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authorHeiko Carstens <heiko.carstens@de.ibm.com>2013-11-12 15:07:55 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-11-13 12:09:08 +0900
commit7aba842f08bb9e8485ff40067dc090ada4c7f575 (patch)
treece123c31ecd534df33925b0b9861ead2df75c209
parent4e99b02131b280b064d30a5926ef1c4763f3097b (diff)
downloadop-kernel-dev-7aba842f08bb9e8485ff40067dc090ada4c7f575.zip
op-kernel-dev-7aba842f08bb9e8485ff40067dc090ada4c7f575.tar.gz
s390/mmap: randomize mmap base for bottom up direction
Implement mmap base randomization for the bottom up direction, so ASLR works for both mmap layouts on s390. See also commit df54d6fa5427 ("x86 get_unmapped_area(): use proper mmap base for bottom-up direction"). Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Radu Caragea <sinaelgl@gmail.com> Cc: Michel Lespinasse <walken@google.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--arch/s390/mm/mmap.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c
index 6bcb045..9b436c2 100644
--- a/arch/s390/mm/mmap.c
+++ b/arch/s390/mm/mmap.c
@@ -64,6 +64,11 @@ static unsigned long mmap_rnd(void)
return (get_random_int() & 0x7ffUL) << PAGE_SHIFT;
}
+static unsigned long mmap_base_legacy(void)
+{
+ return TASK_UNMAPPED_BASE + mmap_rnd();
+}
+
static inline unsigned long mmap_base(void)
{
unsigned long gap = rlimit(RLIMIT_STACK);
@@ -89,7 +94,7 @@ void arch_pick_mmap_layout(struct mm_struct *mm)
* bit is set, or if the expected stack growth is unlimited:
*/
if (mmap_is_legacy()) {
- mm->mmap_base = TASK_UNMAPPED_BASE;
+ mm->mmap_base = mmap_base_legacy();
mm->get_unmapped_area = arch_get_unmapped_area;
} else {
mm->mmap_base = mmap_base();
@@ -164,7 +169,7 @@ void arch_pick_mmap_layout(struct mm_struct *mm)
* bit is set, or if the expected stack growth is unlimited:
*/
if (mmap_is_legacy()) {
- mm->mmap_base = TASK_UNMAPPED_BASE;
+ mm->mmap_base = mmap_base_legacy();
mm->get_unmapped_area = s390_get_unmapped_area;
} else {
mm->mmap_base = mmap_base();
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