+/* $OpenBSD: sshconnect.c,v 1.202 2007/09/04 11:15:55 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
*/
#include "includes.h"
-RCSID("$OpenBSD: sshconnect.c,v 1.115 2001/10/08 19:05:05 markus Exp $");
-#include <openssl/bn.h>
+#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>
+
+#include <ctype.h>
+#include <errno.h>
+#include <netdb.h>
+#ifdef HAVE_PATHS_H
+#include <paths.h>
+#endif
+#include <pwd.h>
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
-#include "ssh.h"
#include "xmalloc.h"
+#include "key.h"
+#include "hostfile.h"
+#include "ssh.h"
#include "rsa.h"
#include "buffer.h"
#include "packet.h"
#include "readconf.h"
#include "atomicio.h"
#include "misc.h"
+#include "dns.h"
+#include "version.h"
char *client_version_string = NULL;
char *server_version_string = NULL;
+static int matching_host_key_dns = 0;
+
+/* import */
extern Options options;
extern char *__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 const char *
-sockaddr_ntop(struct sockaddr *sa)
+static int show_other_keys(const char *, Key *);
+static void warn_changed_key(Key *);
+
+static void
+ms_subtract_diff(struct timeval *start, int *ms)
{
- void *addr;
- static char addrbuf[INET6_ADDRSTRLEN];
+ struct timeval diff, finish;
- switch (sa->sa_family) {
- case AF_INET:
- addr = &((struct sockaddr_in *)sa)->sin_addr;
- break;
- case AF_INET6:
- addr = &((struct sockaddr_in6 *)sa)->sin6_addr;
- break;
- default:
- /* This case should be protected against elsewhere */
- abort();
- }
- inet_ntop(sa->sa_family, addr, addrbuf, sizeof(addrbuf));
- return addrbuf;
+ gettimeofday(&finish, NULL);
+ timersub(&finish, start, &diff);
+ *ms -= (diff.tv_sec * 1000) + (diff.tv_usec / 1000);
+}
+
+static void
+ms_to_timeval(struct timeval *tv, int ms)
+{
+ tv->tv_sec = ms / 1000;
+ tv->tv_usec = (ms % 1000) * 1000;
}
/*
* Connect to the given ssh server using a proxy command.
*/
static int
-ssh_proxy_connect(const char *host, u_short port, struct passwd *pw,
- const char *proxy_command)
+ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
{
- Buffer command;
- const char *cp;
- char *command_string;
+ char *command_string, *tmp;
int pin[2], pout[2];
pid_t pid;
- char strport[NI_MAXSERV];
+ char *shell, strport[NI_MAXSERV];
+
+ if ((shell = getenv("SHELL")) == NULL)
+ shell = _PATH_BSHELL;
/* 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. */
- buffer_init(&command);
- for (cp = proxy_command; *cp; cp++) {
- if (cp[0] == '%' && cp[1] == '%') {
- buffer_append(&command, "%", 1);
- cp++;
- continue;
- }
- if (cp[0] == '%' && cp[1] == 'h') {
- buffer_append(&command, host, strlen(host));
- cp++;
- continue;
- }
- if (cp[0] == '%' && cp[1] == 'p') {
- buffer_append(&command, strport, strlen(strport));
- cp++;
- continue;
- }
- buffer_append(&command, cp, 1);
- }
- buffer_append(&command, "\0", 1);
-
- /* Get the final command string. */
- command_string = buffer_ptr(&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)
+ */
+ xasprintf(&tmp, "exec %s", proxy_command);
+ command_string = percent_expand(tmp, "h", host,
+ "p", strport, (char *)NULL);
+ xfree(tmp);
/* 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(pw);
+ permanently_drop_suid(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] = _PATH_BSHELL;
+ argv[0] = shell;
argv[1] = "-c";
argv[2] = command_string;
argv[3] = NULL;
/* 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]);
close(pout[1]);
/* Free the command name. */
- buffer_free(&command);
+ xfree(command_string);
/* Set the connection file descriptors. */
packet_set_connection(pout[0], pin[1]);
* Creates a (possibly privileged) socket for use as the ssh connection.
