Messages in this thread | | | Subject | Re: [PATCH v3 10/11] mips: Use generic mmap top-down layout | From | Alex Ghiti <> | Date | Thu, 18 Apr 2019 02:08:31 -0400 |
| |
On 4/18/19 1:31 AM, Kees Cook wrote: > On Wed, Apr 17, 2019 at 12:33 AM Alexandre Ghiti <alex@ghiti.fr> 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@vger.kernel.org/msg1429066.html >> >> Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> > Acked-by: Kees Cook <keescook@chromium.org>
Thanks !
> > -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 >> >
| |