/* * OpenVPN -- An application to securely tunnel IP networks * over a single TCP/UDP port, with support for SSL/TLS-based * session authentication and key exchange, * packet encryption, packet authentication, and * packet compression. * * Copyright (C) 2002-2010 OpenVPN Technologies, Inc. * Copyright (C) 2010 Fox Crypto B.V. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 * as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program (see the file COPYING included with this * distribution); if not, write to the Free Software Foundation, Inc., * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ /** * @file Control Channel Common Data Structures */ #ifndef SSL_COMMON_H_ #define SSL_COMMON_H_ #include "session_id.h" #include "socket.h" #include "packet_id.h" #include "crypto.h" #include "options.h" #include "ssl_backend.h" /* passwords */ #define UP_TYPE_AUTH "Auth" #define UP_TYPE_PRIVATE_KEY "Private Key" /** @addtogroup control_processor * @{ */ /** * @name Control channel negotiation states * * These states represent the different phases of control channel * negotiation between OpenVPN peers. OpenVPN servers and clients * progress through the states in a different order, because of their * different roles during exchange of random material. The references to * the \c key_source2 structure in the list below is only valid if %key * method 2 is being used. See the \link key_generation data channel key * generation\endlink related page for more information. * * Clients follow this order: * -# \c S_INITIAL, ready to begin three-way handshake and control * channel negotiation. * -# \c S_PRE_START, have started three-way handshake, waiting for * acknowledgment from remote. * -# \c S_START, initial three-way handshake complete. * -# \c S_SENT_KEY, have sent local part of \c key_source2 random * material. * -# \c S_GOT_KEY, have received remote part of \c key_source2 random * material. * -# \c S_ACTIVE, normal operation during remaining handshake window. * -# \c S_NORMAL_OP, normal operation. * * Servers follow the same order, except for \c S_SENT_KEY and \c * S_GOT_KEY being reversed, because the server first receives the * client's \c key_source2 random material before generating and sending * its own. * * @{ */ #define S_ERROR -1 /**< Error state. */ #define S_UNDEF 0 /**< Undefined state, used after a \c * key_state is cleaned up. */ #define S_INITIAL 1 /**< Initial \c key_state state after * initialization by \c key_state_init() * before start of three-way handshake. */ #define S_PRE_START 2 /**< Waiting for the remote OpenVPN peer * to acknowledge during the initial * three-way handshake. */ #define S_START 3 /**< Three-way handshake is complete, * start of key exchange. */ #define S_SENT_KEY 4 /**< Local OpenVPN process has sent its * part of the key material. */ #define S_GOT_KEY 5 /**< Local OpenVPN process has received * the remote's part of the key * material. */ #define S_ACTIVE 6 /**< Operational \c key_state state * immediately after negotiation has * completed while still within the * handshake window. */ /* ready to exchange data channel packets */ #define S_NORMAL_OP 7 /**< Normal operational \c key_state * state. */ /** @} name Control channel negotiation states */ /** @} addtogroup control_processor */ /** * Container for one half of random material to be used in %key method 2 * \ref key_generation "data channel key generation". * @ingroup control_processor */ struct key_source { uint8_t pre_master[48]; /**< Random used for master secret * generation, provided only by client * OpenVPN peer. */ uint8_t random1[32]; /**< Seed used for master secret * generation, provided by both client * and server. */ uint8_t random2[32]; /**< Seed used for key expansion, provided * by both client and server. */ }; /** * Container for both halves of random material to be used in %key method * 2 \ref key_generation "data channel key generation". * @ingroup control_processor */ struct key_source2 { struct key_source client; /**< Random provided by client. */ struct key_source server; /**< Random provided by server. */ }; /** * Security parameter state of one TLS and data channel %key session. * @ingroup control_processor * * This structure represents one security parameter session between * OpenVPN peers. It includes the control channel TLS state and the data * channel crypto state. It also contains the reliability layer * structures used for control channel messages. * * A new \c key_state structure is initialized for each hard or soft * reset. * * @see * - This structure should be initialized using the \c key_state_init() * function. * - This structure should be cleaned up using the \c key_state_free() * function. */ struct key_state { int state; int key_id; /* inherited from struct tls_session below */ struct key_state_ssl ks_ssl; /* contains SSL object and BIOs for the control channel */ time_t established; /* when our state went S_ACTIVE */ time_t must_negotiate; /* key negotiation times out if not finished before this time */ time_t must_die; /* this object is destroyed at this time */ int initial_opcode; /* our initial P_ opcode */ struct session_id