The patch titled
Subject: arm64: consider stack randomization for mmap base only when necessary
has been added to the -mm tree. Its filename is
arm64-consider-stack-randomization-for-mmap-base-only-when-necessary.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/arm64-consider-stack-randomization-for-mmap-base-only-when-necessary.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/arm64-consider-stack-randomization-for-mmap-base-only-when-necessary.patch
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The -mm tree is included into linux-next and is updated
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------------------------------------------------------
From: Alexandre Ghiti <alex@xxxxxxxx>
Subject: arm64: consider stack randomization for mmap base only when necessary
Do not offset mmap base address because of stack randomization if current
task does not want randomization. Note that x86 already implements this
behaviour.
Link: http://lkml.kernel.org/r/20190730055113.23635-4-alex@xxxxxxxx
Signed-off-by: Alexandre Ghiti <alex@xxxxxxxx>
Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Acked-by: Kees Cook <keescook@xxxxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Cc: Albert Ou <aou@xxxxxxxxxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: James Hogan <jhogan@xxxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxx>
Cc: Paul Burton <paul.burton@xxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arm64/mm/mmap.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
--- a/arch/arm64/mm/mmap.c~arm64-consider-stack-randomization-for-mmap-base-only-when-necessary
+++ a/arch/arm64/mm/mmap.c
@@ -54,7 +54,11 @@ unsigned long arch_mmap_rnd(void)
static unsigned long mmap_base(unsigned long rnd, struct rlimit *rlim_stack)
{
unsigned long gap = rlim_stack->rlim_cur;
- unsigned long pad = (STACK_RND_MASK << PAGE_SHIFT) + stack_guard_gap;
+ unsigned long pad = stack_guard_gap;
+
+ /* Account for stack randomization if necessary */
+ if (current->flags & PF_RANDOMIZE)
+ pad += (STACK_RND_MASK << PAGE_SHIFT);
/* Values close to RLIM_INFINITY can overflow. */
if (gap + pad > gap)
_
Patches currently in -mm which might be from alex@xxxxxxxx are
mm-fs-move-randomize_stack_top-from-fs-to-mm.patch
arm64-make-use-of-is_compat_task-instead-of-hardcoding-this-test.patch
arm64-consider-stack-randomization-for-mmap-base-only-when-necessary.patch
arm64-mm-move-generic-mmap-layout-functions-to-mm.patch
arm64-mm-make-randomization-selected-by-generic-topdown-mmap-layout.patch
arm-properly-account-for-stack-randomization-and-stack-guard-gap.patch
arm-use-stack_top-when-computing-mmap-base-address.patch
arm-use-generic-mmap-top-down-layout-and-brk-randomization.patch
mips-properly-account-for-stack-randomization-and-stack-guard-gap.patch
mips-use-stack_top-when-computing-mmap-base-address.patch
mips-adjust-brk-randomization-offset-to-fit-generic-version.patch
mips-replace-arch-specific-way-to-determine-32bit-task-with-generic-version.patch
mips-use-generic-mmap-top-down-layout-and-brk-randomization.patch
riscv-make-mmap-allocation-top-down-by-default.patch
