* [kernel-hardening] [PATCH] x86/mm: Enable KASLR for vmemmap memory region (x86_64)
@ 2016-07-27 15:59 ` Thomas Garnier
0 siblings, 0 replies; 9+ messages in thread
From: Thomas Garnier @ 2016-07-27 15:59 UTC (permalink / raw)
To: Thomas Gleixner, Ingo Molnar, H . Peter Anvin, Thomas Garnier, Kees Cook
Cc: x86, linux-kernel, kernel-hardening
Add vmemmap in the list of randomized memory regions.
The vmemmap region holds a representation of the physical memory (through
a struct page array). An attacker could use this region to disclose the
kernel memory layout (walking the page linked list).
Signed-off-by: Thomas Garnier <thgarnie@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
Missing patch didn't pick-up by the tip bot on KASLR memory randomization.
Resending after rebase on tip and tests as discussed with Ingo.
Based on tip 4bcc8cf6ab5932cbb2511c8e18065e61b069f21c
---
arch/x86/include/asm/kaslr.h | 1 +
arch/x86/include/asm/pgtable_64_types.h | 4 +++-
arch/x86/mm/kaslr.c | 24 +++++++++++++++++++++++-
3 files changed, 27 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/kaslr.h b/arch/x86/include/asm/kaslr.h
index 2674ee3..1052a79 100644
--- a/arch/x86/include/asm/kaslr.h
+++ b/arch/x86/include/asm/kaslr.h
@@ -6,6 +6,7 @@ unsigned long kaslr_get_random_long(const char *purpose);
#ifdef CONFIG_RANDOMIZE_MEMORY
extern unsigned long page_offset_base;
extern unsigned long vmalloc_base;
+extern unsigned long vmemmap_base;
void kernel_randomize_memory(void);
#else
diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
index 6fdef9e..3a26420 100644
--- a/arch/x86/include/asm/pgtable_64_types.h
+++ b/arch/x86/include/asm/pgtable_64_types.h
@@ -57,11 +57,13 @@ typedef struct { pteval_t pte; } pte_t;
#define MAXMEM _AC(__AC(1, UL) << MAX_PHYSMEM_BITS, UL)
#define VMALLOC_SIZE_TB _AC(32, UL)
#define __VMALLOC_BASE _AC(0xffffc90000000000, UL)
-#define VMEMMAP_START _AC(0xffffea0000000000, UL)
+#define __VMEMMAP_BASE _AC(0xffffea0000000000, UL)
#ifdef CONFIG_RANDOMIZE_MEMORY
#define VMALLOC_START vmalloc_base
+#define VMEMMAP_START vmemmap_base
#else
#define VMALLOC_START __VMALLOC_BASE
+#define VMEMMAP_START __VMEMMAP_BASE
#endif /* CONFIG_RANDOMIZE_MEMORY */
#define VMALLOC_END (VMALLOC_START + _AC((VMALLOC_SIZE_TB << 40) - 1, UL))
#define MODULES_VADDR (__START_KERNEL_map + KERNEL_IMAGE_SIZE)
diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c
index 26dccd6..3e9875f 100644
--- a/arch/x86/mm/kaslr.c
+++ b/arch/x86/mm/kaslr.c
@@ -44,13 +44,22 @@
* ensure that this order is correct and won't be changed.
