When not using username and password (i.e. auth-user-pass) it can still make
to provide the client with an auth-token, e.g. for allowing a session to
continue after a reconnect without requiring 2FA again.
However, without --auth-user-pass openvpn does not have a username and will
ignore any pushed auth-token command.
This patch adds support for auth-token-user to set the username that should
be used for auth-token
The spec of using auth-token-user base64-encoded-user are the ones that
OpenVPN3 already implements.
Patch V2: Improve style, fix comments and commit message
Signed-off-by: Arne Schwabe <a...@rfc2549.org>
---
doc/man-sections/client-options.rst | 8 +++++++
src/openvpn/misc.c | 37 +++++++++++++++++++++++++----
src/openvpn/misc.h | 21 +++++++++++++---
src/openvpn/options.c | 5 ++++
src/openvpn/ssl.c | 12 +++++++---
src/openvpn/ssl.h | 2 ++
6 files changed, 74 insertions(+), 11 deletions(-)
diff --git a/doc/man-sections/client-options.rst
b/doc/man-sections/client-options.rst
index af21fbcd..c5b7ad96 100644
--- a/doc/man-sections/client-options.rst
+++ b/doc/man-sections/client-options.rst
@@ -50,6 +50,14 @@ configuration.
after a failed auth. Older clients will keep using the token value and
react according to ``--auth-retry``
+--auth-token-user base64username
+ Companion option to ``--auth-token``. This options allows to override
+ the username used by the client when reauthenticating with the
``auth-token``.
+ It also allows to use ``--auth-token`` in setups that normally do not use
+ username and password.
+
+ The username has to be base64 encoded.
+
--auth-user-pass
Authenticate with server using username/password.
diff --git a/src/openvpn/misc.c b/src/openvpn/misc.c
index feaefb3b..6b6f72be 100644
--- a/src/openvpn/misc.c
+++ b/src/openvpn/misc.c
@@ -490,22 +490,49 @@ void
set_auth_token(struct user_pass *up, struct user_pass *tk, const char *token)
{
- if (strlen(token) && (up->defined || tk->defined))
+ if (strlen(token))
{
- /* auth-token has no password, so it needs the username
- * either already set or copied from up */
strncpynt(tk->password, token, USER_PASS_LEN);
- if (up->defined)
+ tk->token_defined = true;
+
+ /*
+ * --auth-token has no username, so it needs the username
+ * either already set or copied from up, or later set by
+ * --auth-token-user
+ *
+ * Do not overwrite the username if already set to avoid
+ * overwriting an auth-token
+ */
+ if (up->defined && !tk->defined)
{
strncpynt(tk->username, up->username, USER_PASS_LEN);
+ tk->defined = true;
}
- tk->defined = true;
}
/* Cleans user/pass for nocache */
purge_user_pass(up, false);
}
+void
+set_auth_token_user(struct user_pass *tk, const char *username)
+{
+ if (strlen(username))
+ {
+ /* Clear the username before decoding to ensure no old material is left
+ * and also allow decoding to not use all space to ensure the last
byte is
+ * always 0 */
+ CLEAR(tk->username);
+ int len = openvpn_base64_decode(username, tk->username, USER_PASS_LEN
- 1);
+ tk->defined = len > 0;
+ if (!tk->defined)
+ {
+ msg(D_PUSH, "Error decoding auth-token-username");
+ }
+ }
+}
+
+
/*
* Process string received by untrusted peer before
* printing to console or log file.
diff --git a/src/openvpn/misc.h b/src/openvpn/misc.h
index 9b018eb5..df52c94b 100644
--- a/src/openvpn/misc.h
+++ b/src/openvpn/misc.h
@@ -56,6 +56,9 @@ const char *hostname_randomize(const char *hostname, struct
gc_arena *gc);
struct user_pass
{
bool defined;
+ /* For auth-token username and token can be set individually, so
+ * we this second bool to track if the token (password) is defined */
+ bool token_defined;
bool nocache;
/* max length of username/password */
@@ -138,19 +141,31 @@ void fail_user_pass(const char *prefix,
void purge_user_pass(struct user_pass *up, const bool force);
/**
- * Sets the auth-token to token if a username is available from either
- * up or already present in tk. The method will also purge up if
+ * Sets the auth-token to token. Ff a username is available from either
+ * up or already present in tk is the auth-token that will be used as default
+ * username for the token. The method will also purge up if
* the auth-nocache option is active.
*
* @param up (non Auth-token) Username/password
* @param tk auth-token userpass to set
- * @param token token to use as password for the
+ * @param token token to use as password for the auth-token
*
* @note all parameters to this function must not be null.
*/
void set_auth_token(struct user_pass *up, struct user_pass *tk,
const char *token);
+/**
+ * Sets the auth-token username by base64 decoding the passed
+ * username
+ *
+ * @param tk auth-token userpass to set
+ * @param username base64 encoded username to set
+ *
+ * @note all parameters to this function must not be null.
+ */
+void set_auth_token_user(struct user_pass *tk, const char *username);
+
/*
* Process string received by untrusted peer before
* printing to console or log file.
diff --git a/src/openvpn/options.c b/src/openvpn/options.c
index 75c394aa..57d0f9ca 100644
--- a/src/openvpn/options.c
+++ b/src/openvpn/options.c
@@ -8228,6 +8228,11 @@ add_option(struct options *options,
}
#endif
}
+ else if (streq(p[0], "auth-token-user") && p[1] && !p[2])
+ {
+ VERIFY_PERMISSION(OPT_P_ECHO);
+ ssl_set_auth_token_user(p[1]);
+ }
else if (streq(p[0], "single-session") && !p[1])
{
VERIFY_PERMISSION(OPT_P_GENERAL);
diff --git a/src/openvpn/ssl.c b/src/openvpn/ssl.c
index 08b95bc3..8ea133aa 100644
--- a/src/openvpn/ssl.c
+++ b/src/openvpn/ssl.c
@@ -445,6 +445,12 @@ ssl_set_auth_token(const char *token)
set_auth_token(&auth_user_pass, &auth_token, token);
}
+void
+ssl_set_auth_token_user(const char *username)
+{
+ set_auth_token_user(&auth_token, username);
+}
+
/*
* Cleans an auth token and checks if it was active
*/
@@ -2271,8 +2277,8 @@ key_method_2_write(struct buffer *buf, struct tls_session
*session)
}
}
- /* write username/password if specified */
- if (auth_user_pass_enabled)
+ /* write username/password if specified or we are using a auth-token */
+ if (auth_user_pass_enabled || (auth_token.token_defined &&
auth_token.defined))
{
#ifdef ENABLE_MANAGEMENT
auth_user_pass_setup(session->opt->auth_user_pass_file,
session->opt->sci);
@@ -2285,7 +2291,7 @@ key_method_2_write(struct buffer *buf, struct tls_session
*session)
* If we have a valid auth-token, send that instead of real
* username/password
*/
- if (auth_token.defined)
+ if (auth_token.token_defined && auth_token.defined)
{
up = &auth_token;
}
diff --git a/src/openvpn/ssl.h b/src/openvpn/ssl.h
index 8c8cbe02..50c81ee7 100644
--- a/src/openvpn/ssl.h
+++ b/src/openvpn/ssl.h
@@ -443,6 +443,8 @@ void ssl_purge_auth(const bool auth_user_pass_only);
void ssl_set_auth_token(const char *token);
+void ssl_set_auth_token_user(const char *username);
+
bool ssl_clean_auth_token(void);
#ifdef ENABLE_MANAGEMENT
--
2.30.1
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