* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
- * Created: Sat Mar 18 22:15:47 1995 ylo
* 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".
*/
#include "includes.h"
-RCSID("$OpenBSD: sshconnect.c,v 1.76 2000/06/17 20:30:10 markus Exp $");
+RCSID("$OpenBSD: sshconnect.c,v 1.154 2003/11/21 11:57:03 djm Exp $");
#include <openssl/bn.h>
-#include <openssl/dsa.h>
-#include <openssl/rsa.h>
+#include "ssh.h"
#include "xmalloc.h"
#include "rsa.h"
-#include "ssh.h"
#include "buffer.h"
#include "packet.h"
#include "uidswap.h"
#include "compat.h"
-#include "readconf.h"
#include "key.h"
#include "sshconnect.h"
#include "hostfile.h"
+#include "log.h"
+#include "readconf.h"
+#include "atomicio.h"
+#include "misc.h"
+#include "readpass.h"
+
+#include "dns.h"
char *client_version_string = NULL;
char *server_version_string = NULL;
+int matching_host_key_dns = 0;
+
+/* import */
extern Options options;
-#ifdef HAVE___PROGNAME
extern char *__progname;
-#else /* HAVE___PROGNAME */
-static const char *__progname = "ssh";
-#endif /* HAVE___PROGNAME */
+extern uid_t original_real_uid;
+extern uid_t original_effective_uid;
+extern pid_t proxy_command_pid;
+
+#ifndef INET6_ADDRSTRLEN /* for non IPv6 machines */
+#define INET6_ADDRSTRLEN 46
+#endif
+
+static int show_other_keys(const char *, Key *);
+static void warn_changed_key(Key *);
/*
* Connect to the given ssh server using a proxy command.
*/
-int
-ssh_proxy_connect(const char *host, u_short port, uid_t original_real_uid,
- const char *proxy_command)
+static int
+ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
{
Buffer command;
const char *cp;
/* Convert the port number into a string. */
snprintf(strport, sizeof strport, "%hu", port);
- /* Build the final command string in the buffer by making the
- appropriate substitutions to the given proxy command. */
+ /*
+ * Build the final command string in the buffer by making the
+ * appropriate substitutions to the given proxy command.
+ *
+ * Use "exec" to avoid "sh -c" processes on some platforms
+ * (e.g. Solaris)
+ */
buffer_init(&command);
+ buffer_append(&command, "exec ", 5);
+
for (cp = proxy_command; *cp; cp++) {
if (cp[0] == '%' && cp[1] == '%') {
buffer_append(&command, "%", 1);
/* 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",
- strerror(errno));
+ strerror(errno));
debug("Executing proxy command: %.500s", command_string);
char *argv[10];
/* Child. Permanently give up superuser privileges. */
- permanently_set_uid(original_real_uid);
+ seteuid(original_real_uid);
+ setuid(original_real_uid);
/* Redirect stdin and stdout. */
close(pin[1]);
/* Stderr is left as it is so that error messages get
printed on the user's terminal. */
- argv[0] = "/bin/sh";
+ argv[0] = _PATH_BSHELL;
argv[1] = "-c";
argv[2] = command_string;
argv[3] = NULL;
/* Execute the proxy command. Note that we gave up any
extra privileges above. */
- execv("/bin/sh", argv);
- perror("/bin/sh");
+ execv(argv[0], argv);
+ perror(argv[0]);
exit(1);
}
/* Parent. */
if (pid < 0)
fatal("fork failed: %.100s", strerror(errno));
+ else
+ proxy_command_pid = pid; /* save pid to clean up later */
/* Close child side of the descriptors. */
close(pin[0]);
/* Set the connection file descriptors. */
packet_set_connection(pout[0], pin[1]);
- return 1;
+ /* Indicate OK return */
+ return 0;
}
/*
* Creates a (possibly privileged) socket for use as the ssh connection.
*/
-int
-ssh_create_socket(uid_t original_real_uid, int privileged, int family)
+static int
+ssh_create_socket(int privileged, struct addrinfo *ai)
{
- int sock;
+ int sock, gaierr;
+ struct addrinfo hints, *res;
/*
* If we are running as root and want to connect to a privileged
*/
if (privileged) {
int p = IPPORT_RESERVED - 1;
- sock = rresvport_af(&p, family);
+ PRIV_START;
+ sock = rresvport_af(&p, ai->ai_family);
+ PRIV_END;
if (sock < 0)
- error("rresvport: af=%d %.100s", family, strerror(errno));
+ error("rresvport: af=%d %.100s", ai->ai_family,
+ strerror(errno));
else
debug("Allocated local port %d.", p);
- } else {
- /*
- * Just create an ordinary socket on arbitrary port. We use
- * the user's uid to create the socket.
