mirror of git://anongit.mindrot.org/openssh.git
2730 lines
77 KiB
C
2730 lines
77 KiB
C
/*
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* Author: Tatu Ylonen <ylo@cs.hut.fi>
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* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
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* All rights reserved
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* Created: Fri Mar 17 17:09:28 1995 ylo
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* This program is the ssh daemon. It listens for connections from clients, and
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* performs authentication, executes use commands or shell, and forwards
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* information to/from the application to the user client over an encrypted
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* connection. This can also handle forwarding of X11, TCP/IP, and authentication
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* agent connections.
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*/
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#include "includes.h"
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RCSID("$Id: sshd.c,v 1.48 1999/12/28 23:25:41 damien Exp $");
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#ifdef HAVE_POLL_H
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# include <poll.h>
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#else /* HAVE_POLL_H */
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# ifdef HAVE_SYS_POLL_H
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# include <sys/poll.h>
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# endif /* HAVE_SYS_POLL_H */
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#endif /* HAVE_POLL_H */
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#include "xmalloc.h"
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#include "rsa.h"
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#include "ssh.h"
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#include "pty.h"
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#include "packet.h"
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#include "buffer.h"
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#include "cipher.h"
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#include "mpaux.h"
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#include "servconf.h"
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#include "uidswap.h"
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#include "compat.h"
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#ifdef LIBWRAP
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#include <tcpd.h>
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#include <syslog.h>
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int allow_severity = LOG_INFO;
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int deny_severity = LOG_WARNING;
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#endif /* LIBWRAP */
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#ifndef O_NOCTTY
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#define O_NOCTTY 0
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#endif
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/* Local Xauthority file. */
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static char *xauthfile = NULL;
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/* Server configuration options. */
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ServerOptions options;
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/* Name of the server configuration file. */
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char *config_file_name = SERVER_CONFIG_FILE;
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/*
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* Debug mode flag. This can be set on the command line. If debug
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* mode is enabled, extra debugging output will be sent to the system
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* log, the daemon will not go to background, and will exit after processing
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* the first connection.
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*/
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int debug_flag = 0;
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/* Flag indicating that the daemon is being started from inetd. */
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int inetd_flag = 0;
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/* debug goes to stderr unless inetd_flag is set */
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int log_stderr = 0;
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/* argv[0] without path. */
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char *av0;
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/* Saved arguments to main(). */
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char **saved_argv;
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/*
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* This is set to the socket that the server is listening; this is used in
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* the SIGHUP signal handler.
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*/
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int listen_sock;
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/*
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* the client's version string, passed by sshd2 in compat mode. if != NULL,
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* sshd will skip the version-number exchange
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*/
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char *client_version_string = NULL;
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/* Flags set in auth-rsa from authorized_keys flags. These are set in auth-rsa.c. */
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int no_port_forwarding_flag = 0;
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int no_agent_forwarding_flag = 0;
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int no_x11_forwarding_flag = 0;
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int no_pty_flag = 0;
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/* RSA authentication "command=" option. */
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char *forced_command = NULL;
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/* RSA authentication "environment=" options. */
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struct envstring *custom_environment = NULL;
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/* Session id for the current session. */
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unsigned char session_id[16];
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/*
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* Any really sensitive data in the application is contained in this
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* structure. The idea is that this structure could be locked into memory so
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* that the pages do not get written into swap. However, there are some
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* problems. The private key contains BIGNUMs, and we do not (in principle)
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* have access to the internals of them, and locking just the structure is
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* not very useful. Currently, memory locking is not implemented.
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*/
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struct {
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RSA *private_key; /* Private part of server key. */
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RSA *host_key; /* Private part of host key. */
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} sensitive_data;
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/*
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* Flag indicating whether the current session key has been used. This flag
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* is set whenever the key is used, and cleared when the key is regenerated.
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*/
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int key_used = 0;
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/* This is set to true when SIGHUP is received. */
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int received_sighup = 0;
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/* Public side of the server key. This value is regenerated regularly with
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the private key. */
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RSA *public_key;
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/* Prototypes for various functions defined later in this file. */
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void do_connection();
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void do_authentication(char *user);
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void do_authloop(struct passwd * pw);
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void do_fake_authloop(char *user);
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void do_authenticated(struct passwd * pw);
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void do_exec_pty(const char *command, int ptyfd, int ttyfd,
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const char *ttyname, struct passwd * pw, const char *term,
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const char *display, const char *auth_proto,
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const char *auth_data);
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void do_exec_no_pty(const char *command, struct passwd * pw,
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const char *display, const char *auth_proto,
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const char *auth_data);
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void do_child(const char *command, struct passwd * pw, const char *term,
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const char *display, const char *auth_proto,
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const char *auth_data, const char *ttyname);
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#ifdef USE_PAM
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static int pamconv(int num_msg, const struct pam_message **msg,
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struct pam_response **resp, void *appdata_ptr);
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int do_pam_auth(const char *user, const char *password);
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void do_pam_account(char *username, char *remote_user);
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void do_pam_session(char *username, char *ttyname);
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void do_pam_setcred();
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void pam_cleanup_proc(void *context);
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static struct pam_conv conv = {
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pamconv,
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NULL
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};
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struct pam_handle_t *pamh = NULL;
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const char *pampasswd = NULL;
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char *pamconv_msg = NULL;
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static int pamconv(int num_msg, const struct pam_message **msg,
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struct pam_response **resp, void *appdata_ptr)
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{
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struct pam_response *reply;
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int count;
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size_t msg_len;
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char *p;
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/* PAM will free this later */
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reply = malloc(num_msg * sizeof(*reply));
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if (reply == NULL)
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return PAM_CONV_ERR;
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for(count = 0; count < num_msg; count++) {
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switch (msg[count]->msg_style) {
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case PAM_PROMPT_ECHO_OFF:
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if (pampasswd == NULL) {
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free(reply);
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return PAM_CONV_ERR;
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}
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reply[count].resp_retcode = PAM_SUCCESS;
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reply[count].resp = xstrdup(pampasswd);
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break;
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case PAM_TEXT_INFO:
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reply[count].resp_retcode = PAM_SUCCESS;
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reply[count].resp = xstrdup("");
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if (msg[count]->msg == NULL)
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break;
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debug("Adding PAM message: %s", msg[count]->msg);
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msg_len = strlen(msg[count]->msg);
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if (pamconv_msg) {
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size_t n = strlen(pamconv_msg);
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pamconv_msg = xrealloc(pamconv_msg, n + msg_len + 2);
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p = pamconv_msg + n;
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} else {
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pamconv_msg = p = xmalloc(msg_len + 2);
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}
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memcpy(p, msg[count]->msg, msg_len);
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p[msg_len] = '\n';
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p[msg_len + 1] = '\0';
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break;
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case PAM_PROMPT_ECHO_ON:
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case PAM_ERROR_MSG:
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default:
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free(reply);
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return PAM_CONV_ERR;
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}
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}
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*resp = reply;
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return PAM_SUCCESS;
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}
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void pam_cleanup_proc(void *context)
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{
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int pam_retval;
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if (pamh != NULL)
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{
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pam_retval = pam_close_session((pam_handle_t *)pamh, 0);
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if (pam_retval != PAM_SUCCESS) {
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log("Cannot close PAM session: %.200s",
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PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
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}
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pam_retval = pam_setcred((pam_handle_t *)pamh, PAM_DELETE_CRED);
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if (pam_retval != PAM_SUCCESS) {
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log("Cannot delete credentials: %.200s",
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PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
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}
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pam_retval = pam_end((pam_handle_t *)pamh, pam_retval);
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if (pam_retval != PAM_SUCCESS) {
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log("Cannot release PAM authentication: %.200s",
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PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
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}
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}
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}
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int do_pam_auth(const char *user, const char *password)
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{
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int pam_retval;
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if ((options.permit_empty_passwd == 0) && (password[0] == '\0'))
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return 0;
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pampasswd = password;
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pam_retval = pam_authenticate((pam_handle_t *)pamh, 0);
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if (pam_retval == PAM_SUCCESS) {
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debug("PAM Password authentication accepted for user \"%.100s\"", user);
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return 1;
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} else {
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debug("PAM Password authentication for \"%.100s\" failed: %s",
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user, PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
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return 0;
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}
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}
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void do_pam_account(char *username, char *remote_user)
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{
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int pam_retval;
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debug("PAM setting rhost to \"%.200s\"", get_canonical_hostname());
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pam_retval = pam_set_item((pam_handle_t *)pamh, PAM_RHOST,
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get_canonical_hostname());
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if (pam_retval != PAM_SUCCESS) {
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log("PAM set rhost failed: %.200s", PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
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do_fake_authloop(username);
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}
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if (remote_user != NULL) {
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debug("PAM setting ruser to \"%.200s\"", remote_user);
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pam_retval = pam_set_item((pam_handle_t *)pamh, PAM_RUSER, remote_user);
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if (pam_retval != PAM_SUCCESS) {
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log("PAM set ruser failed: %.200s", PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
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do_fake_authloop(username);
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}
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}
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pam_retval = pam_acct_mgmt((pam_handle_t *)pamh, 0);
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if (pam_retval != PAM_SUCCESS) {
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log("PAM rejected by account configuration: %.200s", PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
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do_fake_authloop(username);
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}
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}
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void do_pam_session(char *username, char *ttyname)
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{
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int pam_retval;
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if (ttyname != NULL) {
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debug("PAM setting tty to \"%.200s\"", ttyname);
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pam_retval = pam_set_item((pam_handle_t *)pamh, PAM_TTY, ttyname);
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if (pam_retval != PAM_SUCCESS)
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fatal("PAM set tty failed: %.200s", PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
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}
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pam_retval = pam_open_session((pam_handle_t *)pamh, 0);
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if (pam_retval != PAM_SUCCESS)
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fatal("PAM session setup failed: %.200s", PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
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}
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void do_pam_setcred()
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{
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int pam_retval;
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debug("PAM establishing creds");
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pam_retval = pam_setcred((pam_handle_t *)pamh, PAM_ESTABLISH_CRED);
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if (pam_retval != PAM_SUCCESS)
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fatal("PAM setcred failed: %.200s", PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
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}
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#endif /* USE_PAM */
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/*
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* Signal handler for SIGHUP. Sshd execs itself when it receives SIGHUP;
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* the effect is to reread the configuration file (and to regenerate
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* the server key).
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*/
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void
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sighup_handler(int sig)
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{
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received_sighup = 1;
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signal(SIGHUP, sighup_handler);
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}
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/*
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* Called from the main program after receiving SIGHUP.
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* Restarts the server.
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*/
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void
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sighup_restart()
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{
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log("Received SIGHUP; restarting.");
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close(listen_sock);
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execv(saved_argv[0], saved_argv);
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log("RESTART FAILED: av0='%s', error: %s.", av0, strerror(errno));
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exit(1);
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}
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/*
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* Generic signal handler for terminating signals in the master daemon.
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* These close the listen socket; not closing it seems to cause "Address
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* already in use" problems on some machines, which is inconvenient.
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*/
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void
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sigterm_handler(int sig)
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{
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log("Received signal %d; terminating.", sig);
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close(listen_sock);
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exit(255);
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}
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/*
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* SIGCHLD handler. This is called whenever a child dies. This will then
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* reap any zombies left by exited c.
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*/
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void
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main_sigchld_handler(int sig)
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{
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int save_errno = errno;
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int status;
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while (waitpid(-1, &status, WNOHANG) > 0)
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;
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signal(SIGCHLD, main_sigchld_handler);
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errno = save_errno;
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}
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/*
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* Signal handler for the alarm after the login grace period has expired.
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*/
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void
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grace_alarm_handler(int sig)
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{
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/* Close the connection. */
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packet_close();
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/* Log error and exit. */
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fatal("Timeout before authentication for %s.", get_remote_ipaddr());
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}
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/*
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* convert ssh auth msg type into description
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*/
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char *
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get_authname(int type)
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{
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switch (type) {
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case SSH_CMSG_AUTH_PASSWORD:
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return "password";
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case SSH_CMSG_AUTH_RSA:
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return "rsa";
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case SSH_CMSG_AUTH_RHOSTS_RSA:
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return "rhosts-rsa";
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case SSH_CMSG_AUTH_RHOSTS:
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return "rhosts";
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#ifdef KRB4
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case SSH_CMSG_AUTH_KERBEROS:
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return "kerberos";
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#endif
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#ifdef SKEY
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case SSH_CMSG_AUTH_TIS_RESPONSE:
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return "s/key";
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#endif
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}
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fatal("get_authname: unknown auth %d: internal error", type);
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return NULL;
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}
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/*
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* Signal handler for the key regeneration alarm. Note that this
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* alarm only occurs in the daemon waiting for connections, and it does not
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* do anything with the private key or random state before forking.
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* Thus there should be no concurrency control/asynchronous execution
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* problems.
