Re: [PATCH v3 08/11] mips: Properly account for stack randomization and stack guard gap

2019-04-19 Thread Alex Ghiti 

On 4/18/19 5:27 PM, Paul Burton wrote:

Hi Alexandre,

On Wed, Apr 17, 2019 at 01:22:44AM -0400, Alexandre Ghiti wrote:

This commit takes care of stack randomization and stack guard gap when
computing mmap base address and checks if the task asked for randomization.
This fixes the problem uncovered and not fixed for mips here:
https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1429066.html

Signed-off-by: Alexandre Ghiti 

For patches 8-10:

 Acked-by: Paul Burton 

Thanks for improving this,



Thank you for your time,


Alex



 Paul


---
  arch/mips/mm/mmap.c | 14 --
  1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c
index 2f616ebeb7e0..3ff82c6f7e24 100644
--- a/arch/mips/mm/mmap.c
+++ b/arch/mips/mm/mmap.c
@@ -21,8 +21,9 @@ unsigned long shm_align_mask = PAGE_SIZE - 1; /* Sane caches 
*/
  EXPORT_SYMBOL(shm_align_mask);
  
  /* gap between mmap and stack */

-#define MIN_GAP (128*1024*1024UL)
-#define MAX_GAP ((TASK_SIZE)/6*5)
+#define MIN_GAP(128*1024*1024UL)
+#define MAX_GAP((TASK_SIZE)/6*5)
+#define STACK_RND_MASK (0x7ff >> (PAGE_SHIFT - 12))
  
  static int mmap_is_legacy(struct rlimit *rlim_stack)

  {
@@ -38,6 +39,15 @@ static int mmap_is_legacy(struct rlimit *rlim_stack)
  static unsigned long mmap_base(unsigned long rnd, struct rlimit *rlim_stack)
  {
unsigned long gap = rlim_stack->rlim_cur;
+   unsigned long pad = stack_guard_gap;
+
+   /* Account for stack randomization if necessary */
+   if (current->flags & PF_RANDOMIZE)
+   pad += (STACK_RND_MASK << PAGE_SHIFT);
+
+   /* Values close to RLIM_INFINITY can overflow. */
+   if (gap + pad > gap)
+   gap += pad;
  
  	if (gap < MIN_GAP)

gap = MIN_GAP;
--
2.20.1


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Re: [PATCH v3 08/11] mips: Properly account for stack randomization and stack guard gap

2019-04-18 Thread Paul Burton 
Hi Alexandre,

On Wed, Apr 17, 2019 at 01:22:44AM -0400, Alexandre Ghiti wrote:
> This commit takes care of stack randomization and stack guard gap when
> computing mmap base address and checks if the task asked for randomization.
> This fixes the problem uncovered and not fixed for mips here:
> https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1429066.html
> 
> Signed-off-by: Alexandre Ghiti 

For patches 8-10:

Acked-by: Paul Burton 

Thanks for improving this,

Paul

> ---
>  arch/mips/mm/mmap.c | 14 --
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c
> index 2f616ebeb7e0..3ff82c6f7e24 100644
> --- a/arch/mips/mm/mmap.c
> +++ b/arch/mips/mm/mmap.c
> @@ -21,8 +21,9 @@ unsigned long shm_align_mask = PAGE_SIZE - 1;   /* Sane 
> caches */
>  EXPORT_SYMBOL(shm_align_mask);
>  
>  /* gap between mmap and stack */
> -#define MIN_GAP (128*1024*1024UL)
> -#define MAX_GAP ((TASK_SIZE)/6*5)
> +#define MIN_GAP  (128*1024*1024UL)
> +#define MAX_GAP  ((TASK_SIZE)/6*5)
> +#define STACK_RND_MASK   (0x7ff >> (PAGE_SHIFT - 12))
>  
>  static int mmap_is_legacy(struct rlimit *rlim_stack)
>  {
> @@ -38,6 +39,15 @@ static int mmap_is_legacy(struct rlimit *rlim_stack)
>  static unsigned long mmap_base(unsigned long rnd, struct rlimit *rlim_stack)
>  {
>   unsigned long gap = rlim_stack->rlim_cur;
> + unsigned long pad = stack_guard_gap;
> +
> + /* Account for stack randomization if necessary */
> + if (current->flags & PF_RANDOMIZE)
> + pad += (STACK_RND_MASK << PAGE_SHIFT);
> +
> + /* Values close to RLIM_INFINITY can overflow. */
> + if (gap + pad > gap)
> + gap += pad;
>  
>   if (gap < MIN_GAP)
>   gap = MIN_GAP;
> -- 
> 2.20.1
>

Re: [PATCH v3 08/11] mips: Properly account for stack randomization and stack guard gap

2019-04-18 Thread Alex Ghiti 

On 4/18/19 1:30 AM, Kees Cook wrote:

On Wed, Apr 17, 2019 at 12:31 AM Alexandre Ghiti  wrote:

This commit takes care of stack randomization and stack guard gap when
computing mmap base address and checks if the task asked for randomization.
This fixes the problem uncovered and not fixed for mips here:
https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1429066.html

same URL change here please...


Signed-off-by: Alexandre Ghiti 

Acked-by: Kees Cook 



Thanks !




