]> andersk Git - openssh.git/blobdiff - sshconnect.c
- markus@cvs.openbsd.org 2005/06/16 08:00:00
[openssh.git] / sshconnect.c
index 3c8f480eda4b881e0c8307e70763f6a23e735dc0..0bd351f6b26aecf7b46813f3706e9fa901df5a75 100644 (file)
@@ -13,7 +13,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: sshconnect.c,v 1.150 2003/11/03 09:09:41 jakob Exp $");
+RCSID("$OpenBSD: sshconnect.c,v 1.164 2005/06/06 11:20:36 djm Exp $");
 
 #include <openssl/bn.h>
 
@@ -31,14 +31,13 @@ RCSID("$OpenBSD: sshconnect.c,v 1.150 2003/11/03 09:09:41 jakob Exp $");
 #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 verified_host_key_dns = 0;
+int matching_host_key_dns = 0;
 
 /* import */
 extern Options options;
@@ -60,12 +59,11 @@ static void warn_changed_key(Key *);
 static int
 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];
+       size_t len;
 
        /* Convert the port number into a string. */
        snprintf(strport, sizeof strport, "%hu", port);
@@ -74,34 +72,16 @@ ssh_proxy_connect(const char *host, u_short port, const char *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 
+        * 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);
-                       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);
+       len = strlen(proxy_command) + 6;
+       tmp = xmalloc(len);
+       strlcpy(tmp, "exec ", len);
+       strlcat(tmp, proxy_command, len);
+       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)
@@ -155,7 +135,7 @@ ssh_proxy_connect(const char *host, u_short port, const char *proxy_command)
        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]);
@@ -231,12 +211,12 @@ timeout_connect(int sockfd, const struct sockaddr *serv_addr,
        if (timeout <= 0)
                return (connect(sockfd, serv_addr, addrlen));
 
-       if (fcntl(sockfd, F_SETFL, O_NONBLOCK) < 0)
-               return (-1);
-
+       set_nonblock(sockfd);
        rc = connect(sockfd, serv_addr, addrlen);
-       if (rc == 0)
+       if (rc == 0) {
+               unset_nonblock(sockfd);
                return (0);
+       }
        if (errno != EINPROGRESS)
                return (-1);
 
@@ -248,28 +228,28 @@ timeout_connect(int sockfd, const struct sockaddr *serv_addr,
        tv.tv_sec = timeout;
        tv.tv_usec = 0;
 
-       for(;;) {
+       for (;;) {
                rc = select(sockfd + 1, NULL, fdset, NULL, &tv);
                if (rc != -1 || errno != EINTR)
                        break;
        }
 
-       switch(rc) {
+       switch (rc) {
        case 0:
                /* Timed out */
                errno = ETIMEDOUT;
                break;
        case -1:
                /* Select error */
-               debug("select: %s", strerror(errno));
+               debug("select: %s", strerror(errno));
                break;
        case 1:
                /* Completed or failed */
                optval = 0;
                optlen = sizeof(optval);
-               if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval, 
+               if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval,
                    &optlen) == -1) {
-                       debug("getsockopt: %s", strerror(errno));
+                       debug("getsockopt: %s", strerror(errno));
                        break;
                }
                if (optval != 0) {
@@ -277,6 +257,7 @@ timeout_connect(int sockfd, const struct sockaddr *serv_addr,
                        break;
                }
                result = 0;
+               unset_nonblock(sockfd);
                break;
        default:
                /* Should not occur */
@@ -297,12 +278,6 @@ timeout_connect(int sockfd, const struct sockaddr *serv_addr,
  * 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,
@@ -315,12 +290,6 @@ ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
        char ntop[NI_MAXHOST], strport[NI_MAXSERV];
        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;
 
        debug2("ssh_connect: needpriv %d", needpriv);
 
@@ -381,8 +350,6 @@ ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
                                memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen);
                                break;
                        } else {
-                               if (errno == ECONNREFUSED)
-                                       full_failure = 0;
                                debug("connect to address %s port %s: %s",
                                    ntop, strport, strerror(errno));
                                /*
@@ -408,15 +375,15 @@ ssh_connect(const char *host, struct sockaddr_storage * hostaddr,
 
        /* Return failure if we didn't get a successful connection. */
        if (attempt >= connection_attempts) {
-               logit("ssh: connect to host %s port %s: %s",
+               error("ssh: connect to host %s port %s: %s",
                    host, strport, strerror(errno));
-               return full_failure ? ECONNABORTED : ECONNREFUSED;
+               return (-1);
        }
 
        debug("Connection established.");
 
-       /* Set keepalives if requested. */
-       if (options.keepalives &&
+       /* Set SO_KEEPALIVE if requested. */
+       if (options.tcp_keep_alive &&
            setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on,
            sizeof(on)) < 0)
                error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
@@ -440,14 +407,15 @@ ssh_exchange_identification(void)
        int connection_out = packet_get_connection_out();
        int minor1 = PROTOCOL_MINOR_1;
 
-       /* Read other side\'s version identification. */
+       /* Read other side's version identification. */
        for (;;) {
                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)
+                       size_t 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;
@@ -563,12 +531,12 @@ check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
     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, *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];
        char msg[1024];
@@ -692,7 +660,7 @@ check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
                                    "'%.128s' not in list of known hosts.",
                                    type, ip);
                        else if (!add_host_to_hostfile(user_hostfile, ip,
-                           host_key))
+                           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);
@@ -728,7 +696,7 @@ check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
                        fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
                        msg2[0] = '\0';
                        if (options.verify_host_key_dns) {
-                               if (verified_host_key_dns)
+                               if (matching_host_key_dns)
                                        snprintf(msg2, sizeof(msg2),
                                            "Matching host key fingerprint"
                                            " found in DNS.\n");
@@ -748,17 +716,33 @@ check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
                        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))
+               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
@@ -767,19 +751,19 @@ check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key,
                break;
        case HOST_CHANGED:
                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)
@@ -892,23 +876,25 @@ int
 verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key)
 {
        struct stat st;
+       int flags = 0;
 
-       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;
+       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.");
+                       }
                }
        }
 
@@ -1041,7 +1027,7 @@ static void
 warn_changed_key(Key *host_key)
 {
        char *fp;
-       char *type = key_type(host_key);
+       const char *type = key_type(host_key);
 
        fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX);
 
@@ -1056,5 +1042,4 @@ warn_changed_key(Key *host_key)
        error("Please contact your system administrator.");
 
        xfree(fp);
-       xfree(type);
 }
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