freebsd-skq/crypto/openssh/sshconnect.c

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/* $OpenBSD: sshconnect.c,v 1.246 2014/02/06 22:21:01 djm Exp $ */
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/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
* Code to connect to a remote host, and to perform the client side of the
* login (authentication) dialog.
*
* As far as I am concerned, the code I have written for this software
* can be used freely for any purpose. Any derived versions of this
* software must be clearly marked as such, and if the derived work is
* incompatible with the protocol description in the RFC file, it must be
* called by a name other than "ssh" or "Secure Shell".
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*/
#include "includes.h"
__RCSID("$FreeBSD$");
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#include <sys/types.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <sys/socket.h>
#ifdef HAVE_SYS_TIME_H
# include <sys/time.h>
#endif
#include <netinet/in.h>
#include <arpa/inet.h>
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#include <rpc/rpc.h>
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#include <ctype.h>
#include <errno.h>
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#include <fcntl.h>
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#include <netdb.h>
#ifdef HAVE_PATHS_H
#include <paths.h>
#endif
#include <pwd.h>
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#include <signal.h>
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#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
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#include "xmalloc.h"
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#include "key.h"
#include "hostfile.h"
#include "ssh.h"
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#include "rsa.h"
#include "buffer.h"
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#include "packet.h"
#include "uidswap.h"
#include "compat.h"
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#include "key.h"
#include "sshconnect.h"
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#include "hostfile.h"
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#include "log.h"
#include "readconf.h"
#include "atomicio.h"
#include "misc.h"
#include "dns.h"
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#include "roaming.h"
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#include "monitor_fdpass.h"
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#include "ssh2.h"
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#include "version.h"
char *client_version_string = NULL;
char *server_version_string = NULL;
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static int matching_host_key_dns = 0;
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static pid_t proxy_command_pid = 0;
/* import */
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extern Options options;
extern char *__progname;
extern uid_t original_real_uid;
extern uid_t original_effective_uid;
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static int show_other_keys(struct hostkeys *, Key *);
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static void warn_changed_key(Key *);
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/* Expand a proxy command */
static char *
expand_proxy_command(const char *proxy_command, const char *user,
const char *host, int port)
{
char *tmp, *ret, strport[NI_MAXSERV];
snprintf(strport, sizeof strport, "%d", port);
xasprintf(&tmp, "exec %s", proxy_command);
ret = percent_expand(tmp, "h", host, "p", strport,
"r", options.user, (char *)NULL);
free(tmp);
return ret;
}
/*
* Connect to the given ssh server using a proxy command that passes a
* a connected fd back to us.
*/
static int
ssh_proxy_fdpass_connect(const char *host, u_short port,
const char *proxy_command)
{
char *command_string;
int sp[2], sock;
pid_t pid;
char *shell;
if ((shell = getenv("SHELL")) == NULL)
shell = _PATH_BSHELL;
if (socketpair(AF_UNIX, SOCK_STREAM, 0, sp) < 0)
fatal("Could not create socketpair to communicate with "
"proxy dialer: %.100s", strerror(errno));
command_string = expand_proxy_command(proxy_command, options.user,
host, port);
debug("Executing proxy dialer command: %.500s", command_string);
/* Fork and execute the proxy command. */
if ((pid = fork()) == 0) {
char *argv[10];
/* Child. Permanently give up superuser privileges. */
permanently_drop_suid(original_real_uid);
close(sp[1]);
/* Redirect stdin and stdout. */
if (sp[0] != 0) {
if (dup2(sp[0], 0) < 0)
perror("dup2 stdin");
}
if (sp[0] != 1) {
if (dup2(sp[0], 1) < 0)
perror("dup2 stdout");
}
if (sp[0] >= 2)
close(sp[0]);
/*
* Stderr is left as it is so that error messages get
* printed on the user's terminal.
*/
argv[0] = shell;
argv[1] = "-c";
argv[2] = command_string;
argv[3] = NULL;
/*
* Execute the proxy command.
* Note that we gave up any extra privileges above.
*/
execv(argv[0], argv);
perror(argv[0]);
exit(1);
}
/* Parent. */
if (pid < 0)
fatal("fork failed: %.100s", strerror(errno));
close(sp[0]);
free(command_string);
if ((sock = mm_receive_fd(sp[1])) == -1)
fatal("proxy dialer did not pass back a connection");
while (waitpid(pid, NULL, 0) == -1)
if (errno != EINTR)
fatal("Couldn't wait for child: %s", strerror(errno));
/* Set the connection file descriptors. */
packet_set_connection(sock, sock);
return 0;
}
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/*
* Connect to the given ssh server using a proxy command.
*/
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static int
ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
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{
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char *command_string;
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int pin[2], pout[2];
pid_t pid;
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char *shell;
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if ((shell = getenv("SHELL")) == NULL || *shell == '\0')
shell = _PATH_BSHELL;
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/* Create pipes for communicating with the proxy. */
if (pipe(pin) < 0 || pipe(pout) < 0)
fatal("Could not create pipes to communicate with the proxy: %.100s",
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strerror(errno));
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command_string = expand_proxy_command(proxy_command, options.user,
host, port);
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debug("Executing proxy command: %.500s", command_string);
/* Fork and execute the proxy command. */
if ((pid = fork()) == 0) {
char *argv[10];
/* Child. Permanently give up superuser privileges. */
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permanently_drop_suid(original_real_uid);
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/* Redirect stdin and stdout. */
close(pin[1]);
if (pin[0] != 0) {
if (dup2(pin[0], 0) < 0)
perror("dup2 stdin");
close(pin[0]);
}
close(pout[0]);
if (dup2(pout[1], 1) < 0)
perror("dup2 stdout");
/* Cannot be 1 because pin allocated two descriptors. */
close(pout[1]);
/* Stderr is left as it is so that error messages get
printed on the user's terminal. */
argv[0] = shell;
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argv[1] = "-c";
argv[2] = command_string;
argv[3] = NULL;
/* Execute the proxy command. Note that we gave up any
extra privileges above. */
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signal(SIGPIPE, SIG_DFL);
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execv(argv[0], argv);
perror(argv[0]);
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exit(1);
}
/* Parent. */
if (pid < 0)
fatal("fork failed: %.100s", strerror(errno));
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else
proxy_command_pid = pid; /* save pid to clean up later */
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/* Close child side of the descriptors. */
close(pin[0]);
close(pout[1]);
/* Free the command name. */
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free(command_string);
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/* Set the connection file descriptors. */
packet_set_connection(pout[0], pin[1]);
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/* Indicate OK return */
return 0;
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}
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void
ssh_kill_proxy_command(void)
{
/*
* Send SIGHUP to proxy command if used. We don't wait() in
* case it hangs and instead rely on init to reap the child
*/
if (proxy_command_pid > 1)
kill(proxy_command_pid, SIGHUP);
}
/*
* Set TCP receive buffer if requested.
