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Diffstat (limited to 'arch/arm64/mm/mmap.c')
-rw-r--r--arch/arm64/mm/mmap.c20
1 files changed, 12 insertions, 8 deletions
diff --git a/arch/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c
index 54922d1275b8..ed177475dd8c 100644
--- a/arch/arm64/mm/mmap.c
+++ b/arch/arm64/mm/mmap.c
@@ -47,17 +47,16 @@ static int mmap_is_legacy(void)
return sysctl_legacy_va_layout;
}
-static unsigned long mmap_rnd(void)
+unsigned long arch_mmap_rnd(void)
{
- unsigned long rnd = 0;
+ unsigned long rnd;
- if (current->flags & PF_RANDOMIZE)
- rnd = (long)get_random_int() & STACK_RND_MASK;
+ rnd = (unsigned long)get_random_int() & STACK_RND_MASK;
return rnd << PAGE_SHIFT;
}
-static unsigned long mmap_base(void)
+static unsigned long mmap_base(unsigned long rnd)
{
unsigned long gap = rlimit(RLIMIT_STACK);
@@ -66,7 +65,7 @@ static unsigned long mmap_base(void)
else if (gap > MAX_GAP)
gap = MAX_GAP;
- return PAGE_ALIGN(STACK_TOP - gap - mmap_rnd());
+ return PAGE_ALIGN(STACK_TOP - gap - rnd);
}
/*
@@ -75,15 +74,20 @@ static unsigned long mmap_base(void)
*/
void arch_pick_mmap_layout(struct mm_struct *mm)
{
+ unsigned long random_factor = 0UL;
+
+ if (current->flags & PF_RANDOMIZE)
+ random_factor = arch_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 = TASK_UNMAPPED_BASE;
+ mm->mmap_base = TASK_UNMAPPED_BASE + 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;
}
}