5 * Author: Tatu Ylonen <ylo@cs.hut.fi>
7 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
10 * Created: Fri Mar 17 17:09:37 1995 ylo
12 * Generic header file for ssh.
21 #include <netinet/in.h> /* For struct sockaddr_in */
22 #include <pwd.h> /* For struct pw */
23 #include <stdarg.h> /* For va_list */
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>
34 * The default cipher used if IDEA is not supported by the remote host. It is
35 * recommended that this be one of the mandatory ciphers (DES, 3DES), though
36 * that is not required.
38 #define SSH_FALLBACK_CIPHER SSH_CIPHER_3DES
40 /* Cipher used for encrypting authentication files. */
41 #define SSH_AUTHFILE_CIPHER SSH_CIPHER_3DES
43 /* Default port number. */
44 #define SSH_DEFAULT_PORT 22
46 /* Maximum number of TCP/IP ports forwarded per direction. */
47 #define SSH_MAX_FORWARDS_PER_DIRECTION 100
50 * Maximum number of RSA authentication identity files that can be specified
51 * in configuration files or on the command line.
53 #define SSH_MAX_IDENTITY_FILES 100
56 * Major protocol version. Different version indicates major incompatiblity
57 * that prevents communication.
59 * Minor protocol version. Different version indicates minor incompatibility
60 * that does not prevent interoperation.
62 #define PROTOCOL_MAJOR_1 1
63 #define PROTOCOL_MINOR_1 5
65 /* We support both SSH1 and SSH2 */
66 #define PROTOCOL_MAJOR_2 2
67 #define PROTOCOL_MINOR_2 0
70 * Name for the service. The port named by this service overrides the
71 * default port if present.
73 #define SSH_SERVICE_NAME "ssh"
75 #if defined(USE_PAM) && !defined(SSHD_PAM_SERVICE)
76 # define SSHD_PAM_SERVICE "sshd"
84 #define PIDDIR "/var/run"
88 * System-wide file containing host keys of known hosts. This file should be
91 #define SSH_SYSTEM_HOSTFILE ETCDIR "/ssh_known_hosts"
92 #define SSH_SYSTEM_HOSTFILE2 ETCDIR "/ssh_known_hosts2"
95 * Of these, ssh_host_key must be readable only by root, whereas ssh_config
96 * should be world-readable.
98 #define HOST_KEY_FILE ETCDIR "/ssh_host_key"
99 #define SERVER_CONFIG_FILE ETCDIR "/sshd_config"
100 #define HOST_CONFIG_FILE ETCDIR "/ssh_config"
101 #define HOST_DSA_KEY_FILE ETCDIR "/ssh_host_dsa_key"
104 #define SSH_PROGRAM "/usr/bin/ssh"
105 #endif /* SSH_PROGRAM */
107 #ifndef LOGIN_PROGRAM
108 #define LOGIN_PROGRAM "/usr/bin/login"
109 #endif /* LOGIN_PROGRAM */
111 #ifndef ASKPASS_PROGRAM
112 #define ASKPASS_PROGRAM "/usr/lib/ssh/ssh-askpass"
113 #endif /* ASKPASS_PROGRAM */
116 * The process id of the daemon listening for connections is saved here to
117 * make it easier to kill the correct daemon when necessary.
119 #define SSH_DAEMON_PID_FILE PIDDIR "/sshd.pid"
122 * The directory in user\'s home directory in which the files reside. The
123 * directory should be world-readable (though not all files are).
125 #define SSH_USER_DIR ".ssh"
128 * Relevant only when using builtin PRNG.
130 #ifndef SSH_PRNG_SEED_FILE
131 # define SSH_PRNG_SEED_FILE SSH_USER_DIR"/prng_seed"
132 #endif /* SSH_PRNG_SEED_FILE */
133 #ifndef SSH_PRNG_COMMAND_FILE
134 # define SSH_PRNG_COMMAND_FILE ETCDIR "/ssh_prng_cmds"
135 #endif /* SSH_PRNG_COMMAND_FILE */
138 * Per-user file containing host keys of known hosts. This file need not be
139 * readable by anyone except the user him/herself, though this does not
140 * contain anything particularly secret.
