1 /* 2 * Author: Tatu Ylonen <ylo@cs.hut.fi> 3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 4 * All rights reserved 5 * 6 * Generic header file for ssh. 7 * 8 * As far as I am concerned, the code I have written for this software 9 * can be used freely for any purpose. Any derived versions of this 10 * software must be clearly marked as such, and if the derived work is 11 * incompatible with the protocol description in the RFC file, it must be 12 * called by a name other than "ssh" or "Secure Shell". 13 */ 14 15 /* RCSID("$OpenBSD: ssh.h,v 1.50 2000/09/07 20:27:54 deraadt Exp $"); */ 16 /* $FreeBSD$ */ 17 18 #ifndef SSH_H 19 #define SSH_H 20 21 #include "rsa.h" 22 #include "cipher.h" 23 24 /* 25 * XXX 26 * The default cipher used if IDEA is not supported by the remote host. It is 27 * recommended that this be one of the mandatory ciphers (DES, 3DES), though 28 * that is not required. 29 */ 30 #define SSH_FALLBACK_CIPHER SSH_CIPHER_3DES 31 32 /* Cipher used for encrypting authentication files. */ 33 #define SSH_AUTHFILE_CIPHER SSH_CIPHER_3DES 34 35 /* Default port number. */ 36 #define SSH_DEFAULT_PORT 22 37 38 /* Maximum number of TCP/IP ports forwarded per direction. */ 39 #define SSH_MAX_FORWARDS_PER_DIRECTION 100 40 41 /* 42 * Maximum number of RSA authentication identity files that can be specified 43 * in configuration files or on the command line. 44 */ 45 #define SSH_MAX_IDENTITY_FILES 100 46 47 /* 48 * Major protocol version. Different version indicates major incompatiblity 49 * that prevents communication. 50 * 51 * Minor protocol version. Different version indicates minor incompatibility 52 * that does not prevent interoperation. 53 */ 54 #define PROTOCOL_MAJOR_1 1 55 #define PROTOCOL_MINOR_1 5 56 57 /* We support both SSH1 and SSH2 */ 58 #define PROTOCOL_MAJOR_2 2 59 #define PROTOCOL_MINOR_2 0 60 61 /* 62 * Name for the service. The port named by this service overrides the 63 * default port if present. 64 */ 65 #define SSH_SERVICE_NAME "ssh" 66 67 #define ETCDIR "/etc/ssh" 68 #define PIDDIR "/var/run" 69 70 /* 71 * System-wide file containing host keys of known hosts. This file should be 72 * world-readable. 73 */ 74 #define SSH_SYSTEM_HOSTFILE ETCDIR "/ssh_known_hosts" 75 #define SSH_SYSTEM_HOSTFILE2 ETCDIR "/ssh_known_hosts2" 76 77 /* 78 * Of these, ssh_host_key must be readable only by root, whereas ssh_config 79 * should be world-readable. 80 */ 81 #define HOST_KEY_FILE ETCDIR "/ssh_host_key" 82 #define SERVER_CONFIG_FILE ETCDIR "/sshd_config" 83 #define HOST_CONFIG_FILE ETCDIR "/ssh_config" 84 #define HOST_DSA_KEY_FILE ETCDIR "/ssh_host_dsa_key" 85 86 #define SSH_PROGRAM "/usr/bin/ssh" 87 88 /* 89 * The process id of the daemon listening for connections is saved here to 90 * make it easier to kill the correct daemon when necessary. 91 */ 92 #define SSH_DAEMON_PID_FILE PIDDIR "/sshd.pid" 93 94 /* 95 * The directory in user\'s home directory in which the files reside. The 96 * directory should be world-readable (though not all files are). 97 */ 98 #define SSH_USER_DIR ".ssh" 99 100 /* 101 * Per-user file containing host keys of known hosts. This file need not be 102 * readable by anyone except the user him/herself, though this does not 103 * contain anything particularly secret. 