2000-02-24 14:29:47 +00:00
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/*
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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: Sat Mar 18 22:15:47 1995 ylo
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* Code to connect to a remote host, and to perform the client side of the
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* login (authentication) dialog.
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2000-02-24 15:29:42 +00:00
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*
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* $FreeBSD$
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2000-02-24 14:29:47 +00:00
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*/
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#include "includes.h"
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RCSID("$OpenBSD: sshconnect.c,v 1.56 2000/02/18 08:50:33 markus Exp $");
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2000-02-25 01:53:12 +00:00
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#include <openssl/bn.h>
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2000-02-24 14:29:47 +00:00
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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 "packet.h"
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#include "authfd.h"
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#include "cipher.h"
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#include "mpaux.h"
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#include "uidswap.h"
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#include "compat.h"
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#include "readconf.h"
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#include "fingerprint.h"
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2000-02-25 01:53:12 +00:00
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#include <openssl/md5.h>
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2000-02-24 14:29:47 +00:00
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/* Session id for the current session. */
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unsigned char session_id[16];
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/* authentications supported by server */
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unsigned int supported_authentications;
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extern Options options;
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extern char *__progname;
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/*
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* Connect to the given ssh server using a proxy command.
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*/
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int
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ssh_proxy_connect(const char *host, u_short port, uid_t original_real_uid,
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const char *proxy_command)
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{
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Buffer command;
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const char *cp;
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char *command_string;
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int pin[2], pout[2];
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int pid;
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char strport[NI_MAXSERV];
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/* Convert the port number into a string. */
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snprintf(strport, sizeof strport, "%hu", port);
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/* Build the final command string in the buffer by making the
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appropriate substitutions to the given proxy command. */
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buffer_init(&command);
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for (cp = proxy_command; *cp; cp++) {
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if (cp[0] == '%' && cp[1] == '%') {
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buffer_append(&command, "%", 1);
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cp++;
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continue;
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}
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if (cp[0] == '%' && cp[1] == 'h') {
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buffer_append(&command, host, strlen(host));
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cp++;
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continue;
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}
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if (cp[0] == '%' && cp[1] == 'p') {
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buffer_append(&command, strport, strlen(strport));
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cp++;
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continue;
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}
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buffer_append(&command, cp, 1);
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}
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buffer_append(&command, "\0", 1);
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/* Get the final command string. */
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command_string = buffer_ptr(&command);
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/* Create pipes for communicating with the proxy. */
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if (pipe(pin) < 0 || pipe(pout) < 0)
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fatal("Could not create pipes to communicate with the proxy: %.100s",
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strerror(errno));
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debug("Executing proxy command: %.500s", command_string);
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/* Fork and execute the proxy command. */
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if ((pid = fork()) == 0) {
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char *argv[10];
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/* Child. Permanently give up superuser privileges. */
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permanently_set_uid(original_real_uid);
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/* Redirect stdin and stdout. */
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close(pin[1]);
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if (pin[0] != 0) {
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if (dup2(pin[0], 0) < 0)
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perror("dup2 stdin");
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close(pin[0]);
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}
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close(pout[0]);
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if (dup2(pout[1], 1) < 0)
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perror("dup2 stdout");
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/* Cannot be 1 because pin allocated two descriptors. */
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close(pout[1]);
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/* Stderr is left as it is so that error messages get
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printed on the user's terminal. */
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argv[0] = "/bin/sh";
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argv[1] = "-c";
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argv[2] = command_string;
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argv[3] = NULL;
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/* Execute the proxy command. Note that we gave up any
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extra privileges above. */
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execv("/bin/sh", argv);
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perror("/bin/sh");
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exit(1);
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}
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/* Parent. */
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if (pid < 0)
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fatal("fork failed: %.100s", strerror(errno));
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/* Close child side of the descriptors. */
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close(pin[0]);
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close(pout[1]);
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/* Free the command name. */
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buffer_free(&command);
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/* Set the connection file descriptors. */
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packet_set_connection(pout[0], pin[1]);
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return 1;
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}
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/*
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* Creates a (possibly privileged) socket for use as the ssh connection.
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*/
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int
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ssh_create_socket(uid_t original_real_uid, int privileged, int family)
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{
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int sock;
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/*
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* If we are running as root and want to connect to a privileged
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* port, bind our own socket to a privileged port.
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*/
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if (privileged) {
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int p = IPPORT_RESERVED - 1;
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sock = rresvport_af(&p, family);
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if (sock < 0)
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error("rresvport: af=%d %.100s", family, strerror(errno));
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else
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debug("Allocated local port %d.", p);
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} else {
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/*
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* Just create an ordinary socket on arbitrary port. We use
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* the user's uid to create the socket.
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*/
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temporarily_use_uid(original_real_uid);
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sock = socket(family, SOCK_STREAM, 0);
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if (sock < 0)
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error("socket: %.100s", strerror(errno));
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restore_uid();
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}
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return sock;
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}
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/*
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* Opens a TCP/IP connection to the remote server on the given host.
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* The address of the remote host will be returned in hostaddr.
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* If port is 0, the default port will be used. If anonymous is zero,
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* a privileged port will be allocated to make the connection.
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* This requires super-user privileges if anonymous is false.
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* Connection_attempts specifies the maximum number of tries (one per
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* second). If proxy_command is non-NULL, it specifies the command (with %h
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* and %p substituted for host and port, respectively) to use to contact
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* the daemon.
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*/
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int
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ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
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u_short port, int connection_attempts,
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int anonymous, uid_t original_real_uid,
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const char *proxy_command)
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{
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int sock = -1, attempt;
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struct servent *sp;
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struct addrinfo hints, *ai, *aitop;
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char ntop[NI_MAXHOST], strport[NI_MAXSERV];
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int gaierr;
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struct linger linger;
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debug("ssh_connect: getuid %d geteuid %d anon %d",
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(int) getuid(), (int) geteuid(), anonymous);
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/* Get default port if port has not been set. */
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if (port == 0) {
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sp = getservbyname(SSH_SERVICE_NAME, "tcp");
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if (sp)
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port = ntohs(sp->s_port);
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else
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port = SSH_DEFAULT_PORT;
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}
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/* If a proxy command is given, connect using it. */
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if (proxy_command != NULL)
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return ssh_proxy_connect(host, port, original_real_uid, proxy_command);
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/* No proxy command. */
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memset(&hints, 0, sizeof(hints));
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hints.ai_family = IPv4or6;
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hints.ai_socktype = SOCK_STREAM;
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snprintf(strport, sizeof strport, "%d", port);
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if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
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fatal("%s: %.100s: %s", __progname, host,
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gai_strerror(gaierr));
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/*
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* Try to connect several times. On some machines, the first time
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* will sometimes fail. In general socket code appears to behave
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* quite magically on many machines.
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*/
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for (attempt = 0; attempt < connection_attempts; attempt++) {
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if (attempt > 0)
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debug("Trying again...");
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/* Loop through addresses for this host, and try each one in
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sequence until the connection succeeds. */
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for (ai = aitop; ai; ai = ai->ai_next) {
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if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
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continue;
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if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
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ntop, sizeof(ntop), strport, sizeof(strport),
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NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
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error("ssh_connect: getnameinfo failed");
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continue;
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}
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debug("Connecting to %.200s [%.100s] port %s.",
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host, ntop, strport);
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/* Create a socket for connecting. */
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sock = ssh_create_socket(original_real_uid,
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!anonymous && geteuid() == 0 && port < IPPORT_RESERVED,
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ai->ai_family);
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if (sock < 0)
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continue;
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/* Connect to the host. We use the user's uid in the
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* hope that it will help with tcp_wrappers showing
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* the remote uid as root.
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*/
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temporarily_use_uid(original_real_uid);
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if (connect(sock, ai->ai_addr, ai->ai_addrlen) >= 0) {
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/* Successful connection. */
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memcpy(hostaddr, ai->ai_addr, sizeof(*hostaddr));
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restore_uid();
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break;
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} else {
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debug("connect: %.100s", strerror(errno));
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restore_uid();
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/*
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* Close the failed socket; there appear to
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* be some problems when reusing a socket for
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* which connect() has already returned an
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* error.
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*/
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shutdown(sock, SHUT_RDWR);
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close(sock);
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}
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}
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if (ai)
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break; /* Successful connection. */
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/* Sleep a moment before retrying. */
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sleep(1);
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}
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freeaddrinfo(aitop);
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/* Return failure if we didn't get a successful connection. */
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if (attempt >= connection_attempts)
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return 0;
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debug("Connection established.");
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/*
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* Set socket options. We would like the socket to disappear as soon
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* as it has been closed for whatever reason.
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*/
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/* setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */
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linger.l_onoff = 1;
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linger.l_linger = 5;
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setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger));
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/* Set the connection. */
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packet_set_connection(sock, sock);
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return 1;
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}
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/*
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* Checks if the user has an authentication agent, and if so, tries to
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* authenticate using the agent.
