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openssh/ssh.h

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/*
*
* ssh.h
*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
*
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
*
* Created: Fri Mar 17 17:09:37 1995 ylo
*
* Generic header file for ssh.
*
*/
/* RCSID("$Id: ssh.h,v 1.30 2000/04/12 08:45:07 damien Exp $"); */
#ifndef SSH_H
#define SSH_H
#include <netinet/in.h> /* For struct sockaddr_in */
#include <pwd.h> /* For struct pw */
#include <stdarg.h> /* For va_list */
#include <sys/socket.h> /* For struct sockaddr_storage */
#include "fake-socket.h" /* For struct sockaddr_storage */
#ifdef HAVE_SYS_SELECT_H
# include <sys/select.h>
#endif
#include "rsa.h"
#include "cipher.h"
/*
* The default cipher used if IDEA is not supported by the remote host. It is
* recommended that this be one of the mandatory ciphers (DES, 3DES), though
* that is not required.
*/
#define SSH_FALLBACK_CIPHER SSH_CIPHER_3DES
/* Cipher used for encrypting authentication files. */
#define SSH_AUTHFILE_CIPHER SSH_CIPHER_3DES
/* Default port number. */
#define SSH_DEFAULT_PORT 22
/* Maximum number of TCP/IP ports forwarded per direction. */
#define SSH_MAX_FORWARDS_PER_DIRECTION 100
/*
* Maximum number of RSA authentication identity files that can be specified
* in configuration files or on the command line.
*/
#define SSH_MAX_IDENTITY_FILES 100
/*
* Major protocol version. Different version indicates major incompatiblity
* that prevents communication.
*/
#define PROTOCOL_MAJOR 1
/*
* Minor protocol version. Different version indicates minor incompatibility
* that does not prevent interoperation.
*/
#define PROTOCOL_MINOR 5
/*
* Name for the service. The port named by this service overrides the
* default port if present.
*/
#define SSH_SERVICE_NAME "ssh"
#ifndef ETCDIR
#define ETCDIR "/etc"
#endif /* ETCDIR */
#ifndef PIDDIR
#define PIDDIR "/var/run"
#endif /* PIDDIR */
/*
* System-wide file containing host keys of known hosts. This file should be
* world-readable.
*/
#define SSH_SYSTEM_HOSTFILE ETCDIR "/ssh_known_hosts"
/*
* Of these, ssh_host_key must be readable only by root, whereas ssh_config
* should be world-readable.
*/
#define HOST_KEY_FILE ETCDIR "/ssh_host_key"
#define SERVER_CONFIG_FILE ETCDIR "/sshd_config"
#define HOST_CONFIG_FILE ETCDIR "/ssh_config"
#define DSA_KEY_FILE ETCDIR "/ssh_dsa_key"
#ifndef SSH_PROGRAM
#define SSH_PROGRAM "/usr/bin/ssh"
#endif /* SSH_PROGRAM */
#ifndef LOGIN_PROGRAM
#define LOGIN_PROGRAM "/usr/bin/login"
#endif /* LOGIN_PROGRAM */
#ifndef ASKPASS_PROGRAM
#define ASKPASS_PROGRAM "/usr/lib/ssh/ssh-askpass"
#endif /* ASKPASS_PROGRAM */
/*
* The process id of the daemon listening for connections is saved here to
* make it easier to kill the correct daemon when necessary.
*/
#define SSH_DAEMON_PID_FILE PIDDIR "/sshd.pid"
/*
* The directory in user\'s home directory in which the files reside. The
* directory should be world-readable (though not all files are).
*/
#define SSH_USER_DIR ".ssh"
/*
* Per-user file containing host keys of known hosts. This file need not be
* readable by anyone except the user him/herself, though this does not
* contain anything particularly secret.
*/
#define SSH_USER_HOSTFILE "~/.ssh/known_hosts"
/*
* Name of the default file containing client-side authentication key. This
* file should only be readable by the user him/herself.
*/
#define SSH_CLIENT_IDENTITY ".ssh/identity"
/*
* Configuration file in user\'s home directory. This file need not be
* readable by anyone but the user him/herself, but does not contain anything
* particularly secret. If the user\'s home directory resides on an NFS
* volume where root is mapped to nobody, this may need to be world-readable.