*/
static const unsigned long vaddr_start = __PAGE_OFFSET_BASE;
-static const unsigned long vaddr_end = VMEMMAP_START;
+
+#if defined(CONFIG_X86_ESPFIX64)
+static const unsigned long vaddr_end = ESPFIX_BASE_ADDR;
+#elif defined(CONFIG_EFI)
+static const unsigned long vaddr_end = EFI_VA_START;
+#else
+static const unsigned long vaddr_end = __START_KERNEL_map;
+#endif
/* Default values */
unsigned long page_offset_base = __PAGE_OFFSET_BASE;
EXPORT_SYMBOL(page_offset_base);
unsigned long vmalloc_base = __VMALLOC_BASE;
EXPORT_SYMBOL(vmalloc_base);
+unsigned long vmemmap_base = __VMEMMAP_BASE;
+EXPORT_SYMBOL(vmemmap_base);
/*
* Memory regions randomized by KASLR (except modules that use a separate logic
@@ -63,6 +72,7 @@ static __initdata struct kaslr_memory_region {
} kaslr_regions[] = {
{ &page_offset_base, 64/* Maximum */ },
{ &vmalloc_base, VMALLOC_SIZE_TB },
+ { &vmemmap_base, 1 },
};
/* Get size in bytes used by the memory region */
@@ -89,6 +99,18 @@ void __init kernel_randomize_memory(void)
struct rnd_state rand_state;
unsigned long remain_entropy;
+ /*
+ * All these BUILD_BUG_ON checks ensures the memory layout is
+ * consistent with the vaddr_start/vaddr_end variables.
+ */
+ BUILD_BUG_ON(vaddr_start >= vaddr_end);
+ BUILD_BUG_ON(config_enabled(CONFIG_X86_ESPFIX64) &&
+ vaddr_end >= EFI_VA_START);
+ BUILD_BUG_ON((config_enabled(CONFIG_X86_ESPFIX64) ||
+ config_enabled(CONFIG_EFI)) &&
+ vaddr_end >= __START_KERNEL_map);
+ BUILD_BUG_ON(vaddr_end > __START_KERNEL_map);
+
if (!kaslr_memory_enabled())
return;
--
2.8.0.rc3.226.g39d4020
^ permalink raw reply related [flat|nested] 9+ messages in thread* Re: [PATCH] x86/mm: Enable KASLR for vmemmap memory region (x86_64)
2016-07-27 15:59 ` [kernel-hardening] " Thomas Garnier
@ 2016-08-01 17:09 ` Thomas Garnier
-1 siblings, 0 replies; 9+ messages in thread
From: Thomas Garnier @ 2016-08-01 17:09 UTC (permalink / raw)
To: Thomas Gleixner, Ingo Molnar, H . Peter Anvin, Thomas Garnier, Kees Cook
Cc: x86, LKML, kernel-hardening
On Wed, Jul 27, 2016 at 8:59 AM, Thomas Garnier <thgarnie@google.com> wrote:
> Add vmemmap in the list of randomized memory regions.
>
> The vmemmap region holds a representation of the physical memory (through
> a struct page array). An attacker could use this region to disclose the
> kernel memory layout (walking the page linked list).
>
> Signed-off-by: Thomas Garnier <thgarnie@google.com>
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
> Missing patch didn't pick-up by the tip bot on KASLR memory randomization.
> Resending after rebase on tip and tests as discussed with Ingo.
> Based on tip 4bcc8cf6ab5932cbb2511c8e18065e61b069f21c
Ingo: Any comment? Can you integrate it on tip?
> ---
> arch/x86/include/asm/kaslr.h | 1 +
> arch/x86/include/asm/pgtable_64_types.h | 4 +++-
> arch/x86/mm/kaslr.c | 24 +++++++++++++++++++++++-
> 3 files changed, 27 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/include/asm/kaslr.h b/arch/x86/include/asm/kaslr.h
> index 2674ee3..1052a79 100644
> --- a/arch/x86/include/asm/kaslr.h
> +++ b/arch/x86/include/asm/kaslr.h
> @@ -6,6 +6,7 @@ unsigned long kaslr_get_random_long(const char *purpose);
> #ifdef CONFIG_RANDOMIZE_MEMORY
> extern unsigned long page_offset_base;
> extern unsigned long vmalloc_base;
> +extern unsigned long vmemmap_base;
>
> void kernel_randomize_memory(void);
> #else
> diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
> index 6fdef9e..3a26420 100644
> --- a/arch/x86/include/asm/pgtable_64_types.h
> +++ b/arch/x86/include/asm/pgtable_64_types.h
> @@ -57,11 +57,13 @@ typedef struct { pteval_t pte; } pte_t;
> #define MAXMEM _AC(__AC(1, UL) << MAX_PHYSMEM_BITS, UL)
> #define VMALLOC_SIZE_TB _AC(32, UL)
> #define __VMALLOC_BASE _AC(0xffffc90000000000, UL)
> -#define VMEMMAP_START _AC(0xffffea0000000000, UL)
> +#define __VMEMMAP_BASE _AC(0xffffea0000000000, UL)
> #ifdef CONFIG_RANDOMIZE_MEMORY
> #define VMALLOC_START vmalloc_base
> +#define VMEMMAP_START vmemmap_base
> #else
> #define VMALLOC_START __VMALLOC_BASE
> +#define VMEMMAP_START __VMEMMAP_BASE
> #endif /* CONFIG_RANDOMIZE_MEMORY */
> #define VMALLOC_END (VMALLOC_START + _AC((VMALLOC_SIZE_TB << 40) - 1, UL))
> #define MODULES_VADDR (__START_KERNEL_map + KERNEL_IMAGE_SIZE)
> diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c
> index 26dccd6..3e9875f 100644
> --- a/arch/x86/mm/kaslr.c
> +++ b/arch/x86/mm/kaslr.c
> @@ -44,13 +44,22 @@
> * ensure that this order is correct and won't be changed.