- */
- temporarily_use_uid(original_real_uid);
- sock = socket(family, SOCK_STREAM, 0);
- if (sock < 0)
- error("socket: %.100s", strerror(errno));
- restore_uid();
+ return sock;
}
+ sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
+ if (sock < 0)
+ error("socket: %.100s", strerror(errno));
+
+ /* Bind the socket to an alternative local IP address */
+ if (options.bind_address == NULL)
+ return sock;
+
+ 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, "0", &hints, &res);
+ if (gaierr) {
+ error("getaddrinfo: %s: %s", options.bind_address,
+ gai_strerror(gaierr));
+ close(sock);
+ return -1;
+ }
+ if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) {
+ error("bind: %s: %s", options.bind_address, strerror(errno));
+ close(sock);
+ freeaddrinfo(res);
+ return -1;
+ }
+ freeaddrinfo(res);
return sock;
}
+static int
+timeout_connect(int sockfd, const struct sockaddr *serv_addr,
+ socklen_t addrlen, int timeout)
+{
+ fd_set *fdset;
+ struct timeval tv;
+ socklen_t optlen;
+ int fdsetsz, optval, rc, result = -1;
+
+ if (timeout <= 0)
+ return (connect(sockfd, serv_addr, addrlen));
+
+ if (fcntl(sockfd, F_SETFL, O_NONBLOCK) < 0)
+ return (-1);
+
+ rc = connect(sockfd, serv_addr, addrlen);
+ if (rc == 0)
+ return (0);
+ if (errno != EINPROGRESS)
+ return (-1);
+
+ fdsetsz = howmany(sockfd + 1, NFDBITS) * sizeof(fd_mask);
+ fdset = (fd_set *)xmalloc(fdsetsz);
+
+ memset(fdset, 0, fdsetsz);
+ FD_SET(sockfd, fdset);
+ tv.tv_sec = timeout;
+ tv.tv_usec = 0;
+
+ for(;;) {
+ rc = select(sockfd + 1, NULL, fdset, NULL, &tv);
+ if (rc != -1 || errno != EINTR)
+ break;
+ }
+
+ switch(rc) {
+ case 0:
+ /* Timed out */
+ errno = ETIMEDOUT;
+ break;
+ case -1:
+ /* Select error */
+ debug("select: %s", strerror(errno));
+ break;
+ case 1:
+ /* Completed or failed */
+ optval = 0;
+ optlen = sizeof(optval);
+ if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval,
+ &optlen) == -1) {
+ debug("getsockopt: %s", strerror(errno));
+ break;
+ }
+ if (optval != 0) {
+ errno = optval;
+ break;
+ }
+ result = 0;
+ break;
+ default:
+ /* Should not occur */
+ fatal("Bogus return (%d) from select()", rc);
+ }
+
+ xfree(fdset);
+ return (result);
+}
+
/*
* 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 anonymous is zero,
+ * If port is 0, the default port will be used. If needpriv is true,
* a privileged port will be allocated to make the connection.
- * This requires super-user privileges if anonymous is false.
+ * This requires super-user privileges if needpriv is true.
* 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.
+ * Return values:
+ * 0 for OK
+ * ECONNREFUSED if we got a "Connection Refused" by the peer on any address
+ * ECONNABORTED if we failed without a "Connection refused"
+ * Suitable error messages for the connection failure will already have been
+ * printed.
*/
int
ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
- u_short port, int connection_attempts,
- int anonymous, uid_t original_real_uid,
- const char *proxy_command)
+ u_short port, int family, int connection_attempts,
+ int needpriv, const char *proxy_command)
{
+ int gaierr;
+ int on = 1;
int sock = -1, attempt;
- struct servent *sp;
- struct addrinfo hints, *ai, *aitop;
char ntop[NI_MAXHOST], strport[NI_MAXSERV];
- int gaierr;
- struct linger linger;
+ struct addrinfo hints, *ai, *aitop;
+ struct servent *sp;
+ /*
+ * Did we get only other errors than "Connection refused" (which
+ * should block fallback to rsh and similar), or did we get at least
+ * one "Connection refused"?