* Note: tuning needs to happen after the socket is created but before the
* connection happens so winscale is negotiated properly.
*/
static void
ssh_set_socket_recvbuf(int sock)
{
void *buf = (void *)&options.tcp_rcv_buf;
int socksize, sz = sizeof(options.tcp_rcv_buf);
socklen_t len = sizeof(int);
debug("setsockopt attempting to set SO_RCVBUF to %d",
options.tcp_rcv_buf);
if (setsockopt(sock, SOL_SOCKET, SO_RCVBUF, buf, sz) >= 0) {
getsockopt(sock, SOL_SOCKET, SO_RCVBUF, &socksize, &len);
debug("setsockopt SO_RCVBUF: %.100s %d", strerror(errno),
socksize);
} else
error("Couldn't set socket receive buffer to %d: %.100s",
options.tcp_rcv_buf, strerror(errno));
}
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/*
* Creates a (possibly privileged) socket for use as the ssh connection.
*/
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static int
ssh_create_socket(int privileged, struct addrinfo *ai)
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{
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int sock, r, gaierr;
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struct addrinfo hints, *res = NULL;
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sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
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if (sock < 0) {
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error("socket: %s", strerror(errno));
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return -1;
}
fcntl(sock, F_SETFD, FD_CLOEXEC);
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if (options.tcp_rcv_buf > 0)
ssh_set_socket_recvbuf(sock);
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/* Bind the socket to an alternative local IP address */
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if (options.bind_address == NULL && !privileged)
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return sock;
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if (options.bind_address) {
memset(&hints, 0, sizeof(hints));
hints.ai_family = ai->ai_family;
hints.ai_socktype = ai->ai_socktype;
hints.ai_protocol = ai->ai_protocol;
hints.ai_flags = AI_PASSIVE;
gaierr = getaddrinfo(options.bind_address, NULL, &hints, &res);
if (gaierr) {
error("getaddrinfo: %s: %s", options.bind_address,
ssh_gai_strerror(gaierr));
close(sock);
return -1;
}
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}
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/*
* If we are running as root and want to connect to a privileged
* port, bind our own socket to a privileged port.
*/
if (privileged) {
PRIV_START;
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r = bindresvport_sa(sock, res ? res->ai_addr : NULL);
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PRIV_END;
if (r < 0) {
error("bindresvport_sa: af=%d %s", ai->ai_family,
strerror(errno));
goto fail;
}
} else {
if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
error("bind: %s: %s", options.bind_address,
strerror(errno));
fail:
close(sock);
freeaddrinfo(res);
return -1;
}
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}
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if (res != NULL)
freeaddrinfo(res);
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return sock;
}
static int
timeout_connect(int sockfd, const struct sockaddr *serv_addr,
socklen_t addrlen, int *timeoutp)
{
fd_set *fdset;
struct timeval tv, t_start;
socklen_t optlen;
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int optval, rc, result = -1;
gettimeofday(&t_start, NULL);
if (*timeoutp <= 0) {
result = connect(sockfd, serv_addr, addrlen);
goto done;
}
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set_nonblock(sockfd);
rc = connect(sockfd, serv_addr, addrlen);
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if (rc == 0) {
unset_nonblock(sockfd);
result = 0;
goto done;
}
if (errno != EINPROGRESS) {
result = -1;
goto done;
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}
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fdset = (fd_set *)xcalloc(howmany(sockfd + 1, NFDBITS),
sizeof(fd_mask));
FD_SET(sockfd, fdset);
ms_to_timeval(&tv, *timeoutp);
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for (;;) {
rc = select(sockfd + 1, NULL, fdset, NULL, &tv);
if (rc != -1 || errno != EINTR)
break;
}
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switch (rc) {
case 0:
/* Timed out */
errno = ETIMEDOUT;
break;
case -1:
/* Select error */
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debug("select: %s", strerror(errno));
break;
case 1:
/* Completed or failed */
optval = 0;
optlen = sizeof(optval);
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if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval,
&optlen) == -1) {
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debug("getsockopt: %s", strerror(errno));
break;
}
if (optval != 0) {
errno = optval;
break;
}
result = 0;
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unset_nonblock(sockfd);
break;
default:
/* Should not occur */
fatal("Bogus return (%d) from select()", rc);
}
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free(fdset);
done:
if (result == 0 && *timeoutp > 0) {
ms_subtract_diff(&t_start, timeoutp);
if (*timeoutp <= 0) {
errno = ETIMEDOUT;
result = -1;
}
}
return (result);
}
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/*
* Opens a TCP/IP connection to the remote server on the given host.
* The address of the remote host will be returned in hostaddr.
* If port is 0, the default port will be used. If needpriv is true,
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* a privileged port will be allocated to make the connection.
* This requires super-user privileges if needpriv is true.
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* Connection_attempts specifies the maximum number of tries (one per
* second). If proxy_command is non-NULL, it specifies the command (with %h
* and %p substituted for host and port, respectively) to use to contact
* the daemon.
