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Fix address wrapping in stack expansion code.

This commit is contained in:
Chuck Ebbert 2011-05-21 13:13:37 -04:00
parent 7e51f2f324
commit fcf9248627
2 changed files with 57 additions and 0 deletions
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7
kernel.spec
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@ -855,6 +855,9 @@ Patch13970: cifs-add-fallback-in-is_path_accessible-for-old-servers.patch
# cve-2011-1770
Patch13980: dccp-handle-invalid-feature-options-length.patch
# the rest of the pgoff wrap fix
Patch13990: vm-fix-vm_pgoff-wrap-in-stack-expansion.patch
%endif
BuildRoot: %{_tmppath}/kernel-%{KVERREL}-root
@ -1609,6 +1612,9 @@ ApplyPatch cifs-add-fallback-in-is_path_accessible-for-old-servers.patch
# cve-2011-1770
ApplyPatch dccp-handle-invalid-feature-options-length.patch
# the rest of the pgoff wrap fix
ApplyPatch vm-fix-vm_pgoff-wrap-in-stack-expansion.patch
# END OF PATCH APPLICATIONS
%endif
@ -2198,6 +2204,7 @@ fi
* Fri May 20 2011 Chuck Ebbert <cebbert@redhat.com> 2.6.35.13-92
- Add the rest of the fix for bug #704059
- dccp: handle invalid feature options length (CVE-2011-1770)
- Fix address wrapping in stack expansion code.
* Wed May 18 2011 Chuck Ebbert <cebbert@redhat.com>
- Fix cifs bug in 2.6.35.13 with old Windows servers (#704125)

50
vm-fix-vm_pgoff-wrap-in-stack-expansion.patch Normal file
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@ -0,0 +1,50 @@
From a626ca6a656450e9f4df91d0dda238fff23285f4 Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Wed, 13 Apr 2011 08:07:28 -0700
Subject: vm: fix vm_pgoff wrap in stack expansion
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
From: Linus Torvalds <torvalds@linux-foundation.org>
commit a626ca6a656450e9f4df91d0dda238fff23285f4 upstream.
Commit 982134ba6261 ("mm: avoid wrapping vm_pgoff in mremap()") fixed
the case of a expanding mapping causing vm_pgoff wrapping when you used
mremap. But there was another case where we expand mappings hiding in
plain sight: the automatic stack expansion.
This fixes that case too.
This one also found by Robert Święcki, using his nasty system call
fuzzer tool. Good job.
Reported-and-tested-by: Robert Święcki <robert@swiecki.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---
mm/mmap.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1814,10 +1814,13 @@ static int expand_downwards(struct vm_ar
size = vma->vm_end - address;
grow = (vma->vm_start - address) >> PAGE_SHIFT;
- error = acct_stack_growth(vma, size, grow);
- if (!error) {
- vma->vm_start = address;
- vma->vm_pgoff -= grow;
+ error = -ENOMEM;
+ if (grow <= vma->vm_pgoff) {
+ error = acct_stack_growth(vma, size, grow);
+ if (!error) {
+ vma->vm_start = address;
+ vma->vm_pgoff -= grow;
+ }
}
}
vma_unlock_anon_vma(vma);