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 1.54 2000/10/11 20:27:24 markus Exp $"); */ 16 /* $FreeBSD$ */ 17 18 #ifndef SSH_H 19 #define SSH_H 20 21 #include "rsa.h" 22 #include "cipher.h" 23 24 /* Cipher used for encrypting authentication files. */ 25 #define SSH_AUTHFILE_CIPHER SSH_CIPHER_3DES 26 27 /* Default port number. */ 28 #define SSH_DEFAULT_PORT 22 29 30 /* Maximum number of TCP/IP ports forwarded per direction. */ 31 #define SSH_MAX_FORWARDS_PER_DIRECTION 100 32 33 /* 34 * Maximum number of RSA authentication identity files that can be specified 35 * in configuration files or on the command line. 36 */ 37 #define SSH_MAX_IDENTITY_FILES 100 38 39 /* 40 * Major protocol version. Different version indicates major incompatiblity 41 * that prevents communication. 42 * 43 * Minor protocol version. Different version indicates minor incompatibility 44 * that does not prevent interoperation. 45 */ 46 #define PROTOCOL_MAJOR_1 1 47 #define PROTOCOL_MINOR_1 5 48 49 /* We support both SSH1 and SSH2 */ 50 #define PROTOCOL_MAJOR_2 2 51 #define PROTOCOL_MINOR_2 0 52 53 /* 54 * Name for the service. The port named by this service overrides the 55 * default port if present. 56 */ 57 #define SSH_SERVICE_NAME "ssh" 58 59 #define ETCDIR "/etc/ssh" 60 #define PIDDIR "/var/run" 61 62 /* 63 * System-wide file containing host keys of known hosts. This file should be 64 * world-readable. 65 */ 66 #define SSH_SYSTEM_HOSTFILE ETCDIR "/ssh_known_hosts" 67 #define SSH_SYSTEM_HOSTFILE2 ETCDIR "/ssh_known_hosts2" 68 69 /* 70 * Of these, ssh_host_key must be readable only by root, whereas ssh_config 71 * should be world-readable. 72 */ 73 #define HOST_KEY_FILE ETCDIR "/ssh_host_key" 74 #define SERVER_CONFIG_FILE ETCDIR "/sshd_config" 75 #define HOST_CONFIG_FILE ETCDIR "/ssh_config" 76 #define HOST_DSA_KEY_FILE ETCDIR "/ssh_host_dsa_key" 77 #define DH_PRIMES ETCDIR "/primes" 78 79 #define SSH_PROGRAM "/usr/bin/ssh" 80 81 /* 82 * The process id of the daemon listening for connections is saved here to 83 * make it easier to kill the correct daemon when necessary. 84 */ 85 #define SSH_DAEMON_PID_FILE PIDDIR "/sshd.pid" 86 87 /* 88 * The directory in user\'s home directory in which the files reside. The 89 * directory should be world-readable (though not all files are). 90 */ 91 #define SSH_USER_DIR ".ssh" 92 93 /* 94 * Per-user file containing host keys of known hosts. This file need not be 95 * readable by anyone except the user him/herself, though this does not 96 * contain anything particularly secret. 97 */ 98 #define SSH_USER_HOSTFILE "~/.ssh/known_hosts" 99 #define SSH_USER_HOSTFILE2 "~/.ssh/known_hosts2" 100 101 /* 102 * Name of the default file containing client-side authentication key. This 103 * file should only be readable by the user him/herself. 104 */ 105 #define SSH_CLIENT_IDENTITY ".ssh/identity" 106 #define SSH_CLIENT_ID_DSA ".ssh/id_dsa" 107 108 /* 109 * Configuration file in user\'s home directory. This file need not be 110 * readable by anyone but the user him/herself, but does not contain anything 111 * particularly secret. If the user\'s home directory resides on an NFS 112 * volume where root is mapped to nobody, this may need to be world-readable. 