*/
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static int
ssh_connect_direct(const char *host, struct addrinfo *aitop,
struct sockaddr_storage *hostaddr, u_short port, int family,
int connection_attempts, int *timeout_ms, int want_keepalive, int needpriv)
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{
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int on = 1;
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int sock = -1, attempt;
char ntop[NI_MAXHOST], strport[NI_MAXSERV];
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struct addrinfo *ai;
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debug2("ssh_connect: needpriv %d", needpriv);
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for (attempt = 0; attempt < connection_attempts; attempt++) {
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if (attempt > 0) {
/* Sleep a moment before retrying. */
sleep(1);
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debug("Trying again...");
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}
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/*
* Loop through addresses for this host, and try each one in
* 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;
if (getnameinfo(ai->ai_addr, ai->ai_addrlen,
ntop, sizeof(ntop), strport, sizeof(strport),
NI_NUMERICHOST|NI_NUMERICSERV) != 0) {
error("ssh_connect: getnameinfo failed");
continue;
}
debug("Connecting to %.200s [%.100s] port %s.",
host, ntop, strport);
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/* Create a socket for connecting. */
sock = ssh_create_socket(needpriv, ai);
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if (sock < 0)
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/* Any error is already output */
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continue;
if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen,
timeout_ms) >= 0) {
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/* Successful connection. */
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memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
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break;
} else {
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debug("connect to address %s port %s: %s",
ntop, strport, strerror(errno));
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close(sock);
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sock = -1;
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}
}
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if (sock != -1)
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break; /* Successful connection. */
}
/* Return failure if we didn't get a successful connection. */
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if (sock == -1) {
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error("ssh: connect to host %s port %s: %s",
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host, strport, strerror(errno));
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return (-1);
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}
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debug("Connection established.");
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/* Set SO_KEEPALIVE if requested. */
if (want_keepalive &&
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setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
sizeof(on)) < 0)
error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
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/* Set the connection. */
packet_set_connection(sock, sock);
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return 0;
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}
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int
ssh_connect(const char *host, struct addrinfo *addrs,
struct sockaddr_storage *hostaddr, u_short port, int family,
int connection_attempts, int *timeout_ms, int want_keepalive, int needpriv)
{
if (options.proxy_command == NULL) {
return ssh_connect_direct(host, addrs, hostaddr, port, family,
connection_attempts, timeout_ms, want_keepalive, needpriv);
} else if (strcmp(options.proxy_command, "-") == 0) {
packet_set_connection(STDIN_FILENO, STDOUT_FILENO);
return 0; /* Always succeeds */
} else if (options.proxy_use_fdpass) {
return ssh_proxy_fdpass_connect(host, port,
options.proxy_command);
}
return ssh_proxy_connect(host, port, options.proxy_command);
}
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static void
send_client_banner(int connection_out, int minor1)
{
/* Send our own protocol version identification. */
xasprintf(&client_version_string, "SSH-%d.%d-%.100s%s%s%s%s",
compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
compat20 ? PROTOCOL_MINOR_2 : minor1,
SSH_VERSION, options.hpn_disabled ? "" : SSH_VERSION_HPN,
*options.version_addendum == '\0' ? "" : " ",
options.version_addendum, compat20 ? "\r\n" : "\n");
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if (roaming_atomicio(vwrite, connection_out, client_version_string,
strlen(client_version_string)) != strlen(client_version_string))
fatal("write: %.100s", strerror(errno));
chop(client_version_string);
debug("Local version string %.100s", client_version_string);
}
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/*
* Waits for the server identification string, and sends our own
* identification string.
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*/
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void
ssh_exchange_identification(int timeout_ms)
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{
char buf[256], remote_version[256]; /* must be same size! */
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int remote_major, remote_minor, mismatch;
int connection_in = packet_get_connection_in();
int connection_out = packet_get_connection_out();
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int minor1 = PROTOCOL_MINOR_1, client_banner_sent = 0;
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u_int i, n;
size_t len;
int fdsetsz, remaining, rc;
struct timeval t_start, t_remaining;
fd_set *fdset;
fdsetsz = howmany(connection_in + 1, NFDBITS) * sizeof(fd_mask);
fdset = xcalloc(1, fdsetsz);
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/*
* If we are SSH2-only then we can send the banner immediately and
* save a round-trip.
*/
if (options.protocol == SSH_PROTO_2) {
enable_compat20();
send_client_banner(connection_out, 0);
client_banner_sent = 1;
}
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/* Read other side's version identification. */
remaining = timeout_ms;
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for (n = 0;;) {
for (i = 0; i < sizeof(buf) - 1; i++) {
if (timeout_ms > 0) {
gettimeofday(&t_start, NULL);
ms_to_timeval(&t_remaining, remaining);
FD_SET(connection_in, fdset);
rc = select(connection_in + 1, fdset, NULL,
fdset, &t_remaining);
ms_subtract_diff(&t_start, &remaining);
if (rc == 0 || remaining <= 0)
fatal("Connection timed out during "
"banner exchange");
if (rc == -1) {
if (errno == EINTR)
continue;
fatal("ssh_exchange_identification: "
"select: %s", strerror(errno));
}
}
2009-10-01 15:19:37 +00:00
len = roaming_atomicio(read, connection_in, &buf[i], 1);
2005-09-03 07:04:25 +00:00
if (len != 1 && errno == EPIPE)
fatal("ssh_exchange_identification: "
"Connection closed by remote host");
2005-09-03 07:04:25 +00:00
else if (len != 1)
fatal("ssh_exchange_identification: "
"read: %.100s", strerror(errno));
if (buf[i] == '\r') {
buf[i] = '\n';
buf[i + 1] = 0;
continue; /**XXX wait for \n */
}
if (buf[i] == '\n') {
buf[i + 1] = 0;
break;
}
2006-09-30 13:38:06 +00:00
if (++n > 65536)
fatal("ssh_exchange_identification: "
"No banner received");
}
buf[sizeof(buf) - 1] = 0;
if (strncmp(buf, "SSH-", 4) == 0)
break;
debug("ssh_exchange_identification: %s", buf);
2000-02-24 14:29:47 +00:00
}
server_version_string = xstrdup(buf);
2013-09-18 17:27:38 +00:00
free(fdset);
2000-02-24 14:29:47 +00:00
/*
* Check that the versions match. In future this might accept
* several versions and set appropriate flags to handle them.
