The patch titled
Subject: arm64: standardize mmap_rnd() usage
has been added to the -mm tree. Its filename is
arm64-standardize-mmap_rnd-usage.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/arm64-standardize-mmap_rnd-usage.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/arm64-standardize-mmap_rnd-usage.patch
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------------------------------------------------------
From: Kees Cook <keescook@xxxxxxxxxxxx>
Subject: arm64: 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. This additionally enables
mmap ASLR on legacy mmap layouts, which appeared to be missing on arm64,
and was already supported on arm. Additionally removes a copy/pasted
declaration of an unused function.
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arm64/include/asm/elf.h | 1 -
arch/arm64/mm/mmap.c | 18 +++++++++++-------
2 files changed, 11 insertions(+), 8 deletions(-)
diff -puN arch/arm64/include/asm/elf.h~arm64-standardize-mmap_rnd-usage arch/arm64/include/asm/elf.h
--- a/arch/arm64/include/asm/elf.h~arm64-standardize-mmap_rnd-usage
+++ a/arch/arm64/include/asm/elf.h
@@ -125,7 +125,6 @@ typedef struct user_fpsimd_state elf_fpr
* the loader. We need to make sure that it is out of the way of the program
* that it will "exec", and that there is sufficient room for the brk.
*/
-extern unsigned long randomize_et_dyn(unsigned long base);
#define ELF_ET_DYN_BASE (2 * TASK_SIZE_64 / 3)
/*
diff -puN arch/arm64/mm/mmap.c~arm64-standardize-mmap_rnd-usage arch/arm64/mm/mmap.c
--- a/arch/arm64/mm/mmap.c~arm64-standardize-mmap_rnd-usage
+++ a/arch/arm64/mm/mmap.c
@@ -49,15 +49,14 @@ static int mmap_is_legacy(void)
static unsigned long 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 base)
{
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 - base);
}
/*
@@ -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 = 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;
}
}
_
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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