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*/
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int
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try_agent_authentication()
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{
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int status, type;
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char *comment;
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AuthenticationConnection *auth;
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unsigned char response[16];
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unsigned int i;
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BIGNUM *e, *n, *challenge;
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/* Get connection to the agent. */
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auth = ssh_get_authentication_connection();
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if (!auth)
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return 0;
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e = BN_new();
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n = BN_new();
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challenge = BN_new();
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/* Loop through identities served by the agent. */
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for (status = ssh_get_first_identity(auth, e, n, &comment);
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status;
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status = ssh_get_next_identity(auth, e, n, &comment)) {
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int plen, clen;
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/* Try this identity. */
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debug("Trying RSA authentication via agent with '%.100s'", comment);
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xfree(comment);
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/* Tell the server that we are willing to authenticate using this key. */
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packet_start(SSH_CMSG_AUTH_RSA);
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packet_put_bignum(n);
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packet_send();
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packet_write_wait();
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/* Wait for server's response. */
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type = packet_read(&plen);
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/* The server sends failure if it doesn\'t like our key or
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does not support RSA authentication. */
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if (type == SSH_SMSG_FAILURE) {
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debug("Server refused our key.");
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continue;
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}
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/* Otherwise it should have sent a challenge. */
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if (type != SSH_SMSG_AUTH_RSA_CHALLENGE)
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packet_disconnect("Protocol error during RSA authentication: %d",
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type);
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packet_get_bignum(challenge, &clen);
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packet_integrity_check(plen, clen, type);
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debug("Received RSA challenge from server.");
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/* Ask the agent to decrypt the challenge. */
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if (!ssh_decrypt_challenge(auth, e, n, challenge,
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session_id, 1, response)) {
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/* The agent failed to authenticate this identifier although it
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advertised it supports this. Just return a wrong value. */
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log("Authentication agent failed to decrypt challenge.");
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memset(response, 0, sizeof(response));
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}
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debug("Sending response to RSA challenge.");
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/* Send the decrypted challenge back to the server. */
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packet_start(SSH_CMSG_AUTH_RSA_RESPONSE);
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for (i = 0; i < 16; i++)
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packet_put_char(response[i]);
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packet_send();
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packet_write_wait();
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|
|
/* Wait for response from the server. */
|
|
|
|
type = packet_read(&plen);
|
|
|
|
|
|
|
|
/* The server returns success if it accepted the authentication. */
|
|
|
|
if (type == SSH_SMSG_SUCCESS) {
|
|
|
|
debug("RSA authentication accepted by server.");
|
|
|
|
BN_clear_free(e);
|
|
|
|
BN_clear_free(n);
|
|
|
|
BN_clear_free(challenge);
|
|
|
|
return 1;
|
|
|
|
}
|
|
|
|
/* Otherwise it should return failure. */
|
|
|
|
if (type != SSH_SMSG_FAILURE)
|
|
|
|
packet_disconnect("Protocol error waiting RSA auth response: %d",
|
|
|
|
type);
|
|
|
|
}
|
|
|
|
|
|
|
|
BN_clear_free(e);
|
|
|
|
BN_clear_free(n);
|
|
|
|
BN_clear_free(challenge);
|
|
|
|
|
|
|
|
debug("RSA authentication using agent refused.");
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Computes the proper response to a RSA challenge, and sends the response to
|
|
|
|
* the server.
|
|
|
|
*/
|
|
|
|
void
|
|
|
|
respond_to_rsa_challenge(BIGNUM * challenge, RSA * prv)
|
|
|
|
{
|
|
|
|
unsigned char buf[32], response[16];
|
|
|
|
MD5_CTX md;
|
|
|
|
int i, len;
|
|
|
|
|
|
|
|
/* Decrypt the challenge using the private key. */
|
|
|
|
rsa_private_decrypt(challenge, challenge, prv);
|
|
|
|
|
|
|
|
/* Compute the response. */
|
|
|
|
/* The response is MD5 of decrypted challenge plus session id. */
|
|
|
|
len = BN_num_bytes(challenge);
|
|
|
|
if (len <= 0 || len > sizeof(buf))
|
|
|
|
packet_disconnect("respond_to_rsa_challenge: bad challenge length %d",
|
|
|
|
len);
|
|
|
|
|
|
|
|
memset(buf, 0, sizeof(buf));
|
|
|
|
BN_bn2bin(challenge, buf + sizeof(buf) - len);
|
|
|
|
MD5_Init(&md);
|
|
|
|
MD5_Update(&md, buf, 32);
|
|
|
|
MD5_Update(&md, session_id, 16);
|
|
|
|
MD5_Final(response, &md);
|
|
|
|
|
|
|
|
debug("Sending response to host key RSA challenge.");
|
|
|
|
|
|
|
|
/* Send the response back to the server. */
|
|
|
|
packet_start(SSH_CMSG_AUTH_RSA_RESPONSE);
|
|
|
|
for (i = 0; i < 16; i++)
|
|
|
|
packet_put_char(response[i]);
|
|
|
|
packet_send();
|
|
|
|
packet_write_wait();
|
|
|
|
|
|
|
|
memset(buf, 0, sizeof(buf));
|
|
|
|
memset(response, 0, sizeof(response));
|
|
|
|
memset(&md, 0, sizeof(md));
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Checks if the user has authentication file, and if so, tries to authenticate
|
|
|
|
* the user using it.
|
|
|
|
*/
|
|
|
|
int
|
|
|
|
try_rsa_authentication(const char *authfile)
|
|
|
|
{
|
|
|
|
BIGNUM *challenge;
|
|
|
|
RSA *private_key;
|
|
|
|
RSA *public_key;
|
|
|
|
char *passphrase, *comment;
|
|
|
|
int type, i;
|
|
|
|
int plen, clen;
|
|
|
|
|
|
|
|
/* Try to load identification for the authentication key. */
|
|
|
|
public_key = RSA_new();
|
|
|
|
if (!load_public_key(authfile, public_key, &comment)) {
|
|
|
|
RSA_free(public_key);
|
|
|
|
/* Could not load it. Fail. */
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
debug("Trying RSA authentication with key '%.100s'", comment);
|
|
|
|
|
|
|
|
/* Tell the server that we are willing to authenticate using this key. */
|
|
|
|
packet_start(SSH_CMSG_AUTH_RSA);
|
|
|
|
packet_put_bignum(public_key->n);
|
|
|
|
packet_send();
|
|
|
|
packet_write_wait();
|
|
|
|
|
|
|
|
/* We no longer need the public key. */
|
|
|
|
RSA_free(public_key);
|
|
|
|
|
|
|
|
/* Wait for server's response. */
|
|
|
|
type = packet_read(&plen);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* The server responds with failure if it doesn\'t like our key or
|
|
|
|
* doesn\'t support RSA authentication.
|
|
|
|
*/
|
|
|
|
if (type == SSH_SMSG_FAILURE) {
|
|
|
|
debug("Server refused our key.");
|
|
|
|
xfree(comment);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
/* Otherwise, the server should respond with a challenge. */
|
|
|
|
if (type != SSH_SMSG_AUTH_RSA_CHALLENGE)
|
|
|
|
packet_disconnect("Protocol error during RSA authentication: %d", type);
|
|
|
|
|
|
|
|
/* Get the challenge from the packet. */
|
|
|
|
challenge = BN_new();
|
|
|
|
packet_get_bignum(challenge, &clen);
|
|
|
|
|
|
|
|
packet_integrity_check(plen, clen, type);
|
|
|
|
|
|
|
|
debug("Received RSA challenge from server.");
|
|
|
|
|
|
|
|
private_key = RSA_new();
|
|
|
|
/*
|
|
|
|
* Load the private key. Try first with empty passphrase; if it
|
|
|
|
* fails, ask for a passphrase.
|
|
|
|
*/
|
|
|
|
if (!load_private_key(authfile, "", private_key, NULL)) {
|
|
|
|
char buf[300];
|
|
|
|
snprintf(buf, sizeof buf, "Enter passphrase for RSA key '%.100s': ",
|
|
|
|
comment);
|
|
|
|
if (!options.batch_mode)
|
|
|
|
passphrase = read_passphrase(buf, 0);
|
|
|
|
else {
|
|
|
|
debug("Will not query passphrase for %.100s in batch mode.",
|
|
|
|
comment);
|
|
|
|
passphrase = xstrdup("");
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Load the authentication file using the pasphrase. */
|
|
|
|
if (!load_private_key(authfile, passphrase, private_key, NULL)) {
|
|
|
|
memset(passphrase, 0, strlen(passphrase));
|
|
|
|
xfree(passphrase);
|
|
|
|
error("Bad passphrase.");
|
|
|
|
|
|
|
|
/* Send a dummy response packet to avoid protocol error. */
|
|
|
|
packet_start(SSH_CMSG_AUTH_RSA_RESPONSE);
|
|
|
|
for (i = 0; i < 16; i++)
|
|
|
|
packet_put_char(0);
|
|
|
|
packet_send();
|
|
|
|
packet_write_wait();
|
|
|
|
|
|
|
|
/* Expect the server to reject it... */
|
|
|
|
packet_read_expect(&plen, SSH_SMSG_FAILURE);
|
|
|
|
xfree(comment);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
/* Destroy the passphrase. */
|
|
|
|
memset(passphrase, 0, strlen(passphrase));
|
|
|
|
xfree(passphrase);
|
|
|
|
}
|
|
|
|
/* We no longer need the comment. */
|
|
|
|
xfree(comment);
|
|
|
|
|
|
|
|
/* Compute and send a response to the challenge. */
|
|
|
|
respond_to_rsa_challenge(challenge, private_key);
|
|
|
|
|
|
|
|
/* Destroy the private key. */
|
|
|
|
RSA_free(private_key);
|
|
|
|
|
|
|
|
/* We no longer need the challenge. */
|
|
|
|
BN_clear_free(challenge);
|
|
|
|
|
|
|
|
/* Wait for response from the server. */
|
|
|
|
type = packet_read(&plen);
|
|
|
|
if (type == SSH_SMSG_SUCCESS) {
|
|
|
|
debug("RSA authentication accepted by server.");
|
|
|
|
return 1;
|
|
|
|
}
|
|
|
|
if (type != SSH_SMSG_FAILURE)
|
|
|
|
packet_disconnect("Protocol error waiting RSA auth response: %d", type);
|
|
|
|
debug("RSA authentication refused.");
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Tries to authenticate the user using combined rhosts or /etc/hosts.equiv
|
|
|
|
* authentication and RSA host authentication.