142 #define SSH_USER_HOSTFILE "~/.ssh/known_hosts"
143 #define SSH_USER_HOSTFILE2 "~/.ssh/known_hosts2"
146 * Name of the default file containing client-side authentication key. This
147 * file should only be readable by the user him/herself.
149 #define SSH_CLIENT_IDENTITY ".ssh/identity"
150 #define SSH_CLIENT_ID_DSA ".ssh/id_dsa"
153 * Configuration file in user\'s home directory. This file need not be
154 * readable by anyone but the user him/herself, but does not contain anything
155 * particularly secret. If the user\'s home directory resides on an NFS
156 * volume where root is mapped to nobody, this may need to be world-readable.
158 #define SSH_USER_CONFFILE ".ssh/config"
161 * File containing a list of those rsa keys that permit logging in as this
162 * user. This file need not be readable by anyone but the user him/herself,
163 * but does not contain anything particularly secret. If the user\'s home
164 * directory resides on an NFS volume where root is mapped to nobody, this
165 * may need to be world-readable. (This file is read by the daemon which is
168 #define SSH_USER_PERMITTED_KEYS ".ssh/authorized_keys"
169 #define SSH_USER_PERMITTED_KEYS2 ".ssh/authorized_keys2"
172 * Per-user and system-wide ssh "rc" files. These files are executed with
173 * /bin/sh before starting the shell or command if they exist. They will be
174 * passed "proto cookie" as arguments if X11 forwarding with spoofing is in
175 * use. xauth will be run if neither of these exists.
177 #define SSH_USER_RC ".ssh/rc"
178 #define SSH_SYSTEM_RC ETCDIR "/sshrc"
181 * Ssh-only version of /etc/hosts.equiv. Additionally, the daemon may use
182 * ~/.rhosts and /etc/hosts.equiv if rhosts authentication is enabled.
184 #define SSH_HOSTS_EQUIV ETCDIR "/shosts.equiv"
187 * Name of the environment variable containing the pathname of the
188 * authentication socket.
190 #define SSH_AUTHSOCKET_ENV_NAME "SSH_AUTH_SOCK"
193 * Name of the environment variable containing the pathname of the
194 * authentication socket.
196 #define SSH_AGENTPID_ENV_NAME "SSH_AGENT_PID"
199 * Default path to ssh-askpass used by ssh-add,
200 * environment variable for overwriting the default location
202 #ifndef SSH_ASKPASS_DEFAULT
203 # define SSH_ASKPASS_DEFAULT "/usr/X11R6/bin/ssh-askpass"
205 #define SSH_ASKPASS_ENV "SSH_ASKPASS"
208 * Force host key length and server key length to differ by at least this
209 * many bits. This is to make double encryption with rsaref work.
211 #define SSH_KEY_BITS_RESERVED 128
214 * Length of the session key in bytes. (Specified as 256 bits in the
217 #define SSH_SESSION_KEY_LENGTH 32
219 /* Name of Kerberos service for SSH to use. */
220 #define KRB4_SERVICE_NAME "rcmd"
223 * Authentication methods. New types can be added, but old types should not
224 * be removed for compatibility. The maximum allowed value is 31.