2000-02-24 14:29:47 +00:00
*/
if (sscanf(server_version_string, "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",
2002-03-18 10:09:43 +00:00
remote_major, remote_minor, remote_version);
2000-02-24 14:29:47 +00:00
compat_datafellows(remote_version);
mismatch = 0;
2000-02-24 14:29:47 +00:00
2002-03-18 10:09:43 +00:00
switch (remote_major) {
case 1:
if (remote_minor == 99 &&
(options.protocol & SSH_PROTO_2) &&
!(options.protocol & SSH_PROTO_1_PREFERRED)) {
enable_compat20();
break;
2000-02-24 14:29:47 +00:00
}
if (!(options.protocol & SSH_PROTO_1)) {
mismatch = 1;
break;
2000-02-24 14:29:47 +00:00
}
if (remote_minor < 3) {
fatal("Remote machine has too old SSH software version.");
2001-05-04 04:14:23 +00:00
} else if (remote_minor == 3 || remote_minor == 4) {
/* We speak 1.3, too. */
enable_compat13();
2001-05-04 04:14:23 +00:00
minor1 = 3;
if (options.forward_agent) {
logit("Agent forwarding disabled for protocol 1.3");
options.forward_agent = 0;
}
}
break;
case 2:
if (options.protocol & SSH_PROTO_2) {
enable_compat20();
break;
}
/* FALLTHROUGH */
default:
mismatch = 1;
break;
2000-02-24 14:29:47 +00:00
}
if (mismatch)
fatal("Protocol major versions differ: %d vs. %d",
(options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
remote_major);
2014-01-30 10:56:49 +00:00
if ((datafellows & SSH_BUG_DERIVEKEY) != 0)
fatal("Server version \"%.100s\" uses unsafe key agreement; "
"refusing connection", remote_version);
if ((datafellows & SSH_BUG_RSASIGMD5) != 0)
logit("Server version \"%.100s\" uses unsafe RSA signature "
"scheme; disabling use of RSA keys", remote_version);
2013-03-22 11:19:48 +00:00
if (!client_banner_sent)
send_client_banner(connection_out, minor1);
chop(server_version_string);
2000-02-24 14:29:47 +00:00
}
2001-05-04 04:14:23 +00:00
/* defaults to 'no' */
2002-03-18 10:09:43 +00:00
static int
confirm(const char *prompt)
2000-02-24 14:29:47 +00:00
{
2002-03-18 10:09:43 +00:00
const char *msg, *again = "Please type 'yes' or 'no': ";
char *p;
int ret = -1;
2000-02-24 14:29:47 +00:00
2001-05-04 04:14:23 +00:00
if (options.batch_mode)
return 0;
2002-03-18 10:09:43 +00:00
for (msg = prompt;;msg = again) {
p = read_passphrase(msg, RP_ECHO);
if (p == NULL ||
(p[0] == '\0') || (p[0] == '\n') ||
strncasecmp(p, "no", 2) == 0)
ret = 0;
2002-10-29 10:16:02 +00:00
if (p && strncasecmp(p, "yes", 3) == 0)
2002-03-18 10:09:43 +00:00
ret = 1;
2013-09-18 17:27:38 +00:00
free(p);
2002-03-18 10:09:43 +00:00
if (ret != -1)
return ret;
2000-02-24 14:29:47 +00:00
}
}
2010-03-08 11:19:52 +00:00
static int
check_host_cert(const char *host, const Key *host_key)
{
const char *reason;
if (key_cert_check_authority(host_key, 1, 0, host, &reason) != 0) {
error("%s", reason);
return 0;
}
2010-11-08 10:45:44 +00:00
if (buffer_len(&host_key->cert->critical) != 0) {
error("Certificate for %s contains unsupported "
"critical options(s)", host);
2010-03-08 11:19:52 +00:00
return 0;
}
return 1;
}
2011-02-17 11:47:40 +00:00
static int
sockaddr_is_local(struct sockaddr *hostaddr)
{
switch (hostaddr->sa_family) {
case AF_INET:
return (ntohl(((struct sockaddr_in *)hostaddr)->
sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
case AF_INET6:
return IN6_IS_ADDR_LOOPBACK(
&(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
default:
return 0;
}
}
/*
* Prepare the hostname and ip address strings that are used to lookup
* host keys in known_hosts files. These may have a port number appended.
*/
void
get_hostfile_hostname_ipaddr(char *hostname, struct sockaddr *hostaddr,
u_short port, char **hostfile_hostname, char **hostfile_ipaddr)
{
char ntop[NI_MAXHOST];
socklen_t addrlen;
switch (hostaddr == NULL ? -1 : hostaddr->sa_family) {
case -1:
addrlen = 0;
break;
case AF_INET:
addrlen = sizeof(struct sockaddr_in);
break;
case AF_INET6:
addrlen = sizeof(struct sockaddr_in6);
break;
default:
addrlen = sizeof(struct sockaddr);
break;
}
/*
* We don't have the remote ip-address for connections
* using a proxy command
*/
if (hostfile_ipaddr != NULL) {
if (options.proxy_command == NULL) {
if (getnameinfo(hostaddr, addrlen,
ntop, sizeof(ntop), NULL, 0, NI_NUMERICHOST) != 0)
fatal("check_host_key: getnameinfo failed");
*hostfile_ipaddr = put_host_port(ntop, port);
} else {
*hostfile_ipaddr = xstrdup("<no hostip for proxy "
"command>");
}
}
/*
* Allow the user to record the key under a different name or
* differentiate a non-standard port. This is useful for ssh
* tunneling over forwarded connections or if you run multiple
* sshd's on different ports on the same machine.
*/
if (hostfile_hostname != NULL) {
if (options.host_key_alias != NULL) {
*hostfile_hostname = xstrdup(options.host_key_alias);
debug("using hostkeyalias: %s", *hostfile_hostname);
} else {
*hostfile_hostname = put_host_port(hostname, port);
}
}
}
/*
2002-03-18 10:09:43 +00:00
* check whether the supplied host key is valid, return -1 if the key
2011-09-28 08:14:41 +00:00
* is not valid. user_hostfile[0] will not be updated if 'readonly' is true.
*/
2006-09-30 13:38:06 +00:00
#define RDRW 0
#define RDONLY 1
#define ROQUIET 2
2002-03-18 10:09:43 +00:00
static int
2006-09-30 13:38:06 +00:00
check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port,
2011-09-28 08:14:41 +00:00
Key *host_key, int readonly,
char **user_hostfiles, u_int num_user_hostfiles,
char **system_hostfiles, u_int num_system_hostfiles)
{
2011-09-28 08:14:41 +00:00
HostStatus host_status;
HostStatus ip_status;
2011-02-17 11:47:40 +00:00
Key *raw_key = NULL;
2006-09-30 13:38:06 +00:00
char *ip = NULL, *host = NULL;
2008-07-23 09:33:08 +00:00
char hostline[1000], *hostp, *fp, *ra;
2002-03-18 10:09:43 +00:00
char msg[1024];
2011-09-28 08:14:41 +00:00
const char *type;
const struct hostkey_entry *host_found, *ip_found;
2011-02-17 11:47:40 +00:00
int len, cancelled_forwarding = 0;
2011-09-28 08:14:41 +00:00
int local = sockaddr_is_local(hostaddr);
int r, want_cert = key_is_cert(host_key), host_ip_differ = 0;
2011-02-17 11:47:40 +00:00
struct hostkeys *host_hostkeys, *ip_hostkeys;
2011-09-28 08:14:41 +00:00
u_int i;
2000-02-24 14:29:47 +00:00
/*
* 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.