session_id_remote; /* peer's random session ID */ struct link_socket_actual remote_addr; /* peer's IP addr */ struct packet_id packet_id; /* for data channel, to prevent replay attacks */ struct key_ctx_bi key; /* data channel keys for encrypt/decrypt/hmac */ struct key_source2 *key_src; /* source entropy for key expansion */ struct buffer plaintext_read_buf; struct buffer plaintext_write_buf; struct buffer ack_write_buf; struct reliable *send_reliable; /* holds a copy of outgoing packets until ACK received */ struct reliable *rec_reliable; /* order incoming ciphertext packets before we pass to TLS */ struct reliable_ack *rec_ack; /* buffers all packet IDs we want to ACK back to sender */ struct buffer_list *paybuf; counter_type n_bytes; /* how many bytes sent/recvd since last key exchange */ counter_type n_packets; /* how many packets sent/recvd since last key exchange */ /* * If bad username/password, TLS connection will come up but 'authenticated' will be false. */ bool authenticated; time_t auth_deferred_expire; #ifdef ENABLE_DEF_AUTH /* If auth_deferred is true, authentication is being deferred */ bool auth_deferred; #ifdef MANAGEMENT_DEF_AUTH unsigned int mda_key_id; unsigned int mda_status; #endif #ifdef PLUGIN_DEF_AUTH unsigned int auth_control_status; time_t acf_last_mod; char *auth_control_file; #endif #endif }; /* * Our const options, obtained directly or derived from * command line options. */ struct tls_options { /* our master TLS context from which all SSL objects derived */ struct tls_root_ctx ssl_ctx; /* data channel cipher, hmac, and key lengths */ struct key_type key_type; /* true if we are a TLS server, client otherwise */ bool server; /* if true, don't xmit until first packet from peer is received */ bool xmit_hold; #ifdef ENABLE_OCC /* local and remote options strings that must match between client and server */ const char *local_options; const char *remote_options; #endif /* from command line */ int key_method; bool replay; bool single_session; #ifdef ENABLE_OCC bool disable_occ; #endif #ifdef ENABLE_PUSH_PEER_INFO int push_peer_info_detail; #endif int transition_window; int handshake_window; interval_t packet_timeout; int renegotiate_bytes; int renegotiate_packets; interval_t renegotiate_seconds; /* cert verification parms */ const char *verify_command; const char *verify_export_cert; int verify_x509_type; const char *verify_x509_name; const char *crl_file; int ns_cert_type; unsigned remote_cert_ku[MAX_PARMS]; const char *remote_cert_eku; uint8_t *verify_hash; char *x509_username_field; /* allow openvpn config info to be passed over control channel */ bool pass_config_info; /* struct crypto_option flags */ unsigned int crypto_flags_and; unsigned int crypto_flags_or; int replay_window; /* --replay-window parm */ int replay_time; /* --replay-window parm */ bool tcp_mode; /* packet authentication for TLS handshake */ struct crypto_options tls_auth; struct key_ctx_bi tls_auth_key; /* frame parameters for TLS control channel */ struct frame frame; /* used for username/password authentication */ const char *auth_user_pass_verify_script; bool auth_user_pass_verify_script_via_file; const char *tmp_dir; const char *auth_user_pass_file; /* use the client-config-dir as a positive authenticator */ const char *client_config_dir_exclusive; /* instance-wide environment variable set */ struct env_set *es; const struct plugin_list *plugins; /* compression parms */ #ifdef USE_COMP struct compress_options comp_options; #endif /* configuration file SSL-related boolean and low-permutation options */ # define SSLF_CLIENT_CERT_NOT_REQUIRED (1<<0) # define SSLF_USERNAME_AS_COMMON_NAME (1<<1) # define SSLF_AUTH_USER_PASS_OPTIONAL (1<<2) # define SSLF_OPT_VERIFY (1<<4) # define SSLF_CRL_VERIFY_DIR (1<<5) # define SSLF_TLS_VERSION_MIN_SHIFT 6 # define SSLF_TLS_VERSION_MIN_MASK 0xF /* (uses bit positions 6 to 9) */ # define SSLF_TLS_VERSION_MAX_SHIFT 10 # define SSLF_TLS_VERSION_MAX_MASK 0xF /* (uses bit positions 10 to 13) */ unsigned int ssl_flags; #ifdef MANAGEMENT_DEF_AUTH struct man_def_auth_context *mda_context; #endif #ifdef ENABLE_X509_TRACK const struct x509_track *x509_track; #endif #ifdef ENABLE_CLIENT_CR const struct static_challenge_info *sci; #endif /* --gremlin bits */ int gremlin; /* Keying Material Exporter [RFC 5705] parameters */ const char *ekm_label; size_t ekm_label_size; size_t ekm_size; }; /** @addtogroup control_processor * @{ */ /** @name Index of key_state objects within a tls_session structure * * This is the index of \c tls_session.key * * @{ */ #define KS_PRIMARY 0 /**< Primary %key state index. */ #define KS_LAME_DUCK 1 /**< %Key state index that will retire * soon. */ #define KS_SIZE 2 /**< Size of the \c tls_session.key array. */ /** @} name Index of key_state objects within a tls_session structure */ /** @} addtogroup control_processor */ /** * Security parameter state of a single session within a VPN tunnel. * @ingroup control_processor * * This structure represents an OpenVPN peer-to-peer control channel * session. * * A \c tls_session remains over soft resets, but a new instance is * initialized for each hard reset. * * @see * - This structure should be initialized using the \c tls_session_init() * function. * - This structure should be cleaned up using the \c tls_session_free() * function. */ struct tls_session { /* const options and config info */ struct tls_options *opt; /* during hard reset used to control burst retransmit */ bool burst; /* authenticate control packets */ struct crypto_options tls_auth; struct packet_id tls_auth_pid; int initial_opcode; /* our initial P_ opcode */ struct session_id session_id; /* our random session ID */ int key_id; /* increments with each soft reset (for key renegotiation) */ int limit_next; /* used for traffic shaping on the control channel */ int verify_maxlevel; char *common_name; struct cert_hash_set *cert_hash_set; #ifdef ENABLE_PF uint32_t common_name_hashval; #endif bool verified; /* true if peer certificate was verified against CA */ /* not-yet-authenticated incoming client */ struct link_socket_actual untrusted_addr; struct key_state key[KS_SIZE]; }; /** @addtogroup control_processor * @{ */ /** @name Index of tls_session objects within a tls_multi structure * * This is the index of \c tls_multi.session * * Normally three tls_session objects are maintained by an active openvpn * session. The first is the current, TLS authenticated session, the * second is used to process connection requests from a new client that * would usurp the current session if successfully authenticated, and the * third is used as a repository for a "lame-duck" %key in the event that * the primary session resets due to error while the lame-duck %key still * has time left before its expiration. Lame duck keys are used to * maintain the continuity of the data channel connection while a new %key * is being negotiated. * * @{ */ #define TM_ACTIVE 0 /**< Active \c tls_session. */ #define TM_UNTRUSTED 1 /**< As yet un-trusted \c tls_session * being negotiated. */ #define TM_LAME_DUCK 2 /**< Old \c tls_session. */ #define TM_SIZE 3 /**< Size of the \c tls_multi.session * array. */ /** @} name Index of tls_session objects within a tls_multi structure */ /** @} addtogroup control_processor */ /* * The number of keys we will scan on encrypt or decrypt. The first * is the "active" key. The second is the lame_duck or retiring key * associated with the active key's session ID. The third is a detached * lame duck session that only occurs in situations where a key renegotiate * failed on the active key, but a lame duck key was still valid. By * preserving the lame duck session, we can be assured of having a data * channel key available even when network conditions are so bad that * we can't negotiate a new key within the time allotted. */ #define KEY_SCAN_SIZE 3 /** * Security parameter state for a single VPN tunnel. * @ingroup control_processor * * An active VPN tunnel running with TLS enabled has one \c tls_multi * object, in which it stores all control channel and data channel * security parameter state. This structure can contain multiple, * possibly simultaneously active, \c tls_context objects to allow for * interruption-less transitions during session renegotiations. Each \c * tls_context represents one control channel session, which can span * multiple data channel security parameter sessions stored in \c * key_state structures. */ struct tls_multi { /* used to coordinate access between main thread and TLS thread */ /*MUTEX_PTR_DEFINE (mutex);*/ /* const options and config info */ struct tls_options opt; struct key_state* key_scan[KEY_SCAN_SIZE]; /**< List of \c key_state objects in the * order they should be scanned by data * channel modules. */ /* * used by tls_pre_encrypt to communicate the encrypt key * to tls_post_encrypt() */ struct key_state *save_ks; /* temporary pointer used between pre/post routines */ /* * Used to return outgoing address from * tls_multi_process. */ struct link_socket_actual to_link_addr; int n_sessions; /**< Number of sessions negotiated thus * far. */ /* * Number of errors. */ int n_hard_errors; /* errors due to TLS negotiation failure */ int n_soft_errors; /* errors due to unrecognized or failed-to-authenticate incoming packets */ /* * Our locked common name, username, and cert hashes (cannot change during the life of this tls_multi object) */ char *locked_cn; char *locked_username; struct cert_hash_set *locked_cert_hash_set; #ifdef ENABLE_DEF_AUTH /* * An error message to send to client on AUTH_FAILED */ char *client_reason; /* Time of last call to tls_authentication_status */ time_t tas_last; #endif #if P2MP_SERVER /* * A multi-line string of general-purpose info received from peer * over control channel. */ char *peer_info; #endif /* For P_DATA_V2 */ uint32_t peer_id; bool use_peer_id; /* * Our session objects. */ struct tls_session session[TM_SIZE]; /**< Array of \c tls_session objects * representing control channel * sessions with the remote peer. */ }; #define SHOW_TLS_CIPHER_LIST_WARNING \ "Be aware that that whether a cipher suite in this list can actually work\n" \ "depends on the specific setup of both peers. See the man page entries of\n" \ "--tls-cipher and --show-tls for more details.\n\n" #endif /* SSL_COMMON_H_ */