[PATCH net-next 4/4] netconsole: reject a target mixing IPv4 and IPv6 addresses

The local_ip and remote_ip configfs attributes are written independently
and nothing stops a user from mixing ipv4 and ipv6. This leads to an
ipv4 address being zero-extended into an ipv6 header or an ipv6 address
being truncated to its first 4 bytes for an ipv4 header.

The command-line parser already refuses such a mismatch. This adds a
similar check when a dynamic target is being enabled.

Signed-off-by: Gustavo Luiz Duarte <[email protected]>
---
 drivers/net/netconsole.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index a41b0a5ce64f..69621705d68d 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -477,6 +477,13 @@ static int netcons_netpoll_setup(struct netconsole_target *nt)
 		goto unlock;
 	}
 
+	if (nt->local_ip.family != AF_UNSPEC &&
+	    nt->local_ip.family != nt->remote_ip.family) {
+		np_err(np, "local and remote IP address families differ, aborting\n");
+		err = -EINVAL;
+		goto unlock;
+	}
+
 	if (np->dev_name[0])
 		ndev = __dev_get_by_name(net, np->dev_name);
 	else if (is_valid_ether_addr(np->dev_mac))

-- 
2.55.0