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[IPSEC]: Added xfrm_decode_session_reverse and xfrmX_policy_check_reverse

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RFC 4301 requires us to relookup ICMP traffic that does not match any
policies using the reverse of its payload.  This patch adds the functions
xfrm_decode_session_reverse and xfrmX_policy_check_reverse so we can get
the reverse flow to perform such a lookup.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Herbert Xu 2007-12-12 10:44:16 -08:00 committed by David S. Miller
parent 815f4e57e9
commit d5422efe68
5 changed files with 80 additions and 21 deletions
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1
include/linux/xfrm.h
View file

@ -114,6 +114,7 @@ enum
XFRM_POLICY_IN = 0, XFRM_POLICY_IN = 0,
XFRM_POLICY_OUT = 1, XFRM_POLICY_OUT = 1,
XFRM_POLICY_FWD = 2, XFRM_POLICY_FWD = 2,
XFRM_POLICY_MASK = 3,
XFRM_POLICY_MAX = 3 XFRM_POLICY_MAX = 3
}; };

63
include/net/xfrm.h
View file

@ -239,7 +239,8 @@ struct xfrm_policy_afinfo {
int (*get_saddr)(xfrm_address_t *saddr, xfrm_address_t *daddr); int (*get_saddr)(xfrm_address_t *saddr, xfrm_address_t *daddr);
struct dst_entry *(*find_bundle)(struct flowi *fl, struct xfrm_policy *policy); struct dst_entry *(*find_bundle)(struct flowi *fl, struct xfrm_policy *policy);
void (*decode_session)(struct sk_buff *skb, void (*decode_session)(struct sk_buff *skb,
struct flowi *fl); struct flowi *fl,
int reverse);
int (*get_tos)(struct flowi *fl); int (*get_tos)(struct flowi *fl);
int (*fill_dst)(struct xfrm_dst *xdst, int (*fill_dst)(struct xfrm_dst *xdst,
struct net_device *dev); struct net_device *dev);
@ -844,14 +845,23 @@ xfrm_state_addr_cmp(struct xfrm_tmpl *tmpl, struct xfrm_state *x, unsigned short
#ifdef CONFIG_XFRM #ifdef CONFIG_XFRM
extern int __xfrm_policy_check(struct sock *, int dir, struct sk_buff *skb, unsigned short family); extern int __xfrm_policy_check(struct sock *, int dir, struct sk_buff *skb, unsigned short family);
static inline int xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb, unsigned short family) static inline int __xfrm_policy_check2(struct sock *sk, int dir,
struct sk_buff *skb,
unsigned int family, int reverse)
{ {
int ndir = dir | (reverse ? XFRM_POLICY_MASK + 1 : 0);
if (sk && sk->sk_policy[XFRM_POLICY_IN]) if (sk && sk->sk_policy[XFRM_POLICY_IN])
return __xfrm_policy_check(sk, dir, skb, family); return __xfrm_policy_check(sk, ndir, skb, family);
return (!xfrm_policy_count[dir] && !skb->sp) || return (!xfrm_policy_count[dir] && !skb->sp) ||
(skb->dst->flags & DST_NOPOLICY) || (skb->dst->flags & DST_NOPOLICY) ||
__xfrm_policy_check(sk, dir, skb, family); __xfrm_policy_check(sk, ndir, skb, family);
}
static inline int xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb, unsigned short family)
{
return __xfrm_policy_check2(sk, dir, skb, family, 0);
} }
static inline int xfrm4_policy_check(struct sock *sk, int dir, struct sk_buff *skb) static inline int xfrm4_policy_check(struct sock *sk, int dir, struct sk_buff *skb)
@ -864,7 +874,34 @@ static inline int xfrm6_policy_check(struct sock *sk, int dir, struct sk_buff *s
return xfrm_policy_check(sk, dir, skb, AF_INET6); return xfrm_policy_check(sk, dir, skb, AF_INET6);
} }
extern int xfrm_decode_session(struct sk_buff *skb, struct flowi *fl, unsigned short family); static inline int xfrm4_policy_check_reverse(struct sock *sk, int dir,
struct sk_buff *skb)
{
return __xfrm_policy_check2(sk, dir, skb, AF_INET, 1);
}
static inline int xfrm6_policy_check_reverse(struct sock *sk, int dir,
struct sk_buff *skb)
{
return __xfrm_policy_check2(sk, dir, skb, AF_INET6, 1);
}
extern int __xfrm_decode_session(struct sk_buff *skb, struct flowi *fl,
unsigned int family, int reverse);
static inline int xfrm_decode_session(struct sk_buff *skb, struct flowi *fl,
unsigned int family)
{
return __xfrm_decode_session(skb, fl, family, 0);
}
static inline int xfrm_decode_session_reverse(struct sk_buff *skb,
struct flowi *fl,
unsigned int family)
{
return __xfrm_decode_session(skb, fl, family, 1);
}
extern int __xfrm_route_forward(struct sk_buff *skb, 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) static inline int xfrm_route_forward(struct sk_buff *skb, unsigned short family)
@ -925,6 +962,22 @@ static inline int xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *sk
{ {
return 1; return 1;
} }
static inline int xfrm_decode_session_reverse(struct sk_buff *skb,
struct flowi *fl,
unsigned int family)
{
return -ENOSYS;
}
static inline int xfrm4_policy_check_reverse(struct sock *sk, int dir,
struct sk_buff *skb)
{
return 1;
}
static inline int xfrm6_policy_check_reverse(struct sock *sk, int dir,
struct sk_buff *skb)
{
return 1;
}
#endif #endif
static __inline__ static __inline__

