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>
33 * The default cipher used if IDEA is not supported by the remote host. It is
34 * recommended that this be one of the mandatory ciphers (DES, 3DES), though
35 * that is not required.
37 #define SSH_FALLBACK_CIPHER SSH_CIPHER_3DES
39 /* Cipher used for encrypting authentication files. */
40 #define SSH_AUTHFILE_CIPHER SSH_CIPHER_3DES
42 /* Default port number. */
43 #define SSH_DEFAULT_PORT 22
45 /* Maximum number of TCP/IP ports forwarded per direction. */
46 #define SSH_MAX_FORWARDS_PER_DIRECTION 100
49 * Maximum number of RSA authentication identity files that can be specified
50 * in configuration files or on the command line.
52 #define SSH_MAX_IDENTITY_FILES 100
55 * Major protocol version. Different version indicates major incompatiblity
56 * that prevents communication.
58 * Minor protocol version. Different version indicates minor incompatibility
59 * that does not prevent interoperation.
61 #define PROTOCOL_MAJOR_1 1
62 #define PROTOCOL_MINOR_1 5
64 /* We support both SSH1 and SSH2 */
65 #define PROTOCOL_MAJOR_2 2
66 #define PROTOCOL_MINOR_2 0
69 * Name for the service. The port named by this service overrides the
70 * default port if present.
72 #define SSH_SERVICE_NAME "ssh"
74 #if defined(USE_PAM) && !defined(SSHD_PAM_SERVICE)
75 # define SSHD_PAM_SERVICE "sshd"
83 #define PIDDIR "/var/run"
87 * System-wide file containing host keys of known hosts. This file should be
90 #define SSH_SYSTEM_HOSTFILE ETCDIR "/ssh_known_hosts"
91 #define SSH_SYSTEM_HOSTFILE2 ETCDIR "/ssh_known_hosts2"
94 * Of these, ssh_host_key must be readable only by root, whereas ssh_config
95 * should be world-readable.
97 #define HOST_KEY_FILE ETCDIR "/ssh_host_key"
98 #define SERVER_CONFIG_FILE ETCDIR "/sshd_config"
99 #define HOST_CONFIG_FILE ETCDIR "/ssh_config"
100 #define DSA_KEY_FILE ETCDIR "/ssh_host_dsa_key"
103 #define SSH_PROGRAM "/usr/bin/ssh"
104 #endif /* SSH_PROGRAM */
106 #ifndef LOGIN_PROGRAM
107 #define LOGIN_PROGRAM "/usr/bin/login"
108 #endif /* LOGIN_PROGRAM */
110 #ifndef ASKPASS_PROGRAM
111 #define ASKPASS_PROGRAM "/usr/lib/ssh/ssh-askpass"
112 #endif /* ASKPASS_PROGRAM */
115 * The process id of the daemon listening for connections is saved here to
116 * make it easier to kill the correct daemon when necessary.
118 #define SSH_DAEMON_PID_FILE PIDDIR "/sshd.pid"
121 * The directory in user\'s home directory in which the files reside. The
122 * directory should be world-readable (though not all files are).
124 #define SSH_USER_DIR ".ssh"
127 * Per-user file containing host keys of known hosts. This file need not be
128 * readable by anyone except the user him/herself, though this does not
129 * contain anything particularly secret.
131 #define SSH_USER_HOSTFILE "~/.ssh/known_hosts"
132 #define SSH_USER_HOSTFILE2 "~/.ssh/known_hosts2"
135 * Name of the default file containing client-side authentication key. This
136 * file should only be readable by the user him/herself.
138 #define SSH_CLIENT_IDENTITY ".ssh/identity"
141 * Configuration file in user\'s home directory. This file need not be
142 * readable by anyone but the user him/herself, but does not contain anything
143 * particularly secret. If the user\'s home directory resides on an NFS
144 * volume where root is mapped to nobody, this may need to be world-readable.
146 #define SSH_USER_CONFFILE ".ssh/config"
149 * File containing a list of those rsa keys that permit logging in as this
150 * user. This file need not be readable by anyone but the user him/herself,
151 * but does not contain anything particularly secret. If the user\'s home
152 * directory resides on an NFS volume where root is mapped to nobody, this
153 * may need to be world-readable. (This file is read by the daemon which is
156 #define SSH_USER_PERMITTED_KEYS ".ssh/authorized_keys"
157 #define SSH_USER_PERMITTED_KEYS2 ".ssh/authorized_keys2"
160 * Per-user and system-wide ssh "rc" files. These files are executed with
161 * /bin/sh before starting the shell or command if they exist. They will be
162 * passed "proto cookie" as arguments if X11 forwarding with spoofing is in
163 * use. xauth will be run if neither of these exists.
