* [PATCH] netfilter: nf_nat: fix crash in nf_nat_csum
@ 2011-05-29 20:42 Julian Anastasov
2011-06-07 13:07 ` Patrick McHardy
0 siblings, 1 reply; 5+ messages in thread
From: Julian Anastasov @ 2011-05-29 20:42 UTC (permalink / raw)
To: Patrick McHardy; +Cc: netfilter-devel
Fix crash in nf_nat_csum when mangling packets
in OUTPUT hook where skb->dev is not defined, it is set
later before POSTROUTING. Problem happens for CHECKSUM_NONE.
We can check device from rt but using CHECKSUM_PARTIAL
should be safe (skb_checksum_help).
Signed-off-by: Julian Anastasov <ja@ssi.bg>
---
diff -urp v2.6.39/linux/net/ipv4/netfilter/nf_nat_helper.c linux/net/ipv4/netfilter/nf_nat_helper.c
--- v2.6.39/linux/net/ipv4/netfilter/nf_nat_helper.c 2011-01-06 00:01:22.000000000 +0200
+++ linux/net/ipv4/netfilter/nf_nat_helper.c 2011-05-29 23:14:40.166245897 +0300
@@ -160,7 +160,7 @@ static void nf_nat_csum(struct sk_buff *
if (skb->ip_summed != CHECKSUM_PARTIAL) {
if (!(rt->rt_flags & RTCF_LOCAL) &&
- skb->dev->features & NETIF_F_V4_CSUM) {
+ (!skb->dev || skb->dev->features & NETIF_F_V4_CSUM)) {
skb->ip_summed = CHECKSUM_PARTIAL;
skb->csum_start = skb_headroom(skb) +
skb_network_offset(skb) +
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] netfilter: nf_nat: fix crash in nf_nat_csum
2011-05-29 20:42 [PATCH] netfilter: nf_nat: fix crash in nf_nat_csum Julian Anastasov
@ 2011-06-07 13:07 ` Patrick McHardy
2011-06-07 20:02 ` Julian Anastasov
0 siblings, 1 reply; 5+ messages in thread
From: Patrick McHardy @ 2011-06-07 13:07 UTC (permalink / raw)
To: Julian Anastasov; +Cc: netfilter-devel
On 29.05.2011 22:42, Julian Anastasov wrote:
>
> Fix crash in nf_nat_csum when mangling packets
> in OUTPUT hook where skb->dev is not defined, it is set
> later before POSTROUTING. Problem happens for CHECKSUM_NONE.
> We can check device from rt but using CHECKSUM_PARTIAL
> should be safe (skb_checksum_help).
We don't call helpers in LOCAL_OUT, how can this happen?
>
> Signed-off-by: Julian Anastasov <ja@ssi.bg>
> ---
>
> diff -urp v2.6.39/linux/net/ipv4/netfilter/nf_nat_helper.c linux/net/ipv4/netfilter/nf_nat_helper.c
> --- v2.6.39/linux/net/ipv4/netfilter/nf_nat_helper.c 2011-01-06 00:01:22.000000000 +0200
> +++ linux/net/ipv4/netfilter/nf_nat_helper.c 2011-05-29 23:14:40.166245897 +0300
> @@ -160,7 +160,7 @@ static void nf_nat_csum(struct sk_buff *
>
> if (skb->ip_summed != CHECKSUM_PARTIAL) {
> if (!(rt->rt_flags & RTCF_LOCAL) &&
> - skb->dev->features & NETIF_F_V4_CSUM) {
> + (!skb->dev || skb->dev->features & NETIF_F_V4_CSUM)) {
> skb->ip_summed = CHECKSUM_PARTIAL;
> skb->csum_start = skb_headroom(skb) +
> skb_network_offset(skb) +
>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] netfilter: nf_nat: fix crash in nf_nat_csum
2011-06-07 13:07 ` Patrick McHardy
@ 2011-06-07 20:02 ` Julian Anastasov
2011-06-07 23:01 ` Patrick McHardy
0 siblings, 1 reply; 5+ messages in thread
From: Julian Anastasov @ 2011-06-07 20:02 UTC (permalink / raw)
To: Patrick McHardy; +Cc: netfilter-devel
Hello,
On Tue, 7 Jun 2011, Patrick McHardy wrote:
> On 29.05.2011 22:42, Julian Anastasov wrote:
> >
> > Fix crash in nf_nat_csum when mangling packets
> > in OUTPUT hook where skb->dev is not defined, it is set
> > later before POSTROUTING. Problem happens for CHECKSUM_NONE.
> > We can check device from rt but using CHECKSUM_PARTIAL
> > should be safe (skb_checksum_help).
