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* [PATCH] nft: nft_set_attr_get_u32 null pointer deref
@ 2013-10-25 16:55 Phil Oester
  2013-10-27 20:34 ` Pablo Neira Ayuso
  0 siblings, 1 reply; 3+ messages in thread
From: Phil Oester @ 2013-10-25 16:55 UTC (permalink / raw)
  To: netfilter-devel; +Cc: pablo

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As reported by John Sager, nft_set_attr_get_u32 can cause a segfault because
nft_set_attr_get can return NULL.  Check for a non-NULL pointer before
dereferencing.

This closes netfilter bugzilla #868.

Signed-off-by: Phil Oester <kernel@linuxace.com>


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diff --git a/src/set.c b/src/set.c
index 74ec1e3..85f73cf 100644
--- a/src/set.c
+++ b/src/set.c
@@ -183,8 +183,8 @@ EXPORT_SYMBOL(nft_set_attr_get_str);
 
 uint32_t nft_set_attr_get_u32(struct nft_set *s, uint16_t attr)
 {
-	uint32_t val = *((uint32_t *)nft_set_attr_get(s, attr));
-	return val;
+	const void *val = nft_set_attr_get(s, attr);
+	return val ? *(uint32_t *)val : 0;
 }
 EXPORT_SYMBOL(nft_set_attr_get_u32);
 

^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [PATCH] nft: nft_set_attr_get_u32 null pointer deref
  2013-10-25 16:55 [PATCH] nft: nft_set_attr_get_u32 null pointer deref Phil Oester
@ 2013-10-27 20:34 ` Pablo Neira Ayuso
  2013-10-27 23:29   ` Phil Oester
  0 siblings, 1 reply; 3+ messages in thread
From: Pablo Neira Ayuso @ 2013-10-27 20:34 UTC (permalink / raw)
  To: Phil Oester; +Cc: netfilter-devel

On Fri, Oct 25, 2013 at 09:55:31AM -0700, Phil Oester wrote:
> As reported by John Sager, nft_set_attr_get_u32 can cause a segfault because
> nft_set_attr_get can return NULL.  Check for a non-NULL pointer before
> dereferencing.
> 
> This closes netfilter bugzilla #868.

I have mangled this patch to include possible null dereferences in get
operations with rule objects (similar case). Let me know if you see
any issue with my change.

Applied, thanks.

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [PATCH] nft: nft_set_attr_get_u32 null pointer deref
  2013-10-27 20:34 ` Pablo Neira Ayuso
@ 2013-10-27 23:29   ` Phil Oester
  0 siblings, 0 replies; 3+ messages in thread
From: Phil Oester @ 2013-10-27 23:29 UTC (permalink / raw)
  To: Pablo Neira Ayuso; +Cc: netfilter-devel

On Sun, Oct 27, 2013 at 09:34:26PM +0100, Pablo Neira Ayuso wrote:
> I have mangled this patch to include possible null dereferences in get
> operations with rule objects (similar case). Let me know if you see
> any issue with my change.

Looks good, thanks.

Phil

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2013-10-27 23:29 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2013-10-25 16:55 [PATCH] nft: nft_set_attr_get_u32 null pointer deref Phil Oester
2013-10-27 20:34 ` Pablo Neira Ayuso
2013-10-27 23:29   ` Phil Oester

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