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x86: PIE executable randomization
main executable of (specially compiled/linked -pie/-fpie) ET_DYN binaries onto a random address (in cases in which mmap() is allowed to perform a randomization). The code has been extraced from Ingo's exec-shield patch http://people.redhat.com/mingo/exec-shield/ [akpm@linux-foundation.org: fix used-uninitialsied warning] [kamezawa.hiroyu@jp.fujitsu.com: fixed ia32 ELF on x86_64 handling] Signed-off-by: Jiri Kosina <jkosina@suse.cz> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Roland McGrath <roland@redhat.com> Cc: Jakub Jelinek <jakub@redhat.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Jiri Kosina
Ingo Molnar
parent
82f74e7159
commit
cc503c1b43
@ -222,7 +222,7 @@ elf32_set_personality (void)
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}
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static unsigned long
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elf32_map (struct file *filep, unsigned long addr, struct elf_phdr *eppnt, int prot, int type)
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elf32_map (struct file *filep, unsigned long addr, struct elf_phdr *eppnt, int prot, int type, unsigned long unused)
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{
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unsigned long pgoff = (eppnt->p_vaddr) & ~IA32_PAGE_MASK;
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@ -12,6 +12,7 @@
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#include <linux/file.h>
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#include <linux/utsname.h>
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#include <linux/personality.h>
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#include <linux/random.h>
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#include <asm/uaccess.h>
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#include <asm/ia32.h>
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@ -65,6 +66,7 @@ static void find_start_end(unsigned long flags, unsigned long *begin,
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unsigned long *end)
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{
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if (!test_thread_flag(TIF_IA32) && (flags & MAP_32BIT)) {
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unsigned long new_begin;
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/* This is usually used needed to map code in small
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model, so it needs to be in the first 31bit. Limit
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it to that. This means we need to move the
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@ -74,6 +76,11 @@ static void find_start_end(unsigned long flags, unsigned long *begin,
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of playground for now. -AK */
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*begin = 0x40000000;
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*end = 0x80000000;
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if (current->flags & PF_RANDOMIZE) {
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new_begin = randomize_range(*begin, *begin + 0x02000000, 0);
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if (new_begin)
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*begin = new_begin;
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}
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} else {
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*begin = TASK_UNMAPPED_BASE;
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*end = TASK_SIZE;
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@ -143,6 +150,97 @@ full_search:
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}
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}
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unsigned long
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arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
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const unsigned long len, const unsigned long pgoff,
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const unsigned long flags)
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{
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struct vm_area_struct *vma;
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struct mm_struct *mm = current->mm;
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unsigned long addr = addr0;
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/* requested length too big for entire address space */
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if (len > TASK_SIZE)
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return -ENOMEM;
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if (flags & MAP_FIXED)
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return addr;
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/* for MAP_32BIT mappings we force the legact mmap base */
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if (!test_thread_flag(TIF_IA32) && (flags & MAP_32BIT))
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goto bottomup;
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/* requesting a specific address */
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if (addr) {
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addr = PAGE_ALIGN(addr);
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vma = find_vma(mm, addr);
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if (TASK_SIZE - len >= addr &&
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(!vma || addr + len <= vma->vm_start))
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return addr;
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}
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/* check if free_area_cache is useful for us */
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if (len <= mm->cached_hole_size) {
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mm->cached_hole_size = 0;
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mm->free_area_cache = mm->mmap_base;
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}
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/* either no address requested or can't fit in requested address hole */
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addr = mm->free_area_cache;
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/* make sure it can fit in the remaining address space */
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if (addr > len) {
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vma = find_vma(mm, addr-len);
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if (!vma || addr <= vma->vm_start)
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/* remember the address as a hint for next time */
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return (mm->free_area_cache = addr-len);
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}
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if (mm->mmap_base < len)
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goto bottomup;
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addr = mm->mmap_base-len;
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do {
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/*
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* Lookup failure means no vma is above this address,
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* else if new region fits below vma->vm_start,
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* return with success:
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*/
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vma = find_vma(mm, addr);
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if (!vma || addr+len <= vma->vm_start)
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/* remember the address as a hint for next time */
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return (mm->free_area_cache = addr);
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/* remember the largest hole we saw so far */
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if (addr + mm->cached_hole_size < vma->vm_start)
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mm->cached_hole_size = vma->vm_start - addr;
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/* try just below the current vma->vm_start */
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addr = vma->vm_start-len;
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} while (len < vma->vm_start);
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bottomup:
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/*
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* A failed mmap() very likely causes application failure,
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* so fall back to the bottom-up function here. This scenario
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* can happen with large stack limits and large mmap()
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* allocations.
