]> andersk Git - openssh.git/blobdiff - ssh.c
- markus@cvs.openbsd.org 2002/07/03 14:21:05
[openssh.git] / ssh.c
diff --git a/ssh.c b/ssh.c
index 2984a597fb88c200042e137c9f62ae49ea24414a..77e709dafad876b28c95b0db65ac2052edd1d3b9 100644 (file)
--- a/ssh.c
+++ b/ssh.c
@@ -13,6 +13,7 @@
  * called by a name other than "ssh" or "Secure Shell".
  *
  * Copyright (c) 1999 Niels Provos.  All rights reserved.
+ * Copyright (c) 2000, 2001, 2002 Markus Friedl.  All rights reserved.
  *
  * Modified to work with SSL by Niels Provos <provos@citi.umich.edu>
  * in Canada (German citizen).
@@ -39,7 +40,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: ssh.c,v 1.149 2001/10/24 08:51:35 markus Exp $");
+RCSID("$OpenBSD: ssh.c,v 1.181 2002/07/03 14:21:05 markus Exp $");
 
 #include <openssl/evp.h>
 #include <openssl/err.h>
@@ -52,7 +53,6 @@ RCSID("$OpenBSD: ssh.c,v 1.149 2001/10/24 08:51:35 markus Exp $");
 #include "xmalloc.h"
 #include "packet.h"
 #include "buffer.h"
-#include "uidswap.h"
 #include "channels.h"
 #include "key.h"
 #include "authfd.h"
@@ -70,7 +70,6 @@ RCSID("$OpenBSD: ssh.c,v 1.149 2001/10/24 08:51:35 markus Exp $");
 #include "sshtty.h"
 
 #ifdef SMARTCARD
-#include <openssl/engine.h>
 #include "scard.h"
 #endif
 
@@ -107,7 +106,7 @@ int stdin_null_flag = 0;
 
 /*
  * Flag indicating that ssh should fork after authentication.  This is useful
- * so that the pasphrase can be entered manually, and then ssh goes to the
+ * so that the passphrase can be entered manually, and then ssh goes to the
  * background.
  */
 int fork_after_authentication_flag = 0;
@@ -132,13 +131,11 @@ char *host;
 struct sockaddr_storage hostaddr;
 
 /* Private host keys. */
-struct {
-       Key     **keys;
-       int     nkeys;
-} sensitive_data;
+Sensitive sensitive_data;
 
 /* Original real UID. */
 uid_t original_real_uid;
+uid_t original_effective_uid;
 
 /* command to be executed */
 Buffer command;
@@ -146,6 +143,9 @@ Buffer command;
 /* Should we execute a command or invoke a subsystem? */
 int subsystem_flag = 0;
 
+/* # of replies received for global requests */
+static int client_global_request_id = 0;
+
 /* Prints a help message to the user.  This function never returns. */
 
 static void
@@ -200,44 +200,6 @@ usage(void)
        exit(1);
 }
 
-/*
- * Connects to the given host using rsh (or prints an error message and exits
- * if rsh is not available).  This function never returns.
- */
-static void
-rsh_connect(char *host, char *user, Buffer * command)
-{
-       char *args[10];
-       int i;
-
-       log("Using rsh.  WARNING: Connection will not be encrypted.");
-       /* Build argument list for rsh. */
-       i = 0;
-       args[i++] = _PATH_RSH;
-       /* host may have to come after user on some systems */
-       args[i++] = host;
-       if (user) {
-               args[i++] = "-l";
-               args[i++] = user;
-       }
-       if (buffer_len(command) > 0) {
-               buffer_append(command, "\0", 1);
-               args[i++] = buffer_ptr(command);
-       }
-       args[i++] = NULL;
-       if (debug_flag) {
-               for (i = 0; args[i]; i++) {
-                       if (i != 0)
-                               fprintf(stderr, " ");
-                       fprintf(stderr, "%s", args[i]);
-               }
-               fprintf(stderr, "\n");
-       }
-       execv(_PATH_RSH, args);
-       perror(_PATH_RSH);
-       exit(1);
-}
-
 static int ssh_session(void);
 static int ssh_session2(void);
 static void load_public_identity_files(void);
@@ -248,14 +210,13 @@ static void load_public_identity_files(void);
 int
 main(int ac, char **av)
 {
-       int i, opt, exit_status, cerr;
+       int i, opt, exit_status;
        u_short fwd_port, fwd_host_port;
        char sfwd_port[6], sfwd_host_port[6];
        char *p, *cp, buf[256];
        struct stat st;
        struct passwd *pw;
        int dummy;
-       uid_t original_effective_uid;
        extern int optind, optreset;
        extern char *optarg;
 
@@ -294,7 +255,7 @@ main(int ac, char **av)
         * them when the port has been created (actually, when the connection
         * has been made, as we may need to create the port several times).
         */
-       temporarily_use_uid(pw);
+       PRIV_END;
 
