From: Arne Schwabe Date: Thu, 20 May 2021 15:11:42 +0000 (+0200) Subject: Add connection_established as state in tls_multi->context_auth X-Git-Tag: v2.6_beta1~472 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=d01277608a248f31df3fde1883eba6dd8d16a1e4;p=thirdparty%2Fopenvpn.git Add connection_established as state in tls_multi->context_auth The socket_info->connection_establish is set through link_socket_set_outgoing_addr when we reach FULL_SYNC. This patch introduces a new state in context_auth that replaces the connection_established state for TLS connections. This make the state machine easier to understand. Also, rename "enum client_connect_status" to "multi_status", re-order states so CAS_NOT_CONNECTED (=0) is the default state, and introduce CAS_CONNECT_DONE as numerically highest so "are we done?" can be easily checked. This is part of the patchset to fix CVE-2020-15078 in "master" by reorganizing the handling of incoming new and renegotiated TLS sessions to make the code easier to understand and less prone to "edge case" issues. Patch v2: fix p2p mode server without (without ncp) CVE: 2020-15078 Signed-off-by: Arne Schwabe Acked-by: Antonio Quartulli Message-Id: <20210520151148.2565578-3-arne@rfc2549.org> URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg22419.html Signed-off-by: Gert Doering --- diff --git a/src/openvpn/forward.c b/src/openvpn/forward.c index 89017b8cf..e4d0fa7d0 100644 --- a/src/openvpn/forward.c +++ b/src/openvpn/forward.c @@ -280,7 +280,7 @@ static void check_connection_established(struct context *c) { - if (CONNECTION_ESTABLISHED(c)) + if (connection_established(c)) { /* if --pull was specified, send a push request to server */ if (c->c2.tls_multi && c->options.pull) @@ -536,7 +536,7 @@ encrypt_sign(struct context *c, bool comp_frag) * has not yet succeeded. In non-TLS tls_multi mode is not defined * and we always pass packets. */ - if (c->c2.tls_multi && c->c2.tls_multi->multi_state != CAS_SUCCEEDED) + if (c->c2.tls_multi && c->c2.tls_multi->multi_state < CAS_CONNECT_DONE) { c->c2.buf.len = 0; } @@ -971,7 +971,7 @@ process_incoming_link_part1(struct context *c, struct link_socket_info *lsi, boo * has not yet succeeded. In non-TLS mode tls_multi is not defined * and we always pass packets. */ - if (c->c2.tls_multi && c->c2.tls_multi->multi_state != CAS_SUCCEEDED) + if (c->c2.tls_multi && c->c2.tls_multi->multi_state < CAS_CONNECT_DONE) { c->c2.buf.len = 0; } diff --git a/src/openvpn/forward.h b/src/openvpn/forward.h index e27fcf7c5..c9d9de7a4 100644 --- a/src/openvpn/forward.h +++ b/src/openvpn/forward.h @@ -411,6 +411,17 @@ io_wait(struct context *c, const unsigned int flags) } } -#define CONNECTION_ESTABLISHED(c) (get_link_socket_info(c)->connection_established) +static inline bool +connection_established(struct context *c) +{ + if (c->c2.tls_multi) + { + return c->c2.tls_multi->multi_state >= CAS_CONNECT_DONE; + } + else + { + return get_link_socket_info(c)->connection_established; + } +} #endif /* FORWARD_H */ diff --git a/src/openvpn/multi.c b/src/openvpn/multi.c index 82c388698..52b177c1b 100644 --- a/src/openvpn/multi.c +++ b/src/openvpn/multi.c @@ -674,7 +674,8 @@ multi_close_instance(struct multi_context *m, #ifdef ENABLE_MANAGEMENT set_cc_config(mi, NULL); #endif - if (mi->context.c2.tls_multi->multi_state == CAS_SUCCEEDED) + + if (mi->context.c2.tls_multi->multi_state >= CAS_CONNECT_DONE) { multi_client_disconnect_script(mi); } @@ -775,7 +776,7 @@ multi_create_instance(struct multi_context *m, const struct mroute_addr *real) goto err; } - mi->context.c2.tls_multi->multi_state = CAS_PENDING; + mi->context.c2.tls_multi->multi_state = CAS_NOT_CONNECTED; if (hash_n_elements(m->hash) >= m->max_clients) { @@ -2407,7 +2408,7 @@ multi_client_connect_late_setup(struct multi_context *m, mi->reporting_addr_ipv6 = mi->context.c2.push_ifconfig_ipv6_local; /* set context-level authentication flag */ - mi->context.c2.tls_multi->multi_state = CAS_SUCCEEDED; + mi->context.c2.tls_multi->multi_state = CAS_CONNECT_DONE; /* authentication complete, calculate dynamic client specific options */ if (!multi_client_set_protocol_options(&mi->context)) @@ -2649,9 +2650,9 @@ multi_connection_established(struct multi_context *m, struct multi_instance *mi) case CC_RET_DEFERRED: /* - * we already set client_connect_status to DEFERRED_RESULT or + * we already set multi_status to DEFERRED_RESULT or * DEFERRED_NO_RESULT. We just return - * from the function as having client_connect_status + * from the function as having multi_status */ return; @@ -3003,8 +3004,8 @@ multi_process_post(struct multi_context *m, struct multi_instance *mi, const uns { /* connection is "established" when SSL/TLS key negotiation succeeds * and (if specified) auth user/pass succeeds */ - if (is_cas_pending(mi->context.c2.tls_multi->multi_state) - && CONNECTION_ESTABLISHED(&mi->context)) + + if (is_cas_pending(mi->context.c2.tls_multi->multi_state)) { multi_connection_established(m, mi); } diff --git