From fffd213c8cba2135afda493d797c41c10354770e Mon Sep 17 00:00:00 2001 From: Othmar Gsenger Date: Sat, 12 Apr 2008 11:38:42 +0000 Subject: big svn cleanup --- openvpn/ssl.h | 690 ---------------------------------------------------------- 1 file changed, 690 deletions(-) delete mode 100644 openvpn/ssl.h (limited to 'openvpn/ssl.h') diff --git a/openvpn/ssl.h b/openvpn/ssl.h deleted file mode 100644 index e07f19a..0000000 --- a/openvpn/ssl.h +++ /dev/null @@ -1,690 +0,0 @@ -/* - * 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) 2002-2005 OpenVPN Solutions LLC - * - * 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 - */ - -#ifndef OPENVPN_SSL_H -#define OPENVPN_SSL_H - -#if defined(USE_CRYPTO) && defined(USE_SSL) - -#include -#include -#include -#include -#include -#include - -#include "basic.h" -#include "common.h" -#include "crypto.h" -#include "packet_id.h" -#include "session_id.h" -#include "reliable.h" -#include "socket.h" -#include "mtu.h" -#include "thread.h" -#include "options.h" -#include "plugin.h" - -/* - * OpenVPN Protocol, taken from ssl.h in OpenVPN source code. - * - * TCP/UDP Packet: This represents the top-level encapsulation. - * - * TCP/UDP packet format: - * - * Packet length (16 bits, unsigned) -- TCP only, always sent as - * plaintext. Since TCP is a stream protocol, the packet - * length words define the packetization of the stream. - * - * Packet opcode/key_id (8 bits) -- TLS only, not used in - * pre-shared secret mode. - * packet message type, a P_* constant (high 5 bits) - * key_id (low 3 bits, see key_id in struct tls_session - * below for comment). The key_id refers to an - * already negotiated TLS session. OpenVPN seamlessly - * renegotiates the TLS session by using a new key_id - * for the new session. Overlap (controlled by - * user definable parameters) between old and new TLS - * sessions is allowed, providing a seamless transition - * during tunnel operation. - * - * Payload (n bytes), which may be a P_CONTROL, P_ACK, or P_DATA - * message. - * - * Message types: - * - * P_CONTROL_HARD_RESET_CLIENT_V1 -- Key method 1, initial key from - * client, forget previous state. - * - * P_CONTROL_HARD_RESET_SERVER_V1 -- Key method 2, initial key - * from server, forget previous state. - * - * P_CONTROL_SOFT_RESET_V1 -- New key, with a graceful transition - * from old to new key in the sense that a transition window - * exists where both the old or new key_id can be used. OpenVPN - * uses two different forms of key_id. The first form is 64 bits - * and is used for all P_CONTROL messages. P_DATA messages on the - * other hand use a shortened key_id of 3 bits for efficiency - * reasons since the vast majority of OpenVPN packets in an - * active tunnel will be P_DATA messages. The 64 bit form - * is referred to as a session_id, while the 3 bit form is - * referred to as a key_id. - * - * P_CONTROL_V1 -- Control channel packet (usually TLS ciphertext). - * - * P_ACK_V1 -- Acknowledgement for P_CONTROL packets received. - * - * P_DATA_V1 -- Data channel packet containing actual tunnel data - * ciphertext. - * - * P_CONTROL_HARD_RESET_CLIENT_V2 -- Key method 2, initial key from - * client, forget previous state. - * - * P_CONTROL_HARD_RESET_SERVER_V2 -- Key method 2, initial key from - * server, forget previous state. - * - * P_CONTROL* and P_ACK Payload: The P_CONTROL message type - * indicates a TLS ciphertext packet which has been encapsulated - * inside of a reliability layer. The reliability layer is - * implemented as a straightforward ACK and retransmit model. - * - * P_CONTROL message format: - * - * local session_id (random 64 bit value to identify TLS session). - * HMAC signature of entire encapsulation header for integrity - * check if --tls-auth is specified (usually 16 or 20 bytes). - * packet-id for replay protection (4 or 8 bytes, includes - * sequence number and optional time_t timestamp). - * P_ACK packet_id array length (1 byte). - * P_ACK packet-id array (if length > 0). - * P_ACK remote session_id (if length > 0). - * message packet-id (4 bytes). - * TLS payload ciphertext (n bytes) (only for P_CONTROL). - * - * Once the TLS session has been initialized and authenticated, - * the TLS channel is used to exchange random key material for - * bidirectional cipher and HMAC keys which will be - * used to secure actual tunnel packets. OpenVPN currently - * implements two key methods. Key method 1 directly - * derives keys using random bits obtained from the RAND_bytes - * OpenSSL function. Key method 2 mixes random key