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*/
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mm->cached_hole_size = ~0UL;
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mm->free_area_cache = TASK_UNMAPPED_BASE;
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addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
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/*
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* Restore the topdown base:
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*/
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mm->free_area_cache = mm->mmap_base;
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mm->cached_hole_size = ~0UL;
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return addr;
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}
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asmlinkage long sys_uname(struct new_utsname __user * name)
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{
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int err;
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@ -1,32 +1,117 @@
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/* Copyright 2005 Andi Kleen, SuSE Labs.
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* Licensed under GPL, v.2
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/*
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* linux/arch/x86-64/mm/mmap.c
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*
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* flexible mmap layout support
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*
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* Based on code by Ingo Molnar and Andi Kleen, copyrighted
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* as follows:
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*
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* Copyright 2003-2004 Red Hat Inc., Durham, North Carolina.
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* All Rights Reserved.
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* Copyright 2005 Andi Kleen, SUSE Labs.
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* Copyright 2007 Jiri Kosina, SUSE Labs.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#include <linux/personality.h>
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#include <linux/mm.h>
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#include <linux/sched.h>
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#include <linux/random.h>
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#include <linux/limits.h>
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#include <linux/sched.h>
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#include <asm/ia32.h>
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/* Notebook: move the mmap code from sys_x86_64.c over here. */
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/*
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* Top of mmap area (just below the process stack).
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*
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* Leave an at least ~128 MB hole.
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*/
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#define MIN_GAP (128*1024*1024)
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#define MAX_GAP (TASK_SIZE/6*5)
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void arch_pick_mmap_layout(struct mm_struct *mm)
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static inline unsigned long mmap_base(void)
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{
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unsigned long gap = current->signal->rlim[RLIMIT_STACK].rlim_cur;
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if (gap < MIN_GAP)
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gap = MIN_GAP;
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else if (gap > MAX_GAP)
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gap = MAX_GAP;
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return TASK_SIZE - (gap & PAGE_MASK);
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}
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static inline int mmap_is_32(void)
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{
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#ifdef CONFIG_IA32_EMULATION
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if (current_thread_info()->flags & _TIF_IA32)
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return ia32_pick_mmap_layout(mm);
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if (test_thread_flag(TIF_IA32))
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return 1;
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#endif
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mm->mmap_base = TASK_UNMAPPED_BASE;
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return 0;
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}
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static inline int mmap_is_legacy(void)
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{
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if (current->personality & ADDR_COMPAT_LAYOUT)
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return 1;
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if (current->signal->rlim[RLIMIT_STACK].rlim_cur == RLIM_INFINITY)
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return 1;
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return sysctl_legacy_va_layout;
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}
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/*
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* This function, called very early during the creation of a new
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* process VM image, sets up which VM layout function to use:
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*/
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void arch_pick_mmap_layout(struct mm_struct *mm)
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{
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int rnd = 0;
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if (current->flags & PF_RANDOMIZE) {
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/*
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* Add 28bit randomness which is about 40bits of
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* address space because mmap base has to be page
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* aligned. or ~1/128 of the total user VM (total
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* user address space is 47bits)
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* Add 28bit randomness which is about 40bits of address space
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* because mmap base has to be page aligned.