*/
#define SSH_USER_CONFFILE ".ssh/config"
/*
* File containing a list of those rsa keys that permit logging in as this
* user. This file need not be readable by anyone but the user him/herself,
* but does not contain anything particularly secret. If the user\'s home
* directory resides on an NFS volume where root is mapped to nobody, this
* may need to be world-readable. (This file is read by the daemon which is
* running as root.)
*/
#define SSH_USER_PERMITTED_KEYS ".ssh/authorized_keys"
/*
* Per-user and system-wide ssh "rc" files. These files are executed with
* /bin/sh before starting the shell or command if they exist. They will be
* passed "proto cookie" as arguments if X11 forwarding with spoofing is in
* use. xauth will be run if neither of these exists.
*/
#define SSH_USER_RC ".ssh/rc"
#define SSH_SYSTEM_RC ETCDIR "/sshrc"
/*
* Ssh-only version of /etc/hosts.equiv. Additionally, the daemon may use
* ~/.rhosts and /etc/hosts.equiv if rhosts authentication is enabled.
*/
#define SSH_HOSTS_EQUIV ETCDIR "/shosts.equiv"
/*
* Name of the environment variable containing the pathname of the
* authentication socket.
*/
#define SSH_AUTHSOCKET_ENV_NAME "SSH_AUTH_SOCK"
/*
* Name of the environment variable containing the pathname of the
* authentication socket.
*/
#define SSH_AGENTPID_ENV_NAME "SSH_AGENT_PID"
/*
* Default path to ssh-askpass used by ssh-add,
* environment variable for overwriting the default location
*/
#ifndef SSH_ASKPASS_DEFAULT
# define SSH_ASKPASS_DEFAULT "/usr/X11R6/bin/ssh-askpass"
#endif
#define SSH_ASKPASS_ENV "SSH_ASKPASS"
/*
* Force host key length and server key length to differ by at least this
* many bits. This is to make double encryption with rsaref work.
*/
#define SSH_KEY_BITS_RESERVED 128
/*
* Length of the session key in bytes. (Specified as 256 bits in the
* protocol.)
*/
#define SSH_SESSION_KEY_LENGTH 32
/* Name of Kerberos service for SSH to use. */
#define KRB4_SERVICE_NAME "rcmd"
/*
* Authentication methods. New types can be added, but old types should not
* be removed for compatibility. The maximum allowed value is 31.
*/
#define SSH_AUTH_RHOSTS 1
#define SSH_AUTH_RSA 2
#define SSH_AUTH_PASSWORD 3
#define SSH_AUTH_RHOSTS_RSA 4
#define SSH_AUTH_TIS 5
#define SSH_AUTH_KERBEROS 6
#define SSH_PASS_KERBEROS_TGT 7
/* 8 to 15 are reserved */
#define SSH_PASS_AFS_TOKEN 21
/* Protocol flags. These are bit masks. */
#define SSH_PROTOFLAG_SCREEN_NUMBER 1 /* X11 forwarding includes screen */
#define SSH_PROTOFLAG_HOST_IN_FWD_OPEN 2 /* forwarding opens contain host */
/*
* Definition of message types. New values can be added, but old values
* should not be removed or without careful consideration of the consequences
* for compatibility. The maximum value is 254; value 255 is reserved for
* future extension.
