2005-04-17 00:20:36 +02:00
|
|
|
/*
|
|
|
|
* flexible mmap layout support
|
|
|
|
*
|
|
|
|
* Copyright 2003-2004 Red Hat Inc., Durham, North Carolina.
|
|
|
|
* All Rights Reserved.
|
|
|
|
*
|
|
|
|
* This program is free software; you can redistribute it and/or modify
|
|
|
|
* it under the terms of the GNU General Public License as published by
|
|
|
|
* the Free Software Foundation; either version 2 of the License, or
|
|
|
|
* (at your option) any later version.
|
|
|
|
*
|
|
|
|
* This program is distributed in the hope that it will be useful,
|
|
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
|
|
* GNU General Public License for more details.
|
|
|
|
*
|
|
|
|
* You should have received a copy of the GNU General Public License
|
|
|
|
* along with this program; if not, write to the Free Software
|
|
|
|
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
|
|
|
*
|
|
|
|
*
|
|
|
|
* Started by Ingo Molnar <mingo@elte.hu>
|
|
|
|
*/
|
|
|
|
|
|
|
|
#include <linux/personality.h>
|
|
|
|
#include <linux/mm.h>
|
2009-02-22 02:50:01 +01:00
|
|
|
#include <linux/random.h>
|
2017-02-08 18:51:30 +01:00
|
|
|
#include <linux/sched/signal.h>
|
2017-02-08 18:51:31 +01:00
|
|
|
#include <linux/sched/mm.h>
|
2016-01-06 01:45:51 +01:00
|
|
|
#include <linux/elf-randomize.h>
|
2016-04-29 15:26:11 +02:00
|
|
|
#include <linux/security.h>
|
|
|
|
#include <linux/mman.h>
|
2005-04-17 00:20:36 +02:00
|
|
|
|
|
|
|
/*
|
|
|
|
* Top of mmap area (just below the process stack).
|
|
|
|
*
|
2009-02-22 02:50:06 +01:00
|
|
|
* Leave at least a ~128 MB hole on 32bit applications.
|
|
|
|
*
|
|
|
|
* On 64bit applications we randomise the stack by 1GB so we need to
|
|
|
|
* space our mmap start address by a further 1GB, otherwise there is a
|
|
|
|
* chance the mmap area will end up closer to the stack than our ulimit
|
|
|
|
* requires.
|
2005-04-17 00:20:36 +02:00
|
|
|
*/
|
2009-02-22 02:50:06 +01:00
|
|
|
#define MIN_GAP32 (128*1024*1024)
|
|
|
|
#define MIN_GAP64 ((128 + 1024)*1024*1024UL)
|
|
|
|
#define MIN_GAP ((is_32bit_task()) ? MIN_GAP32 : MIN_GAP64)
|
2005-04-17 00:20:36 +02:00
|
|
|
#define MAX_GAP (TASK_SIZE/6*5)
|
|
|
|
|
2009-02-22 02:50:00 +01:00
|
|
|
static inline int mmap_is_legacy(void)
|
|
|
|
{
|
|
|
|
if (current->personality & ADDR_COMPAT_LAYOUT)
|
|
|
|
return 1;
|
|
|
|
|
2010-01-06 06:24:31 +01:00
|
|
|
if (rlimit(RLIMIT_STACK) == RLIM_INFINITY)
|
2009-02-22 02:50:00 +01:00
|
|
|
return 1;
|
|
|
|
|
|
|
|
return sysctl_legacy_va_layout;
|
|
|
|
}
|
|
|
|
|
2015-04-15 00:48:00 +02:00
|
|
|
unsigned long arch_mmap_rnd(void)
|
2009-02-22 02:50:01 +01:00
|
|
|
{
|
2017-04-20 16:36:20 +02:00
|
|
|
unsigned long shift, rnd;
|
2015-04-15 00:47:54 +02:00
|
|
|
|
2017-04-20 16:36:20 +02:00
|
|
|
shift = mmap_rnd_bits;
|
|
|
|
#ifdef CONFIG_COMPAT
|
2015-04-15 00:47:54 +02:00
|
|
|
if (is_32bit_task())
|
2017-04-20 16:36:20 +02:00
|
|
|
shift = mmap_rnd_compat_bits;
|
|
|
|
#endif
|
2017-04-25 12:49:24 +02:00
|
|
|
rnd = get_random_long() % (1ul << shift);