> */
> static const unsigned long vaddr_start = __PAGE_OFFSET_BASE;
> -static const unsigned long vaddr_end = VMEMMAP_START;
> +
> +#if defined(CONFIG_X86_ESPFIX64)
> +static const unsigned long vaddr_end = ESPFIX_BASE_ADDR;
> +#elif defined(CONFIG_EFI)
> +static const unsigned long vaddr_end = EFI_VA_START;
> +#else
> +static const unsigned long vaddr_end = __START_KERNEL_map;
> +#endif
>
> /* Default values */
> unsigned long page_offset_base = __PAGE_OFFSET_BASE;
> EXPORT_SYMBOL(page_offset_base);
> unsigned long vmalloc_base = __VMALLOC_BASE;
> EXPORT_SYMBOL(vmalloc_base);
> +unsigned long vmemmap_base = __VMEMMAP_BASE;
> +EXPORT_SYMBOL(vmemmap_base);
>
> /*
> * Memory regions randomized by KASLR (except modules that use a separate logic
> @@ -63,6 +72,7 @@ static __initdata struct kaslr_memory_region {
> } kaslr_regions[] = {
> { &page_offset_base, 64/* Maximum */ },
> { &vmalloc_base, VMALLOC_SIZE_TB },
> + { &vmemmap_base, 1 },
> };
>
> /* Get size in bytes used by the memory region */
> @@ -89,6 +99,18 @@ void __init kernel_randomize_memory(void)
> struct rnd_state rand_state;
> unsigned long remain_entropy;
>
> + /*
> + * All these BUILD_BUG_ON checks ensures the memory layout is
> + * consistent with the vaddr_start/vaddr_end variables.
> + */
> + BUILD_BUG_ON(vaddr_start >= vaddr_end);
> + BUILD_BUG_ON(config_enabled(CONFIG_X86_ESPFIX64) &&
> + vaddr_end >= EFI_VA_START);
> + BUILD_BUG_ON((config_enabled(CONFIG_X86_ESPFIX64) ||
> + config_enabled(CONFIG_EFI)) &&
> + vaddr_end >= __START_KERNEL_map);
> + BUILD_BUG_ON(vaddr_end > __START_KERNEL_map);
> +
> if (!kaslr_memory_enabled())
> return;
>
> --
> 2.8.0.rc3.226.g39d4020
>
^ permalink raw reply [flat|nested] 9+ messages in thread* [kernel-hardening] Re: [PATCH] x86/mm: Enable KASLR for vmemmap memory region (x86_64)
@ 2016-08-01 17:09 ` Thomas Garnier
0 siblings, 0 replies; 9+ messages in thread
From: Thomas Garnier @ 2016-08-01 17:09 UTC (permalink / raw)
To: Thomas Gleixner, Ingo Molnar, H . Peter Anvin, Thomas Garnier, Kees Cook
Cc: x86, LKML, kernel-hardening
On Wed, Jul 27, 2016 at 8:59 AM, Thomas Garnier <thgarnie@google.com> wrote:
> Add vmemmap in the list of randomized memory regions.
