Re: [PATCH] ip6_tunnel: fix a soft lockup when there is no active tunnel for an encapsulated packet
From: Herbert Xu [EMAIL PROTECTED] Date: Sat, 25 Mar 2006 08:45:39 +1100 Hugo Santos [EMAIL PROTECTED] wrote: This patch fixes a soft lockup in ip6_tunnel when not using xfrm6_tunnel (CONFIG_INET6_TUNNEL). It is triggered when an encapsula- ted packet reaches ip6ip6_rcv() and there is no tunnel associated with it. The error path returns a positive value (1) which will trigger ip6_input to re-submit the packet for processing. As no skb parameters have been changed, ip6ip6_rcv() will continue to be called with the exact same context. Also, ip6ip6_rcv() should free the skb when discarding it. Signed-off-by: Hugo Santos [EMAIL PROTECTED] OK this is a bit ugly but will do for now. Could you please do it for the ICMP packet and IPv4 as well? I don't want to apply this, for now, it's correct but really ugly :) I'd rather the suggested cleanup occur to solve this, and I think the fix is not so urgent that we can wait for the correct version to get coded up. Thanks. - To unsubscribe from this list: send the line unsubscribe netdev in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] ip6_tunnel: fix a soft lockup when there is no active tunnel for an encapsulated packet
I'd rather the suggested cleanup occur to solve this, and I think the fix is not so urgent that we can wait for the correct version to get coded up. I would be glad to code a better version like i specified in an earlier mail. I just didn't do it yet because Herbert said he would do it. And Dave, i'm not sure i agree with it not being urgent. Surely the number of people that have ip6_tunnel loaded is reduced, but any host in the internet is able to hang any such machine by sending an easily crafted packet. If Herbert doesn't have the time, i can code the patch today as this fix is important for me. Hugo signature.asc Description: Digital signature
Re: [PATCH] ip6_tunnel: fix a soft lockup when there is no active tunnel for an encapsulated packet
host in the internet is able to hang any such machine by sending an The ipv6-enabled internet of course :-) Hugo signature.asc Description: Digital signature
Re: [PATCH] ip6_tunnel: fix a soft lockup when there is no active tunnel for an encapsulated packet
When xfrm6_tunnel is in use you've just made it use a freed skb. Also IPv4 has the same problem so we shold fix them both. I didn't hit this since i'm not currently using xfrm6_tunnel (which is also why i got the soft lockup). I'll consider the case when xfrm6_tunnel is being used, and submit another patch. Thanks, Hugo signature.asc Description: Digital signature
Re: [PATCH] ip6_tunnel: fix a soft lockup when there is no active tunnel for an encapsulated packet
Hugo Santos [EMAIL PROTECTED] wrote:
This patch fixes a soft lockup in ip6_tunnel when not using
xfrm6_tunnel (CONFIG_INET6_TUNNEL). It is triggered when an encapsula-
ted packet reaches ip6ip6_rcv() and there is no tunnel associated with
it. The error path returns a positive value (1) which will trigger
ip6_input to re-submit the packet for processing. As no skb parameters
have been changed, ip6ip6_rcv() will continue to be called with the
exact same context. Also, ip6ip6_rcv() should free the skb when
discarding it.
Signed-off-by: Hugo Santos [EMAIL PROTECTED]
OK this is a bit ugly but will do for now. Could you please do it for
the ICMP packet and IPv4 as well?
Thanks,
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Re: [PATCH] ip6_tunnel: fix a soft lockup when there is no active tunnel for an encapsulated packet
OK this is a bit ugly but will do for now. Could you please do it for
the ICMP packet and IPv4 as well?
I find it ugly that the same function, in this case ip6ip6_rcv(), is
used in two contexts where the expected behaviour differs. Also, using
the current #ifdefs, ip6_tunnel is only loadable when xfrm6_tunnel
isn't loaded (as xfrm6_tunnel takes over as IPPROTO_IPV6 handler). A
solution would involve ip6_tunnel depend on xfrm6_tunnel if it was
built either statically or as a module (something that i don't quite
appreciate due to the extra tunnel-spi-lookup but that could do for
now).