165 #define SSH_USER_RC ".ssh/rc"
166 #define SSH_SYSTEM_RC ETCDIR "/sshrc"
169 * Ssh-only version of /etc/hosts.equiv. Additionally, the daemon may use
170 * ~/.rhosts and /etc/hosts.equiv if rhosts authentication is enabled.
172 #define SSH_HOSTS_EQUIV ETCDIR "/shosts.equiv"
175 * Name of the environment variable containing the pathname of the
176 * authentication socket.
178 #define SSH_AUTHSOCKET_ENV_NAME "SSH_AUTH_SOCK"
181 * Name of the environment variable containing the pathname of the
182 * authentication socket.
184 #define SSH_AGENTPID_ENV_NAME "SSH_AGENT_PID"
187 * Default path to ssh-askpass used by ssh-add,
188 * environment variable for overwriting the default location
190 #ifndef SSH_ASKPASS_DEFAULT
191 # define SSH_ASKPASS_DEFAULT "/usr/X11R6/bin/ssh-askpass"
193 #define SSH_ASKPASS_ENV "SSH_ASKPASS"
196 * Force host key length and server key length to differ by at least this
197 * many bits. This is to make double encryption with rsaref work.
199 #define SSH_KEY_BITS_RESERVED 128
202 * Length of the session key in bytes. (Specified as 256 bits in the
205 #define SSH_SESSION_KEY_LENGTH 32
207 /* Name of Kerberos service for SSH to use. */
208 #define KRB4_SERVICE_NAME "rcmd"
211 * Authentication methods. New types can be added, but old types should not
212 * be removed for compatibility. The maximum allowed value is 31.
214 #define SSH_AUTH_RHOSTS 1
215 #define SSH_AUTH_RSA 2
216 #define SSH_AUTH_PASSWORD 3
217 #define SSH_AUTH_RHOSTS_RSA 4
218 #define SSH_AUTH_TIS 5
219 #define SSH_AUTH_KERBEROS 6
220 #define SSH_PASS_KERBEROS_TGT 7
221 /* 8 to 15 are reserved */
222 #define SSH_PASS_AFS_TOKEN 21
224 /* Protocol flags. These are bit masks. */
225 #define SSH_PROTOFLAG_SCREEN_NUMBER 1 /* X11 forwarding includes screen */
226 #define SSH_PROTOFLAG_HOST_IN_FWD_OPEN 2 /* forwarding opens contain host */
229 * Definition of message types. New values can be added, but old values
230 * should not be removed or without careful consideration of the consequences
231 * for compatibility. The maximum value is 254; value 255 is reserved for
234 /* Message name */ /* msg code */ /* arguments */
235 #define SSH_MSG_NONE 0 /* no message */
236 #define SSH_MSG_DISCONNECT 1 /* cause (string) */
237 #define SSH_SMSG_PUBLIC_KEY 2 /* ck,msk,srvk,hostk */
238 #define SSH_CMSG_SESSION_KEY 3 /* key (BIGNUM) */
239 #define SSH_CMSG_USER 4 /* user (string) */
240 #define SSH_CMSG_AUTH_RHOSTS 5 /* user (string) */
241 #define SSH_CMSG_AUTH_RSA 6 /* modulus (BIGNUM) */
242 #define SSH_SMSG_AUTH_RSA_CHALLENGE 7 /* int (BIGNUM) */
243 #define SSH_CMSG_AUTH_RSA_RESPONSE 8 /* int (BIGNUM) */
244 #define SSH_CMSG_AUTH_PASSWORD 9 /* pass (string) */
245 #define SSH_CMSG_REQUEST_PTY 10 /* TERM, tty modes */
246 #define SSH_CMSG_WINDOW_SIZE 11 /* row,col,xpix,ypix */
247 #define SSH_CMSG_EXEC_SHELL 12 /* */
248 #define SSH_CMSG_EXEC_CMD 13 /* cmd (string) */
249 #define SSH_SMSG_SUCCESS 14 /* */
250 #define SSH_SMSG_FAILURE 15 /* */
251 #define SSH_CMSG_STDIN_DATA 16 /* data (string) */
252 #define SSH_SMSG_STDOUT_DATA 17 /* data (string) */
253 #define SSH_SMSG_STDERR_DATA 18 /* data (string) */
254 #define SSH_CMSG_EOF 19 /* */
255 #define SSH_SMSG_EXITSTATUS 20 /* status (int) */
256 #define SSH_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* channel (int) */
257 #define SSH_MSG_CHANNEL_OPEN_FAILURE 22 /* channel (int) */
258 #define SSH_MSG_CHANNEL_DATA 23 /* ch,data (int,str) */
259 #define SSH_MSG_CHANNEL_CLOSE 24 /* channel (int) */
260 #define SSH_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* channel (int) */
261 /* SSH_CMSG_X11_REQUEST_FORWARDING 26 OBSOLETE */
262 #define SSH_SMSG_X11_OPEN 27 /* channel (int) */
263 #define SSH_CMSG_PORT_FORWARD_REQUEST 28 /* p,host,hp (i,s,i) */
264 #define SSH_MSG_PORT_OPEN 29 /* ch,h,p (i,s,i) */
265 #define SSH_CMSG_AGENT_REQUEST_FORWARDING 30 /* */
266 #define SSH_SMSG_AGENT_OPEN 31 /* port (int) */
267 #define SSH_MSG_IGNORE 32 /* string */
268 #define SSH_CMSG_EXIT_CONFIRMATION 33 /* */
269 #define SSH_CMSG_X11_REQUEST_FORWARDING 34 /* proto,data (s,s) */