226 #define SSH_AUTH_RHOSTS 1
227 #define SSH_AUTH_RSA 2
228 #define SSH_AUTH_PASSWORD 3
229 #define SSH_AUTH_RHOSTS_RSA 4
230 #define SSH_AUTH_TIS 5
231 #define SSH_AUTH_KERBEROS 6
232 #define SSH_PASS_KERBEROS_TGT 7
233 /* 8 to 15 are reserved */
234 #define SSH_PASS_AFS_TOKEN 21
236 /* Protocol flags. These are bit masks. */
237 #define SSH_PROTOFLAG_SCREEN_NUMBER 1 /* X11 forwarding includes screen */
238 #define SSH_PROTOFLAG_HOST_IN_FWD_OPEN 2 /* forwarding opens contain host */
241 * Definition of message types. New values can be added, but old values
242 * should not be removed or without careful consideration of the consequences
243 * for compatibility. The maximum value is 254; value 255 is reserved for
246 /* Message name */ /* msg code */ /* arguments */
247 #define SSH_MSG_NONE 0 /* no message */
248 #define SSH_MSG_DISCONNECT 1 /* cause (string) */
249 #define SSH_SMSG_PUBLIC_KEY 2 /* ck,msk,srvk,hostk */
250 #define SSH_CMSG_SESSION_KEY 3 /* key (BIGNUM) */
251 #define SSH_CMSG_USER 4 /* user (string) */
252 #define SSH_CMSG_AUTH_RHOSTS 5 /* user (string) */
253 #define SSH_CMSG_AUTH_RSA 6 /* modulus (BIGNUM) */
254 #define SSH_SMSG_AUTH_RSA_CHALLENGE 7 /* int (BIGNUM) */
255 #define SSH_CMSG_AUTH_RSA_RESPONSE 8 /* int (BIGNUM) */
256 #define SSH_CMSG_AUTH_PASSWORD 9 /* pass (string) */
257 #define SSH_CMSG_REQUEST_PTY 10 /* TERM, tty modes */
258 #define SSH_CMSG_WINDOW_SIZE 11 /* row,col,xpix,ypix */
259 #define SSH_CMSG_EXEC_SHELL 12 /* */
260 #define SSH_CMSG_EXEC_CMD 13 /* cmd (string) */
261 #define SSH_SMSG_SUCCESS 14 /* */
262 #define SSH_SMSG_FAILURE 15 /* */
263 #define SSH_CMSG_STDIN_DATA 16 /* data (string) */
264 #define SSH_SMSG_STDOUT_DATA 17 /* data (string) */
265 #define SSH_SMSG_STDERR_DATA 18 /* data (string) */
266 #define SSH_CMSG_EOF 19 /* */
267 #define SSH_SMSG_EXITSTATUS 20 /* status (int) */
268 #define SSH_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* channel (int) */
269 #define SSH_MSG_CHANNEL_OPEN_FAILURE 22 /* channel (int) */
270 #define SSH_MSG_CHANNEL_DATA 23 /* ch,data (int,str) */
271 #define SSH_MSG_CHANNEL_CLOSE 24 /* channel (int) */
272 #define SSH_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* channel (int) */
273 /* SSH_CMSG_X11_REQUEST_FORWARDING 26 OBSOLETE */
274 #define SSH_SMSG_X11_OPEN 27 /* channel (int) */
275 #define SSH_CMSG_PORT_FORWARD_REQUEST 28 /* p,host,hp (i,s,i) */
276 #define SSH_MSG_PORT_OPEN 29 /* ch,h,p (i,s,i) */
277 #define SSH_CMSG_AGENT_REQUEST_FORWARDING 30 /* */
278 #define SSH_SMSG_AGENT_OPEN 31 /* port (int) */
279 #define SSH_MSG_IGNORE 32 /* string */
280 #define SSH_CMSG_EXIT_CONFIRMATION 33 /* */
281 #define SSH_CMSG_X11_REQUEST_FORWARDING 34 /* proto,data (s,s) */
282 #define SSH_CMSG_AUTH_RHOSTS_RSA 35 /* user,mod (s,mpi) */
283 #define SSH_MSG_DEBUG 36 /* string */
284 #define SSH_CMSG_REQUEST_COMPRESSION 37 /* level 1-9 (int) */
285 #define SSH_CMSG_MAX_PACKET_SIZE 38 /* size 4k-1024k (int) */
286 #define SSH_CMSG_AUTH_TIS 39 /* we use this for s/key */
287 #define SSH_SMSG_AUTH_TIS_CHALLENGE 40 /* challenge (string) */
288 #define SSH_CMSG_AUTH_TIS_RESPONSE 41 /* response (string) */
289 #define SSH_CMSG_AUTH_KERBEROS 42 /* (KTEXT) */
290 #define SSH_SMSG_AUTH_KERBEROS_RESPONSE 43 /* (KTEXT) */
291 #define SSH_CMSG_HAVE_KERBEROS_TGT 44 /* credentials (s) */
292 #define SSH_CMSG_HAVE_AFS_TOKEN 65 /* token (s) */
294 /*------------ definitions for login.c -------------*/
297 * Returns the time when the user last logged in. Returns 0 if the
298 * information is not available. This must be called before record_login.