113 */ 114 #define SSH_USER_CONFFILE ".ssh/config" 115 116 /* 117 * File containing a list of those rsa keys that permit logging in as this 118 * user. This file need not be readable by anyone but the user him/herself, 119 * but does not contain anything particularly secret. If the user\'s home 120 * directory resides on an NFS volume where root is mapped to nobody, this 121 * may need to be world-readable. (This file is read by the daemon which is 122 * running as root.) 123 */ 124 #define SSH_USER_PERMITTED_KEYS ".ssh/authorized_keys" 125 #define SSH_USER_PERMITTED_KEYS2 ".ssh/authorized_keys2" 126 127 /* 128 * Per-user and system-wide ssh "rc" files. These files are executed with 129 * /bin/sh before starting the shell or command if they exist. They will be 130 * passed "proto cookie" as arguments if X11 forwarding with spoofing is in 131 * use. xauth will be run if neither of these exists. 132 */ 133 #define SSH_USER_RC ".ssh/rc" 134 #define SSH_SYSTEM_RC ETCDIR "/sshrc" 135 136 /* 137 * Ssh-only version of /etc/hosts.equiv. Additionally, the daemon may use 138 * ~/.rhosts and /etc/hosts.equiv if rhosts authentication is enabled. 139 */ 140 #define SSH_HOSTS_EQUIV ETCDIR "/shosts.equiv" 141 142 /* 143 * Name of the environment variable containing the pathname of the 144 * authentication socket. 145 */ 146 #define SSH_AUTHSOCKET_ENV_NAME "SSH_AUTH_SOCK" 147 148 /* 149 * Name of the environment variable containing the pathname of the 150 * authentication socket. 151 */ 152 #define SSH_AGENTPID_ENV_NAME "SSH_AGENT_PID" 153 154 /* 155 * Default path to ssh-askpass used by ssh-add, 156 * environment variable for overwriting the default location 157 */ 158 #define SSH_ASKPASS_DEFAULT "/usr/X11R6/bin/ssh-askpass" 159 #define SSH_ASKPASS_ENV "SSH_ASKPASS" 160 161 /* 162 * Force host key length and server key length to differ by at least this 163 * many bits. This is to make double encryption with rsaref work. 164 */ 165 #define SSH_KEY_BITS_RESERVED 128 166 167 /* 168 * Length of the session key in bytes. (Specified as 256 bits in the 169 * protocol.) 170 */ 171 #define SSH_SESSION_KEY_LENGTH 32 172 173 /* Name of Kerberos service for SSH to use. */ 174 #define KRB4_SERVICE_NAME "rcmd" 175 176 /* 177 * Authentication methods. New types can be added, but old types should not 178 * be removed for compatibility. The maximum allowed value is 31. 179 */ 180 #define SSH_AUTH_RHOSTS 1 181 #define SSH_AUTH_RSA 2 182 #define SSH_AUTH_PASSWORD 3 183 #define SSH_AUTH_RHOSTS_RSA 4 184 #define SSH_AUTH_TIS 5 185 #define SSH_AUTH_KRB4 6 186 #define SSH_PASS_KRB4_TGT 7 187 /* 8 to 15 are reserved */ 188 #define SSH_PASS_AFS_TOKEN 21 189 190 #define SSH_AUTH_KRB5 29 191 #define SSH_PASS_KRB5_TGT 30 192 193 /* Protocol flags. These are bit masks. */ 194 #define SSH_PROTOFLAG_SCREEN_NUMBER 1 /* X11 forwarding includes screen */ 195 #define SSH_PROTOFLAG_HOST_IN_FWD_OPEN 2 /* forwarding opens contain host */ 196 197 /* 198 * Definition of message types. New values can be added, but old values 199 * should not be removed or without careful consideration of the consequences 200 * for compatibility. The maximum value is 254; value 255 is reserved for 201 * future extension. 