*/
static int
-ssh_create_socket(struct passwd *pw, int privileged, int family)
+ssh_create_socket(int privileged, struct addrinfo *ai)
{
int sock, gaierr;
struct addrinfo hints, *res;
*/
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);
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);
+ sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol);
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 = family;
- hints.ai_socktype = SOCK_STREAM;
+ 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) {
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;
+ int optval, rc, result = -1;
+
+ gettimeofday(&t_start, NULL);
+
+ if (*timeoutp <= 0) {
+ result = connect(sockfd, serv_addr, addrlen);
+ goto done;
+ }
+
+ set_nonblock(sockfd);
+ rc = connect(sockfd, serv_addr, addrlen);
+ if (rc == 0) {
+ unset_nonblock(sockfd);
+ result = 0;
+ goto done;
+ }
+ if (errno != EINPROGRESS) {
+ result = -1;
+ goto done;
+ }
+
+ fdset = (fd_set *)xcalloc(howmany(sockfd + 1, NFDBITS),
+ sizeof(fd_mask));
+ FD_SET(sockfd, fdset);
+ ms_to_timeval(&tv, *timeoutp);
+
+ 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;
+ unset_nonblock(sockfd);
+ break;
+ default:
+ /* Should not occur */
+ fatal("Bogus return (%d) from select()", rc);
+ }
+
+ xfree(fdset);
+
+ done:
+ if (result == 0 && *timeoutp > 0) {
+ ms_subtract_diff(&t_start, timeoutp);
+ if (*timeoutp <= 0) {
+ errno = ETIMEDOUT;
+ result = -1;
+ }
+ }
+
+ 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 family, int connection_attempts,
- int anonymous, struct passwd *pw, const char *proxy_command)
+ u_short port, int family, int connection_attempts, int *timeout_ms,
+ int want_keepalive, int needpriv, const char *proxy_command)
{
int gaierr;
int on = 1;
int sock = -1, attempt;
char ntop[NI_MAXHOST], strport[NI_MAXSERV];
struct addrinfo hints, *ai, *aitop;
- struct linger linger;
- 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 %u geteuid %u anon %d",
- (u_int) getuid(), (u_int) geteuid(), anonymous);
+ debug2("ssh_connect: needpriv %d", needpriv);
- /* Get default port if port has not been set. */
- if (port == 0) {
- sp = getservbyname(SSH_SERVICE_NAME, "tcp");
- if (sp)
- port = ntohs(sp->s_port);
- else
- port = SSH_DEFAULT_PORT;
- }
/* If a proxy command is given, connect using it. */
if (proxy_command != NULL)
- return ssh_proxy_connect(host, port, pw, proxy_command);
+ return ssh_proxy_connect(host, port, proxy_command);
/* No proxy command. */
memset(&hints, 0, sizeof(hints));
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; ;) {
- if (attempt > 0)
+ for (attempt = 0; attempt < connection_attempts; attempt++) {
+ if (attempt > 0) {
+ /* Sleep a moment before retrying. */
+ sleep(1);
debug("Trying again...");
-
- /* Loop through addresses for this host, and try each one in
- sequence until the connection succeeds. */
+ }
+ /*
+ * Loop through addresses for this host, and try each one in
+ * sequence until the connection succeeds.