+ */
+ int full_failure = 1;
- debug("ssh_connect: getuid %d geteuid %d anon %d",
- (int) getuid(), (int) geteuid(), anonymous);
+ debug2("ssh_connect: needpriv %d", needpriv);
/* Get default port if port has not been set. */
if (port == 0) {
}
/* If a proxy command is given, connect using it. */
if (proxy_command != NULL)
- return ssh_proxy_connect(host, port, original_real_uid, proxy_command);
+ return ssh_proxy_connect(host, port, proxy_command);
/* No proxy command. */
memset(&hints, 0, sizeof(hints));
- hints.ai_family = IPv4or6;
+ hints.ai_family = family;
hints.ai_socktype = SOCK_STREAM;
- snprintf(strport, sizeof strport, "%d", port);
+ snprintf(strport, sizeof strport, "%u", port);
if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0)
fatal("%s: %.100s: %s", __progname, host,
gai_strerror(gaierr));
* Try to connect several times. On some machines, the first time
* will sometimes fail. In general socket code appears to behave
* quite magically on many machines.
- */
- for (attempt = 0; attempt < connection_attempts; attempt++) {
+ */
+ for (attempt = 0; ;) {
if (attempt > 0)
debug("Trying again...");
host, ntop, strport);
/* Create a socket for connecting. */
- sock = ssh_create_socket(original_real_uid,
- !anonymous && geteuid() == 0 && port < IPPORT_RESERVED,
- ai->ai_family);
+ sock = ssh_create_socket(needpriv, ai);
if (sock < 0)
+ /* Any error is already output */
continue;
- /* Connect to the host. We use the user's uid in the
- * hope that it will help with tcp_wrappers showing
- * the remote uid as root.
- */
- temporarily_use_uid(original_real_uid);
- if (connect(sock, ai->ai_addr, ai->ai_addrlen) >= 0) {
+ if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen,
+ options.connection_timeout) >= 0) {
/* Successful connection. */
memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
- restore_uid();
break;
} else {
- debug("connect: %.100s", strerror(errno));
- restore_uid();
+ if (errno == ECONNREFUSED)
+ full_failure = 0;
+ debug("connect to address %s port %s: %s",
+ ntop, strport, strerror(errno));
/*
* Close the failed socket; there appear to
* be some problems when reusing a socket for
* which connect() has already returned an
* error.
*/
- shutdown(sock, SHUT_RDWR);
close(sock);
}
}
if (ai)
break; /* Successful connection. */
+ attempt++;
+ if (attempt >= connection_attempts)
+ break;
/* Sleep a moment before retrying. */
sleep(1);
}
freeaddrinfo(aitop);
/* Return failure if we didn't get a successful connection. */
- if (attempt >= connection_attempts)
- return 0;
+ if (attempt >= connection_attempts) {
+ logit("ssh: connect to host %s port %s: %s",
+ host, strport, strerror(errno));
+ return full_failure ? ECONNABORTED : ECONNREFUSED;
+ }
debug("Connection established.");
- /*
- * Set socket options. We would like the socket to disappear as soon
- * as it has been closed for whatever reason.
- */
- /* setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */
- linger.l_onoff = 1;
- linger.l_linger = 5;
- setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *) &linger, sizeof(linger));
+ /* Set keepalives if requested. */
+ if (options.keepalives &&
+ setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
+ sizeof(on)) < 0)
+ error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
/* Set the connection. */
packet_set_connection(sock, sock);
- return 1;
+ return 0;
}
/*
* Waits for the server identification string, and sends our own
* identification string.
