2 * Author: Tatu Ylonen <ylo@cs.hut.fi>
3 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
6 * Generic header file for ssh.
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".
15 /* RCSID("$OpenBSD: ssh.h,v 1.55 2000/11/25 17:19:33 markus Exp $"); */
20 #include <netinet/in.h> /* For struct sockaddr_in */
21 #include <pwd.h> /* For struct pw */
22 #include <stdarg.h> /* For va_list */
23 #include <syslog.h> /* For LOG_AUTH and friends */
24 #include <sys/socket.h> /* For struct sockaddr_storage */
25 #include "fake-socket.h" /* For struct sockaddr_storage */
26 #ifdef HAVE_SYS_SELECT_H
27 # include <sys/select.h>
32 /* Cipher used for encrypting authentication files. */
33 #define SSH_AUTHFILE_CIPHER SSH_CIPHER_3DES
35 /* Default port number. */
36 #define SSH_DEFAULT_PORT 22
38 /* Maximum number of TCP/IP ports forwarded per direction. */
39 #define SSH_MAX_FORWARDS_PER_DIRECTION 100
42 * Maximum number of RSA authentication identity files that can be specified
43 * in configuration files or on the command line.
45 #define SSH_MAX_IDENTITY_FILES 100
48 * Major protocol version. Different version indicates major incompatiblity
49 * that prevents communication.
51 * Minor protocol version. Different version indicates minor incompatibility
52 * that does not prevent interoperation.
54 #define PROTOCOL_MAJOR_1 1
55 #define PROTOCOL_MINOR_1 5
57 /* We support both SSH1 and SSH2 */
58 #define PROTOCOL_MAJOR_2 2
59 #define PROTOCOL_MINOR_2 0
62 * Name for the service. The port named by this service overrides the
63 * default port if present.
65 #define SSH_SERVICE_NAME "ssh"
67 #if defined(USE_PAM) && !defined(SSHD_PAM_SERVICE)
68 # define SSHD_PAM_SERVICE "sshd"
76 #define PIDDIR "/var/run"
80 * System-wide file containing host keys of known hosts. This file should be
83 #define SSH_SYSTEM_HOSTFILE ETCDIR "/ssh_known_hosts"
84 #define SSH_SYSTEM_HOSTFILE2 ETCDIR "/ssh_known_hosts2"
87 * Of these, ssh_host_key must be readable only by root, whereas ssh_config
88 * should be world-readable.
90 #define HOST_KEY_FILE ETCDIR "/ssh_host_key"
91 #define SERVER_CONFIG_FILE ETCDIR "/sshd_config"
92 #define HOST_CONFIG_FILE ETCDIR "/ssh_config"
93 #define HOST_DSA_KEY_FILE ETCDIR "/ssh_host_dsa_key"
94 #define DH_PRIMES ETCDIR "/primes"
97 #define SSH_PROGRAM "/usr/bin/ssh"
98 #endif /* SSH_PROGRAM */
100 #ifndef LOGIN_PROGRAM
101 # ifdef LOGIN_PROGRAM_FALLBACK
102 # define LOGIN_PROGRAM LOGIN_PROGRAM_FALLBACK
104 # define LOGIN_PROGRAM "/usr/bin/login"
106 #endif /* LOGIN_PROGRAM */
108 #ifndef ASKPASS_PROGRAM
109 #define ASKPASS_PROGRAM "/usr/lib/ssh/ssh-askpass"
110 #endif /* ASKPASS_PROGRAM */
113 * The process id of the daemon listening for connections is saved here to
114 * make it easier to kill the correct daemon when necessary.
116 #define SSH_DAEMON_PID_FILE PIDDIR "/sshd.pid"
119 * The directory in user\'s home directory in which the files reside. The
120 * directory should be world-readable (though not all files are).
122 #define SSH_USER_DIR ".ssh"
125 * Relevant only when using builtin PRNG.
127 #ifndef SSH_PRNG_SEED_FILE
128 # define SSH_PRNG_SEED_FILE SSH_USER_DIR"/prng_seed"
129 #endif /* SSH_PRNG_SEED_FILE */
130 #ifndef SSH_PRNG_COMMAND_FILE
131 # define SSH_PRNG_COMMAND_FILE ETCDIR "/ssh_prng_cmds"
132 #endif /* SSH_PRNG_COMMAND_FILE */
135 * Per-user file containing host keys of known hosts. This file need not be
136 * readable by anyone except the user him/herself, though this does not
137 * contain anything particularly secret.