202 */ 203 /* Message name */ /* msg code */ /* arguments */ 204 #define SSH_MSG_NONE 0 /* no message */ 205 #define SSH_MSG_DISCONNECT 1 /* cause (string) */ 206 #define SSH_SMSG_PUBLIC_KEY 2 /* ck,msk,srvk,hostk */ 207 #define SSH_CMSG_SESSION_KEY 3 /* key (BIGNUM) */ 208 #define SSH_CMSG_USER 4 /* user (string) */ 209 #define SSH_CMSG_AUTH_RHOSTS 5 /* user (string) */ 210 #define SSH_CMSG_AUTH_RSA 6 /* modulus (BIGNUM) */ 211 #define SSH_SMSG_AUTH_RSA_CHALLENGE 7 /* int (BIGNUM) */ 212 #define SSH_CMSG_AUTH_RSA_RESPONSE 8 /* int (BIGNUM) */ 213 #define SSH_CMSG_AUTH_PASSWORD 9 /* pass (string) */ 214 #define SSH_CMSG_REQUEST_PTY 10 /* TERM, tty modes */ 215 #define SSH_CMSG_WINDOW_SIZE 11 /* row,col,xpix,ypix */ 216 #define SSH_CMSG_EXEC_SHELL 12 /* */ 217 #define SSH_CMSG_EXEC_CMD 13 /* cmd (string) */ 218 #define SSH_SMSG_SUCCESS 14 /* */ 219 #define SSH_SMSG_FAILURE 15 /* */ 220 #define SSH_CMSG_STDIN_DATA 16 /* data (string) */ 221 #define SSH_SMSG_STDOUT_DATA 17 /* data (string) */ 222 #define SSH_SMSG_STDERR_DATA 18 /* data (string) */ 223 #define SSH_CMSG_EOF 19 /* */ 224 #define SSH_SMSG_EXITSTATUS 20 /* status (int) */ 225 #define SSH_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* channel (int) */ 226 #define SSH_MSG_CHANNEL_OPEN_FAILURE 22 /* channel (int) */ 227 #define SSH_MSG_CHANNEL_DATA 23 /* ch,data (int,str) */ 228 #define SSH_MSG_CHANNEL_CLOSE 24 /* channel (int) */ 229 #define SSH_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* channel (int) */ 230 /* SSH_CMSG_X11_REQUEST_FORWARDING 26 OBSOLETE */ 231 #define SSH_SMSG_X11_OPEN 27 /* channel (int) */ 232 #define SSH_CMSG_PORT_FORWARD_REQUEST 28 /* p,host,hp (i,s,i) */ 233 #define SSH_MSG_PORT_OPEN 29 /* ch,h,p (i,s,i) */ 234 #define SSH_CMSG_AGENT_REQUEST_FORWARDING 30 /* */ 235 #define SSH_SMSG_AGENT_OPEN 31 /* port (int) */ 236 #define SSH_MSG_IGNORE 32 /* string */ 237 #define SSH_CMSG_EXIT_CONFIRMATION 33 /* */ 238 #define SSH_CMSG_X11_REQUEST_FORWARDING 34 /* proto,data (s,s) */ 239 #define SSH_CMSG_AUTH_RHOSTS_RSA 35 /* user,mod (s,mpi) */ 240 #define SSH_MSG_DEBUG 36 /* string */ 241 #define SSH_CMSG_REQUEST_COMPRESSION 37 /* level 1-9 (int) */ 242 #define SSH_CMSG_MAX_PACKET_SIZE 38 /* size 4k-1024k (int) */ 243 #define SSH_CMSG_AUTH_TIS 39 /* we use this for s/key */ 244 #define SSH_SMSG_AUTH_TIS_CHALLENGE 40 /* challenge (string) */ 245 #define SSH_CMSG_AUTH_TIS_RESPONSE 41 /* response (string) */ 246 #define SSH_CMSG_AUTH_KRB4 42 /* (KTEXT) */ 247 #define SSH_SMSG_AUTH_KRB4_RESPONSE 43 /* (KTEXT) */ 248 #define SSH_CMSG_HAVE_KRB4_TGT 44 /* credentials (s) */ 249 #define SSH_CMSG_HAVE_AFS_TOKEN 65 /* token (s) */ 250 251 #define SSH_CMSG_AUTH_KRB5 110 252 #define SSH_SMSG_AUTH_KRB5_RESPONSE 111 253 #define SSH_CMSG_HAVE_KRB5_TGT 112 254 255 /*------------ definitions for login.c -------------*/ 256 257 /* 258 * Returns the time when the user last logged in. Returns 0 if the 259 * information is not available. This must be called before record_login. 260 * The host from which the user logged in is stored in buf. 261 */ 262 unsigned long 263 get_last_login_time(uid_t uid, const char *logname, 264 char *buf, unsigned int bufsize); 265 266 /* 267 * Records that the user has logged in. This does many things normally done 268 * by login(1). 