Commit 624483f3ea82598ab0f62f1bdb9177f531ab1892
Committed by
Linus Torvalds
Linus Torvalds
1 parent
951e273060
Exists in
ti-lsk-linux-4.1.y
and in
12 other branches
mm: rmap: fix use-after-free in __put_anon_vma
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> Cc: <stable@vger.kernel.org> # v3.0+ Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Showing 1 changed file with 1 additions and 2 deletions Side-by-side Diff
mm/rmap.c
| ... | ... | @@ -1564,10 +1564,9 @@ |
| 1564 | 1564 | { |
| 1565 | 1565 | struct anon_vma *root = anon_vma->root; |
| 1566 | 1566 | |
| 1567 | + anon_vma_free(anon_vma); | |
| 1567 | 1568 | if (root != anon_vma && atomic_dec_and_test(&root->refcount)) |
| 1568 | 1569 | anon_vma_free(root); |
| 1569 | - | |
| 1570 | - anon_vma_free(anon_vma); | |
| 1571 | 1570 | } |
| 1572 | 1571 | |
| 1573 | 1572 | static struct anon_vma *rmap_walk_anon_lock(struct page *page, |