139 #define SSH_USER_HOSTFILE "~/.ssh/known_hosts"
140 #define SSH_USER_HOSTFILE2 "~/.ssh/known_hosts2"
143 * Name of the default file containing client-side authentication key. This
144 * file should only be readable by the user him/herself.
146 #define SSH_CLIENT_IDENTITY ".ssh/identity"
147 #define SSH_CLIENT_ID_DSA ".ssh/id_dsa"
148 #define SSH_CLIENT_ID_RSA ".ssh/id_rsa"
151 * Configuration file in user\'s home directory. This file need not be
152 * readable by anyone but the user him/herself, but does not contain anything
153 * particularly secret. If the user\'s home directory resides on an NFS
154 * volume where root is mapped to nobody, this may need to be world-readable.
156 #define SSH_USER_CONFFILE ".ssh/config"
159 * File containing a list of those rsa keys that permit logging in as this
160 * user. This file need not be readable by anyone but the user him/herself,
161 * but does not contain anything particularly secret. If the user\'s home
162 * directory resides on an NFS volume where root is mapped to nobody, this
163 * may need to be world-readable. (This file is read by the daemon which is
166 #define SSH_USER_PERMITTED_KEYS ".ssh/authorized_keys"
167 #define SSH_USER_PERMITTED_KEYS2 ".ssh/authorized_keys2"
170 * Per-user and system-wide ssh "rc" files. These files are executed with
171 * /bin/sh before starting the shell or command if they exist. They will be
172 * passed "proto cookie" as arguments if X11 forwarding with spoofing is in
173 * use. xauth will be run if neither of these exists.
175 #define SSH_USER_RC ".ssh/rc"
176 #define SSH_SYSTEM_RC ETCDIR "/sshrc"
179 * Ssh-only version of /etc/hosts.equiv. Additionally, the daemon may use
180 * ~/.rhosts and /etc/hosts.equiv if rhosts authentication is enabled.
182 #define SSH_HOSTS_EQUIV ETCDIR "/shosts.equiv"
185 * Name of the environment variable containing the pathname of the
186 * authentication socket.
188 #define SSH_AUTHSOCKET_ENV_NAME "SSH_AUTH_SOCK"
191 * Name of the environment variable containing the pathname of the
192 * authentication socket.
194 #define SSH_AGENTPID_ENV_NAME "SSH_AGENT_PID"
197 * Default path to ssh-askpass used by ssh-add,
198 * environment variable for overwriting the default location
200 #ifndef SSH_ASKPASS_DEFAULT
201 # define SSH_ASKPASS_DEFAULT "/usr/X11R6/bin/ssh-askpass"
203 #define SSH_ASKPASS_ENV "SSH_ASKPASS"
206 * Force host key length and server key length to differ by at least this
207 * many bits. This is to make double encryption with rsaref work.
209 #define SSH_KEY_BITS_RESERVED 128
212 * Length of the session key in bytes. (Specified as 256 bits in the
215 #define SSH_SESSION_KEY_LENGTH 32
217 /* Name of Kerberos service for SSH to use. */
218 #define KRB4_SERVICE_NAME "rcmd"
221 * Authentication methods. New types can be added, but old types should not
222 * be removed for compatibility. The maximum allowed value is 31.
