On Wed, Apr 17, 2019 at 12:33 AM Alexandre Ghiti <alex@xxxxxxxx> wrote: > > mips uses a top-down layout by default that fits the generic functions. > At the same time, this commit allows to fix problem uncovered > and not fixed for mips here: > https://www.mail-archive.com/linux-kernel@xxxxxxxxxxxxxxx/msg1429066.html > > Signed-off-by: Alexandre Ghiti <alex@xxxxxxxx> Acked-by: Kees Cook <keescook@xxxxxxxxxxxx> -Kees > --- > arch/mips/Kconfig | 1 + > arch/mips/include/asm/processor.h | 5 --- > arch/mips/mm/mmap.c | 67 ------------------------------- > 3 files changed, 1 insertion(+), 72 deletions(-) > > diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig > index 4a5f5b0ee9a9..ec2f07561e4d 100644 > --- a/arch/mips/Kconfig > +++ b/arch/mips/Kconfig > @@ -14,6 +14,7 @@ config MIPS > select ARCH_USE_CMPXCHG_LOCKREF if 64BIT > select ARCH_USE_QUEUED_RWLOCKS > select ARCH_USE_QUEUED_SPINLOCKS > + select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU > select ARCH_WANT_IPC_PARSE_VERSION > select BUILDTIME_EXTABLE_SORT > select CLONE_BACKWARDS > diff --git a/arch/mips/include/asm/processor.h b/arch/mips/include/asm/processor.h > index aca909bd7841..fba18d4a9190 100644 > --- a/arch/mips/include/asm/processor.h > +++ b/arch/mips/include/asm/processor.h > @@ -29,11 +29,6 @@ > > extern unsigned int vced_count, vcei_count; > > -/* > - * MIPS does have an arch_pick_mmap_layout() > - */ > -#define HAVE_ARCH_PICK_MMAP_LAYOUT 1 > - > #ifdef CONFIG_32BIT > #ifdef CONFIG_KVM_GUEST > /* User space process size is limited to 1GB in KVM Guest Mode */ > diff --git a/arch/mips/mm/mmap.c b/arch/mips/mm/mmap.c > index ffbe69f3a7d9..61e65a69bb09 100644 > --- a/arch/mips/mm/mmap.c > +++ b/arch/mips/mm/mmap.c > @@ -20,43 +20,6 @@ > unsigned long shm_align_mask = PAGE_SIZE - 1; /* Sane caches */ > EXPORT_SYMBOL(shm_align_mask); > > -/* gap between mmap and stack */ > -#define MIN_GAP (128*1024*1024UL) > -#define MAX_GAP ((STACK_TOP)/6*5) > -#define STACK_RND_MASK (0x7ff >> (PAGE_SHIFT - 12)) > - > -static int mmap_is_legacy(struct rlimit *rlim_stack) > -{ > - if (current->personality & ADDR_COMPAT_LAYOUT) > - return 1; > - > - if (rlim_stack->rlim_cur == RLIM_INFINITY) > - return 1; > - > - return sysctl_legacy_va_layout; > -} > - > -static unsigned long mmap_base(unsigned long rnd, struct rlimit *rlim_stack) > -{ > - unsigned long gap = rlim_stack->rlim_cur; > - 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) > - gap += pad; > - > - if (gap < MIN_GAP) > - gap = MIN_GAP; > - else if (gap > MAX_GAP) > - gap = MAX_GAP; > - > - return PAGE_ALIGN(STACK_TOP - gap - rnd); > -} > - > #define COLOUR_ALIGN(addr, pgoff) \ > ((((addr) + shm_align_mask) & ~shm_align_mask) + \ > (((pgoff) << PAGE_SHIFT) & shm_align_mask)) > @@ -154,36 +117,6 @@ unsigned long arch_get_unmapped_area_topdown(struct file *filp, > addr0, len, pgoff, flags, DOWN); > } > > -unsigned long arch_mmap_rnd(void) > -{ > - unsigned long rnd; > - > -#ifdef CONFIG_COMPAT > - if (TASK_IS_32BIT_ADDR) > - rnd = get_random_long() & ((1UL << mmap_rnd_compat_bits) - 1); > - else > -#endif /* CONFIG_COMPAT */ > - rnd = get_random_long() & ((1UL << mmap_rnd_bits) - 1); > - > - return rnd << PAGE_SHIFT; > -} > - > -void arch_pick_mmap_layout(struct mm_struct *mm, struct rlimit *rlim_stack) > -{ > - unsigned long random_factor = 0UL; > - > - if (current->flags & PF_RANDOMIZE) > - random_factor = arch_mmap_rnd(); > - > - if (mmap_is_legacy(rlim_stack)) { > - mm->mmap_base = TASK_UNMAPPED_BASE + random_factor; > - mm->get_unmapped_area = arch_get_unmapped_area; > - } else { > - mm->mmap_base = mmap_base(random_factor, rlim_stack); > - mm->get_unmapped_area = arch_get_unmapped_area_topdown; > - } > -} > - > static inline unsigned long brk_rnd(void) > { > unsigned long rnd = get_random_long(); > -- > 2.20.1 > -- Kees Cook