>
> The vmemmap region holds a representation of the physical memory (through
> a struct page array). An attacker could use this region to disclose the
> kernel memory layout (walking the page linked list).
>
> Signed-off-by: Thomas Garnier <thgarnie@google.com>
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
> Missing patch didn't pick-up by the tip bot on KASLR memory randomization.
> Resending after rebase on tip and tests as discussed with Ingo.
> Based on tip 4bcc8cf6ab5932cbb2511c8e18065e61b069f21c
Ingo: Any comment? Can you integrate it on tip?
> ---
> arch/x86/include/asm/kaslr.h | 1 +
> arch/x86/include/asm/pgtable_64_types.h | 4 +++-
> arch/x86/mm/kaslr.c | 24 +++++++++++++++++++++++-
> 3 files changed, 27 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/include/asm/kaslr.h b/arch/x86/include/asm/kaslr.h
> index 2674ee3..1052a79 100644
> --- a/arch/x86/include/asm/kaslr.h
> +++ b/arch/x86/include/asm/kaslr.h
> @@ -6,6 +6,7 @@ unsigned long kaslr_get_random_long(const char *purpose);
> #ifdef CONFIG_RANDOMIZE_MEMORY
> extern unsigned long page_offset_base;
> extern unsigned long vmalloc_base;
> +extern unsigned long vmemmap_base;
>
> void kernel_randomize_memory(void);
> #else
> diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
> index 6fdef9e..3a26420 100644
> --- a/arch/x86/include/asm/pgtable_64_types.h
> +++ b/arch/x86/include/asm/pgtable_64_types.h
> @@ -57,11 +57,13 @@ typedef struct { pteval_t pte; } pte_t;
> #define MAXMEM _AC(__AC(1, UL) << MAX_PHYSMEM_BITS, UL)
> #define VMALLOC_SIZE_TB _AC(32, UL)
> #define __VMALLOC_BASE _AC(0xffffc90000000000, UL)
> -#define VMEMMAP_START _AC(0xffffea0000000000, UL)
> +#define __VMEMMAP_BASE _AC(0xffffea0000000000, UL)
> #ifdef CONFIG_RANDOMIZE_MEMORY
> #define VMALLOC_START vmalloc_base
> +#define VMEMMAP_START vmemmap_base
> #else
> #define VMALLOC_START __VMALLOC_BASE
> +#define VMEMMAP_START __VMEMMAP_BASE
> #endif /* CONFIG_RANDOMIZE_MEMORY */
> #define VMALLOC_END (VMALLOC_START + _AC((VMALLOC_SIZE_TB << 40) - 1, UL))
> #define MODULES_VADDR (__START_KERNEL_map + KERNEL_IMAGE_SIZE)
> diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c
> index 26dccd6..3e9875f 100644
> --- a/arch/x86/mm/kaslr.c
> +++ b/arch/x86/mm/kaslr.c
> @@ -44,13 +44,22 @@
> * ensure that this order is correct and won't be changed.
> */
> static const unsigned long vaddr_start = __PAGE_OFFSET_BASE;
> -static const unsigned long vaddr_end = VMEMMAP_START;
> +
> +#if defined(CONFIG_X86_ESPFIX64)
> +static const unsigned long vaddr_end = ESPFIX_BASE_ADDR;
> +#elif defined(CONFIG_EFI)
> +static const unsigned long vaddr_end = EFI_VA_START;
> +#else
> +static const unsigned long vaddr_end = __START_KERNEL_map;
> +#endif
>
> /* Default values */
> unsigned long page_offset_base = __PAGE_OFFSET_BASE;
> EXPORT_SYMBOL(page_offset_base);
> unsigned long vmalloc_base = __VMALLOC_BASE;
> EXPORT_SYMBOL(vmalloc_base);
> +unsigned long vmemmap_base = __VMEMMAP_BASE;
> +EXPORT_SYMBOL(vmemmap_base);
>
> /*
> * Memory regions randomized by KASLR (except modules that use a separate logic
> @@ -63,6 +72,7 @@ static __initdata struct kaslr_memory_region {
> } kaslr_regions[] = {
> { &page_offset_base, 64/* Maximum */ },
> { &vmalloc_base, VMALLOC_SIZE_TB },
> + { &vmemmap_base, 1 },
> };
>
> /* Get size in bytes used by the memory region */
> @@ -89,6 +99,18 @@ void __init kernel_randomize_memory(void)
> struct rnd_state rand_state;
> unsigned long remain_entropy;
>
> + /*
> + * All these BUILD_BUG_ON checks ensures the memory layout is
> + * consistent with the vaddr_start/vaddr_end variables.
