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authorKees Cook <keescook@chromium.org>2015-04-15 01:47:51 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2015-04-15 02:49:05 +0300
commit1f0569df0b0285e7ec2432d804a4921b06a61618 (patch)
tree04f5a3abc1ec569dfa39f679a3f13a7d55692cc9 /arch
parentdd04cff1dceab18226853b555cf07914648a235f (diff)
downloadlinux-1f0569df0b0285e7ec2432d804a4921b06a61618.tar.xz
mips: extract logic for mmap_rnd()
In preparation for splitting out ET_DYN ASLR, extract the mmap ASLR selection into a separate function. Signed-off-by: Kees Cook <keescook@chromium.org> Reviewed-by: Ingo Molnar <mingo@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/mips/mm/mmap.c24
1 files changed, 16 insertions, 8 deletions
diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c
index f1baadd56e82..9a4f1f5c1f0e 100644
--- a/arch/mips/mm/mmap.c
+++ b/arch/mips/mm/mmap.c
@@ -142,18 +142,26 @@ unsigned long arch_get_unmapped_area_topdown(struct file *filp,
addr0, len, pgoff, flags, DOWN);
}
+static unsigned long mmap_rnd(void)
+{
+ unsigned long rnd;
+
+ rnd = (unsigned long)get_random_int();
+ rnd <<= PAGE_SHIFT;
+ if (TASK_IS_32BIT_ADDR)
+ rnd &= 0xfffffful;
+ else
+ rnd &= 0xffffffful;
+
+ return rnd;
+}
+
void arch_pick_mmap_layout(struct mm_struct *mm)
{
unsigned long random_factor = 0UL;
- if (current->flags & PF_RANDOMIZE) {
- random_factor = get_random_int();
- random_factor = random_factor << PAGE_SHIFT;
- if (TASK_IS_32BIT_ADDR)
- random_factor &= 0xfffffful;
- else
- random_factor &= 0xffffffful;
- }
+ if (current->flags & PF_RANDOMIZE)
+ random_factor = mmap_rnd();
if (mmap_is_legacy()) {
mm->mmap_base = TASK_UNMAPPED_BASE + random_factor;