By default, an address assigned to the output interface is selected when the source address is not specified. This is problematic when a route, configured in a vrf, uses an interface from another vrf (aka route leak). The original vrf does not own the selected source address.

Let's add a check against the output interface and call the appropriate function to select the source address.

CC: stable@vger.kernel.org Fixes: 0d240e7811c4 ("net: vrf: Implement get_saddr for IPv6") Signed-off-by: Nicolas Dichtel nicolas.dichtel@6wind.com --- include/net/ip6_route.h | 21 ++++++++++++++------- net/ipv6/ip6_output.c | 1 + net/ipv6/route.c | 2 +- 3 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/include/net/ip6_route.h b/include/net/ip6_route.h index a18ed24fed94..667f0a517fd0 100644 --- a/include/net/ip6_route.h +++ b/include/net/ip6_route.h @@ -127,18 +127,25 @@ void rt6_age_exceptions(struct fib6_info *f6i, struct fib6_gc_args *gc_args,

static inline int ip6_route_get_saddr(struct net *net, struct fib6_info *f6i, const struct in6_addr *daddr, - unsigned int prefs, + unsigned int prefs, int l3mdev_index, struct in6_addr *saddr) { + struct net_device *l3mdev; + struct net_device *dev; + bool same_vrf; int err = 0;

- if (f6i && f6i->fib6_prefsrc.plen) { - *saddr = f6i->fib6_prefsrc.addr; - } else { - struct net_device *dev = f6i ? fib6_info_nh_dev(f6i) : NULL; + rcu_read_lock();

- err = ipv6_dev_get_saddr(net, dev, daddr, prefs, saddr); - } + l3mdev = dev_get_by_index_rcu(net, l3mdev_index); + dev = f6i ? fib6_info_nh_dev(f6i) : NULL; + same_vrf = !l3mdev || l3mdev_master_dev_rcu(dev) == l3mdev; + if (f6i && f6i->fib6_prefsrc.plen && same_vrf) + *saddr = f6i->fib6_prefsrc.addr; + else + err = ipv6_dev_get_saddr(net, same_vrf ? dev : l3mdev, daddr, prefs, saddr); + + rcu_read_unlock();

return err; } diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 27d8725445e3..784424ac4147 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1124,6 +1124,7 @@ static int ip6_dst_lookup_tail(struct net *net, const struct sock *sk, from = rt ? rcu_dereference(rt->from) : NULL; err = ip6_route_get_saddr(net, from, &fl6->daddr, sk ? READ_ONCE(inet6_sk(sk)->srcprefs) : 0, + fl6->flowi6_l3mdev, &fl6->saddr); rcu_read_unlock();

diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 8d72ca0b086d..c9a9506b714d 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -5689,7 +5689,7 @@ static int rt6_fill_node(struct net *net, struct sk_buff *skb, goto nla_put_failure; } else if (dest) { struct in6_addr saddr_buf; - if (ip6_route_get_saddr(net, rt, dest, 0, &saddr_buf) == 0 && + if (ip6_route_get_saddr(net, rt, dest, 0, 0, &saddr_buf) == 0 && nla_put_in6_addr(skb, RTA_PREFSRC, &saddr_buf)) goto nla_put_failure; }