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* or ~1/128 of the total user VM
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* (total user address space is 47bits)
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*/
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unsigned rnd = get_random_int() & 0xfffffff;
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mm->mmap_base += ((unsigned long)rnd) << PAGE_SHIFT;
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rnd = get_random_int() & 0xfffffff;
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}
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/*
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* Fall back to the standard layout if the personality
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* bit is set, or if the expected stack growth is unlimited:
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*/
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if (mmap_is_32()) {
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#ifdef CONFIG_IA32_EMULATION
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/* ia32_pick_mmap_layout has its own. */
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return ia32_pick_mmap_layout(mm);
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#endif
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} else if(mmap_is_legacy()) {
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mm->mmap_base = TASK_UNMAPPED_BASE;
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mm->get_unmapped_area = arch_get_unmapped_area;
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mm->unmap_area = arch_unmap_area;
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} else {
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mm->mmap_base = mmap_base();
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mm->get_unmapped_area = arch_get_unmapped_area_topdown;
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mm->unmap_area = arch_unmap_area_topdown;
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if (current->flags & PF_RANDOMIZE)
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rnd = -rnd;
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}
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if (current->flags & PF_RANDOMIZE) {
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mm->mmap_base += ((long)rnd) << PAGE_SHIFT;
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}
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}
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107
fs/binfmt_elf.c
107
fs/binfmt_elf.c
@ -45,7 +45,7 @@
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static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs);
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static int load_elf_library(struct file *);
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static unsigned long elf_map (struct file *, unsigned long, struct elf_phdr *, int, int);
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static unsigned long elf_map (struct file *, unsigned long, struct elf_phdr *, int, int, unsigned long);
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/*
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* If we don't support core dumping, then supply a NULL so we
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@ -298,33 +298,70 @@ create_elf_tables(struct linux_binprm *bprm, struct elfhdr *exec,
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#ifndef elf_map
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static unsigned long elf_map(struct file *filep, unsigned long addr,
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struct elf_phdr *eppnt, int prot, int type)
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struct elf_phdr *eppnt, int prot, int type,
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unsigned long total_size)
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{
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unsigned long map_addr;
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unsigned long pageoffset = ELF_PAGEOFFSET(eppnt->p_vaddr);
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unsigned long size = eppnt->p_filesz + ELF_PAGEOFFSET(eppnt->p_vaddr);
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unsigned long off = eppnt->p_offset - ELF_PAGEOFFSET(eppnt->p_vaddr);
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addr = ELF_PAGESTART(addr);
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size = ELF_PAGEALIGN(size);
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down_write(¤t->mm->mmap_sem);
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/* mmap() will return -EINVAL if given a zero size, but a
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* segment with zero filesize is perfectly valid */
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if (eppnt->p_filesz + pageoffset)
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map_addr = do_mmap(filep, ELF_PAGESTART(addr),
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eppnt->p_filesz + pageoffset, prot, type,
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eppnt->p_offset - pageoffset);
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else
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map_addr = ELF_PAGESTART(addr);
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if (!size)
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return addr;
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down_write(¤t->mm->mmap_sem);
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/*
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* total_size is the size of the ELF (interpreter) image.
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* The _first_ mmap needs to know the full size, otherwise
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* randomization might put this image into an overlapping
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* position with the ELF binary image. (since size < total_size)
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* So we first map the 'big' image - and unmap the remainder at
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* the end. (which unmap is needed for ELF images with holes.)
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*/
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if (total_size) {
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total_size = ELF_PAGEALIGN(total_size);
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map_addr = do_mmap(filep, addr, total_size, prot, type, off);
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if (!BAD_ADDR(map_addr))
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do_munmap(current->mm, map_addr+size, total_size-size);
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} else
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map_addr = do_mmap(filep, addr, size, prot, type, off);
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up_write(¤t->mm->mmap_sem);
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return(map_addr);
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}
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#endif /* !elf_map */
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static unsigned long total_mapping_size(struct elf_phdr *cmds, int nr)
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{
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int i, first_idx = -1, last_idx = -1;
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for (i = 0; i < nr; i++) {
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if (cmds[i].p_type == PT_LOAD) {
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last_idx = i;
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if (first_idx == -1)
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first_idx = i;
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}
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}
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if (first_idx == -1)
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return 0;
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return cmds[last_idx].p_vaddr + cmds[last_idx].p_memsz -
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ELF_PAGESTART(cmds[first_idx].p_vaddr);