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*/
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void
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key_regeneration_alarm(int sig)
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{
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int save_errno = errno;
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/* Check if we should generate a new key. */
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if (key_used) {
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/* This should really be done in the background. */
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log("Generating new %d bit RSA key.", options.server_key_bits);
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if (sensitive_data.private_key != NULL)
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RSA_free(sensitive_data.private_key);
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sensitive_data.private_key = RSA_new();
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if (public_key != NULL)
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RSA_free(public_key);
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public_key = RSA_new();
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rsa_generate_key(sensitive_data.private_key, public_key,
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options.server_key_bits);
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arc4random_stir();
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key_used = 0;
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log("RSA key generation complete.");
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}
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/* Reschedule the alarm. */
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signal(SIGALRM, key_regeneration_alarm);
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alarm(options.key_regeneration_time);
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errno = save_errno;
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}
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/*
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* Main program for the daemon.
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*/
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int
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main(int ac, char **av)
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{
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extern char *optarg;
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extern int optind;
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int opt, aux, sock_in, sock_out, newsock, i, pid, on = 1;
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int remote_major, remote_minor;
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int silentrsa = 0;
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struct pollfd fds;
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struct sockaddr_in sin;
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char buf[100]; /* Must not be larger than remote_version. */
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char remote_version[100]; /* Must be at least as big as buf. */
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const char *remote_ip;
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int remote_port;
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char *comment;
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FILE *f;
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struct linger linger;
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/* Save argv[0]. */
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saved_argv = av;
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if (strchr(av[0], '/'))
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av0 = strrchr(av[0], '/') + 1;
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else
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av0 = av[0];
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/* Initialize configuration options to their default values. */
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initialize_server_options(&options);
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/* Parse command-line arguments. */
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while ((opt = getopt(ac, av, "f:p:b:k:h:g:V:diqQ")) != EOF) {
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switch (opt) {
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case 'f':
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config_file_name = optarg;
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break;
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case 'd':
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debug_flag = 1;
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options.log_level = SYSLOG_LEVEL_DEBUG;
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break;
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case 'i':
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inetd_flag = 1;
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break;
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case 'Q':
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silentrsa = 1;
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break;
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case 'q':
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options.log_level = SYSLOG_LEVEL_QUIET;
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break;
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case 'b':
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options.server_key_bits = atoi(optarg);
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break;
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case 'p':
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options.port = atoi(optarg);
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break;
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case 'g':
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options.login_grace_time = atoi(optarg);
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break;
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case 'k':
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options.key_regeneration_time = atoi(optarg);
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break;
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case 'h':
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options.host_key_file = optarg;
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break;
|
|
case 'V':
|
|
client_version_string = optarg;
|
|
/* only makes sense with inetd_flag, i.e. no listen() */
|
|
inetd_flag = 1;
|
|
break;
|
|
case '?':
|
|
default:
|
|
fprintf(stderr, "sshd version %s\n", SSH_VERSION);
|
|
#ifdef RSAREF
|
|
fprintf(stderr, "Compiled with RSAref.\n");
|
|
#endif
|
|
fprintf(stderr, "Usage: %s [options]\n", av0);
|
|
fprintf(stderr, "Options:\n");
|
|
fprintf(stderr, " -f file Configuration file (default %s)\n", SERVER_CONFIG_FILE);
|
|
fprintf(stderr, " -d Debugging mode\n");
|
|
fprintf(stderr, " -i Started from inetd\n");
|
|
fprintf(stderr, " -q Quiet (no logging)\n");
|
|
fprintf(stderr, " -p port Listen on the specified port (default: 22)\n");
|
|
fprintf(stderr, " -k seconds Regenerate server key every this many seconds (default: 3600)\n");
|
|
fprintf(stderr, " -g seconds Grace period for authentication (default: 300)\n");
|
|
fprintf(stderr, " -b bits Size of server RSA key (default: 768 bits)\n");
|
|
fprintf(stderr, " -h file File from which to read host key (default: %s)\n",
|
|
HOST_KEY_FILE);
|
|
exit(1);
|
|
}
|
|
}
|
|
|
|
/* check if RSA support exists */
|
|
if (rsa_alive() == 0) {
|
|
if (silentrsa == 0)
|
|
printf("sshd: no RSA support in libssl and libcrypto -- exiting. See ssl(8)\n");
|
|
log("no RSA support in libssl and libcrypto -- exiting. See ssl(8)");
|
|
exit(1);
|
|
}
|
|
/* Read server configuration options from the configuration file. */
|
|
read_server_config(&options, config_file_name);
|
|
|
|
/* Fill in default values for those options not explicitly set. */
|
|
fill_default_server_options(&options);
|
|
|
|
/* Check certain values for sanity. */
|
|
if (options.server_key_bits < 512 ||
|
|
options.server_key_bits > 32768) {
|
|
fprintf(stderr, "Bad server key size.\n");
|
|
exit(1);
|
|
}
|
|
if (options.port < 1 || options.port > 65535) {
|
|
fprintf(stderr, "Bad port number.\n");
|
|
exit(1);
|
|
}
|
|
/* Check that there are no remaining arguments. */
|
|
if (optind < ac) {
|
|
fprintf(stderr, "Extra argument %s.\n", av[optind]);
|
|
exit(1);
|
|
}
|
|
/* Force logging to stderr while loading the private host key
|
|
unless started from inetd */
|
|
log_init(av0, options.log_level, options.log_facility, !inetd_flag);
|
|
|
|
debug("sshd version %.100s", SSH_VERSION);
|
|
|
|
sensitive_data.host_key = RSA_new();
|
|
errno = 0;
|
|
/* Load the host key. It must have empty passphrase. */
|
|
if (!load_private_key(options.host_key_file, "",
|
|
sensitive_data.host_key, &comment)) {
|
|
error("Could not load host key: %.200s: %.100s",
|
|
options.host_key_file, strerror(errno));
|
|
exit(1);
|
|
}
|
|
xfree(comment);
|
|
|
|
/* Initialize the log (it is reinitialized below in case we
|
|
forked). */
|
|
if (debug_flag && !inetd_flag)
|
|
log_stderr = 1;
|
|
log_init(av0, options.log_level, options.log_facility, log_stderr);
|
|
|
|
/* If not in debugging mode, and not started from inetd,
|
|
disconnect from the controlling terminal, and fork. The
|
|
original process exits. */
|
|
if (!debug_flag && !inetd_flag) {
|
|
#ifdef TIOCNOTTY
|
|
int fd;
|
|
#endif /* TIOCNOTTY */
|
|
if (daemon(0, 0) < 0)
|
|
fatal("daemon() failed: %.200s", strerror(errno));
|
|
|
|
/* Disconnect from the controlling tty. */
|
|
#ifdef TIOCNOTTY
|
|
fd = open("/dev/tty", O_RDWR | O_NOCTTY);
|
|
if (fd >= 0) {
|
|
(void) ioctl(fd, TIOCNOTTY, NULL);
|
|
close(fd);
|
|
}
|
|
#endif /* TIOCNOTTY */
|
|
}
|
|
/* Reinitialize the log (because of the fork above). */
|
|
log_init(av0, options.log_level, options.log_facility, log_stderr);
|
|
|
|
/* Check that server and host key lengths differ sufficiently.
|
|
This is necessary to make double encryption work with rsaref.
|
|
Oh, I hate software patents. I dont know if this can go? Niels */
|
|
if (options.server_key_bits >
|
|
BN_num_bits(sensitive_data.host_key->n) - SSH_KEY_BITS_RESERVED &&
|
|
options.server_key_bits <
|
|
BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) {
|
|
options.server_key_bits =
|
|
BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED;
|
|
debug("Forcing server key to %d bits to make it differ from host key.",
|
|
options.server_key_bits);
|
|
}
|
|
/* Do not display messages to stdout in RSA code. */
|
|
rsa_set_verbose(0);
|
|
|
|
/* Initialize the random number generator. */
|
|
arc4random_stir();
|
|
|
|
/* Chdir to the root directory so that the current disk can be
|
|
unmounted if desired. */
|
|
chdir("/");
|
|
|
|
/* Close connection cleanly after attack. */
|
|
cipher_attack_detected = packet_disconnect;
|
|
|
|
/* Start listening for a socket, unless started from inetd. */
|
|
if (inetd_flag) {
|
|
int s1, s2;
|
|
s1 = dup(0); /* Make sure descriptors 0, 1, and 2 are in use. */
|
|
s2 = dup(s1);
|
|
sock_in = dup(0);
|
|
sock_out = dup(1);
|
|
/* We intentionally do not close the descriptors 0, 1, and 2
|
|
as our code for setting the descriptors won\'t work
|
|
if ttyfd happens to be one of those. */
|
|
debug("inetd sockets after dupping: %d, %d", sock_in, sock_out);
|
|
|
|
public_key = RSA_new();
|
|
sensitive_data.private_key = RSA_new();
|
|
|
|
log("Generating %d bit RSA key.", options.server_key_bits);
|
|
rsa_generate_key(sensitive_data.private_key, public_key,
|
|
options.server_key_bits);
|
|
arc4random_stir();
|
|
log("RSA key generation complete.");
|
|
} else {
|
|
/* Create socket for listening. */
|
|
listen_sock = socket(AF_INET, SOCK_STREAM, 0);
|
|
if (listen_sock < 0)
|
|
fatal("socket: %.100s", strerror(errno));
|
|
|
|
/* Set socket options. We try to make the port reusable
|
|
and have it close as fast as possible without waiting
|
|
in unnecessary wait states on close. */
|
|
setsockopt(listen_sock, SOL_SOCKET, SO_REUSEADDR, (void *) &on,
|
|
sizeof(on));
|
|
linger.l_onoff = 1;
|
|
linger.l_linger = 5;
|
|
setsockopt(listen_sock, SOL_SOCKET, SO_LINGER, (void *) &linger,
|
|
sizeof(linger));
|
|
|
|
memset(&sin, 0, sizeof(sin));
|
|
sin.sin_family = AF_INET;
|
|
sin.sin_addr = options.listen_addr;
|
|
sin.sin_port = htons(options.port);
|
|
|
|
if (bind(listen_sock, (struct sockaddr *) & sin, sizeof(sin)) < 0) {
|
|
error("bind: %.100s", strerror(errno));
|
|
shutdown(listen_sock, SHUT_RDWR);
|
|
close(listen_sock);
|
|
fatal("Bind to port %d failed.", options.port);
|
|
}
|
|
if (!debug_flag) {
|
|
/*
|
|
* Record our pid in /etc/sshd_pid to make it easier
|
|
* to kill the correct sshd. We don\'t want to do
|
|
* this before the bind above because the bind will
|
|
* fail if there already is a daemon, and this will
|
|
* overwrite any old pid in the file.
|
|
*/
|
|
f = fopen(SSH_DAEMON_PID_FILE, "w");
|
|
if (f) {
|
|
fprintf(f, "%u\n", (unsigned int) getpid());
|
|
fclose(f);
|
|
}
|
|
}
|
|
|
|
log("Server listening on port %d.", options.port);
|
|
if (listen(listen_sock, 5) < 0)
|
|
fatal("listen: %.100s", strerror(errno));
|
|
|
|
public_key = RSA_new();
|
|
sensitive_data.private_key = RSA_new();
|
|
|
|
log("Generating %d bit RSA key.", options.server_key_bits);
|
|
rsa_generate_key(sensitive_data.private_key, public_key,
|
|
options.server_key_bits);
|
|
arc4random_stir();
|
|
log("RSA key generation complete.");
|
|
|
|
/* Schedule server key regeneration alarm. */
|
|
signal(SIGALRM, key_regeneration_alarm);
|
|
alarm(options.key_regeneration_time);
|
|
|
|
/* Arrange to restart on SIGHUP. The handler needs listen_sock. */
|
|
signal(SIGHUP, sighup_handler);
|
|
signal(SIGTERM, sigterm_handler);
|
|
signal(SIGQUIT, sigterm_handler);
|
|
|
|
/* Arrange SIGCHLD to be caught. */
|
|
signal(SIGCHLD, main_sigchld_handler);
|
|
|
|
/*
|
|
* Stay listening for connections until the system crashes or
|
|
* the daemon is killed with a signal.
|
|
*/
|
|
for (;;) {
|
|
if (received_sighup)
|
|
sighup_restart();
|
|
/* Wait in poll until there is a connection. */
|
|
memset(&fds, 0, sizeof(fds));
|
|
fds.fd = listen_sock;
|
|
fds.events = POLLIN;
|
|
if (poll(&fds, 1, -1) == -1) {
|
|
if (errno == EINTR)
|
|
continue;
|
|
fatal("poll: %.100s", strerror(errno));
|
|
/*NOTREACHED*/
|
|
}
|
|
if (fds.revents == 0)
|
|
continue;
|
|
aux = sizeof(sin);
|
|
newsock = accept(listen_sock, (struct sockaddr *) & sin, &aux);
|
|
if (received_sighup)
|
|
sighup_restart();
|
|
if (newsock < 0) {
|
|
if (errno == EINTR)
|
|
continue;
|
|
error("accept: %.100s", strerror(errno));
|
|
continue;
|
|
}
|
|
/*
|
|
* Got connection. Fork a child to handle it, unless
|
|
* we are in debugging mode.
