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[NETFILTER]: Fix xfrm lookup in ip_route_me_harder/ip6_route_me_harder
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ip_route_me_harder doesn't use the port numbers of the xfrm lookup and
uses ip_route_input for non-local addresses which doesn't do a xfrm
lookup, ip6_route_me_harder doesn't do a xfrm lookup at all.

Use xfrm_decode_session and do the lookup manually, make sure both
only do the lookup if the packet hasn't been transformed already.

Makeing sure the lookup only happens once needs a new field in the
IP6CB, which exceeds the size of skb->cb. The size of skb->cb is
increased to 48b. Apparently the IPv6 mobile extensions need some
more room anyway.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Patrick McHardy authored and David S. Miller committed Jan 7, 2006
1 parent 8cdfab8 commit 3e3850e
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Showing 11 changed files with 34 additions and 12 deletions.
3 changes: 3 additions & 0 deletions include/linux/ipv6.h
Original file line number Diff line number Diff line change
Expand Up @@ -192,6 +192,9 @@ struct inet6_skb_parm {
__u16 dst1;
__u16 lastopt;
__u32 nhoff;
__u16 flags;

#define IP6SKB_XFRM_TRANSFORMED 1
};

#define IP6CB(skb) ((struct inet6_skb_parm*)((skb)->cb))
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2 changes: 1 addition & 1 deletion include/linux/skbuff.h
Original file line number Diff line number Diff line change
Expand Up @@ -251,7 +251,7 @@ struct sk_buff {
* want to keep them across layers you have to do a skb_clone()
* first. This is owned by whoever has the skb queued ATM.
*/
char cb[40];
char cb[48];

unsigned int len,
data_len,
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3 changes: 2 additions & 1 deletion include/net/ip.h
Original file line number Diff line number Diff line change
Expand Up @@ -39,7 +39,8 @@ struct inet_skb_parm

#define IPSKB_FORWARDED 1
#define IPSKB_XFRM_TUNNEL_SIZE 2
#define IPSKB_FRAG_COMPLETE 4
#define IPSKB_XFRM_TRANSFORMED 4
#define IPSKB_FRAG_COMPLETE 8
};

struct ipcm_cookie
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2 changes: 1 addition & 1 deletion include/net/xfrm.h
Original file line number Diff line number Diff line change
Expand Up @@ -668,7 +668,7 @@ static inline int xfrm6_policy_check(struct sock *sk, int dir, struct sk_buff *s
return xfrm_policy_check(sk, dir, skb, AF_INET6);
}


extern int xfrm_decode_session(struct sk_buff *skb, struct flowi *fl, unsigned short family);
extern int __xfrm_route_forward(struct sk_buff *skb, unsigned short family);

static inline int xfrm_route_forward(struct sk_buff *skb, unsigned short family)
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2 changes: 1 addition & 1 deletion net/ipv4/ip_gre.c
Original file line number Diff line number Diff line change
Expand Up @@ -832,7 +832,7 @@ static int ipgre_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
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;
IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE|IPSKB_XFRM_TRANSFORMED);
dst_release(skb->dst);
skb->dst = &rt->u.dst;

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2 changes: 1 addition & 1 deletion net/ipv4/ipip.c
Original file line number Diff line number Diff line change
Expand Up @@ -621,7 +621,7 @@ static int ipip_tunnel_xmit(struct sk_buff *skb, struct net_device *dev)
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;
IPCB(skb)->flags &= ~(IPSKB_XFRM_TUNNEL_SIZE|IPSKB_XFRM_TRANSFORMED);
dst_release(skb->dst);
skb->dst = &rt->u.dst;

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12 changes: 10 additions & 2 deletions net/ipv4/netfilter.c
Original file line number Diff line number Diff line change
Expand Up @@ -7,11 +7,13 @@
#include <linux/netfilter.h>
#include <linux/netfilter_ipv4.h>

#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <linux/icmp.h>
#include <net/route.h>
#include <linux/ip.h>
#include <net/xfrm.h>
#include <net/ip.h>

