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author | Kees Cook <keescook@chromium.org> | 2015-04-14 15:47:57 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2015-04-14 16:49:05 -0700 |
commit | 8e89a356feb6f196824a72101861d931a97ac2d2 (patch) | |
tree | a094206d40c115021bd0bc0f795091cee63b420f /arch/s390/mm | |
parent | ed6322746afb74c2509e2f3a6464182793b16eb9 (diff) | |
download | op-kernel-dev-8e89a356feb6f196824a72101861d931a97ac2d2.zip op-kernel-dev-8e89a356feb6f196824a72101861d931a97ac2d2.tar.gz |
s390: 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, and extracts the
checking of PF_RANDOMIZE.
Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/s390/mm')
-rw-r--r-- | arch/s390/mm/mmap.c | 34 |
1 files changed, 23 insertions, 11 deletions
diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c index 179a2c2..db57078 100644 --- a/arch/s390/mm/mmap.c +++ b/arch/s390/mm/mmap.c @@ -62,20 +62,18 @@ static inline int mmap_is_legacy(void) static unsigned long mmap_rnd(void) { - if (!(current->flags & PF_RANDOMIZE)) - return 0; if (is_32bit_task()) return (get_random_int() & 0x7ff) << PAGE_SHIFT; else return (get_random_int() & mmap_rnd_mask) << PAGE_SHIFT; } -static unsigned long mmap_base_legacy(void) +static unsigned long mmap_base_legacy(unsigned long rnd) { - return TASK_UNMAPPED_BASE + mmap_rnd(); + return TASK_UNMAPPED_BASE + rnd; } -static inline unsigned long mmap_base(void) +static inline unsigned long mmap_base(unsigned long rnd) { unsigned long gap = rlimit(RLIMIT_STACK); @@ -84,7 +82,7 @@ static inline unsigned long mmap_base(void) else if (gap > MAX_GAP) gap = MAX_GAP; gap &= PAGE_MASK; - return STACK_TOP - stack_maxrandom_size() - mmap_rnd() - gap; + return STACK_TOP - stack_maxrandom_size() - rnd - gap; } unsigned long @@ -187,7 +185,11 @@ unsigned long randomize_et_dyn(void) if (!is_32bit_task()) /* Align to 4GB */ base &= ~((1UL << 32) - 1); - return base + mmap_rnd(); + + if (current->flags & PF_RANDOMIZE) + base += mmap_rnd(); + + return base; } #ifndef CONFIG_64BIT @@ -198,15 +200,20 @@ unsigned long randomize_et_dyn(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 = mmap_base_legacy(); + mm->mmap_base = mmap_base_legacy(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; } } @@ -273,15 +280,20 @@ s390_get_unmapped_area_topdown(struct file *filp, const unsigned long addr, */ 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 = mmap_base_legacy(); + mm->mmap_base = mmap_base_legacy(random_factor); mm->get_unmapped_area = s390_get_unmapped_area; } else { - mm->mmap_base = mmap_base(); + mm->mmap_base = mmap_base(random_factor); mm->get_unmapped_area = s390_get_unmapped_area_topdown; } } |