|
|
*/
|
|
if (debug_flag) {
|
|
/*
|
|
* In debugging mode. Close the listening
|
|
* socket, and start processing the
|
|
* connection without forking.
|
|
*/
|
|
debug("Server will not fork when running in debugging mode.");
|
|
close(listen_sock);
|
|
sock_in = newsock;
|
|
sock_out = newsock;
|
|
pid = getpid();
|
|
break;
|
|
} else {
|
|
/*
|
|
* Normal production daemon. Fork, and have
|
|
* the child process the connection. The
|
|
* parent continues listening.
|
|
*/
|
|
if ((pid = fork()) == 0) {
|
|
/*
|
|
* Child. Close the listening socket, and start using the
|
|
* accepted socket. Reinitialize logging (since our pid has
|
|
* changed). We break out of the loop to handle the connection.
|
|
*/
|
|
close(listen_sock);
|
|
sock_in = newsock;
|
|
sock_out = newsock;
|
|
log_init(av0, options.log_level, options.log_facility, log_stderr);
|
|
break;
|
|
}
|
|
}
|
|
|
|
/* Parent. Stay in the loop. */
|
|
if (pid < 0)
|
|
error("fork: %.100s", strerror(errno));
|
|
else
|
|
debug("Forked child %d.", pid);
|
|
|
|
/* Mark that the key has been used (it was "given" to the child). */
|
|
key_used = 1;
|
|
|
|
arc4random_stir();
|
|
|
|
/* Close the new socket (the child is now taking care of it). */
|
|
close(newsock);
|
|
}
|
|
}
|
|
|
|
/* This is the child processing a new connection. */
|
|
|
|
/*
|
|
* Disable the key regeneration alarm. We will not regenerate the
|
|
* key since we are no longer in a position to give it to anyone. We
|
|
* will not restart on SIGHUP since it no longer makes sense.
|
|
*/
|
|
alarm(0);
|
|
signal(SIGALRM, SIG_DFL);
|
|
signal(SIGHUP, SIG_DFL);
|
|
signal(SIGTERM, SIG_DFL);
|
|
signal(SIGQUIT, SIG_DFL);
|
|
signal(SIGCHLD, SIG_DFL);
|
|
|
|
/*
|
|
* Set socket options for the connection. We want the socket to
|
|
* close as fast as possible without waiting for anything. If the
|
|
* connection is not a socket, these will do nothing.
|
|
*/
|
|
/* setsockopt(sock_in, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */
|
|
linger.l_onoff = 1;
|
|
linger.l_linger = 5;
|
|
setsockopt(sock_in, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger));
|
|
|
|
/*
|
|
* Register our connection. This turns encryption off because we do
|
|
* not have a key.
|
|
*/
|
|
packet_set_connection(sock_in, sock_out);
|
|
|
|
remote_port = get_remote_port();
|
|
remote_ip = get_remote_ipaddr();
|
|
|
|
/* Check whether logins are denied from this host. */
|
|
#ifdef LIBWRAP
|
|
{
|
|
struct request_info req;
|
|
|
|
request_init(&req, RQ_DAEMON, av0, RQ_FILE, sock_in, NULL);
|
|
fromhost(&req);
|
|
|
|
if (!hosts_access(&req)) {
|
|
close(sock_in);
|
|
close(sock_out);
|
|
refuse(&req);
|
|
}
|
|
verbose("Connection from %.500s port %d", eval_client(&req), remote_port);
|
|
}
|
|
#else
|
|
/* Log the connection. */
|
|
verbose("Connection from %.500s port %d", remote_ip, remote_port);
|
|
#endif /* LIBWRAP */
|
|
|
|
/*
|
|
* We don\'t want to listen forever unless the other side
|
|
* successfully authenticates itself. So we set up an alarm which is
|
|
* cleared after successful authentication. A limit of zero
|
|
* indicates no limit. Note that we don\'t set the alarm in debugging
|
|
* mode; it is just annoying to have the server exit just when you
|
|
* are about to discover the bug.
|
|
*/
|
|
signal(SIGALRM, grace_alarm_handler);
|
|
if (!debug_flag)
|
|
alarm(options.login_grace_time);
|
|
|
|
if (client_version_string != NULL) {
|
|
/* we are exec'ed by sshd2, so skip exchange of protocol version */
|
|
strlcpy(buf, client_version_string, sizeof(buf));
|
|
} else {
|
|
/* Send our protocol version identification. */
|
|
snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
|
|
PROTOCOL_MAJOR, PROTOCOL_MINOR, SSH_VERSION);
|
|
if (atomicio(write, sock_out, buf, strlen(buf)) != strlen(buf))
|
|
fatal("Could not write ident string to %s.", get_remote_ipaddr());
|
|
|
|
/* Read other side\'s version identification. */
|
|
for (i = 0; i < sizeof(buf) - 1; i++) {
|
|
if (read(sock_in, &buf[i], 1) != 1)
|
|
fatal("Did not receive ident string from %s.", get_remote_ipaddr());
|
|
if (buf[i] == '\r') {
|
|
buf[i] = '\n';
|
|
buf[i + 1] = 0;
|
|
break;
|
|
}
|
|
if (buf[i] == '\n') {
|
|
/* buf[i] == '\n' */
|
|
buf[i + 1] = 0;
|
|
break;
|
|
}
|
|
}
|
|
buf[sizeof(buf) - 1] = 0;
|
|
}
|
|
|
|
/*
|
|
* Check that the versions match. In future this might accept
|
|
* several versions and set appropriate flags to handle them.
|
|
*/
|
|
if (sscanf(buf, "SSH-%d.%d-%[^\n]\n", &remote_major, &remote_minor,
|
|
remote_version) != 3) {
|
|
char *s = "Protocol mismatch.\n";
|
|
|
|
(void) atomicio(write, sock_out, s, strlen(s));
|
|
close(sock_in);
|
|
close(sock_out);
|
|
fatal("Bad protocol version identification '%.100s' from %s",
|
|
buf, get_remote_ipaddr());
|
|
}
|
|
debug("Client protocol version %d.%d; client software version %.100s",
|
|
remote_major, remote_minor, remote_version);
|
|
if (remote_major != PROTOCOL_MAJOR) {
|
|
char *s = "Protocol major versions differ.\n";
|
|
|
|
(void) atomicio(write, sock_out, s, strlen(s));
|
|
close(sock_in);
|
|
close(sock_out);
|
|
fatal("Protocol major versions differ for %s: %d vs. %d",
|
|
get_remote_ipaddr(),
|
|
PROTOCOL_MAJOR, remote_major);
|
|
}
|
|
/* Check that the client has sufficiently high software version. */
|
|
if (remote_major == 1 && remote_minor < 3)
|
|
packet_disconnect("Your ssh version is too old and is no longer supported. Please install a newer version.");
|
|
|
|
if (remote_major == 1 && remote_minor == 3) {
|
|
enable_compat13();
|
|
if (strcmp(remote_version, "OpenSSH-1.1") != 0) {
|
|
debug("Agent forwarding disabled, remote version is not compatible.");
|
|
no_agent_forwarding_flag = 1;
|
|
}
|
|
}
|
|
/*
|
|
* Check that the connection comes from a privileged port. Rhosts-
|
|
* and Rhosts-RSA-Authentication only make sense from priviledged
|
|
* programs. Of course, if the intruder has root access on his local
|
|
* machine, he can connect from any port. So do not use these
|
|
* authentication methods from machines that you do not trust.
|
|
*/
|
|
if (remote_port >= IPPORT_RESERVED ||
|
|
remote_port < IPPORT_RESERVED / 2) {
|
|
options.rhosts_authentication = 0;
|
|
options.rhosts_rsa_authentication = 0;
|
|
}
|
|
packet_set_nonblocking();
|
|
|
|
/* Handle the connection. */
|
|
do_connection();
|
|
|
|
#ifdef KRB4
|
|
/* Cleanup user's ticket cache file. */
|
|
if (options.kerberos_ticket_cleanup)
|
|
(void) dest_tkt();
|
|
#endif /* KRB4 */
|
|
|
|
/* Cleanup user's local Xauthority file. */
|
|
if (xauthfile)
|
|
unlink(xauthfile);
|
|
|
|
/* The connection has been terminated. */
|
|
verbose("Closing connection to %.100s", remote_ip);
|
|
|
|
#ifdef USE_PAM
|
|
{
|
|
int retval;
|
|
|
|
if (pamh != NULL) {
|
|
debug("Closing PAM session.");
|
|
retval = pam_close_session((pam_handle_t *)pamh, 0);
|
|
|
|
debug("Terminating PAM library.");
|
|
if (pam_end((pam_handle_t *)pamh, retval) != PAM_SUCCESS)
|
|
log("Cannot release PAM authentication.");
|
|
|
|
fatal_remove_cleanup(&pam_cleanup_proc, NULL);
|
|
}
|
|
}
|
|
#endif /* USE_PAM */
|
|
|
|
packet_close();
|
|
exit(0);
|
|
}
|
|
|
|
/*
|
|
* Process an incoming connection. Protocol version identifiers have already
|
|
* been exchanged. This sends server key and performs the key exchange.
|
|
* Server and host keys will no longer be needed after this functions.
|
|
*/
|
|
void
|
|
do_connection()
|
|
{
|
|
int i, len;
|
|
BIGNUM *session_key_int;
|
|
unsigned char session_key[SSH_SESSION_KEY_LENGTH];
|
|
unsigned char check_bytes[8];
|
|
char *user;
|
|
unsigned int cipher_type, auth_mask, protocol_flags;
|
|
int plen, slen, ulen;
|
|
u_int32_t rand = 0;
|
|
|
|
/*
|
|
* Generate check bytes that the client must send back in the user
|
|
* packet in order for it to be accepted; this is used to defy ip
|
|
* spoofing attacks. Note that this only works against somebody
|
|
* doing IP spoofing from a remote machine; any machine on the local
|
|
* network can still see outgoing packets and catch the random
|
|
* cookie. This only affects rhosts authentication, and this is one
|
|
* of the reasons why it is inherently insecure.
|
|
*/
|
|
for (i = 0; i < 8; i++) {
|
|
if (i % 4 == 0)
|
|
rand = arc4random();
|
|
check_bytes[i] = rand & 0xff;
|
|
rand >>= 8;
|
|
}
|
|
|
|
/*
|
|
* Send our public key. We include in the packet 64 bits of random
|
|
* data that must be matched in the reply in order to prevent IP
|
|
* spoofing.
|
|
*/
|
|
packet_start(SSH_SMSG_PUBLIC_KEY);
|
|
for (i = 0; i < 8; i++)
|
|
packet_put_char(check_bytes[i]);
|
|
|
|
/* Store our public server RSA key. */
|
|
packet_put_int(BN_num_bits(public_key->n));
|
|
packet_put_bignum(public_key->e);
|
|
packet_put_bignum(public_key->n);
|
|
|
|
/* Store our public host RSA key. */
|
|
packet_put_int(BN_num_bits(sensitive_data.host_key->n));
|
|
packet_put_bignum(sensitive_data.host_key->e);
|
|
packet_put_bignum(sensitive_data.host_key->n);
|
|
|
|
/* Put protocol flags. */
|
|
packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
|
|
|
|
/* Declare which ciphers we support. */
|
|
packet_put_int(cipher_mask());
|
|
|
|
/* Declare supported authentication types. */
|
|
auth_mask = 0;
|
|
if (options.rhosts_authentication)
|
|
auth_mask |= 1 << SSH_AUTH_RHOSTS;
|
|
if (options.rhosts_rsa_authentication)
|
|
auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
|
|
if (options.rsa_authentication)
|
|
auth_mask |= 1 << SSH_AUTH_RSA;
|
|
#ifdef KRB4
|
|
if (options.kerberos_authentication)
|
|
auth_mask |= 1 << SSH_AUTH_KERBEROS;
|
|
#endif
|
|
#ifdef AFS
|
|
if (options.kerberos_tgt_passing)
|
|
auth_mask |= 1 << SSH_PASS_KERBEROS_TGT;
|
|
if (options.afs_token_passing)
|
|
auth_mask |= 1 << SSH_PASS_AFS_TOKEN;
|
|
#endif
|
|
#ifdef SKEY
|
|
if (options.skey_authentication == 1)
|
|
auth_mask |= 1 << SSH_AUTH_TIS;
|
|
#endif
|
|
if (options.password_authentication)
|
|
auth_mask |= 1 << SSH_AUTH_PASSWORD;
|
|
packet_put_int(auth_mask);
|
|
|
|
/* Send the packet and wait for it to be sent. */
|
|
packet_send();
|
|
packet_write_wait();
|
|
|
|
debug("Sent %d bit public key and %d bit host key.",
|
|
BN_num_bits(public_key->n), BN_num_bits(sensitive_data.host_key->n));
|
|
|
|
/* Read clients reply (cipher type and session key). */
|
|
packet_read_expect(&plen, SSH_CMSG_SESSION_KEY);
|
|
|
|
/* Get cipher type and check whether we accept this. */
|
|
cipher_type = packet_get_char();
|
|
|
|
if (!(cipher_mask() & (1 << cipher_type)))
|
|
packet_disconnect("Warning: client selects unsupported cipher.");
|
|
|
|
/* Get check bytes from the packet. These must match those we
|
|
sent earlier with the public key packet. */
|
|
for (i = 0; i < 8; i++)
|
|
if (check_bytes[i] != packet_get_char())
|
|
packet_disconnect("IP Spoofing check bytes do not match.");
|
|
|
|
debug("Encryption type: %.200s", cipher_name(cipher_type));
|
|
|
|
/* Get the encrypted integer. */
|
|
session_key_int = BN_new();
|
|
packet_get_bignum(session_key_int, &slen);
|
|
|
|
protocol_flags = packet_get_int();
|
|
packet_set_protocol_flags(protocol_flags);
|
|
|
|
packet_integrity_check(plen, 1 + 8 + slen + 4, SSH_CMSG_SESSION_KEY);
|
|
|
|
/*
|
|
* Decrypt it using our private server key and private host key (key
|
|
* with larger modulus first).
