Jens Taprogge wrote:
> Hello.
>
> After upgrading from 2.6.13 an IP Masquerading router panics as soon as
> soon as packages are forwarder (or rather should be). As long as IP
> Masquerading is disabled (and thus no forwarding occurs) the box runs
> stable.
I just sent these two fixes for this and a related problem to Dave.
[NETFILTER]: Fix xfrm lookup after SNAT
To find out if a packet needs to be handled by IPsec after SNAT, packets
are currently rerouted in POST_ROUTING and a new xfrm lookup is done. This
breaks SNAT of non-unicast packets to non-local addresses because the
packet is routed as incoming packet and no neighbour entry is bound to the
dst_entry. In general, it seems to be a bad idea to replace the dst_entry
after the packet was already sent to the output routine because its state
might not match what's expected.
This patch changes the xfrm lookup in POST_ROUTING to re-use the original
dst_entry without routing the packet again. This means no policy routing
can be used for transport mode transforms (which keep the original route)
when packets are SNATed to match the policy, but it looks like the best
we can do for now.
Signed-off-by: Patrick McHardy <[email protected]>
Signed-off-by: Herbert Xu <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
---
commit ee68cea2c26b7a8222f9020f54d22c6067011e8b
tree e99b13be0392532d17a133fe6b9e7edb0a7a4de9
parent 10ee39fe3ff618d274e1cd0f6abbc2917b736bfd
author Patrick McHardy <[email protected]> Wed, 15 Feb 2006 01:34:23 -0800
committer David S. Miller <[email protected]> Wed, 15 Feb 2006 01:34:23 -0800
include/linux/netfilter_ipv4.h | 2 +-
net/ipv4/netfilter.c | 41 ++++++++++++++++++++++++++++++++
net/ipv4/netfilter/ip_nat_standalone.c | 6 ++---
3 files changed, 45 insertions(+), 4 deletions(-)
diff --git a/include/linux/netfilter_ipv4.h b/include/linux/netfilter_ipv4.h
index fdc4a95..43c09d7 100644
--- a/include/linux/netfilter_ipv4.h
+++ b/include/linux/netfilter_ipv4.h
@@ -79,7 +79,7 @@ enum nf_ip_hook_priorities {
#ifdef __KERNEL__
extern int ip_route_me_harder(struct sk_buff **pskb);
-
+extern int ip_xfrm_me_harder(struct sk_buff **pskb);
#endif /*__KERNEL__*/
#endif /*__LINUX_IP_NETFILTER_H*/
diff --git a/net/ipv4/netfilter.c b/net/ipv4/netfilter.c
index 52a3d7c..ed42cdc 100644
--- a/net/ipv4/netfilter.c
+++ b/net/ipv4/netfilter.c
@@ -78,6 +78,47 @@ int ip_route_me_harder(struct sk_buff **
}
EXPORT_SYMBOL(ip_route_me_harder);
+#ifdef CONFIG_XFRM
+int ip_xfrm_me_harder(struct sk_buff **pskb)
+{
+ struct flowi fl;
+ unsigned int hh_len;
+ struct dst_entry *dst;
+
+ if (IPCB(*pskb)->flags & IPSKB_XFRM_TRANSFORMED)
+ return 0;
+ if (xfrm_decode_session(*pskb, &fl, AF_INET) < 0)
+ return -1;
+
+ dst = (*pskb)->dst;
+ if (dst->xfrm)
+ dst = ((struct xfrm_dst *)dst)->route;
+ dst_hold(dst);
+
+ if (xfrm_lookup(&dst, &fl, (*pskb)->sk, 0) < 0)
+ return -1;
+
+ dst_release((*pskb)->dst);
+ (*pskb)->dst = dst;
+
+ /* Change in oif may mean change in hh_len. */
+ hh_len = (*pskb)->dst->dev->hard_header_len;
+ if (skb_headroom(*pskb) < hh_len) {
+ struct sk_buff *nskb;
+
+ nskb = skb_realloc_headroom(*pskb, hh_len);
+ if (!nskb)
+ return -1;
+ if ((*pskb)->sk)
+ skb_set_owner_w(nskb, (*pskb)->sk);
+ kfree_skb(*pskb);
+ *pskb = nskb;
+ }
+ return 0;
+}
+EXPORT_SYMBOL(ip_xfrm_me_harder);
+#endif
+
void (*ip_nat_decode_session)(struct sk_buff *, struct flowi *);
EXPORT_SYMBOL(ip_nat_decode_session);
diff --git a/net/ipv4/netfilter/ip_nat_standalone.c b/net/ipv4/netfilter/ip_nat_standalone.c
index 92c5499..7c3f7d3 100644
--- a/net/ipv4/netfilter/ip_nat_standalone.c
+++ b/net/ipv4/netfilter/ip_nat_standalone.c
@@ -235,19 +235,19 @@ ip_nat_out(unsigned int hooknum,
return NF_ACCEPT;
ret = ip_nat_fn(hooknum, pskb, in, out, okfn);
+#ifdef CONFIG_XFRM
if (ret != NF_DROP && ret != NF_STOLEN
&& (ct = ip_conntrack_get(*pskb, &ctinfo)) != NULL) {
enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
if (ct->tuplehash[dir].tuple.src.ip !=
ct->tuplehash[!dir].tuple.dst.ip
-#ifdef CONFIG_XFRM
|| ct->tuplehash[dir].tuple.src.u.all !=
ct->tuplehash[!dir].tuple.dst.u.all
-#endif
)
- return ip_route_me_harder(pskb) == 0 ? ret : NF_DROP;
+ return ip_xfrm_me_harder(pskb) == 0 ? ret : NF_DROP;
}
+#endif
return ret;
}
[XFRM]: Fix SNAT-related crash in xfrm4_output_finish
When a packet matching an IPsec policy is SNATed so it doesn't match any
policy anymore it looses its xfrm bundle, which makes xfrm4_output_finish
crash because of a NULL pointer dereference.