224 #define SSH_AUTH_RHOSTS 1
225 #define SSH_AUTH_RSA 2
226 #define SSH_AUTH_PASSWORD 3
227 #define SSH_AUTH_RHOSTS_RSA 4
228 #define SSH_AUTH_TIS 5
229 #define SSH_AUTH_KERBEROS 6
230 #define SSH_PASS_KERBEROS_TGT 7
231 /* 8 to 15 are reserved */
232 #define SSH_PASS_AFS_TOKEN 21
234 /* Protocol flags. These are bit masks. */
235 #define SSH_PROTOFLAG_SCREEN_NUMBER 1 /* X11 forwarding includes screen */
236 #define SSH_PROTOFLAG_HOST_IN_FWD_OPEN 2 /* forwarding opens contain host */
239 * Definition of message types. New values can be added, but old values
240 * should not be removed or without careful consideration of the consequences
241 * for compatibility. The maximum value is 254; value 255 is reserved for
244 /* Message name */ /* msg code */ /* arguments */
245 #define SSH_MSG_NONE 0 /* no message */
246 #define SSH_MSG_DISCONNECT 1 /* cause (string) */
247 #define SSH_SMSG_PUBLIC_KEY 2 /* ck,msk,srvk,hostk */
248 #define SSH_CMSG_SESSION_KEY 3 /* key (BIGNUM) */
249 #define SSH_CMSG_USER 4 /* user (string) */
250 #define SSH_CMSG_AUTH_RHOSTS 5 /* user (string) */
251 #define SSH_CMSG_AUTH_RSA 6 /* modulus (BIGNUM) */
252 #define SSH_SMSG_AUTH_RSA_CHALLENGE 7 /* int (BIGNUM) */
253 #define SSH_CMSG_AUTH_RSA_RESPONSE 8 /* int (BIGNUM) */
254 #define SSH_CMSG_AUTH_PASSWORD 9 /* pass (string) */
255 #define SSH_CMSG_REQUEST_PTY 10 /* TERM, tty modes */
256 #define SSH_CMSG_WINDOW_SIZE 11 /* row,col,xpix,ypix */
257 #define SSH_CMSG_EXEC_SHELL 12 /* */
258 #define SSH_CMSG_EXEC_CMD 13 /* cmd (string) */
259 #define SSH_SMSG_SUCCESS 14 /* */
260 #define SSH_SMSG_FAILURE 15 /* */
261 #define SSH_CMSG_STDIN_DATA 16 /* data (string) */
262 #define SSH_SMSG_STDOUT_DATA 17 /* data (string) */
263 #define SSH_SMSG_STDERR_DATA 18 /* data (string) */
264 #define SSH_CMSG_EOF 19 /* */
265 #define SSH_SMSG_EXITSTATUS 20 /* status (int) */
266 #define SSH_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* channel (int) */
267 #define SSH_MSG_CHANNEL_OPEN_FAILURE 22 /* channel (int) */
268 #define SSH_MSG_CHANNEL_DATA 23 /* ch,data (int,str) */
269 #define SSH_MSG_CHANNEL_CLOSE 24 /* channel (int) */
270 #define SSH_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* channel (int) */
271 /* SSH_CMSG_X11_REQUEST_FORWARDING 26 OBSOLETE */
272 #define SSH_SMSG_X11_OPEN 27 /* channel (int) */
273 #define SSH_CMSG_PORT_FORWARD_REQUEST 28 /* p,host,hp (i,s,i) */
274 #define SSH_MSG_PORT_OPEN 29 /* ch,h,p (i,s,i) */
275 #define SSH_CMSG_AGENT_REQUEST_FORWARDING 30 /* */
276 #define SSH_SMSG_AGENT_OPEN 31 /* port (int) */
277 #define SSH_MSG_IGNORE 32 /* string */
278 #define SSH_CMSG_EXIT_CONFIRMATION 33 /* */
279 #define SSH_CMSG_X11_REQUEST_FORWARDING 34 /* proto,data (s,s) */
280 #define SSH_CMSG_AUTH_RHOSTS_RSA 35 /* user,mod (s,mpi) */
281 #define SSH_MSG_DEBUG 36 /* string */
282 #define SSH_CMSG_REQUEST_COMPRESSION 37 /* level 1-9 (int) */
283 #define SSH_CMSG_MAX_PACKET_SIZE 38 /* size 4k-1024k (int) */
284 #define SSH_CMSG_AUTH_TIS 39 /* we use this for s/key */
285 #define SSH_SMSG_AUTH_TIS_CHALLENGE 40 /* challenge (string) */
286 #define SSH_CMSG_AUTH_TIS_RESPONSE 41 /* response (string) */
287 #define SSH_CMSG_AUTH_KERBEROS 42 /* (KTEXT) */
288 #define SSH_SMSG_AUTH_KERBEROS_RESPONSE 43 /* (KTEXT) */
289 #define SSH_CMSG_HAVE_KERBEROS_TGT 44 /* credentials (s) */
290 #define SSH_CMSG_HAVE_AFS_TOKEN 65 /* token (s) */
292 /*------------ definitions for login.c -------------*/
295 * Returns the time when the user last logged in. Returns 0 if the
296 * information is not available. This must be called before record_login.