|
2009-02-22 02:50:01 +01:00
|
|
|
|
2011-10-17 15:05:23 +02:00
|
|
|
return rnd << PAGE_SHIFT;
|
2009-02-22 02:50:01 +01:00
|
|
|
}
|
|
|
|
|
2015-04-15 00:47:54 +02:00
|
|
|
static inline unsigned long mmap_base(unsigned long rnd)
|
2005-04-17 00:20:36 +02:00
|
|
|
{
|
2010-01-06 06:24:31 +01:00
|
|
|
unsigned long gap = rlimit(RLIMIT_STACK);
|
2005-04-17 00:20:36 +02:00
|
|
|
|
|
|
|
if (gap < MIN_GAP)
|
|
|
|
gap = MIN_GAP;
|
|
|
|
else if (gap > MAX_GAP)
|
|
|
|
gap = MAX_GAP;
|
|
|
|
|
2017-03-30 13:05:21 +02:00
|
|
|
return PAGE_ALIGN(DEFAULT_MAP_WINDOW - gap - rnd);
|
2005-04-17 00:20:36 +02:00
|
|
|
}
|
|
|
|
|
2016-04-29 15:26:11 +02:00
|
|
|
#ifdef CONFIG_PPC_RADIX_MMU
|
|
|
|
/*
|
|
|
|
* Same function as generic code used only for radix, because we don't need to overload
|
|
|
|
* the generic one. But we will have to duplicate, because hash select
|
|
|
|
* HAVE_ARCH_UNMAPPED_AREA
|
|
|
|
*/
|
|
|
|
static unsigned long
|
|
|
|
radix__arch_get_unmapped_area(struct file *filp, unsigned long addr,
|
|
|
|
unsigned long len, unsigned long pgoff,
|
|
|
|
unsigned long flags)
|
|
|
|
{
|
|
|
|
struct mm_struct *mm = current->mm;
|
|
|
|
struct vm_area_struct *vma;
|
|
|
|
struct vm_unmapped_area_info info;
|
|
|
|
|
2017-04-18 09:01:27 +02:00
|
|
|
if (unlikely(addr > mm->context.addr_limit &&
|
|
|
|
mm->context.addr_limit != TASK_SIZE))
|
2017-03-30 13:05:21 +02:00
|
|
|
mm->context.addr_limit = TASK_SIZE;
|
|
|
|
|
2017-04-13 21:18:21 +02:00
|
|
|
if (len > mm->task_size - mmap_min_addr)
|
2016-04-29 15:26:11 +02:00
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
if (flags & MAP_FIXED)
|
|
|
|
return addr;
|
|
|
|
|
|
|
|
if (addr) {
|
|
|
|
addr = PAGE_ALIGN(addr);
|
|
|
|
vma = find_vma(mm, addr);
|
2017-04-13 21:18:21 +02:00
|
|
|
if (mm->task_size - len >= addr && addr >= mmap_min_addr &&
|
2016-04-29 15:26:11 +02:00
|
|
|
(!vma || addr + len <= vma->vm_start))
|
|
|
|
return addr;
|
|
|
|
}
|
|
|
|
|
|
|
|
info.flags = 0;
|
|
|
|
info.length = len;
|
|
|
|
info.low_limit = mm->mmap_base;
|
|
|
|
info.align_mask = 0;
|
2017-03-30 13:05:21 +02:00
|
|
|
|
|
|
|
if (unlikely(addr > DEFAULT_MAP_WINDOW))
|
|
|
|
info.high_limit = mm->context.addr_limit;
|
|
|
|
else
|
|
|
|
info.high_limit = DEFAULT_MAP_WINDOW;
|
|
|
|
|
2016-04-29 15:26:11 +02:00
|
|
|
return vm_unmapped_area(&info);
|
|
|
|
}
|
|
|
|
|
|
|
|
static unsigned long
|
|
|
|
radix__arch_get_unmapped_area_topdown(struct file *filp,
|
|
|
|
const unsigned long addr0,
|
|
|
|
const unsigned long len,
|
|
|
|
const unsigned long pgoff,
|
|
|
|
const unsigned long flags)
|
|
|
|
{
|
|
|
|
struct vm_area_struct *vma;
|
|
|
|
struct mm_struct *mm = current->mm;
|
|
|
|
unsigned long addr = addr0;
|
|
|
|
struct vm_unmapped_area_info info;
|
|
|
|
|
2017-04-18 09:01:27 +02:00
|
|
|
if (unlikely(addr > mm->context.addr_limit &&
|
|
|
|
mm->context.addr_limit != TASK_SIZE))
|
2017-03-30 13:05:21 +02:00
|
|
|
mm->context.addr_limit = TASK_SIZE;
|
|
|
|
|