269 */ 270 void 271 record_login(pid_t pid, const char *ttyname, const char *user, uid_t uid, 272 const char *host, struct sockaddr *addr); 273 274 /* 275 * Records that the user has logged out. This does many thigs normally done 276 * by login(1) or init. 277 */ 278 void record_logout(pid_t pid, const char *ttyname); 279 280 /*------------ definitions for sshconnect.c ----------*/ 281 282 /* 283 * Opens a TCP/IP connection to the remote server on the given host. If port 284 * is 0, the default port will be used. If anonymous is zero, a privileged 285 * port will be allocated to make the connection. This requires super-user 286 * privileges if anonymous is false. Connection_attempts specifies the 287 * maximum number of tries, one per second. This returns true on success, 288 * and zero on failure. If the connection is successful, this calls 289 * packet_set_connection for the connection. 290 */ 291 int 292 ssh_connect(char **host, struct sockaddr_storage * hostaddr, 293 u_short port, int connection_attempts, 294 int anonymous, uid_t original_real_uid, 295 const char *proxy_command); 296 297 /* 298 * Starts a dialog with the server, and authenticates the current user on the 299 * server. This does not need any extra privileges. The basic connection to 300 * the server must already have been established before this is called. If 301 * login fails, this function prints an error and never returns. This 302 * initializes the random state, and leaves it initialized (it will also have 303 * references from the packet module). 304 */ 305 306 void 307 ssh_login(int host_key_valid, RSA * host_key, const char *host, 308 struct sockaddr * hostaddr, uid_t original_real_uid); 309 310 /*------------ Definitions for various authentication methods. -------*/ 311 312 /* 313 * Tries to authenticate the user using the .rhosts file. Returns true if 314 * authentication succeeds. If ignore_rhosts is non-zero, this will not 315 * consider .rhosts and .shosts (/etc/hosts.equiv will still be used). 316 */ 317 int auth_rhosts(struct passwd * pw, const char *client_user); 318 319 /* 320 * Tries to authenticate the user using the .rhosts file and the host using 321 * its host key. Returns true if authentication succeeds. 322 */ 323 int 324 auth_rhosts_rsa(struct passwd * pw, const char *client_user, RSA* client_host_key); 325 326 /* 327 * Tries to authenticate the user using password. Returns true if 328 * authentication succeeds. 329 */ 330 int auth_password(struct passwd * pw, const char *password); 331 332 /* 333 * Performs the RSA authentication dialog with the client. This returns 0 if 334 * the client could not be authenticated, and 1 if authentication was 335 * successful. This may exit if there is a serious protocol violation. 336 */ 337 int auth_rsa(struct passwd * pw, BIGNUM * client_n); 338 339 /* 340 * Parses an RSA key (number of bits, e, n) from a string. Moves the pointer 341 * over the key. Skips any whitespace at the beginning and at end. 342 */ 343 int auth_rsa_read_key(char **cpp, unsigned int *bitsp, BIGNUM * e, BIGNUM * n); 344 345 /* 346 * Returns the name of the machine at the other end of the socket. The 347 * returned string should be freed by the caller. 