Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 11977f85 authored by Kees Cook's avatar Kees Cook Committed by Trilok Soni
Browse files

s390: standardize mmap_rnd() usage 



In preparation for splitting out ET_DYN ASLR, this refactors the use of
mmap_rnd() to be used similarly to arm and x86, and extracts the
checking of PF_RANDOMIZE.

Change-Id: I6adb02b1f6bba6c9f416b4cc8287a21d05a22eb0
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Acked-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: default avatarIngo Molnar <mingo@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Git-commit: 8e89a356feb6f196824a72101861d931a97ac2d2
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: default avatarSe Wang (Patrick) Oh <sewango@codeaurora.org>
parent 8238053a

arch/s390/mm/mmap.c

+23 −11
Original line number Diff line number Diff line
@@ -62,20 +62,18 @@ static inline int mmap_is_legacy(void) 


static unsigned long mmap_rnd(void)

{

	if (!(current->flags & PF_RANDOMIZE))

		return 0;

	if (is_32bit_task())

		return (get_random_int() & 0x7ff) << PAGE_SHIFT;

	else

		return (get_random_int() & mmap_rnd_mask) << PAGE_SHIFT;

}



static unsigned long mmap_base_legacy(void)

static unsigned long mmap_base_legacy(unsigned long rnd)

{

	return TASK_UNMAPPED_BASE + mmap_rnd();

	return TASK_UNMAPPED_BASE + rnd;

}



static inline unsigned long mmap_base(void)

static inline unsigned long mmap_base(unsigned long rnd)

{

	unsigned long gap = rlimit(RLIMIT_STACK);
@@ -84,7 +82,7 @@ static inline unsigned long mmap_base(void) 
	else if (gap > MAX_GAP)

		gap = MAX_GAP;

	gap &= PAGE_MASK;

	return STACK_TOP - stack_maxrandom_size() - mmap_rnd() - gap;

	return STACK_TOP - stack_maxrandom_size() - rnd - gap;

}



unsigned long
@@ -187,7 +185,11 @@ unsigned long randomize_et_dyn(void) 
	if (!is_32bit_task())

		/* Align to 4GB */

		base &= ~((1UL << 32) - 1);

	return base + mmap_rnd();



	if (current->flags & PF_RANDOMIZE)

		base += mmap_rnd();



	return base;

}



#ifndef CONFIG_64BIT
@@ -198,15 +200,20 @@ unsigned long randomize_et_dyn(void) 
 */

void arch_pick_mmap_layout(struct mm_struct *mm)

{

	unsigned long random_factor = 0UL;



	if (current->flags & PF_RANDOMIZE)

		random_factor = mmap_rnd();



	/*

	 * Fall back to the standard layout if the personality

	 * bit is set, or if the expected stack growth is unlimited:

	 */

	if (mmap_is_legacy()) {

		mm->mmap_base = mmap_base_legacy();

		mm->mmap_base = mmap_base_legacy(random_factor);

		mm->get_unmapped_area = arch_get_unmapped_area;

	} else {

		mm->mmap_base = mmap_base();

		mm->mmap_base = mmap_base(random_factor);

		mm->get_unmapped_area = arch_get_unmapped_area_topdown;

	}

}
@@ -273,15 +280,20 @@ s390_get_unmapped_area_topdown(struct file *filp, const unsigned long addr, 
 */

void arch_pick_mmap_layout(struct mm_struct *mm)

{

	unsigned long random_factor = 0UL;



	if (current->flags & PF_RANDOMIZE)

		random_factor = mmap_rnd();



	/*

	 * Fall back to the standard layout if the personality

	 * bit is set, or if the expected stack growth is unlimited:

	 */

	if (mmap_is_legacy()) {

		mm->mmap_base = mmap_base_legacy();

		mm->mmap_base = mmap_base_legacy(random_factor);

		mm->get_unmapped_area = s390_get_unmapped_area;

	} else {

		mm->mmap_base = mmap_base();

		mm->mmap_base = mmap_base(random_factor);

		mm->get_unmapped_area = s390_get_unmapped_area_topdown;

	}

}