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+/*
+ * 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. <sales@openvpn.net>
+ * Copyright (C) 2010 Fox Crypto B.V. <openvpn@fox-it.com>
+ *
+ * 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
+ bool push_peer_info;
+#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;
+ const char *verify_x509name;
+ 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;
+
+ /* 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;
+
+ /* configuration file boolean 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)
+ 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;
+};
+
+/** @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;
+
+ /*
+ * A multi-line string of general-purpose info received from peer
+ * over control channel.
+ */
+ char *peer_info;
+
+ /* Time of last call to tls_authentication_status */
+ time_t tas_last;
+#endif
+
+ /*
+ * Our session objects.
+ */
+ struct tls_session session[TM_SIZE];
+ /**< Array of \c tls_session objects
+ * representing control channel
+ * sessions with the remote peer. */
+};
+
+
+#endif /* SSL_COMMON_H_ */