*/
2002-03-18 10:09:43 +00:00
if (options.no_host_authentication_for_localhost == 1 && local &&
options.host_key_alias == NULL) {
2001-05-04 04:14:23 +00:00
debug("Forcing accepting of host key for "
"loopback/localhost.");
2002-03-18 10:09:43 +00:00
return 0;
2000-02-24 14:29:47 +00:00
}
/*
2011-02-17 11:47:40 +00:00
* Prepare the hostname and address strings used for hostkey lookup.
* In some cases, these will have a port number appended.
*/
2011-02-17 11:47:40 +00:00
get_hostfile_hostname_ipaddr(hostname, hostaddr, port, &host, &ip);
2008-07-23 09:33:08 +00:00
2001-05-04 04:14:23 +00:00
/*
* Turn off check_host_ip if the connection is to localhost, via proxy
* command or if we don't have a hostname to compare with
*/
2006-09-30 13:38:06 +00:00
if (options.check_host_ip && (local ||
strcmp(hostname, ip) == 0 || options.proxy_command != NULL))
2001-05-04 04:14:23 +00:00
options.check_host_ip = 0;
2011-02-17 11:47:40 +00:00
host_hostkeys = init_hostkeys();
2011-09-28 08:14:41 +00:00
for (i = 0; i < num_user_hostfiles; i++)
load_hostkeys(host_hostkeys, host, user_hostfiles[i]);
for (i = 0; i < num_system_hostfiles; i++)
load_hostkeys(host_hostkeys, host, system_hostfiles[i]);
2011-02-17 11:47:40 +00:00
ip_hostkeys = NULL;
if (!want_cert && options.check_host_ip) {
ip_hostkeys = init_hostkeys();
2011-09-28 08:14:41 +00:00
for (i = 0; i < num_user_hostfiles; i++)
load_hostkeys(ip_hostkeys, ip, user_hostfiles[i]);
for (i = 0; i < num_system_hostfiles; i++)
load_hostkeys(ip_hostkeys, ip, system_hostfiles[i]);
2000-02-24 14:29:47 +00:00
}
2010-03-08 11:19:52 +00:00
retry:
2011-02-17 11:47:40 +00:00
/* Reload these as they may have changed on cert->key downgrade */
2010-03-08 11:19:52 +00:00
want_cert = key_is_cert(host_key);
type = key_type(host_key);
/*
2006-03-22 20:41:37 +00:00
* Check if the host key is present in the user's list of known
* hosts or in the systemwide list.
*/
2011-02-17 11:47:40 +00:00
host_status = check_key_in_hostkeys(host_hostkeys, host_key,
&host_found);
/*
* Also perform check for the ip address, skip the check if we are
2010-03-08 11:19:52 +00:00
* localhost, looking for a certificate, or the hostname was an ip
* address to begin with.
*/
2011-02-17 11:47:40 +00:00
if (!want_cert && ip_hostkeys != NULL) {
ip_status = check_key_in_hostkeys(ip_hostkeys, host_key,
&ip_found);
if (host_status == HOST_CHANGED &&
2011-02-17 11:47:40 +00:00
(ip_status != HOST_CHANGED ||
(ip_found != NULL &&
!key_equal(ip_found->key, host_found->key))))
host_ip_differ = 1;
} else
ip_status = host_status;
2000-02-24 14:29:47 +00:00
switch (host_status) {
case HOST_OK:
/* The host is known and the key matches. */
2010-03-08 11:19:52 +00:00
debug("Host '%.200s' is known and matches the %s host %s.",
host, type, want_cert ? "certificate" : "key");
2011-02-17 11:47:40 +00:00
debug("Found %s in %s:%lu", want_cert ? "CA key" : "key",
host_found->file, host_found->line);
2010-03-08 11:19:52 +00:00
if (want_cert && !check_host_cert(hostname, host_key))
goto fail;
2001-05-04 04:14:23 +00:00
if (options.check_host_ip && ip_status == HOST_NEW) {
2010-03-08 11:19:52 +00:00
if (readonly || want_cert)
logit("%s host key for IP address "
2002-03-18 10:09:43 +00:00
"'%.128s' not in list of known hosts.",
2001-05-04 04:14:23 +00:00
type, ip);
2011-09-28 08:14:41 +00:00
else if (!add_host_to_hostfile(user_hostfiles[0], ip,
2005-06-05 15:46:09 +00:00
host_key, options.hash_known_hosts))
logit("Failed to add the %s host key for IP "
2002-03-18 10:09:43 +00:00
"address '%.128s' to the list of known "
2011-09-28 08:14:41 +00:00
"hosts (%.30s).", type, ip,
user_hostfiles[0]);
2002-03-18 10:09:43 +00:00
else
logit("Warning: Permanently added the %s host "
2002-03-18 10:09:43 +00:00
"key for IP address '%.128s' to the list "
"of known hosts.", type, ip);
2008-07-23 09:33:08 +00:00
} else if (options.visual_host_key) {
fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
ra = key_fingerprint(host_key, SSH_FP_MD5,
SSH_FP_RANDOMART);
logit("Host key fingerprint is %s\n%s\n", fp, ra);
2013-09-18 17:27:38 +00:00
free(ra);
free(fp);
}
break;
case HOST_NEW:
2006-09-30 13:38:06 +00:00
if (options.host_key_alias == NULL && port != 0 &&
port != SSH_DEFAULT_PORT) {
debug("checking without port identifier");
2009-02-24 18:49:27 +00:00
if (check_host_key(hostname, hostaddr, 0, host_key,
2011-09-28 08:14:41 +00:00
ROQUIET, user_hostfiles, num_user_hostfiles,
system_hostfiles, num_system_hostfiles) == 0) {
2006-09-30 13:38:06 +00:00
debug("found matching key w/out port");
break;
}
}
2010-03-08 11:19:52 +00:00
if (readonly || want_cert)
2002-03-18 10:09:43 +00:00
goto fail;
/* The host is new. */
if (options.strict_host_key_checking == 1) {
2002-03-18 10:09:43 +00:00
/*
* User has requested strict host key checking. We
* will not add the host key automatically. The only
* alternative left is to abort.