|
|
|
|
*/
|
|
|
|
int
|
|
|
|
try_rhosts_rsa_authentication(const char *local_user, RSA * host_key)
|
|
|
|
{
|
|
|
|
int type;
|
|
|
|
BIGNUM *challenge;
|
|
|
|
int plen, clen;
|
|
|
|
|
|
|
|
debug("Trying rhosts or /etc/hosts.equiv with RSA host authentication.");
|
|
|
|
|
|
|
|
/* Tell the server that we are willing to authenticate using this key. */
|
|
|
|
packet_start(SSH_CMSG_AUTH_RHOSTS_RSA);
|
|
|
|
packet_put_string(local_user, strlen(local_user));
|
|
|
|
packet_put_int(BN_num_bits(host_key->n));
|
|
|
|
packet_put_bignum(host_key->e);
|
|
|
|
packet_put_bignum(host_key->n);
|
|
|
|
packet_send();
|
|
|
|
packet_write_wait();
|
|
|
|
|
|
|
|
/* Wait for server's response. */
|
|
|
|
type = packet_read(&plen);
|
|
|
|
|
|
|
|
/* The server responds with failure if it doesn't admit our
|
|
|
|
.rhosts authentication or doesn't know our host key. */
|
|
|
|
if (type == SSH_SMSG_FAILURE) {
|
|
|
|
debug("Server refused our rhosts authentication or host key.");
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
/* Otherwise, the server should respond with a challenge. */
|
|
|
|
if (type != SSH_SMSG_AUTH_RSA_CHALLENGE)
|
|
|
|
packet_disconnect("Protocol error during RSA authentication: %d", type);
|
|
|
|
|
|
|
|
/* Get the challenge from the packet. */
|
|
|
|
challenge = BN_new();
|
|
|
|
packet_get_bignum(challenge, &clen);
|
|
|
|
|
|
|
|
packet_integrity_check(plen, clen, type);
|
|
|
|
|
|
|
|
debug("Received RSA challenge for host key from server.");
|
|
|
|
|
|
|
|
/* Compute a response to the challenge. */
|
|
|
|
respond_to_rsa_challenge(challenge, host_key);
|
|
|
|
|
|
|
|
/* We no longer need the challenge. */
|
|
|
|
BN_clear_free(challenge);
|
|
|
|
|
|
|
|
/* Wait for response from the server. */
|
|
|
|
type = packet_read(&plen);
|
|
|
|
if (type == SSH_SMSG_SUCCESS) {
|
|
|
|
debug("Rhosts or /etc/hosts.equiv with RSA host authentication accepted by server.");
|
|
|
|
return 1;
|
|
|
|
}
|
|
|
|
if (type != SSH_SMSG_FAILURE)
|
|
|
|
packet_disconnect("Protocol error waiting RSA auth response: %d", type);
|
|
|
|
debug("Rhosts or /etc/hosts.equiv with RSA host authentication refused.");
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
#ifdef KRB4
|
|
|
|
int
|
2000-02-28 19:03:50 +00:00
|
|
|
try_krb4_authentication()
|
2000-02-24 14:29:47 +00:00
|
|
|
{
|
|
|
|
KTEXT_ST auth; /* Kerberos data */
|
|
|
|
char *reply;
|
|
|
|
char inst[INST_SZ];
|
|
|
|
char *realm;
|
|
|
|
CREDENTIALS cred;
|
|
|
|
int r, type, plen;
|
|
|
|
Key_schedule schedule;
|
|
|
|
u_long checksum, cksum;
|
|
|
|
MSG_DAT msg_data;
|
|
|
|
struct sockaddr_in local, foreign;
|
|
|
|
struct stat st;
|
|
|
|
|
|
|
|
/* Don't do anything if we don't have any tickets. */
|
|
|
|
if (stat(tkt_string(), &st) < 0)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
strncpy(inst, (char *) krb_get_phost(get_canonical_hostname()), INST_SZ);
|
|
|
|
|
|
|
|
realm = (char *) krb_realmofhost(get_canonical_hostname());
|
|
|
|
if (!realm) {
|
|
|
|
debug("Kerberos V4: no realm for %s", get_canonical_hostname());
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
/* This can really be anything. */
|
|
|
|
checksum = (u_long) getpid();
|
|
|
|
|
|
|
|
r = krb_mk_req(&auth, KRB4_SERVICE_NAME, inst, realm, checksum);
|
|
|
|
if (r != KSUCCESS) {
|
|
|
|
debug("Kerberos V4 krb_mk_req failed: %s", krb_err_txt[r]);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
/* Get session key to decrypt the server's reply with. */
|
|
|
|
r = krb_get_cred(KRB4_SERVICE_NAME, inst, realm, &cred);
|
|
|
|
if (r != KSUCCESS) {
|
|
|
|
debug("get_cred failed: %s", krb_err_txt[r]);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
des_key_sched((des_cblock *) cred.session, schedule);
|
|
|
|
|
|
|
|
/* Send authentication info to server. */
|
2000-02-28 19:03:50 +00:00
|
|
|
packet_start(SSH_CMSG_AUTH_KRB4);
|
2000-02-24 14:29:47 +00:00
|
|
|
packet_put_string((char *) auth.dat, auth.length);
|
|
|
|
packet_send();
|
|
|
|
packet_write_wait();
|
|
|
|
|
|
|
|
/* Zero the buffer. */
|
|
|
|
(void) memset(auth.dat, 0, MAX_KTXT_LEN);
|
|
|
|
|
|
|
|
r = sizeof(local);
|
|
|
|
memset(&local, 0, sizeof(local));
|
|
|
|
if (getsockname(packet_get_connection_in(),
|
|
|
|
(struct sockaddr *) & local, &r) < 0)
|
|
|
|
debug("getsockname failed: %s", strerror(errno));
|
|
|
|
|
|
|
|
r = sizeof(foreign);
|
|
|
|
memset(&foreign, 0, sizeof(foreign));
|
|
|
|
if (getpeername(packet_get_connection_in(),
|
|
|
|
(struct sockaddr *) & foreign, &r) < 0) {
|
|
|
|
debug("getpeername failed: %s", strerror(errno));
|
|
|
|
fatal_cleanup();
|
|
|
|
}
|
|
|
|
/* Get server reply. */
|
|
|
|
type = packet_read(&plen);
|
|
|
|
switch (type) {
|
|
|
|
case SSH_SMSG_FAILURE:
|
2000-02-28 19:03:50 +00:00
|
|
|
/* Should really be SSH_SMSG_AUTH_KRB4_FAILURE */
|
2000-02-24 14:29:47 +00:00
|
|
|
debug("Kerberos V4 authentication failed.");
|
|
|
|
return 0;
|
|
|
|
break;
|
|
|
|
|
2000-02-28 19:03:50 +00:00
|
|
|
case SSH_SMSG_AUTH_KRB4_RESPONSE:
|
|
|
|
/* SSH_SMSG_AUTH_KRB4_SUCCESS */
|
2000-02-24 14:29:47 +00:00
|
|
|
debug("Kerberos V4 authentication accepted.");
|
|
|
|
|
|
|
|
/* Get server's response. */
|
|
|
|
reply = packet_get_string((unsigned int *) &auth.length);
|
|
|
|
memcpy(auth.dat, reply, auth.length);
|
|
|
|
xfree(reply);
|
|
|
|
|
|
|
|
packet_integrity_check(plen, 4 + auth.length, type);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* If his response isn't properly encrypted with the session
|
|
|
|
* key, and the decrypted checksum fails to match, he's
|
|
|
|
* bogus. Bail out.
|
|
|
|
*/
|
|
|
|
r = krb_rd_priv(auth.dat, auth.length, schedule, &cred.session,
|
|
|
|
&foreign, &local, &msg_data);
|
|
|
|
if (r != KSUCCESS) {
|
|
|
|
debug("Kerberos V4 krb_rd_priv failed: %s", krb_err_txt[r]);
|
|
|
|
packet_disconnect("Kerberos V4 challenge failed!");
|
|
|
|
}
|
|
|
|
/* Fetch the (incremented) checksum that we supplied in the request. */
|
|
|
|
(void) memcpy((char *) &cksum, (char *) msg_data.app_data, sizeof(cksum));
|
|
|
|
cksum = ntohl(cksum);
|
|
|
|
|
|
|
|
/* If it matches, we're golden. */
|
|
|
|
if (cksum == checksum + 1) {
|
|
|
|
debug("Kerberos V4 challenge successful.");
|
|
|
|
return 1;
|
|
|
|
} else
|
|
|
|
packet_disconnect("Kerberos V4 challenge failed!");
|
|
|
|
break;
|
|
|
|
|
|
|
|
default:
|
|
|
|
packet_disconnect("Protocol error on Kerberos V4 response: %d", type);
|
|
|
|
}
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
#endif /* KRB4 */
|
|
|
|
|
|
|
|
#ifdef AFS
|
|
|
|
int
|
2000-02-28 19:03:50 +00:00
|
|
|
send_krb4_tgt()
|
2000-02-24 14:29:47 +00:00
|
|
|
{
|
|
|
|
CREDENTIALS *creds;
|
|
|
|
char pname[ANAME_SZ], pinst[INST_SZ], prealm[REALM_SZ];
|
|
|
|
int r, type, plen;
|
|
|
|
unsigned char buffer[8192];
|
|
|
|
struct stat st;
|
|
|
|
|
|
|
|
/* Don't do anything if we don't have any tickets. */
|
|
|
|
if (stat(tkt_string(), &st) < 0)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
creds = xmalloc(sizeof(*creds));
|
|
|
|
|
|
|
|
if ((r = krb_get_tf_fullname(TKT_FILE, pname, pinst, prealm)) != KSUCCESS) {
|
|
|
|
debug("Kerberos V4 tf_fullname failed: %s", krb_err_txt[r]);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
if ((r = krb_get_cred("krbtgt", prealm, prealm, creds)) != GC_OK) {
|
|
|
|
debug("Kerberos V4 get_cred failed: %s", krb_err_txt[r]);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
if (time(0) > krb_life_to_time(creds->issue_date, creds->lifetime)) {
|
|
|
|
debug("Kerberos V4 ticket expired: %s", TKT_FILE);
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
creds_to_radix(creds, buffer);
|
|
|
|
xfree(creds);
|
|
|
|
|
2000-02-28 19:03:50 +00:00
|
|
|
packet_start(SSH_CMSG_HAVE_KRB4_TGT);
|
2000-02-24 14:29:47 +00:00
|
|
|
packet_put_string((char *) buffer, strlen(buffer));
|
|
|
|
packet_send();
|
|
|
|
packet_write_wait();
|
|
|
|
|
|
|
|
type = packet_read(&plen);
|
|
|
|
|
|
|
|
if (type == SSH_SMSG_FAILURE)
|
|
|
|
debug("Kerberos TGT for realm %s rejected.", prealm);
|
|
|
|
else if (type != SSH_SMSG_SUCCESS)
|
|
|
|
packet_disconnect("Protocol error on Kerberos TGT response: %d", type);
|
|
|
|
|
|
|
|
return 1;
|
|
|
|
}
|
|
|
|
|
|
|
|
void
|
|
|
|
send_afs_tokens(void)
|
|
|
|
{
|
|
|
|
CREDENTIALS creds;
|
|
|
|
struct ViceIoctl parms;
|
|
|
|
struct ClearToken ct;
|
|
|
|
int i, type, len, plen;
|
|
|
|
char buf[2048], *p, *server_cell;
|
|
|
|
unsigned char buffer[8192];
|
|
|
|
|
|
|
|
/* Move over ktc_GetToken, here's something leaner. */
|
|
|
|
for (i = 0; i < 100; i++) { /* just in case */
|
|
|
|
parms.in = (char *) &i;
|
|
|
|
parms.in_size = sizeof(i);
|
|
|
|
parms.out = buf;
|
|
|
|
parms.out_size = sizeof(buf);
|
|
|
|
if (k_pioctl(0, VIOCGETTOK, &parms, 0) != 0)
