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"
79 #define PIDDIR "/var/run"
83 * System-wide file containing host keys of known hosts. This file should be
86 #define SSH_SYSTEM_HOSTFILE ETCDIR "/ssh_known_hosts"
89 * Of these, ssh_host_key must be readable only by root, whereas ssh_config
90 * should be world-readable.
92 #define HOST_KEY_FILE ETCDIR "/ssh_host_key"
93 #define SERVER_CONFIG_FILE ETCDIR "/sshd_config"
94 #define HOST_CONFIG_FILE ETCDIR "/ssh_config"
95 #define DSA_KEY_FILE ETCDIR "/ssh_dsa_key"
98 #define SSH_PROGRAM "/usr/bin/ssh"
99 #endif /* SSH_PROGRAM */
101 #ifndef LOGIN_PROGRAM
102 #define LOGIN_PROGRAM "/usr/bin/login"
103 #endif /* LOGIN_PROGRAM */
105 #ifndef ASKPASS_PROGRAM
106 #define ASKPASS_PROGRAM "/usr/lib/ssh/ssh-askpass"
107 #endif /* ASKPASS_PROGRAM */
110 * The process id of the daemon listening for connections is saved here to
111 * make it easier to kill the correct daemon when necessary.
113 #define SSH_DAEMON_PID_FILE PIDDIR "/sshd.pid"
116 * The directory in user\'s home directory in which the files reside. The
117 * directory should be world-readable (though not all files are).
119 #define SSH_USER_DIR ".ssh"
122 * Per-user file containing host keys of known hosts. This file need not be
123 * readable by anyone except the user him/herself, though this does not
124 * contain anything particularly secret.
126 #define SSH_USER_HOSTFILE "~/.ssh/known_hosts"
129 * Name of the default file containing client-side authentication key. This
130 * file should only be readable by the user him/herself.
132 #define SSH_CLIENT_IDENTITY ".ssh/identity"
135 * Configuration file in user\'s home directory. This file need not be
136 * readable by anyone but the user him/herself, but does not contain anything
137 * particularly secret. If the user\'s home directory resides on an NFS
138 * volume where root is mapped to nobody, this may need to be world-readable.
140 #define SSH_USER_CONFFILE ".ssh/config"
143 * File containing a list of those rsa keys that permit logging in as this
144 * user. This file need not be readable by anyone but the user him/herself,
145 * but does not contain anything particularly secret. If the user\'s home
146 * directory resides on an NFS volume where root is mapped to nobody, this
147 * may need to be world-readable. (This file is read by the daemon which is
150 #define SSH_USER_PERMITTED_KEYS ".ssh/authorized_keys"
153 * Per-user and system-wide ssh "rc" files. These files are executed with
154 * /bin/sh before starting the shell or command if they exist. They will be
155 * passed "proto cookie" as arguments if X11 forwarding with spoofing is in
156 * use. xauth will be run if neither of these exists.
158 #define SSH_USER_RC ".ssh/rc"
159 #define SSH_SYSTEM_RC ETCDIR "/sshrc"
162 * Ssh-only version of /etc/hosts.equiv. Additionally, the daemon may use
163 * ~/.rhosts and /etc/hosts.equiv if rhosts authentication is enabled.
165 #define SSH_HOSTS_EQUIV ETCDIR "/shosts.equiv"
168 * Name of the environment variable containing the pathname of the
169 * authentication socket.
171 #define SSH_AUTHSOCKET_ENV_NAME "SSH_AUTH_SOCK"
174 * Name of the environment variable containing the pathname of the
175 * authentication socket.
177 #define SSH_AGENTPID_ENV_NAME "SSH_AGENT_PID"
180 * Default path to ssh-askpass used by ssh-add,
181 * environment variable for overwriting the default location
183 #ifndef SSH_ASKPASS_DEFAULT
184 # define SSH_ASKPASS_DEFAULT "/usr/X11R6/bin/ssh-askpass"
186 #define SSH_ASKPASS_ENV "SSH_ASKPASS"
189 * Force host key length and server key length to differ by at least this
190 * many bits. This is to make double encryption with rsaref work.
192 #define SSH_KEY_BITS_RESERVED 128
195 * Length of the session key in bytes. (Specified as 256 bits in the
198 #define SSH_SESSION_KEY_LENGTH 32
200 /* Name of Kerberos service for SSH to use. */
201 #define KRB4_SERVICE_NAME "rcmd"
204 * Authentication methods. New types can be added, but old types should not
205 * be removed for compatibility. The maximum allowed value is 31.