104 */ 105 #define SSH_USER_HOSTFILE "~/.ssh/known_hosts" 106 #define SSH_USER_HOSTFILE2 "~/.ssh/known_hosts2" 107 108 /* 109 * Name of the default file containing client-side authentication key. This 110 * file should only be readable by the user him/herself. 111 */ 112 #define SSH_CLIENT_IDENTITY ".ssh/identity" 113 #define SSH_CLIENT_ID_DSA ".ssh/id_dsa" 114 115 /* 116 * Configuration file in user\'s home directory. This file need not be 117 * readable by anyone but the user him/herself, but does not contain anything 118 * particularly secret. If the user\'s home directory resides on an NFS 119 * volume where root is mapped to nobody, this may need to be world-readable. 120 */ 121 #define SSH_USER_CONFFILE ".ssh/config" 122 123 /* 124 * File containing a list of those rsa keys that permit logging in as this 125 * user. This file need not be readable by anyone but the user him/herself, 126 * but does not contain anything particularly secret. If the user\'s home 127 * directory resides on an NFS volume where root is mapped to nobody, this 128 * may need to be world-readable. (This file is read by the daemon which is 129 * running as root.) 130 */ 131 #define SSH_USER_PERMITTED_KEYS ".ssh/authorized_keys" 132 #define SSH_USER_PERMITTED_KEYS2 ".ssh/authorized_keys2" 133 134 /* 135 * Per-user and system-wide ssh "rc" files. These files are executed with 136 * /bin/sh before starting the shell or command if they exist. They will be 137 * passed "proto cookie" as arguments if X11 forwarding with spoofing is in 138 * use. xauth will be run if neither of these exists. 139 */ 140 #define SSH_USER_RC ".ssh/rc" 141 #define SSH_SYSTEM_RC ETCDIR "/sshrc" 142 143 /* 144 * Ssh-only version of /etc/hosts.equiv. Additionally, the daemon may use 145 * ~/.rhosts and /etc/hosts.equiv if rhosts authentication is enabled. 146 */ 147 #define SSH_HOSTS_EQUIV ETCDIR "/shosts.equiv" 148 149 /* 150 * Name of the environment variable containing the pathname of the 151 * authentication socket. 152 */ 153 #define SSH_AUTHSOCKET_ENV_NAME "SSH_AUTH_SOCK" 154 155 /* 156 * Name of the environment variable containing the pathname of the 157 * authentication socket. 158 */ 159 #define SSH_AGENTPID_ENV_NAME "SSH_AGENT_PID" 160 161 /* 162 * Default path to ssh-askpass used by ssh-add, 163 * environment variable for overwriting the default location 164 */ 165 #define SSH_ASKPASS_DEFAULT "/usr/X11R6/bin/ssh-askpass" 166 #define SSH_ASKPASS_ENV "SSH_ASKPASS" 167 168 /* 169 * Force host key length and server key length to differ by at least this 170 * many bits. This is to make double encryption with rsaref work. 171 */ 172 #define SSH_KEY_BITS_RESERVED 128 173 174 /* 175 * Length of the session key in bytes. (Specified as 256 bits in the 176 * protocol.) 177 */ 178 #define SSH_SESSION_KEY_LENGTH 32 179 180 /* Name of Kerberos service for SSH to use. */ 181 #define KRB4_SERVICE_NAME "rcmd" 182 183 /* 184 * Authentication methods. New types can be added, but old types should not 185 * be removed for compatibility. The maximum allowed value is 31. 