*/
#include "includes.h"
-RCSID("$OpenBSD: sshconnect.c,v 1.110 2001/07/25 14:35:18 markus Exp $");
+RCSID("$OpenBSD: sshconnect.c,v 1.145 2003/06/11 10:16:16 jakob Exp $");
#include <openssl/bn.h>
#include "readconf.h"
#include "atomicio.h"
#include "misc.h"
+#include "readpass.h"
+
+#ifdef DNS
+#include "dns.h"
+#endif
char *client_version_string = NULL;
char *server_version_string = NULL;
+#ifdef DNS
+int verified_host_key_dns = 0;
+#endif
+
+/* import */
extern Options options;
extern char *__progname;
-
-/* AF_UNSPEC or AF_INET or AF_INET6 */
-extern int IPv4or6;
+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)
-{
- void *addr;
- static char addrbuf[INET6_ADDRSTRLEN];
-
- 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;
-}
+static int show_other_keys(const char *, Key *);
/*
* 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;
/* 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(pw);
+ seteuid(original_real_uid);
+ setuid(original_real_uid);
/* Redirect stdin and stdout. */
close(pin[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]);
* 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 = IPv4or6;
- 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 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
*/
int
ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
- u_short port, int connection_attempts,
- int anonymous, struct passwd *pw,
- 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;
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
*/
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) {
}
/* 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 = 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));
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,
+ options.connection_timeout) >= 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();
+ 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);
}
}
freeaddrinfo(aitop);
/* Return failure if we didn't get a successful connection. */
- if (attempt >= connection_attempts)
+ 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,
&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;
}
}
/* defaults to 'no' */
static int
-read_yes_or_no(const char *prompt, int defval)
+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);
-
- 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;
- else if (strcmp(buf, "no") == 0)
- retval = 0;
- else
- fprintf(stderr, "Please type 'yes' or 'no'.\n");
-
- 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.
*/
-
static int
check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
int readonly, const char *user_hostfile, const char *system_hostfile)
int 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;
/*
switch (hostaddr->sa_family) {
case AF_INET:
local = (ntohl(((struct sockaddr_in *)hostaddr)->
- sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
+ sin_addr.s_addr) >> 24) == IN_LOOPBACKNET;
salen = sizeof(struct sockaddr_in);
break;
case AF_INET6:
salen = sizeof(struct sockaddr_storage);
break;
}
- if (local && options.host_key_alias == NULL) {
+ 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;
*/
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))
+ 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);
}
"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';
+#ifdef DNS
+ if (options.verify_host_key_dns) {
+ if (verified_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");
+ }
+#endif
+ 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 (!read_yes_or_no(prompt, -1)) {
- log("Aborted by user!");
+ if (!confirm(msg))
goto fail;
- }
}
if (options.check_host_ip && ip_status == HOST_NEW) {
snprintf(hostline, sizeof(hostline), "%s,%s", host, ip);
* 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 "
+ 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 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) {
"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;
}
/*
* 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 (!read_yes_or_no("Are you sure you want "
- "to continue connecting (yes/no)? ", -1)) {
- log("Aborted by user!");
+ strlcat(msg, "\nAre you sure you want "
+ "to continue connecting (yes/no)? ", sizeof(msg));
+ if (!confirm(msg))
goto fail;
- }
+ } else {
+ logit("%s", msg);
}
}
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;
+#ifdef DNS
+ if (options.verify_host_key_dns) {
+ switch(verify_host_key_dns(host, hostaddr, host_key)) {
+ case DNS_VERIFY_OK:
+#ifdef DNSSEC
+ return 0;
+#else
+ verified_host_key_dns = 1;
+ break;
+#endif
+ case DNS_VERIFY_FAILED:
+ return -1;
+ case DNS_VERIFY_ERROR:
+ break;
+ default:
+ debug3("bad return value from verify_host_key_dns");
+ break;
+ }
+ }
+#endif /* DNS */
+
/* 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) {
* This function does not require super-user privileges.
*/
void
-ssh_login(Key **keys, int nkeys, const char *orighost,
+ssh_login(Sensitive *sensitive, const char *orighost,
struct sockaddr *hostaddr, struct passwd *pw)
{
char *host, *cp;
/* 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);
}
}
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);
+}
andersk / openssh.git / blobdiff