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| author |   Kees Cook <keescook@chromium.org> | 2015-04-14 15:47:51 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2015-04-14 16:49:05 -0700 |
| commit | 1f0569df0b0285e7ec2432d804a4921b06a61618 (patch) | |
| tree | 04f5a3abc1ec569dfa39f679a3f13a7d55692cc9 /arch/mips/mm/mmap.c | |
| parent | arm64: standardize mmap_rnd() usage (diff) | |
| download | linux-dev-1f0569df0b0285e7ec2432d804a4921b06a61618.tar.xz linux-dev-1f0569df0b0285e7ec2432d804a4921b06a61618.zip | |
mips: extract logic for mmap_rnd()
In preparation for splitting out ET_DYN ASLR, extract the mmap ASLR
selection into a separate function.
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to '')
| -rw-r--r-- | arch/mips/mm/mmap.c | 24 |
1 files changed, 16 insertions, 8 deletions
diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c index f1baadd56e82..9a4f1f5c1f0e 100644 --- a/arch/mips/mm/mmap.c +++ b/arch/mips/mm/mmap.c @@ -142,18 +142,26 @@ unsigned long arch_get_unmapped_area_topdown(struct file *filp, addr0, len, pgoff, flags, DOWN); } +static unsigned long mmap_rnd(void) +{ + unsigned long rnd; + + rnd = (unsigned long)get_random_int(); + rnd <<= PAGE_SHIFT; + if (TASK_IS_32BIT_ADDR) + rnd &= 0xfffffful; + else + rnd &= 0xffffffful; + + return rnd; +} + void arch_pick_mmap_layout(struct mm_struct *mm) { unsigned long random_factor = 0UL; - if (current->flags & PF_RANDOMIZE) { - random_factor = get_random_int(); - random_factor = random_factor << PAGE_SHIFT; - if (TASK_IS_32BIT_ADDR) - random_factor &= 0xfffffful; - else - random_factor &= 0xffffffful; - } + if (current->flags & PF_RANDOMIZE) + random_factor = mmap_rnd(); if (mmap_is_legacy()) { mm->mmap_base = TASK_UNMAPPED_BASE + random_factor; |