10
net/ipv4/xfrm4_policy.c
View file

@ -115,7 +115,7 @@ static int xfrm4_fill_dst(struct xfrm_dst *xdst, struct net_device *dev)
} }
static void static void
_decode_session4(struct sk_buff *skb, struct flowi *fl) _decode_session4(struct sk_buff *skb, struct flowi *fl, int reverse)
{ {
struct iphdr *iph = ip_hdr(skb); struct iphdr *iph = ip_hdr(skb);
u8 *xprth = skb_network_header(skb) + iph->ihl * 4; u8 *xprth = skb_network_header(skb) + iph->ihl * 4;
@ -131,8 +131,8 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl)
if (pskb_may_pull(skb, xprth + 4 - skb->data)) { if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
__be16 *ports = (__be16 *)xprth; __be16 *ports = (__be16 *)xprth;
fl->fl_ip_sport = ports[0]; fl->fl_ip_sport = ports[!!reverse];
fl->fl_ip_dport = ports[1]; fl->fl_ip_dport = ports[!reverse];
} }
break; break;
@ -174,8 +174,8 @@ _decode_session4(struct sk_buff *skb, struct flowi *fl)
} }
} }
fl->proto = iph->protocol; fl->proto = iph->protocol;
fl->fl4_dst = iph->daddr; fl->fl4_dst = reverse ? iph->saddr : iph->daddr;
fl->fl4_src = iph->saddr; fl->fl4_src = reverse ? iph->daddr : iph->saddr;
fl->fl4_tos = iph->tos; fl->fl4_tos = iph->tos;
} }