+ */
for (ai = aitop; ai; ai = ai->ai_next) {
if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6)
continue;
host, ntop, strport);
/* Create a socket for connecting. */
- sock = ssh_create_socket(pw,
-#ifdef HAVE_CYGWIN
- !anonymous,
-#else
- !anonymous && geteuid() == 0,
-#endif
- 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(pw);
- if (connect(sock, ai->ai_addr, ai->ai_addrlen) >= 0) {
+ if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen,
+ timeout_ms) >= 0) {
/* Successful connection. */
memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
- restore_uid();
break;
} else {
- if (errno == ECONNREFUSED)
- full_failure = 0;
- log("ssh: connect to address %s port %s: %s",
- sockaddr_ntop(ai->ai_addr), strport,
- strerror(errno));
- restore_uid();
- /*
- * 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);
+ debug("connect to address %s port %s: %s",
+ ntop, strport, strerror(errno));
close(sock);
+ sock = -1;
}
}
- if (ai)
+ if (sock != -1)
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 full_failure ? ECONNABORTED : ECONNREFUSED;
+ if (sock == -1) {
+ error("ssh: connect to host %s port %s: %s",
+ host, strport, strerror(errno));
+ return (-1);
+ }
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 &&
+ /* Set SO_KEEPALIVE if requested. */
+ if (want_keepalive &&
setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
sizeof(on)) < 0)
error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
* identification string.
*/
static void
-ssh_exchange_identification(void)
+ssh_exchange_identification(int timeout_ms)
{
char buf[256], remote_version[256]; /* must be same size! */
- int remote_major, remote_minor, i, mismatch;
+ int remote_major, remote_minor, 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 (;;) {
+ 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);
+
+ /* Read other side's version identification. */
+ remaining = timeout_ms;
+ for (n = 0;;) {
for (i = 0; i < sizeof(buf) - 1; i++) {
- int len = atomicio(read, connection_in, &buf[i], 1);
- if (len < 0)
- fatal("ssh_exchange_identification: read: %.100s", strerror(errno));
- if (len != 1)
- fatal("ssh_exchange_identification: Connection closed by remote host");
+ if (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));
+ }
+ }
+
+ len = atomicio(read, connection_in, &buf[i], 1);
+
+ if (len != 1 && errno == EPIPE)
+ fatal("ssh_exchange_identification: "
+ "Connection closed by remote host");
+ else if (len != 1)
+ fatal("ssh_exchange_identification: "
+ "read: %.100s", strerror(errno));
if (buf[i] == '\r') {
buf[i] = '\n';
buf[i + 1] = 0;
buf[i + 1] = 0;
break;
}
+ if (++n > 65536)
+ fatal("ssh_exchange_identification: "
+ "No banner received");
}
buf[sizeof(buf) - 1] = 0;
if (strncmp(buf, "SSH-", 4) == 0)
debug("ssh_exchange_identification: %s", buf);
}
server_version_string = xstrdup(buf);
+ xfree(fdset);
/*
* Check that the versions match. In future this might accept
&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) &&
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;
}
}
compat20 ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_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);
static int
confirm(const char *prompt)
{
- char buf[1024];
- FILE *f;
- int retval = -1;
+ const char *msg, *again = "Please type 'yes' or 'no': ";
+ char *p;
+ int ret = -1;
if (options.batch_mode)
return 0;
- if (isatty(STDIN_FILENO))
- f = stdin;
- else
- f = fopen(_PATH_TTY, "rw");
- if (f == NULL)
- return 0;
- fflush(stdout);
- fprintf(stderr, "%s", prompt);
- while (1) {
- if (fgets(buf, sizeof(buf), f) == NULL) {
- fprintf(stderr, "\n");
- strlcpy(buf, "no", sizeof buf);
- }
- /* Remove newline from response. */
- if (strchr(buf, '\n'))
- *strchr(buf, '\n') = 0;
- if (strcmp(buf, "yes") == 0)
- retval = 1;
- else if (strcmp(buf, "no") == 0)
- retval = 0;
- else
- fprintf(stderr, "Please type 'yes' or 'no': ");
-
- 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 -1 if the key
* is not valid. the user_hostfile will not be updated if 'readonly' is true.