*/
-void
-ssh_exchange_identification()
+static void
+ssh_exchange_identification(void)
{
char buf[256], remote_version[256]; /* must be same size! */
int remote_major, remote_minor, i, mismatch;
int connection_in = packet_get_connection_in();
int connection_out = packet_get_connection_out();
+ int minor1 = PROTOCOL_MINOR_1;
/* Read other side\'s version identification. */
for (;;) {
&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);
+ remote_major, remote_minor, remote_version);
compat_datafellows(remote_version);
mismatch = 0;
- switch(remote_major) {
+ switch (remote_major) {
case 1:
if (remote_minor == 99 &&
(options.protocol & SSH_PROTO_2) &&
}
if (remote_minor < 3) {
fatal("Remote machine has too old SSH software version.");
- } else if (remote_minor == 3) {
+ } else if (remote_minor == 3 || remote_minor == 4) {
/* We speak 1.3, too. */
enable_compat13();
+ minor1 = 3;
if (options.forward_agent) {
- log("Agent forwarding disabled for protocol 1.3");
+ logit("Agent forwarding disabled for protocol 1.3");
options.forward_agent = 0;
}
}
fatal("Protocol major versions differ: %d vs. %d",
(options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
remote_major);
- if (compat20)
- packet_set_ssh2_format();
/* Send our own protocol version identification. */
snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n",
compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1,
- compat20 ? PROTOCOL_MINOR_2 : PROTOCOL_MINOR_1,
+ compat20 ? PROTOCOL_MINOR_2 : minor1,
SSH_VERSION);
- if (atomicio(write, connection_out, buf, strlen(buf)) != strlen(buf))
+ if (atomicio(vwrite, connection_out, buf, strlen(buf)) != strlen(buf))
fatal("write: %.100s", strerror(errno));
client_version_string = xstrdup(buf);
chop(client_version_string);
debug("Local version string %.100s", client_version_string);
}
-int
-read_yes_or_no(const char *prompt, int defval)
+/* defaults to 'no' */
+static int
+confirm(const char *prompt)
{
- char buf[1024];
- FILE *f;
- int retval = -1;
-
- if (isatty(0))
- f = stdin;
- else
- f = fopen("/dev/tty", "rw");
+ const char *msg, *again = "Please type 'yes' or 'no': ";
+ char *p;
+ int ret = -1;
- if (f == NULL)
+ if (options.batch_mode)
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;
- }
+ 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;
+ if (p && strncasecmp(p, "yes", 3) == 0)
+ ret = 1;
+ if (p)
+ xfree(p);
+ if (ret != -1)
+ return ret;
}
}
/*
- * check whether the supplied host key is valid, return only if ok.
+ * check whether the supplied host key is valid, return -1 if the key
+ * is not valid. the user_hostfile will not be updated if 'readonly' is true.
*/
-
-void
+static int
check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
- const char *user_hostfile, const char *system_hostfile)
+ int readonly, const char *user_hostfile, const char *system_hostfile)
{
Key *file_key;
- char *type = key_type(host_key);
+ const char *type = key_type(host_key);
char *ip = NULL;
- char hostline[1000], *hostp;
+ char hostline[1000], *hostp, *fp;
HostStatus host_status;
HostStatus ip_status;
int local = 0, host_ip_differ = 0;
int salen;
char ntop[NI_MAXHOST];
+ char msg[1024];
+ int len, host_line, ip_line;
+ const char *host_file = NULL, *ip_file = NULL;
/*
* Force accepting of the host key for loopback/localhost. The
/** hostaddr == 0! */
switch (hostaddr->sa_family) {
case AF_INET:
- local = (ntohl(((struct sockaddr_in *)hostaddr)->sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
+ local = (ntohl(((struct sockaddr_in *)hostaddr)->
+ sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
salen = sizeof(struct sockaddr_in);
break;
case AF_INET6:
- local = IN6_IS_ADDR_LOOPBACK(&(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
+ local = IN6_IS_ADDR_LOOPBACK(
+ &(((struct sockaddr_in6 *)hostaddr)->sin6_addr));
salen = sizeof(struct sockaddr_in6);
break;
default:
salen = sizeof(struct sockaddr_storage);
break;
}
- if (local) {
- debug("Forcing accepting of host key for loopback/localhost.");
- return;
+ if (options.no_host_authentication_for_localhost == 1 && local &&
+ options.host_key_alias == NULL) {
+ debug("Forcing accepting of host key for "
+ "loopback/localhost.");
+ return 0;
}
/*
- * Turn off check_host_ip for proxy connects, since
- * we don't have the remote ip-address
+ * We don't have the remote ip-address for connections
+ * using a proxy command
*/
- if (options.proxy_command != NULL && options.check_host_ip)
- options.check_host_ip = 0;
-
- if (options.check_host_ip) {
+ if (options.proxy_command == NULL) {
if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop),
NULL, 0, NI_NUMERICHOST) != 0)
fatal("check_host_key: getnameinfo failed");
ip = xstrdup(ntop);
+ } else {
+ ip = xstrdup("<no hostip for proxy command>");
+ }
+ /*
+ * 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
+ */
+ if (options.check_host_ip &&
+ (local || strcmp(host, ip) == 0 || options.proxy_command != NULL))
+ options.check_host_ip = 0;
+
+ /*
+ * Allow the user to record the key under a different name. This is
+ * useful for ssh tunneling over forwarded connections or if you run
+ * multiple sshd's on different ports on the same machine.