186 */ 187 #define SSH_AUTH_RHOSTS 1 188 #define SSH_AUTH_RSA 2 189 #define SSH_AUTH_PASSWORD 3 190 #define SSH_AUTH_RHOSTS_RSA 4 191 #define SSH_AUTH_TIS 5 192 #define SSH_AUTH_KRB4 6 193 #define SSH_PASS_KRB4_TGT 7 194 /* 8 to 15 are reserved */ 195 #define SSH_PASS_AFS_TOKEN 21 196 197 #define SSH_AUTH_KRB5 29 198 #define SSH_PASS_KRB5_TGT 30 199 200 /* Protocol flags. These are bit masks. */ 201 #define SSH_PROTOFLAG_SCREEN_NUMBER 1 /* X11 forwarding includes screen */ 202 #define SSH_PROTOFLAG_HOST_IN_FWD_OPEN 2 /* forwarding opens contain host */ 203 204 /* 205 * Definition of message types. New values can be added, but old values 206 * should not be removed or without careful consideration of the consequences 207 * for compatibility. The maximum value is 254; value 255 is reserved for 208 * future extension. 209 */ 210 /* Message name */ /* msg code */ /* arguments */ 211 #define SSH_MSG_NONE 0 /* no message */ 212 #define SSH_MSG_DISCONNECT 1 /* cause (string) */ 213 #define SSH_SMSG_PUBLIC_KEY 2 /* ck,msk,srvk,hostk */ 214 #define SSH_CMSG_SESSION_KEY 3 /* key (BIGNUM) */ 215 #define SSH_CMSG_USER 4 /* user (string) */ 216 #define SSH_CMSG_AUTH_RHOSTS 5 /* user (string) */ 217 #define SSH_CMSG_AUTH_RSA 6 /* modulus (BIGNUM) */ 218 #define SSH_SMSG_AUTH_RSA_CHALLENGE 7 /* int (BIGNUM) */ 219 #define SSH_CMSG_AUTH_RSA_RESPONSE 8 /* int (BIGNUM) */ 220 #define SSH_CMSG_AUTH_PASSWORD 9 /* pass (string) */ 221 #define SSH_CMSG_REQUEST_PTY 10 /* TERM, tty modes */ 222 #define SSH_CMSG_WINDOW_SIZE 11 /* row,col,xpix,ypix */ 223 #define SSH_CMSG_EXEC_SHELL 12 /* */ 224 #define SSH_CMSG_EXEC_CMD 13 /* cmd (string) */ 225 #define SSH_SMSG_SUCCESS 14 /* */ 226 #define SSH_SMSG_FAILURE 15 /* */ 227 #define SSH_CMSG_STDIN_DATA 16 /* data (string) */ 228 #define SSH_SMSG_STDOUT_DATA 17 /* data (string) */ 229 #define SSH_SMSG_STDERR_DATA 18 /* data (string) */ 230 #define SSH_CMSG_EOF 19 /* */ 231 #define SSH_SMSG_EXITSTATUS 20 /* status (int) */ 232 #define SSH_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* channel (int) */ 233 #define SSH_MSG_CHANNEL_OPEN_FAILURE 22 /* channel (int) */ 234 #define SSH_MSG_CHANNEL_DATA 23 /* ch,data (int,str) */ 235 #define SSH_MSG_CHANNEL_CLOSE 24 /* channel (int) */ 236 #define SSH_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* channel (int) */ 237 /* SSH_CMSG_X11_REQUEST_FORWARDING 26 OBSOLETE */ 238 #define SSH_SMSG_X11_OPEN 27 /* channel (int) */ 239 #define SSH_CMSG_PORT_FORWARD_REQUEST 28 /* p,host,hp (i,s,i) */ 240 #define SSH_MSG_PORT_OPEN 29 /* ch,h,p (i,s,i) */ 241 #define SSH_CMSG_AGENT_REQUEST_FORWARDING 30 /* */ 242 #define SSH_SMSG_AGENT_OPEN 31 /* port (int) */ 243 #define SSH_MSG_IGNORE 32 /* string */ 244 #define SSH_CMSG_EXIT_CONFIRMATION 33 /* */ 245 #define SSH_CMSG_X11_REQUEST_FORWARDING 34 /* proto,data (s,s) */ 246 #define SSH_CMSG_AUTH_RHOSTS_RSA 35 /* user,mod (s,mpi) */ 247 #define SSH_MSG_DEBUG 36 /* string */ 248 #define SSH_CMSG_REQUEST_COMPRESSION 37 /* level 1-9 (int) */ 249 #define SSH_CMSG_MAX_PACKET_SIZE 38 /* size 4k-1024k (int) */ 250 #define SSH_CMSG_AUTH_TIS 39 /* we use this for s/key */ 251 #define SSH_SMSG_AUTH_TIS_CHALLENGE 40 /* challenge (string) */ 252 #define SSH_CMSG_AUTH_TIS_RESPONSE 41 /* response (string) */ 253 #define SSH_CMSG_AUTH_KRB4 42 /* (KTEXT) */ 254 #define SSH_SMSG_AUTH_KRB4_RESPONSE 43 /* (KTEXT) */ 255 #define SSH_CMSG_HAVE_KRB4_TGT 44 /* credentials (s) */ 256 #define SSH_CMSG_HAVE_AFS_TOKEN 65 /* token (s) */ 257 258 #define SSH_CMSG_AUTH_KRB5 110 259 #define SSH_SMSG_AUTH_KRB5_RESPONSE 111 260 #define SSH_CMSG_HAVE_KRB5_TGT 112 261 262 /*------------ definitions for login.c -------------*/ 263 264 /* 265 * Returns the time when the user last logged in. Returns 0 if the 266 * information is not available. This must be called before record_login. 