|
|
|
|
break;
|
|
|
|
p = buf;
|
|
|
|
|
|
|
|
/* Get secret token. */
|
|
|
|
memcpy(&creds.ticket_st.length, p, sizeof(unsigned int));
|
|
|
|
if (creds.ticket_st.length > MAX_KTXT_LEN)
|
|
|
|
break;
|
|
|
|
p += sizeof(unsigned int);
|
|
|
|
memcpy(creds.ticket_st.dat, p, creds.ticket_st.length);
|
|
|
|
p += creds.ticket_st.length;
|
|
|
|
|
|
|
|
/* Get clear token. */
|
|
|
|
memcpy(&len, p, sizeof(len));
|
|
|
|
if (len != sizeof(struct ClearToken))
|
|
|
|
break;
|
|
|
|
p += sizeof(len);
|
|
|
|
memcpy(&ct, p, len);
|
|
|
|
p += len;
|
|
|
|
p += sizeof(len); /* primary flag */
|
|
|
|
server_cell = p;
|
|
|
|
|
|
|
|
/* Flesh out our credentials. */
|
|
|
|
strlcpy(creds.service, "afs", sizeof creds.service);
|
|
|
|
creds.instance[0] = '\0';
|
|
|
|
strlcpy(creds.realm, server_cell, REALM_SZ);
|
|
|
|
memcpy(creds.session, ct.HandShakeKey, DES_KEY_SZ);
|
|
|
|
creds.issue_date = ct.BeginTimestamp;
|
|
|
|
creds.lifetime = krb_time_to_life(creds.issue_date, ct.EndTimestamp);
|
|
|
|
creds.kvno = ct.AuthHandle;
|
|
|
|
snprintf(creds.pname, sizeof(creds.pname), "AFS ID %d", ct.ViceId);
|
|
|
|
creds.pinst[0] = '\0';
|
|
|
|
|
|
|
|
/* Encode token, ship it off. */
|
|
|
|
if (!creds_to_radix(&creds, buffer))
|
|
|
|
break;
|
|
|
|
packet_start(SSH_CMSG_HAVE_AFS_TOKEN);
|
|
|
|
packet_put_string((char *) buffer, strlen(buffer));
|
|
|
|
packet_send();
|
|
|
|
packet_write_wait();
|
|
|
|
|
|
|
|
/* Roger, Roger. Clearance, Clarence. What's your vector,
|
|
|
|
Victor? */
|
|
|
|
type = packet_read(&plen);
|
|
|
|
|
|
|
|
if (type == SSH_SMSG_FAILURE)
|
|
|
|
debug("AFS token for cell %s rejected.", server_cell);
|
|
|
|
else if (type != SSH_SMSG_SUCCESS)
|
|
|
|
packet_disconnect("Protocol error on AFS token response: %d", type);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
#endif /* AFS */
|
|
|
|
|
2000-02-28 19:03:50 +00:00
|
|
|
#ifdef KRB5
|
|
|
|
int
|
|
|
|
try_krb5_authentication(krb5_context *context, krb5_auth_context *auth_context)
|
|
|
|
{
|
|
|
|
krb5_error_code problem;
|
|
|
|
const char *tkfile;
|
|
|
|
struct stat buf;
|
|
|
|
krb5_ccache ccache = NULL;
|
|
|
|
krb5_creds req_creds;
|
|
|
|
krb5_creds *new_creds = NULL;
|
|
|
|
const char *remotehost;
|
|
|
|
krb5_data ap;
|
|
|
|
int type, payload_len;
|
|
|
|
krb5_ap_rep_enc_part *reply = NULL;
|
|
|
|
int ret;
|
|
|
|
|
|
|
|
memset(&ap, 0, sizeof(ap));
|
|
|
|
|
|
|
|
problem = krb5_init_context(context);
|
|
|
|
if (problem) {
|
|
|
|
ret = 0;
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
tkfile = krb5_cc_default_name(*context);
|
|
|
|
if (strncmp(tkfile, "FILE:", 5) == 0)
|
|
|
|
tkfile += 5;
|
|
|
|
|
|
|
|
if (stat(tkfile, &buf) == 0 && getuid() != buf.st_uid) {
|
|
|
|
debug("Kerberos V5: could not get default ccache (permission denied).");
|
|
|
|
ret = 0;
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
problem = krb5_cc_default(*context, &ccache);
|
|
|
|
if (problem) {
|
|
|
|
ret = 0;
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
memset(&req_creds, 0, sizeof(req_creds));
|
|
|
|
|
|
|
|
remotehost = get_canonical_hostname();
|
|
|
|
|
|
|
|
problem = krb5_sname_to_principal(*context, remotehost,
|
|
|
|
"host", KRB5_NT_SRV_HST,
|
|
|
|
&req_creds.server);
|
|
|
|
if (problem) {
|
|
|
|
ret = 0;
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
}
|
|
|
|
|
|
|
|
problem = krb5_cc_get_principal(*context, ccache, &req_creds.client);
|
|
|
|
if (problem) {
|
|
|
|
ret = 0;
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* creds.session.keytype=ETYPE_DES_CBC_CRC; */
|
|
|
|
|
|
|
|
problem = krb5_get_credentials(*context, 0, ccache, &req_creds, &new_creds);
|
|
|
|
if (problem) {
|
|
|
|
ret = 0;
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
problem = krb5_auth_con_init(*context, auth_context);
|
|
|
|
if (problem) {
|
|
|
|
ret = 0;
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* krb5_auth_con_setflags(ssh_context, auth_context,
|
|
|
|
KRB5_AUTH_CONTEXT_RET_TIME);
|
|
|
|
*/
|
|
|
|
problem = krb5_mk_req_extended(*context, auth_context,
|
|
|
|
AP_OPTS_MUTUAL_REQUIRED /*| AP_OPTS_USE_SUBKEY*/ ,
|
|
|
|
NULL, new_creds, &ap);
|
|
|
|
if (problem) {
|
|
|
|
ret = 0;
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
packet_start(SSH_CMSG_AUTH_KRB5);
|
|
|
|
packet_put_string((char *) ap.data, ap.length);
|
|
|
|
packet_send();
|
|
|
|
packet_write_wait();
|
|
|
|
|
|
|
|
xfree(ap.data);
|
|
|
|
ap.length = 0;
|
|
|
|
|
|
|
|
type = packet_read(&payload_len);
|
|
|
|
switch (type) {
|
|
|
|
case SSH_SMSG_FAILURE:
|
|
|
|
/* Should really be SSH_SMSG_AUTH_KRB5_FAILURE */
|
|
|
|
debug("Kerberos V5 authentication failed.");
|
|
|
|
ret = 0;
|
|
|
|
break;
|
|
|
|
|
|
|
|
case SSH_SMSG_AUTH_KRB5_RESPONSE:
|
|
|
|
/* SSH_SMSG_AUTH_KRB5_SUCCESS */
|
|
|
|
debug("Kerberos V5 authentication accepted.");
|
|
|
|
|
|
|
|
/* Get server's response. */
|
|
|
|
ap.data = packet_get_string((unsigned int *) &ap.length);
|
|
|
|
|
|
|
|
packet_integrity_check(payload_len, 4 + ap.length, type);
|
|
|
|
/* XXX je to dobre? */
|
|
|
|
|
|
|
|
problem = krb5_rd_rep(*context, *auth_context, &ap, &reply);
|
|
|
|
if (problem) {
|
|
|
|
ret = 0;
|
|
|
|
}
|
|
|
|
ret = 1;
|
|
|
|
break;
|
|
|
|
|
|
|
|
default:
|
|
|
|
packet_disconnect("Protocol error on Kerberos V5 response: %d", type);
|
|
|
|
ret = 0;
|
|
|
|
break;
|
|
|
|
|
|
|
|
}
|
|
|
|
|
|
|
|
out:
|
|
|
|
if (req_creds.server != NULL)
|
|
|
|
krb5_free_principal(*context, req_creds.server);
|
|
|
|
if (req_creds.client != NULL)
|
|
|
|
krb5_free_principal(*context, req_creds.client);
|
|
|
|
if (new_creds != NULL)
|
|
|
|
krb5_free_creds(*context, new_creds);
|
|
|
|
if (ccache != NULL)
|
|
|
|
krb5_cc_close(*context, ccache);
|
|
|
|
if (reply != NULL)
|
|
|
|
krb5_free_ap_rep_enc_part(*context, reply);
|
|
|
|
if (ap.length > 0)
|
|
|
|
krb5_data_free(&ap);
|
|
|
|
|
|
|
|
return ret;
|
|
|
|
|
|
|
|
}
|
|
|
|
|
|
|
|
void
|
|
|
|
send_krb5_tgt(krb5_context context, krb5_auth_context auth_context)
|
|
|
|
{
|
|
|
|
int fd;
|
|
|
|
int type, payload_len;
|
|
|
|
krb5_error_code problem;
|
|
|
|
krb5_data outbuf;
|
|
|
|
krb5_ccache ccache = NULL;
|
|
|
|
krb5_creds creds;
|
|
|
|
krb5_kdc_flags flags;
|
|
|
|
const char* remotehost = get_canonical_hostname();
|
|
|
|
|
|
|
|
memset(&creds, 0, sizeof(creds));
|
|
|
|
memset(&outbuf, 0, sizeof(outbuf));
|
|
|
|
|
|
|
|
fd = packet_get_connection_in();
|
|
|
|
problem = krb5_auth_con_setaddrs_from_fd(context, auth_context, &fd);
|
|
|
|
if (problem) {
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
#if 0
|
|
|
|
tkfile = krb5_cc_default_name(context);
|
|
|
|
if (strncmp(tkfile, "FILE:", 5) == 0)
|
|
|
|
tkfile += 5;
|
|
|
|
|
|
|
|
if (stat(tkfile, &buf) == 0 && getuid() != buf.st_uid) {
|
|
|
|
debug("Kerberos V5: could not get default ccache (permission denied).");
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
#endif
|
|
|
|
|
|
|
|
problem = krb5_cc_default(context, &ccache);
|
|
|
|
if (problem) {
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
problem = krb5_cc_get_principal(context, ccache, &creds.client);
|
|
|
|
if (problem) {
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
problem = krb5_build_principal(context, &creds.server,
|
|
|
|
strlen(creds.client->realm),
|
|
|
|
creds.client->realm,
|
|
|
|
"krbtgt",
|
|
|
|
creds.client->realm,
|
|
|
|
NULL);
|
|
|
|
if (problem) {
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
creds.times.endtime = 0;
|
|
|
|
|
|
|
|
flags.i = 0;
|
|
|
|
flags.b.forwarded = 1;
|
|
|
|
flags.b.forwardable = krb5_config_get_bool(context, NULL,
|
|
|
|
"libdefaults", "forwardable", NULL);
|
|
|
|
|
|
|
|
problem = krb5_get_forwarded_creds (context,
|
|
|
|
auth_context,
|
|
|
|
ccache,
|
|
|
|
flags.i,
|
|
|
|
remotehost,
|
|
|
|
&creds,
|
|
|
|
&outbuf);
|
|
|
|
if (problem) {
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
packet_start(SSH_CMSG_HAVE_KRB5_TGT);
|
|
|
|
packet_put_string((char *)outbuf.data, outbuf.length);
|
|
|
|
packet_send();
|
|
|
|
packet_write_wait();
|
|
|
|
|
|
|
|
type = packet_read(&payload_len);
|
|
|
|
switch (type) {
|
|
|
|
case SSH_SMSG_SUCCESS:
|
|
|
|
break;
|
|
|
|
case SSH_SMSG_FAILURE:
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
|
|
|
|
out:
|
|
|
|
if (creds.client)
|
|
|
|
krb5_free_principal(context, creds.client);
|
|
|
|
if (creds.server)
|
|
|
|
krb5_free_principal(context, creds.server);
|
|
|
|
if (ccache)
|
|
|
|
krb5_cc_close(context, ccache);
|
|
|
|
if (outbuf.data)
|
|
|
|
xfree(outbuf.data);
|
|
|
|
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
#endif /* KRB5 */
|
|
|
|
|
2000-02-24 14:29:47 +00:00
|
|
|
/*
|
|
|
|
* Tries to authenticate with any string-based challenge/response system.
