From 0845e2d0da03b2d739c87219ad212e604bf57431 Mon Sep 17 00:00:00 2001 From: Steffen Klassert Date: Tue, 16 Sep 2014 10:08:40 +0200 Subject: [PATCH] xfrm: Generate blackhole routes only from route lookup functions [ Upstream commit f92ee61982d6da15a9e49664ecd6405a15a2ee56 ] Currently we genarate a blackhole route route whenever we have matching policies but can not resolve the states. Here we assume that dst_output() is called to kill the balckholed packets. Unfortunately this assumption is not true in all cases, so it is possible that these packets leave the system unwanted. We fix this by generating blackhole routes only from the route lookup functions, here we can guarantee a call to dst_output() afterwards. Fixes: 2774c131b1d ("xfrm: Handle blackhole route creation via afinfo.") Reported-by: Konstantinos Kolelis Signed-off-by: Steffen Klassert Signed-off-by: Greg Kroah-Hartman --- include/net/dst.h | 15 ++++++++++++++- net/ipv4/route.c | 6 +++--- net/ipv6/ip6_output.c | 4 ++-- net/xfrm/xfrm_policy.c | 18 +++++++++++++++++- 4 files changed, 36 insertions(+), 7 deletions(-) diff --git a/include/net/dst.h b/include/net/dst.h index 77eb53f..2a90573 100644 --- a/include/net/dst.h +++ b/include/net/dst.h @@ -476,7 +476,16 @@ static inline struct dst_entry *xfrm_lookup(struct net *net, int flags) { return dst_orig; -} +} + +static inline struct dst_entry *xfrm_lookup_route(struct net *net, + struct dst_entry *dst_orig, + const struct flowi *fl, + struct sock *sk, + int flags) +{ + return dst_orig; +} static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst) { @@ -488,6 +497,10 @@ struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig, const struct flowi *fl, struct sock *sk, int flags); +struct dst_entry *xfrm_lookup_route(struct net *net, struct dst_entry *dst_orig, + const struct flowi *fl, struct sock *sk, + int flags); + /* skb attached with this dst needs transformation if dst->xfrm is valid */ static inline struct xfrm_state *dst_xfrm(const struct dst_entry *dst) { diff --git a/net/ipv4/route.c b/net/ipv4/route.c index ca5a01e..487bb62 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -2268,9 +2268,9 @@ struct rtable *ip_route_output_flow(struct net *net, struct flowi4 *flp4, return rt; if (flp4->flowi4_proto) - rt = (struct rtable *) xfrm_lookup(net, &rt->dst, - flowi4_to_flowi(flp4), - sk, 0); + rt = (struct rtable *)xfrm_lookup_route(net, &rt->dst, + flowi4_to_flowi(flp4), + sk, 0); return rt; } diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 073e5a6..12f7ef0 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1008,7 +1008,7 @@ struct dst_entry *ip6_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6, if (final_dst) fl6->daddr = *final_dst; - return xfrm_lookup(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0); + return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0); } EXPORT_SYMBOL_GPL(ip6_dst_lookup_flow); @@ -1040,7 +1040,7 @@ struct dst_entry *ip6_sk_dst_lookup_flow(struct sock *sk, struct flowi6 *fl6, if (final_dst) fl6->daddr = *final_dst; - return xfrm_lookup(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0); + return xfrm_lookup_route(sock_net(sk), dst, flowi6_to_flowi(fl6), sk, 0); } EXPORT_SYMBOL_GPL(ip6_sk_dst_lookup_flow); diff --git a/net/xfrm/xfrm_policy.c b/net/xfrm/xfrm_policy.c index 1d5c7bf..9d4fa4c 100644 --- a/net/xfrm/xfrm_policy.c +++ b/net/xfrm/xfrm_policy.c @@ -2155,7 +2155,7 @@ struct dst_entry *xfrm_lookup(struct net *net, struct dst_entry *dst_orig, xfrm_pols_put(pols, drop_pols); XFRM_INC_STATS(net, LINUX_MIB_XFRMOUTNOSTATES); - return make_blackhole(net, family, dst_orig); + return ERR_PTR(-EREMOTE); } err = -EAGAIN; @@ -2212,6 +2212,22 @@ dropdst: } EXPORT_SYMBOL(xfrm_lookup); +/* Callers of xfrm_lookup_route() must ensure a call to dst_output(). + * Otherwise we may send out blackholed packets. + */ +struct dst_entry *xfrm_lookup_route(struct net *net, struct dst_entry *dst_orig, + const struct flowi *fl, + struct sock *sk, int flags) +{ + struct dst_entry *dst = xfrm_lookup(net, dst_orig, fl, sk, flags); + + if (IS_ERR(dst) && PTR_ERR(dst) == -EREMOTE) + return make_blackhole(net, dst_orig->ops->family, dst_orig); + + return dst; +} +EXPORT_SYMBOL(xfrm_lookup_route); + static inline int xfrm_secpath_reject(int idx, struct sk_buff *skb, const struct flowi *fl) { -- 2.7.4