207 #define SSH_AUTH_RHOSTS 1
208 #define SSH_AUTH_RSA 2
209 #define SSH_AUTH_PASSWORD 3
210 #define SSH_AUTH_RHOSTS_RSA 4
211 #define SSH_AUTH_TIS 5
212 #define SSH_AUTH_KERBEROS 6
213 #define SSH_PASS_KERBEROS_TGT 7
214 /* 8 to 15 are reserved */
215 #define SSH_PASS_AFS_TOKEN 21
217 /* Protocol flags. These are bit masks. */
218 #define SSH_PROTOFLAG_SCREEN_NUMBER 1 /* X11 forwarding includes screen */
219 #define SSH_PROTOFLAG_HOST_IN_FWD_OPEN 2 /* forwarding opens contain host */
222 * Definition of message types. New values can be added, but old values
223 * should not be removed or without careful consideration of the consequences
224 * for compatibility. The maximum value is 254; value 255 is reserved for
227 /* Message name */ /* msg code */ /* arguments */
228 #define SSH_MSG_NONE 0 /* no message */
229 #define SSH_MSG_DISCONNECT 1 /* cause (string) */
230 #define SSH_SMSG_PUBLIC_KEY 2 /* ck,msk,srvk,hostk */
231 #define SSH_CMSG_SESSION_KEY 3 /* key (BIGNUM) */
232 #define SSH_CMSG_USER 4 /* user (string) */
233 #define SSH_CMSG_AUTH_RHOSTS 5 /* user (string) */
234 #define SSH_CMSG_AUTH_RSA 6 /* modulus (BIGNUM) */
235 #define SSH_SMSG_AUTH_RSA_CHALLENGE 7 /* int (BIGNUM) */
236 #define SSH_CMSG_AUTH_RSA_RESPONSE 8 /* int (BIGNUM) */
237 #define SSH_CMSG_AUTH_PASSWORD 9 /* pass (string) */
238 #define SSH_CMSG_REQUEST_PTY 10 /* TERM, tty modes */
239 #define SSH_CMSG_WINDOW_SIZE 11 /* row,col,xpix,ypix */
240 #define SSH_CMSG_EXEC_SHELL 12 /* */
241 #define SSH_CMSG_EXEC_CMD 13 /* cmd (string) */
242 #define SSH_SMSG_SUCCESS 14 /* */
243 #define SSH_SMSG_FAILURE 15 /* */
244 #define SSH_CMSG_STDIN_DATA 16 /* data (string) */
245 #define SSH_SMSG_STDOUT_DATA 17 /* data (string) */
246 #define SSH_SMSG_STDERR_DATA 18 /* data (string) */
247 #define SSH_CMSG_EOF 19 /* */
248 #define SSH_SMSG_EXITSTATUS 20 /* status (int) */
249 #define SSH_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* channel (int) */
250 #define SSH_MSG_CHANNEL_OPEN_FAILURE 22 /* channel (int) */
251 #define SSH_MSG_CHANNEL_DATA 23 /* ch,data (int,str) */
252 #define SSH_MSG_CHANNEL_CLOSE 24 /* channel (int) */
253 #define SSH_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* channel (int) */
254 /* SSH_CMSG_X11_REQUEST_FORWARDING 26 OBSOLETE */
255 #define SSH_SMSG_X11_OPEN 27 /* channel (int) */
256 #define SSH_CMSG_PORT_FORWARD_REQUEST 28 /* p,host,hp (i,s,i) */
257 #define SSH_MSG_PORT_OPEN 29 /* ch,h,p (i,s,i) */
258 #define SSH_CMSG_AGENT_REQUEST_FORWARDING 30 /* */
259 #define SSH_SMSG_AGENT_OPEN 31 /* port (int) */
260 #define SSH_MSG_IGNORE 32 /* string */
261 #define SSH_CMSG_EXIT_CONFIRMATION 33 /* */
262 #define SSH_CMSG_X11_REQUEST_FORWARDING 34 /* proto,data (s,s) */
263 #define SSH_CMSG_AUTH_RHOSTS_RSA 35 /* user,mod (s,mpi) */
264 #define SSH_MSG_DEBUG 36 /* string */
265 #define SSH_CMSG_REQUEST_COMPRESSION 37 /* level 1-9 (int) */
266 #define SSH_CMSG_MAX_PACKET_SIZE 38 /* size 4k-1024k (int) */
267 #define SSH_CMSG_AUTH_TIS 39 /* we use this for s/key */
268 #define SSH_SMSG_AUTH_TIS_CHALLENGE 40 /* challenge (string) */
269 #define SSH_CMSG_AUTH_TIS_RESPONSE 41 /* response (string) */
270 #define SSH_CMSG_AUTH_KERBEROS 42 /* (KTEXT) */
271 #define SSH_SMSG_AUTH_KERBEROS_RESPONSE 43 /* (KTEXT) */
272 #define SSH_CMSG_HAVE_KERBEROS_TGT 44 /* credentials (s) */
273 #define SSH_CMSG_HAVE_AFS_TOKEN 65 /* token (s) */
275 /*------------ definitions for login.c -------------*/
278 * Returns the time when the user last logged in. Returns 0 if the
279 * information is not available. This must be called before record_login.