|
|
|
|
* Note that the client code is not tied to s/key or TIS.
|
|
|
|
*/
|
|
|
|
int
|
|
|
|
try_skey_authentication()
|
|
|
|
{
|
|
|
|
int type, i, payload_len;
|
|
|
|
char *challenge, *response;
|
|
|
|
|
|
|
|
debug("Doing skey authentication.");
|
|
|
|
|
|
|
|
/* request a challenge */
|
|
|
|
packet_start(SSH_CMSG_AUTH_TIS);
|
|
|
|
packet_send();
|
|
|
|
packet_write_wait();
|
|
|
|
|
|
|
|
type = packet_read(&payload_len);
|
|
|
|
if (type != SSH_SMSG_FAILURE &&
|
|
|
|
type != SSH_SMSG_AUTH_TIS_CHALLENGE) {
|
|
|
|
packet_disconnect("Protocol error: got %d in response "
|
|
|
|
"to skey-auth", type);
|
|
|
|
}
|
|
|
|
if (type != SSH_SMSG_AUTH_TIS_CHALLENGE) {
|
|
|
|
debug("No challenge for skey authentication.");
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
challenge = packet_get_string(&payload_len);
|
|
|
|
if (options.cipher == SSH_CIPHER_NONE)
|
|
|
|
log("WARNING: Encryption is disabled! "
|
|
|
|
"Reponse will be transmitted in clear text.");
|
|
|
|
fprintf(stderr, "%s\n", challenge);
|
|
|
|
xfree(challenge);
|
|
|
|
fflush(stderr);
|
|
|
|
for (i = 0; i < options.number_of_password_prompts; i++) {
|
|
|
|
if (i != 0)
|
|
|
|
error("Permission denied, please try again.");
|
|
|
|
response = read_passphrase("Response: ", 0);
|
|
|
|
packet_start(SSH_CMSG_AUTH_TIS_RESPONSE);
|
|
|
|
packet_put_string(response, strlen(response));
|
|
|
|
memset(response, 0, strlen(response));
|
|
|
|
xfree(response);
|
|
|
|
packet_send();
|
|
|
|
packet_write_wait();
|
|
|
|
type = packet_read(&payload_len);
|
|
|
|
if (type == SSH_SMSG_SUCCESS)
|
|
|
|
return 1;
|
|
|
|
if (type != SSH_SMSG_FAILURE)
|
|
|
|
packet_disconnect("Protocol error: got %d in response "
|
|
|
|
"to skey-auth-reponse", type);
|
|
|
|
}
|
|
|
|
/* failure */
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Tries to authenticate with plain passwd authentication.
|
|
|
|
*/
|
|
|
|
int
|
|
|
|
try_password_authentication(char *prompt)
|
|
|
|
{
|
|
|
|
int type, i, payload_len;
|
|
|
|
char *password;
|
|
|
|
|
|
|
|
debug("Doing password authentication.");
|
|
|
|
if (options.cipher == SSH_CIPHER_NONE)
|
|
|
|
log("WARNING: Encryption is disabled! Password will be transmitted in clear text.");
|
|
|
|
for (i = 0; i < options.number_of_password_prompts; i++) {
|
|
|
|
if (i != 0)
|
|
|
|
error("Permission denied, please try again.");
|
|
|
|
password = read_passphrase(prompt, 0);
|
|
|
|
packet_start(SSH_CMSG_AUTH_PASSWORD);
|
|
|
|
packet_put_string(password, strlen(password));
|
|
|
|
memset(password, 0, strlen(password));
|
|
|
|
xfree(password);
|
|
|
|
packet_send();
|
|
|
|
packet_write_wait();
|
|
|
|
|
|
|
|
type = packet_read(&payload_len);
|
|
|
|
if (type == SSH_SMSG_SUCCESS)
|
|
|
|
return 1;
|
|
|
|
if (type != SSH_SMSG_FAILURE)
|
|
|
|
packet_disconnect("Protocol error: got %d in response to passwd auth", type);
|
|
|
|
}
|
|
|
|
/* failure */
|
|
|
|
return 0;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Waits for the server identification string, and sends our own
|
|
|
|
* identification string.
|
|
|
|
*/
|
|
|
|
void
|
|
|
|
ssh_exchange_identification()
|
|
|
|
{
|
|
|
|
char buf[256], remote_version[256]; /* must be same size! */
|
|
|
|
int remote_major, remote_minor, i;
|
|
|
|
int connection_in = packet_get_connection_in();
|
|
|
|
int connection_out = packet_get_connection_out();
|
|
|
|
|
|
|
|
/* Read other side\'s version identification. */
|
|
|
|
for (i = 0; i < sizeof(buf) - 1; i++) {
|
|
|
|
int len = read(connection_in, &buf[i], 1);
|
|
|
|
if (len < 0)
|
|
|
|
fatal("ssh_exchange_identification: read: %.100s", strerror(errno));
|
|
|
|
if (len != 1)
|
|
|
|
fatal("ssh_exchange_identification: Connection closed by remote host");
|
|
|
|
if (buf[i] == '\r') {
|
|
|
|
buf[i] = '\n';
|
|
|
|
buf[i + 1] = 0;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
if (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)
|
|
|
|
fatal("Bad remote protocol version identification: '%.100s'", buf);
|
|
|
|
debug("Remote protocol version %d.%d, remote software version %.100s",
|
|
|
|
remote_major, remote_minor, remote_version);
|
|
|
|
|
|
|
|
/* Check if the remote protocol version is too old. */
|
|
|
|
if (remote_major == 1 && remote_minor < 3)
|
|
|
|
fatal("Remote machine has too old SSH software version.");
|
|
|
|
|
|
|
|
/* We speak 1.3, too. */
|
|
|
|
if (remote_major == 1 && remote_minor == 3) {
|
|
|
|
enable_compat13();
|
|
|
|
if (options.forward_agent) {
|
|
|
|
log("Agent forwarding disabled for protocol 1.3");
|
|
|
|
options.forward_agent = 0;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
#if 0
|
|
|
|
/*
|
|
|
|
* Removed for now, to permit compatibility with latter versions. The
|
|
|
|
* server will reject our version and disconnect if it doesn't
|
|
|
|
* support it.
|
|
|
|
*/
|
|
|
|
if (remote_major != PROTOCOL_MAJOR)
|
|
|
|
fatal("Protocol major versions differ: %d vs. %d",
|
|
|
|
PROTOCOL_MAJOR, remote_major);
|
|
|
|
#endif
|
|
|
|
|
|
|
|
/* Send our own protocol version identification. */
|
|
|
|
snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
|
|
|
|
PROTOCOL_MAJOR, PROTOCOL_MINOR, SSH_VERSION);
|
|
|
|
if (atomicio(write, connection_out, buf, strlen(buf)) != strlen(buf))
|
|
|
|
fatal("write: %.100s", strerror(errno));
|
|
|
|
}
|
|
|
|
|
|
|
|
int ssh_cipher_default = SSH_CIPHER_3DES;
|
|
|
|
|
|
|
|
int
|
|
|
|
read_yes_or_no(const char *prompt, int defval)
|
|
|
|
{
|
|
|
|
char buf[1024];
|
|
|
|
FILE *f;
|
|
|
|
int retval = -1;
|
|
|
|
|
|
|
|
if (isatty(0))
|
|
|
|
f = stdin;
|
|
|
|
else
|
|
|
|
f = fopen("/dev/tty", "rw");
|
|
|
|
|
|
|
|
if (f == NULL)
|
|
|
|
return 0;
|
|
|
|
|
|
|
|
fflush(stdout);
|
|
|
|
|
|
|
|
while (1) {
|
|
|
|
fprintf(stderr, "%s", prompt);
|
|
|
|
if (fgets(buf, sizeof(buf), f) == NULL) {
|
|
|
|
/* Print a newline (the prompt probably didn\'t have one). */
|
|
|
|
fprintf(stderr, "\n");
|
|
|
|
strlcpy(buf, "no", sizeof buf);
|
|
|
|
}
|
|
|
|
/* Remove newline from response. */
|
|
|
|
if (strchr(buf, '\n'))
|
|
|
|
*strchr(buf, '\n') = 0;
|
|
|
|
|
|
|
|
if (buf[0] == 0)
|
|
|
|
retval = defval;
|
|
|
|
if (strcmp(buf, "yes") == 0)
|
|
|
|
retval = 1;
|
|
|
|
if (strcmp(buf, "no") == 0)
|
|
|
|
retval = 0;
|
|
|
|
|
|
|
|
if (retval != -1) {
|
|
|
|
if (f != stdin)
|
|
|
|
fclose(f);
|
|
|
|
return retval;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* check whether the supplied host key is valid, return only if ok.
