[NetworkManager-openvpn] service: automatically add the "cipher" to the "data-ciphers"

[Thomas Haller <thaller src gnome org>]

commit 020ab0c4b872fa5415ed1a5e682acb3343c7b9f3
Author: Thomas Haller <thaller redhat com>
Date:   Mon Oct 3 21:29:22 2022 +0200

    service: automatically add the "cipher" to the "data-ciphers"
    
    https://gitlab.gnome.org/GNOME/NetworkManager-openvpn/-/merge_requests/46#note_1494723
    
    Fixes: 963b71a83ee1 ('Add support for OpenVPN's --data-ciphers')

 src/nm-openvpn-service.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)
---
diff --git a/src/nm-openvpn-service.c b/src/nm-openvpn-service.c
index 7fac66b..18600d6 100644
--- a/src/nm-openvpn-service.c
+++ b/src/nm-openvpn-service.c
@@ -1676,6 +1676,22 @@ nm_openvpn_start_openvpn_binary (NMOpenvpnPlugin *plugin,
 
        args_add_vpn_data (args, s_vpn, NM_OPENVPN_KEY_DATA_CIPHERS, "--data-ciphers");
 
+       if (nm_setting_vpn_get_data_item (s_vpn, NM_OPENVPN_KEY_CIPHER) &&
+           !nm_setting_vpn_get_data_item (s_vpn, NM_OPENVPN_KEY_DATA_CIPHERS) &&
+           openvpn_binary_detect_version_cached (openvpn_binary, &openvpn_binary_version) >=
+               nmovpn_version_encode (2, 5, 0)) {
+               /* Since 2.5, openvpn will warn if "cipher" is set but "data-ciphers" doesn't
+                * contain the cipher. It still used to automatically add the cipher.
+                * Since 2.6, the cipher is no longer automatically added, which is unlikely
+                * what the user wants.
+                *
+                * We automatically add it, so if the user only sets cipher (e.g. when
+                * having an old profile or targeting 2.4) it still works. So ciphers
+                * means something slightly different for the plugin, unless you set
+                * data-ciphers to anything. */
+               args_add_vpn_data (args, s_vpn, NM_OPENVPN_KEY_CIPHER, "--data-ciphers");
+       }
+
        args_add_vpn_data (args, s_vpn, NM_OPENVPN_KEY_TLS_CIPHER, "--tls-cipher");
 
        tmp = nm_setting_vpn_get_data_item (s_vpn, NM_OPENVPN_KEY_KEYSIZE);