[NETFILTER]: Fix bridge netfilter related in xfrm_lookup
The bridge-netfilter code attaches a fake dst_entry with dst->ops == NULL
to purely bridged packets. When these packets are SNATed and a policy
lookup is done, xfrm_lookup crashes because it tries to dereference
dst->ops.
Change xfrm_lookup not to dereference dst->ops before checking for the
DST_NOXFRM flag and set this flag in the fake dst_entry.
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c
index 6bb0c7e..e060aad 100644
--- a/net/bridge/br_netfilter.c
+++ b/net/bridge/br_netfilter.c
@@ -90,6 +90,7 @@
.dev = &__fake_net_device,
.path = &__fake_rtable.u.dst,
.metrics = {[RTAX_MTU - 1] = 1500},
+ .flags = DST_NOXFRM,
}
},
.rt_flags = 0,
diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c
index 5e6b05a..8206025 100644
--- a/net/xfrm/xfrm_policy.c
+++ b/net/xfrm/xfrm_policy.c
@@ -782,7 +782,7 @@
int nx = 0;
int err;
u32 genid;
- u16 family = dst_orig->ops->family;
+ u16 family;
u8 dir = policy_to_flow_dir(XFRM_POLICY_OUT);
u32 sk_sid = security_sk_sid(sk, fl, dir);
restart:
@@ -796,13 +796,14 @@
if ((dst_orig->flags & DST_NOXFRM) || !xfrm_policy_list[XFRM_POLICY_OUT])
return 0;
- policy = flow_cache_lookup(fl, sk_sid, family, dir,
- xfrm_policy_lookup);
+ policy = flow_cache_lookup(fl, sk_sid, dst_orig->ops->family,
+ dir, xfrm_policy_lookup);
}
if (!policy)
return 0;
+ family = dst_orig->ops->family;
policy->curlft.use_time = (unsigned long)xtime.tv_sec;
switch (policy->action) {