267 * The host from which the user logged in is stored in buf. 268 */ 269 unsigned long 270 get_last_login_time(uid_t uid, const char *logname, 271 char *buf, unsigned int bufsize); 272 273 /* 274 * Records that the user has logged in. This does many things normally done 275 * by login(1). 276 */ 277 void 278 record_login(pid_t pid, const char *ttyname, const char *user, uid_t uid, 279 const char *host, struct sockaddr *addr); 280 281 /* 282 * Records that the user has logged out. This does many thigs normally done 283 * by login(1) or init. 284 */ 285 void record_logout(pid_t pid, const char *ttyname); 286 287 /*------------ definitions for sshconnect.c ----------*/ 288 289 /* 290 * Opens a TCP/IP connection to the remote server on the given host. If port 291 * is 0, the default port will be used. If anonymous is zero, a privileged 292 * port will be allocated to make the connection. This requires super-user 293 * privileges if anonymous is false. Connection_attempts specifies the 294 * maximum number of tries, one per second. This returns true on success, 295 * and zero on failure. If the connection is successful, this calls 296 * packet_set_connection for the connection. 297 */ 298 int 299 ssh_connect(const char *host, struct sockaddr_storage * hostaddr, 300 u_short port, int connection_attempts, 301 int anonymous, uid_t original_real_uid, 302 const char *proxy_command); 303 304 /* 305 * Starts a dialog with the server, and authenticates the current user on the 306 * server. This does not need any extra privileges. The basic connection to 307 * the server must already have been established before this is called. If 308 * login fails, this function prints an error and never returns. This 309 * initializes the random state, and leaves it initialized (it will also have 310 * references from the packet module). 311 */ 312 313 void 314 ssh_login(int host_key_valid, RSA * host_key, const char *host, 315 struct sockaddr * hostaddr, uid_t original_real_uid); 316 317 /*------------ Definitions for various authentication methods. -------*/ 318 319 /* 320 * Tries to authenticate the user using the .rhosts file. Returns true if 321 * authentication succeeds. If ignore_rhosts is non-zero, this will not 322 * consider .rhosts and .shosts (/etc/hosts.equiv will still be used). 323 */ 324 int auth_rhosts(struct passwd * pw, const char *client_user); 325 326 /* 327 * Tries to authenticate the user using the .rhosts file and the host using 328 * its host key. Returns true if authentication succeeds. 329 */ 330 int 331 auth_rhosts_rsa(struct passwd * pw, const char *client_user, RSA* client_host_key); 332 333 /* 334 * Tries to authenticate the user using password. Returns true if 335 * authentication succeeds. 336 */ 337 int auth_password(struct passwd * pw, const char *password); 338 339 /* 340 * Performs the RSA authentication dialog with the client. This returns 0 if 341 * the client could not be authenticated, and 1 if authentication was 342 * successful. This may exit if there is a serious protocol violation. 