280 * The host from which the user logged in is stored in buf.
283 get_last_login_time(uid_t uid, const char *logname,
284 char *buf, unsigned int bufsize);
287 * Records that the user has logged in. This does many things normally done
291 record_login(pid_t pid, const char *ttyname, const char *user, uid_t uid,
292 const char *host, struct sockaddr *addr);
295 * Records that the user has logged out. This does many thigs normally done
296 * by login(1) or init.
298 void record_logout(pid_t pid, const char *ttyname);
300 /*------------ definitions for sshconnect.c ----------*/
303 * Opens a TCP/IP connection to the remote server on the given host. If port
304 * is 0, the default port will be used. If anonymous is zero, a privileged
305 * port will be allocated to make the connection. This requires super-user
306 * privileges if anonymous is false. Connection_attempts specifies the
307 * maximum number of tries, one per second. This returns true on success,
308 * and zero on failure. If the connection is successful, this calls
309 * packet_set_connection for the connection.
312 ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
313 u_short port, int connection_attempts,
314 int anonymous, uid_t original_real_uid,
315 const char *proxy_command);
318 * Starts a dialog with the server, and authenticates the current user on the
319 * server. This does not need any extra privileges. The basic connection to
320 * the server must already have been established before this is called. If
321 * login fails, this function prints an error and never returns. This
322 * initializes the random state, and leaves it initialized (it will also have
323 * references from the packet module).
327 ssh_login(int host_key_valid, RSA * host_key, const char *host,
328 struct sockaddr * hostaddr, uid_t original_real_uid);
330 /*------------ Definitions for various authentication methods. -------*/
333 * Tries to authenticate the user using the .rhosts file. Returns true if
334 * authentication succeeds. If ignore_rhosts is non-zero, this will not
335 * consider .rhosts and .shosts (/etc/hosts.equiv will still be used).
337 int auth_rhosts(struct passwd * pw, const char *client_user);
340 * Tries to authenticate the user using the .rhosts file and the host using
341 * its host key. Returns true if authentication succeeds.
344 auth_rhosts_rsa(struct passwd * pw, const char *client_user, RSA* client_host_key);
347 * Tries to authenticate the user using password. Returns true if
348 * authentication succeeds.
350 int auth_password(struct passwd * pw, const char *password);
353 * Performs the RSA authentication dialog with the client. This returns 0 if
354 * the client could not be authenticated, and 1 if authentication was
355 * successful. This may exit if there is a serious protocol violation.
357 int auth_rsa(struct passwd * pw, BIGNUM * client_n);
360 * Parses an RSA key (number of bits, e, n) from a string. Moves the pointer
361 * over the key. Skips any whitespace at the beginning and at end.
363 int auth_rsa_read_key(char **cpp, unsigned int *bitsp, BIGNUM * e, BIGNUM * n);
366 * Returns the name of the machine at the other end of the socket. The
367 * returned string should be freed by the caller.
369 char *get_remote_hostname(int socket);
372 * Return the canonical name of the host in the other side of the current
373 * connection (as returned by packet_get_connection). The host name is
374 * cached, so it is efficient to call this several times.
376 const char *get_canonical_hostname(void);
379 * Returns the remote IP address as an ascii string. The value need not be
380 * freed by the caller.
382 const char *get_remote_ipaddr(void);
384 /* Returns the port number of the peer of the socket. */
385 int get_peer_port(int sock);
387 /* Returns the port number of the remote/local host. */
388 int get_remote_port(void);
389 int get_local_port(void);
393 * Performs the RSA authentication challenge-response dialog with the client,
394 * and returns true (non-zero) if the client gave the correct answer to our
395 * challenge; returns zero if the client gives a wrong answer.
397 int auth_rsa_challenge_dialog(RSA *pk);
400 * Reads a passphrase from /dev/tty with echo turned off. Returns the
401 * passphrase (allocated with xmalloc). Exits if EOF is encountered. If
402 * from_stdin is true, the passphrase will be read from stdin instead.
404 char *read_passphrase(const char *prompt, int from_stdin);
407 * Saves the authentication (private) key in a file, encrypting it with
408 * passphrase. The identification of the file (lowest 64 bits of n) will
409 * precede the key to provide identification of the key without needing a
413 save_private_key(const char *filename, const char *passphrase,
414 RSA * private_key, const char *comment);
417 * Loads the public part of the key file (public key and comment). Returns 0
418 * if an error occurred; zero if the public key was successfully read. The
419 * comment of the key is returned in comment_return if it is non-NULL; the
420 * caller must free the value with xfree.