*/
/* Message name */ /* msg code */ /* arguments */
#define SSH_MSG_NONE 0 /* no message */
#define SSH_MSG_DISCONNECT 1 /* cause (string) */
#define SSH_SMSG_PUBLIC_KEY 2 /* ck,msk,srvk,hostk */
#define SSH_CMSG_SESSION_KEY 3 /* key (BIGNUM) */
#define SSH_CMSG_USER 4 /* user (string) */
#define SSH_CMSG_AUTH_RHOSTS 5 /* user (string) */
#define SSH_CMSG_AUTH_RSA 6 /* modulus (BIGNUM) */
#define SSH_SMSG_AUTH_RSA_CHALLENGE 7 /* int (BIGNUM) */
#define SSH_CMSG_AUTH_RSA_RESPONSE 8 /* int (BIGNUM) */
#define SSH_CMSG_AUTH_PASSWORD 9 /* pass (string) */
#define SSH_CMSG_REQUEST_PTY 10 /* TERM, tty modes */
#define SSH_CMSG_WINDOW_SIZE 11 /* row,col,xpix,ypix */
#define SSH_CMSG_EXEC_SHELL 12 /* */
#define SSH_CMSG_EXEC_CMD 13 /* cmd (string) */
#define SSH_SMSG_SUCCESS 14 /* */
#define SSH_SMSG_FAILURE 15 /* */
#define SSH_CMSG_STDIN_DATA 16 /* data (string) */
#define SSH_SMSG_STDOUT_DATA 17 /* data (string) */
#define SSH_SMSG_STDERR_DATA 18 /* data (string) */
#define SSH_CMSG_EOF 19 /* */
#define SSH_SMSG_EXITSTATUS 20 /* status (int) */
#define SSH_MSG_CHANNEL_OPEN_CONFIRMATION 21 /* channel (int) */
#define SSH_MSG_CHANNEL_OPEN_FAILURE 22 /* channel (int) */
#define SSH_MSG_CHANNEL_DATA 23 /* ch,data (int,str) */
#define SSH_MSG_CHANNEL_CLOSE 24 /* channel (int) */
#define SSH_MSG_CHANNEL_CLOSE_CONFIRMATION 25 /* channel (int) */
/* SSH_CMSG_X11_REQUEST_FORWARDING 26 OBSOLETE */
#define SSH_SMSG_X11_OPEN 27 /* channel (int) */
#define SSH_CMSG_PORT_FORWARD_REQUEST 28 /* p,host,hp (i,s,i) */
#define SSH_MSG_PORT_OPEN 29 /* ch,h,p (i,s,i) */
#define SSH_CMSG_AGENT_REQUEST_FORWARDING 30 /* */
#define SSH_SMSG_AGENT_OPEN 31 /* port (int) */
#define SSH_MSG_IGNORE 32 /* string */
#define SSH_CMSG_EXIT_CONFIRMATION 33 /* */
#define SSH_CMSG_X11_REQUEST_FORWARDING 34 /* proto,data (s,s) */
#define SSH_CMSG_AUTH_RHOSTS_RSA 35 /* user,mod (s,mpi) */
#define SSH_MSG_DEBUG 36 /* string */
#define SSH_CMSG_REQUEST_COMPRESSION 37 /* level 1-9 (int) */
#define SSH_CMSG_MAX_PACKET_SIZE 38 /* size 4k-1024k (int) */
#define SSH_CMSG_AUTH_TIS 39 /* we use this for s/key */
#define SSH_SMSG_AUTH_TIS_CHALLENGE 40 /* challenge (string) */
#define SSH_CMSG_AUTH_TIS_RESPONSE 41 /* response (string) */
#define SSH_CMSG_AUTH_KERBEROS 42 /* (KTEXT) */
#define SSH_SMSG_AUTH_KERBEROS_RESPONSE 43 /* (KTEXT) */
#define SSH_CMSG_HAVE_KERBEROS_TGT 44 /* credentials (s) */
#define SSH_CMSG_HAVE_AFS_TOKEN 65 /* token (s) */
/*------------ definitions for login.c -------------*/
/*
* Returns the time when the user last logged in. Returns 0 if the
* information is not available. This must be called before record_login.
* The host from which the user logged in is stored in buf.
*/
unsigned long
get_last_login_time(uid_t uid, const char *logname,
char *buf, unsigned int bufsize);
/*
* Records that the user has logged in. This does many things normally done
* by login(1).
*/
void
record_login(int pid, const char *ttyname, const char *user, uid_t uid,
const char *host, struct sockaddr *addr);
/*
* Records that the user has logged out. This does many thigs normally done
* by login(1) or init.
*/
void record_logout(int pid, const char *ttyname);
/*------------ definitions for sshconnect.c ----------*/
/*
* Opens a TCP/IP connection to the remote server on the given host. If port
* is 0, the default port will be used. If anonymous is zero, a privileged
* port will be allocated to make the connection. This requires super-user
* privileges if anonymous is false. Connection_attempts specifies the
* maximum number of tries, one per second. This returns true on success,
* and zero on failure. If the connection is successful, this calls
* packet_set_connection for the connection.
