From patchwork Sat Nov 9 15:13:05 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [Openvpn-devel,v2,4/5] Implement sending SSO challenge to clients X-Patchwork-Submitter: Arne Schwabe X-Patchwork-Id: 894 Message-Id: <20191109151306.18597-4-arne@rfc2549.org> To: openvpn-devel@lists.sourceforge.net Date: Sat, 9 Nov 2019 16:13:05 +0100 From: Arne Schwabe List-Id: This implements sending AUTH_PENDING and INFO_PRE messages to clients that indicate that the clients should be continue authentication with a second factor. This can currently be out of band (openurl) or a normal challenge/response 2FA like TOTP (CR_TEXT). Signed-off-by: Arne Schwabe --- doc/management-notes.txt | 26 +++++++++++++++++++++++ src/openvpn/manage.c | 46 ++++++++++++++++++++++++++++++++++++++++ src/openvpn/manage.h | 3 +++ src/openvpn/multi.c | 19 +++++++++++++++++ src/openvpn/push.c | 24 +++++++++++++++++++++ src/openvpn/push.h | 2 ++ 6 files changed, 120 insertions(+) diff --git a/doc/management-notes.txt b/doc/management-notes.txt index e380ca2b..4b405a9b 100644 --- a/doc/management-notes.txt +++ b/doc/management-notes.txt @@ -592,6 +592,32 @@ interface to approve client connections. CID,KID -- client ID and Key ID. See documentation for ">CLIENT:" notification for more info. +COMMAND -- client-sso-auth (OpenVPN 2.5 or higher) +---------------------------------------------------- + +Instruct OpenVPN server to send AUTH_PENDING and INFO_PRE signal +a single sign on url to the client. + + client-sso-auth {CID} {EXTRA} + +The server will send AUTH_PENDING and INFO_PRE,{EXTRA} to the client. +The client is expected to inform the user that authentication is pending and +display the extra information. For the SSO/SAML EXTRA would be OPEN_URL:url +and client should ask to the user to open the URL to continue. + +For the OpenVPN server this is stateless operation and needs to be +followed by a client-deny/client-auth[-nt] command (that is the result of the +out of band authentication). + +Before issuing a client-sso-auth to a client instead of a +client-auth/client-deny, the server should check the IV_SSO +environment variable if the method is support. The currently +defined method are crtext for challenge/response using text +(e.g. TOTP) and openurl for opening an URL in the client to +continue authentication. A client support both methods would set + + setenv IV_SSO openurl,crtext + COMMAND -- client-deny (OpenVPN 2.1 or higher) ----------------------------------------------- diff --git a/src/openvpn/manage.c b/src/openvpn/manage.c index 8dada6f2..c055f2ce 100644 --- a/src/openvpn/manage.c +++ b/src/openvpn/manage.c @@ -105,6 +105,8 @@ man_help(void) msg(M_CLIENT, "client-auth-nt CID KID : Authenticate client-id/key-id CID/KID"); msg(M_CLIENT, "client-deny CID KID R [CR] : Deny auth client-id/key-id CID/KID with log reason"); msg(M_CLIENT, " text R and optional client reason text CR"); + msg(M_CLIENT, "client-sso-auth CID MSG : Instruct OpenVPN to send AUTH_PENDING and INFO_PRE msg" + " to the client and wait for a final client-auth/client-deny"); msg(M_CLIENT, "client-kill CID [M] : Kill client instance CID with message M (def=RESTART)"); msg(M_CLIENT, "env-filter [level] : Set env-var filter level"); #ifdef MANAGEMENT_PF @@ -1001,6 +1003,43 @@ parse_kid(const char *str, unsigned int *kid) } } +/** + * Will send a notification to the client that succesful authentication + * will require an additional step (web based SSO/2-factor auth/etc) + * + * @param man The management interface struct + * @param cid_str The CID in string form + * @param extra The string to be send to the client containing + * the information of the additional steps + */ +static void +man_client_sso_auth(struct management *man, const char *cid_str, const char *extra) +{ + unsigned long cid = 0; + if (parse_cid(cid_str, &cid)) + { + if (man->persist.callback.client_sso) + { + bool ret = (*man->persist.callback.client_sso) + (man->persist.callback.arg, cid, extra); + + if (ret) + { + msg(M_CLIENT, "SUCCESS: client-sso-auth command succeeded"); + } + else + { + msg(M_CLIENT, "SUCCESS: client-sso-auth command failed." + " Extra paramter might be too long"); + } + } + else + { + msg(M_CLIENT, "ERROR: The client-sso-auth command is not supported by the current daemon mode"); + } + } +} + static void man_client_auth(struct management *man, const char *cid_str, const char *kid_str, const bool extra) { @@ -1541,6 +1580,13 @@ man_dispatch_command(struct management *man, struct status_output *so, const cha man_client_auth(man, p[1], p[2], true); } } + else if (streq(p[0], "client-sso-auth")) + { + if (man_need(man, p, 2, 0)) + { + man_client_sso_auth(man, p[1], p[2]); + } + } #ifdef MANAGEMENT_PF else if (streq(p[0], "client-pf")) { diff --git a/src/openvpn/manage.h b/src/openvpn/manage.h index 8acc18bf..f570afc6 100644 --- a/src/openvpn/manage.h +++ b/src/openvpn/manage.h @@ -174,6 +174,9 @@ struct management_callback const char *reason, const char *client_reason, struct buffer_list *cc_config); /* ownership transferred */ + bool (*client_sso) (void *arg, + const unsigned long cid, + const char *url); char *(*get_peer_info) (void *arg, const unsigned long cid); #endif #ifdef MANAGEMENT_PF diff --git a/src/openvpn/multi.c b/src/openvpn/multi.c index d594dd25..692fb62a 100644 --- a/src/openvpn/multi.c +++ b/src/openvpn/multi.c @@ -3288,6 +3288,24 @@ management_kill_by_cid(void *arg, const unsigned long cid, const char *kill_msg) } } +static bool +management_client_sso(void *arg, + const unsigned long cid, + const char *extra) +{ + struct multi_context *m = (struct multi_context *) arg; + struct multi_instance *mi = lookup_by_cid(m, cid); + if (mi) + { + /* sends INFO_PRE and AUTH_PENDING messages to client */ + bool ret = send_sso_messages(&mi->context, extra); + multi_schedule_context_wakeup(m, mi); + return ret; + } + return false; +} + + static bool management_client_auth(void *arg, const unsigned long cid, @@ -3395,6 +3413,7 @@ init_management_callback_multi(struct multi_context *m) #ifdef MANAGEMENT_DEF_AUTH cb.kill_by_cid = management_kill_by_cid; cb.client_auth = management_client_auth; + cb.client_sso = management_client_sso; cb.get_peer_info = management_get_peer_info; #endif #ifdef MANAGEMENT_PF diff --git a/src/openvpn/push.c b/src/openvpn/push.c index ee1cb980..4b375ae3 100644 --- a/src/openvpn/push.c +++ b/src/openvpn/push.c @@ -268,6 +268,30 @@ send_auth_failed(struct context *c, const char *client_reason) gc_free(&gc); } +bool +send_sso_messages(struct context *c, const char* extra) +{ + send_control_channel_string(c, "AUTH_PENDING", D_PUSH); + + static const char info_pre[] = "INFO_PRE,"; + + + size_t len = strlen(extra)+1 + sizeof(info_pre); + if (len > PUSH_BUNDLE_SIZE) + { + return false; + } + struct gc_arena gc = gc_new(); + + struct buffer buf = alloc_buf_gc(len, &gc); + buf_printf(&buf, info_pre); + buf_printf(&buf, "%s", extra); + send_control_channel_string(c, BSTR(&buf), D_PUSH); + + gc_free(&gc); + return true; +} + /* * Send restart message from server to client. */ diff --git a/src/openvpn/push.h b/src/openvpn/push.h index 9cf8fb34..f814f572 100644 --- a/src/openvpn/push.h +++ b/src/openvpn/push.h @@ -70,6 +70,8 @@ void remove_iroutes_from_push_route_list(struct options *o); void send_auth_failed(struct context *c, const char *client_reason); +bool send_sso_messages(struct context *c, const char *url); + void send_restart(struct context *c, const char *kill_msg); /**