The patch titled
Subject: powerpc: standardize mmap_rnd() usage
has been added to the -mm tree. Its filename is
powerpc-standardize-mmap_rnd-usage.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/powerpc-standardize-mmap_rnd-usage.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/powerpc-standardize-mmap_rnd-usage.patch
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------------------------------------------------------
From: Kees Cook <keescook@xxxxxxxxxxxx>
Subject: powerpc: 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.
(Can mmap ASLR be safely enabled in the legacy mmap case here? Other
archs use "mm->mmap_base = TASK_UNMAPPED_BASE + random_factor".)
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/mm/mmap.c | 26 +++++++++++++++-----------
1 file changed, 15 insertions(+), 11 deletions(-)
diff -puN arch/powerpc/mm/mmap.c~powerpc-standardize-mmap_rnd-usage arch/powerpc/mm/mmap.c
--- a/arch/powerpc/mm/mmap.c~powerpc-standardize-mmap_rnd-usage
+++ a/arch/powerpc/mm/mmap.c
@@ -55,19 +55,18 @@ static inline int mmap_is_legacy(void)
static unsigned long mmap_rnd(void)
{
- unsigned long rnd = 0;
+ unsigned long rnd;
+
+ /* 8MB for 32bit, 1GB for 64bit */
+ if (is_32bit_task())
+ rnd = (unsigned long)get_random_int() % (1<<(23-PAGE_SHIFT));
+ else
+ rnd = (unsigned long)get_random_int() % (1<<(30-PAGE_SHIFT));
- if (current->flags & PF_RANDOMIZE) {
- /* 8MB for 32bit, 1GB for 64bit */
- if (is_32bit_task())
- rnd = (long)(get_random_int() % (1<<(23-PAGE_SHIFT)));
- else
- rnd = (long)(get_random_int() % (1<<(30-PAGE_SHIFT)));
- }
return rnd << PAGE_SHIFT;
}
-static inline unsigned long mmap_base(void)
+static inline unsigned long mmap_base(unsigned long base)
{
unsigned long gap = rlimit(RLIMIT_STACK);
@@ -76,7 +75,7 @@ static inline unsigned long mmap_base(vo
else if (gap > MAX_GAP)
gap = MAX_GAP;
- return PAGE_ALIGN(TASK_SIZE - gap - mmap_rnd());
+ return PAGE_ALIGN(TASK_SIZE - gap - base);
}
/*
@@ -85,6 +84,11 @@ static inline unsigned long mmap_base(vo
*/
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:
@@ -93,7 +97,7 @@ void arch_pick_mmap_layout(struct mm_str
mm->mmap_base = TASK_UNMAPPED_BASE;
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;
}
}
_
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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