|
|
*/
|
|
if (BN_cmp(sensitive_data.private_key->n, sensitive_data.host_key->n) > 0) {
|
|
/* Private key has bigger modulus. */
|
|
if (BN_num_bits(sensitive_data.private_key->n) <
|
|
BN_num_bits(sensitive_data.host_key->n) + SSH_KEY_BITS_RESERVED) {
|
|
fatal("do_connection: %s: private_key %d < host_key %d + SSH_KEY_BITS_RESERVED %d",
|
|
get_remote_ipaddr(),
|
|
BN_num_bits(sensitive_data.private_key->n),
|
|
BN_num_bits(sensitive_data.host_key->n),
|
|
SSH_KEY_BITS_RESERVED);
|
|
}
|
|
rsa_private_decrypt(session_key_int, session_key_int,
|
|
sensitive_data.private_key);
|
|
rsa_private_decrypt(session_key_int, session_key_int,
|
|
sensitive_data.host_key);
|
|
} else {
|
|
/* Host key has bigger modulus (or they are equal). */
|
|
if (BN_num_bits(sensitive_data.host_key->n) <
|
|
BN_num_bits(sensitive_data.private_key->n) + SSH_KEY_BITS_RESERVED) {
|
|
fatal("do_connection: %s: host_key %d < private_key %d + SSH_KEY_BITS_RESERVED %d",
|
|
get_remote_ipaddr(),
|
|
BN_num_bits(sensitive_data.host_key->n),
|
|
BN_num_bits(sensitive_data.private_key->n),
|
|
SSH_KEY_BITS_RESERVED);
|
|
}
|
|
rsa_private_decrypt(session_key_int, session_key_int,
|
|
sensitive_data.host_key);
|
|
rsa_private_decrypt(session_key_int, session_key_int,
|
|
sensitive_data.private_key);
|
|
}
|
|
|
|
compute_session_id(session_id, check_bytes,
|
|
sensitive_data.host_key->n,
|
|
sensitive_data.private_key->n);
|
|
|
|
/*
|
|
* Extract session key from the decrypted integer. The key is in the
|
|
* least significant 256 bits of the integer; the first byte of the
|
|
* key is in the highest bits.
|
|
*/
|
|
BN_mask_bits(session_key_int, sizeof(session_key) * 8);
|
|
len = BN_num_bytes(session_key_int);
|
|
if (len < 0 || len > sizeof(session_key))
|
|
fatal("do_connection: bad len from %s: session_key_int %d > sizeof(session_key) %d",
|
|
get_remote_ipaddr(),
|
|
len, sizeof(session_key));
|
|
memset(session_key, 0, sizeof(session_key));
|
|
BN_bn2bin(session_key_int, session_key + sizeof(session_key) - len);
|
|
|
|
/* Xor the first 16 bytes of the session key with the session id. */
|
|
for (i = 0; i < 16; i++)
|
|
session_key[i] ^= session_id[i];
|
|
|
|
/* Destroy the decrypted integer. It is no longer needed. */
|
|
BN_clear_free(session_key_int);
|
|
|
|
/* Set the session key. From this on all communications will be encrypted. */
|
|
packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
|
|
|
|
/* Destroy our copy of the session key. It is no longer needed. */
|
|
memset(session_key, 0, sizeof(session_key));
|
|
|
|
debug("Received session key; encryption turned on.");
|
|
|
|
/* Send an acknowledgement packet. Note that this packet is sent encrypted. */
|
|
packet_start(SSH_SMSG_SUCCESS);
|
|
packet_send();
|
|
packet_write_wait();
|
|
|
|
/* Get the name of the user that we wish to log in as. */
|
|
packet_read_expect(&plen, SSH_CMSG_USER);
|
|
|
|
/* Get the user name. */
|
|
user = packet_get_string(&ulen);
|
|
packet_integrity_check(plen, (4 + ulen), SSH_CMSG_USER);
|
|
|
|
/* Destroy the private and public keys. They will no longer be needed. */
|
|
RSA_free(public_key);
|
|
RSA_free(sensitive_data.private_key);
|
|
RSA_free(sensitive_data.host_key);
|
|
|
|
setproctitle("%s", user);
|
|
/* Do the authentication. */
|
|
do_authentication(user);
|
|
}
|
|
|
|
/*
|
|
* Check if the user is allowed to log in via ssh. If user is listed in
|
|
* DenyUsers or user's primary group is listed in DenyGroups, false will
|
|
* be returned. If AllowUsers isn't empty and user isn't listed there, or
|
|
* if AllowGroups isn't empty and user isn't listed there, false will be
|
|
* returned. Otherwise true is returned.
|
|
* XXX This function should also check if user has a valid shell
|
|
*/
|
|
static int
|
|
allowed_user(struct passwd * pw)
|
|
{
|
|
struct group *grp;
|
|
int i;
|
|
|
|
/* Shouldn't be called if pw is NULL, but better safe than sorry... */
|
|
if (!pw)
|
|
return 0;
|
|
|
|
/* XXX Should check for valid login shell */
|
|
|
|
/* Return false if user is listed in DenyUsers */
|
|
if (options.num_deny_users > 0) {
|
|
if (!pw->pw_name)
|
|
return 0;
|
|
for (i = 0; i < options.num_deny_users; i++)
|
|
if (match_pattern(pw->pw_name, options.deny_users[i]))
|
|
return 0;
|
|
}
|
|
/* Return false if AllowUsers isn't empty and user isn't listed there */
|
|
if (options.num_allow_users > 0) {
|
|
if (!pw->pw_name)
|
|
return 0;
|
|
for (i = 0; i < options.num_allow_users; i++)
|
|
if (match_pattern(pw->pw_name, options.allow_users[i]))
|
|
break;
|
|
/* i < options.num_allow_users iff we break for loop */
|
|
if (i >= options.num_allow_users)
|
|
return 0;
|
|
}
|
|
/* Get the primary group name if we need it. Return false if it fails */
|
|
if (options.num_deny_groups > 0 || options.num_allow_groups > 0) {
|
|
grp = getgrgid(pw->pw_gid);
|
|
if (!grp)
|
|
return 0;
|
|
|
|
/* Return false if user's group is listed in DenyGroups */
|
|
if (options.num_deny_groups > 0) {
|
|
if (!grp->gr_name)
|
|
return 0;
|
|
for (i = 0; i < options.num_deny_groups; i++)
|
|
if (match_pattern(grp->gr_name, options.deny_groups[i]))
|
|
return 0;
|
|
}
|
|
/*
|
|
* Return false if AllowGroups isn't empty and user's group
|
|
* isn't listed there
|
|
*/
|
|
if (options.num_allow_groups > 0) {
|
|
if (!grp->gr_name)
|
|
return 0;
|
|
for (i = 0; i < options.num_allow_groups; i++)
|
|
if (match_pattern(grp->gr_name, options.allow_groups[i]))
|
|
break;
|
|
/* i < options.num_allow_groups iff we break for
|
|
loop */
|
|
if (i >= options.num_allow_groups)
|
|
return 0;
|
|
}
|
|
}
|
|
/* We found no reason not to let this user try to log on... */
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Performs authentication of an incoming connection. Session key has already
|
|
* been exchanged and encryption is enabled. User is the user name to log
|
|
* in as (received from the client).
|
|
*/
|
|
void
|
|
do_authentication(char *user)
|
|
{
|
|
struct passwd *pw, pwcopy;
|
|
|
|
#ifdef AFS
|
|
/* If machine has AFS, set process authentication group. */
|
|
if (k_hasafs()) {
|
|
k_setpag();
|
|
k_unlog();
|
|
}
|
|
#endif /* AFS */
|
|
|
|
/* Verify that the user is a valid user. */
|
|
pw = getpwnam(user);
|
|
if (!pw || !allowed_user(pw))
|
|
do_fake_authloop(user);
|
|
|
|
/* Take a copy of the returned structure. */
|
|
memset(&pwcopy, 0, sizeof(pwcopy));
|
|
pwcopy.pw_name = xstrdup(pw->pw_name);
|
|
pwcopy.pw_passwd = xstrdup(pw->pw_passwd);
|
|
pwcopy.pw_uid = pw->pw_uid;
|
|
pwcopy.pw_gid = pw->pw_gid;
|
|
pwcopy.pw_dir = xstrdup(pw->pw_dir);
|
|
pwcopy.pw_shell = xstrdup(pw->pw_shell);
|
|
pw = &pwcopy;
|
|
|
|
#ifdef USE_PAM
|
|
{
|
|
int pam_retval;
|
|
|
|
debug("Starting up PAM with username \"%.200s\"", pw->pw_name);
|
|
|
|
pam_retval = pam_start("sshd", pw->pw_name, &conv, (pam_handle_t**)&pamh);
|
|
if (pam_retval != PAM_SUCCESS)
|
|
fatal("PAM initialisation failed: %.200s", PAM_STRERROR((pam_handle_t *)pamh, pam_retval));
|
|
|
|
fatal_add_cleanup(&pam_cleanup_proc, NULL);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* If we are not running as root, the user must have the same uid as
|
|
* the server.
|
|
*/
|
|
if (getuid() != 0 && pw->pw_uid != getuid())
|
|
packet_disconnect("Cannot change user when server not running as root.");
|
|
|
|
debug("Attempting authentication for %.100s.", user);
|
|
|
|
/* If the user has no password, accept authentication immediately. */
|
|
if (options.password_authentication &&
|
|
#ifdef KRB4
|
|
(!options.kerberos_authentication || options.kerberos_or_local_passwd) &&
|
|
#endif /* KRB4 */
|
|
#ifdef USE_PAM
|
|
do_pam_auth(pw->pw_name, "")) {
|
|
#else /* USE_PAM */
|
|
auth_password(pw, "")) {
|
|
#endif /* USE_PAM */
|
|
/* Authentication with empty password succeeded. */
|
|
log("Login for user %s from %.100s, accepted without authentication.",
|
|
pw->pw_name, get_remote_ipaddr());
|
|
} else {
|
|
/* Loop until the user has been authenticated or the
|
|
connection is closed, do_authloop() returns only if
|
|
authentication is successfull */
|
|
do_authloop(pw);
|
|
}
|
|
|
|
/* Check if the user is logging in as root and root logins are disallowed. */
|
|
if (pw->pw_uid == 0 && !options.permit_root_login) {
|
|
if (forced_command)
|
|
log("Root login accepted for forced command.");
|
|
else
|
|
packet_disconnect("ROOT LOGIN REFUSED FROM %.200s",
|
|
get_canonical_hostname());
|
|
}
|
|
/* The user has been authenticated and accepted. */
|
|
packet_start(SSH_SMSG_SUCCESS);
|
|
packet_send();
|
|
packet_write_wait();
|
|
|
|
/* Perform session preparation. */
|
|
do_authenticated(pw);
|
|
}
|
|
|
|
#define AUTH_FAIL_MAX 6
|
|
#define AUTH_FAIL_LOG (AUTH_FAIL_MAX/2)
|
|
#define AUTH_FAIL_MSG "Too many authentication failures for %.100s"
|
|
|
|
/*
|
|
* read packets and try to authenticate local user *pw.
