clients: use nm_utils_ifname_valid() to validate interface name in nm_vpn_wireguard_import()

We use the filename of the imported .conf file for "connection.interface-name".
That follows what `wg-quick` does.

However, we also validate that the interface name is valid UTF-8
(otherwise -- as it currently is -- the setting couldn't be send via
D-Bus). As such, we have stricter requirements.

We want to fail early and tell the user when the filename is unsuitable.
Failing later gives a worse user experience, because the failure message
about invalid "connection.interface-name" wouldn't make it clear that
the filename is wrong.

Use the appropriate function to validate "connection.interface-name".

Before:

    $ touch $'./a\344b.conf'
    $ nmcli connection import type wireguard file $'./a\344b.conf'
    Error: failed to import './a?b.conf': Failed to create WireGuard connection: connection.interface-name: 'a?b': interface name must be UTF-8 encoded.

Now:

    $ nmcli connection import type wireguard file $'./a\344b.conf'
    Error: failed to import './a?b.conf': The name of the WireGuard config must be a valid interface name followed by ".conf".

1 files changed, 2 insertions, 2 deletions

diff --git a/clients/common/nm-vpn-helpers.c b/clients/common/nm-vpn-helpers.c
index e1d8355147..33490c57d5 100644
--- a/clients/common/nm-vpn-helpers.c
+++ b/clients/common/nm-vpn-helpers.c
@@ -368,13 +368,13 @@ nm_vpn_wireguard_import (const char *filename,
 			memcpy (ifname, cstr, len);
 			ifname[len] = '\0';
 
-			if (nm_utils_ifname_valid_kernel (ifname, NULL))
+			if (nm_utils_ifname_valid (ifname, NMU_IFACE_KERNEL, NULL))
 				ifname_valid = TRUE;
 		}
 	}
 	if (!ifname_valid) {
 		nm_utils_error_set_literal (error, NM_UTILS_ERROR_UNKNOWN,
-		                            _("The WireGuard config file must be a valid interface name followed by \".conf\""));
+		                            _("The name of the WireGuard config must be a valid interface name followed by \".conf\""));
 		return FALSE;
 	}