netdev - Re: [PATCH] [UDPv6] Possible dst leak in udpv6

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Message-Id: <20080604.012619.30196060.yoshfuji@linux-ipv6.org>
Date:	Wed, 04 Jun 2008 01:26:19 +0900 (JST)
From:	YOSHIFUJI Hideaki / 吉藤英明 
	<yoshfuji@...ux-ipv6.org>
To:	den@...nvz.org
Cc:	davem@...emloft.net, netdev@...r.kernel.org, kaber@...sh.net,
	yoshfuji@...ux-ipv6.org
Subject: Re: [PATCH] [UDPv6] Possible dst leak in udpv6_sendmsg.

In article <1212493845.6499.29.camel@...s.sw.ru> (at Tue, 03 Jun 2008 15:50:45 +0400), "Denis V. Lunev" <den@...nvz.org> says:

> On Tue, 2008-06-03 at 20:35 +0900, YOSHIFUJI Hideaki / 吉藤英明 wrote:
> > In article <1212491322-9161-1-git-send-email-den@...nvz.org> (at Tue,  3 Jun 2008 15:08:42 +0400), "Denis V. Lunev" <den@...nvz.org> says:
> > 
> > > ip6_sk_dst_lookup returns held dst entry. It should be released on all paths
> > > beyond this point. Add missed release when up->pending is set.
> > 
> > Which kernel are you refering?
> The patch is made against current net-2.6 tree, though all kernels are
> affected, starting at least RHEL5
> 
> > And, would you please take a look at ipv4 side as well?
> 
> ipv4 is ok, the code looks the same but there is an ip_rt_put at the
> out: label.
> 

Okay, I think we have one more leakage here (in do_confirm path).
How about this?

diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 1fd784f..47123bf 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -848,12 +848,14 @@ do_append_data:
 		} else {
 			dst_release(dst);
 		}
+		dst = NULL;
 	}
 
 	if (err > 0)
 		err = np->recverr ? net_xmit_errno(err) : 0;
 	release_sock(sk);
 out:
+	dst_release(dst);
 	fl6_sock_release(flowlabel);
 	if (!err)
 		return len;

--yoshfuji
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