Commit 3ed6413483c7a43b9d38111357ce99afab441717
Committed by
Greg Kroah-Hartman
Greg Kroah-Hartman
1 parent
395982ce12
Exists in
ti-linux-3.14.y
and in
2 other branches
mm: rmap: fix use-after-free in __put_anon_vma
commit 624483f3ea82598ab0f62f1bdb9177f531ab1892 upstream. While working address sanitizer for kernel I've discovered use-after-free bug in __put_anon_vma. For the last anon_vma, anon_vma->root freed before child anon_vma. Later in anon_vma_free(anon_vma) we are referencing to already freed anon_vma->root to check rwsem. This fixes it by freeing the child anon_vma before freeing anon_vma->root. Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Showing 1 changed file with 1 additions and 2 deletions Side-by-side Diff
mm/rmap.c
| ... | ... | @@ -1554,10 +1554,9 @@ |
| 1554 | 1554 | { |
| 1555 | 1555 | struct anon_vma *root = anon_vma->root; |
| 1556 | 1556 | |
| 1557 | + anon_vma_free(anon_vma); | |
| 1557 | 1558 | if (root != anon_vma && atomic_dec_and_test(&root->refcount)) |
| 1558 | 1559 | anon_vma_free(root); |
| 1559 | - | |
| 1560 | - anon_vma_free(anon_vma); | |
| 1561 | 1560 | } |
| 1562 | 1561 | |
| 1563 | 1562 | static struct anon_vma *rmap_walk_anon_lock(struct page *page, |