Hugo
Thanks,
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Re: [PATCH] ip6_tunnel: fix a soft lockup when there is no active tunnel for an encapsulated packet
From: Hugo Santos [EMAIL PROTECTED] Date: Sat, 25 Mar 2006 00:18:04 + I find it ugly that the same function, in this case ip6ip6_rcv(), is used in two contexts where the expected behaviour differs. It would have been even worse, IMHO, to have two copies of nearly identical code sitting around which is basically what the alternative is. - To unsubscribe from this list: send the line unsubscribe netdev in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] ip6_tunnel: fix a soft lockup when there is no active tunnel for an encapsulated packet
On Fri, Mar 24, 2006 at 04:31:15PM -0800, David S. Miller wrote:
It would have been even worse, IMHO, to have two copies of
nearly identical code sitting around which is basically what
the alternative is.
Actually, it might be cleaner to have wrappers around a common
(possibly inline as well) function. Let me have a go at that.
Cheers,
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Re: [PATCH] ip6_tunnel: fix a soft lockup when there is no active tunnel for an encapsulated packet
From: Herbert Xu [EMAIL PROTECTED] Date: Sat, 25 Mar 2006 11:36:36 +1100 On Fri, Mar 24, 2006 at 04:31:15PM -0800, David S. Miller wrote: It would have been even worse, IMHO, to have two copies of nearly identical code sitting around which is basically what the alternative is. Actually, it might be cleaner to have wrappers around a common (possibly inline as well) function. Let me have a go at that. Sounds good. - To unsubscribe from this list: send the line unsubscribe netdev in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] ip6_tunnel: fix a soft lockup when there is no active tunnel for an encapsulated packet
It would have been even worse, IMHO, to have two copies of
nearly identical code sitting around which is basically what
the alternative is.
We don't need two copies. We just need a function that does the real
work if there is a tunnel to be used (what xfrm6_tunnel needs), and
another one that would call the previous (used when xfrm6_tunnel isn't
used) that frees the skb on errors. Something like:
int ip6ip6_rcv(...) {
...
}
int ip6ip6_proto_rcv(...) {
int res = ip6ip6_rcv();
if (res 0) {
icmpv6_send_error();
kfree_skb();
}
return res;
}
Where ip6ip6_rcv is used when ip6_tunnel is registed via
xfrm6_tunnel, and the second as the IPPROTO_IPV6 handler (when this
functionality is compiled in).
Hugo
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Re: [PATCH] ip6_tunnel: fix a soft lockup when there is no active tunnel for an encapsulated packet
In article [EMAIL PROTECTED] (at Thu, 23 Mar 2006 16:34:12 +), Hugo Santos [EMAIL PROTECTED] says: This patch fixes a soft lockup when encapsulated packets reach ip6ip6_rcv() and there is no tunnel associated with it. The error path returns a positive value (1) which will trigger ip6_input to re-submit the packet for processing. As no skb parameters have been changed, ip6ip6_rcv() will continue to be called on the exact same context. Also, ip6ip6_rcv() should free the skb when discarding it. Signed-off-by: Hugo Santos [EMAIL PROTECTED] Acked-by: YOSHIFUJI Hideaki [EMAIL PROTECTED] -- YOSHIFUJI Hideaki @ USAGI Project [EMAIL PROTECTED] GPG-FP : 9022 65EB 1ECF 3AD1 0BDF 80D8 4807 F894 E062 0EEA - To unsubscribe from this list: send the line unsubscribe netdev in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] ip6_tunnel: fix a soft lockup when there is no active tunnel for an encapsulated packet
Hugo Santos [EMAIL PROTECTED] wrote:
This patch fixes a soft lockup when encapsulated packets reach
ip6ip6_rcv() and there is no tunnel associated with it. The error
path returns a positive value (1) which will trigger ip6_input to
re-submit the packet for processing. As no skb parameters have been
changed, ip6ip6_rcv() will continue to be called on the exact same
context. Also, ip6ip6_rcv() should free the skb when discarding it.
The assessment is correct but I think this fix is wrong.
--- linux-2.6.16/net/ipv6/ip6_tunnel.c.orig 2006-03-23 16:19:19.0
+
+++ linux-2.6.16/net/ipv6/ip6_tunnel.c 2006-03-23 16:32:07.0 +
@@ -557,7 +557,8 @@ ip6ip6_rcv(struct sk_buff **pskb)
read_unlock(ip6ip6_lock);
icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_ADDR_UNREACH, 0,
skb-dev);
discard:
- return 1;
+ kfree_skb(skb);
+ return -1;
}
When xfrm6_tunnel is in use you've just made it use a freed skb. Also
IPv4 has the same problem so we shold fix them both.
Cheers,
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