343 */ 344 int auth_rsa(struct passwd * pw, BIGNUM * client_n); 345 346 /* 347 * Parses an RSA key (number of bits, e, n) from a string. Moves the pointer 348 * over the key. Skips any whitespace at the beginning and at end. 349 */ 350 int auth_rsa_read_key(char **cpp, unsigned int *bitsp, BIGNUM * e, BIGNUM * n); 351 352 /* 353 * Returns the name of the machine at the other end of the socket. The 354 * returned string should be freed by the caller. 355 */ 356 char *get_remote_hostname(int socket); 357 358 /* 359 * Return the canonical name of the host in the other side of the current 360 * connection (as returned by packet_get_connection). The host name is 361 * cached, so it is efficient to call this several times. 362 */ 363 const char *get_canonical_hostname(void); 364 365 /* 366 * Returns the local IP address as an ascii string. 367 */ 368 const char *get_ipaddr(int socket); 369 370 /* 371 * Returns the remote IP address as an ascii string. The value need not be 372 * freed by the caller. 373 */ 374 const char *get_remote_ipaddr(void); 375 376 /* Returns the port number of the peer of the socket. */ 377 int get_peer_port(int sock); 378 379 /* Returns the port number of the remote/local host. */ 380 int get_remote_port(void); 381 int get_local_port(void); 382 383 384 /* 385 * Performs the RSA authentication challenge-response dialog with the client, 386 * and returns true (non-zero) if the client gave the correct answer to our 387 * challenge; returns zero if the client gives a wrong answer. 388 */ 389 int auth_rsa_challenge_dialog(RSA *pk); 390 391 /* 392 * Reads a passphrase from /dev/tty with echo turned off. Returns the 393 * passphrase (allocated with xmalloc). Exits if EOF is encountered. If 394 * from_stdin is true, the passphrase will be read from stdin instead. 395 */ 396 char *read_passphrase(const char *prompt, int from_stdin); 397 398 399 /*------------ Definitions for logging. -----------------------*/ 400 401 /* Supported syslog facilities and levels. */ 402 typedef enum { 403 SYSLOG_FACILITY_DAEMON, 404 SYSLOG_FACILITY_USER, 405 SYSLOG_FACILITY_AUTH, 406 SYSLOG_FACILITY_LOCAL0, 407 SYSLOG_FACILITY_LOCAL1, 408 SYSLOG_FACILITY_LOCAL2, 409 SYSLOG_FACILITY_LOCAL3, 410 SYSLOG_FACILITY_LOCAL4, 411 SYSLOG_FACILITY_LOCAL5, 412 SYSLOG_FACILITY_LOCAL6, 413 SYSLOG_FACILITY_LOCAL7 414 } SyslogFacility; 415 416 typedef enum { 417 SYSLOG_LEVEL_QUIET, 418 SYSLOG_LEVEL_FATAL, 419 SYSLOG_LEVEL_ERROR, 420 SYSLOG_LEVEL_INFO, 421 SYSLOG_LEVEL_VERBOSE, 422 SYSLOG_LEVEL_DEBUG 423 } LogLevel; 424 /* Initializes logging. */ 425 void log_init(char *av0, LogLevel level, SyslogFacility facility, int on_stderr); 426 427 /* Logging implementation, depending on server or client */ 428 void do_log(LogLevel level, const char *fmt, va_list args); 429 430 /* name to facility/level */ 431 SyslogFacility log_facility_number(char *name); 432 LogLevel log_level_number(char *name); 433 434 /* Output a message to syslog or stderr */ 435 void fatal(const char *fmt,...) __attribute__((format(printf, 1, 2))); 436 void error(const char *fmt,...) __attribute__((format(printf, 1, 2))); 437 void log(const char *fmt,...) __attribute__((format(printf, 1, 2))); 438 void verbose(const char *fmt,...) __attribute__((format(printf, 1, 2))); 439 void debug(const char *fmt,...) __attribute__((format(printf, 1, 2))); 440 441 /* same as fatal() but w/o logging */ 442 void fatal_cleanup(void); 443 444 /* 445 * Registers a cleanup function to be called by fatal()/fatal_cleanup() 446 * before exiting. It is permissible to call fatal_remove_cleanup for the 447 * function itself from the function. 