material - * from both sides of the connection using the TLS PRF mixing - * function. Key method 2 is the preferred method and is the default - * for OpenVPN 2.0. - * - * TLS plaintext content: - * - * TLS plaintext packet (if key_method == 1): - * - * Cipher key length in bytes (1 byte). - * Cipher key (n bytes). - * HMAC key length in bytes (1 byte). - * HMAC key (n bytes). - * Options string (n bytes, null terminated, client/server options - * string should match). - * - * TLS plaintext packet (if key_method == 2): - * - * Literal 0 (4 bytes). - * key_method type (1 byte). - * key_source structure (pre_master only defined for client -> - * server). - * options_string_length, including null (2 bytes). - * Options string (n bytes, null terminated, client/server options - * string must match). - * [The username/password data below is optional, record can end - * at this point.] - * username_string_length, including null (2 bytes). - * Username string (n bytes, null terminated). - * password_string_length, including null (2 bytes). - * Password string (n bytes, null terminated). - * - * The P_DATA payload represents encrypted, encapsulated tunnel - * packets which tend to be either IP packets or Ethernet frames. - * This is essentially the "payload" of the VPN. - * - * P_DATA message content: - * HMAC of ciphertext IV + ciphertext (if not disabled by - * --auth none). - * Ciphertext IV (size is cipher-dependent, if not disabled by - * --no-iv). - * Tunnel packet ciphertext. - * - * P_DATA plaintext - * packet_id (4 or 8 bytes, if not disabled by --no-replay). - * In SSL/TLS mode, 4 bytes are used because the implementation - * can force a TLS renegotation before 2^32 packets are sent. - * In pre-shared key mode, 8 bytes are used (sequence number - * and time_t value) to allow long-term key usage without - * packet_id collisions. - * User plaintext (n bytes). - * - * Notes: - * (1) ACK messages can be encoded in either the dedicated - * P_ACK record or they can be prepended to a P_CONTROL message. - * (2) P_DATA and P_CONTROL/P_ACK use independent packet-id - * sequences because P_DATA is an unreliable channel while - * P_CONTROL/P_ACK is a reliable channel. Each use their - * own independent HMAC keys. - * (3) Note that when --tls-auth is used, all message types are - * protected with an HMAC signature, even the initial packets - * of the TLS handshake. This makes it easy for OpenVPN to - * throw away bogus packets quickly, without wasting resources - * on attempting a TLS handshake which will ultimately fail. - */ - -/* Used in the TLS PRF function */ -#define KEY_EXPANSION_ID "OpenVPN" - -/* passwords */ -#define UP_TYPE_AUTH "Auth" -#define UP_TYPE_PRIVATE_KEY "Private Key" - -/* packet opcode (high 5 bits) and key-id (low 3 bits) are combined in one byte */ -#define P_KEY_ID_MASK 0x07 -#define P_OPCODE_SHIFT 3 - -/* packet opcodes -- the V1 is intended to allow protocol changes in the future */ -#define P_CONTROL_HARD_RESET_CLIENT_V1 1 /* initial key from client, forget previous state */ -#define P_CONTROL_HARD_RESET_SERVER_V1 2 /* initial key from server, forget previous state */ -#define P_CONTROL_SOFT_RESET_V1 3 /* new key, graceful transition from old to new key */ -#define P_CONTROL_V1 4 /* control channel packet (usually TLS ciphertext) */ -#define P_ACK_V1 5 /* acknowledgement for packets received */ -#define P_DATA_V1 6 /* data channel packet */ - -/* indicates key_method >= 2 */ -#define P_CONTROL_HARD_RESET_CLIENT_V2 7 /* initial key from client, forget previous state */ -#define P_CONTROL_HARD_RESET_SERVER_V2 8 /* initial key from server, forget previous state */ - -/* define the range of legal opcodes */ -#define P_FIRST_OPCODE 1 -#define P_LAST_OPCODE 8 - -/* key negotiation states */ -#define S_ERROR -1 -#define S_UNDEF 0 -#define S_INITIAL 1 /* tls_init() was called */ -#define S_PRE_START 2 /* waiting for initial reset & acknowledgement */ -#define S_START 3 /* ready to exchange keys */ -#define S_SENT_KEY 4 /* client does S_SENT_KEY -> S_GOT_KEY */ -#define S_GOT_KEY 5 /* server does S_GOT_KEY -> S_SENT_KEY */ -#define S_ACTIVE 6 /* ready to exchange data channel packets */ -#define S_NORMAL 7 /* normal operations */ - -/* - * Are we ready to receive data channel packets? - * - * Also, if true, we can safely assume session has been - * authenticated by TLS. - * - * NOTE: Assumes S_SENT_KEY + 1 == S_GOT_KEY. - */ -#define DECRYPT_KEY_ENABLED(multi, ks) ((ks)->state >= (S_GOT_KEY - (multi)->opt.server)) - -/* Should we aggregate TLS