299 * The host from which the user logged in is stored in buf.
302 get_last_login_time(uid_t uid, const char *logname,
303 char *buf, unsigned int bufsize);
306 * Records that the user has logged in. This does many things normally done
310 record_login(pid_t pid, const char *ttyname, const char *user, uid_t uid,
311 const char *host, struct sockaddr *addr);
314 * Records that the user has logged out. This does many thigs normally done
315 * by login(1) or init.
317 void record_logout(pid_t pid, const char *ttyname);
319 /*------------ definitions for sshconnect.c ----------*/
322 * Opens a TCP/IP connection to the remote server on the given host. If port
323 * is 0, the default port will be used. If anonymous is zero, a privileged
324 * port will be allocated to make the connection. This requires super-user
325 * privileges if anonymous is false. Connection_attempts specifies the
326 * maximum number of tries, one per second. This returns true on success,
327 * and zero on failure. If the connection is successful, this calls
328 * packet_set_connection for the connection.
331 ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
332 u_short port, int connection_attempts,
333 int anonymous, uid_t original_real_uid,
334 const char *proxy_command);
337 * Starts a dialog with the server, and authenticates the current user on the
338 * server. This does not need any extra privileges. The basic connection to
339 * the server must already have been established before this is called. If
340 * login fails, this function prints an error and never returns. This
341 * initializes the random state, and leaves it initialized (it will also have
342 * references from the packet module).
346 ssh_login(int host_key_valid, RSA * host_key, const char *host,
347 struct sockaddr * hostaddr, uid_t original_real_uid);
349 /*------------ Definitions for various authentication methods. -------*/
352 * Tries to authenticate the user using the .rhosts file. Returns true if
353 * authentication succeeds. If ignore_rhosts is non-zero, this will not
354 * consider .rhosts and .shosts (/etc/hosts.equiv will still be used).
356 int auth_rhosts(struct passwd * pw, const char *client_user);
359 * Tries to authenticate the user using the .rhosts file and the host using
360 * its host key. Returns true if authentication succeeds.
363 auth_rhosts_rsa(struct passwd * pw, const char *client_user, RSA* client_host_key);
366 * Tries to authenticate the user using password. Returns true if
367 * authentication succeeds.
369 int auth_password(struct passwd * pw, const char *password);
372 * Performs the RSA authentication dialog with the client. This returns 0 if
373 * the client could not be authenticated, and 1 if authentication was
374 * successful. This may exit if there is a serious protocol violation.
376 int auth_rsa(struct passwd * pw, BIGNUM * client_n);
379 * Parses an RSA key (number of bits, e, n) from a string. Moves the pointer
380 * over the key. Skips any whitespace at the beginning and at end.
382 int auth_rsa_read_key(char **cpp, unsigned int *bitsp, BIGNUM * e, BIGNUM * n);
385 * Returns the name of the machine at the other end of the socket. The
386 * returned string should be freed by the caller.
388 char *get_remote_hostname(int socket);
391 * Return the canonical name of the host in the other side of the current
392 * connection (as returned by packet_get_connection). The host name is
393 * cached, so it is efficient to call this several times.
395 const char *get_canonical_hostname(void);
398 * Returns the remote IP address as an ascii string. The value need not be
399 * freed by the caller.
401 const char *get_remote_ipaddr(void);
403 /* Returns the port number of the peer of the socket. */
404 int get_peer_port(int sock);
406 /* Returns the port number of the remote/local host. */
407 int get_remote_port(void);
408 int get_local_port(void);
412 * Performs the RSA authentication challenge-response dialog with the client,
413 * and returns true (non-zero) if the client gave the correct answer to our
414 * challenge; returns zero if the client gives a wrong answer.
416 int auth_rsa_challenge_dialog(RSA *pk);
419 * Reads a passphrase from /dev/tty with echo turned off. Returns the
420 * passphrase (allocated with xmalloc). Exits if EOF is encountered. If
421 * from_stdin is true, the passphrase will be read from stdin instead.