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}
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/* This is much more generalized than the library routine read function,
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so we keep this separate. Technically the library read function
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is only provided so that we can read a.out libraries that have
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an ELF header */
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static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
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struct file *interpreter, unsigned long *interp_load_addr)
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struct file *interpreter, unsigned long *interp_map_addr,
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unsigned long no_base)
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{
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struct elf_phdr *elf_phdata;
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struct elf_phdr *eppnt;
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@ -332,6 +369,7 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
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int load_addr_set = 0;
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unsigned long last_bss = 0, elf_bss = 0;
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unsigned long error = ~0UL;
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unsigned long total_size;
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int retval, i, size;
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/* First of all, some simple consistency checks */
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@ -370,6 +408,12 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
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goto out_close;
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}
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total_size = total_mapping_size(elf_phdata, interp_elf_ex->e_phnum);
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if (!total_size) {
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error = -EINVAL;
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goto out_close;
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}
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eppnt = elf_phdata;
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for (i = 0; i < interp_elf_ex->e_phnum; i++, eppnt++) {
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if (eppnt->p_type == PT_LOAD) {
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@ -387,9 +431,14 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
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vaddr = eppnt->p_vaddr;
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if (interp_elf_ex->e_type == ET_EXEC || load_addr_set)
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elf_type |= MAP_FIXED;
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else if (no_base && interp_elf_ex->e_type == ET_DYN)
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load_addr = -vaddr;
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map_addr = elf_map(interpreter, load_addr + vaddr,
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eppnt, elf_prot, elf_type);
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eppnt, elf_prot, elf_type, total_size);
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total_size = 0;
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if (!*interp_map_addr)
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*interp_map_addr = map_addr;
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error = map_addr;
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if (BAD_ADDR(map_addr))
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goto out_close;
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@ -455,8 +504,7 @@ static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
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goto out_close;
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}
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*interp_load_addr = load_addr;
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error = ((unsigned long)interp_elf_ex->e_entry) + load_addr;
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error = load_addr;
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out_close:
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kfree(elf_phdata);
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@ -553,7 +601,8 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
|
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int elf_exec_fileno;
|
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int retval, i;
|
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unsigned int size;
|
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unsigned long elf_entry, interp_load_addr = 0;
|
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unsigned long elf_entry;
|
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unsigned long interp_load_addr = 0;
|
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unsigned long start_code, end_code, start_data, end_data;
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unsigned long reloc_func_desc = 0;
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char passed_fileno[6];
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@ -825,9 +874,7 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
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current->mm->start_stack = bprm->p;
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|
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/* Now we do a little grungy work by mmaping the ELF image into
|
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the correct location in memory. At this point, we assume that
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the image should be loaded at fixed address, not at a variable
|
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address. */
|
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the correct location in memory. */
|
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for(i = 0, elf_ppnt = elf_phdata;
|
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i < loc->elf_ex.e_phnum; i++, elf_ppnt++) {
|
||||
int elf_prot = 0, elf_flags;
|
||||
@ -881,11 +928,15 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
|
||||
* default mmap base, as well as whatever program they
|
||||
* might try to exec. This is because the brk will
|
||||
* follow the loader, and is not movable. */
|
||||
#ifdef CONFIG_X86
|
||||
load_bias = 0;
|
||||
#else
|
||||
load_bias = ELF_PAGESTART(ELF_ET_DYN_BASE - vaddr);
|
||||
#endif
|
||||
}
|
||||
|
||||
error = elf_map(bprm->file, load_bias + vaddr, elf_ppnt,
|
||||
elf_prot, elf_flags);
|
||||
elf_prot, elf_flags,0);
|
||||
if (BAD_ADDR(error)) {
|
||||
send_sig(SIGKILL, current, 0);
|
||||
retval = IS_ERR((void *)error) ?
|
||||
@ -961,13 +1012,25 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
|
||||
}
|
||||
|
||||
if (elf_interpreter) {
|
||||
if (interpreter_type == INTERPRETER_AOUT)
|
||||
if (interpreter_type == INTERPRETER_AOUT) {
|
||||
elf_entry = load_aout_interp(&loc->interp_ex,
|
||||
interpreter);
|
||||
else
|
||||
} else {
|
||||
unsigned long uninitialized_var(interp_map_addr);
|
||||
|
||||
elf_entry = load_elf_interp(&loc->interp_elf_ex,
|
||||
interpreter,
|
||||
&interp_load_addr);
|
||||
&interp_map_addr,
|
||||
load_bias);
|
||||
if (!IS_ERR((void *)elf_entry)) {
|
||||
/*
|
||||
* load_elf_interp() returns relocation
|
||||
* adjustment
|
||||
*/
|
||||
interp_load_addr = elf_entry;
|
||||
elf_entry += loc->interp_elf_ex.e_entry;
|
||||
}
|
||||
}
|
||||
if (BAD_ADDR(elf_entry)) {
|
||||
force_sig(SIGSEGV, current);
|
||||
retval = IS_ERR((void *)elf_entry) ?
|
||||
|
||||
@ -413,6 +413,7 @@ pte_t *lookup_address(unsigned long addr);
|
||||
remap_pfn_range(vma, vaddr, pfn, size, prot)
|
||||
|
||||
#define HAVE_ARCH_UNMAPPED_AREA
|
||||
#define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN
|
||||
|
||||
#define pgtable_cache_init() do { } while (0)
|
||||
#define check_pgt_cache() do { } while (0)
|
||||
|
||||
Loading…
Reference in New Issue
Block a user