[IPSEC]: Added xfrm_decode_session_reverse and xfrmX_policy_check_reverse
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>
diff --git a/net/ipv4/xfrm4_policy.c b/net/ipv4/xfrm4_policy.c
index 10b72d1..5ccae3a 100644
--- a/net/ipv4/xfrm4_policy.c
+++ b/net/ipv4/xfrm4_policy.c
@@ -115,7 +115,7 @@
}
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);
u8 *xprth = skb_network_header(skb) + iph->ihl * 4;
@@ -131,8 +131,8 @@
if (pskb_may_pull(skb, xprth + 4 - skb->data)) {
__be16 *ports = (__be16 *)xprth;
- fl->fl_ip_sport = ports[0];
- fl->fl_ip_dport = ports[1];
+ fl->fl_ip_sport = ports[!!reverse];
+ fl->fl_ip_dport = ports[!reverse];
}
break;
@@ -174,8 +174,8 @@
}
}
fl->proto = iph->protocol;
- fl->fl4_dst = iph->daddr;
- fl->fl4_src = iph->saddr;
+ fl->fl4_dst = reverse ? iph->saddr : iph->daddr;
+ fl->fl4_src = reverse ? iph->daddr : iph->saddr;
fl->fl4_tos = iph->tos;
}
diff --git a/net/ipv6/xfrm6_policy.c b/net/ipv6/xfrm6_policy.c
index 181cf91..d26b7dc 100644
--- a/net/ipv6/xfrm6_policy.c
+++ b/net/ipv6/xfrm6_policy.c
@@ -123,7 +123,7 @@
}
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);
struct ipv6hdr *hdr = ipv6_hdr(skb);
@@ -132,8 +132,8 @@
u8 nexthdr = nh[IP6CB(skb)->nhoff];
memset(fl, 0, sizeof(struct flowi));
- ipv6_addr_copy(&fl->fl6_dst, &hdr->daddr);
- ipv6_addr_copy(&fl->fl6_src, &hdr->saddr);
+ ipv6_addr_copy(&fl->fl6_dst, reverse ? &hdr->saddr : &hdr->daddr);
+ ipv6_addr_copy(&fl->fl6_src, reverse ? &hdr->daddr : &hdr->saddr);
while (pskb_may_pull(skb, nh + offset + 1 - skb->data)) {
nh = skb_network_header(skb);
@@ -156,8 +156,8 @@
if (pskb_may_pull(skb, nh + offset + 4 - skb->data)) {
__be16 *ports = (__be16 *)exthdr;
- fl->fl_ip_sport = ports[0];
- fl->fl_ip_dport = ports[1];
+ fl->fl_ip_sport = ports[!!reverse];
+ fl->fl_ip_dport = ports[!reverse];
}
fl->proto = nexthdr;
return;
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 3d516d5..2e10d46 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -1732,8 +1732,8 @@
return start;
}
-int
-xfrm_decode_session(struct sk_buff *skb, struct flowi *fl, unsigned short family)
+int __xfrm_decode_session(struct sk_buff *skb, struct flowi *fl,
+ unsigned int family, int reverse)
{
struct xfrm_policy_afinfo *afinfo = xfrm_policy_get_afinfo(family);
int err;
@@ -1741,12 +1741,12 @@
if (unlikely(afinfo == NULL))
return -EAFNOSUPPORT;
- afinfo->decode_session(skb, fl);
+ afinfo->decode_session(skb, fl, reverse);
err = security_xfrm_decode_session(skb, &fl->secid);
xfrm_policy_put_afinfo(afinfo);
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)
{
@@ -1768,11 +1768,16 @@
int npols = 0;
int xfrm_nr;
int pi;
+ int reverse;
struct flowi fl;
- u8 fl_dir = policy_to_flow_dir(dir);
+ u8 fl_dir;
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;
nf_nat_decode_session(skb, &fl, family);
