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Merge some improvements to the 32bit mmap randomisation from Kees Cook.

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This commit is contained in:
Dave Jones 2011-09-19 16:44:51 -04:00
parent 90792faae2
commit bd4ac46f66
3 changed files with 29 additions and 23 deletions
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3
kernel.spec
View File

@ -2067,6 +2067,9 @@ fi
# ||----w |
# || ||
%changelog
* Mon Sep 19 2011 Dave Jones <davej@redhat.com>
- Merge some improvements to the 32bit mmap randomisation from Kees Cook.
* Wed Sep 14 2011 Josh Boyer <jwboyer@redhat.com>
- Add patch to fix deadlock in ppc64 icswx (rhbz 737984)

27
linux-2.6-32bit-mmap-exec-randomization.patch
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@ -152,7 +152,7 @@ Main executable randomisation (PIE) : 12 bits (guessed)
struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
--- a/arch/x86/mm/mmap.c
+++ b/arch/x86/mm/mmap.c
@@ -124,13 +124,16 @@ static unsigned long mmap_legacy_base(void)
@@ -124,13 +124,19 @@ static unsigned long mmap_legacy_base(void)
*/
void arch_pick_mmap_layout(struct mm_struct *mm)
{
@ -163,9 +163,12 @@ Main executable randomisation (PIE) : 12 bits (guessed)
} else {
mm->mmap_base = mmap_base();
mm->get_unmapped_area = arch_get_unmapped_area_topdown;
+#ifdef CONFIG_X86_32
+ if (!(current->personality & READ_IMPLIES_EXEC)
+ && !(__supported_pte_mask & _PAGE_NX)
+ && mmap_is_ia32())
+ mm->get_unmapped_exec_area = arch_get_unmapped_exec_area;
+#endif
mm->unmap_area = arch_unmap_area_topdown;
}
}
@ -224,3 +227,25 @@ Main executable randomisation (PIE) : 12 bits (guessed)
if (new_addr & ~PAGE_MASK) {
ret = new_addr;
goto out;
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 57d1868..29c0c35 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -669,6 +669,16 @@ unsigned long arch_align_stack(unsigned long sp)
unsigned long arch_randomize_brk(struct mm_struct *mm)
{
unsigned long range_end = mm->brk + 0x02000000;
- return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
+ unsigned long bump = 0;
+#ifdef CONFIG_X86_32
+ /* in the case of NX emulation, shove the brk segment way out of the
+ way of the exec randomization area, since it can collide with
+ future allocations if not. */
+ if ( (mm->get_unmapped_exec_area == arch_get_unmapped_exec_area) &&
+ (mm->brk < 0x08000000) ) {
+ bump = (TASK_SIZE/6);
+ }
+#endif
+ return bump + (randomize_range(mm->brk, range_end, 0) ? : mm->brk);
}

22
linux-2.6-i386-nx-emulation.patch
View File

@ -592,25 +592,3 @@
mmu_notifier_invalidate_range_start(mm, start, end);
if (is_vm_hugetlb_page(vma))
hugetlb_change_protection(vma, start, end, vma->vm_page_prot);
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 57d1868..29c0c35 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -669,6 +669,16 @@ unsigned long arch_align_stack(unsigned long sp)
unsigned long arch_randomize_brk(struct mm_struct *mm)
{
unsigned long range_end = mm->brk + 0x02000000;
- return randomize_range(mm->brk, range_end, 0) ? : mm->brk;
+ unsigned long bump = 0;
+#ifdef CONFIG_X86_32
+ /* in the case of NX emulation, shove the brk segment way out of the
+ way of the exec randomization area, since it can collide with
+ future allocations if not. */
+ if ( (mm->get_unmapped_exec_area == arch_get_unmapped_exec_area) &&
+ (mm->brk < 0x08000000) ) {
+ bump = (TASK_SIZE/6);
+ }
+#endif
+ return bump + (randomize_range(mm->brk, range_end, 0) ? : mm->brk);
}