297 * The host from which the user logged in is stored in buf.
300 get_last_login_time(uid_t uid, const char *logname,
301 char *buf, unsigned int bufsize);
304 * Records that the user has logged in. This does many things normally done
308 record_login(pid_t pid, const char *ttyname, const char *user, uid_t uid,
309 const char *host, struct sockaddr *addr);
312 * Records that the user has logged out. This does many thigs normally done
313 * by login(1) or init.
315 void record_logout(pid_t pid, const char *ttyname);
317 /*------------ definitions for sshconnect.c ----------*/
320 * Opens a TCP/IP connection to the remote server on the given host. If port
321 * is 0, the default port will be used. If anonymous is zero, a privileged
322 * port will be allocated to make the connection. This requires super-user
323 * privileges if anonymous is false. Connection_attempts specifies the
324 * maximum number of tries, one per second. This returns true on success,
325 * and zero on failure. If the connection is successful, this calls
326 * packet_set_connection for the connection.
329 ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
330 u_short port, int connection_attempts,
331 int anonymous, uid_t original_real_uid,
332 const char *proxy_command);
335 * Starts a dialog with the server, and authenticates the current user on the
336 * server. This does not need any extra privileges. The basic connection to
337 * the server must already have been established before this is called. If
338 * login fails, this function prints an error and never returns. This
339 * initializes the random state, and leaves it initialized (it will also have
340 * references from the packet module).
344 ssh_login(int host_key_valid, RSA * host_key, const char *host,
345 struct sockaddr * hostaddr, uid_t original_real_uid);
347 /*------------ Definitions for various authentication methods. -------*/
350 * Tries to authenticate the user using the .rhosts file. Returns true if
351 * authentication succeeds. If ignore_rhosts is non-zero, this will not
352 * consider .rhosts and .shosts (/etc/hosts.equiv will still be used).
354 int auth_rhosts(struct passwd * pw, const char *client_user);
357 * Tries to authenticate the user using the .rhosts file and the host using
358 * its host key. Returns true if authentication succeeds.
361 auth_rhosts_rsa(struct passwd * pw, const char *client_user, RSA* client_host_key);
364 * Tries to authenticate the user using password. Returns true if
365 * authentication succeeds.
367 int auth_password(struct passwd * pw, const char *password);
370 * Performs the RSA authentication dialog with the client. This returns 0 if
371 * the client could not be authenticated, and 1 if authentication was
372 * successful. This may exit if there is a serious protocol violation.
374 int auth_rsa(struct passwd * pw, BIGNUM * client_n);
377 * Parses an RSA key (number of bits, e, n) from a string. Moves the pointer
378 * over the key. Skips any whitespace at the beginning and at end.
380 int auth_rsa_read_key(char **cpp, unsigned int *bitsp, BIGNUM * e, BIGNUM * n);
383 * Returns the name of the machine at the other end of the socket. The
384 * returned string should be freed by the caller.
386 char *get_remote_hostname(int socket);
389 * Return the canonical name of the host in the other side of the current
390 * connection (as returned by packet_get_connection). The host name is
391 * cached, so it is efficient to call this several times.
393 const char *get_canonical_hostname(void);
396 * Returns the remote IP address as an ascii string. The value need not be
397 * freed by the caller.
399 const char *get_remote_ipaddr(void);
401 /* Returns the port number of the peer of the socket. */
402 int get_peer_port(int sock);
404 /* Returns the port number of the remote/local host. */
405 int get_remote_port(void);
406 int get_local_port(void);
410 * Performs the RSA authentication challenge-response dialog with the client,
411 * and returns true (non-zero) if the client gave the correct answer to our
412 * challenge; returns zero if the client gives a wrong answer.
414 int auth_rsa_challenge_dialog(RSA *pk);
417 * Reads a passphrase from /dev/tty with echo turned off. Returns the
418 * passphrase (allocated with xmalloc). Exits if EOF is encountered. If
419 * from_stdin is true, the passphrase will be read from stdin instead.