*/
-
+#define RDRW 0
+#define RDONLY 1
+#define ROQUIET 2
static int
-check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
- int readonly, const char *user_hostfile, const char *system_hostfile)
+check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port,
+ Key *host_key, int readonly, const char *user_hostfile,
+ const char *system_hostfile)
{
Key *file_key;
- char *type = key_type(host_key);
- char *ip = NULL;
+ const char *type = key_type(host_key);
+ char *ip = NULL, *host = NULL;
char hostline[1000], *hostp, *fp;
HostStatus host_status;
HostStatus ip_status;
- int local = 0, host_ip_differ = 0;
+ int r, local = 0, host_ip_differ = 0;
int salen;
char ntop[NI_MAXHOST];
- int host_line, ip_line;
+ char msg[1024];
+ int len, host_line, ip_line;
const char *host_file = NULL, *ip_file = NULL;
/*
if (getnameinfo(hostaddr, salen, ntop, sizeof(ntop),
NULL, 0, NI_NUMERICHOST) != 0)
fatal("check_host_key: getnameinfo failed");
- ip = xstrdup(ntop);
+ ip = put_host_port(ntop, port);
} 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))
+ if (options.check_host_ip && (local ||
+ strcmp(hostname, 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.
+ * 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 (options.host_key_alias != NULL) {
- host = options.host_key_alias;
+ host = xstrdup(options.host_key_alias);
debug("using hostkeyalias: %s", host);
+ } else {
+ host = put_host_port(hostname, port);
}
/*
file_key = key_new(host_key->type);
/*
- * Check if the host key is present in the user\'s list of known
+ * Check if the host key is present in the user's list of known
* hosts or in the systemwide list.
*/
host_file = user_hostfile;
host_status = check_host_in_hostfile(host_file, host, host_key,
- file_key, &host_line);
+ file_key, &host_line);
if (host_status == HOST_NEW) {
host_file = system_hostfile;
host_status = check_host_in_hostfile(host_file, host, host_key,
debug("Found key in %s:%d", host_file, host_line);
if (options.check_host_ip && ip_status == HOST_NEW) {
if (readonly)
- log("%s host key for IP address "
+ 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))
- log("Failed to add the %s host key for IP "
+ host_key, options.hash_known_hosts))
+ logit("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 "
+ 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 (options.host_key_alias == NULL && port != 0 &&
+ port != SSH_DEFAULT_PORT) {
+ debug("checking without port identifier");
+ if (check_host_key(hostname, hostaddr, 0, host_key, 2,
+ user_hostfile, system_hostfile) == 0) {
+ debug("found matching key w/out port");
+ break;
+ }
+ }
if (readonly)
goto fail;
/* The host is new. */
"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];
fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
- snprintf(prompt, sizeof(prompt),
+ 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.\n"
- "%s key fingerprint is %s.\n"
+ "established%s\n"
+ "%s key fingerprint is %s.\n%s"
"Are you sure you want to continue connecting "
- "(yes/no)? ", host, ip, type, fp);
+ "(yes/no)? ",
+ host, ip, msg1, type, fp, msg2);
xfree(fp);
- if (!confirm(prompt)) {
+ if (!confirm(msg))
goto fail;
- }
}
- 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 (!add_host_to_hostfile(user_hostfile, hostp, host_key))
- log("Failed to add the host to the list of known "
+ if (options.check_host_ip && ip_status == HOST_NEW) {
+ snprintf(hostline, sizeof(hostline), "%s,%s",
+ host, ip);
+ hostp = hostline;
+ if (options.hash_known_hosts) {
+ /* Add hash of host and IP separately */
+ r = add_host_to_hostfile(user_hostfile, host,
+ host_key, options.hash_known_hosts) &&
+ add_host_to_hostfile(user_hostfile, ip,
+ host_key, options.hash_known_hosts);
+ } else {
+ /* Add unhashed "host,ip" */
+ r = add_host_to_hostfile(user_hostfile,
+ hostline, host_key,
+ options.hash_known_hosts);
+ }
+ } else {
+ r = add_host_to_hostfile(user_hostfile, host, host_key,
+ options.hash_known_hosts);
+ hostp = host;
+ }
+
+ if (!r)
+ logit("Failed to add the host to the list of known "
"hosts (%.500s).", user_hostfile);
else
- log("Warning: Permanently added '%.200s' (%s) to the "
+ logit("Warning: Permanently added '%.200s' (%s) to the "
"list of known hosts.", hostp, type);
break;
case HOST_CHANGED:
+ if (readonly == ROQUIET)
+ goto fail;
if (options.check_host_ip && host_ip_differ) {
- char *msg;
+ char *key_msg;
if (ip_status == HOST_NEW)
- msg = "is unknown";
+ key_msg = "is unknown";
else if (ip_status == HOST_OK)
- msg = "is unchanged";
+ key_msg = "is unchanged";
else
- msg = "has a different value";
+ 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);
error("and the key for the according IP address %s", ip);
- error("%s. This could either mean that", msg);
+ error("%s. This could either mean that", key_msg);
error("DNS SPOOFING is happening or the IP address for the host");
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.");
+ warn_changed_key(host_key);
error("Add correct host key in %.100s to get rid of this message.",
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
/*
* If strict host key checking has not been requested, allow
- * the connection but without password authentication or
- * agent forwarding.