+ */
+ if (options.host_key_alias != NULL) {
+ host = options.host_key_alias;
+ debug("using hostkeyalias: %s", host);
}
/*
* 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(user_hostfile, host, host_key, file_key);
- if (host_status == HOST_NEW)
- host_status = check_host_in_hostfile(system_hostfile, host, host_key, file_key);
+ host_file = user_hostfile;
+ host_status = check_host_in_hostfile(host_file, host, host_key,
+ file_key, &host_line);
+ if (host_status == HOST_NEW) {
+ host_file = system_hostfile;
+ host_status = check_host_in_hostfile(host_file, host, host_key,
+ file_key, &host_line);
+ }
/*
* 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)) {
+ if (options.check_host_ip) {
Key *ip_key = key_new(host_key->type);
- ip_status = check_host_in_hostfile(user_hostfile, ip, host_key, ip_key);
- if (ip_status == HOST_NEW)
- ip_status = check_host_in_hostfile(system_hostfile, ip, host_key, ip_key);
+ ip_file = user_hostfile;
+ ip_status = check_host_in_hostfile(ip_file, ip, host_key,
+ ip_key, &ip_line);
+ if (ip_status == HOST_NEW) {
+ ip_file = system_hostfile;
+ ip_status = check_host_in_hostfile(ip_file, ip,
+ host_key, ip_key, &ip_line);
+ }
if (host_status == HOST_CHANGED &&
(ip_status != HOST_CHANGED || !key_equal(ip_key, file_key)))
host_ip_differ = 1;
/* The host is known and the key matches. */
debug("Host '%.200s' is known and matches the %s host key.",
host, type);
- if (options.check_host_ip) {
- if (ip_status == HOST_NEW) {
- if (!add_host_to_hostfile(user_hostfile, ip, host_key))
- log("Failed to add the %s host key for IP address '%.30s' to the list of known hosts (%.30s).",
- type, ip, user_hostfile);
- else
- log("Warning: Permanently added the %s host key for IP address '%.30s' to the list of known hosts.",
- type, ip);
- } else if (ip_status != HOST_OK)
- log("Warning: the %s host key for '%.200s' differs from the key for the IP address '%.30s'",
- type, host, ip);
+ debug("Found key in %s:%d", host_file, host_line);
+ if (options.check_host_ip && ip_status == HOST_NEW) {
+ if (readonly)
+ logit("%s host key for IP address "
+ "'%.128s' not in list of known hosts.",
+ type, ip);
+ else if (!add_host_to_hostfile(user_hostfile, ip,
+ host_key))
+ logit("Failed to add the %s host key for IP "
+ "address '%.128s' to the list of known "
+ "hosts (%.30s).", type, ip, user_hostfile);
+ else
+ logit("Warning: Permanently added the %s host "
+ "key for IP address '%.128s' to the list "
+ "of known hosts.", type, ip);
}
break;
case HOST_NEW:
+ if (readonly)
+ goto fail;
/* 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 %s host key is known for %.200s and you have requested strict checking.", type, host);
+ /*
+ * 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];
+
+ if (show_other_keys(host, host_key))
+ snprintf(msg1, sizeof(msg1),
+ "\nbut keys of different type are already"
+ " known for this host.");
+ else
+ snprintf(msg1, sizeof(msg1), ".");
/* The default */
- char prompt[1024];
- char *fp = key_fingerprint(host_key);
- snprintf(prompt, sizeof(prompt),
- "The authenticity of host '%.200s' can't be established.\n"
- "%s key fingerprint is %s.\n"
- "Are you sure you want to continue connecting (yes/no)? ",
- host, type, fp);
- if (!read_yes_or_no(prompt, -1))
- fatal("Aborted by user!\n");
+ fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
+ msg2[0] = '\0';
+ if (options.verify_host_key_dns) {
+ 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");
+ }
+ snprintf(msg, sizeof(msg),
+ "The authenticity of host '%.200s (%s)' can't be "
+ "established%s\n"
+ "%s key fingerprint is %s.\n%s"
+ "Are you sure you want to continue connecting "
+ "(yes/no)? ",
+ host, ip, msg1, type, fp, msg2);
+ xfree(fp);
+ if (!confirm(msg))
+ goto fail;
}
- if (options.check_host_ip && ip_status == HOST_NEW && strcmp(host, ip)) {
+ if (options.check_host_ip && ip_status == HOST_NEW) {
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 not in strict mode, add the key automatically to the
+ * local known_hosts file.