|
|
|
|
*/
|
|
|
|
|
|
|
|
void
|
|
|
|
check_host_key(char *host, struct sockaddr *hostaddr, RSA *host_key)
|
|
|
|
{
|
|
|
|
RSA *file_key;
|
|
|
|
char *ip = NULL;
|
|
|
|
char hostline[1000], *hostp;
|
|
|
|
HostStatus host_status;
|
|
|
|
HostStatus ip_status;
|
|
|
|
int local = 0, host_ip_differ = 0;
|
|
|
|
char ntop[NI_MAXHOST];
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Force accepting of the host key for loopback/localhost. The
|
|
|
|
* problem is that if the home directory is NFS-mounted to multiple
|
|
|
|
* machines, localhost will refer to a different machine in each of
|
|
|
|
* them, and the user will get bogus HOST_CHANGED warnings. This
|
|
|
|
* essentially disables host authentication for localhost; however,
|
|
|
|
* this is probably not a real problem.
|
|
|
|
*/
|
|
|
|
switch (hostaddr->sa_family) {
|
|
|
|
case AF_INET:
|
|
|
|
local = (ntohl(((struct sockaddr_in *)hostaddr)->sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
|
|
|
|
break;
|
|
|
|
case AF_INET6:
|
|
|
|
local = IN6_IS_ADDR_LOOPBACK(&(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
local = 0;
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
if (local) {
|
|
|
|
debug("Forcing accepting of host key for loopback/localhost.");
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Turn off check_host_ip for proxy connects, since
|
|
|
|
* we don't have the remote ip-address
|
|
|
|
*/
|
|
|
|
if (options.proxy_command != NULL && options.check_host_ip)
|
|
|
|
options.check_host_ip = 0;
|
|
|
|
|
|
|
|
if (options.check_host_ip) {
|
|
|
|
if (getnameinfo(hostaddr, hostaddr->sa_len, ntop, sizeof(ntop),
|
|
|
|
NULL, 0, NI_NUMERICHOST) != 0)
|
|
|
|
fatal("check_host_key: getnameinfo failed");
|
|
|
|
ip = xstrdup(ntop);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Store the host key from the known host file in here so that we can
|
|
|
|
* compare it with the key for the IP address.
|
|
|
|
*/
|
|
|
|
file_key = RSA_new();
|
|
|
|
file_key->n = BN_new();
|
|
|
|
file_key->e = BN_new();
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Check if the host key is present in the user\'s list of known
|
|
|
|
* hosts or in the systemwide list.
|
|
|
|
*/
|
|
|
|
host_status = check_host_in_hostfile(options.user_hostfile, host,
|
|
|
|
host_key->e, host_key->n,
|
|
|
|
file_key->e, file_key->n);
|
|
|
|
if (host_status == HOST_NEW)
|
|
|
|
host_status = check_host_in_hostfile(options.system_hostfile, host,
|
|
|
|
host_key->e, host_key->n,
|
|
|
|
file_key->e, file_key->n);
|
|
|
|
/*
|
|
|
|
* Also perform check for the ip address, skip the check if we are
|
|
|
|
* localhost or the hostname was an ip address to begin with
|
|
|
|
*/
|
|
|
|
if (options.check_host_ip && !local && strcmp(host, ip)) {
|
|
|
|
RSA *ip_key = RSA_new();
|
|
|
|
ip_key->n = BN_new();
|
|
|
|
ip_key->e = BN_new();
|
|
|
|
ip_status = check_host_in_hostfile(options.user_hostfile, ip,
|
|
|
|
host_key->e, host_key->n,
|
|
|
|
ip_key->e, ip_key->n);
|
|
|
|
|
|
|
|
if (ip_status == HOST_NEW)
|
|
|
|
ip_status = check_host_in_hostfile(options.system_hostfile, ip,
|
|
|
|
host_key->e, host_key->n,
|
|
|
|
ip_key->e, ip_key->n);
|
|
|
|
if (host_status == HOST_CHANGED &&
|
|
|
|
(ip_status != HOST_CHANGED ||
|
|
|
|
(BN_cmp(ip_key->e, file_key->e) || BN_cmp(ip_key->n, file_key->n))))
|
|
|
|
host_ip_differ = 1;
|
|
|
|
|
|
|
|
RSA_free(ip_key);
|
|
|
|
} else
|
|
|
|
ip_status = host_status;
|
|
|
|
|
|
|
|
RSA_free(file_key);
|
|
|
|
|
|
|
|
switch (host_status) {
|
|
|
|
case HOST_OK:
|
|
|
|
/* The host is known and the key matches. */
|
|
|
|
debug("Host '%.200s' is known and matches the host key.", host);
|
|
|
|
if (options.check_host_ip) {
|
|
|
|
if (ip_status == HOST_NEW) {
|
|
|
|
if (!add_host_to_hostfile(options.user_hostfile, ip,
|
|
|
|
host_key->e, host_key->n))
|
|
|
|
log("Failed to add the host key for IP address '%.30s' to the list of known hosts (%.30s).",
|
|
|
|
ip, options.user_hostfile);
|
|
|
|
else
|
|
|
|
log("Warning: Permanently added host key for IP address '%.30s' to the list of known hosts.",
|
|
|
|
ip);
|
|
|
|
} else if (ip_status != HOST_OK)
|
|
|
|
log("Warning: the host key for '%.200s' differs from the key for the IP address '%.30s'",
|
|
|
|
host, ip);
|
|
|
|
}
|
|
|
|
break;
|
|
|
|
case HOST_NEW:
|
|
|
|
/* The host is new. */
|
|
|
|
if (options.strict_host_key_checking == 1) {
|
|
|
|
/* User has requested strict host key checking. We will not add the host key
|
|
|
|
automatically. The only alternative left is to abort. */
|
|
|
|
fatal("No host key is known for %.200s and you have requested strict checking.", host);
|
|
|
|
} else if (options.strict_host_key_checking == 2) {
|
|
|
|
/* The default */
|
|
|
|
char prompt[1024];
|
|
|
|
char *fp = fingerprint(host_key->e, host_key->n);
|
|
|
|
snprintf(prompt, sizeof(prompt),
|
|
|
|
"The authenticity of host '%.200s' can't be established.\n"
|
|
|
|
"Key fingerprint is %d %s.\n"
|
|
|
|
"Are you sure you want to continue connecting (yes/no)? ",
|
|
|
|
host, BN_num_bits(host_key->n), fp);
|
|
|
|
if (!read_yes_or_no(prompt, -1))
|
|
|
|
fatal("Aborted by user!\n");
|
|
|
|
}
|
|
|
|
if (options.check_host_ip && ip_status == HOST_NEW && strcmp(host, ip)) {
|
|
|
|
snprintf(hostline, sizeof(hostline), "%s,%s", host, ip);
|
|
|
|
hostp = hostline;
|
|
|
|
} else
|
|
|
|
hostp = host;
|
|
|
|
|
|
|
|
/* If not in strict mode, add the key automatically to the local known_hosts file. */
|
|
|
|
if (!add_host_to_hostfile(options.user_hostfile, hostp,
|
|
|
|
host_key->e, host_key->n))
|
|
|
|
log("Failed to add the host to the list of known hosts (%.500s).",
|
|
|
|
options.user_hostfile);
|
|
|
|
else
|
|
|
|
log("Warning: Permanently added '%.200s' to the list of known hosts.",
|
|
|
|
hostp);
|
|
|
|
break;
|
|
|
|
case HOST_CHANGED:
|
|
|
|
if (options.check_host_ip && host_ip_differ) {
|
|
|
|
char *msg;
|
|
|
|
if (ip_status == HOST_NEW)
|
|
|
|
msg = "is unknown";
|
|
|
|
else if (ip_status == HOST_OK)
|
|
|
|
msg = "is unchanged";
|
|
|
|
else
|
|
|
|
msg = "has a different value";
|
|
|
|
error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
|
|
|
|
error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
|
|
|
|
error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
|
|
|
|
error("The host key for %s has changed,", host);
|
|
|
|
error("and the key for the according IP address %s", ip);
|
|
|
|
error("%s. This could either mean that", msg);
|
|
|
|
error("DNS SPOOFING is happening or the IP address for the host");
|
|
|
|
error("and its host key have changed at the same time");
|
|
|
|
}
|
|
|
|
/* The host key has changed. */
|
|
|
|
error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
|
|
|
|
error("@ WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED! @");
|
|
|
|
error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
|
|
|
|
error("IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!");
|
|
|
|
error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!");
|
|
|
|
error("It is also possible that the host key has just been changed.");
|
|
|
|
error("Please contact your system administrator.");
|
|
|
|
error("Add correct host key in %.100s to get rid of this message.",
|
|
|
|
options.user_hostfile);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* If strict host key checking is in use, the user will have
|
|
|
|
* to edit the key manually and we can only abort.
|
|
|
|
*/
|
|
|
|
if (options.strict_host_key_checking)
|
|
|
|
fatal("Host key for %.200s has changed and you have requested strict checking.", host);
|
|
|
|
|
|
|
|
/*
|
|
|
|
* If strict host key checking has not been requested, allow
|
|
|
|
* the connection but without password authentication or
|
|
|
|
* agent forwarding.
|
|
|
|
*/
|
|
|
|
if (options.password_authentication) {
|
|
|
|
error("Password authentication is disabled to avoid trojan horses.");
|
|
|
|
options.password_authentication = 0;
|
|
|
|
}
|
|
|
|
if (options.forward_agent) {
|
|
|
|
error("Agent forwarding is disabled to avoid trojan horses.");
|
|
|
|
options.forward_agent = 0;
|
|
|
|
}
|
|
|
|
/*
|
|
|
|
* XXX Should permit the user to change to use the new id.