10
net/ipv6/xfrm6_policy.c
View file

@ -123,7 +123,7 @@ static int xfrm6_fill_dst(struct xfrm_dst *xdst, struct net_device *dev)
} }
static inline void static inline void
_decode_session6(struct sk_buff *skb, struct flowi *fl) _decode_session6(struct sk_buff *skb, struct flowi *fl, int reverse)
{ {
u16 offset = skb_network_header_len(skb); u16 offset = skb_network_header_len(skb);
struct ipv6hdr *hdr = ipv6_hdr(skb); struct ipv6hdr *hdr = ipv6_hdr(skb);
@ -132,8 +132,8 @@ _decode_session6(struct sk_buff *skb, struct flowi *fl)
u8 nexthdr = nh[IP6CB(skb)->nhoff]; u8 nexthdr = nh[IP6CB(skb)->nhoff];
memset(fl, 0, sizeof(struct flowi)); memset(fl, 0, sizeof(struct flowi));
ipv6_addr_copy(&fl->fl6_dst, &hdr->daddr); ipv6_addr_copy(&fl->fl6_dst, reverse ? &hdr->saddr : &hdr->daddr);
ipv6_addr_copy(&fl->fl6_src, &hdr->saddr); ipv6_addr_copy(&fl->fl6_src, reverse ? &hdr->daddr : &hdr->saddr);
while (pskb_may_pull(skb, nh + offset + 1 - skb->data)) { while (pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
nh = skb_network_header(skb); nh = skb_network_header(skb);
@ -156,8 +156,8 @@ _decode_session6(struct sk_buff *skb, struct flowi *fl)
if (pskb_may_pull(skb, nh + offset + 4 - skb->data)) { if (pskb_may_pull(skb, nh + offset + 4 - skb->data)) {
__be16 *ports = (__be16 *)exthdr; __be16 *ports = (__be16 *)exthdr;
fl->fl_ip_sport = ports[0]; fl->fl_ip_sport = ports[!!reverse];
fl->fl_ip_dport = ports[1]; fl->fl_ip_dport = ports[!reverse];
} }
fl->proto = nexthdr; fl->proto = nexthdr;
return; return;

17
net/xfrm/xfrm_policy.c
View file

@ -1732,8 +1732,8 @@ xfrm_policy_ok(struct xfrm_tmpl *tmpl, struct sec_path *sp, int start,
return start; return start;
} }
int int __xfrm_decode_session(struct sk_buff *skb, struct flowi *fl,
xfrm_decode_session(struct sk_buff *skb, struct flowi *fl, unsigned short family) unsigned int family, int reverse)
{ {
struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family); struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
int err; int err;
@ -1741,12 +1741,12 @@ xfrm_decode_session(struct sk_buff *skb, struct flowi *fl, unsigned short family
if (unlikely(afinfo == NULL)) if (unlikely(afinfo == NULL))
return -EAFNOSUPPORT; return -EAFNOSUPPORT;
afinfo->decode_session(skb, fl); afinfo->decode_session(skb, fl, reverse);
err = security_xfrm_decode_session(skb, &fl->secid); err = security_xfrm_decode_session(skb, &fl->secid);
xfrm_policy_put_afinfo(afinfo); xfrm_policy_put_afinfo(afinfo);
return err; return err;
} }
EXPORT_SYMBOL(xfrm_decode_session); EXPORT_SYMBOL(__xfrm_decode_session);
static inline int secpath_has_nontransport(struct sec_path *sp, int k, int *idxp) static inline int secpath_has_nontransport(struct sec_path *sp, int k, int *idxp)
{ {
@ -1768,11 +1768,16 @@ int __xfrm_policy_check(struct sock *sk, int dir, struct sk_buff *skb,
int npols = 0; int npols = 0;
int xfrm_nr; int xfrm_nr;
int pi; int pi;
int reverse;
struct flowi fl; struct flowi fl;
u8 fl_dir = policy_to_flow_dir(dir); u8 fl_dir;
int xerr_idx = -1; int xerr_idx = -1;
if (xfrm_decode_session(skb, &fl, family) < 0) reverse = dir & ~XFRM_POLICY_MASK;
dir &= XFRM_POLICY_MASK;
fl_dir = policy_to_flow_dir(dir);
if (__xfrm_decode_session(skb, &fl, family, reverse) < 0)
return 0; return 0;
nf_nat_decode_session(skb, &fl, family); nf_nat_decode_session(skb, &fl, family);