*/
error("No %s host key is known for %.200s and you "
"have requested strict checking.", type, host);
goto fail;
} else if (options.strict_host_key_checking == 2) {
char msg1[1024], msg2[1024];
2011-02-17 11:47:40 +00:00
if (show_other_keys(host_hostkeys, host_key))
snprintf(msg1, sizeof(msg1),
2005-09-03 07:04:25 +00:00
"\nbut keys of different type are already"
" known for this host.");
else
snprintf(msg1, sizeof(msg1), ".");
/* The default */
2001-05-04 04:14:23 +00:00
fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
2008-07-23 09:33:08 +00:00
ra = key_fingerprint(host_key, SSH_FP_MD5,
SSH_FP_RANDOMART);
msg2[0] = '\0';
if (options.verify_host_key_dns) {
2004-02-26 10:52:33 +00:00
if (matching_host_key_dns)
snprintf(msg2, sizeof(msg2),
"Matching host key fingerprint"
" found in DNS.\n");
else
snprintf(msg2, sizeof(msg2),
"No matching host key fingerprint"
" found in DNS.\n");
}
2002-03-18 10:09:43 +00:00
snprintf(msg, sizeof(msg),
"The authenticity of host '%.200s (%s)' can't be "
2002-10-29 10:16:02 +00:00
"established%s\n"
2008-07-23 09:33:08 +00:00
"%s key fingerprint is %s.%s%s\n%s"
2002-03-18 10:09:43 +00:00
"Are you sure you want to continue connecting "
2002-10-29 10:16:02 +00:00
"(yes/no)? ",
2008-07-23 09:33:08 +00:00
host, ip, msg1, type, fp,
options.visual_host_key ? "\n" : "",
options.visual_host_key ? ra : "",
msg2);
2013-09-18 17:27:38 +00:00
free(ra);
free(fp);
2002-03-18 10:09:43 +00:00
if (!confirm(msg))
goto fail;
}
2002-03-18 10:09:43 +00:00
/*
* If not in strict mode, add the key automatically to the
* local known_hosts file.
*/
2005-06-05 15:46:09 +00:00
if (options.check_host_ip && ip_status == HOST_NEW) {
2011-02-17 11:47:40 +00:00
snprintf(hostline, sizeof(hostline), "%s,%s", host, ip);
2005-06-05 15:46:09 +00:00
hostp = hostline;
if (options.hash_known_hosts) {
/* Add hash of host and IP separately */
2011-09-28 08:14:41 +00:00
r = add_host_to_hostfile(user_hostfiles[0],
host, host_key, options.hash_known_hosts) &&
add_host_to_hostfile(user_hostfiles[0], ip,
2005-06-05 15:46:09 +00:00
host_key, options.hash_known_hosts);
} else {
/* Add unhashed "host,ip" */
2011-09-28 08:14:41 +00:00
r = add_host_to_hostfile(user_hostfiles[0],
2005-06-05 15:46:09 +00:00
hostline, host_key,
options.hash_known_hosts);
}
} else {
2011-09-28 08:14:41 +00:00
r = add_host_to_hostfile(user_hostfiles[0], host,
host_key, options.hash_known_hosts);
2005-06-05 15:46:09 +00:00
hostp = host;
}
if (!r)
logit("Failed to add the host to the list of known "
2011-09-28 08:14:41 +00:00
"hosts (%.500s).", user_hostfiles[0]);
else
logit("Warning: Permanently added '%.200s' (%s) to the "
2002-03-18 10:09:43 +00:00
"list of known hosts.", hostp, type);
break;
2010-03-08 11:19:52 +00:00
case HOST_REVOKED:
error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
error("@ WARNING: REVOKED HOST KEY DETECTED! @");
error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
error("The %s host key for %s is marked as revoked.", type, host);
error("This could mean that a stolen key is being used to");
error("impersonate this host.");
/*
* 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) {
error("%s host key for %.200s was revoked and you have "
"requested strict checking.", type, host);
goto fail;
}
goto continue_unsafe;
case HOST_CHANGED:
2010-03-08 11:19:52 +00:00
if (want_cert) {
/*
* This is only a debug() since it is valid to have
* CAs with wildcard DNS matches that don't match
* all hosts that one might visit.
*/
debug("Host certificate authority does not "
2011-02-17 11:47:40 +00:00
"match %s in %s:%lu", CA_MARKER,
host_found->file, host_found->line);
2010-03-08 11:19:52 +00:00
goto fail;
}
2006-09-30 13:38:06 +00:00
if (readonly == ROQUIET)
goto fail;
if (options.check_host_ip && host_ip_differ) {
2004-10-28 16:11:31 +00:00
char *key_msg;
if (ip_status == HOST_NEW)
2004-10-28 16:11:31 +00:00
key_msg = "is unknown";
else if (ip_status == HOST_OK)
2004-10-28 16:11:31 +00:00
key_msg = "is unchanged";
else
2004-10-28 16:11:31 +00:00
key_msg = "has a different value";
error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
error("@ WARNING: POSSIBLE DNS SPOOFING DETECTED! @");
error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@");
error("The %s host key for %s has changed,", type, host);
2008-07-23 09:33:08 +00:00
error("and the key for the corresponding IP address %s", ip);
2004-10-28 16:11:31 +00:00
error("%s. This could either mean that", key_msg);
error("DNS SPOOFING is happening or the IP address for the host");
2001-05-04 04:14:23 +00:00
error("and its host key have changed at the same time.");
if (ip_status != HOST_NEW)
2011-02-17 11:47:40 +00:00
error("Offending key for IP in %s:%lu",
ip_found->file, ip_found->line);
}
/* The host key has changed. */
2004-02-26 10:52:33 +00:00
warn_changed_key(host_key);
error("Add correct host key in %.100s to get rid of this message.",
2011-09-28 08:14:41 +00:00
user_hostfiles[0]);
2011-02-17 11:47:40 +00:00
error("Offending %s key in %s:%lu", key_type(host_found->key),
host_found->file, host_found->line);
/*
* If strict host key checking is in use, the user will have
* to edit the key manually and we can only abort.
*/
2002-03-18 10:09:43 +00:00
if (options.strict_host_key_checking) {
error("%s host key for %.200s has changed and you have "
"requested strict checking.", type, host);
goto fail;
}
2010-03-08 11:19:52 +00:00
continue_unsafe:
/*
* If strict host key checking has not been requested, allow
* the connection but without MITM-able authentication or
2006-09-30 13:38:06 +00:00
* forwarding.
