ipv6: fix source address selection with route leak

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: 0d240e7811 ("net: vrf: Implement get_saddr for IPv6")
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Link: https://patch.msgid.link/20240710081521.3809742-3-nicolas.dichtel@6wind.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Nicolas Dichtel 2024-07-10 10:14:28 +02:00 committed by Jakub Kicinski
parent 6807352353
commit 252442f2ae
3 changed files with 17 additions and 8 deletions

View File

@ -127,18 +127,26 @@ 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);
if (!f6i || !f6i->fib6_prefsrc.plen || l3mdev)
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;
}

View File

@ -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();

View File

@ -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;
}