> + */
> + BUILD_BUG_ON(vaddr_start >= vaddr_end);
> + BUILD_BUG_ON(config_enabled(CONFIG_X86_ESPFIX64) &&
> + vaddr_end >= EFI_VA_START);
> + BUILD_BUG_ON((config_enabled(CONFIG_X86_ESPFIX64) ||
> + config_enabled(CONFIG_EFI)) &&
> + vaddr_end >= __START_KERNEL_map);
> + BUILD_BUG_ON(vaddr_end > __START_KERNEL_map);
> +
> if (!kaslr_memory_enabled())
> return;
>
> --
> 2.8.0.rc3.226.g39d4020
>
^ permalink raw reply [flat|nested] 9+ messages in thread* Re: [PATCH] x86/mm: Enable KASLR for vmemmap memory region (x86_64)
2016-08-01 17:09 ` [kernel-hardening] " Thomas Garnier
@ 2016-08-02 8:14 ` Ingo Molnar
-1 siblings, 0 replies; 9+ messages in thread
From: Ingo Molnar @ 2016-08-02 8:14 UTC (permalink / raw)
To: Thomas Garnier
Cc: Thomas Gleixner, Ingo Molnar, H . Peter Anvin, Kees Cook, x86,
LKML, kernel-hardening
* Thomas Garnier <thgarnie@google.com> wrote:
> On Wed, Jul 27, 2016 at 8:59 AM, Thomas Garnier <thgarnie@google.com> wrote:
> > Add vmemmap in the list of randomized memory regions.
> >
> > The vmemmap region holds a representation of the physical memory (through
> > a struct page array). An attacker could use this region to disclose the
> > kernel memory layout (walking the page linked list).
> >
> > Signed-off-by: Thomas Garnier <thgarnie@google.com>
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> > ---
> > Missing patch didn't pick-up by the tip bot on KASLR memory randomization.
> > Resending after rebase on tip and tests as discussed with Ingo.
> > Based on tip 4bcc8cf6ab5932cbb2511c8e18065e61b069f21c
>
> Ingo: Any comment? Can you integrate it on tip?
>
> > ---
> > arch/x86/include/asm/kaslr.h | 1 +
> > arch/x86/include/asm/pgtable_64_types.h | 4 +++-
> > arch/x86/mm/kaslr.c | 24 +++++++++++++++++++++++-
> > 3 files changed, 27 insertions(+), 2 deletions(-)
After the merge window is over. There's no bad effect from the lack of this patch,
other than lower level of randomization of kernel virtual addresses, right?
Thanks,
Ingo
^ permalink raw reply [flat|nested] 9+ messages in thread
* [kernel-hardening] Re: [PATCH] x86/mm: Enable KASLR for vmemmap memory region (x86_64)
@ 2016-08-02 8:14 ` Ingo Molnar
0 siblings, 0 replies; 9+ messages in thread
From: Ingo Molnar @ 2016-08-02 8:14 UTC (permalink / raw)
To: Thomas Garnier
Cc: Thomas Gleixner, Ingo Molnar, H . Peter Anvin, Kees Cook, x86,
LKML, kernel-hardening
* Thomas Garnier <thgarnie@google.com> wrote:
> On Wed, Jul 27, 2016 at 8:59 AM, Thomas Garnier <thgarnie@google.com> wrote:
> > Add vmemmap in the list of randomized memory regions.