|
|
* return if authentication is successfull
|
|
*/
|
|
void
|
|
do_authloop(struct passwd * pw)
|
|
{
|
|
int attempt = 0;
|
|
unsigned int bits;
|
|
BIGNUM *client_host_key_e, *client_host_key_n;
|
|
BIGNUM *n;
|
|
char *client_user = NULL, *password = NULL;
|
|
char user[1024];
|
|
int plen, dlen, nlen, ulen, elen;
|
|
int type = 0;
|
|
void (*authlog) (const char *fmt,...) = verbose;
|
|
|
|
/* Indicate that authentication is needed. */
|
|
packet_start(SSH_SMSG_FAILURE);
|
|
packet_send();
|
|
packet_write_wait();
|
|
|
|
for (attempt = 1;; attempt++) {
|
|
int authenticated = 0;
|
|
strlcpy(user, "", sizeof user);
|
|
|
|
/* Get a packet from the client. */
|
|
type = packet_read(&plen);
|
|
|
|
/* Process the packet. */
|
|
switch (type) {
|
|
#ifdef AFS
|
|
case SSH_CMSG_HAVE_KERBEROS_TGT:
|
|
if (!options.kerberos_tgt_passing) {
|
|
/* packet_get_all(); */
|
|
verbose("Kerberos tgt passing disabled.");
|
|
break;
|
|
} else {
|
|
/* Accept Kerberos tgt. */
|
|
char *tgt = packet_get_string(&dlen);
|
|
packet_integrity_check(plen, 4 + dlen, type);
|
|
if (!auth_kerberos_tgt(pw, tgt))
|
|
verbose("Kerberos tgt REFUSED for %s", pw->pw_name);
|
|
xfree(tgt);
|
|
}
|
|
continue;
|
|
|
|
case SSH_CMSG_HAVE_AFS_TOKEN:
|
|
if (!options.afs_token_passing || !k_hasafs()) {
|
|
/* packet_get_all(); */
|
|
verbose("AFS token passing disabled.");
|
|
break;
|
|
} else {
|
|
/* Accept AFS token. */
|
|
char *token_string = packet_get_string(&dlen);
|
|
packet_integrity_check(plen, 4 + dlen, type);
|
|
if (!auth_afs_token(pw, token_string))
|
|
verbose("AFS token REFUSED for %s", pw->pw_name);
|
|
xfree(token_string);
|
|
}
|
|
continue;
|
|
#endif /* AFS */
|
|
#ifdef KRB4
|
|
case SSH_CMSG_AUTH_KERBEROS:
|
|
if (!options.kerberos_authentication) {
|
|
/* packet_get_all(); */
|
|
verbose("Kerberos authentication disabled.");
|
|
break;
|
|
} else {
|
|
/* Try Kerberos v4 authentication. */
|
|
KTEXT_ST auth;
|
|
char *tkt_user = NULL;
|
|
char *kdata = packet_get_string((unsigned int *) &auth.length);
|
|
packet_integrity_check(plen, 4 + auth.length, type);
|
|
|
|
if (auth.length < MAX_KTXT_LEN)
|
|
memcpy(auth.dat, kdata, auth.length);
|
|
xfree(kdata);
|
|
|
|
authenticated = auth_krb4(pw->pw_name, &auth, &tkt_user);
|
|
|
|
if (authenticated) {
|
|
snprintf(user, sizeof user, " tktuser %s", tkt_user);
|
|
xfree(tkt_user);
|
|
}
|
|
}
|
|
break;
|
|
#endif /* KRB4 */
|
|
|
|
case SSH_CMSG_AUTH_RHOSTS:
|
|
if (!options.rhosts_authentication) {
|
|
verbose("Rhosts authentication disabled.");
|
|
break;
|
|
}
|
|
/*
|
|
* Get client user name. Note that we just have to
|
|
* trust the client; this is one reason why rhosts
|
|
* authentication is insecure. (Another is
|
|
* IP-spoofing on a local network.)
|
|
*/
|
|
client_user = packet_get_string(&ulen);
|
|
packet_integrity_check(plen, 4 + ulen, type);
|
|
|
|
/* Try to authenticate using /etc/hosts.equiv and
|
|
.rhosts. */
|
|
authenticated = auth_rhosts(pw, client_user);
|
|
|
|
snprintf(user, sizeof user, " ruser %s", client_user);
|
|
#ifndef USE_PAM
|
|
xfree(client_user);
|
|
#endif /* USE_PAM */
|
|
break;
|
|
|
|
case SSH_CMSG_AUTH_RHOSTS_RSA:
|
|
if (!options.rhosts_rsa_authentication) {
|
|
verbose("Rhosts with RSA authentication disabled.");
|
|
break;
|
|
}
|
|
/*
|
|
* Get client user name. Note that we just have to
|
|
* trust the client; root on the client machine can
|
|
* claim to be any user.
|
|
*/
|
|
client_user = packet_get_string(&ulen);
|
|
|
|
/* Get the client host key. */
|
|
client_host_key_e = BN_new();
|
|
client_host_key_n = BN_new();
|
|
bits = packet_get_int();
|
|
packet_get_bignum(client_host_key_e, &elen);
|
|
packet_get_bignum(client_host_key_n, &nlen);
|
|
|
|
if (bits != BN_num_bits(client_host_key_n))
|
|
error("Warning: keysize mismatch for client_host_key: "
|
|
"actual %d, announced %d", BN_num_bits(client_host_key_n), bits);
|
|
packet_integrity_check(plen, (4 + ulen) + 4 + elen + nlen, type);
|
|
|
|
authenticated = auth_rhosts_rsa(pw, client_user,
|
|
client_host_key_e, client_host_key_n);
|
|
BN_clear_free(client_host_key_e);
|
|
BN_clear_free(client_host_key_n);
|
|
|
|
snprintf(user, sizeof user, " ruser %s", client_user);
|
|
#ifndef USE_PAM
|
|
xfree(client_user);
|
|
#endif /* USE_PAM */
|
|
break;
|
|
|
|
case SSH_CMSG_AUTH_RSA:
|
|
if (!options.rsa_authentication) {
|
|
verbose("RSA authentication disabled.");
|
|
break;
|
|
}
|
|
/* RSA authentication requested. */
|
|
n = BN_new();
|
|
packet_get_bignum(n, &nlen);
|
|
packet_integrity_check(plen, nlen, type);
|
|
authenticated = auth_rsa(pw, n);
|
|
BN_clear_free(n);
|
|
break;
|
|
|
|
case SSH_CMSG_AUTH_PASSWORD:
|
|
if (!options.password_authentication) {
|
|
verbose("Password authentication disabled.");
|
|
break;
|
|
}
|
|
/*
|
|
* Read user password. It is in plain text, but was
|
|
* transmitted over the encrypted channel so it is
|
|
* not visible to an outside observer.
|
|
*/
|
|
password = packet_get_string(&dlen);
|
|
packet_integrity_check(plen, 4 + dlen, type);
|
|
|
|
#ifdef USE_PAM
|
|
/* Do PAM auth with password */
|
|
authenticated = do_pam_auth(pw->pw_name, password);
|
|
#else /* USE_PAM */
|
|
/* Try authentication with the password. */
|
|
authenticated = auth_password(pw, password);
|
|
#endif /* USE_PAM */
|
|
memset(password, 0, strlen(password));
|
|
xfree(password);
|
|
break;
|
|
|
|
#ifdef SKEY
|
|
case SSH_CMSG_AUTH_TIS:
|
|
debug("rcvd SSH_CMSG_AUTH_TIS");
|
|
if (options.skey_authentication == 1) {
|
|
char *skeyinfo = skey_keyinfo(pw->pw_name);
|
|
if (skeyinfo == NULL) {
|
|
debug("generating fake skeyinfo for %.100s.", pw->pw_name);
|
|
skeyinfo = skey_fake_keyinfo(pw->pw_name);
|
|
}
|
|
if (skeyinfo != NULL) {
|
|
/* we send our s/key- in tis-challenge messages */
|
|
debug("sending challenge '%s'", skeyinfo);
|
|
packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE);
|
|
packet_put_string(skeyinfo, strlen(skeyinfo));
|
|
packet_send();
|
|
packet_write_wait();
|
|
continue;
|
|
}
|
|
}
|
|
break;
|
|
case SSH_CMSG_AUTH_TIS_RESPONSE:
|
|
debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE");
|
|
if (options.skey_authentication == 1) {
|
|
char *response = packet_get_string(&dlen);
|
|
debug("skey response == '%s'", response);
|
|
packet_integrity_check(plen, 4 + dlen, type);
|
|
authenticated = (skey_haskey(pw->pw_name) == 0 &&
|
|
skey_passcheck(pw->pw_name, response) != -1);
|
|
xfree(response);
|
|
}
|
|
break;
|
|
#else
|
|
case SSH_CMSG_AUTH_TIS:
|
|
/* TIS Authentication is unsupported */
|
|
log("TIS authentication unsupported.");
|
|
break;
|
|
#endif
|
|
|
|
default:
|
|
/*
|
|
* Any unknown messages will be ignored (and failure
|
|
* returned) during authentication.
|
|
*/
|
|
log("Unknown message during authentication: type %d", type);
|
|
break;
|
|
}
|
|
|
|
/* Raise logging level */
|
|
if (authenticated ||
|
|
attempt == AUTH_FAIL_LOG ||
|
|
type == SSH_CMSG_AUTH_PASSWORD)
|
|
authlog = log;
|
|
|
|
authlog("%s %s for %.200s from %.200s port %d%s",
|
|
authenticated ? "Accepted" : "Failed",
|
|
get_authname(type),
|
|
pw->pw_uid == 0 ? "ROOT" : pw->pw_name,
|
|
get_remote_ipaddr(),
|
|
get_remote_port(),
|
|
user);
|
|
|
|
#ifndef USE_PAM
|
|
if (authenticated)
|
|
return;
|
|
|
|
if (attempt > AUTH_FAIL_MAX)
|
|
packet_disconnect(AUTH_FAIL_MSG, pw->pw_name);
|
|
#else /* USE_PAM */
|
|
if (authenticated) {
|
|
do_pam_account(pw->pw_name, client_user);
|
|
|
|
if (client_user != NULL)
|
|
xfree(client_user);
|
|
|
|
return;
|
|
}
|
|
|
|
if (attempt > AUTH_FAIL_MAX) {
|
|
if (client_user != NULL)
|
|
xfree(client_user);
|
|
|
|
packet_disconnect(AUTH_FAIL_MSG, pw->pw_name);
|
|
}
|
|
#endif /* USE_PAM */
|
|
|
|
/* Send a message indicating that the authentication attempt failed. */
|
|
packet_start(SSH_SMSG_FAILURE);
|
|
packet_send();
|
|
packet_write_wait();
|
|
}
|
|
}
|
|
|
|
/*
|
|
* The user does not exist or access is denied,
|
|
* but fake indication that authentication is needed.
|
|
*/
|
|
void
|
|
do_fake_authloop(char *user)
|
|
{
|
|
int attempt = 0;
|
|
|
|
log("Faking authloop for illegal user %.200s from %.200s port %d",
|
|
user,
|
|
get_remote_ipaddr(),
|
|
get_remote_port());
|
|
|
|
/* Indicate that authentication is needed. */
|
|
packet_start(SSH_SMSG_FAILURE);
|
|
packet_send();
|
|
packet_write_wait();
|
|
|
|
/*
|
|
* Keep reading packets, and always respond with a failure. This is
|
|
* to avoid disclosing whether such a user really exists.
|
|
*/
|
|
for (attempt = 1;; attempt++) {
|
|
/* Read a packet. This will not return if the client disconnects. */
|
|
int plen;
|
|
int type = packet_read(&plen);
|
|
#ifdef SKEY
|
|
int dlen;
|
|
char *password, *skeyinfo;
|
|
/* Try to send a fake s/key challenge. */
|
|
if (options.skey_authentication == 1 &&
|
|
(skeyinfo = skey_fake_keyinfo(user)) != NULL) {
|
|
if (type == SSH_CMSG_AUTH_TIS) {
|
|
packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE);
|
|
packet_put_string(skeyinfo, strlen(skeyinfo));
|
|
packet_send();
|
|
packet_write_wait();
|
|
continue;
|
|
} else if (type == SSH_CMSG_AUTH_PASSWORD &&
|
|
options.password_authentication &&
|
|
(password = packet_get_string(&dlen)) != NULL &&
|
|
dlen == 5 &&
|
|
strncasecmp(password, "s/key", 5) == 0 ) {
|
|
packet_send_debug(skeyinfo);
|
|
}
|
|
}
|
|
#endif
|
|
if (attempt > AUTH_FAIL_MAX)
|
|
packet_disconnect(AUTH_FAIL_MSG, user);
|
|
|
|
/*
|
|
* Send failure. This should be indistinguishable from a
|
|
* failed authentication.
|
|
*/
|
|
packet_start(SSH_SMSG_FAILURE);
|
|
packet_send();
|
|
packet_write_wait();
|
|
}
|
|
/* NOTREACHED */
|
|
abort();
|
|
}
|
|
|
|
|
|
/*
|
|
* Remove local Xauthority file.
|
|
*/
|
|
static void
|
|
xauthfile_cleanup_proc(void *ignore)
|
|
{
|
|
debug("xauthfile_cleanup_proc called");
|
|
|
|
if (xauthfile != NULL) {
|
|
unlink(xauthfile);
|
|
xfree(xauthfile);
|
|
xauthfile = NULL;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Prepares for an interactive session. This is called after the user has
|
|
* been successfully authenticated. During this message exchange, pseudo
|
|
* terminals are allocated, X11, TCP/IP, and authentication agent forwardings
|
|
* are requested, etc.
