![Alexandre Ghiti](/assets/img/avatar_default.png)
mips uses a top-down layout by default that exactly fits the generic functions, so get rid of arch specific code and use the generic version by selecting ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT. As ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT selects ARCH_HAS_ELF_RANDOMIZE, use the generic version of arch_randomize_brk since it also fits. Note that this commit also removes the possibility for mips to have elf randomization and no MMU: without MMU, the security added by randomization is worth nothing. Link: http://lkml.kernel.org/r/20190730055113.23635-14-alex@ghiti.fr Signed-off-by: Alexandre Ghiti <alex@ghiti.fr> Acked-by: Paul Burton <paul.burton@mips.com> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Luis Chamberlain <mcgrof@kernel.org> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Christoph Hellwig <hch@lst.de> Cc: James Hogan <jhogan@kernel.org> Cc: Palmer Dabbelt <palmer@sifive.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>
130 lines
3.4 KiB
C
130 lines
3.4 KiB
C
/*
|
|
* This file is subject to the terms and conditions of the GNU General Public
|
|
* License. See the file "COPYING" in the main directory of this archive
|
|
* for more details.
|
|
*
|
|
* Copyright (C) 2011 Wind River Systems,
|
|
* written by Ralf Baechle <ralf@linux-mips.org>
|
|
*/
|
|
#include <linux/compiler.h>
|
|
#include <linux/elf-randomize.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/mman.h>
|
|
#include <linux/export.h>
|
|
#include <linux/personality.h>
|
|
#include <linux/random.h>
|
|
#include <linux/sched/signal.h>
|
|
#include <linux/sched/mm.h>
|
|
|
|
unsigned long shm_align_mask = PAGE_SIZE - 1; /* Sane caches */
|
|
EXPORT_SYMBOL(shm_align_mask);
|
|
|
|
#define COLOUR_ALIGN(addr, pgoff) \
|
|
((((addr) + shm_align_mask) & ~shm_align_mask) + \
|
|
(((pgoff) << PAGE_SHIFT) & shm_align_mask))
|
|
|
|
enum mmap_allocation_direction {UP, DOWN};
|
|
|
|
static unsigned long arch_get_unmapped_area_common(struct file *filp,
|
|
unsigned long addr0, unsigned long len, unsigned long pgoff,
|
|
unsigned long flags, enum mmap_allocation_direction dir)
|
|
{
|
|
struct mm_struct *mm = current->mm;
|
|
struct vm_area_struct *vma;
|
|
unsigned long addr = addr0;
|
|
int do_color_align;
|
|
struct vm_unmapped_area_info info;
|
|
|
|
if (unlikely(len > TASK_SIZE))
|
|
return -ENOMEM;
|
|
|
|
if (flags & MAP_FIXED) {
|
|
/* Even MAP_FIXED mappings must reside within TASK_SIZE */
|
|
if (TASK_SIZE - len < addr)
|
|
return -EINVAL;
|
|
|
|
/*
|
|
* We do not accept a shared mapping if it would violate
|
|
* cache aliasing constraints.
|
|
*/
|
|
if ((flags & MAP_SHARED) &&
|
|
((addr - (pgoff << PAGE_SHIFT)) & shm_align_mask))
|
|
return -EINVAL;
|
|
return addr;
|
|
}
|
|
|
|
do_color_align = 0;
|
|
if (filp || (flags & MAP_SHARED))
|
|
do_color_align = 1;
|
|
|
|
/* requesting a specific address */
|
|
if (addr) {
|
|
if (do_color_align)
|
|
addr = COLOUR_ALIGN(addr, pgoff);
|
|
else
|
|
addr = PAGE_ALIGN(addr);
|
|
|
|
vma = find_vma(mm, addr);
|
|
if (TASK_SIZE - len >= addr &&
|
|
(!vma || addr + len <= vm_start_gap(vma)))
|
|
return addr;
|
|
}
|
|
|
|
info.length = len;
|
|
info.align_mask = do_color_align ? (PAGE_MASK & shm_align_mask) : 0;
|
|
info.align_offset = pgoff << PAGE_SHIFT;
|
|
|
|
if (dir == DOWN) {
|
|
info.flags = VM_UNMAPPED_AREA_TOPDOWN;
|
|
info.low_limit = PAGE_SIZE;
|
|
info.high_limit = mm->mmap_base;
|
|
addr = vm_unmapped_area(&info);
|
|
|
|
if (!(addr & ~PAGE_MASK))
|
|
return addr;
|
|
|
|
/*
|
|
* A failed mmap() very likely causes application failure,
|
|
* so fall back to the bottom-up function here. This scenario
|
|
* can happen with large stack limits and large mmap()
|
|
* allocations.
|
|
*/
|
|
}
|
|
|
|
info.flags = 0;
|
|
info.low_limit = mm->mmap_base;
|
|
info.high_limit = TASK_SIZE;
|
|
return vm_unmapped_area(&info);
|
|
}
|
|
|
|
unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr0,
|
|
unsigned long len, unsigned long pgoff, unsigned long flags)
|
|
{
|
|
return arch_get_unmapped_area_common(filp,
|
|
addr0, len, pgoff, flags, UP);
|
|
}
|
|
|
|
/*
|
|
* There is no need to export this but sched.h declares the function as
|
|
* extern so making it static here results in an error.
|
|
*/
|
|
unsigned long arch_get_unmapped_area_topdown(struct file *filp,
|
|
unsigned long addr0, unsigned long len, unsigned long pgoff,
|
|
unsigned long flags)
|
|
{
|
|
return arch_get_unmapped_area_common(filp,
|
|
addr0, len, pgoff, flags, DOWN);
|
|
}
|
|
|
|
bool __virt_addr_valid(const volatile void *kaddr)
|
|
{
|
|
unsigned long vaddr = (unsigned long)kaddr;
|
|
|
|
if ((vaddr < PAGE_OFFSET) || (vaddr >= MAP_BASE))
|
|
return false;
|
|
|
|
return pfn_valid(PFN_DOWN(virt_to_phys(kaddr)));
|
|
}
|
|
EXPORT_SYMBOL_GPL(__virt_addr_valid);
|