> >
> > The vmemmap region holds a representation of the physical memory (through
> > a struct page array). An attacker could use this region to disclose the
> > kernel memory layout (walking the page linked list).
> >
> > Signed-off-by: Thomas Garnier <thgarnie@google.com>
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> > ---
> > Missing patch didn't pick-up by the tip bot on KASLR memory randomization.
> > Resending after rebase on tip and tests as discussed with Ingo.
> > Based on tip 4bcc8cf6ab5932cbb2511c8e18065e61b069f21c
>
> Ingo: Any comment? Can you integrate it on tip?
>
> > ---
> > arch/x86/include/asm/kaslr.h | 1 +
> > arch/x86/include/asm/pgtable_64_types.h | 4 +++-
> > arch/x86/mm/kaslr.c | 24 +++++++++++++++++++++++-
> > 3 files changed, 27 insertions(+), 2 deletions(-)
After the merge window is over. There's no bad effect from the lack of this patch,
other than lower level of randomization of kernel virtual addresses, right?
Thanks,
Ingo
^ permalink raw reply [flat|nested] 9+ messages in thread
* Re: [PATCH] x86/mm: Enable KASLR for vmemmap memory region (x86_64)
2016-08-02 8:14 ` [kernel-hardening] " Ingo Molnar
@ 2016-08-02 14:24 ` Thomas Garnier
-1 siblings, 0 replies; 9+ messages in thread
From: Thomas Garnier @ 2016-08-02 14:24 UTC (permalink / raw)
To: Ingo Molnar
Cc: Thomas Gleixner, Ingo Molnar, H . Peter Anvin, Kees Cook, x86,
LKML, kernel-hardening
On Tue, Aug 2, 2016 at 1:14 AM, Ingo Molnar <mingo@kernel.org> wrote:
>
> * Thomas Garnier <thgarnie@google.com> wrote:
>
>> On Wed, Jul 27, 2016 at 8:59 AM, Thomas Garnier <thgarnie@google.com> wrote:
>> > Add vmemmap in the list of randomized memory regions.
>> >
>> > The vmemmap region holds a representation of the physical memory (through
>> > a struct page array). An attacker could use this region to disclose the
>> > kernel memory layout (walking the page linked list).
>> >
>> > Signed-off-by: Thomas Garnier <thgarnie@google.com>
>> > Signed-off-by: Kees Cook <keescook@chromium.org>
>> > ---
>> > Missing patch didn't pick-up by the tip bot on KASLR memory randomization.
>> > Resending after rebase on tip and tests as discussed with Ingo.
>> > Based on tip 4bcc8cf6ab5932cbb2511c8e18065e61b069f21c
>>
>> Ingo: Any comment? Can you integrate it on tip?
>>
>> > ---
>> > arch/x86/include/asm/kaslr.h | 1 +
>> > arch/x86/include/asm/pgtable_64_types.h | 4 +++-
>> > arch/x86/mm/kaslr.c | 24 +++++++++++++++++++++++-
>> > 3 files changed, 27 insertions(+), 2 deletions(-)
>
> After the merge window is over. There's no bad effect from the lack of this patch,
> other than lower level of randomization of kernel virtual addresses, right?
>
That's right, this change just enables randomization for vmemmap.
> Thanks,
>
> Ingo
^ permalink raw reply [flat|nested] 9+ messages in thread
* [kernel-hardening] Re: [PATCH] x86/mm: Enable KASLR for vmemmap memory region (x86_64)
@ 2016-08-02 14:24 ` Thomas Garnier
0 siblings, 0 replies; 9+ messages in thread
From: Thomas Garnier @ 2016-08-02 14:24 UTC (permalink / raw)
To: Ingo Molnar
Cc: Thomas Gleixner, Ingo Molnar, H . Peter Anvin, Kees Cook, x86,
LKML, kernel-hardening
On Tue, Aug 2, 2016 at 1:14 AM, Ingo Molnar <mingo@kernel.org> wrote:
>
> * Thomas Garnier <thgarnie@google.com> wrote:
>
>> On Wed, Jul 27, 2016 at 8:59 AM, Thomas Garnier <thgarnie@google.com> wrote:
>> > Add vmemmap in the list of randomized memory regions.