423 load_public_key(const char *filename, RSA * pub,
424 char **comment_return);
427 * Loads the private key from the file. Returns 0 if an error is encountered
428 * (file does not exist or is not readable, or passphrase is bad). This
429 * initializes the private key. The comment of the key is returned in
430 * comment_return if it is non-NULL; the caller must free the value with
434 load_private_key(const char *filename, const char *passphrase,
435 RSA * private_key, char **comment_return);
437 /*------------ Definitions for logging. -----------------------*/
439 /* Supported syslog facilities and levels. */
441 SYSLOG_FACILITY_DAEMON,
442 SYSLOG_FACILITY_USER,
443 SYSLOG_FACILITY_AUTH,
444 SYSLOG_FACILITY_LOCAL0,
445 SYSLOG_FACILITY_LOCAL1,
446 SYSLOG_FACILITY_LOCAL2,
447 SYSLOG_FACILITY_LOCAL3,
448 SYSLOG_FACILITY_LOCAL4,
449 SYSLOG_FACILITY_LOCAL5,
450 SYSLOG_FACILITY_LOCAL6,
451 SYSLOG_FACILITY_LOCAL7
459 SYSLOG_LEVEL_VERBOSE,
462 /* Initializes logging. */
463 void log_init(char *av0, LogLevel level, SyslogFacility facility, int on_stderr);
465 /* Logging implementation, depending on server or client */
466 void do_log(LogLevel level, const char *fmt, va_list args);
468 /* name to facility/level */
469 SyslogFacility log_facility_number(char *name);
470 LogLevel log_level_number(char *name);
472 /* Output a message to syslog or stderr */
473 void fatal(const char *fmt,...) __attribute__((format(printf, 1, 2)));
474 void error(const char *fmt,...) __attribute__((format(printf, 1, 2)));
475 void log(const char *fmt,...) __attribute__((format(printf, 1, 2)));
476 void verbose(const char *fmt,...) __attribute__((format(printf, 1, 2)));
477 void debug(const char *fmt,...) __attribute__((format(printf, 1, 2)));
479 /* same as fatal() but w/o logging */
480 void fatal_cleanup(void);
483 * Registers a cleanup function to be called by fatal()/fatal_cleanup()
484 * before exiting. It is permissible to call fatal_remove_cleanup for the
485 * function itself from the function.
487 void fatal_add_cleanup(void (*proc) (void *context), void *context);
489 /* Removes a cleanup function to be called at fatal(). */
490 void fatal_remove_cleanup(void (*proc) (void *context), void *context);
495 * Expands tildes in the file name. Returns data allocated by xmalloc.
496 * Warning: this calls getpw*.
498 char *tilde_expand_filename(const char *filename, uid_t my_uid);
501 * Performs the interactive session. This handles data transmission between
502 * the client and the program. Note that the notion of stdin, stdout, and
503 * stderr in this function is sort of reversed: this function writes to stdin
504 * (of the child program), and reads from stdout and stderr (of the child
507 void server_loop(pid_t pid, int fdin, int fdout, int fderr);
508 void server_loop2(void);
510 /* Client side main loop for the interactive session. */
511 int client_loop(int have_pty, int escape_char);
513 /* Linked list of custom environment strings (see auth-rsa.c). */
515 struct envstring *next;
520 * Ensure all of data on socket comes through. f==read || f==write
522 ssize_t atomicio(ssize_t (*f)(), int fd, void *s, size_t n);
527 * Performs Kerberos v4 mutual authentication with the client. This returns 0
528 * if the client could not be authenticated, and 1 if authentication was
529 * successful. This may exit if there is a serious protocol violation.
531 int auth_krb4(const char *server_user, KTEXT auth, char **client);
532 int krb4_init(uid_t uid);
533 void krb4_cleanup_proc(void *ignore);
534 int auth_krb4_password(struct passwd * pw, const char *password);
539 /* Accept passed Kerberos v4 ticket-granting ticket and AFS tokens. */
540 int auth_kerberos_tgt(struct passwd * pw, const char *string);
541 int auth_afs_token(struct passwd * pw, const char *token_string);
543 int creds_to_radix(CREDENTIALS * creds, unsigned char *buf);
544 int radix_to_creds(const char *buf, CREDENTIALS * creds);
551 char *skey_fake_keyinfo(char *username);
552 int auth_skey_password(struct passwd * pw, const char *password);
555 /* AF_UNSPEC or AF_INET or AF_INET6 */
559 #include "auth-pam.h"