From da083c3b9bc1b5720a4dcbef9c32bbbbec0dcce6 Mon Sep 17 00:00:00 2001 From: Arne Schwabe Date: Wed, 1 Mar 2023 14:53:53 +0100 Subject: [PATCH] Make sending plain text control message session aware The control messages coming from auth pending should always be on the session that triggered them (i.e. INITIAL or ACTIVE) and not always on the active session. Rework the code path that trigger those messsages from management and plugin/script to specify the TLS session. We only support the two TLS sessions that are supposed to be active. TLS sessions in any lame slot (TM_LAME or KS_LAME) are not considered to be candidates for sending messages as these slots only serve to keep key material around. Unfortunately, this fix requires the management interface to be changed to allow including the specific session the messages should to go to. As there are very few users of this interface with auth-pending, I made this a hard change instead of adding hacky workaround code that is not always working correctly anyway. send_control_channel_string() will continue to only use the primary session and key but the current users of that (push replys and exit notification) already require the established session to be the active one, so there no changes needed at the moment. Github: fixes OpenVPN/openvpn#256 Signed-off-by: Arne Schwabe Acked-by: Gert Doering Message-Id: <20230301135353.2811069-2-arne@rfc2549.org> URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg26320.html Signed-off-by: Gert Doering (cherry picked from commit a261e173341f8e68505a6ab5a413d09b0797a459) --- Changes.rst | 13 +++++++++++++ doc/management-notes.txt | 13 +++++++++---- src/openvpn/forward.c | 12 ++++++------ src/openvpn/forward.h | 11 ++++++----- src/openvpn/manage.c | 13 ++++++++----- src/openvpn/manage.h | 3 ++- src/openvpn/multi.c | 20 +++++++++++++++++++- src/openvpn/push.c | 27 +++++++++++++++++++-------- src/openvpn/push.h | 8 +++++--- src/openvpn/ssl_verify.c | 9 +++++---- 10 files changed, 92 insertions(+), 37 deletions(-) diff --git a/Changes.rst b/Changes.rst index ba7952b3296..032ef108806 100644 --- a/Changes.rst +++ b/Changes.rst @@ -1,3 +1,16 @@ +Overview of changes in 2.6.2 +============================ + +Bug fixes +--------- +- sending of AUTH_PENDING and INFO_PRE messages fixed (OpenVPN/openvpn#256) + +User visible changes +-------------------- +- The ``client-pending-auth`` management command now requires also the + key id. The management version has been changed to 5 to indicate this change. + + Overview of changes in 2.6.1 ============================ diff --git a/doc/management-notes.txt b/doc/management-notes.txt index 34f301db7e0..b9947fa342a 100644 --- a/doc/management-notes.txt +++ b/doc/management-notes.txt @@ -613,10 +613,10 @@ COMMAND -- client-pending-auth (OpenVPN 2.5 or higher) Instruct OpenVPN server to send AUTH_PENDING and INFO_PRE message to signal a pending authenticating to the client. A pending auth means -that the connecting requires extra authentication like a one time +that connecting requires extra authentication like a one time password or doing a single sign on via web. - client-pending-auth {CID} {EXTRA} {TIMEOUT} + client-pending-auth {CID} {KID} {EXTRA} {TIMEOUT} The server will send AUTH_PENDING and INFO_PRE,{EXTRA} to the client. If the client supports accepting keywords to AUTH_PENDING (announced via IV_PROTO), @@ -639,11 +639,16 @@ Both client and server limit the maximum timeout to the smaller value of half th For the format of {EXTRA} see below. For OpenVPN server this is a 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). +(that is the result of the out-of-band authentication). + +Note that the {KID} argument has been added in management version 5 +to specify the pending client key the authentication belongs to. +This ensures that the pending auth message is tied strictly to the +authentication session. 