-Kees


---
  arch/mips/mm/mmap.c | 14 --
  1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c
index 2f616ebeb7e0..3ff82c6f7e24 100644
--- a/arch/mips/mm/mmap.c
+++ b/arch/mips/mm/mmap.c
@@ -21,8 +21,9 @@ unsigned long shm_align_mask = PAGE_SIZE - 1; /* Sane caches 
*/
  EXPORT_SYMBOL(shm_align_mask);

  /* gap between mmap and stack */
-#define MIN_GAP (128*1024*1024UL)
-#define MAX_GAP ((TASK_SIZE)/6*5)
+#define MIN_GAP(128*1024*1024UL)
+#define MAX_GAP((TASK_SIZE)/6*5)
+#define STACK_RND_MASK (0x7ff >> (PAGE_SHIFT - 12))

  static int mmap_is_legacy(struct rlimit *rlim_stack)
  {
@@ -38,6 +39,15 @@ static int mmap_is_legacy(struct rlimit *rlim_stack)
  static unsigned long mmap_base(unsigned long rnd, struct rlimit *rlim_stack)
  {
 unsigned long gap = rlim_stack->rlim_cur;
+   unsigned long pad = stack_guard_gap;
+
+   /* Account for stack randomization if necessary */
+   if (current->flags & PF_RANDOMIZE)
+   pad += (STACK_RND_MASK << PAGE_SHIFT);
+
+   /* Values close to RLIM_INFINITY can overflow. */
+   if (gap + pad > gap)
+   gap += pad;

 if (gap < MIN_GAP)
 gap = MIN_GAP;
--
2.20.1

Re: [PATCH v3 08/11] mips: Properly account for stack randomization and stack guard gap

2019-04-17 Thread Kees Cook 
On Wed, Apr 17, 2019 at 12:31 AM Alexandre Ghiti  wrote:
>
> This commit takes care of stack randomization and stack guard gap when
> computing mmap base address and checks if the task asked for randomization.
> This fixes the problem uncovered and not fixed for mips here:
> https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1429066.html

same URL change here please...

>
> Signed-off-by: Alexandre Ghiti 

Acked-by: Kees Cook 

-Kees

> ---
>  arch/mips/mm/mmap.c | 14 --
>  1 file changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c
> index 2f616ebeb7e0..3ff82c6f7e24 100644
> --- a/arch/mips/mm/mmap.c
> +++ b/arch/mips/mm/mmap.c
> @@ -21,8 +21,9 @@ unsigned long shm_align_mask = PAGE_SIZE - 1; /* Sane 
> caches */
>  EXPORT_SYMBOL(shm_align_mask);
>
>  /* gap between mmap and stack */
> -#define MIN_GAP (128*1024*1024UL)
> -#define MAX_GAP ((TASK_SIZE)/6*5)
> +#define MIN_GAP(128*1024*1024UL)
> +#define MAX_GAP((TASK_SIZE)/6*5)
> +#define STACK_RND_MASK (0x7ff >> (PAGE_SHIFT - 12))
>
>  static int mmap_is_legacy(struct rlimit *rlim_stack)
>  {
> @@ -38,6 +39,15 @@ static int mmap_is_legacy(struct rlimit *rlim_stack)
>  static unsigned long mmap_base(unsigned long rnd, struct rlimit *rlim_stack)
>  {
> unsigned long gap = rlim_stack->rlim_cur;
> +   unsigned long pad = stack_guard_gap;
> +
> +   /* Account for stack randomization if necessary */
> +   if (current->flags & PF_RANDOMIZE)
> +   pad += (STACK_RND_MASK << PAGE_SHIFT);
> +
> +   /* Values close to RLIM_INFINITY can overflow. */
> +   if (gap + pad > gap)
> +   gap += pad;
>
> if (gap < MIN_GAP)
> gap = MIN_GAP;
> --
> 2.20.1
>

-- 
Kees Cook

[PATCH v3 08/11] mips: Properly account for stack randomization and stack guard gap

2019-04-16 Thread Alexandre Ghiti 
This commit takes care of stack randomization and stack guard gap when
computing mmap base address and checks if the task asked for randomization.
This fixes the problem uncovered and not fixed for mips here:
https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1429066.html

Signed-off-by: Alexandre Ghiti 
---
 arch/mips/mm/mmap.c | 14 --
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c
index 2f616ebeb7e0..3ff82c6f7e24 100644
--- a/arch/mips/mm/mmap.c
+++ b/arch/mips/mm/mmap.c
@@ -21,8 +21,9 @@ unsigned long shm_align_mask = PAGE_SIZE - 1; /* Sane caches 
*/
 EXPORT_SYMBOL(shm_align_mask);
 
 /* gap between mmap and stack */
-#define MIN_GAP (128*1024*1024UL)
-#define MAX_GAP ((TASK_SIZE)/6*5)
+#define MIN_GAP(128*1024*1024UL)
+#define MAX_GAP((TASK_SIZE)/6*5)
+#define STACK_RND_MASK (0x7ff >> (PAGE_SHIFT - 12))
 
 static int mmap_is_legacy(struct rlimit *rlim_stack)
 {
@@ -38,6 +39,15 @@ static int mmap_is_legacy(struct rlimit *rlim_stack)
 static unsigned long mmap_base(unsigned long rnd, struct rlimit *rlim_stack)
 {
unsigned long gap = rlim_stack->rlim_cur;
+   unsigned long pad = stack_guard_gap;
+
+   /* Account for stack randomization if necessary */
+   if (current->flags & PF_RANDOMIZE)
+   pad += (STACK_RND_MASK << PAGE_SHIFT);
+
+   /* Values close to RLIM_INFINITY can overflow. */
+   if (gap + pad > gap)
+   gap += pad;
 
if (gap < MIN_GAP)
gap = MIN_GAP;
-- 
2.20.1