>
> We don't call helpers in LOCAL_OUT, how can this happen?
I think, this happened with IPVS only in OUTPUT hook:
tcp_snat_handler -> ip_vs_ftp_out -> nf_nat_mangle_tcp_packet ->
nf_nat_csum. This is again PASV FTP via loopback.
> > diff -urp v2.6.39/linux/net/ipv4/netfilter/nf_nat_helper.c linux/net/ipv4/netfilter/nf_nat_helper.c
> > --- v2.6.39/linux/net/ipv4/netfilter/nf_nat_helper.c 2011-01-06 00:01:22.000000000 +0200
> > +++ linux/net/ipv4/netfilter/nf_nat_helper.c 2011-05-29 23:14:40.166245897 +0300
> > @@ -160,7 +160,7 @@ static void nf_nat_csum(struct sk_buff *
> >
> > if (skb->ip_summed != CHECKSUM_PARTIAL) {
> > if (!(rt->rt_flags & RTCF_LOCAL) &&
> > - skb->dev->features & NETIF_F_V4_CSUM) {
> > + (!skb->dev || skb->dev->features & NETIF_F_V4_CSUM)) {
> > skb->ip_summed = CHECKSUM_PARTIAL;
> > skb->csum_start = skb_headroom(skb) +
> > skb_network_offset(skb) +
> >
Regards
--
Julian Anastasov <ja@ssi.bg>
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] netfilter: nf_nat: fix crash in nf_nat_csum
2011-06-07 20:02 ` Julian Anastasov
@ 2011-06-07 23:01 ` Patrick McHardy
2011-06-08 9:36 ` Patrick McHardy
0 siblings, 1 reply; 5+ messages in thread
From: Patrick McHardy @ 2011-06-07 23:01 UTC (permalink / raw)
To: Julian Anastasov; +Cc: netfilter-devel
On 07.06.2011 22:02, Julian Anastasov wrote:
>
> Hello,
>
> On Tue, 7 Jun 2011, Patrick McHardy wrote:
>
>> On 29.05.2011 22:42, Julian Anastasov wrote:
>>>
>>> Fix crash in nf_nat_csum when mangling packets
>>> in OUTPUT hook where skb->dev is not defined, it is set
>>> later before POSTROUTING. Problem happens for CHECKSUM_NONE.
>>> We can check device from rt but using CHECKSUM_PARTIAL
>>> should be safe (skb_checksum_help).
>>
>> We don't call helpers in LOCAL_OUT, how can this happen?
>
> I think, this happened with IPVS only in OUTPUT hook:
> tcp_snat_handler -> ip_vs_ftp_out -> nf_nat_mangle_tcp_packet ->
> nf_nat_csum. This is again PASV FTP via loopback.
I see, thanks. I'll add a comment and will apply this tommorrow.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] netfilter: nf_nat: fix crash in nf_nat_csum
2011-06-07 23:01 ` Patrick McHardy
@ 2011-06-08 9:36 ` Patrick McHardy
0 siblings, 0 replies; 5+ messages in thread
From: Patrick McHardy @ 2011-06-08 9:36 UTC (permalink / raw)
To: Julian Anastasov; +Cc: netfilter-devel
On 08.06.2011 01:01, Patrick McHardy wrote:
> On 07.06.2011 22:02, Julian Anastasov wrote:
>>
>> Hello,
>>
>> On Tue, 7 Jun 2011, Patrick McHardy wrote:
>>
>>> On 29.05.2011 22:42, Julian Anastasov wrote:
>>>>
>>>> Fix crash in nf_nat_csum when mangling packets
>>>> in OUTPUT hook where skb->dev is not defined, it is set
>>>> later before POSTROUTING. Problem happens for CHECKSUM_NONE.
>>>> We can check device from rt but using CHECKSUM_PARTIAL
>>>> should be safe (skb_checksum_help).
>>>
>>> We don't call helpers in LOCAL_OUT, how can this happen?
>>
>> I think, this happened with IPVS only in OUTPUT hook:
>> tcp_snat_handler -> ip_vs_ftp_out -> nf_nat_mangle_tcp_packet ->
>> nf_nat_csum. This is again PASV FTP via loopback.
>
> I see, thanks. I'll add a comment and will apply this tommorrow.
I must have overlooked the message, just noticed that this patch
is already applied,
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2011-06-08 9:36 UTC | newest]
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2011-05-29 20:42 [PATCH] netfilter: nf_nat: fix crash in nf_nat_csum Julian Anastasov
2011-06-07 13:07 ` Patrick McHardy
2011-06-07 20:02 ` Julian Anastasov
2011-06-07 23:01 ` Patrick McHardy
2011-06-08 9:36 ` Patrick McHardy
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