/* route_me_harder function, used by iptable_nat, iptable_mangle + ip_queue */
int ip_route_me_harder(struct sk_buff **pskb)
Expand All @@ -33,7 +35,6 @@ int ip_route_me_harder(struct sk_buff **pskb)
#ifdef CONFIG_IP_ROUTE_FWMARK
fl.nl_u.ip4_u.fwmark = (*pskb)->nfmark;
#endif
fl.proto = iph->protocol;
if (ip_route_output_key(&rt, &fl) != 0)
return -1;

Expand All @@ -60,6 +61,13 @@ int ip_route_me_harder(struct sk_buff **pskb)
if ((*pskb)->dst->error)
return -1;

#ifdef CONFIG_XFRM
if (!(IPCB(*pskb)->flags & IPSKB_XFRM_TRANSFORMED) &&
xfrm_decode_session(*pskb, &fl, AF_INET) == 0)
if (xfrm_lookup(&(*pskb)->dst, &fl, (*pskb)->sk, 0))
return -1;
#endif

/* Change in oif may mean change in hh_len. */
hh_len = (*pskb)->dst->dev->hard_header_len;
if (skb_headroom(*pskb) < hh_len) {
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1 change: 1 addition & 0 deletions net/ipv4/xfrm4_output.c
Original file line number Diff line number Diff line change
Expand Up @@ -140,6 +140,7 @@ static int xfrm4_output_one(struct sk_buff *skb)
x = dst->xfrm;
} while (x && !x->props.mode);

IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
err = 0;

out_exit:
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9 changes: 8 additions & 1 deletion net/ipv6/netfilter.c
Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,7 @@
#include <net/dst.h>
#include <net/ipv6.h>
#include <net/ip6_route.h>
#include <net/xfrm.h>

int ip6_route_me_harder(struct sk_buff *skb)
{
Expand All @@ -21,11 +22,17 @@ int ip6_route_me_harder(struct sk_buff *skb)
{ .ip6_u =
{ .daddr = iph->daddr,
.saddr = iph->saddr, } },
.proto = iph->nexthdr,
};

dst = ip6_route_output(skb->sk, &fl);

#ifdef CONFIG_XFRM
if (!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) &&
xfrm_decode_session(skb, &fl, AF_INET6) == 0)
if (xfrm_lookup(&skb->dst, &fl, skb->sk, 0))
return -1;
#endif

if (dst->error) {
IP6_INC_STATS(IPSTATS_MIB_OUTNOROUTES);
LIMIT_NETDEBUG(KERN_DEBUG "ip6_route_me_harder: No more route.\n");
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1 change: 1 addition & 0 deletions net/ipv6/xfrm6_output.c
Original file line number Diff line number Diff line change
Expand Up @@ -139,6 +139,7 @@ static int xfrm6_output_one(struct sk_buff *skb)
x = dst->xfrm;
} while (x && !x->props.mode);

IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
err = 0;

out_exit:
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9 changes: 5 additions & 4 deletions net/xfrm/xfrm_policy.c
Original file line number Diff line number Diff line change
Expand Up @@ -951,8 +951,8 @@ xfrm_policy_ok(struct xfrm_tmpl *tmpl, struct sec_path *sp, int start,
return start;
}

static int
_decode_session(struct sk_buff *skb, struct flowi *fl, unsigned short family)
int
xfrm_decode_session(struct sk_buff *skb, struct flowi *fl, unsigned short family)
{
struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);

Expand All @@ -963,6 +963,7 @@ _decode_session(struct sk_buff *skb, struct flowi *fl, unsigned short family)
xfrm_policy_put_afinfo(afinfo);
return 0;
}
EXPORT_SYMBOL(xfrm_decode_session);

static inline int secpath_has_tunnel(struct sec_path *sp, int k)
{
Expand All @@ -982,7 +983,7 @@ int __xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb,
u8 fl_dir = policy_to_flow_dir(dir);
u32 sk_sid;

if (_decode_session(skb, &fl, family) < 0)
if (xfrm_decode_session(skb, &fl, family) < 0)
return 0;

sk_sid = security_sk_sid(sk, &fl, fl_dir);
Expand Down Expand Up @@ -1055,7 +1056,7 @@ int __xfrm_route_forward(struct sk_buff *skb, unsigned short family)
{
struct flowi fl;

if (_decode_session(skb, &fl, family) < 0)
if (xfrm_decode_session(skb, &fl, family) < 0)
return 0;

return xfrm_lookup(&skb->dst, &fl, NULL, 0) == 0;
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