acknowledgements, and tack them onto control packets? */ -#define TLS_AGGREGATE_ACK - -/* - * If TLS_AGGREGATE_ACK, set the - * max number of acknowledgments that - * can "hitch a ride" on an outgoing - * non-P_ACK_V1 control packet. - */ -#define CONTROL_SEND_ACK_MAX 4 - -/* - * Define number of buffers for send and receive in the reliability layer. - */ -#define TLS_RELIABLE_N_SEND_BUFFERS 4 /* also window size for reliablity layer */ -#define TLS_RELIABLE_N_REC_BUFFERS 8 - -/* - * Various timeouts - */ - -#define TLS_MULTI_REFRESH 15 /* call tls_multi_process once every n seconds */ -#define TLS_MULTI_HORIZON 2 /* call tls_multi_process frequently for n seconds after - every packet sent/received action */ - -/* The SSL/TLS worker thread will wait at most this many seconds for the interprocess - communication pipe to the main thread to be ready to accept writes. */ -#define TLS_MULTI_THREAD_SEND_TIMEOUT 5 - -/* - * Buffer sizes (also see mtu.h). - */ - -#define PLAINTEXT_BUFFER_SIZE TLS_CHANNEL_BUF_SIZE - -/* Maximum length of common name */ -#define TLS_CN_LEN 64 - -/* Legal characters in an X509 or common name */ -#define X509_NAME_CHAR_CLASS (CC_ALNUM|CC_UNDERBAR|CC_DASH|CC_DOT|CC_AT|CC_COLON|CC_SLASH|CC_EQUAL) -#define COMMON_NAME_CHAR_CLASS (CC_ALNUM|CC_UNDERBAR|CC_DASH|CC_DOT|CC_AT) - -/* Maximum length of OCC options string passed as part of auth handshake */ -#define TLS_OPTIONS_LEN 512 - -/* - * Range of key exchange methods - */ -#define KEY_METHOD_MIN 1 -#define KEY_METHOD_MAX 2 - -/* key method taken from lower 4 bits */ -#define KEY_METHOD_MASK 0x0F - -/* - * Measure success rate of TLS handshakes, for debugging only - */ -/* #define MEASURE_TLS_HANDSHAKE_STATS */ - -/* - * Key material, used as source for PRF-based - * key expansion. - */ - -struct key_source { - uint8_t pre_master[48]; /* client generated */ - uint8_t random1[32]; /* generated by both client and server */ - uint8_t random2[32]; /* generated by both client and server */ -}; - -struct key_source2 { - struct key_source client; - struct key_source server; -}; - -/* - * Represents a single instantiation of a TLS negotiation and - * data channel key exchange. 4 keys are kept: encrypt hmac, - * decrypt hmac, encrypt cipher, and decrypt cipher. The TLS - * control channel is used to exchange these keys. - * Each hard or soft reset will build - * a fresh key_state. Normally an openvpn session will contain two - * key_state objects, one for the current TLS connection, and other - * for the retiring or "lame duck" key. The lame duck key_state is - * used to maintain transmission continuity on the data-channel while - * a key renegotiation is taking place. - */ -struct key_state -{ - int state; - int key_id; /* inherited from struct tls_session below */ - - SSL *ssl; /* SSL object -- new obj created for each new key */ - BIO *ssl_bio; /* read/write plaintext from here */ - BIO *ct_in; /* write ciphertext to here */ - BIO *ct_out; /* read ciphertext from here */ - - 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 sockaddr_in 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 */ - - int n_bytes; /* how many bytes sent/recvd since last key exchange */ - int 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; -}; - -/* - * Our const options, obtained directly or derived from - * command line options. - */ -struct tls_options -{ - /* our master SSL_CTX from which all SSL objects derived */ - SSL_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; - -#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 - 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_x509name; - const char *crl_file; - int ns_cert_type; - - /* 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 */ - - /* 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; - bool username_as_common_name; - - /* 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; - - /* --gremlin bits */ - int gremlin; -}; - -/* index into tls_session.key */ -#define KS_PRIMARY 0 /* the primary key */ -#define KS_LAME_DUCK 1 /* the key that's going to retire soon */ -#define KS_SIZE 2 - -/* - * A tls_session lives through multiple key_state life-cycles. Soft resets - * will reuse a tls_session object, but hard resets or errors will require - * that a fresh object be built. 