/* aslr.c */
-unsigned char *choose_kernel_location(unsigned char *input,
+unsigned char *choose_kernel_location(struct boot_params *params,
+ unsigned char *input,
unsigned long input_size,
unsigned char *output,
unsigned long output_size);
@@ -64,7 +65,8 @@ unsigned char *choose_kernel_location(unsigned char *input,
bool has_cpuflag(int flag);
#else
static inline
-unsigned char *choose_kernel_location(unsigned char *input,
+unsigned char *choose_kernel_location(struct boot_params *params,
+ unsigned char *input,
unsigned long input_size,
unsigned char *output,
unsigned long output_size)
diff --git a/arch/x86/include/asm/page_types.h b/arch/x86/include/asm/page_types.h
index f97fbe3abb67..3d43ce36eaba 100644
--- a/arch/x86/include/asm/page_types.h
+++ b/arch/x86/include/asm/page_types.h
@@ -3,6 +3,7 @@
#include <linux/const.h>
#include <linux/types.h>
+#include <asm/bootparam.h>
/* PAGE_SHIFT determines the page size */
#define PAGE_SHIFT 12
@@ -51,6 +52,8 @@ 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;
diff --git a/arch/x86/include/uapi/asm/bootparam.h b/arch/x86/include/uapi/asm/bootparam.h
index 225b0988043a..44e6dd7e36a2 100644
--- a/arch/x86/include/uapi/asm/bootparam.h
+++ b/arch/x86/include/uapi/asm/bootparam.h
@@ -7,6 +7,7 @@
#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
diff --git a/arch/x86/kernel/module.c b/arch/x86/kernel/module.c
index e69f9882bf95..c3c59a3a14ad 100644
--- a/arch/x86/kernel/module.c
+++ b/arch/x86/kernel/module.c
@@ -32,6 +32,7 @@
#include <asm/page.h>
#include <asm/pgtable.h>
+#include <asm/page_types.h>
#if 0
#define DEBUGP(fmt, ...) \
@@ -46,21 +47,13 @@ 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 (randomize_modules) {
+ if (kaslr_enabled) {
mutex_lock(&module_kaslr_mutex);
/*
* Calculate the module_load_offset the first time this
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index c4648adadd7d..0d8071d7addb 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -121,6 +121,8 @@
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
@@ -424,6 +426,11 @@ 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;
@@ -449,6 +456,9 @@ 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;
}
@@ -831,10 +841,14 @@ static void __init trim_low_memory_range(void)
static int
dump_kernel_offset(struct notifier_block *self, unsigned long v, void *p)
{
- 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);
+ 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");
return 0;
}
diff --git a/arch/x86/mm/mmap.c b/arch/x86/mm/mmap.c
index 919b91205cd4..df4552bd239e 100644
--- a/arch/x86/mm/mmap.c
+++ b/arch/x86/mm/mmap.c
@@ -35,12 +35,12 @@ struct va_alignment __read_mostly va_align = {
.flags = -1,
};
-static unsigned int stack_maxrandom_size(void)
+static unsigned long stack_maxrandom_size(void)
{
- unsigned int max = 0;
+ unsigned long max = 0;
if ((current->flags & PF_RANDOMIZE) &&
!(current->personality & ADDR_NO_RANDOMIZE)) {
- max = ((-1U) & STACK_RND_MASK) << PAGE_SHIFT;
+ max = ((-1UL) & STACK_RND_MASK) << PAGE_SHIFT;
}
return max;
diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 02b16910f4c9..995986b8e36b 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -645,11 +645,12 @@ out:
static unsigned long randomize_stack_top(unsigned long stack_top)
{
- unsigned int random_variable = 0;
+ unsigned long random_variable = 0;
if ((current->flags & PF_RANDOMIZE) &&
!(current->personality & ADDR_NO_RANDOMIZE)) {
- random_variable = get_random_int() & STACK_RND_MASK;
+ random_variable = (unsigned long) get_random_int();
+ random_variable &= STACK_RND_MASK;
random_variable <<= PAGE_SHIFT;
}
#ifdef CONFIG_STACK_GROWSUP