|
|
|
|
* This could be done by converting the host key to an
|
|
|
|
* identifying sentence, tell that the host identifies itself
|
|
|
|
* by that sentence, and ask the user if he/she whishes to
|
|
|
|
* accept the authentication.
|
|
|
|
*/
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
if (options.check_host_ip)
|
|
|
|
xfree(ip);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* SSH1 key exchange
|
|
|
|
*/
|
|
|
|
void
|
|
|
|
ssh_kex(char *host, struct sockaddr *hostaddr)
|
|
|
|
{
|
|
|
|
int i;
|
|
|
|
BIGNUM *key;
|
|
|
|
RSA *host_key;
|
|
|
|
RSA *public_key;
|
|
|
|
int bits, rbits;
|
|
|
|
unsigned char session_key[SSH_SESSION_KEY_LENGTH];
|
|
|
|
unsigned char cookie[8];
|
|
|
|
unsigned int supported_ciphers;
|
|
|
|
unsigned int server_flags, client_flags;
|
|
|
|
int payload_len, clen, sum_len = 0;
|
|
|
|
u_int32_t rand = 0;
|
|
|
|
|
|
|
|
debug("Waiting for server public key.");
|
|
|
|
|
|
|
|
/* Wait for a public key packet from the server. */
|
|
|
|
packet_read_expect(&payload_len, SSH_SMSG_PUBLIC_KEY);
|
|
|
|
|
|
|
|
/* Get cookie from the packet. */
|
|
|
|
for (i = 0; i < 8; i++)
|
|
|
|
cookie[i] = packet_get_char();
|
|
|
|
|
|
|
|
/* Get the public key. */
|
|
|
|
public_key = RSA_new();
|
|
|
|
bits = packet_get_int();/* bits */
|
|
|
|
public_key->e = BN_new();
|
|
|
|
packet_get_bignum(public_key->e, &clen);
|
|
|
|
sum_len += clen;
|
|
|
|
public_key->n = BN_new();
|
|
|
|
packet_get_bignum(public_key->n, &clen);
|
|
|
|
sum_len += clen;
|
|
|
|
|
|
|
|
rbits = BN_num_bits(public_key->n);
|
|
|
|
if (bits != rbits) {
|
|
|
|
log("Warning: Server lies about size of server public key: "
|
|
|
|
"actual size is %d bits vs. announced %d.", rbits, bits);
|
|
|
|
log("Warning: This may be due to an old implementation of ssh.");
|
|
|
|
}
|
|
|
|
/* Get the host key. */
|
|
|
|
host_key = RSA_new();
|
|
|
|
bits = packet_get_int();/* bits */
|
|
|
|
host_key->e = BN_new();
|
|
|
|
packet_get_bignum(host_key->e, &clen);
|
|
|
|
sum_len += clen;
|
|
|
|
host_key->n = BN_new();
|
|
|
|
packet_get_bignum(host_key->n, &clen);
|
|
|
|
sum_len += clen;
|
|
|
|
|
|
|
|
rbits = BN_num_bits(host_key->n);
|
|
|
|
if (bits != rbits) {
|
|
|
|
log("Warning: Server lies about size of server host key: "
|
|
|
|
"actual size is %d bits vs. announced %d.", rbits, bits);
|
|
|
|
log("Warning: This may be due to an old implementation of ssh.");
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Get protocol flags. */
|
|
|
|
server_flags = packet_get_int();
|
|
|
|
packet_set_protocol_flags(server_flags);
|
|
|
|
|
|
|
|
supported_ciphers = packet_get_int();
|
|
|
|
supported_authentications = packet_get_int();
|
|
|
|
|
|
|
|
debug("Received server public key (%d bits) and host key (%d bits).",
|
|
|
|
BN_num_bits(public_key->n), BN_num_bits(host_key->n));
|
|
|
|
|
|
|
|
packet_integrity_check(payload_len,
|
|
|
|
8 + 4 + sum_len + 0 + 4 + 0 + 0 + 4 + 4 + 4,
|
|
|
|
SSH_SMSG_PUBLIC_KEY);
|
|
|
|
|
|
|
|
check_host_key(host, hostaddr, host_key);
|
|
|
|
|
|
|
|
client_flags = SSH_PROTOFLAG_SCREEN_NUMBER | SSH_PROTOFLAG_HOST_IN_FWD_OPEN;
|
|
|
|
|
|
|
|
compute_session_id(session_id, cookie, host_key->n, public_key->n);
|
|
|
|
|
|
|
|
/* Generate a session key. */
|
|
|
|
arc4random_stir();
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Generate an encryption key for the session. The key is a 256 bit
|
|
|
|
* random number, interpreted as a 32-byte key, with the least
|
|
|
|
* significant 8 bits being the first byte of the key.
|
|
|
|
*/
|
|
|
|
for (i = 0; i < 32; i++) {
|
|
|
|
if (i % 4 == 0)
|
|
|
|
rand = arc4random();
|
|
|
|
session_key[i] = rand & 0xff;
|
|
|
|
rand >>= 8;
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* According to the protocol spec, the first byte of the session key
|
|
|
|
* is the highest byte of the integer. The session key is xored with
|
|
|
|
* the first 16 bytes of the session id.
|
|
|
|
*/
|
|
|
|
key = BN_new();
|
|
|
|
BN_set_word(key, 0);
|
|
|
|
for (i = 0; i < SSH_SESSION_KEY_LENGTH; i++) {
|
|
|
|
BN_lshift(key, key, 8);
|
|
|
|
if (i < 16)
|
|
|
|
BN_add_word(key, session_key[i] ^ session_id[i]);
|
|
|
|
else
|
|
|
|
BN_add_word(key, session_key[i]);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Encrypt the integer using the public key and host key of the
|
|
|
|
* server (key with smaller modulus first).
|
|
|
|
*/
|
|
|
|
if (BN_cmp(public_key->n, host_key->n) < 0) {
|
|
|
|
/* Public key has smaller modulus. */
|
|
|
|
if (BN_num_bits(host_key->n) <
|
|
|
|
BN_num_bits(public_key->n) + SSH_KEY_BITS_RESERVED) {
|
|
|
|
fatal("respond_to_rsa_challenge: host_key %d < public_key %d + "
|
|
|
|
"SSH_KEY_BITS_RESERVED %d",
|
|
|
|
BN_num_bits(host_key->n),
|
|
|
|
BN_num_bits(public_key->n),
|
|
|
|
SSH_KEY_BITS_RESERVED);
|
|
|
|
}
|
|
|
|
rsa_public_encrypt(key, key, public_key);
|
|
|
|
rsa_public_encrypt(key, key, host_key);
|
|
|
|
} else {
|
|
|
|
/* Host key has smaller modulus (or they are equal). */
|
|
|
|
if (BN_num_bits(public_key->n) <
|
|
|
|
BN_num_bits(host_key->n) + SSH_KEY_BITS_RESERVED) {
|
|
|
|
fatal("respond_to_rsa_challenge: public_key %d < host_key %d + "
|
|
|
|
"SSH_KEY_BITS_RESERVED %d",
|
|
|
|
BN_num_bits(public_key->n),
|
|
|
|
BN_num_bits(host_key->n),
|
|
|
|
SSH_KEY_BITS_RESERVED);
|
|
|
|
}
|
|
|
|
rsa_public_encrypt(key, key, host_key);
|
|
|
|
rsa_public_encrypt(key, key, public_key);
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Destroy the public keys since we no longer need them. */
|
|
|
|
RSA_free(public_key);
|
|
|
|
RSA_free(host_key);
|
|
|
|
|
|
|
|
if (options.cipher == SSH_CIPHER_NOT_SET) {
|
|
|
|
if (cipher_mask() & supported_ciphers & (1 << ssh_cipher_default))
|
|
|
|
options.cipher = ssh_cipher_default;
|
|
|
|
else {
|
|
|
|
debug("Cipher %s not supported, using %.100s instead.",
|
|
|
|
cipher_name(ssh_cipher_default),
|
|
|
|
cipher_name(SSH_FALLBACK_CIPHER));
|
|
|
|
options.cipher = SSH_FALLBACK_CIPHER;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
/* Check that the selected cipher is supported. */
|
|
|
|
if (!(supported_ciphers & (1 << options.cipher)))
|
|
|
|
fatal("Selected cipher type %.100s not supported by server.",
|
|
|
|
cipher_name(options.cipher));
|
|
|
|
|
|
|
|
debug("Encryption type: %.100s", cipher_name(options.cipher));
|
|
|
|
|
|
|
|
/* Send the encrypted session key to the server. */
|
|
|
|
packet_start(SSH_CMSG_SESSION_KEY);
|
|
|
|
packet_put_char(options.cipher);
|
|
|
|
|
|
|
|
/* Send the cookie back to the server. */
|
|
|
|
for (i = 0; i < 8; i++)
|
|
|
|
packet_put_char(cookie[i]);
|
|
|
|
|
|
|
|
/* Send and destroy the encrypted encryption key integer. */
|
|
|
|
packet_put_bignum(key);
|
|
|
|
BN_clear_free(key);
|
|
|
|
|
|
|
|
/* Send protocol flags. */
|
|
|
|
packet_put_int(client_flags);
|
|
|
|
|
|
|
|
/* Send the packet now. */
|
|
|
|
packet_send();
|
|
|
|
packet_write_wait();
|
|
|
|
|
|
|
|
debug("Sent encrypted session key.");
|
|
|
|
|
|
|
|
/* Set the encryption key. */
|
|
|
|
packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, options.cipher);
|
|
|
|
|
|
|
|
/* We will no longer need the session key here. Destroy any extra copies. */
|
|
|
|
memset(session_key, 0, sizeof(session_key));
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Expect a success message from the server. Note that this message
|
|
|
|
* will be received in encrypted form.