This patch directs these packets to the regular output path instead. To
avoid replicating the device/protocol assignments and statistics from
ip_output and ip_mc_output, the packet just starts at the begining of
the output path again and skips the next invocation of the POST_ROUTING
hook.
Signed-off-by: Patrick McHardy <[email protected]>
---
commit a31ab06c99e45232b742803677e88363cda2fb85
tree 020e91264409d418d615599a5880df68ca640432
parent ede836cd3164896d741dff1a8d7c1dc0b9b1fdf6
author Patrick McHardy <[email protected]> Wed, 15 Feb 2006 17:30:44 +0100
committer Patrick McHardy <[email protected]> Wed, 15 Feb 2006 17:30:44 +0100
include/linux/netfilter.h | 19 +++++++++++++++----
include/net/ip.h | 1 +
include/net/xfrm.h | 1 -
net/ipv4/ip_gre.c | 3 ++-
net/ipv4/ip_output.c | 16 ++++++++++------
net/ipv4/ipip.c | 3 ++-
net/ipv4/xfrm4_output.c | 13 ++++++++++---
7 files changed, 40 insertions(+), 16 deletions(-)
diff --git a/include/linux/netfilter.h b/include/linux/netfilter.h
index 4cf6088..5deacda 100644
--- a/include/linux/netfilter.h
+++ b/include/linux/netfilter.h
@@ -184,8 +184,11 @@ static inline int nf_hook_thresh(int pf,
struct sk_buff **pskb,
struct net_device *indev,
struct net_device *outdev,
- int (*okfn)(struct sk_buff *), int thresh)
+ int (*okfn)(struct sk_buff *), int thresh,
+ int cond)
{
+ if (!cond)
+ return 1;
#ifndef CONFIG_NETFILTER_DEBUG
if (list_empty(&nf_hooks[pf][hook]))
return 1;
@@ -197,7 +200,7 @@ static inline int nf_hook(int pf, unsign
struct net_device *indev, struct net_device *outdev,
int (*okfn)(struct sk_buff *))
{
- return nf_hook_thresh(pf, hook, pskb, indev, outdev, okfn, INT_MIN);
+ return nf_hook_thresh(pf, hook, pskb, indev, outdev, okfn, INT_MIN, 1);
}
/* Activate hook; either okfn or kfree_skb called, unless a hook
@@ -224,7 +227,13 @@ static inline int nf_hook(int pf, unsign
#define NF_HOOK_THRESH(pf, hook, skb, indev, outdev, okfn, thresh) \
({int __ret; \
-if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, thresh)) == 1)\
+if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, thresh, 1)) == 1)\
+ __ret = (okfn)(skb); \
+__ret;})
+
+#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) \
+({int __ret; \
+if ((__ret=nf_hook_thresh(pf, hook, &(skb), indev, outdev, okfn, INT_MIN, cond)) == 1)\
__ret = (okfn)(skb); \
__ret;})
@@ -295,11 +304,13 @@ extern struct proc_dir_entry *proc_net_n
#else /* !CONFIG_NETFILTER */
#define NF_HOOK(pf, hook, skb, indev, outdev, okfn) (okfn)(skb)
+#define NF_HOOK_COND(pf, hook, skb, indev, outdev, okfn, cond) (okfn)(skb)
static inline int nf_hook_thresh(int pf, unsigned int hook,
struct sk_buff **pskb,
struct net_device *indev,
struct net_device *outdev,
- int (*okfn)(struct sk_buff *), int thresh)
+ int (*okfn)(struct sk_buff *), int thresh,
+ int cont)
{
return okfn(*pskb);
}
diff --git a/include/net/ip.h b/include/net/ip.h
index 8de0697..fab3d5b 100644
--- a/include/net/ip.h
+++ b/include/net/ip.h
@@ -41,6 +41,7 @@ struct inet_skb_parm
#define IPSKB_XFRM_TUNNEL_SIZE 2
#define IPSKB_XFRM_TRANSFORMED 4
#define IPSKB_FRAG_COMPLETE 8
+#define IPSKB_REROUTED 16
};
struct ipcm_cookie
diff --git a/include/net/xfrm.h b/include/net/xfrm.h
index d09ca0e..d6111a2 100644
--- a/include/net/xfrm.h
+++ b/include/net/xfrm.h
@@ -866,7 +866,6 @@ extern int xfrm_state_mtu(struct xfrm_st
extern int xfrm_init_state(struct xfrm_state *x);
extern int xfrm4_rcv(struct sk_buff *skb);
extern int xfrm4_output(struct sk_buff *skb);
