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| author |   Alexandre Ghiti <alex@ghiti.fr> | 2019-09-23 15:38:43 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2019-09-24 15:54:11 -0700 |
| commit | e8d54b62c55ab6201de6d195fc2c276294c1f6ae (patch) | |
| tree | e1370bd9c98312edc3f1353b1af4f4f4ad7c3e47 /arch/arm64 | |
| parent | arm64: make use of is_compat_task instead of hardcoding this test (diff) | |
| download | linux-dev-e8d54b62c55ab6201de6d195fc2c276294c1f6ae.tar.xz linux-dev-e8d54b62c55ab6201de6d195fc2c276294c1f6ae.zip | |
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@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>
Diffstat (limited to 'arch/arm64')
| -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 bb0140afed66..e4acaead67de 100644 --- a/arch/arm64/mm/mmap.c +++ b/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) |