Commit 68073523 authored by Nicolas Dichtel's avatar Nicolas Dichtel Committed by Jakub Kicinski
Browse files

ipv4: 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: 8cbb512c ("net: Add source address lookup op for VRF")
Signed-off-by: default avatarNicolas Dichtel <nicolas.dichtel@6wind.com>
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20240710081521.3809742-2-nicolas.dichtel@6wind.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent f67a90a0

net/ipv4/fib_semantics.c

+11 −2
Original line number Diff line number Diff line
@@ -2270,6 +2270,15 @@ void fib_select_path(struct net *net, struct fib_result *res, 
		fib_select_default(fl4, res);



check_saddr:

	if (!fl4->saddr)

	if (!fl4->saddr) {

		struct net_device *l3mdev;



		l3mdev = dev_get_by_index_rcu(net, fl4->flowi4_l3mdev);



		if (!l3mdev ||

		    l3mdev_master_dev_rcu(FIB_RES_DEV(*res)) == l3mdev)

			fl4->saddr = fib_result_prefsrc(net, res);

		else

			fl4->saddr = inet_select_addr(l3mdev, 0, RT_SCOPE_LINK);

	}

}