a/src/openvpn/occ.c b/src/openvpn/occ.c index 3a2bcabe3..610c05f5f 100644 --- a/src/openvpn/occ.c +++ b/src/openvpn/occ.c @@ -185,7 +185,7 @@ check_send_occ_req_dowork(struct context *c) void check_send_occ_load_test_dowork(struct context *c) { - if (CONNECTION_ESTABLISHED(c)) + if (connection_established(c)) { const struct mtu_load_test *entry; diff --git a/src/openvpn/openvpn.h b/src/openvpn/openvpn.h index 3fe43180c..f925f1f67 100644 --- a/src/openvpn/openvpn.h +++ b/src/openvpn/openvpn.h @@ -206,7 +206,7 @@ struct context_1 static inline bool -is_cas_pending(enum client_connect_status cas) +is_cas_pending(enum multi_status cas) { return cas == CAS_PENDING || cas == CAS_PENDING_DEFERRED || cas == CAS_PENDING_DEFERRED_PARTIAL; @@ -237,6 +237,8 @@ struct context_2 struct link_socket *link_socket; /* socket used for TCP/UDP connection to remote */ bool link_socket_owned; + + /** This variable is used instead link_socket->info for P2MP UDP childs */ struct link_socket_info *link_socket_info; const struct link_socket *accept_from; /* possibly do accept() on a parent link_socket */ diff --git a/src/openvpn/push.c b/src/openvpn/push.c index 098b890eb..f3a0054a9 100644 --- a/src/openvpn/push.c +++ b/src/openvpn/push.c @@ -867,7 +867,7 @@ process_incoming_push_request(struct context *c) send_auth_failed(c, client_reason); ret = PUSH_MSG_AUTH_FAILURE; } - else if (c->c2.tls_multi->multi_state == CAS_SUCCEEDED) + else if (c->c2.tls_multi->multi_state >= CAS_CONNECT_DONE) { time_t now; diff --git a/src/openvpn/ssl.c b/src/openvpn/ssl.c index 7caeb209d..3fd2cefb5 100644 --- a/src/openvpn/ssl.c +++ b/src/openvpn/ssl.c @@ -2381,19 +2381,22 @@ key_method_2_write(struct buffer *buf, struct tls_multi *multi, struct tls_sessi * If we're a p2mp server to allow NCP, the first key * generation is postponed until after the connect script finished and the * NCP options can be processed. Since that always happens at after connect - * script options are available the CAS_SUCCEEDED status is identical to - * NCP options are processed and we have no extra state for NCP finished. + * script options are available the CAS_CONNECT_DONE status is identical to + * NCP options are processed and do not wait for NCP being finished. */ - if (session->opt->server && (session->opt->mode != MODE_SERVER - || multi->multi_state == CAS_SUCCEEDED)) + if (ks->authenticated > KS_AUTH_FALSE && session->opt->server + && ((session->opt->mode == MODE_SERVER && multi->multi_state >= CAS_CONNECT_DONE) + || (session->opt->mode == MODE_POINT_TO_POINT && !session->opt->pull))) { - if (ks->authenticated > KS_AUTH_FALSE) + /* if key_id >= 1, is a renegotiation, so we use the already established + * parameters and do not need to delay anything. */ + + /* key-id == 0 and multi_state >= CAS_CONNECT_DONE is a special case of + * the server reusing the session of a reconnecting client. */ + if (!tls_session_generate_data_channel_keys(session)) { - if (!tls_session_generate_data_channel_keys(session)) - { - msg(D_TLS_ERRORS, "TLS Error: server generate_key_expansion failed"); - goto error; - } + msg(D_TLS_ERRORS, "TLS Error: server generate_key_expansion failed"); + goto error; } } @@ -2801,6 +2804,21 @@ tls_process(struct tls_multi *multi, /* Set outgoing address for data channel packets */ link_socket_set_outgoing_addr(to_link_socket_info, &ks->remote_addr, session->common_name, session->opt->es); + /* Check if we need to advance the tls_multi state machine */ + if (multi->multi_state == CAS_NOT_CONNECTED) + { + if (session->opt->mode == MODE_SERVER) + { + /* On a server we continue with running connect scripts next */ + multi->multi_state = CAS_PENDING; + } + else + { + /* Skip the connect script related states */ + multi->multi_state = CAS_CONNECT_DONE; + } + } + /* Flush any payload packets that were buffered before our state transitioned to S_ACTIVE */ flush_payload_buffer(ks); diff --git a/src/openvpn/ssl_common.h b/src/openvpn/ssl_common.h index 845d2243d..ded86050d 100644 --- a/src/openvpn/ssl_common.h +++ b/src/openvpn/ssl_common.h @@ -504,12 +504,18 @@ struct tls_session /* client authentication state, CAS_SUCCEEDED must be 0 since * non multi code path still checks this variable but does not initialise it * so the code depends on zero initialisation */ -enum client_connect_status { - CAS_SUCCEEDED=0, + +/* CAS_NOT_CONNECTED is the initial state for every context. When the *first* + * tls_session reaches S_ACTIVE, this state machine moves to CAS_PENDING (server) + * or CAS_CONNECT_DONE (client/p2p) as clients skip the stages associated with + * connect scripts/plugins */ +enum multi_status { + CAS_NOT_CONNECTED, CAS_PENDING, CAS_PENDING_DEFERRED, CAS_PENDING_DEFERRED_PARTIAL, /**< at least handler succeeded, no result yet*/ CAS_FAILED, + CAS_CONNECT_DONE, }; @@ -548,7 +554,7 @@ struct tls_multi int n_sessions; /**< Number of sessions negotiated thus * far. */ - enum client_connect_status multi_state; + enum multi_status multi_state; /* * Number of errors.