2016-04-29 15:26:11 +02:00
|
|
|
/* requested length too big for entire address space */
|
2017-04-13 21:18:21 +02:00
|
|
|
if (len > mm->task_size - mmap_min_addr)
|
2016-04-29 15:26:11 +02:00
|
|
|
return -ENOMEM;
|
|
|
|
|
|
|
|
if (flags & MAP_FIXED)
|
|
|
|
return addr;
|
|
|
|
|
|
|
|
/* requesting a specific address */
|
|
|
|
if (addr) {
|
|
|
|
addr = PAGE_ALIGN(addr);
|
|
|
|
vma = find_vma(mm, addr);
|
2017-04-13 21:18:21 +02:00
|
|
|
if (mm->task_size - len >= addr && addr >= mmap_min_addr &&
|
2016-04-29 15:26:11 +02:00
|
|
|
(!vma || addr + len <= vma->vm_start))
|
|
|
|
return addr;
|
|
|
|
}
|
|
|
|
|
|
|
|
info.flags = VM_UNMAPPED_AREA_TOPDOWN;
|
|
|
|
info.length = len;
|
|
|
|
info.low_limit = max(PAGE_SIZE, mmap_min_addr);
|
|
|
|
info.high_limit = mm->mmap_base;
|
|
|
|
info.align_mask = 0;
|
2017-03-30 13:05:21 +02:00
|
|
|
|
|
|
|
if (addr > DEFAULT_MAP_WINDOW)
|
|
|
|
info.high_limit += mm->context.addr_limit - DEFAULT_MAP_WINDOW;
|
|
|
|
|
2016-04-29 15:26:11 +02:00
|
|
|
addr = vm_unmapped_area(&info);
|
2017-03-30 13:05:21 +02:00
|
|
|
if (!(addr & ~PAGE_MASK))
|
|
|
|
return addr;
|
|
|
|
VM_BUG_ON(addr != -ENOMEM);
|
2016-04-29 15:26:11 +02:00
|
|
|
|
|
|
|
/*
|
|
|
|
* 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.
|
|
|
|
*/
|
2017-03-30 13:05:21 +02:00
|
|
|
return radix__arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
|
2016-04-29 15:26:11 +02:00
|
|
|
}
|
|
|
|
|
|
|
|
static void radix__arch_pick_mmap_layout(struct mm_struct *mm,
|
|
|
|
unsigned long random_factor)
|
|
|
|
{
|
|
|
|
if (mmap_is_legacy()) {
|
|
|
|
mm->mmap_base = TASK_UNMAPPED_BASE;
|
|
|
|
mm->get_unmapped_area = radix__arch_get_unmapped_area;
|
|
|
|
} else {
|
|
|
|
mm->mmap_base = mmap_base(random_factor);
|
|
|
|
mm->get_unmapped_area = radix__arch_get_unmapped_area_topdown;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
#else
|
|
|
|
/* dummy */
|
|
|
|
extern void radix__arch_pick_mmap_layout(struct mm_struct *mm,
|
|
|
|
unsigned long random_factor);
|
|
|
|
#endif
|
2005-04-17 00:20:36 +02:00
|
|
|
/*
|
|
|
|
* This function, called very early during the creation of a new
|
|
|
|
* process VM image, sets up which VM layout function to use:
|
|
|
|
*/
|
|
|
|
void arch_pick_mmap_layout(struct mm_struct *mm)
|
|
|
|
{
|
2015-04-15 00:47:54 +02:00
|
|
|
unsigned long random_factor = 0UL;
|
|
|
|
|
|
|
|
if (current->flags & PF_RANDOMIZE)
|
2015-04-15 00:48:00 +02:00
|
|
|
random_factor = arch_mmap_rnd();
|
2015-04-15 00:47:54 +02:00
|
|
|
|
2016-04-29 15:26:11 +02:00
|
|
|
if (radix_enabled())
|
|
|
|
return radix__arch_pick_mmap_layout(mm, random_factor);
|
2005-04-17 00:20:36 +02:00
|
|
|
/*
|
|
|
|
* 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 = TASK_UNMAPPED_BASE;
|
|
|
|
mm->get_unmapped_area = arch_get_unmapped_area;
|
|
|
|
} else {
|
2015-04-15 00:47:54 +02:00
|
|
|
mm->mmap_base = mmap_base(random_factor);
|
2005-04-17 00:20:36 +02:00
|
|
|
mm->get_unmapped_area = arch_get_unmapped_area_topdown;
|
|
|
|
}
|
|
|
|
}
|