421 char *read_passphrase(char *prompt, int from_stdin);
424 /*------------ Definitions for logging. -----------------------*/
426 /* Supported syslog facilities and levels. */
428 SYSLOG_FACILITY_DAEMON,
429 SYSLOG_FACILITY_USER,
430 SYSLOG_FACILITY_AUTH,
432 SYSLOG_FACILITY_AUTHPRIV,
434 SYSLOG_FACILITY_LOCAL0,
435 SYSLOG_FACILITY_LOCAL1,
436 SYSLOG_FACILITY_LOCAL2,
437 SYSLOG_FACILITY_LOCAL3,
438 SYSLOG_FACILITY_LOCAL4,
439 SYSLOG_FACILITY_LOCAL5,
440 SYSLOG_FACILITY_LOCAL6,
441 SYSLOG_FACILITY_LOCAL7
449 SYSLOG_LEVEL_VERBOSE,
454 /* Initializes logging. */
455 void log_init(char *av0, LogLevel level, SyslogFacility facility, int on_stderr);
457 /* Logging implementation, depending on server or client */
458 void do_log(LogLevel level, const char *fmt, va_list args);
460 /* name to facility/level */
461 SyslogFacility log_facility_number(char *name);
462 LogLevel log_level_number(char *name);
464 /* Output a message to syslog or stderr */
465 void fatal(const char *fmt,...) __attribute__((format(printf, 1, 2)));
466 void error(const char *fmt,...) __attribute__((format(printf, 1, 2)));
467 void log(const char *fmt,...) __attribute__((format(printf, 1, 2)));
468 void verbose(const char *fmt,...) __attribute__((format(printf, 1, 2)));
469 void debug(const char *fmt,...) __attribute__((format(printf, 1, 2)));
470 void debug2(const char *fmt,...) __attribute__((format(printf, 1, 2)));
471 void debug3(const char *fmt,...) __attribute__((format(printf, 1, 2)));
473 /* same as fatal() but w/o logging */
474 void fatal_cleanup(void);
477 * Registers a cleanup function to be called by fatal()/fatal_cleanup()
478 * before exiting. It is permissible to call fatal_remove_cleanup for the
479 * function itself from the function.
481 void fatal_add_cleanup(void (*proc) (void *context), void *context);
483 /* Removes a cleanup function to be called at fatal(). */
484 void fatal_remove_cleanup(void (*proc) (void *context), void *context);
489 * Expands tildes in the file name. Returns data allocated by xmalloc.
490 * Warning: this calls getpw*.
492 char *tilde_expand_filename(const char *filename, uid_t my_uid);
494 /* remove newline at end of string */
497 /* return next token in configuration line */
498 char *strdelim(char **s);
500 /* set filedescriptor to non-blocking */
501 void set_nonblock(int fd);
504 * Performs the interactive session. This handles data transmission between
505 * the client and the program. Note that the notion of stdin, stdout, and
506 * stderr in this function is sort of reversed: this function writes to stdin
507 * (of the child program), and reads from stdout and stderr (of the child
510 void server_loop(pid_t pid, int fdin, int fdout, int fderr);
511 void server_loop2(void);
513 /* Client side main loop for the interactive session. */
514 int client_loop(int have_pty, int escape_char, int id);
516 /* Linked list of custom environment strings (see auth-rsa.c). */
518 struct envstring *next;
523 * Ensure all of data on socket comes through. f==read || f==write
525 ssize_t atomicio(ssize_t (*f)(), int fd, void *s, size_t n);
530 * Performs Kerberos v4 mutual authentication with the client. This returns 0
531 * if the client could not be authenticated, and 1 if authentication was
532 * successful. This may exit if there is a serious protocol violation.
534 int auth_krb4(const char *server_user, KTEXT auth, char **client);
535 int krb4_init(uid_t uid);
536 void krb4_cleanup_proc(void *ignore);
537 int auth_krb4_password(struct passwd * pw, const char *password);
542 /* Accept passed Kerberos v4 ticket-granting ticket and AFS tokens. */
543 int auth_kerberos_tgt(struct passwd * pw, const char *string);
544 int auth_afs_token(struct passwd * pw, const char *token_string);
546 int creds_to_radix(CREDENTIALS * creds, unsigned char *buf, size_t buflen);
547 int radix_to_creds(const char *buf, CREDENTIALS * creds);
554 char *skey_fake_keyinfo(char *username);
555 int auth_skey_password(struct passwd * pw, const char *password);
558 /* AF_UNSPEC or AF_INET or AF_INET6 */