commit 6807352353561187a718e87204458999dbcbba1b upstream.
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.
The flowi4_l3mdev field doesn't exist in the linux-5.15.y branch. The field
flowi4_oif is used instead to get the l3 master device.
CC: stable@xxxxxxxxxxxxxxx
Fixes: 8cbb512c923d ("net: Add source address lookup op for VRF")
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx>
Reviewed-by: David Ahern <dsahern@xxxxxxxxxx>
Link: https://patch.msgid.link/20240710081521.3809742-2-nicolas.dichtel@xxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@xxxxxxxxx>
---
net/ipv4/fib_semantics.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index 735901b8c9f6..188f87ffff69 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -2286,6 +2286,15 @@ void fib_select_path(struct net *net, struct fib_result *res,
fib_select_default(fl4, res);
check_saddr:
- if (!fl4->saddr)
- fl4->saddr = fib_result_prefsrc(net, res);
+ if (!fl4->saddr) {
+ struct net_device *l3mdev;
+
+ l3mdev = l3mdev_master_dev_rcu(dev_get_by_index_rcu(net, fl4->flowi4_oif));
+
+ 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);
+ }
}
--
2.43.1