*/
if (options.password_authentication) {
2002-03-18 10:09:43 +00:00
error("Password authentication is disabled to avoid "
"man-in-the-middle attacks.");
options.password_authentication = 0;
2008-07-23 09:33:08 +00:00
cancelled_forwarding = 1;
}
if (options.kbd_interactive_authentication) {
error("Keyboard-interactive authentication is disabled"
" to avoid man-in-the-middle attacks.");
options.kbd_interactive_authentication = 0;
options.challenge_response_authentication = 0;
2008-07-23 09:33:08 +00:00
cancelled_forwarding = 1;
}
if (options.challenge_response_authentication) {
error("Challenge/response authentication is disabled"
" to avoid man-in-the-middle attacks.");
options.challenge_response_authentication = 0;
2008-07-23 09:33:08 +00:00
cancelled_forwarding = 1;
}
if (options.forward_agent) {
2002-03-18 10:09:43 +00:00
error("Agent forwarding is disabled to avoid "
"man-in-the-middle attacks.");
options.forward_agent = 0;
2008-07-23 09:33:08 +00:00
cancelled_forwarding = 1;
}
2001-05-04 04:14:23 +00:00
if (options.forward_x11) {
2002-03-18 10:09:43 +00:00
error("X11 forwarding is disabled to avoid "
"man-in-the-middle attacks.");
2001-05-04 04:14:23 +00:00
options.forward_x11 = 0;
2008-07-23 09:33:08 +00:00
cancelled_forwarding = 1;
2001-05-04 04:14:23 +00:00
}
2002-03-18 10:09:43 +00:00
if (options.num_local_forwards > 0 ||
options.num_remote_forwards > 0) {
error("Port forwarding is disabled to avoid "
"man-in-the-middle attacks.");
options.num_local_forwards =
options.num_remote_forwards = 0;
2008-07-23 09:33:08 +00:00
cancelled_forwarding = 1;
2001-05-04 04:14:23 +00:00
}
2006-09-30 13:38:06 +00:00
if (options.tun_open != SSH_TUNMODE_NO) {
error("Tunnel forwarding is disabled to avoid "
"man-in-the-middle attacks.");
options.tun_open = SSH_TUNMODE_NO;
2008-07-23 09:33:08 +00:00
cancelled_forwarding = 1;
2006-09-30 13:38:06 +00:00
}
2008-07-23 09:33:08 +00:00
if (options.exit_on_forward_failure && cancelled_forwarding)
fatal("Error: forwarding disabled due to host key "
"check failure");
/*
* 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
2010-03-08 11:19:52 +00:00
* by that sentence, and ask the user if he/she wishes to
* accept the authentication.
*/
break;
2002-10-29 10:16:02 +00:00
case HOST_FOUND:
fatal("internal error");
break;
}
2001-05-04 04:14:23 +00:00
if (options.check_host_ip && host_status != HOST_CHANGED &&
ip_status == HOST_CHANGED) {
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snprintf(msg, sizeof(msg),
"Warning: the %s host key for '%.200s' "
"differs from the key for the IP address '%.128s'"
2011-02-17 11:47:40 +00:00
"\nOffending key for IP in %s:%lu",
type, host, ip, ip_found->file, ip_found->line);
2002-03-18 10:09:43 +00:00
if (host_status == HOST_OK) {
len = strlen(msg);
snprintf(msg + len, sizeof(msg) - len,
2011-02-17 11:47:40 +00:00
"\nMatching host key in %s:%lu",
host_found->file, host_found->line);
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}
2001-05-04 04:14:23 +00:00
if (options.strict_host_key_checking == 1) {
logit("%s", msg);
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error("Exiting, you have requested strict checking.");
goto fail;
2001-05-04 04:14:23 +00:00
} else if (options.strict_host_key_checking == 2) {
2002-03-18 10:09:43 +00:00
strlcat(msg, "\nAre you sure you want "
"to continue connecting (yes/no)? ", sizeof(msg));
if (!confirm(msg))
goto fail;
} else {
logit("%s", msg);
2001-05-04 04:14:23 +00:00
}
}
2013-09-18 17:27:38 +00:00
free(ip);
free(host);
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if (host_hostkeys != NULL)
free_hostkeys(host_hostkeys);
if (ip_hostkeys != NULL)
free_hostkeys(ip_hostkeys);
2002-03-18 10:09:43 +00:00
return 0;
2000-02-24 14:29:47 +00:00
2002-03-18 10:09:43 +00:00
fail:
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if (want_cert && host_status != HOST_REVOKED) {
/*
* No matching certificate. Downgrade cert to raw key and
* search normally.
*/
debug("No matching CA found. Retry with plain key");
raw_key = key_from_private(host_key);
if (key_drop_cert(raw_key) != 0)
fatal("Couldn't drop certificate");
host_key = raw_key;
goto retry;
}
if (raw_key != NULL)
key_free(raw_key);
2013-09-18 17:27:38 +00:00
free(ip);
free(host);
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if (host_hostkeys != NULL)
free_hostkeys(host_hostkeys);
if (ip_hostkeys != NULL)
free_hostkeys(ip_hostkeys);
2002-03-18 10:09:43 +00:00
return -1;
}
/* returns 0 if key verifies or -1 if key does NOT verify */
2002-03-18 10:09:43 +00:00
int
verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
{
2004-02-26 10:52:33 +00:00
int flags = 0;
2011-02-17 11:47:40 +00:00
char *fp;
Key *plain = NULL;
2011-02-17 11:47:40 +00:00
fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
debug("Server host key: %s %s", key_type(host_key), fp);
2013-09-18 17:27:38 +00:00
free(fp);
2002-03-18 10:09:43 +00:00
if (options.verify_host_key_dns) {
/*
* XXX certs are not yet supported for DNS, so downgrade
* them and try the plain key.