>> >
>> > The vmemmap region holds a representation of the physical memory (through
>> > a struct page array). An attacker could use this region to disclose the
>> > kernel memory layout (walking the page linked list).
>> >
>> > Signed-off-by: Thomas Garnier <thgarnie@google.com>
>> > Signed-off-by: Kees Cook <keescook@chromium.org>
>> > ---
>> > Missing patch didn't pick-up by the tip bot on KASLR memory randomization.
>> > Resending after rebase on tip and tests as discussed with Ingo.
>> > Based on tip 4bcc8cf6ab5932cbb2511c8e18065e61b069f21c
>>
>> Ingo: Any comment? Can you integrate it on tip?
>>
>> > ---
>> > arch/x86/include/asm/kaslr.h | 1 +
>> > arch/x86/include/asm/pgtable_64_types.h | 4 +++-
>> > arch/x86/mm/kaslr.c | 24 +++++++++++++++++++++++-
>> > 3 files changed, 27 insertions(+), 2 deletions(-)
>
> After the merge window is over. There's no bad effect from the lack of this patch,
> other than lower level of randomization of kernel virtual addresses, right?
>
That's right, this change just enables randomization for vmemmap.
> Thanks,
>
> Ingo
^ permalink raw reply [flat|nested] 9+ messages in thread
* [tip:x86/mm] x86/mm/64: Enable KASLR for vmemmap memory region
2016-07-27 15:59 ` [kernel-hardening] " Thomas Garnier
(?)
(?)
@ 2016-08-10 18:13 ` tip-bot for Thomas Garnier
-1 siblings, 0 replies; 9+ messages in thread
From: tip-bot for Thomas Garnier @ 2016-08-10 18:13 UTC (permalink / raw)
To: linux-tip-commits
Cc: jpoimboe, bp, linux-kernel, keescook, peterz, torvalds, tglx,
mingo, dvlasenk, brgerst, hpa, luto, thgarnie
Commit-ID: 25dfe4785332723f09311dcb7fd91015a60c022f
Gitweb: http://git.kernel.org/tip/25dfe4785332723f09311dcb7fd91015a60c022f
Author: Thomas Garnier <thgarnie@google.com>
AuthorDate: Wed, 27 Jul 2016 08:59:56 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 10 Aug 2016 16:10:06 +0200
x86/mm/64: Enable KASLR for vmemmap memory region
Add vmemmap in the list of randomized memory regions.
The vmemmap region holds a representation of the physical memory (through
a struct page array). An attacker could use this region to disclose the
kernel memory layout (walking the page linked list).
Signed-off-by: Thomas Garnier <thgarnie@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel-hardening@lists.openwall.com
Link: http://lkml.kernel.org/r/1469635196-122447-1-git-send-email-thgarnie@google.com
[ Minor edits. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
arch/x86/include/asm/kaslr.h | 1 +
arch/x86/include/asm/pgtable_64_types.h | 4 +++-
arch/x86/mm/kaslr.c | 26 ++++++++++++++++++++++++--
3 files changed, 28 insertions(+), 3 deletions(-)
diff --git a/arch/x86/include/asm/kaslr.h b/arch/x86/include/asm/kaslr.h
index 2674ee3..1052a79 100644
--- a/arch/x86/include/asm/kaslr.h
+++ b/arch/x86/include/asm/kaslr.h
@@ -6,6 +6,7 @@ unsigned long kaslr_get_random_long(const char *purpose);
#ifdef CONFIG_RANDOMIZE_MEMORY
extern unsigned long page_offset_base;
extern unsigned long vmalloc_base;
+extern unsigned long vmemmap_base;
void kernel_randomize_memory(void);