|
|
*/
|
|
void
|
|
do_authenticated(struct passwd * pw)
|
|
{
|
|
int type;
|
|
int compression_level = 0, enable_compression_after_reply = 0;
|
|
int have_pty = 0, ptyfd = -1, ttyfd = -1, xauthfd = -1;
|
|
int row, col, xpixel, ypixel, screen;
|
|
char ttyname[64];
|
|
char *command, *term = NULL, *display = NULL, *proto = NULL,
|
|
*data = NULL;
|
|
struct group *grp;
|
|
gid_t tty_gid;
|
|
mode_t tty_mode;
|
|
int n_bytes;
|
|
|
|
/*
|
|
* Cancel the alarm we set to limit the time taken for
|
|
* authentication.
|
|
*/
|
|
alarm(0);
|
|
|
|
/*
|
|
* Inform the channel mechanism that we are the server side and that
|
|
* the client may request to connect to any port at all. (The user
|
|
* could do it anyway, and we wouldn\'t know what is permitted except
|
|
* by the client telling us, so we can equally well trust the client
|
|
* not to request anything bogus.)
|
|
*/
|
|
channel_permit_all_opens();
|
|
|
|
/*
|
|
* We stay in this loop until the client requests to execute a shell
|
|
* or a command.
|
|
*/
|
|
while (1) {
|
|
int plen, dlen;
|
|
|
|
/* Get a packet from the client. */
|
|
type = packet_read(&plen);
|
|
|
|
/* Process the packet. */
|
|
switch (type) {
|
|
case SSH_CMSG_REQUEST_COMPRESSION:
|
|
packet_integrity_check(plen, 4, type);
|
|
compression_level = packet_get_int();
|
|
if (compression_level < 1 || compression_level > 9) {
|
|
packet_send_debug("Received illegal compression level %d.",
|
|
compression_level);
|
|
goto fail;
|
|
}
|
|
/* Enable compression after we have responded with SUCCESS. */
|
|
enable_compression_after_reply = 1;
|
|
break;
|
|
|
|
case SSH_CMSG_REQUEST_PTY:
|
|
if (no_pty_flag) {
|
|
debug("Allocating a pty not permitted for this authentication.");
|
|
goto fail;
|
|
}
|
|
if (have_pty)
|
|
packet_disconnect("Protocol error: you already have a pty.");
|
|
|
|
debug("Allocating pty.");
|
|
|
|
/* Allocate a pty and open it. */
|
|
if (!pty_allocate(&ptyfd, &ttyfd, ttyname,
|
|
sizeof(ttyname))) {
|
|
error("Failed to allocate pty.");
|
|
goto fail;
|
|
}
|
|
/* Determine the group to make the owner of the tty. */
|
|
grp = getgrnam("tty");
|
|
if (grp) {
|
|
tty_gid = grp->gr_gid;
|
|
tty_mode = S_IRUSR | S_IWUSR | S_IWGRP;
|
|
} else {
|
|
tty_gid = pw->pw_gid;
|
|
tty_mode = S_IRUSR | S_IWUSR | S_IWGRP | S_IWOTH;
|
|
}
|
|
|
|
/* Change ownership of the tty. */
|
|
if (chown(ttyname, pw->pw_uid, tty_gid) < 0)
|
|
fatal("chown(%.100s, %d, %d) failed: %.100s",
|
|
ttyname, pw->pw_uid, tty_gid, strerror(errno));
|
|
if (chmod(ttyname, tty_mode) < 0)
|
|
fatal("chmod(%.100s, 0%o) failed: %.100s",
|
|
ttyname, tty_mode, strerror(errno));
|
|
|
|
/* Get TERM from the packet. Note that the value may be of arbitrary length. */
|
|
term = packet_get_string(&dlen);
|
|
packet_integrity_check(dlen, strlen(term), type);
|
|
/* packet_integrity_check(plen, 4 + dlen + 4*4 + n_bytes, type); */
|
|
/* Remaining bytes */
|
|
n_bytes = plen - (4 + dlen + 4 * 4);
|
|
|
|
if (strcmp(term, "") == 0)
|
|
term = NULL;
|
|
|
|
/* Get window size from the packet. */
|
|
row = packet_get_int();
|
|
col = packet_get_int();
|
|
xpixel = packet_get_int();
|
|
ypixel = packet_get_int();
|
|
pty_change_window_size(ptyfd, row, col, xpixel, ypixel);
|
|
|
|
/* Get tty modes from the packet. */
|
|
tty_parse_modes(ttyfd, &n_bytes);
|
|
packet_integrity_check(plen, 4 + dlen + 4 * 4 + n_bytes, type);
|
|
|
|
/* Indicate that we now have a pty. */
|
|
have_pty = 1;
|
|
|
|
#ifdef USE_PAM
|
|
/* do the pam_open_session since we have the pty */
|
|
do_pam_session(pw->pw_name,ttyname);
|
|
#endif /* USE_PAM */
|
|
|
|
break;
|
|
|
|
case SSH_CMSG_X11_REQUEST_FORWARDING:
|
|
if (!options.x11_forwarding) {
|
|
packet_send_debug("X11 forwarding disabled in server configuration file.");
|
|
goto fail;
|
|
}
|
|
#ifdef XAUTH_PATH
|
|
if (no_x11_forwarding_flag) {
|
|
packet_send_debug("X11 forwarding not permitted for this authentication.");
|
|
goto fail;
|
|
}
|
|
debug("Received request for X11 forwarding with auth spoofing.");
|
|
if (display)
|
|
packet_disconnect("Protocol error: X11 display already set.");
|
|
{
|
|
int proto_len, data_len;
|
|
proto = packet_get_string(&proto_len);
|
|
data = packet_get_string(&data_len);
|
|
packet_integrity_check(plen, 4 + proto_len + 4 + data_len + 4, type);
|
|
}
|
|
if (packet_get_protocol_flags() & SSH_PROTOFLAG_SCREEN_NUMBER)
|
|
screen = packet_get_int();
|
|
else
|
|
screen = 0;
|
|
display = x11_create_display_inet(screen, options.x11_display_offset);
|
|
if (!display)
|
|
goto fail;
|
|
|
|
/* Setup to always have a local .Xauthority. */
|
|
xauthfile = xmalloc(MAXPATHLEN);
|
|
snprintf(xauthfile, MAXPATHLEN, "/tmp/XauthXXXXXX");
|
|
|
|
if ((xauthfd = mkstemp(xauthfile)) != -1) {
|
|
fchown(xauthfd, pw->pw_uid, pw->pw_gid);
|
|
close(xauthfd);
|
|
fatal_add_cleanup(xauthfile_cleanup_proc, NULL);
|
|
} else {
|
|
xfree(xauthfile);
|
|
xauthfile = NULL;
|
|
}
|
|
break;
|
|
#else /* XAUTH_PATH */
|
|
packet_send_debug("No xauth program; cannot forward with spoofing.");
|
|
goto fail;
|
|
#endif /* XAUTH_PATH */
|
|
|
|
case SSH_CMSG_AGENT_REQUEST_FORWARDING:
|
|
if (no_agent_forwarding_flag) {
|
|
debug("Authentication agent forwarding not permitted for this authentication.");
|
|
goto fail;
|
|
}
|
|
debug("Received authentication agent forwarding request.");
|
|
auth_input_request_forwarding(pw);
|
|
break;
|
|
|
|
case SSH_CMSG_PORT_FORWARD_REQUEST:
|
|
if (no_port_forwarding_flag) {
|
|
debug("Port forwarding not permitted for this authentication.");
|
|
goto fail;
|
|
}
|
|
debug("Received TCP/IP port forwarding request.");
|
|
channel_input_port_forward_request(pw->pw_uid == 0);
|
|
break;
|
|
|
|
case SSH_CMSG_MAX_PACKET_SIZE:
|
|
if (packet_set_maxsize(packet_get_int()) < 0)
|
|
goto fail;
|
|
break;
|
|
|
|
case SSH_CMSG_EXEC_SHELL:
|
|
/* Set interactive/non-interactive mode. */
|
|
packet_set_interactive(have_pty || display != NULL,
|
|
options.keepalives);
|
|
|
|
#ifdef USE_PAM
|
|
do_pam_setcred();
|
|
#endif
|
|
if (forced_command != NULL)
|
|
goto do_forced_command;
|
|
debug("Forking shell.");
|
|
packet_integrity_check(plen, 0, type);
|
|
if (have_pty)
|
|
do_exec_pty(NULL, ptyfd, ttyfd, ttyname, pw, term, display, proto, data);
|
|
else
|
|
do_exec_no_pty(NULL, pw, display, proto, data);
|
|
return;
|
|
|
|
case SSH_CMSG_EXEC_CMD:
|
|
/* Set interactive/non-interactive mode. */
|
|
packet_set_interactive(have_pty || display != NULL,
|
|
options.keepalives);
|
|
|
|
#ifdef USE_PAM
|
|
do_pam_setcred();
|
|
#endif
|
|
if (forced_command != NULL)
|
|
goto do_forced_command;
|
|
/* Get command from the packet. */
|
|
{
|
|
int dlen;
|
|
command = packet_get_string(&dlen);
|
|
debug("Executing command '%.500s'", command);
|
|
packet_integrity_check(plen, 4 + dlen, type);
|
|
}
|
|
if (have_pty)
|
|
do_exec_pty(command, ptyfd, ttyfd, ttyname, pw, term, display, proto, data);
|
|
else
|
|
do_exec_no_pty(command, pw, display, proto, data);
|
|
xfree(command);
|
|
return;
|
|
|
|
default:
|
|
/*
|
|
* Any unknown messages in this phase are ignored,
|
|
* and a failure message is returned.
|
|
*/
|
|
log("Unknown packet type received after authentication: %d", type);
|
|
goto fail;
|
|
}
|
|
|
|
/* The request was successfully processed. */
|
|
packet_start(SSH_SMSG_SUCCESS);
|
|
packet_send();
|
|
packet_write_wait();
|
|
|
|
/* Enable compression now that we have replied if appropriate. */
|
|
if (enable_compression_after_reply) {
|
|
enable_compression_after_reply = 0;
|
|
packet_start_compression(compression_level);
|
|
}
|
|
continue;
|
|
|
|
fail:
|
|
/* The request failed. */
|
|
packet_start(SSH_SMSG_FAILURE);
|
|
packet_send();
|
|
packet_write_wait();
|
|
continue;
|
|
|
|
do_forced_command:
|
|
/*
|
|
* There is a forced command specified for this login.
|
|
* Execute it.
|
|
*/
|
|
debug("Executing forced command: %.900s", forced_command);
|
|
if (have_pty)
|
|
do_exec_pty(forced_command, ptyfd, ttyfd, ttyname, pw, term, display, proto, data);
|
|
else
|
|
do_exec_no_pty(forced_command, pw, display, proto, data);
|
|
return;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* This is called to fork and execute a command when we have no tty. This
|
|
* will call do_child from the child, and server_loop from the parent after
|
|
* setting up file descriptors and such.
|
|
*/
|
|
void
|
|
do_exec_no_pty(const char *command, struct passwd * pw,
|
|
const char *display, const char *auth_proto,
|
|
const char *auth_data)
|
|
{
|
|
int pid;
|
|
|
|
#ifdef USE_PIPES
|
|
int pin[2], pout[2], perr[2];
|
|
/* Allocate pipes for communicating with the program. */
|
|
if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0)
|
|
packet_disconnect("Could not create pipes: %.100s",
|
|
strerror(errno));
|
|
#else /* USE_PIPES */
|
|
int inout[2], err[2];
|
|
/* Uses socket pairs to communicate with the program. */
|
|
if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 ||
|
|
socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0)
|
|
packet_disconnect("Could not create socket pairs: %.100s",
|
|
strerror(errno));
|
|
#endif /* USE_PIPES */
|
|
|
|
setproctitle("%s@notty", pw->pw_name);
|
|
|
|
/* Fork the child. */
|
|
if ((pid = fork()) == 0) {
|
|
/* Child. Reinitialize the log since the pid has changed. */
|
|
log_init(av0, options.log_level, options.log_facility, log_stderr);
|
|
|
|
/*
|
|
* Create a new session and process group since the 4.4BSD
|
|
* setlogin() affects the entire process group.
|
|
*/
|
|
if (setsid() < 0)
|
|
error("setsid failed: %.100s", strerror(errno));
|
|
|
|
#ifdef USE_PIPES
|
|
/*
|
|
* Redirect stdin. We close the parent side of the socket
|
|
* pair, and make the child side the standard input.
|
|
*/
|
|
close(pin[1]);
|
|
if (dup2(pin[0], 0) < 0)
|
|
perror("dup2 stdin");
|
|
close(pin[0]);
|
|
|
|
/* Redirect stdout. */
|
|
close(pout[0]);
|
|
if (dup2(pout[1], 1) < 0)
|
|
perror("dup2 stdout");
|
|
close(pout[1]);
|
|
|
|
/* Redirect stderr. */
|
|
close(perr[0]);
|
|
if (dup2(perr[1], 2) < 0)
|
|
perror("dup2 stderr");
|
|
close(perr[1]);
|
|
#else /* USE_PIPES */
|
|
/*
|
|
* Redirect stdin, stdout, and stderr. Stdin and stdout will
|
|
* use the same socket, as some programs (particularly rdist)
|
|
* seem to depend on it.