*/
plain = key_from_private(host_key);
if (key_is_cert(plain))
key_drop_cert(plain);
if (verify_host_key_dns(host, hostaddr, plain, &flags) == 0) {
if (flags & DNS_VERIFY_FOUND) {
if (options.verify_host_key_dns == 1 &&
flags & DNS_VERIFY_MATCH &&
flags & DNS_VERIFY_SECURE) {
key_free(plain);
return 0;
}
if (flags & DNS_VERIFY_MATCH) {
matching_host_key_dns = 1;
} else {
warn_changed_key(plain);
error("Update the SSHFP RR in DNS "
"with the new host key to get rid "
"of this message.");
}
2004-02-26 10:52:33 +00:00
}
}
key_free(plain);
}
2011-09-28 08:14:41 +00:00
return check_host_key(host, hostaddr, options.port, host_key, RDRW,
options.user_hostfiles, options.num_user_hostfiles,
options.system_hostfiles, options.num_system_hostfiles);
}
2000-02-24 14:29:47 +00:00
/*
* 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(Sensitive *sensitive, const char *orighost,
2011-02-17 11:47:40 +00:00
struct sockaddr *hostaddr, u_short port, struct passwd *pw, int timeout_ms)
2000-02-24 14:29:47 +00:00
{
2014-01-30 10:56:49 +00:00
char *host;
char *server_user, *local_user;
local_user = xstrdup(pw->pw_name);
server_user = options.user ? options.user : local_user;
2000-02-24 14:29:47 +00:00
/* Convert the user-supplied hostname into all lowercase. */
host = xstrdup(orighost);
2014-01-30 10:56:49 +00:00
lowercase(host);
2000-02-24 14:29:47 +00:00
/* Exchange protocol version identification strings with the server. */
ssh_exchange_identification(timeout_ms);
2000-02-24 14:29:47 +00:00
/* Put the connection into non-blocking mode. */
packet_set_nonblocking();
/* key exchange */
/* authenticate user */
if (compat20) {
2011-02-17 11:47:40 +00:00
ssh_kex2(host, hostaddr, port);
ssh_userauth2(local_user, server_user, host, sensitive);
} else {
ssh_kex(host, hostaddr);
ssh_userauth1(local_user, server_user, host, sensitive);
}
2013-09-18 17:27:38 +00:00
free(local_user);
2000-02-24 14:29:47 +00:00
}
void
ssh_put_password(char *password)
{
int size;
char *padded;
2001-05-04 04:14:23 +00:00
if (datafellows & SSH_BUG_PASSWORDPAD) {
2002-03-18 10:09:43 +00:00
packet_put_cstring(password);
2001-05-04 04:14:23 +00:00
return;
}
size = roundup(strlen(password) + 1, 32);
2006-09-30 13:38:06 +00:00
padded = xcalloc(1, size);
strlcpy(padded, password, size);
packet_put_string(padded, size);
2014-03-22 15:23:38 +00:00
explicit_bzero(padded, size);
2013-09-18 17:27:38 +00:00
free(padded);
}
2002-10-29 10:16:02 +00:00
/* print all known host keys for a given host, but skip keys of given type */
static int
2011-02-17 11:47:40 +00:00
show_other_keys(struct hostkeys *hostkeys, Key *key)
2002-10-29 10:16:02 +00:00
{
2014-01-30 10:56:49 +00:00
int type[] = {
KEY_RSA1,
KEY_RSA,
KEY_DSA,
KEY_ECDSA,
KEY_ED25519,
-1
};
2011-02-17 11:47:40 +00:00
int i, ret = 0;
char *fp, *ra;
const struct hostkey_entry *found;
2002-10-29 10:16:02 +00:00
for (i = 0; type[i] != -1; i++) {
if (type[i] == key->type)
continue;
2011-02-17 11:47:40 +00:00
if (!lookup_key_in_hostkeys_by_type(hostkeys, type[i], &found))
2002-10-29 10:16:02 +00:00
continue;
2011-02-17 11:47:40 +00:00
fp = key_fingerprint(found->key, SSH_FP_MD5, SSH_FP_HEX);
ra = key_fingerprint(found->key, SSH_FP_MD5, SSH_FP_RANDOMART);
logit("WARNING: %s key found for host %s\n"
"in %s:%lu\n"
"%s key fingerprint %s.",
key_type(found->key),
found->host, found->file, found->line,
key_type(found->key), fp);
if (options.visual_host_key)
logit("%s", ra);
2013-09-18 17:27:38 +00:00
free(ra);
free(fp);
2011-02-17 11:47:40 +00:00
ret = 1;
2002-10-29 10:16:02 +00:00
}
2011-02-17 11:47:40 +00:00
return ret;
2002-10-29 10:16:02 +00:00
}
2004-02-26 10:52:33 +00:00
static void
warn_changed_key(Key *host_key)
{
char *fp;
fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
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)!");
2011-02-17 11:47:40 +00:00
error("It is also possible that a host key has just been changed.");
2004-02-26 10:52:33 +00:00
error("The fingerprint for the %s key sent by the remote host is\n%s.",
2011-02-17 11:47:40 +00:00
key_type(host_key), fp);
2004-02-26 10:52:33 +00:00
error("Please contact your system administrator.");
2013-09-18 17:27:38 +00:00
free(fp);
2004-02-26 10:52:33 +00:00
}
2006-03-22 20:41:37 +00:00
/*
* Execute a local command
*/
int
ssh_local_cmd(const char *args)
{
char *shell;
pid_t pid;
int status;
2011-02-17 11:47:40 +00:00
void (*osighand)(int);
2006-03-22 20:41:37 +00:00
if (!options.permit_local_command ||
args == NULL || !*args)
return (1);
2011-02-17 11:47:40 +00:00
if ((shell = getenv("SHELL")) == NULL || *shell == '\0')
2006-03-22 20:41:37 +00:00
shell = _PATH_BSHELL;
2011-02-17 11:47:40 +00:00
osighand = signal(SIGCHLD, SIG_DFL);
2006-03-22 20:41:37 +00:00
pid = fork();
if (pid == 0) {
2011-02-17 11:47:40 +00:00
signal(SIGPIPE, SIG_DFL);
2006-03-22 20:41:37 +00:00
debug3("Executing %s -c \"%s\"", shell, args);
execl(shell, shell, "-c", args, (char *)NULL);
error("Couldn't execute %s -c \"%s\": %s",
shell, args, strerror(errno));
_exit(1);
} else if (pid == -1)
fatal("fork failed: %.100s", strerror(errno));
while (waitpid(pid, &status, 0) == -1)
if (errno != EINTR)
fatal("Couldn't wait for child: %s", strerror(errno));
2011-02-17 11:47:40 +00:00
signal(SIGCHLD, osighand);
2006-03-22 20:41:37 +00:00
if (!WIFEXITED(status))
return (1);
return (WEXITSTATUS(status));
}