#else
diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
index 6fdef9e..3a26420 100644
--- a/arch/x86/include/asm/pgtable_64_types.h
+++ b/arch/x86/include/asm/pgtable_64_types.h
@@ -57,11 +57,13 @@ typedef struct { pteval_t pte; } pte_t;
#define MAXMEM _AC(__AC(1, UL) << MAX_PHYSMEM_BITS, UL)
#define VMALLOC_SIZE_TB _AC(32, UL)
#define __VMALLOC_BASE _AC(0xffffc90000000000, UL)
-#define VMEMMAP_START _AC(0xffffea0000000000, UL)
+#define __VMEMMAP_BASE _AC(0xffffea0000000000, UL)
#ifdef CONFIG_RANDOMIZE_MEMORY
#define VMALLOC_START vmalloc_base
+#define VMEMMAP_START vmemmap_base
#else
#define VMALLOC_START __VMALLOC_BASE
+#define VMEMMAP_START __VMEMMAP_BASE
#endif /* CONFIG_RANDOMIZE_MEMORY */
#define VMALLOC_END (VMALLOC_START + _AC((VMALLOC_SIZE_TB << 40) - 1, UL))
#define MODULES_VADDR (__START_KERNEL_map + KERNEL_IMAGE_SIZE)
diff --git a/arch/x86/mm/kaslr.c b/arch/x86/mm/kaslr.c
index ec8654f..aec03aa 100644
--- a/arch/x86/mm/kaslr.c
+++ b/arch/x86/mm/kaslr.c
@@ -40,17 +40,26 @@
* You need to add an if/def entry if you introduce a new memory region
* compatible with KASLR. Your entry must be in logical order with memory
* layout. For example, ESPFIX is before EFI because its virtual address is
- * before. You also need to add a BUILD_BUG_ON in kernel_randomize_memory to
+ * before. You also need to add a BUILD_BUG_ON() in kernel_randomize_memory() to
* ensure that this order is correct and won't be changed.
*/
static const unsigned long vaddr_start = __PAGE_OFFSET_BASE;
-static const unsigned long vaddr_end = VMEMMAP_START;
+
+#if defined(CONFIG_X86_ESPFIX64)
+static const unsigned long vaddr_end = ESPFIX_BASE_ADDR;
+#elif defined(CONFIG_EFI)
+static const unsigned long vaddr_end = EFI_VA_START;
+#else
+static const unsigned long vaddr_end = __START_KERNEL_map;
+#endif
/* Default values */
unsigned long page_offset_base = __PAGE_OFFSET_BASE;
EXPORT_SYMBOL(page_offset_base);
unsigned long vmalloc_base = __VMALLOC_BASE;
EXPORT_SYMBOL(vmalloc_base);
+unsigned long vmemmap_base = __VMEMMAP_BASE;
+EXPORT_SYMBOL(vmemmap_base);
/*
* Memory regions randomized by KASLR (except modules that use a separate logic
@@ -63,6 +72,7 @@ static __initdata struct kaslr_memory_region {
} kaslr_regions[] = {
{ &page_offset_base, 64/* Maximum */ },
{ &vmalloc_base, VMALLOC_SIZE_TB },
+ { &vmemmap_base, 1 },
};
/* Get size in bytes used by the memory region */
@@ -89,6 +99,18 @@ void __init kernel_randomize_memory(void)
struct rnd_state rand_state;
unsigned long remain_entropy;
+ /*
+ * All these BUILD_BUG_ON checks ensures the memory layout is
+ * consistent with the vaddr_start/vaddr_end variables.
+ */
+ BUILD_BUG_ON(vaddr_start >= vaddr_end);
+ BUILD_BUG_ON(config_enabled(CONFIG_X86_ESPFIX64) &&
+ vaddr_end >= EFI_VA_START);
+ BUILD_BUG_ON((config_enabled(CONFIG_X86_ESPFIX64) ||
+ config_enabled(CONFIG_EFI)) &&
+ vaddr_end >= __START_KERNEL_map);
+ BUILD_BUG_ON(vaddr_end > __START_KERNEL_map);
+
if (!kaslr_memory_enabled())
return;
^ permalink raw reply related [flat|nested] 9+ messages in thread