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. - */ -struct tls_session -{ - /* const options and config info */ - const 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; - bool verified; /* true if peer certificate was verified against CA */ - - /* not-yet-authenticated incoming client */ - struct sockaddr_in untrusted_sockaddr; - - struct key_state key[KS_SIZE]; -}; - -/* index into tls_multi.session */ -#define TM_ACTIVE 0 -#define TM_UNTRUSTED 1 -#define TM_LAME_DUCK 2 -#define TM_SIZE 3 - -/* - * 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 - -/* - * An openvpn session running with TLS enabled has one tls_multi object. - */ -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; - - /* - * A list of key_state objects in the order they should be - * scanned by data channel encrypt and decrypt routines. - */ - struct key_state* key_scan[KEY_SCAN_SIZE]; - - /* - * 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 */ - - /* - * Number of sessions negotiated thus far. - */ - int n_sessions; - - /* - * 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 (cannot change during the life of this tls_multi object) - */ - char *locked_cn; - - /* - * Our session objects. - */ - struct tls_session session[TM_SIZE]; -}; - -/* - * Used in --mode server mode to check tls-auth signature on initial - * packets received from new clients. - */ -struct tls_auth_standalone -{ - struct key_ctx_bi tls_auth_key; - struct crypto_options tls_auth_options; - struct frame frame; -}; - -void init_ssl_lib (void); -void free_ssl_lib (void); - -/* Build master SSL_CTX object that serves for the whole of openvpn instantiation */ -SSL_CTX *init_ssl (const struct options *options); - -struct tls_multi *tls_multi_init (struct tls_options *tls_options); - -struct tls_auth_standalone *tls_auth_standalone_init (struct tls_options *tls_options, - struct gc_arena *gc); - -void tls_auth_standalone_finalize (struct tls_auth_standalone *tas, - const struct frame *frame); - -void tls_multi_init_finalize(struct tls_multi *multi, - const struct frame *frame); - -void tls_multi_init_set_options(struct tls_multi* multi, - const char *local, - const char *remote); - -bool tls_multi_process (struct tls_multi *multi, - struct buffer *to_link, - struct sockaddr_in *to_link_addr, - struct link_socket_info *to_link_socket_info, - interval_t *wakeup); - -void tls_multi_free (struct tls_multi *multi, bool clear); - -bool tls_pre_decrypt (struct tls_multi *multi, - struct sockaddr_in *from, - struct buffer *buf, - struct crypto_options *opt); - -bool tls_pre_decrypt_lite (const struct tls_auth_standalone *tas, - const struct sockaddr_in *from, - const struct buffer *buf); - -void tls_pre_encrypt (struct tls_multi *multi, - struct buffer *buf, struct crypto_options *opt); - -void tls_post_encrypt (struct tls_multi *multi, struct buffer *buf); - -void show_available_tls_ciphers (void); -void get_highest_preference_tls_cipher (char *buf, int size); - -void pem_password_setup (const char *auth_file); -int pem_password_callback (char *buf, int size, int rwflag, void *u); -void auth_user_pass_setup (const char *auth_file); -void ssl_set_auth_nocache (void); -void ssl_purge_auth (void); - -void tls_set_verify_command (const char *cmd); -void tls_set_crl_verify (const char *crl); -void tls_set_verify_x509name (const char *x509name); - -void tls_adjust_frame_parameters(struct frame *frame); - -bool tls_send_payload (struct tls_multi *multi, - const uint8_t *data, - int size); - -bool tls_rec_payload (struct tls_multi *multi, - struct buffer *buf); - -const char *tls_common_name (struct tls_multi* multi, bool null); -void tls_set_common_name (struct tls_multi *multi, const char *common_name); -void tls_lock_common_name (struct tls_multi *multi); - -bool tls_authenticated (struct tls_multi *multi); -void tls_deauthenticate (struct tls_multi *multi); - -/* - * inline functions - */ - -static inline int -tls_test_payload_len (const struct tls_multi *multi) -{ - if (multi) - { - const struct key_state *ks = &multi->session[TM_ACTIVE].key[KS_PRIMARY]; - if (ks->state >= S_ACTIVE) - return BLEN (&ks->plaintext_read_buf); - } - return 0; -} - -static inline void -tls_set_single_session (struct tls_multi *multi) -{ - if (multi) - multi->opt.single_session = true; -} - -/* - * protocol_dump() flags - */ -#define PD_TLS_AUTH_HMAC_SIZE_MASK 0xFF -#define PD_SHOW_DATA (1<<8) -#define PD_TLS (1<<9) -#define PD_VERBOSE (1<<10) - -const char *protocol_dump (struct buffer *buffer, - unsigned int flags, - struct gc_arena *gc); - -/* - * debugging code - */ - -#ifdef MEASURE_TLS_HANDSHAKE_STATS -void show_tls_performance_stats(void); -#endif - -/*#define EXTRACT_X509_FIELD_TEST*/ -void extract_x509_field_test (void); - -#endif /* USE_CRYPTO && USE_SSL */ - -#endif -- cgit v1.2.3