|
|
*/
|
|
close(inout[1]);
|
|
close(err[1]);
|
|
if (dup2(inout[0], 0) < 0) /* stdin */
|
|
perror("dup2 stdin");
|
|
if (dup2(inout[0], 1) < 0) /* stdout. Note: same socket as stdin. */
|
|
perror("dup2 stdout");
|
|
if (dup2(err[0], 2) < 0) /* stderr */
|
|
perror("dup2 stderr");
|
|
#endif /* USE_PIPES */
|
|
|
|
/* Do processing for the child (exec command etc). */
|
|
do_child(command, pw, NULL, display, auth_proto, auth_data, NULL);
|
|
/* NOTREACHED */
|
|
}
|
|
if (pid < 0)
|
|
packet_disconnect("fork failed: %.100s", strerror(errno));
|
|
#ifdef USE_PIPES
|
|
/* We are the parent. Close the child sides of the pipes. */
|
|
close(pin[0]);
|
|
close(pout[1]);
|
|
close(perr[1]);
|
|
|
|
/* Enter the interactive session. */
|
|
server_loop(pid, pin[1], pout[0], perr[0]);
|
|
/* server_loop has closed pin[1], pout[1], and perr[1]. */
|
|
#else /* USE_PIPES */
|
|
/* We are the parent. Close the child sides of the socket pairs. */
|
|
close(inout[0]);
|
|
close(err[0]);
|
|
|
|
/*
|
|
* Enter the interactive session. Note: server_loop must be able to
|
|
* handle the case that fdin and fdout are the same.
|
|
*/
|
|
server_loop(pid, inout[1], inout[1], err[1]);
|
|
/* server_loop has closed inout[1] and err[1]. */
|
|
#endif /* USE_PIPES */
|
|
}
|
|
|
|
struct pty_cleanup_context {
|
|
const char *ttyname;
|
|
int pid;
|
|
};
|
|
|
|
/*
|
|
* Function to perform cleanup if we get aborted abnormally (e.g., due to a
|
|
* dropped connection).
|
|
*/
|
|
void
|
|
pty_cleanup_proc(void *context)
|
|
{
|
|
struct pty_cleanup_context *cu = context;
|
|
|
|
debug("pty_cleanup_proc called");
|
|
|
|
/* Record that the user has logged out. */
|
|
record_logout(cu->pid, cu->ttyname);
|
|
|
|
/* Release the pseudo-tty. */
|
|
pty_release(cu->ttyname);
|
|
}
|
|
|
|
/*
|
|
* This is called to fork and execute a command when we have a tty. This
|
|
* will call do_child from the child, and server_loop from the parent after
|
|
* setting up file descriptors, controlling tty, updating wtmp, utmp,
|
|
* lastlog, and other such operations.
|
|
*/
|
|
void
|
|
do_exec_pty(const char *command, int ptyfd, int ttyfd,
|
|
const char *ttyname, struct passwd * pw, const char *term,
|
|
const char *display, const char *auth_proto,
|
|
const char *auth_data)
|
|
{
|
|
int pid, fdout;
|
|
const char *hostname;
|
|
time_t last_login_time;
|
|
char buf[100], *time_string;
|
|
FILE *f;
|
|
char line[256];
|
|
struct stat st;
|
|
int quiet_login;
|
|
struct sockaddr_in from;
|
|
int fromlen;
|
|
struct pty_cleanup_context cleanup_context;
|
|
|
|
/* Get remote host name. */
|
|
hostname = get_canonical_hostname();
|
|
|
|
/*
|
|
* Get the time when the user last logged in. Buf will be set to
|
|
* contain the hostname the last login was from.
|
|
*/
|
|
if (!options.use_login) {
|
|
last_login_time = get_last_login_time(pw->pw_uid, pw->pw_name,
|
|
buf, sizeof(buf));
|
|
}
|
|
setproctitle("%s@%s", pw->pw_name, strrchr(ttyname, '/') + 1);
|
|
|
|
/* Fork the child. */
|
|
if ((pid = fork()) == 0) {
|
|
pid = getpid();
|
|
|
|
/* Child. Reinitialize the log because the pid has
|
|
changed. */
|
|
log_init(av0, options.log_level, options.log_facility, log_stderr);
|
|
|
|
/* Close the master side of the pseudo tty. */
|
|
close(ptyfd);
|
|
|
|
/* Make the pseudo tty our controlling tty. */
|
|
pty_make_controlling_tty(&ttyfd, ttyname);
|
|
|
|
/* Redirect stdin from the pseudo tty. */
|
|
if (dup2(ttyfd, fileno(stdin)) < 0)
|
|
error("dup2 stdin failed: %.100s", strerror(errno));
|
|
|
|
/* Redirect stdout to the pseudo tty. */
|
|
if (dup2(ttyfd, fileno(stdout)) < 0)
|
|
error("dup2 stdin failed: %.100s", strerror(errno));
|
|
|
|
/* Redirect stderr to the pseudo tty. */
|
|
if (dup2(ttyfd, fileno(stderr)) < 0)
|
|
error("dup2 stdin failed: %.100s", strerror(errno));
|
|
|
|
/* Close the extra descriptor for the pseudo tty. */
|
|
close(ttyfd);
|
|
|
|
/*
|
|
* Get IP address of client. This is needed because we want
|
|
* to record where the user logged in from. If the
|
|
* connection is not a socket, let the ip address be 0.0.0.0.
|
|
*/
|
|
memset(&from, 0, sizeof(from));
|
|
if (packet_get_connection_in() == packet_get_connection_out()) {
|
|
fromlen = sizeof(from);
|
|
if (getpeername(packet_get_connection_in(),
|
|
(struct sockaddr *) & from, &fromlen) < 0) {
|
|
debug("getpeername: %.100s", strerror(errno));
|
|
fatal_cleanup();
|
|
}
|
|
}
|
|
/* Record that there was a login on that terminal. */
|
|
record_login(pid, ttyname, pw->pw_name, pw->pw_uid, hostname,
|
|
&from);
|
|
|
|
/* Check if .hushlogin exists. */
|
|
snprintf(line, sizeof line, "%.200s/.hushlogin", pw->pw_dir);
|
|
quiet_login = stat(line, &st) >= 0;
|
|
|
|
#ifdef USE_PAM
|
|
/* output the results of the pamconv() */
|
|
if (!quiet_login && pamconv_msg != NULL)
|
|
fprintf(stderr, pamconv_msg);
|
|
#endif
|
|
|
|
/*
|
|
* If the user has logged in before, display the time of last
|
|
* login. However, don't display anything extra if a command
|
|
* has been specified (so that ssh can be used to execute
|
|
* commands on a remote machine without users knowing they
|
|
* are going to another machine). Login(1) will do this for
|
|
* us as well, so check if login(1) is used
|
|
*/
|
|
if (command == NULL && last_login_time != 0 && !quiet_login &&
|
|
!options.use_login) {
|
|
/* Convert the date to a string. */
|
|
time_string = ctime(&last_login_time);
|
|
/* Remove the trailing newline. */
|
|
if (strchr(time_string, '\n'))
|
|
*strchr(time_string, '\n') = 0;
|
|
/* Display the last login time. Host if displayed
|
|
if known. */
|
|
if (strcmp(buf, "") == 0)
|
|
printf("Last login: %s\r\n", time_string);
|
|
else
|
|
printf("Last login: %s from %s\r\n", time_string, buf);
|
|
}
|
|
/*
|
|
* Print /etc/motd unless a command was specified or printing
|
|
* it was disabled in server options or login(1) will be
|
|
* used. Note that some machines appear to print it in
|
|
* /etc/profile or similar.
|
|
*/
|
|
if (command == NULL && options.print_motd && !quiet_login &&
|
|
!options.use_login) {
|
|
/* Print /etc/motd if it exists. */
|
|
f = fopen("/etc/motd", "r");
|
|
if (f) {
|
|
while (fgets(line, sizeof(line), f))
|
|
fputs(line, stdout);
|
|
fclose(f);
|
|
}
|
|
}
|
|
/* Do common processing for the child, such as execing the command. */
|
|
do_child(command, pw, term, display, auth_proto, auth_data, ttyname);
|
|
/* NOTREACHED */
|
|
}
|
|
if (pid < 0)
|
|
packet_disconnect("fork failed: %.100s", strerror(errno));
|
|
/* Parent. Close the slave side of the pseudo tty. */
|
|
close(ttyfd);
|
|
|
|
/*
|
|
* Create another descriptor of the pty master side for use as the
|
|
* standard input. We could use the original descriptor, but this
|
|
* simplifies code in server_loop. The descriptor is bidirectional.
|
|
*/
|
|
fdout = dup(ptyfd);
|
|
if (fdout < 0)
|
|
packet_disconnect("dup failed: %.100s", strerror(errno));
|
|
|
|
/*
|
|
* Add a cleanup function to clear the utmp entry and record logout
|
|
* time in case we call fatal() (e.g., the connection gets closed).
|
|
*/
|
|
cleanup_context.pid = pid;
|
|
cleanup_context.ttyname = ttyname;
|
|
fatal_add_cleanup(pty_cleanup_proc, (void *) &cleanup_context);
|
|
|
|
/* Enter interactive session. */
|
|
server_loop(pid, ptyfd, fdout, -1);
|
|
/* server_loop has not closed ptyfd and fdout. */
|
|
|
|
/* Cancel the cleanup function. */
|
|
fatal_remove_cleanup(pty_cleanup_proc, (void *) &cleanup_context);
|
|
|
|
/* Record that the user has logged out. */
|
|
record_logout(pid, ttyname);
|
|
|
|
/* Release the pseudo-tty. */
|
|
pty_release(ttyname);
|
|
|
|
/*
|
|
* Close the server side of the socket pairs. We must do this after
|
|
* the pty cleanup, so that another process doesn't get this pty
|
|
* while we're still cleaning up.
|
|
*/
|
|
close(ptyfd);
|
|
close(fdout);
|
|
}
|
|
|
|
/*
|
|
* Sets the value of the given variable in the environment. If the variable
|
|
* already exists, its value is overriden.
|
|
*/
|
|
void
|
|
child_set_env(char ***envp, unsigned int *envsizep, const char *name,
|
|
const char *value)
|
|
{
|
|
unsigned int i, namelen;
|
|
char **env;
|
|
|
|
/*
|
|
* Find the slot where the value should be stored. If the variable
|
|
* already exists, we reuse the slot; otherwise we append a new slot
|
|
* at the end of the array, expanding if necessary.
|
|
*/
|
|
env = *envp;
|
|
namelen = strlen(name);
|
|
for (i = 0; env[i]; i++)
|
|
if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=')
|
|
break;
|
|
if (env[i]) {
|
|
/* Reuse the slot. */
|
|
xfree(env[i]);
|
|
} else {
|
|
/* New variable. Expand if necessary. */
|
|
if (i >= (*envsizep) - 1) {
|
|
(*envsizep) += 50;
|
|
env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *));
|
|
}
|
|
/* Need to set the NULL pointer at end of array beyond the new slot. */
|
|
env[i + 1] = NULL;
|
|
}
|
|
|
|
/* Allocate space and format the variable in the appropriate slot. */
|
|
env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1);
|
|
snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value);
|
|
}
|
|
|
|
/*
|
|
* Reads environment variables from the given file and adds/overrides them
|
|
* into the environment. If the file does not exist, this does nothing.
|
|
* Otherwise, it must consist of empty lines, comments (line starts with '#')
|
|
* and assignments of the form name=value. No other forms are allowed.
|
|
*/
|
|
void
|
|
read_environment_file(char ***env, unsigned int *envsize,
|
|
const char *filename)
|
|
{
|
|
FILE *f;
|
|
char buf[4096];
|
|
char *cp, *value;
|
|
|
|
f = fopen(filename, "r");
|
|
if (!f)
|
|
return;
|
|
|
|
while (fgets(buf, sizeof(buf), f)) {
|
|
for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
|
|
;
|
|
if (!*cp || *cp == '#' || *cp == '\n')
|
|
continue;
|
|
if (strchr(cp, '\n'))
|
|
*strchr(cp, '\n') = '\0';
|
|
value = strchr(cp, '=');
|
|
if (value == NULL) {
|
|
fprintf(stderr, "Bad line in %.100s: %.200s\n", filename, buf);
|
|
continue;
|
|
}
|
|
/* Replace the equals sign by nul, and advance value to the value string. */
|
|
*value = '\0';
|
|
value++;
|
|
child_set_env(env, envsize, cp, value);
|
|
}
|
|
fclose(f);
|
|
}
|
|
|
|
/*
|
|
* Performs common processing for the child, such as setting up the
|
|
* environment, closing extra file descriptors, setting the user and group
|
|
* ids, and executing the command or shell.