+ */
if (!add_host_to_hostfile(user_hostfile, hostp, host_key))
- log("Failed to add the host to the list of known hosts (%.500s).",
- user_hostfile);
+ logit("Failed to add the host to the list of known "
+ "hosts (%.500s).", user_hostfile);
else
- log("Warning: Permanently added '%.200s' (%s) to the list of known hosts.",
- hostp, type);
+ logit("Warning: Permanently added '%.200s' (%s) to the "
+ "list of known hosts.", hostp, type);
break;
case HOST_CHANGED:
if (options.check_host_ip && host_ip_differ) {
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");
+ error("and its host key have changed at the same time.");
+ if (ip_status != HOST_NEW)
+ error("Offending key for IP in %s:%d", ip_file, ip_line);
}
/* 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 %s host key has just been changed.", type);
- error("Please contact your system administrator.");
+ warn_changed_key(host_key);
error("Add correct host key in %.100s to get rid of this message.",
- user_hostfile);
+ user_hostfile);
+ error("Offending key in %s:%d", host_file, host_line);
/*
* 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("%s host key for %.200s has changed and you have requested strict checking.", type, host);
+ if (options.strict_host_key_checking) {
+ error("%s host key for %.200s has changed and you have "
+ "requested strict checking.", type, host);
+ goto fail;
+ }
/*
* If strict host key checking has not been requested, allow
- * the connection but without password authentication or
+ * the connection but without MITM-able authentication or
* agent forwarding.
*/
if (options.password_authentication) {
- error("Password authentication is disabled to avoid trojan horses.");
+ error("Password authentication is disabled to avoid "
+ "man-in-the-middle attacks.");
options.password_authentication = 0;
}
+ 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;
+ }
+ if (options.challenge_response_authentication) {
+ error("Challenge/response authentication is disabled"
+ " to avoid man-in-the-middle attacks.");
+ options.challenge_response_authentication = 0;
+ }
if (options.forward_agent) {
- error("Agent forwarding is disabled to avoid trojan horses.");
+ error("Agent forwarding is disabled to avoid "
+ "man-in-the-middle attacks.");
options.forward_agent = 0;
}
+ if (options.forward_x11) {
+ error("X11 forwarding is disabled to avoid "
+ "man-in-the-middle attacks.");
+ options.forward_x11 = 0;
+ }
+ 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;
+ }
/*
* XXX Should permit the user to change to use the new id.
* This could be done by converting the host key to an
* accept the authentication.
*/
break;
+ case HOST_FOUND:
+ fatal("internal error");
+ break;
+ }
+
+ if (options.check_host_ip && host_status != HOST_CHANGED &&
+ ip_status == HOST_CHANGED) {
+ snprintf(msg, sizeof(msg),
+ "Warning: the %s host key for '%.200s' "
+ "differs from the key for the IP address '%.128s'"
+ "\nOffending key for IP in %s:%d",
+ type, host, ip, ip_file, ip_line);
+ if (host_status == HOST_OK) {
+ len = strlen(msg);
+ snprintf(msg + len, sizeof(msg) - len,
+ "\nMatching host key in %s:%d",
+ host_file, host_line);
+ }
+ if (options.strict_host_key_checking == 1) {
+ logit("%s", msg);
+ error("Exiting, you have requested strict checking.");
+ goto fail;
+ } else if (options.strict_host_key_checking == 2) {
+ strlcat(msg, "\nAre you sure you want "
+ "to continue connecting (yes/no)? ", sizeof(msg));
+ if (!confirm(msg))
+ goto fail;
+ } else {
+ logit("%s", msg);
+ }
+ }
+
+ xfree(ip);
+ return 0;
+
+fail:
+ xfree(ip);
+ return -1;
+}
+
+/* returns 0 if key verifies or -1 if key does NOT verify */
+int
+verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