348 */ 349 char *get_remote_hostname(int socket); 350 351 /* 352 * Return the canonical name of the host in the other side of the current 353 * connection (as returned by packet_get_connection). The host name is 354 * cached, so it is efficient to call this several times. 355 */ 356 const char *get_canonical_hostname(void); 357 358 /* 359 * Returns the local IP address as an ascii string. 360 */ 361 const char *get_ipaddr(int socket); 362 363 /* 364 * Returns the remote IP address as an ascii string. The value need not be 365 * freed by the caller. 366 */ 367 const char *get_remote_ipaddr(void); 368 369 /* Returns the port number of the peer of the socket. */ 370 int get_peer_port(int sock); 371 372 /* Returns the port number of the remote/local host. */ 373 int get_remote_port(void); 374 int get_local_port(void); 375 376 377 /* 378 * Performs the RSA authentication challenge-response dialog with the client, 379 * and returns true (non-zero) if the client gave the correct answer to our 380 * challenge; returns zero if the client gives a wrong answer. 381 */ 382 int auth_rsa_challenge_dialog(RSA *pk); 383 384 /* 385 * Reads a passphrase from /dev/tty with echo turned off. Returns the 386 * passphrase (allocated with xmalloc). Exits if EOF is encountered. If 387 * from_stdin is true, the passphrase will be read from stdin instead. 388 */ 389 char *read_passphrase(char *prompt, int from_stdin); 390 391 392 /*------------ Definitions for logging. -----------------------*/ 393 394 /* Supported syslog facilities and levels. */ 395 typedef enum { 396 SYSLOG_FACILITY_DAEMON, 397 SYSLOG_FACILITY_USER, 398 SYSLOG_FACILITY_AUTH, 399 SYSLOG_FACILITY_LOCAL0, 400 SYSLOG_FACILITY_LOCAL1, 401 SYSLOG_FACILITY_LOCAL2, 402 SYSLOG_FACILITY_LOCAL3, 403 SYSLOG_FACILITY_LOCAL4, 404 SYSLOG_FACILITY_LOCAL5, 405 SYSLOG_FACILITY_LOCAL6, 406 SYSLOG_FACILITY_LOCAL7 407 } SyslogFacility; 408 409 typedef enum { 410 SYSLOG_LEVEL_QUIET, 411 SYSLOG_LEVEL_FATAL, 412 SYSLOG_LEVEL_ERROR, 413 SYSLOG_LEVEL_INFO, 414 SYSLOG_LEVEL_VERBOSE, 415 SYSLOG_LEVEL_DEBUG1, 416 SYSLOG_LEVEL_DEBUG2, 417 SYSLOG_LEVEL_DEBUG3 418 } LogLevel; 419 /* Initializes logging. */ 420 void log_init(char *av0, LogLevel level, SyslogFacility facility, int on_stderr); 421 422 /* Logging implementation, depending on server or client */ 423 void do_log(LogLevel level, const char *fmt, va_list args); 424 425 /* name to facility/level */ 426 SyslogFacility log_facility_number(char *name); 427 LogLevel log_level_number(char *name); 428 429 /* Output a message to syslog or stderr */ 430 void fatal(const char *fmt,...) __attribute__((format(printf, 1, 2))); 431 void error(const char *fmt,...) __attribute__((format(printf, 1, 2))); 432 void log(const char *fmt,...) __attribute__((format(printf, 1, 2))); 433 void verbose(const char *fmt,...) __attribute__((format(printf, 1, 2))); 434 void debug(const char *fmt,...) __attribute__((format(printf, 1, 2))); 435 void debug2(const char *fmt,...) __attribute__((format(printf, 1, 2))); 436 void debug3(const char *fmt,...) __attribute__((format(printf, 1, 2))); 437 438 /* same as fatal() but w/o logging */ 439 void fatal_cleanup(void); 440 441 /* 442 * Registers a cleanup function to be called by fatal()/fatal_cleanup() 443 * before exiting. It is permissible to call fatal_remove_cleanup for the 444 * function itself from the function. 