The experience with openurl/OPEN_URL has shown that just sending
a URL to a client is not enough and we often need different
behaviour of the client depending on circumstances. Replace
OPEN_URL with a more flexible WEB_AUTH pending auth method.
Patch v2: use WEB_AUTH instead WEBAUTH
Signed-off-by: Arne Schwabe <a...@rfc2549.org>
---
doc/management-notes.txt | 41 ++++++++++++++++++++++++++-----------
include/openvpn-plugin.h.in | 2 +-
2 files changed, 30 insertions(+), 13 deletions(-)
diff --git a/doc/management-notes.txt b/doc/management-notes.txt
index c20344298..d794a4a98 100644
--- a/doc/management-notes.txt
+++ b/doc/management-notes.txt
@@ -645,11 +645,11 @@ Before issuing a client-pending-auth to a client instead
of a
client-auth/client-deny, the server should check the IV_SSO
environment variable for whether the method is supported. Currently
defined methods are crtext for challenge/response using text
-(e.g., TOTP), openurl and proxy_url for opening a URL in the client to
-continue authentication. A client supporting the first two methods would
-set
+(e.g., TOTP), openurl (deprecated) and webauth for opening a URL in
+the client to continue authentication. A client supporting webauth and
+crtext would set
- setenv IV_SSO openurl,crtext
+ setenv IV_SSO webauth,crtext
The variable name IV_SSO is historic as AUTH_PENDING was first used
to signal single sign on support. To keep compatibility with existing
@@ -668,33 +668,50 @@ notification as
where {EXTRA} is formatted as received from the server.
Currently defined formats for {EXTRA} are detailed below.
-openurl
-========
+webauth and openurl
+===================
For a web based extra authentication (like for
SSO/SAML) {EXTRA} should be
OPEN_URL:url
-and client should ask the user to open the URL to continue.
+or
+
+ WEB_AUTH:flags:url
+
+The OPEN_URL method is deprecated as it does not allow to send flags which
+proved to be needed to signal certain behaviour to the client.
+
+The client should ask the user to open the URL to continue.
The space in a control message is limited, so this url should be kept
short to avoid issues. If a longer url is required a URL that redirects
-to the longer URL should be sent instead.
+to the longer URL should be sent instead. The total length is limited to 1024
+bytes which includes the INFO_PRE:WEB_AUTH:flags.
+
+flags is a list of flags which are separated by commas. Currently defined
+flags are:
+
+- proxy (see next pargraph)
+- hidden start the webview in hidden mode (see openvpn3 webauth
documentation)
+- external Do not use an internal webview but use an external browser. Some
+ authentication providers refuse to work in an internal webview.
+
A complete documentation how URLs should be handled on the client is available
in the openvpn3 repository:
https://github.com/OpenVPN/openvpn3/blob/master/doc/webauth.md
-proxy_url
-========
-This is a variant of openurl that allows opening a url via an
+webauth with proxy
+==================
+This is a variant of webauth that allows opening a url via an
HTTP proxy. It could be used to avoid issues with OpenVPN connection's
persist-tun that may cause the web server to be unreachable.
The client should announce proxy_url in its IV_SSO and parse the
PROXY_URL message. The format of {EXTRA} in this case is
-
PROXY_URL:<proxy>:<proxy_port>:<proxyuser_base64>:<proxy_password_base64>:url
+
WEB_AUTH:proxy=<proxy>;<proxy_port>;<proxyuser_base64>;<proxy_password_base64>,flags:url
The proxy should be a literal IPv4 address or IPv6 address enclosed in [] to
avoid
ambiguity in parsing. A literal IP address is preferred as DNS might not be
diff --git a/include/openvpn-plugin.h.in b/include/openvpn-plugin.h.in
index abbfd9c2a..28b845af1 100644
--- a/include/openvpn-plugin.h.in
+++ b/include/openvpn-plugin.h.in
@@ -573,7 +573,7 @@ OPENVPN_PLUGIN_DEF openvpn_plugin_handle_t
OPENVPN_PLUGIN_FUNC(openvpn_plugin_op
* auth_pending_file is
* line 1: timeout in seconds
* line 2: Pending auth method the client needs to support (e.g. openurl)
- * line 3: EXTRA (e.g. OPEN_URL:http://www.example.com)
+ * line 3: EXTRA (e.g. WEBAUTH::http://www.example.com)
*
* In addition the OPENVPN_PLUGIN_CLIENT_CONNECT_DEFER and
* OPENVPN_PLUGIN_CLIENT_CONNECT_DEFER_V2 are called when OpenVPN tries to
--
2.32.0
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