270 #define SSH_CMSG_AUTH_RHOSTS_RSA 35 /* user,mod (s,mpi) */
271 #define SSH_MSG_DEBUG 36 /* string */
272 #define SSH_CMSG_REQUEST_COMPRESSION 37 /* level 1-9 (int) */
273 #define SSH_CMSG_MAX_PACKET_SIZE 38 /* size 4k-1024k (int) */
274 #define SSH_CMSG_AUTH_TIS 39 /* we use this for s/key */
275 #define SSH_SMSG_AUTH_TIS_CHALLENGE 40 /* challenge (string) */
276 #define SSH_CMSG_AUTH_TIS_RESPONSE 41 /* response (string) */
277 #define SSH_CMSG_AUTH_KERBEROS 42 /* (KTEXT) */
278 #define SSH_SMSG_AUTH_KERBEROS_RESPONSE 43 /* (KTEXT) */
279 #define SSH_CMSG_HAVE_KERBEROS_TGT 44 /* credentials (s) */
280 #define SSH_CMSG_HAVE_AFS_TOKEN 65 /* token (s) */
282 /*------------ definitions for login.c -------------*/
285 * Returns the time when the user last logged in. Returns 0 if the
286 * information is not available. This must be called before record_login.
287 * The host from which the user logged in is stored in buf.
290 get_last_login_time(uid_t uid, const char *logname,
291 char *buf, unsigned int bufsize);
294 * Records that the user has logged in. This does many things normally done
298 record_login(pid_t pid, const char *ttyname, const char *user, uid_t uid,
299 const char *host, struct sockaddr *addr);
302 * Records that the user has logged out. This does many thigs normally done
303 * by login(1) or init.
305 void record_logout(pid_t pid, const char *ttyname);
307 /*------------ definitions for sshconnect.c ----------*/
310 * Opens a TCP/IP connection to the remote server on the given host. If port
311 * is 0, the default port will be used. If anonymous is zero, a privileged
312 * port will be allocated to make the connection. This requires super-user
313 * privileges if anonymous is false. Connection_attempts specifies the
314 * maximum number of tries, one per second. This returns true on success,
315 * and zero on failure. If the connection is successful, this calls
316 * packet_set_connection for the connection.
319 ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
320 u_short port, int connection_attempts,
321 int anonymous, uid_t original_real_uid,
322 const char *proxy_command);
325 * Starts a dialog with the server, and authenticates the current user on the
326 * server. This does not need any extra privileges. The basic connection to
327 * the server must already have been established before this is called. If
328 * login fails, this function prints an error and never returns. This
329 * initializes the random state, and leaves it initialized (it will also have
330 * references from the packet module).
334 ssh_login(int host_key_valid, RSA * host_key, const char *host,
335 struct sockaddr * hostaddr, uid_t original_real_uid);
337 /*------------ Definitions for various authentication methods. -------*/
340 * Tries to authenticate the user using the .rhosts file. Returns true if
341 * authentication succeeds. If ignore_rhosts is non-zero, this will not
342 * consider .rhosts and .shosts (/etc/hosts.equiv will still be used).
344 int auth_rhosts(struct passwd * pw, const char *client_user);
347 * Tries to authenticate the user using the .rhosts file and the host using
348 * its host key. Returns true if authentication succeeds.
351 auth_rhosts_rsa(struct passwd * pw, const char *client_user, RSA* client_host_key);
354 * Tries to authenticate the user using password. Returns true if
355 * authentication succeeds.
357 int auth_password(struct passwd * pw, const char *password);
360 * Performs the RSA authentication dialog with the client. This returns 0 if
361 * the client could not be authenticated, and 1 if authentication was
362 * successful. This may exit if there is a serious protocol violation.
364 int auth_rsa(struct passwd * pw, BIGNUM * client_n);
367 * Parses an RSA key (number of bits, e, n) from a string. Moves the pointer
368 * over the key. Skips any whitespace at the beginning and at end.
370 int auth_rsa_read_key(char **cpp, unsigned int *bitsp, BIGNUM * e, BIGNUM * n);
373 * Returns the name of the machine at the other end of the socket. The
374 * returned string should be freed by the caller.
