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Message-ID: <20121211134514.GE18940@secunet.com>
Date: Tue, 11 Dec 2012 14:45:14 +0100
From: Steffen Klassert <steffen.klassert@...unet.com>
To: Duan Jiong <djduanjiong@...il.com>
Cc: davem@...emloft.net, netdev@...r.kernel.org
Subject: Re: [PATCH] ipv6: fix the bug when propagating Redirect Message
On Tue, Dec 11, 2012 at 08:58:20PM +0800, Duan Jiong wrote:
>
> Just like you said, i try to use ndisc_parse_options() to instead
> of the loop, but i find the skb->data can't be changed in function
> ndisc_parse_options() due to lack of arguments. So i think it is
> better to continue to use the loop. How do you think this?
>
You can change the data pointer after ndisc_parse_options().
Something like the (untested) patch below should do it.
include/net/ndisc.h | 7 +++++++
net/ipv6/ndisc.c | 20 ++++++++++++++++++++
2 files changed, 27 insertions(+)
diff --git a/include/net/ndisc.h b/include/net/ndisc.h
index 980d263..c17bccd 100644
--- a/include/net/ndisc.h
+++ b/include/net/ndisc.h
@@ -78,6 +78,13 @@ struct ra_msg {
__be32 retrans_timer;
};
+struct rd_msg {
+ struct icmp6hdr icmph;
+ struct in6_addr target;
+ struct in6_addr dest;
+ __u8 opt[0];
+};
+
struct nd_opt_hdr {
__u8 nd_opt_type;
__u8 nd_opt_len;
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index 2edce30..9afd23f 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -1333,6 +1333,12 @@ out:
static void ndisc_redirect_rcv(struct sk_buff *skb)
{
+ u8 *hdr;
+ struct ndisc_options ndopts;
+ struct rd_msg *msg = (struct rd_msg *) skb_transport_header(skb);
+ u32 ndoptlen = skb->tail - (skb->transport_header +
+ offsetof(struct rd_msg, opt));
+
#ifdef CONFIG_IPV6_NDISC_NODETYPE
switch (skb->ndisc_nodetype) {
case NDISC_NODETYPE_HOST:
@@ -1349,6 +1355,20 @@ static void ndisc_redirect_rcv(struct sk_buff *skb)
return;
}
+ if (!ndisc_parse_options(msg->opt, ndoptlen, &ndopts)) {
+ ND_PRINTK(2, warn, "Redirect: invalid ND options\n");
+ return;
+ }
+
+ if (!ndopts.nd_opts_rh)
+ return;
+
+ hdr = (u8 *) ndopts.nd_opts_rh;
+ hdr += 8;
+
+ if (!pskb_pull(skb, hdr - skb_transport_header(skb)))
+ return;
+
icmpv6_notify(skb, NDISC_REDIRECT, 0, 0);
}
--
1.7.9.5
--
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