+ * the connection but without MITM-able authentication or
+ * forwarding.
*/
if (options.password_authentication) {
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 "
"man-in-the-middle attacks.");
error("Port forwarding is disabled to avoid "
"man-in-the-middle attacks.");
options.num_local_forwards =
- options.num_remote_forwards = 0;
+ options.num_remote_forwards = 0;
+ }
+ 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;
}
/*
* XXX Should permit the user to change to use the new id.
* accept the authentication.
*/
break;
+ case HOST_FOUND:
+ fatal("internal error");
+ break;
}
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);
+ 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) {
- if (!confirm("Are you sure you want "
- "to continue connecting (yes/no)? ")) {
+ 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);
+ xfree(host);
return 0;
fail:
xfree(ip);
+ xfree(host);
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.");
+ }
+ }
+ }
/* 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)
+ if (check_host_key(host, hostaddr, options.port, host_key,
+ RDONLY, 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);
+ return check_host_key(host, hostaddr, options.port, host_key,
+ RDRW, options.user_hostfile, options.system_hostfile);
}
/*
* This function does not require super-user privileges.
*/
void
-ssh_login(Key **keys, int nkeys, const char *orighost,
- struct sockaddr *hostaddr, struct passwd *pw)
+ssh_login(Sensitive *sensitive, const char *orighost,
+ struct sockaddr *hostaddr, struct passwd *pw, int timeout_ms)
{
char *host, *cp;
char *server_user, *local_user;
host = xstrdup(orighost);
for (cp = host; *cp; cp++)
if (isupper(*cp))
- *cp = tolower(*cp);
+ *cp = (char)tolower(*cp);
/* Exchange protocol version identification strings with the server. */
- ssh_exchange_identification();
+ ssh_exchange_identification(timeout_ms);
/* Put the connection into non-blocking mode. */
packet_set_nonblocking();
/* authenticate user */
if (compat20) {
ssh_kex2(host, hostaddr);
- ssh_userauth2(local_user, server_user, host, keys, nkeys);
+ ssh_userauth2(local_user, server_user, host, sensitive);
} else {
ssh_kex(host, hostaddr);
- ssh_userauth1(local_user, server_user, host, keys, nkeys);
+ ssh_userauth1(local_user, server_user, host, sensitive);
}
+ xfree(local_user);
}
void
return;
}
size = roundup(strlen(password) + 1, 32);
- padded = xmalloc(size);
- memset(padded, 0, size);
+ padded = xcalloc(1, 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);
+}
+
+/*
+ * Execute a local command
+ */
+int
+ssh_local_cmd(const char *args)
+{
+ char *shell;
+ pid_t pid;
+ int status;
+
+ if (!options.permit_local_command ||
+ args == NULL || !*args)
+ return (1);
+
+ if ((shell = getenv("SHELL")) == NULL)
+ shell = _PATH_BSHELL;
+
+ pid = fork();
+ if (pid == 0) {
+ 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));
+
+ if (!WIFEXITED(status))
+ return (1);
+
+ return (WEXITSTATUS(status));
+}