path: root/net
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authorPaolo Abeni <>2016-01-29 12:30:19 +0100
committerDavid S. Miller <>2016-01-29 20:31:26 -0800
commit6f21c96a78b835259546d8f3fb4edff0f651d478 (patch)
treeff2e2fbf07eb56dc35a57d700d8a8f4df94da171 /net
parent39a4867a9b481afce3f28d2c7e216bdd6ff51417 (diff)
ipv6: enforce flowi6_oif usage in ip6_dst_lookup_tail()
The current implementation of ip6_dst_lookup_tail basically ignore the egress ifindex match: if the saddr is set, ip6_route_output() purposefully ignores flowi6_oif, due to the commit d46a9d678e4c ("net: ipv6: Dont add RT6_LOOKUP_F_IFACE flag if saddr set"), if the saddr is 'any' the first route lookup in ip6_dst_lookup_tail fails, but upon failure a second lookup will be performed with saddr set, thus ignoring the ifindex constraint. This commit adds an output route lookup function variant, which allows the caller to specify lookup flags, and modify ip6_dst_lookup_tail() to enforce the ifindex match on the second lookup via said helper. ip6_route_output() becames now a static inline function build on top of ip6_route_output_flags(); as a side effect, out-of-tree modules need now a GPL license to access the output route lookup functionality. Signed-off-by: Paolo Abeni <> Acked-by: Hannes Frederic Sowa <> Acked-by: David Ahern <> Signed-off-by: David S. Miller <>
Diffstat (limited to 'net')
2 files changed, 8 insertions, 5 deletions
diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index 23de98f976d5..a163102f1803 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -909,6 +909,7 @@ static int ip6_dst_lookup_tail(struct net *net, const struct sock *sk,
struct rt6_info *rt;
int err;
+ int flags = 0;
/* The correct way to handle this would be to do
* ip6_route_get_saddr, and then ip6_route_output; however,
@@ -940,10 +941,13 @@ static int ip6_dst_lookup_tail(struct net *net, const struct sock *sk,
*dst = NULL;
+ if (fl6->flowi6_oif)
+ flags |= RT6_LOOKUP_F_IFACE;
if (!*dst)
- *dst = ip6_route_output(net, sk, fl6);
+ *dst = ip6_route_output_flags(net, sk, fl6, flags);
err = (*dst)->error;
if (err)
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 3c8834bc822d..ed446639219c 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1183,11 +1183,10 @@ static struct rt6_info *ip6_pol_route_output(struct net *net, struct fib6_table
return ip6_pol_route(net, table, fl6->flowi6_oif, fl6, flags);
-struct dst_entry *ip6_route_output(struct net *net, const struct sock *sk,
- struct flowi6 *fl6)
+struct dst_entry *ip6_route_output_flags(struct net *net, const struct sock *sk,
+ struct flowi6 *fl6, int flags)
struct dst_entry *dst;
- int flags = 0;
bool any_src;
dst = l3mdev_rt6_dst_by_oif(net, fl6);
@@ -1208,7 +1207,7 @@ struct dst_entry *ip6_route_output(struct net *net, const struct sock *sk,
return fib6_rule_lookup(net, fl6, flags, ip6_pol_route_output);
struct dst_entry *ip6_blackhole_route(struct net *net, struct dst_entry *dst_orig)