*/
int
ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
u_short port, int connection_attempts,
int anonymous, uid_t original_real_uid,
const char *proxy_command);
/*
* Starts a dialog with the server, and authenticates the current user on the
* server. This does not need any extra privileges. The basic connection to
* the server must already have been established before this is called. If
* login fails, this function prints an error and never returns. This
* initializes the random state, and leaves it initialized (it will also have
* references from the packet module).
*/
void
ssh_login(int host_key_valid, RSA * host_key, const char *host,
struct sockaddr * hostaddr, uid_t original_real_uid);
/*------------ Definitions for various authentication methods. -------*/
/*
* Tries to authenticate the user using the .rhosts file. Returns true if
* authentication succeeds. If ignore_rhosts is non-zero, this will not
* consider .rhosts and .shosts (/etc/hosts.equiv will still be used).
*/
int auth_rhosts(struct passwd * pw, const char *client_user);
/*
* Tries to authenticate the user using the .rhosts file and the host using
* its host key. Returns true if authentication succeeds.
*/
int
auth_rhosts_rsa(struct passwd * pw, const char *client_user, RSA* client_host_key);
/*
* Tries to authenticate the user using password. Returns true if
* authentication succeeds.
*/
int auth_password(struct passwd * pw, const char *password);
/*
* Performs the RSA authentication dialog with the client. This returns 0 if
* the client could not be authenticated, and 1 if authentication was
* successful. This may exit if there is a serious protocol violation.
*/
int auth_rsa(struct passwd * pw, BIGNUM * client_n);
/*
* Parses an RSA key (number of bits, e, n) from a string. Moves the pointer
* over the key. Skips any whitespace at the beginning and at end.
*/
int auth_rsa_read_key(char **cpp, unsigned int *bitsp, BIGNUM * e, BIGNUM * n);
/*
* Returns the name of the machine at the other end of the socket. The
* returned string should be freed by the caller.
*/
char *get_remote_hostname(int socket);
/*
* Return the canonical name of the host in the other side of the current
* connection (as returned by packet_get_connection). The host name is
* cached, so it is efficient to call this several times.
*/
const char *get_canonical_hostname(void);
/*
* Returns the remote IP address as an ascii string. The value need not be
* freed by the caller.
*/
const char *get_remote_ipaddr(void);
/* Returns the port number of the peer of the socket. */
int get_peer_port(int sock);
/* Returns the port number of the remote/local host. */
int get_remote_port(void);
int get_local_port(void);
/*
* Performs the RSA authentication challenge-response dialog with the client,
* and returns true (non-zero) if the client gave the correct answer to our
* challenge; returns zero if the client gives a wrong answer.
*/
int auth_rsa_challenge_dialog(RSA *pk);
/*
* Reads a passphrase from /dev/tty with echo turned off. Returns the
* passphrase (allocated with xmalloc). Exits if EOF is encountered. If
* from_stdin is true, the passphrase will be read from stdin instead.
*/
char *read_passphrase(const char *prompt, int from_stdin);
/*
* Saves the authentication (private) key in a file, encrypting it with
* passphrase. The identification of the file (lowest 64 bits of n) will
* precede the key to provide identification of the key without needing a
* passphrase.
*/
int
save_private_key(const char *filename, const char *passphrase,
RSA * private_key, const char *comment);
/*
* Loads the public part of the key file (public key and comment). Returns 0
* if an error occurred; zero if the public key was successfully read. The
* comment of the key is returned in comment_return if it is non-NULL; the
* caller must free the value with xfree.
*/
int
load_public_key(const char *filename, RSA * pub,
char **comment_return);
/*
* Loads the private key from the file. Returns 0 if an error is encountered
* (file does not exist or is not readable, or passphrase is bad). This
* initializes the private key. The comment of the key is returned in
* comment_return if it is non-NULL; the caller must free the value with
* xfree.
