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| author | Alexandre Ghiti <alex@ghiti.fr> | 2019-09-24 01:38:43 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-10-07 19:57:17 +0300 |
| commit | e1b391abbfceed3f703447a86c8c13d83555f6cc (patch) | |
| tree | 527b2345c9a18ef950508f7454dd4770fb3ee826 | |
| parent | 30ab799e758e9c00bb575e51d831c314f661abfb (diff) | |
| download | linux-e1b391abbfceed3f703447a86c8c13d83555f6cc.tar.xz | |
arm64: consider stack randomization for mmap base only when necessary
[ Upstream commit e8d54b62c55ab6201de6d195fc2c276294c1f6ae ]
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@ghiti.fr
Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Luis Chamberlain <mcgrof@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: James Hogan <jhogan@kernel.org>
Cc: Palmer Dabbelt <palmer@sifive.com>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | arch/arm64/mm/mmap.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/arch/arm64/mm/mmap.c b/arch/arm64/mm/mmap.c index 842c8a5fcd53..157f2caa1351 100644 --- a/arch/arm64/mm/mmap.c +++ b/arch/arm64/mm/mmap.c @@ -65,7 +65,11 @@ 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) |