-extern int xfrm4_output_finish(struct sk_buff *skb);
extern int xfrm4_tunnel_register(struct xfrm_tunnel *handler);
extern int xfrm4_tunnel_deregister(struct xfrm_tunnel *handler);
extern int xfrm6_rcv_spi(struct sk_buff **pskb, u32 spi);
diff --git a/net/ipv4/ip_gre.c b/net/ipv4/ip_gre.c
index abe2392..9981dcd 100644
--- a/net/ipv4/ip_gre.c
+++ b/net/ipv4/ip_gre.c
@@ -830,7 +830,8 @@ static int ipgre_tunnel_xmit(struct sk_b
skb->h.raw = skb->nh.raw;
skb->nh.raw = skb_push(skb, gre_hlen);
memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
- IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE|IPSKB_XFRM_TRANSFORMED);
+ IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
+ IPSKB_REROUTED);
dst_release(skb->dst);
skb->dst = &rt->u.dst;
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 3324fbf..57d290d 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -207,8 +207,10 @@ static inline int ip_finish_output(struc
{
#if defined(CONFIG_NETFILTER) && defined(CONFIG_XFRM)
/* Policy lookup after SNAT yielded a new policy */
- if (skb->dst->xfrm != NULL)
- return xfrm4_output_finish(skb);
+ if (skb->dst->xfrm != NULL) {
+ IPCB(skb)->flags |= IPSKB_REROUTED;
+ return dst_output(skb);
+ }
#endif
if (skb->len > dst_mtu(skb->dst) &&
!(skb_shinfo(skb)->ufo_size || skb_shinfo(skb)->tso_size))
@@ -271,8 +273,9 @@ int ip_mc_output(struct sk_buff *skb)
newskb->dev, ip_dev_loopback_xmit);
}
- return NF_HOOK(PF_INET, NF_IP_POST_ROUTING, skb, NULL, skb->dev,
- ip_finish_output);
+ return NF_HOOK_COND(PF_INET, NF_IP_POST_ROUTING, skb, NULL, skb->dev,
+ ip_finish_output,
+ !(IPCB(skb)->flags & IPSKB_REROUTED));
}
int ip_output(struct sk_buff *skb)
@@ -284,8 +287,9 @@ int ip_output(struct sk_buff *skb)
skb->dev = dev;
skb->protocol = htons(ETH_P_IP);
- return NF_HOOK(PF_INET, NF_IP_POST_ROUTING, skb, NULL, dev,
- ip_finish_output);
+ return NF_HOOK_COND(PF_INET, NF_IP_POST_ROUTING, skb, NULL, dev,
+ ip_finish_output,
+ !(IPCB(skb)->flags & IPSKB_REROUTED));
}
int ip_queue_xmit(struct sk_buff *skb, int ipfragok)
diff --git a/net/ipv4/ipip.c b/net/ipv4/ipip.c
index e5cbe72..03d1374 100644
--- a/net/ipv4/ipip.c
+++ b/net/ipv4/ipip.c
@@ -622,7 +622,8 @@ static int ipip_tunnel_xmit(struct sk_bu
skb->h.raw = skb->nh.raw;
skb->nh.raw = skb_push(skb, sizeof(struct iphdr));
memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
- IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE|IPSKB_XFRM_TRANSFORMED);
+ IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED |
+ IPSKB_REROUTED);
dst_release(skb->dst);
skb->dst = &rt->u.dst;
diff --git a/net/ipv4/xfrm4_output.c b/net/ipv4/xfrm4_output.c
index d4df0dd..32ad229 100644
--- a/net/ipv4/xfrm4_output.c
+++ b/net/ipv4/xfrm4_output.c
@@ -152,10 +152,16 @@ error_nolock:
goto out_exit;
}
-int xfrm4_output_finish(struct sk_buff *skb)
+static int xfrm4_output_finish(struct sk_buff *skb)
{
int err;
+#ifdef CONFIG_NETFILTER
+ if (!skb->dst->xfrm) {
+ IPCB(skb)->flags |= IPSKB_REROUTED;
+ return dst_output(skb);
+ }
+#endif
while (likely((err = xfrm4_output_one(skb)) == 0)) {
nf_reset(skb);
@@ -178,6 +184,7 @@ int xfrm4_output_finish(struct sk_buff *
int xfrm4_output(struct sk_buff *skb)
{
- return NF_HOOK(PF_INET, NF_IP_POST_ROUTING, skb, NULL, skb->dst->dev,
- xfrm4_output_finish);
+ return NF_HOOK_COND(PF_INET, NF_IP_POST_ROUTING, skb, NULL, skb->dst->dev,
+ xfrm4_output_finish,
+ !(IPCB(skb)->flags & IPSKB_REROUTED));
}
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