445 */ 446 void fatal_add_cleanup(void (*proc) (void *context), void *context); 447 448 /* Removes a cleanup function to be called at fatal(). */ 449 void fatal_remove_cleanup(void (*proc) (void *context), void *context); 450 451 /* ---- misc */ 452 453 /* 454 * Expands tildes in the file name. Returns data allocated by xmalloc. 455 * Warning: this calls getpw*. 456 */ 457 char *tilde_expand_filename(const char *filename, uid_t my_uid); 458 459 /* remove newline at end of string */ 460 char *chop(char *s); 461 462 /* return next token in configuration line */ 463 char *strdelim(char **s); 464 465 /* set filedescriptor to non-blocking */ 466 void set_nonblock(int fd); 467 468 /* 469 * Performs the interactive session. This handles data transmission between 470 * the client and the program. Note that the notion of stdin, stdout, and 471 * stderr in this function is sort of reversed: this function writes to stdin 472 * (of the child program), and reads from stdout and stderr (of the child 473 * program). 474 */ 475 void server_loop(pid_t pid, int fdin, int fdout, int fderr); 476 void server_loop2(void); 477 478 /* Client side main loop for the interactive session. */ 479 int client_loop(int have_pty, int escape_char, int id); 480 481 /* Linked list of custom environment strings (see auth-rsa.c). */ 482 struct envstring { 483 struct envstring *next; 484 char *s; 485 }; 486 487 /* 488 * Ensure all of data on socket comes through. f==read || f==write 489 */ 490 ssize_t atomicio(ssize_t (*f)(), int fd, void *s, size_t n); 491 492 #ifdef KRB5 493 #include <krb5.h> 494 int auth_krb5(); /* XXX Doplnit prototypy */ 495 int auth_krb5_tgt(); 496 int krb5_init(); 497 void krb5_cleanup_proc(void *ignore); 498 int auth_krb5_password(struct passwd *pw, const char *password); 499 #endif /* KRB5 */ 500 501 #ifdef KRB4 502 #include <krb.h> 503 /* 504 * Performs Kerberos v4 mutual authentication with the client. This returns 0 505 * if the client could not be authenticated, and 1 if authentication was 506 * successful. This may exit if there is a serious protocol violation. 507 */ 508 int auth_krb4(const char *server_user, KTEXT auth, char **client); 509 int krb4_init(uid_t uid); 510 void krb4_cleanup_proc(void *ignore); 511 int auth_krb4_password(struct passwd * pw, const char *password); 512 513 #ifdef AFS 514 #include <kafs.h> 515 516 /* Accept passed Kerberos v4 ticket-granting ticket and AFS tokens. */ 517 int auth_krb4_tgt(struct passwd * pw, const char *string); 518 int auth_afs_token(struct passwd * pw, const char *token_string); 519 520 int creds_to_radix(CREDENTIALS * creds, unsigned char *buf, size_t buflen); 521 int radix_to_creds(const char *buf, CREDENTIALS * creds); 522 #endif /* AFS */ 523 524 #endif /* KRB4 */ 525 526 #ifdef SKEY 527 #include <opie.h> 528 char *skey_fake_keyinfo(char *username); 529 int auth_skey_password(struct passwd * pw, const char *password); 530 #endif /* SKEY */ 531 532 /* AF_UNSPEC or AF_INET or AF_INET6 */ 533 extern int IPv4or6; 534 535 #ifdef USE_PAM 536 #include "auth-pam.h" 537 #endif /* USE_PAM */ 538 539 #endif /* SSH_H */ 540