[PATCH] vm: fix vm_pgoff wrap in upward expansion
Paolo Pisati
paolo.pisati at canonical.com
Wed Oct 12 11:03:11 UTC 2011
From: Hugh Dickins <hughd at google.com>
vm: fix vm_pgoff wrap in upward expansion
Commit a626ca6a6564 ("vm: fix vm_pgoff wrap in stack expansion") fixed
the case of an expanding mapping causing vm_pgoff wrapping when you had
downward stack expansion. But there was another case where IA64 and
PA-RISC expand mappings: upward expansion.
This fixes that case too.
Signed-off-by: Hugh Dickins <hughd at google.com>
Cc: stable at kernel.org
Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
CVE-2011-2496
BugLink: http://bugs.launchpad.net/bugs/869243
(cherry picked from commit 42c36f63ac1366ab0ecc2d5717821362c259f517)
Signed-off-by: Paolo Pisati <paolo.pisati at canonical.com>
---
mm/mmap.c | 11 +++++++----
1 files changed, 7 insertions(+), 4 deletions(-)
diff --git a/mm/mmap.c b/mm/mmap.c
index 968c3e0..e9cc676 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1867,10 +1867,13 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
size = address - vma->vm_start;
grow = (address - vma->vm_end) >> PAGE_SHIFT;
- error = acct_stack_growth(vma, size, grow);
- if (!error) {
- vma->vm_end = address;
- perf_event_mmap(vma);
+ error = -ENOMEM;
+ if (vma->vm_pgoff + (size >> PAGE_SHIFT) >= vma->vm_pgoff) {
+ error = acct_stack_growth(vma, size, grow);
+ if (!error) {
+ vma->vm_end = address;
+ perf_event_mmap(vma);
+ }
}
}
vma_unlock_anon_vma(vma);
--
1.7.5.4
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