423 char *read_passphrase(const char *prompt, int from_stdin);
426 /*------------ Definitions for logging. -----------------------*/
428 /* Supported syslog facilities and levels. */
430 SYSLOG_FACILITY_DAEMON,
431 SYSLOG_FACILITY_USER,
432 SYSLOG_FACILITY_AUTH,
433 SYSLOG_FACILITY_LOCAL0,
434 SYSLOG_FACILITY_LOCAL1,
435 SYSLOG_FACILITY_LOCAL2,
436 SYSLOG_FACILITY_LOCAL3,
437 SYSLOG_FACILITY_LOCAL4,
438 SYSLOG_FACILITY_LOCAL5,
439 SYSLOG_FACILITY_LOCAL6,
440 SYSLOG_FACILITY_LOCAL7
448 SYSLOG_LEVEL_VERBOSE,
451 /* Initializes logging. */
452 void log_init(char *av0, LogLevel level, SyslogFacility facility, int on_stderr);
454 /* Logging implementation, depending on server or client */
455 void do_log(LogLevel level, const char *fmt, va_list args);
457 /* name to facility/level */
458 SyslogFacility log_facility_number(char *name);
459 LogLevel log_level_number(char *name);
461 /* Output a message to syslog or stderr */
462 void fatal(const char *fmt,...) __attribute__((format(printf, 1, 2)));
463 void error(const char *fmt,...) __attribute__((format(printf, 1, 2)));
464 void log(const char *fmt,...) __attribute__((format(printf, 1, 2)));
465 void verbose(const char *fmt,...) __attribute__((format(printf, 1, 2)));
466 void debug(const char *fmt,...) __attribute__((format(printf, 1, 2)));
468 /* same as fatal() but w/o logging */
469 void fatal_cleanup(void);
472 * Registers a cleanup function to be called by fatal()/fatal_cleanup()
473 * before exiting. It is permissible to call fatal_remove_cleanup for the
474 * function itself from the function.
476 void fatal_add_cleanup(void (*proc) (void *context), void *context);
478 /* Removes a cleanup function to be called at fatal(). */
479 void fatal_remove_cleanup(void (*proc) (void *context), void *context);
484 * Expands tildes in the file name. Returns data allocated by xmalloc.
485 * Warning: this calls getpw*.
487 char *tilde_expand_filename(const char *filename, uid_t my_uid);
490 * Performs the interactive session. This handles data transmission between
491 * the client and the program. Note that the notion of stdin, stdout, and
492 * stderr in this function is sort of reversed: this function writes to stdin
493 * (of the child program), and reads from stdout and stderr (of the child
496 void server_loop(pid_t pid, int fdin, int fdout, int fderr);
497 void server_loop2(void);
499 /* Client side main loop for the interactive session. */
500 int client_loop(int have_pty, int escape_char);
502 /* Linked list of custom environment strings (see auth-rsa.c). */
504 struct envstring *next;
509 * Ensure all of data on socket comes through. f==read || f==write
511 ssize_t atomicio(ssize_t (*f)(), int fd, void *s, size_t n);
516 * Performs Kerberos v4 mutual authentication with the client. This returns 0
517 * if the client could not be authenticated, and 1 if authentication was
518 * successful. This may exit if there is a serious protocol violation.
520 int auth_krb4(const char *server_user, KTEXT auth, char **client);
521 int krb4_init(uid_t uid);
522 void krb4_cleanup_proc(void *ignore);
523 int auth_krb4_password(struct passwd * pw, const char *password);
528 /* Accept passed Kerberos v4 ticket-granting ticket and AFS tokens. */
529 int auth_kerberos_tgt(struct passwd * pw, const char *string);
530 int auth_afs_token(struct passwd * pw, const char *token_string);
532 int creds_to_radix(CREDENTIALS * creds, unsigned char *buf, size_t buflen);
533 int radix_to_creds(const char *buf, CREDENTIALS * creds);
540 char *skey_fake_keyinfo(char *username);
541 int auth_skey_password(struct passwd * pw, const char *password);
544 /* AF_UNSPEC or AF_INET or AF_INET6 */
548 #include "auth-pam.h"