|
|
|
|
*/
|
|
|
|
packet_read_expect(&payload_len, SSH_SMSG_SUCCESS);
|
|
|
|
|
|
|
|
debug("Received encrypted confirmation.");
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Authenticate user
|
|
|
|
*/
|
|
|
|
void
|
|
|
|
ssh_userauth(int host_key_valid, RSA *own_host_key,
|
|
|
|
uid_t original_real_uid, char *host)
|
|
|
|
{
|
|
|
|
int i, type;
|
|
|
|
int payload_len;
|
|
|
|
struct passwd *pw;
|
|
|
|
const char *server_user, *local_user;
|
|
|
|
|
|
|
|
/* Get local user name. Use it as server user if no user name was given. */
|
|
|
|
pw = getpwuid(original_real_uid);
|
|
|
|
if (!pw)
|
|
|
|
fatal("User id %d not found from user database.", original_real_uid);
|
|
|
|
local_user = xstrdup(pw->pw_name);
|
|
|
|
server_user = options.user ? options.user : local_user;
|
|
|
|
|
|
|
|
/* Send the name of the user to log in as on the server. */
|
|
|
|
packet_start(SSH_CMSG_USER);
|
|
|
|
packet_put_string(server_user, strlen(server_user));
|
|
|
|
packet_send();
|
|
|
|
packet_write_wait();
|
|
|
|
|
|
|
|
/*
|
|
|
|
* The server should respond with success if no authentication is
|
|
|
|
* needed (the user has no password). Otherwise the server responds
|
|
|
|
* with failure.
|
|
|
|
*/
|
|
|
|
type = packet_read(&payload_len);
|
|
|
|
|
|
|
|
/* check whether the connection was accepted without authentication. */
|
|
|
|
if (type == SSH_SMSG_SUCCESS)
|
|
|
|
return;
|
|
|
|
if (type != SSH_SMSG_FAILURE)
|
|
|
|
packet_disconnect("Protocol error: got %d in response to SSH_CMSG_USER",
|
|
|
|
type);
|
|
|
|
|
|
|
|
#ifdef AFS
|
|
|
|
/* Try Kerberos tgt passing if the server supports it. */
|
2000-02-28 19:03:50 +00:00
|
|
|
if ((supported_authentications & (1 << SSH_PASS_KRB4_TGT)) &&
|
|
|
|
options.krb4_tgt_passing) {
|
2000-02-24 14:29:47 +00:00
|
|
|
if (options.cipher == SSH_CIPHER_NONE)
|
|
|
|
log("WARNING: Encryption is disabled! Ticket will be transmitted in the clear!");
|
2000-02-28 19:03:50 +00:00
|
|
|
(void) send_krb4_tgt();
|
2000-02-24 14:29:47 +00:00
|
|
|
}
|
|
|
|
/* Try AFS token passing if the server supports it. */
|
|
|
|
if ((supported_authentications & (1 << SSH_PASS_AFS_TOKEN)) &&
|
|
|
|
options.afs_token_passing && k_hasafs()) {
|
|
|
|
if (options.cipher == SSH_CIPHER_NONE)
|
|
|
|
log("WARNING: Encryption is disabled! Token will be transmitted in the clear!");
|
|
|
|
send_afs_tokens();
|
|
|
|
}
|
|
|
|
#endif /* AFS */
|
|
|
|
|
|
|
|
#ifdef KRB4
|
2000-02-28 19:03:50 +00:00
|
|
|
if ((supported_authentications & (1 << SSH_AUTH_KRB4)) &&
|
|
|
|
options.krb4_authentication) {
|
2000-02-24 14:29:47 +00:00
|
|
|
debug("Trying Kerberos authentication.");
|
2000-02-28 19:03:50 +00:00
|
|
|
if (try_krb4_authentication()) {
|
2000-02-24 14:29:47 +00:00
|
|
|
/* The server should respond with success or failure. */
|
|
|
|
type = packet_read(&payload_len);
|
|
|
|
if (type == SSH_SMSG_SUCCESS)
|
|
|
|
return;
|
|
|
|
if (type != SSH_SMSG_FAILURE)
|
|
|
|
packet_disconnect("Protocol error: got %d in response to Kerberos auth", type);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
#endif /* KRB4 */
|
|
|
|
|
2000-02-28 19:03:50 +00:00
|
|
|
#ifdef KRB5
|
|
|
|
if ((supported_authentications & (1 << SSH_AUTH_KRB5)) &&
|
|
|
|
options.krb5_authentication){
|
|
|
|
krb5_context ssh_context = NULL;
|
|
|
|
krb5_auth_context auth_context = NULL;
|
|
|
|
|
|
|
|
debug("Trying Kerberos V5 authentication.");
|
|
|
|
|
|
|
|
if (try_krb5_authentication(&ssh_context, &auth_context)) {
|
|
|
|
type = packet_read(&payload_len);
|
|
|
|
if (type == SSH_SMSG_SUCCESS) {
|
|
|
|
if ((supported_authentications & (1 << SSH_PASS_KRB5_TGT)) &&
|
|
|
|
options.krb5_tgt_passing) {
|
|
|
|
if (options.cipher == SSH_CIPHER_NONE)
|
|
|
|
log("WARNING: Encryption is disabled! Ticket will be transmitted in the clear!");
|
|
|
|
send_krb5_tgt(ssh_context, auth_context);
|
|
|
|
|
|
|
|
}
|
|
|
|
krb5_auth_con_free(ssh_context, auth_context);
|
|
|
|
krb5_free_context(ssh_context);
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
if (type != SSH_SMSG_FAILURE)
|
|
|
|
packet_disconnect("Protocol error: got %d in response to Kerberos5 auth", type);
|
|
|
|
|
|
|
|
}
|
|
|
|
}
|
|
|
|
#endif /* KRB5 */
|
|
|
|
|
2000-02-24 14:29:47 +00:00
|
|
|
/*
|
|
|
|
* Use rhosts authentication if running in privileged socket and we
|
|
|
|
* do not wish to remain anonymous.
|
|
|
|
*/
|
|
|
|
if ((supported_authentications & (1 << SSH_AUTH_RHOSTS)) &&
|
|
|
|
options.rhosts_authentication) {
|
|
|
|
debug("Trying rhosts authentication.");
|
|
|
|
packet_start(SSH_CMSG_AUTH_RHOSTS);
|
|
|
|
packet_put_string(local_user, strlen(local_user));
|
|
|
|
packet_send();
|
|
|
|
packet_write_wait();
|
|
|
|
|
|
|
|
/* The server should respond with success or failure. */
|
|
|
|
type = packet_read(&payload_len);
|
|
|
|
if (type == SSH_SMSG_SUCCESS)
|
|
|
|
return;
|
|
|
|
if (type != SSH_SMSG_FAILURE)
|
|
|
|
packet_disconnect("Protocol error: got %d in response to rhosts auth",
|
|
|
|
type);
|
|
|
|
}
|
|
|
|
/*
|
|
|
|
* Try .rhosts or /etc/hosts.equiv authentication with RSA host
|
|
|
|
* authentication.
|
|
|
|
*/
|
|
|
|
if ((supported_authentications & (1 << SSH_AUTH_RHOSTS_RSA)) &&
|
|
|
|
options.rhosts_rsa_authentication && host_key_valid) {
|
|
|
|
if (try_rhosts_rsa_authentication(local_user, own_host_key))
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
/* Try RSA authentication if the server supports it. */
|
|
|
|
if ((supported_authentications & (1 << SSH_AUTH_RSA)) &&
|
|
|
|
options.rsa_authentication) {
|
|
|
|
/*
|
|
|
|
* Try RSA authentication using the authentication agent. The
|
|
|
|
* agent is tried first because no passphrase is needed for
|
|
|
|
* it, whereas identity files may require passphrases.
|
|
|
|
*/
|
|
|
|
if (try_agent_authentication())
|
|
|
|
return;
|
|
|
|
|
|
|
|
/* Try RSA authentication for each identity. */
|
|
|
|
for (i = 0; i < options.num_identity_files; i++)
|
|
|
|
if (try_rsa_authentication(options.identity_files[i]))
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
/* Try skey authentication if the server supports it. */
|
|
|
|
if ((supported_authentications & (1 << SSH_AUTH_TIS)) &&
|
|
|
|
options.skey_authentication && !options.batch_mode) {
|
|
|
|
if (try_skey_authentication())
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
/* Try password authentication if the server supports it. */
|
|
|
|
if ((supported_authentications & (1 << SSH_AUTH_PASSWORD)) &&
|
|
|
|
options.password_authentication && !options.batch_mode) {
|
|
|
|
char prompt[80];
|
|
|
|
|
|
|
|
snprintf(prompt, sizeof(prompt), "%.30s@%.40s's password: ",
|
|
|
|
server_user, host);
|
|
|
|
if (try_password_authentication(prompt))
|
|
|
|
return;
|
|
|
|
}
|
|
|
|
/* All authentication methods have failed. Exit with an error message. */
|
|
|
|
fatal("Permission denied.");
|
|
|
|
/* NOTREACHED */
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Starts a dialog with the server, and authenticates the current user on the
|
|
|
|
* server. This does not need any extra privileges. The basic connection
|
|
|
|
* to the server must already have been established before this is called.
|
|
|
|
* If login fails, this function prints an error and never returns.
|
|
|
|
* This function does not require super-user privileges.
|
|
|
|
*/
|
|
|
|
void
|
|
|
|
ssh_login(int host_key_valid, RSA *own_host_key, const char *orighost,
|
|
|
|
struct sockaddr *hostaddr, uid_t original_real_uid)
|
|
|
|
{
|
|
|
|
char *host, *cp;
|
|
|
|
|
|
|
|
/* Convert the user-supplied hostname into all lowercase. */
|
|
|
|
host = xstrdup(orighost);
|
|
|
|
for (cp = host; *cp; cp++)
|
|
|
|
if (isupper(*cp))
|
|
|
|
*cp = tolower(*cp);
|
|
|
|
|
|
|
|
/* Exchange protocol version identification strings with the server. */
|
|
|
|
ssh_exchange_identification();
|
|
|
|
|
|
|
|
/* Put the connection into non-blocking mode. */
|
|
|
|
packet_set_nonblocking();
|
|
|
|
|
|
|
|
supported_authentications = 0;
|
|
|
|
/* key exchange */
|
|
|
|
ssh_kex(host, hostaddr);
|
|
|
|
if (supported_authentications == 0)
|
|
|
|
fatal("supported_authentications == 0.");
|
|
|
|
/* authenticate user */
|
|
|
|
ssh_userauth(host_key_valid, own_host_key, original_real_uid, host);
|
|
|
|
}
|