* 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 1.77 2000/08/28 03:50:54 deraadt Exp $");
+RCSID("$OpenBSD: sshconnect.c,v 1.105 2001/04/30 11:18:52 markus 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"
char *client_version_string = NULL;
char *server_version_string = NULL;
extern Options options;
-#ifdef HAVE___PROGNAME
extern char *__progname;
-#else /* HAVE___PROGNAME */
-static const char *__progname = "ssh";
-#endif /* HAVE___PROGNAME */
+
+/* AF_UNSPEC or AF_INET or AF_INET6 */
+extern int IPv4or6;
/*
* 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,
+ssh_proxy_connect(const char *host, u_short port, struct passwd *pw,
const char *proxy_command)
{
Buffer command;
char *argv[10];
/* Child. Permanently give up superuser privileges. */
- permanently_set_uid(original_real_uid);
+ permanently_set_uid(pw);
/* Redirect stdin and stdout. */
close(pin[1]);
/* Execute the proxy command. Note that we gave up any
extra privileges above. */
- execv(_PATH_BSHELL, argv);
- perror(_PATH_BSHELL);
+ execv(argv[0], argv);
+ perror(argv[0]);
exit(1);
}
/* Parent. */
* Creates a (possibly privileged) socket for use as the ssh connection.
*/
int
-ssh_create_socket(uid_t original_real_uid, int privileged, int family)
+ssh_create_socket(struct passwd *pw, int privileged, int family)
{
- int sock;
+ int sock, gaierr;
+ struct addrinfo hints, *res;
/*
* If we are running as root and want to connect to a privileged
error("rresvport: af=%d %.100s", 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;
+ }
+ /*
+ * Just create an ordinary socket on arbitrary port. We use
+ * the user's uid to create the socket.
+ */
+ temporarily_use_uid(pw);
+ sock = socket(family, SOCK_STREAM, 0);
+ if (sock < 0)
+ error("socket: %.100s", strerror(errno));
+ restore_uid();
+
+ /* Bind the socket to an alternative local IP address */
+ if (options.bind_address == NULL)
+ return sock;
+
+ memset(&hints, 0, sizeof(hints));
+ hints.ai_family = IPv4or6;
+ hints.ai_socktype = SOCK_STREAM;
+ 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;
}
int
ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
u_short port, int connection_attempts,
- int anonymous, uid_t original_real_uid,
+ int anonymous, struct passwd *pw,
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 addrinfo hints, *ai, *aitop;
struct linger linger;
+ struct servent *sp;
debug("ssh_connect: getuid %u geteuid %u anon %d",
(u_int) getuid(), (u_int) geteuid(), anonymous);
}
/* 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, pw, proxy_command);
/* No proxy command. */
host, ntop, strport);
/* Create a socket for connecting. */
- sock = ssh_create_socket(original_real_uid,
- !anonymous && geteuid() == 0 && port < IPPORT_RESERVED,
+ sock = ssh_create_socket(pw,
+#ifdef HAVE_CYGWIN
+ !anonymous,
+#else
+ !anonymous && geteuid() == 0,
+#endif
ai->ai_family);
if (sock < 0)
continue;
* hope that it will help with tcp_wrappers showing
* the remote uid as root.
*/
- temporarily_use_uid(original_real_uid);
+ temporarily_use_uid(pw);
if (connect(sock, ai->ai_addr, ai->ai_addrlen) >= 0) {
/* Successful connection. */
memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
/* 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));
+ 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);
* identification string.
*/
void
-ssh_exchange_identification()
+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 (;;) {
}
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");
options.forward_agent = 0;
/* 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))
fatal("write: %.100s", strerror(errno));
debug("Local version string %.100s", client_version_string);
}
+/* defaults to 'no' */
int
read_yes_or_no(const char *prompt, int defval)
{
FILE *f;
int retval = -1;
- if (isatty(0))
+ if (options.batch_mode)
+ return 0;
+
+ if (isatty(STDIN_FILENO))
f = stdin;
else
- f = fopen("/dev/tty", "rw");
+ f = fopen(_PATH_TTY, "rw");
if (f == NULL)
return 0;
retval = defval;
if (strcmp(buf, "yes") == 0)
retval = 1;
- if (strcmp(buf, "no") == 0)
+ else if (strcmp(buf, "no") == 0)
retval = 0;
+ else
+ fprintf(stderr, "Please type 'yes' or 'no'.\n");
if (retval != -1) {
if (f != stdin)
Key *file_key;
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];
+ int host_line, ip_line;
+ const char *host_file = NULL, *ip_file = NULL;
/*
* Force accepting of the host key for loopback/localhost. The
salen = sizeof(struct sockaddr_storage);
break;
}
- if (local) {
- debug("Forcing accepting of host key for loopback/localhost.");
+ if (local && options.host_key_alias == NULL) {
+ 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
+ * 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 (!add_host_to_hostfile(user_hostfile, ip, host_key))
+ log("Failed to add the %s host key for IP address '%.128s' to the list of known hosts (%.30s).",
+ type, ip, user_hostfile);
+ else
+ log("Warning: Permanently added the %s host key for IP address '%.128s' to the list of known hosts.",
+ type, ip);
}
break;
case HOST_NEW:
} else if (options.strict_host_key_checking == 2) {
/* The default */
char prompt[1024];
- char *fp = key_fingerprint(host_key);
+ fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
snprintf(prompt, sizeof(prompt),
- "The authenticity of host '%.200s' can't be established.\n"
+ "The authenticity of host '%.200s (%s)' can't be established.\n"
"%s key fingerprint is %s.\n"
"Are you sure you want to continue connecting (yes/no)? ",
- host, type, fp);
+ host, ip, type, fp);
+ xfree(fp);
if (!read_yes_or_no(prompt, -1))
- fatal("Aborted by user!\n");
+ fatal("Aborted by user!");
}
- 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
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. */
+ 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.");
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);
+ xfree(fp);
/*
* If strict host key checking is in use, the user will have
error("Agent forwarding is disabled to avoid trojan horses.");
options.forward_agent = 0;
}
+ if (options.forward_x11) {
+ error("X11 forwarding is disabled to avoid trojan horses.");
+ options.forward_x11 = 0;
+ }
+ if (options.num_local_forwards > 0 || options.num_remote_forwards > 0) {
+ error("Port forwarding is disabled to avoid trojan horses.");
+ 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
*/
break;
}
- if (options.check_host_ip)
- xfree(ip);
+
+ if (options.check_host_ip && host_status != HOST_CHANGED &&
+ ip_status == HOST_CHANGED) {
+ log("Warning: the %s host key for '%.200s' "
+ "differs from the key for the IP address '%.128s'",
+ type, host, ip);
+ if (host_status == HOST_OK)
+ log("Matching host key in %s:%d", host_file, host_line);
+ log("Offending key for IP in %s:%d", ip_file, ip_line);
+ if (options.strict_host_key_checking == 1) {
+ fatal("Exiting, you have requested strict checking.");
+ } else if (options.strict_host_key_checking == 2) {
+ if (!read_yes_or_no("Are you sure you want " \
+ "to continue connecting (yes/no)? ", -1))
+ fatal("Aborted by user!");
+ }
+ }
+
+ xfree(ip);
}
/*
* 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(Key **keys, int nkeys, 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 %u 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, keys, nkeys);
} 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, keys, nkeys);
+ }
+}
+
+void
+ssh_put_password(char *password)
+{
+ int size;
+ char *padded;
+
+ if (datafellows & SSH_BUG_PASSWORDPAD) {
+ packet_put_string(password, strlen(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);
}
andersk / openssh.git / blobdiff