|
|
*/
|
|
void
|
|
do_child(const char *command, struct passwd * pw, const char *term,
|
|
const char *display, const char *auth_proto,
|
|
const char *auth_data, const char *ttyname)
|
|
{
|
|
const char *shell, *cp = NULL;
|
|
char buf[256];
|
|
FILE *f;
|
|
unsigned int envsize, i;
|
|
char **env;
|
|
extern char **environ;
|
|
struct stat st;
|
|
char *argv[10];
|
|
|
|
#ifndef USE_PAM /* pam_nologin handles this */
|
|
/* Check /etc/nologin. */
|
|
f = fopen("/etc/nologin", "r");
|
|
if (f) {
|
|
/* /etc/nologin exists. Print its contents and exit. */
|
|
while (fgets(buf, sizeof(buf), f))
|
|
fputs(buf, stderr);
|
|
fclose(f);
|
|
if (pw->pw_uid != 0)
|
|
exit(254);
|
|
}
|
|
#endif /* USE_PAM */
|
|
|
|
#ifdef HAVE_SETLOGIN
|
|
/* Set login name in the kernel. */
|
|
if (setlogin(pw->pw_name) < 0)
|
|
error("setlogin failed: %s", strerror(errno));
|
|
#endif /* HAVE_SETLOGIN */
|
|
|
|
/* Set uid, gid, and groups. */
|
|
/* Login(1) does this as well, and it needs uid 0 for the "-h"
|
|
switch, so we let login(1) to this for us. */
|
|
if (!options.use_login) {
|
|
if (getuid() == 0 || geteuid() == 0) {
|
|
if (setgid(pw->pw_gid) < 0) {
|
|
perror("setgid");
|
|
exit(1);
|
|
}
|
|
/* Initialize the group list. */
|
|
if (initgroups(pw->pw_name, pw->pw_gid) < 0) {
|
|
perror("initgroups");
|
|
exit(1);
|
|
}
|
|
endgrent();
|
|
|
|
/* Permanently switch to the desired uid. */
|
|
permanently_set_uid(pw->pw_uid);
|
|
}
|
|
if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid)
|
|
fatal("Failed to set uids to %d.", (int) pw->pw_uid);
|
|
}
|
|
/*
|
|
* Get the shell from the password data. An empty shell field is
|
|
* legal, and means /bin/sh.
|
|
*/
|
|
shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell;
|
|
|
|
#ifdef AFS
|
|
/* Try to get AFS tokens for the local cell. */
|
|
if (k_hasafs()) {
|
|
char cell[64];
|
|
|
|
if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0)
|
|
krb_afslog(cell, 0);
|
|
|
|
krb_afslog(0, 0);
|
|
}
|
|
#endif /* AFS */
|
|
|
|
/* Initialize the environment. */
|
|
envsize = 100;
|
|
env = xmalloc(envsize * sizeof(char *));
|
|
env[0] = NULL;
|
|
|
|
if (!options.use_login) {
|
|
/* Set basic environment. */
|
|
child_set_env(&env, &envsize, "USER", pw->pw_name);
|
|
child_set_env(&env, &envsize, "LOGNAME", pw->pw_name);
|
|
child_set_env(&env, &envsize, "HOME", pw->pw_dir);
|
|
child_set_env(&env, &envsize, "PATH", _PATH_STDPATH);
|
|
|
|
snprintf(buf, sizeof buf, "%.200s/%.50s",
|
|
_PATH_MAILDIR, pw->pw_name);
|
|
child_set_env(&env, &envsize, "MAIL", buf);
|
|
|
|
/* Normal systems set SHELL by default. */
|
|
child_set_env(&env, &envsize, "SHELL", shell);
|
|
}
|
|
if (getenv("TZ"))
|
|
child_set_env(&env, &envsize, "TZ", getenv("TZ"));
|
|
|
|
/* Set custom environment options from RSA authentication. */
|
|
while (custom_environment) {
|
|
struct envstring *ce = custom_environment;
|
|
char *s = ce->s;
|
|
int i;
|
|
for (i = 0; s[i] != '=' && s[i]; i++);
|
|
if (s[i] == '=') {
|
|
s[i] = 0;
|
|
child_set_env(&env, &envsize, s, s + i + 1);
|
|
}
|
|
custom_environment = ce->next;
|
|
xfree(ce->s);
|
|
xfree(ce);
|
|
}
|
|
|
|
snprintf(buf, sizeof buf, "%.50s %d %d",
|
|
get_remote_ipaddr(), get_remote_port(), options.port);
|
|
child_set_env(&env, &envsize, "SSH_CLIENT", buf);
|
|
|
|
if (ttyname)
|
|
child_set_env(&env, &envsize, "SSH_TTY", ttyname);
|
|
if (term)
|
|
child_set_env(&env, &envsize, "TERM", term);
|
|
if (display)
|
|
child_set_env(&env, &envsize, "DISPLAY", display);
|
|
|
|
#ifdef KRB4
|
|
{
|
|
extern char *ticket;
|
|
|
|
if (ticket)
|
|
child_set_env(&env, &envsize, "KRBTKFILE", ticket);
|
|
}
|
|
#endif /* KRB4 */
|
|
|
|
#ifdef USE_PAM
|
|
/* Pull in any environment variables that may have been set by PAM. */
|
|
{
|
|
char *equals, var_name[512], var_val[512];
|
|
char **pam_env = pam_getenvlist((pam_handle_t *)pamh);
|
|
int i;
|
|
for(i = 0; pam_env && pam_env[i]; i++) {
|
|
equals = strstr(pam_env[i], "=");
|
|
if ((strlen(pam_env[i]) < (sizeof(var_name) - 1)) && (equals != NULL))
|
|
{
|
|
debug("PAM environment: %s=%s", var_name, var_val);
|
|
memset(var_name, '\0', sizeof(var_name));
|
|
memset(var_val, '\0', sizeof(var_val));
|
|
strncpy(var_name, pam_env[i], equals - pam_env[i]);
|
|
strcpy(var_val, equals + 1);
|
|
child_set_env(&env, &envsize, var_name, var_val);
|
|
}
|
|
}
|
|
}
|
|
#endif /* USE_PAM */
|
|
|
|
if (xauthfile)
|
|
child_set_env(&env, &envsize, "XAUTHORITY", xauthfile);
|
|
|
|
if (auth_get_socket_name() != NULL)
|
|
child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME,
|
|
auth_get_socket_name());
|
|
|
|
/* read $HOME/.ssh/environment. */
|
|
if (!options.use_login) {
|
|
snprintf(buf, sizeof buf, "%.200s/.ssh/environment", pw->pw_dir);
|
|
read_environment_file(&env, &envsize, buf);
|
|
}
|
|
if (debug_flag) {
|
|
/* dump the environment */
|
|
fprintf(stderr, "Environment:\n");
|
|
for (i = 0; env[i]; i++)
|
|
fprintf(stderr, " %.200s\n", env[i]);
|
|
}
|
|
/*
|
|
* Close the connection descriptors; note that this is the child, and
|
|
* the server will still have the socket open, and it is important
|
|
* that we do not shutdown it. Note that the descriptors cannot be
|
|
* closed before building the environment, as we call
|
|
* get_remote_ipaddr there.
|
|
*/
|
|
if (packet_get_connection_in() == packet_get_connection_out())
|
|
close(packet_get_connection_in());
|
|
else {
|
|
close(packet_get_connection_in());
|
|
close(packet_get_connection_out());
|
|
}
|
|
/*
|
|
* Close all descriptors related to channels. They will still remain
|
|
* open in the parent.
|
|
*/
|
|
/* XXX better use close-on-exec? -markus */
|
|
channel_close_all();
|
|
|
|
/*
|
|
* Close any extra file descriptors. Note that there may still be
|
|
* descriptors left by system functions. They will be closed later.
|
|
*/
|
|
endpwent();
|
|
endhostent();
|
|
|
|
/*
|
|
* Close any extra open file descriptors so that we don\'t have them
|
|
* hanging around in clients. Note that we want to do this after
|
|
* initgroups, because at least on Solaris 2.3 it leaves file
|
|
* descriptors open.
|
|
*/
|
|
for (i = 3; i < 64; i++)
|
|
close(i);
|
|
|
|
/* Change current directory to the user\'s home directory. */
|
|
if (chdir(pw->pw_dir) < 0)
|
|
fprintf(stderr, "Could not chdir to home directory %s: %s\n",
|
|
pw->pw_dir, strerror(errno));
|
|
|
|
/*
|
|
* Must take new environment into use so that .ssh/rc, /etc/sshrc and
|
|
* xauth are run in the proper environment.
|
|
*/
|
|
environ = env;
|
|
|
|
/*
|
|
* Run $HOME/.ssh/rc, /etc/sshrc, or xauth (whichever is found first
|
|
* in this order).
|
|
*/
|
|
if (!options.use_login) {
|
|
if (stat(SSH_USER_RC, &st) >= 0) {
|
|
if (debug_flag)
|
|
fprintf(stderr, "Running /bin/sh %s\n", SSH_USER_RC);
|
|
|
|
f = popen("/bin/sh " SSH_USER_RC, "w");
|
|
if (f) {
|
|
if (auth_proto != NULL && auth_data != NULL)
|
|
fprintf(f, "%s %s\n", auth_proto, auth_data);
|
|
pclose(f);
|
|
} else
|
|
fprintf(stderr, "Could not run %s\n", SSH_USER_RC);
|
|
} else if (stat(SSH_SYSTEM_RC, &st) >= 0) {
|
|
if (debug_flag)
|
|
fprintf(stderr, "Running /bin/sh %s\n", SSH_SYSTEM_RC);
|
|
|
|
f = popen("/bin/sh " SSH_SYSTEM_RC, "w");
|
|
if (f) {
|
|
if (auth_proto != NULL && auth_data != NULL)
|
|
fprintf(f, "%s %s\n", auth_proto, auth_data);
|
|
pclose(f);
|
|
} else
|
|
fprintf(stderr, "Could not run %s\n", SSH_SYSTEM_RC);
|
|
}
|
|
#ifdef XAUTH_PATH
|
|
else {
|
|
/* Add authority data to .Xauthority if appropriate. */
|
|
if (auth_proto != NULL && auth_data != NULL) {
|
|
if (debug_flag)
|
|
fprintf(stderr, "Running %.100s add %.100s %.100s %.100s\n",
|
|
XAUTH_PATH, display, auth_proto, auth_data);
|
|
|
|
f = popen(XAUTH_PATH " -q -", "w");
|
|
if (f) {
|
|
fprintf(f, "add %s %s %s\n", display, auth_proto, auth_data);
|
|
fclose(f);
|
|
} else
|
|
fprintf(stderr, "Could not run %s -q -\n", XAUTH_PATH);
|
|
}
|
|
}
|
|
#endif /* XAUTH_PATH */
|
|
|
|
/* Get the last component of the shell name. */
|
|
cp = strrchr(shell, '/');
|
|
if (cp)
|
|
cp++;
|
|
else
|
|
cp = shell;
|
|
}
|
|
/*
|
|
* If we have no command, execute the shell. In this case, the shell
|
|
* name to be passed in argv[0] is preceded by '-' to indicate that
|
|
* this is a login shell.
|
|
*/
|
|
if (!command) {
|
|
if (!options.use_login) {
|
|
char buf[256];
|
|
|
|
/*
|
|
* Check for mail if we have a tty and it was enabled
|
|
* in server options.
|
|
*/
|
|
if (ttyname && options.check_mail) {
|
|
char *mailbox;
|
|
struct stat mailstat;
|
|
mailbox = getenv("MAIL");
|
|
if (mailbox != NULL) {
|
|
if (stat(mailbox, &mailstat) != 0 || mailstat.st_size == 0)
|
|
printf("No mail.\n");
|
|
else if (mailstat.st_mtime < mailstat.st_atime)
|
|
printf("You have mail.\n");
|
|
else
|
|
printf("You have new mail.\n");
|
|
}
|
|
}
|
|
/* Start the shell. Set initial character to '-'. */
|
|
buf[0] = '-';
|
|
strncpy(buf + 1, cp, sizeof(buf) - 1);
|
|
buf[sizeof(buf) - 1] = 0;
|
|
|
|
/* Execute the shell. */
|
|
argv[0] = buf;
|
|
argv[1] = NULL;
|
|
execve(shell, argv, env);
|
|
|
|
/* Executing the shell failed. */
|
|
perror(shell);
|
|
exit(1);
|
|
|
|
} else {
|
|
/* Launch login(1). */
|
|
|
|
execl(LOGIN_PROGRAM, "login", "-h", get_remote_ipaddr(),
|
|
"-p", "-f", "--", pw->pw_name, NULL);
|
|
|
|
/* Login couldn't be executed, die. */
|
|
|
|
perror("login");
|
|
exit(1);
|
|
}
|
|
}
|
|
/*
|
|
* Execute the command using the user's shell. This uses the -c
|
|
* option to execute the command.
|
|
*/
|
|
argv[0] = (char *) cp;
|
|
argv[1] = "-c";
|
|
argv[2] = (char *) command;
|
|
argv[3] = NULL;
|
|
execve(shell, argv, env);
|
|
perror(shell);
|
|
exit(1);
|
|
}
|