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 +environment variable for whether the method is supported. Currently, defined methods are crtext for challenge/response using text (e.g., TOTP), openurl (deprecated) and webauth for opening a URL in the client to continue authentication. A client supporting webauth and diff --git a/src/openvpn/forward.c b/src/openvpn/forward.c index 29490a2c4bc..28a96f940d8 100644 --- a/src/openvpn/forward.c +++ b/src/openvpn/forward.c @@ -366,20 +366,20 @@ check_connection_established(struct context *c) } bool -send_control_channel_string_dowork(struct tls_multi *multi, +send_control_channel_string_dowork(struct tls_session *session, const char *str, int msglevel) { struct gc_arena gc = gc_new(); bool stat; - ASSERT(multi); - struct key_state *ks = get_key_scan(multi, 0); + ASSERT(session); + struct key_state *ks = &session->key[KS_PRIMARY]; /* buffered cleartext write onto TLS control channel */ stat = tls_send_payload(ks, (uint8_t *) str, strlen(str) + 1); msg(msglevel, "SENT CONTROL [%s]: '%s' (status=%d)", - tls_common_name(multi, false), + session->common_name ? session->common_name : "UNDEF", sanitize_control_message(str, &gc), (int) stat); @@ -399,8 +399,8 @@ send_control_channel_string(struct context *c, const char *str, int msglevel) { if (c->c2.tls_multi) { - bool ret = send_control_channel_string_dowork(c->c2.tls_multi, - str, msglevel); + struct tls_session *session = &c->c2.tls_multi->session[TM_ACTIVE]; + bool ret = send_control_channel_string_dowork(session, str, msglevel); reschedule_multi_process(c); return ret; diff --git a/src/openvpn/forward.h b/src/openvpn/forward.h index 7376bca23ab..e19115ea178 100644 --- a/src/openvpn/forward.h +++ b/src/openvpn/forward.h @@ -265,21 +265,22 @@ send_control_channel_string(struct context *c, const char *str, int msglevel); /* * Send a string to remote over the TLS control channel. - * Used for push/pull messages, passing username/password, - * etc. + * Used for push/pull messages, auth pending and other clear text + * control messages. * * This variant does not schedule the actual sending of the message * The caller needs to ensure that it is scheduled or call * send_control_channel_string * - * @param multi - The tls_multi structure of the VPN tunnel associated - * with the packet. + * @param session - The session structure of the VPN tunnel associated + * with the packet. The method will always use the + * primary key (KS_PRIMARY) for sending the message * @param str - The message to be sent * @param msglevel - Message level to use for logging */ bool -send_control_channel_string_dowork(struct tls_multi *multi, +send_control_channel_string_dowork(struct tls_session *session, const char *str, int msglevel); diff --git a/src/openvpn/manage.c b/src/openvpn/manage.c index db88e347911..05358af4525 100644 --- a/src/openvpn/manage.c +++ b/src/openvpn/manage.c @@ -1042,22 +1042,25 @@ parse_uint(const char *str, const char *what, unsigned int *uint) * * @param man The management interface struct * @param cid_str The CID in string form + * @param kid_str The key ID in string form * @param extra The string to be send to the client containing * the information of the additional steps */ static void man_client_pending_auth(struct management *man, const char *cid_str, - const char *extra, const char *timeout_str) + const char *kid_str, const char *extra, + const char *timeout_str) { unsigned long cid = 0; + unsigned int kid = 0; unsigned int timeout = 0; - if (parse_cid(cid_str, &cid) + if (parse_cid(cid_str, &cid) && parse_uint(kid_str, "KID", &kid) && parse_uint(timeout_str, "TIMEOUT", &timeout)) { if (man->persist.callback.client_pending_auth) { bool ret = (*man->persist.callback.client_pending_auth) - (man->persist.callback.arg, cid, extra, timeout); + (man->persist.callback.arg, cid, kid, extra, timeout); if (ret) { @@ -1594,9 +1597,9 @@ man_dispatch_command(struct management *man, struct status_output *so, const cha } else if (streq(p[0], "client-pending-auth")) { - if (man_need(man, p, 3, 0)) + if (man_need(man, p, 4, 0)) { - man_client_pending_auth(man, p[1], p[2], p[3]); + man_client_pending_auth(man, p[1], p[2], p[3], p[4]); } } else if (streq(p[0], "rsa-sig")) diff --git a/src/openvpn/manage.h b/src/openvpn/manage.h index 2ced9083581..07317a402ae 100644 --- a/src/openvpn/manage.h +++ b/src/openvpn/manage.h @@ -52,7 +52,7 @@ #include "socket.h" #include "mroute.h" -#define MANAGEMENT_VERSION 4 +#define MANAGEMENT_VERSION 5 #define MANAGEMENT_N_PASSWORD_RETRIES 3 #define MANAGEMENT_LOG_HISTORY_INITIAL_SIZE 100 #define MANAGEMENT_ECHO_BUFFER_SIZE 100 @@ -194,6 +194,7 @@ struct management_callback struct buffer_list *cc_config); /* ownership transferred */ bool (*client_pending_auth) (void *arg, const unsigned long cid, + const unsigned int kid, const char *extra, unsigned int timeout); char *(*get_peer_info) (void *arg, const unsigned long cid); diff --git a/src/openvpn/multi.c b/src/openvpn/multi.c index 53c17b3a462..933bf9bc3d6 100644 --- a/src/openvpn/multi.c +++ b/src/openvpn/multi.c @@ -3989,15 +3989,33 @@ management_kill_by_cid(void *arg, const unsigned long cid, const char *kill_msg) static bool management_client_pending_auth(void *arg, const unsigned long cid, + const unsigned int mda_key_id, const char *extra, unsigned int timeout) { struct multi_context *m = (struct multi_context *) arg; struct multi_instance *mi = lookup_by_cid(m, cid); + if (mi) { + struct tls_multi *multi = mi->context.c2.tls_multi; + struct tls_session *session; + + if (multi->session[TM_INITIAL].key[KS_PRIMARY].mda_key_id == mda_key_id) + { + session = &multi->session[TM_INITIAL]; + } + else if (multi->session[TM_ACTIVE].key[KS_PRIMARY].mda_key_id == mda_key_id) + { + session = &multi->session[TM_ACTIVE]; + } + else + { + return false; + } + /* sends INFO_PRE and AUTH_PENDING messages to client */ - bool ret = send_auth_pending_messages(mi->context.c2.tls_multi, extra, + bool ret = send_auth_pending_messages(multi, session, extra, timeout); reschedule_multi_process(&mi->context); multi_schedule_context_wakeup(m, mi); diff --git a/src/openvpn/push.c b/src/openvpn/push.c index 4453e426178..54e53f6aa48 100644 --- a/src/openvpn/push.c +++ b/src/openvpn/push.c @@ -412,7 +412,16 @@ send_auth_failed(struct context *c, const char *client_reason) { buf_printf(&buf, ",%s", client_reason); } - send_control_channel_string(c, BSTR(&buf), D_PUSH); + + /* We kill the whole session, send the AUTH_FAILED to any TLS session + * that might be active */ + send_control_channel_string_dowork(&c->c2.tls_multi->session[TM_INITIAL], + BSTR(&buf), D_PUSH); + send_control_channel_string_dowork(&c->c2.tls_multi->session[TM_ACTIVE], + BSTR(&buf), D_PUSH); + + reschedule_multi_process(c); + } gc_free(&gc); @@ -420,10 +429,11 @@ send_auth_failed(struct context *c, const char *client_reason) bool -send_auth_pending_messages(struct tls_multi *tls_multi, const char *extra, - unsigned int timeout) +send_auth_pending_messages(struct tls_multi *tls_multi, + struct tls_session *session, + const char *extra, unsigned int timeout) { - struct key_state *ks = get_key_scan(tls_multi, 0); + struct key_state *ks = &session->key[KS_PRIMARY]; static const char info_pre[] = "INFO_PRE,"; @@ -440,7 +450,7 @@ send_auth_pending_messages(struct tls_multi *tls_multi, const char *extra, struct gc_arena gc = gc_new(); if ((proto & IV_PROTO_AUTH_PENDING_KW) == 0) { - send_control_channel_string_dowork(tls_multi, "AUTH_PENDING", D_PUSH); + send_control_channel_string_dowork(session, "AUTH_PENDING", D_PUSH); } else { @@ -451,7 +461,7 @@ send_auth_pending_messages(struct tls_multi *tls_multi, const char *extra, struct buffer buf = alloc_buf_gc(len, &gc); buf_printf(&buf, auth_pre); buf_printf(&buf, "%u", timeout); - send_control_channel_string_dowork(tls_multi, BSTR(&buf), D_PUSH); + send_control_channel_string_dowork(session, BSTR(&buf), D_PUSH); } size_t len = strlen(extra) + 1 + sizeof(info_pre); @@ -464,7 +474,7 @@ send_auth_pending_messages(struct tls_multi *tls_multi, const char *extra, struct buffer buf = alloc_buf_gc(len, &gc); buf_printf(&buf, info_pre); buf_printf(&buf, "%s", extra); - send_control_channel_string_dowork(tls_multi, BSTR(&buf), D_PUSH); + send_control_channel_string_dowork(session, BSTR(&buf), D_PUSH); ks->auth_deferred_expire = now + timeout; @@ -741,6 +751,7 @@ send_push_reply_auth_token(struct tls_multi *multi) { struct gc_arena gc = gc_new(); struct push_list push_list = { 0 }; + struct tls_session *session = &multi->session[TM_ACTIVE]; prepare_auth_token_push_reply(multi, &gc, &push_list); @@ -751,7 +762,7 @@ send_push_reply_auth_token(struct tls_multi *multi) /* Construct a mimimal control channel push reply message */ struct buffer buf = alloc_buf_gc(PUSH_BUNDLE_SIZE, &gc); buf_printf(&buf, "%s,%s", push_reply_cmd, e->option); - send_control_channel_string_dowork(multi, BSTR(&buf), D_PUSH); + send_control_channel_string_dowork(session, BSTR(&buf), D_PUSH); gc_free(&gc); } diff --git a/src/openvpn/push.h b/src/openvpn/push.h index 5e594a30aee..f43ab0966e3 100644 --- a/src/openvpn/push.h +++ b/src/openvpn/push.h @@ -78,16 +78,18 @@ void send_auth_failed(struct context *c, const char *client_reason); * more details on message format */ bool -send_auth_pending_messages(struct tls_multi *tls_multi, const char *extra, +send_auth_pending_messages(struct tls_multi *tls_multi, + struct tls_session *session, const char *extra, unsigned int timeout); void send_restart(struct context *c, const char *kill_msg); /** * Sends a push reply message only containin the auth-token to update - * the auth-token on the client + * the auth-token on the client. Always pushes to the active session * - * @param multi - The tls_multi structure belonging to the instance to push to + * @param multi - The \c tls_multi structure belonging to the instance + * to push to */ void send_push_reply_auth_token(struct tls_multi *multi); diff --git a/src/openvpn/ssl_verify.c b/src/openvpn/ssl_verify.c index 996aee01ffc..1b589f1a6ea 100644 --- a/src/openvpn/ssl_verify.c +++ b/src/openvpn/ssl_verify.c @@ -916,7 +916,8 @@ check_auth_pending_method(const char *peer_info, const char *method) */ static bool key_state_check_auth_pending_file(struct auth_deferred_status *ads, - struct tls_multi *multi) + struct tls_multi *multi, + struct tls_session *session) { bool ret = true; if (ads->auth_pending_file) @@ -965,7 +966,7 @@ key_state_check_auth_pending_file(struct auth_deferred_status *ads, } else { - send_auth_pending_messages(multi, BSTR(extra_buf), timeout); + send_auth_pending_messages(multi, session, BSTR(extra_buf), timeout); } } @@ -1390,7 +1391,7 @@ verify_user_pass_script(struct tls_session *session, struct tls_multi *multi, /* Check if we the plugin has written the pending auth control * file and send the pending auth to the client */ if (!key_state_check_auth_pending_file(&ks->script_auth, - multi)) + multi, session)) { retval = OPENVPN_PLUGIN_FUNC_ERROR; key_state_rm_auth_control_files(&ks->script_auth); @@ -1514,7 +1515,7 @@ verify_user_pass_plugin(struct tls_session *session, struct tls_multi *multi, { /* Check if the plugin has written the pending auth control * file and send the pending auth to the client */ - if (!key_state_check_auth_pending_file(&ks->plugin_auth, multi)) + if (!key_state_check_auth_pending_file(&ks->plugin_auth, multi, session)) { retval = OPENVPN_PLUGIN_FUNC_ERROR; }