The patch titled
Subject: s390: standardize mmap_rnd() usage
has been added to the -mm tree. Its filename is
s390-standardize-mmap_rnd-usage.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/s390-standardize-mmap_rnd-usage.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/s390-standardize-mmap_rnd-usage.patch
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------------------------------------------------------
From: Kees Cook <keescook@xxxxxxxxxxxx>
Subject: 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.
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/s390/mm/mmap.c | 34 +++++++++++++++++++++++-----------
1 file changed, 23 insertions(+), 11 deletions(-)
diff -puN arch/s390/mm/mmap.c~s390-standardize-mmap_rnd-usage arch/s390/mm/mmap.c
--- a/arch/s390/mm/mmap.c~s390-standardize-mmap_rnd-usage
+++ a/arch/s390/mm/mmap.c
@@ -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(vo
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 fi
*/
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;
}
}
_
Patches currently in -mm which might be from keescook@xxxxxxxxxxxx are
arm-factor-out-mmap-aslr-into-mmap_rnd.patch
x86-standardize-mmap_rnd-usage.patch
arm64-standardize-mmap_rnd-usage.patch
mips-extract-logic-for-mmap_rnd.patch
powerpc-standardize-mmap_rnd-usage.patch
s390-standardize-mmap_rnd-usage.patch
mm-expose-arch_mmap_rnd-when-available.patch
s390-redefine-randomize_et_dyn-for-elf_et_dyn_base.patch
mm-split-et_dyn-aslr-from-mmap-aslr.patch
mm-fold-arch_randomize_brk-into-arch_has_elf_randomize.patch
lib-vsprintf-add-%pt-format-specifier.patch
linux-next.patch
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