*/
int
load_private_key(const char *filename, const char *passphrase,
RSA * private_key, char **comment_return);
/*------------ Definitions for logging. -----------------------*/
/* Supported syslog facilities and levels. */
typedef enum {
SYSLOG_FACILITY_DAEMON,
SYSLOG_FACILITY_USER,
SYSLOG_FACILITY_AUTH,
SYSLOG_FACILITY_LOCAL0,
SYSLOG_FACILITY_LOCAL1,
SYSLOG_FACILITY_LOCAL2,
SYSLOG_FACILITY_LOCAL3,
SYSLOG_FACILITY_LOCAL4,
SYSLOG_FACILITY_LOCAL5,
SYSLOG_FACILITY_LOCAL6,
SYSLOG_FACILITY_LOCAL7
} SyslogFacility;
typedef enum {
SYSLOG_LEVEL_QUIET,
SYSLOG_LEVEL_FATAL,
SYSLOG_LEVEL_ERROR,
SYSLOG_LEVEL_INFO,
SYSLOG_LEVEL_VERBOSE,
SYSLOG_LEVEL_DEBUG
} LogLevel;
/* Initializes logging. */
void log_init(char *av0, LogLevel level, SyslogFacility facility, int on_stderr);
/* Logging implementation, depending on server or client */
void do_log(LogLevel level, const char *fmt, va_list args);
/* name to facility/level */
SyslogFacility log_facility_number(char *name);
LogLevel log_level_number(char *name);
/* Output a message to syslog or stderr */
void fatal(const char *fmt,...) __attribute__((format(printf, 1, 2)));
void error(const char *fmt,...) __attribute__((format(printf, 1, 2)));
void log(const char *fmt,...) __attribute__((format(printf, 1, 2)));
void verbose(const char *fmt,...) __attribute__((format(printf, 1, 2)));
void debug(const char *fmt,...) __attribute__((format(printf, 1, 2)));
/* same as fatal() but w/o logging */
void fatal_cleanup(void);
/*
* Registers a cleanup function to be called by fatal()/fatal_cleanup()
* before exiting. It is permissible to call fatal_remove_cleanup for the
* function itself from the function.
*/
void fatal_add_cleanup(void (*proc) (void *context), void *context);
/* Removes a cleanup function to be called at fatal(). */
void fatal_remove_cleanup(void (*proc) (void *context), void *context);
/* ---- misc */
/*
* Expands tildes in the file name. Returns data allocated by xmalloc.
* Warning: this calls getpw*.
*/
char *tilde_expand_filename(const char *filename, uid_t my_uid);
/*
* Performs the interactive session. This handles data transmission between
* the client and the program. Note that the notion of stdin, stdout, and
* stderr in this function is sort of reversed: this function writes to stdin
* (of the child program), and reads from stdout and stderr (of the child
* program).
*/
void server_loop(int pid, int fdin, int fdout, int fderr);
void server_loop2(void);
/* Client side main loop for the interactive session. */
int client_loop(int have_pty, int escape_char);
/* Linked list of custom environment strings (see auth-rsa.c). */
struct envstring {
struct envstring *next;
char *s;
};
/*
* Ensure all of data on socket comes through. f==read || f==write
*/
ssize_t atomicio(ssize_t (*f)(), int fd, void *s, size_t n);
#ifdef KRB4
#include <krb.h>
/*
* Performs Kerberos v4 mutual authentication with the client. This returns 0
* if the client could not be authenticated, and 1 if authentication was
* successful. This may exit if there is a serious protocol violation.
*/
int auth_krb4(const char *server_user, KTEXT auth, char **client);
int krb4_init(uid_t uid);
void krb4_cleanup_proc(void *ignore);
int auth_krb4_password(struct passwd * pw, const char *password);
#ifdef AFS
#include <kafs.h>
/* Accept passed Kerberos v4 ticket-granting ticket and AFS tokens. */
int auth_kerberos_tgt(struct passwd * pw, const char *string);
int auth_afs_token(struct passwd * pw, const char *token_string);
int creds_to_radix(CREDENTIALS * creds, unsigned char *buf);
int radix_to_creds(const char *buf, CREDENTIALS * creds);
#endif /* AFS */
#endif /* KRB4 */
#ifdef SKEY
#include <skey.h>
char *skey_fake_keyinfo(char *username);
int auth_skey_password(struct passwd * pw, const char *password);
#endif /* SKEY */
/* AF_UNSPEC or AF_INET or AF_INET6 */
extern int IPv4or6;
#ifdef USE_PAM
#include "auth-pam.h"
#endif /* USE_PAM */
#endif /* SSH_H */
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