+{
+ struct stat st;
+ int flags = 0;
+
+ if (options.verify_host_key_dns &&
+ verify_host_key_dns(host, hostaddr, host_key, &flags) == 0) {
+
+ if (flags & DNS_VERIFY_FOUND) {
+
+ if (options.verify_host_key_dns == 1 &&
+ flags & DNS_VERIFY_MATCH &&
+ flags & DNS_VERIFY_SECURE)
+ return 0;
+
+ if (flags & DNS_VERIFY_MATCH) {
+ matching_host_key_dns = 1;
+ } else {
+ warn_changed_key(host_key);
+ error("Update the SSHFP RR in DNS with the new "
+ "host key to get rid of this message.");
+ }
+ }
}
- if (options.check_host_ip)
- xfree(ip);
+
+ /* return ok if the key can be found in an old keyfile */
+ if (stat(options.system_hostfile2, &st) == 0 ||
+ stat(options.user_hostfile2, &st) == 0) {
+ if (check_host_key(host, hostaddr, host_key, /*readonly*/ 1,
+ options.user_hostfile2, options.system_hostfile2) == 0)
+ return 0;
+ }
+ return check_host_key(host, hostaddr, host_key, /*readonly*/ 0,
+ options.user_hostfile, options.system_hostfile);
}
/*
* 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)
+ssh_login(Sensitive *sensitive, const char *orighost,
+ struct sockaddr *hostaddr, struct passwd *pw)
{
- struct passwd *pw;
char *host, *cp;
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;
/* authenticate user */
if (compat20) {
ssh_kex2(host, hostaddr);
- ssh_userauth2(server_user, host);
+ ssh_userauth2(local_user, server_user, host, sensitive);
} else {
ssh_kex(host, hostaddr);
- ssh_userauth(local_user, server_user, host, host_key_valid, own_host_key);
+ ssh_userauth1(local_user, server_user, host, sensitive);
}
}
+
+void
+ssh_put_password(char *password)
+{
+ int size;
+ char *padded;
+
+ if (datafellows & SSH_BUG_PASSWORDPAD) {
+ packet_put_cstring(password);
+ return;
+ }
+ size = roundup(strlen(password) + 1, 32);
+ padded = xmalloc(size);
+ memset(padded, 0, size);
+ strlcpy(padded, password, size);
+ packet_put_string(padded, size);
+ memset(padded, 0, size);
+ xfree(padded);
+}
+
+static int
+show_key_from_file(const char *file, const char *host, int keytype)
+{
+ Key *found;
+ char *fp;
+ int line, ret;
+
+ found = key_new(keytype);
+ if ((ret = lookup_key_in_hostfile_by_type(file, host,
+ keytype, found, &line))) {
+ fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX);
+ logit("WARNING: %s key found for host %s\n"
+ "in %s:%d\n"
+ "%s key fingerprint %s.",
+ key_type(found), host, file, line,
+ key_type(found), fp);
+ xfree(fp);
+ }
+ key_free(found);
+ return (ret);
+}
+
+/* print all known host keys for a given host, but skip keys of given type */
+static int
+show_other_keys(const char *host, Key *key)
+{
+ int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, -1};
+ int i, found = 0;
+
+ for (i = 0; type[i] != -1; i++) {
+ if (type[i] == key->type)
+ continue;
+ if (type[i] != KEY_RSA1 &&
+ show_key_from_file(options.user_hostfile2, host, type[i])) {
+ found = 1;
+ continue;
+ }
+ if (type[i] != KEY_RSA1 &&
+ show_key_from_file(options.system_hostfile2, host, type[i])) {
+ found = 1;
+ continue;
+ }
+ if (show_key_from_file(options.user_hostfile, host, type[i])) {
+ found = 1;
+ continue;
+ }
+ if (show_key_from_file(options.system_hostfile, host, type[i])) {
+ found = 1;
+ continue;
+ }
+ debug2("no key of type %d for host %s", type[i], host);
+ }
+ return (found);
+}
+
+static void
+warn_changed_key(Key *host_key)
+{
+ char *fp;
+ const char *type = key_type(host_key);
+
+ 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)!");
+ error("It is also possible that the %s host key has just been changed.", type);
+ error("The fingerprint for the %s key sent by the remote host is\n%s.",
+ type, fp);
+ error("Please contact your system administrator.");
+
+ xfree(fp);
+}
andersk / openssh.git / blobdiff