448 */ 449 void fatal_add_cleanup(void (*proc) (void *context), void *context); 450 451 /* Removes a cleanup function to be called at fatal(). */ 452 void fatal_remove_cleanup(void (*proc) (void *context), void *context); 453 454 /* ---- misc */ 455 456 /* 457 * Expands tildes in the file name. Returns data allocated by xmalloc. 458 * Warning: this calls getpw*. 459 */ 460 char *tilde_expand_filename(const char *filename, uid_t my_uid); 461 462 /* remove newline at end of string */ 463 char *chop(char *s); 464 465 /* return next token in configuration line */ 466 char *strdelim(char **s); 467 468 /* set filedescriptor to non-blocking */ 469 void set_nonblock(int fd); 470 471 /* 472 * Performs the interactive session. This handles data transmission between 473 * the client and the program. Note that the notion of stdin, stdout, and 474 * stderr in this function is sort of reversed: this function writes to stdin 475 * (of the child program), and reads from stdout and stderr (of the child 476 * program). 477 */ 478 void server_loop(pid_t pid, int fdin, int fdout, int fderr); 479 void server_loop2(void); 480 481 /* Client side main loop for the interactive session. */ 482 int client_loop(int have_pty, int escape_char, int id); 483 484 /* Linked list of custom environment strings (see auth-rsa.c). */ 485 struct envstring { 486 struct envstring *next; 487 char *s; 488 }; 489 490 /* 491 * Ensure all of data on socket comes through. f==read || f==write 492 */ 493 ssize_t atomicio(ssize_t (*f)(), int fd, void *s, size_t n); 494 495 #ifdef KRB5 496 #include <krb5.h> 497 int auth_krb5(); /* XXX Doplnit prototypy */ 498 int auth_krb5_tgt(); 499 int krb5_init(); 500 void krb5_cleanup_proc(void *ignore); 501 int auth_krb5_password(struct passwd *pw, const char *password); 502 #endif /* KRB5 */ 503 504 #ifdef KRB4 505 #include <krb.h> 506 /* 507 * Performs Kerberos v4 mutual authentication with the client. This returns 0 508 * if the client could not be authenticated, and 1 if authentication was 509 * successful. This may exit if there is a serious protocol violation. 510 */ 511 int auth_krb4(const char *server_user, KTEXT auth, char **client); 512 int krb4_init(uid_t uid); 513 void krb4_cleanup_proc(void *ignore); 514 int auth_krb4_password(struct passwd * pw, const char *password); 515 516 #ifdef AFS 517 #include <kafs.h> 518 519 /* Accept passed Kerberos v4 ticket-granting ticket and AFS tokens. */ 520 int auth_krb4_tgt(struct passwd * pw, const char *string); 521 int auth_afs_token(struct passwd * pw, const char *token_string); 522 523 int creds_to_radix(CREDENTIALS * creds, unsigned char *buf, size_t buflen); 524 int radix_to_creds(const char *buf, CREDENTIALS * creds); 525 #endif /* AFS */ 526 527 #endif /* KRB4 */ 528 529 #ifdef SKEY 530 #include <opie.h> 531 char *skey_fake_keyinfo(char *username); 532 int auth_skey_password(struct passwd * pw, const char *password); 533 #endif /* SKEY */ 534 535 /* AF_UNSPEC or AF_INET or AF_INET6 */ 536 extern int IPv4or6; 537 538 #endif /* SSH_H */ 539