376 char *get_remote_hostname(int socket);
379 * Return the canonical name of the host in the other side of the current
380 * connection (as returned by packet_get_connection). The host name is
381 * cached, so it is efficient to call this several times.
383 const char *get_canonical_hostname(void);
386 * Returns the remote IP address as an ascii string. The value need not be
387 * freed by the caller.
389 const char *get_remote_ipaddr(void);
391 /* Returns the port number of the peer of the socket. */
392 int get_peer_port(int sock);
394 /* Returns the port number of the remote/local host. */
395 int get_remote_port(void);
396 int get_local_port(void);
400 * Performs the RSA authentication challenge-response dialog with the client,
401 * and returns true (non-zero) if the client gave the correct answer to our
402 * challenge; returns zero if the client gives a wrong answer.
404 int auth_rsa_challenge_dialog(RSA *pk);
407 * Reads a passphrase from /dev/tty with echo turned off. Returns the
408 * passphrase (allocated with xmalloc). Exits if EOF is encountered. If
409 * from_stdin is true, the passphrase will be read from stdin instead.
411 char *read_passphrase(const char *prompt, int from_stdin);
414 /*------------ Definitions for logging. -----------------------*/
416 /* Supported syslog facilities and levels. */
418 SYSLOG_FACILITY_DAEMON,
419 SYSLOG_FACILITY_USER,
420 SYSLOG_FACILITY_AUTH,
421 SYSLOG_FACILITY_LOCAL0,
422 SYSLOG_FACILITY_LOCAL1,
423 SYSLOG_FACILITY_LOCAL2,
424 SYSLOG_FACILITY_LOCAL3,
425 SYSLOG_FACILITY_LOCAL4,
426 SYSLOG_FACILITY_LOCAL5,
427 SYSLOG_FACILITY_LOCAL6,
428 SYSLOG_FACILITY_LOCAL7
436 SYSLOG_LEVEL_VERBOSE,
439 /* Initializes logging. */
440 void log_init(char *av0, LogLevel level, SyslogFacility facility, int on_stderr);
442 /* Logging implementation, depending on server or client */
443 void do_log(LogLevel level, const char *fmt, va_list args);
445 /* name to facility/level */
446 SyslogFacility log_facility_number(char *name);
447 LogLevel log_level_number(char *name);
449 /* Output a message to syslog or stderr */
450 void fatal(const char *fmt,...) __attribute__((format(printf, 1, 2)));
451 void error(const char *fmt,...) __attribute__((format(printf, 1, 2)));
452 void log(const char *fmt,...) __attribute__((format(printf, 1, 2)));
453 void verbose(const char *fmt,...) __attribute__((format(printf, 1, 2)));
454 void debug(const char *fmt,...) __attribute__((format(printf, 1, 2)));
456 /* same as fatal() but w/o logging */
457 void fatal_cleanup(void);
460 * Registers a cleanup function to be called by fatal()/fatal_cleanup()
461 * before exiting. It is permissible to call fatal_remove_cleanup for the
462 * function itself from the function.
464 void fatal_add_cleanup(void (*proc) (void *context), void *context);
466 /* Removes a cleanup function to be called at fatal(). */
467 void fatal_remove_cleanup(void (*proc) (void *context), void *context);
472 * Expands tildes in the file name. Returns data allocated by xmalloc.
473 * Warning: this calls getpw*.
475 char *tilde_expand_filename(const char *filename, uid_t my_uid);
478 * Performs the interactive session. This handles data transmission between
479 * the client and the program. Note that the notion of stdin, stdout, and
480 * stderr in this function is sort of reversed: this function writes to stdin
481 * (of the child program), and reads from stdout and stderr (of the child
484 void server_loop(pid_t pid, int fdin, int fdout, int fderr);
485 void server_loop2(void);
487 /* Client side main loop for the interactive session. */
488 int client_loop(int have_pty, int escape_char);
490 /* Linked list of custom environment strings (see auth-rsa.c). */
492 struct envstring *next;
497 * Ensure all of data on socket comes through. f==read || f==write
499 ssize_t atomicio(ssize_t (*f)(), int fd, void *s, size_t n);
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.
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);
516 /* Accept passed Kerberos v4 ticket-granting ticket and AFS tokens. */
517 int auth_kerberos_tgt(struct passwd * pw, const char *string);
518 int auth_afs_token(struct passwd * pw, const char *token_string);
520 int creds_to_radix(CREDENTIALS * creds, unsigned char *buf);
521 int radix_to_creds(const char *buf, CREDENTIALS * creds);
528 char *skey_fake_keyinfo(char *username);
529 int auth_skey_password(struct passwd * pw, const char *password);
532 /* AF_UNSPEC or AF_INET or AF_INET6 */
536 #include "auth-pam.h"