From: Patrick McHardy <kaber@trash.net>
To: mukesh agrawal <mukesh@cs.cmu.edu>
Cc: coreteam@netfilter.org, netfilter-devel@lists.netfilter.org,
trivial@rustcorp.com.au, linux-kernel@vger.kernel.org
Subject: Re: [netfilter-core] [PATCH 2.6.10 1/1] netfilter: fix crash on nat+icmp packets
Date: Wed, 02 Mar 2005 10:26:41 +0100 [thread overview]
Message-ID: <422586D1.5000609@trash.net> (raw)
In-Reply-To: <Pine.LNX.4.61.0503011830590.31296@slash.mukesh.agrawals.org>
mukesh agrawal wrote:
> The cause of the crash is that udp_manip_pkt reads *pskb into iph before
> calling skb_ip_make_writable, and fails to update iph after the call.
> Since skb_ip_make_writable may delete the original skb when it makes a
> copy, a page fault may occur when udp_manip_pkt later dereferences iph.
This bug has already been fixed in 2.6.11-rc.
Regards
Patrick
>
> diff -uprN linux-2.6.10.orig/net/ipv4/netfilter/ip_nat_proto_udp.c
> linux-2.6.10.fixed/net/ipv4/netfilter/ip_nat_proto_udp.c
> --- linux-2.6.10.orig/net/ipv4/netfilter/ip_nat_proto_udp.c
> 2004-12-24 16:34:01.000000000 -0500
> +++ linux-2.6.10.fixed/net/ipv4/netfilter/ip_nat_proto_udp.c
> 2005-03-01 19:32:21.000000000 -0500
> @@ -95,6 +95,9 @@ udp_manip_pkt(struct sk_buff **pskb,
>
> if (!skb_ip_make_writable(pskb, hdroff + sizeof(hdr)))
> return 0;
> + /* skb_ip_make_writable may have copied the skb, and deleted
> + the original */
> + iph = (struct iphdr *)((*pskb)->data + iphdroff);
>
> hdr = (void *)(*pskb)->data + hdroff;
> if (maniptype == IP_NAT_MANIP_SRC) {
>
prev parent reply other threads:[~2005-03-02 9:28 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-03-02 1:41 [PATCH 2.6.10 1/1] netfilter: fix crash on nat+icmp packets mukesh agrawal
2005-03-02 9:26 ` Patrick McHardy [this message]
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