* [PATCH v2] mm: rmap: fix use-after-free in __put_anon_vma [not found] <20140606115620.GS3213@twins.programming.kicks-ass.net> @ 2014-06-06 15:09 ` Andrey Ryabinin 2014-06-06 15:30 ` Peter Zijlstra 2014-06-07 21:50 ` David Rientjes 0 siblings, 2 replies; 3+ messages in thread From: Andrey Ryabinin @ 2014-06-06 15:09 UTC (permalink / raw) To: Andrew Morton, Linus Torvalds, Peter Zijlstra Cc: linux-mm, linux-kernel, koct9i, Andrey Ryabinin, stable 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 patch puts freeing of child anon_vma before freeing of anon_vma->root. Cc: <stable@vger.kernel.org> # v3.0+ Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com> --- Changes since v1: - just made it more simple following Peter's suggestion mm/rmap.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/mm/rmap.c b/mm/rmap.c index 9c3e773..cb5f70a 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1564,10 +1564,10 @@ void __put_anon_vma(struct anon_vma *anon_vma) { struct anon_vma *root = anon_vma->root; + anon_vma_free(anon_vma); + if (root != anon_vma && atomic_dec_and_test(&root->refcount)) anon_vma_free(root); - - anon_vma_free(anon_vma); } static struct anon_vma *rmap_walk_anon_lock(struct page *page, -- 1.8.5.5 ^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v2] mm: rmap: fix use-after-free in __put_anon_vma 2014-06-06 15:09 ` [PATCH v2] mm: rmap: fix use-after-free in __put_anon_vma Andrey Ryabinin @ 2014-06-06 15:30 ` Peter Zijlstra 2014-06-07 21:50 ` David Rientjes 1 sibling, 0 replies; 3+ messages in thread From: Peter Zijlstra @ 2014-06-06 15:30 UTC (permalink / raw) To: Andrey Ryabinin Cc: Andrew Morton, Linus Torvalds, linux-mm, linux-kernel, koct9i, stable, Hugh Dickins On Fri, Jun 06, 2014 at 07:09:30PM +0400, Andrey Ryabinin wrote: > 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 patch puts freeing of child anon_vma before freeing of anon_vma->root. > > Cc: <stable@vger.kernel.org> # v3.0+ Acked-by: Peter Zijlstra <peterz@infradead.org> > Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com> > --- > > Changes since v1: > - just made it more simple following Peter's suggestion > > mm/rmap.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/rmap.c b/mm/rmap.c > index 9c3e773..cb5f70a 100644 > --- a/mm/rmap.c > +++ b/mm/rmap.c > @@ -1564,10 +1564,10 @@ void __put_anon_vma(struct anon_vma *anon_vma) > { > struct anon_vma *root = anon_vma->root; > > + anon_vma_free(anon_vma); > + > if (root != anon_vma && atomic_dec_and_test(&root->refcount)) > anon_vma_free(root); > - > - anon_vma_free(anon_vma); > } > > static struct anon_vma *rmap_walk_anon_lock(struct page *page, > -- > 1.8.5.5 > ^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] mm: rmap: fix use-after-free in __put_anon_vma 2014-06-06 15:09 ` [PATCH v2] mm: rmap: fix use-after-free in __put_anon_vma Andrey Ryabinin 2014-06-06 15:30 ` Peter Zijlstra @ 2014-06-07 21:50 ` David Rientjes 1 sibling, 0 replies; 3+ messages in thread From: David Rientjes @ 2014-06-07 21:50 UTC (permalink / raw) To: Andrey Ryabinin Cc: Andrew Morton, Linus Torvalds, Peter Zijlstra, linux-mm, linux-kernel, koct9i, stable On Fri, 6 Jun 2014, Andrey Ryabinin wrote: > 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 patch puts freeing of child anon_vma before freeing of anon_vma->root. > > Cc: <stable@vger.kernel.org> # v3.0+ > Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com> Acked-by: David Rientjes <rientjes@google.com> ^ permalink raw reply [flat|nested] 3+ messages in thread
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2014-06-06 15:09 ` [PATCH v2] mm: rmap: fix use-after-free in __put_anon_vma Andrey Ryabinin
2014-06-06 15:30 ` Peter Zijlstra
2014-06-07 21:50 ` David Rientjes
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