        /*
         * Set our umask to something reasonable, as some files are created
@@ -475,7 +436,7 @@ again:
                                /* NOTREACHED */
                        }
                        if ((fwd_port = a2port(sfwd_port)) == 0 ||
-                           (fwd_host_port = a2port(sfwd_host_port)) == 0) {
+                           (fwd_host_port = a2port(sfwd_host_port)) == 0) {
                                fprintf(stderr,
                                    "Bad forwarding port(s) '%s'\n", optarg);
                                exit(1);
@@ -485,7 +446,7 @@ again:
                                    fwd_host_port);
                        else if (opt == 'R')
                                add_remote_forward(&options, fwd_port, buf,
-                                    fwd_host_port);
+                                   fwd_host_port);
                        break;
 
                case 'D':
@@ -591,7 +552,7 @@ again:
        if (buffer_len(&command) == 0)
                tty_flag = 1;
 
-       /* Force no tty*/
+       /* Force no tty */
        if (no_tty_flag)
                tty_flag = 0;
        /* Do not allocate a tty if stdin is not a tty. */
@@ -650,52 +611,54 @@ again:
                    "originating port will not be trusted.");
                options.rhosts_authentication = 0;
        }
-       /*
-        * If using rsh has been selected, exec it now (without trying
-        * anything else).  Note that we must release privileges first.
-        */
-       if (options.use_rsh) {
-               /*
-                * Restore our superuser privileges.  This must be done
-                * before permanently setting the uid.
-                */
-               restore_uid();
-
-               /* Switch to the original uid permanently. */
-               permanently_set_uid(pw);
-
-               /* Execute rsh. */
-               rsh_connect(host, options.user, &command);
-               fatal("rsh_connect returned");
-       }
-       /* Restore our superuser privileges. */
-       restore_uid();
-
        /* Open a connection to the remote host. */
 
-       cerr = ssh_connect(host, &hostaddr, options.port, IPv4or6,
+       if (ssh_connect(host, &hostaddr, options.port, IPv4or6,
            options.connection_attempts,
-           original_effective_uid != 0 || !options.use_privileged_port,
-           pw, options.proxy_command);
+#ifdef HAVE_CYGWIN
+           options.use_privileged_port,
+#else
+           original_effective_uid == 0 && options.use_privileged_port,
+#endif
+           options.proxy_command) != 0)
+               exit(1);
 
        /*
         * If we successfully made the connection, load the host private key
         * in case we will need it later for combined rsa-rhosts
         * authentication. This must be done before releasing extra
         * privileges, because the file is only readable by root.
+        * If we cannot access the private keys, load the public keys
+        * instead and try to execute the ssh-keysign helper instead.
         */
        sensitive_data.nkeys = 0;
        sensitive_data.keys = NULL;
-       if (!cerr && (options.rhosts_rsa_authentication ||
-           options.hostbased_authentication)) {
+       sensitive_data.external_keysign = 0;
+       if (options.rhosts_rsa_authentication ||
+           options.hostbased_authentication) {
                sensitive_data.nkeys = 3;
-               sensitive_data.keys = xmalloc(sensitive_data.nkeys*sizeof(Key));
+               sensitive_data.keys = xmalloc(sensitive_data.nkeys *
+                   sizeof(Key));
+
+               PRIV_START;
                sensitive_data.keys[0] = key_load_private_type(KEY_RSA1,
                    _PATH_HOST_KEY_FILE, "", NULL);
                sensitive_data.keys[1] = key_load_private_type(KEY_DSA,
                    _PATH_HOST_DSA_KEY_FILE, "", NULL);
                sensitive_data.keys[2] = key_load_private_type(KEY_RSA,
                    _PATH_HOST_RSA_KEY_FILE, "", NULL);
+               PRIV_END;
+
+               if (options.hostbased_authentication == 1 &&
+                   sensitive_data.keys[0] == NULL &&
+                   sensitive_data.keys[1] == NULL &&
+                   sensitive_data.keys[2] == NULL) {
+                       sensitive_data.keys[1] = key_load_public(
+                           _PATH_HOST_DSA_KEY_FILE, NULL);
+                       sensitive_data.keys[2] = key_load_public(
+                           _PATH_HOST_RSA_KEY_FILE, NULL);
+                       sensitive_data.external_keysign = 1;
+               }
        }
        /*
         * Get rid of any extra privileges that we may have.  We will no
@@ -704,15 +667,8 @@ again:
         * user's home directory if it happens to be on a NFS volume where
         * root is mapped to nobody.
         */
-
-       /*
-        * Note that some legacy systems need to postpone the following call
-        * to permanently_set_uid() until the private hostkey is destroyed
-        * with RSA_free().  Otherwise the calling user could ptrace() the
-        * process, read the private hostkey and impersonate the host.
-        * OpenBSD does not allow ptracing of setuid processes.
-        */
-       permanently_set_uid(pw);
+       seteuid(original_real_uid);
+       setuid(original_real_uid);
 
        /*
         * Now that we are back to our own permissions, create ~/.ssh
@@ -723,21 +679,6 @@ again:
                if (mkdir(buf, 0700) < 0)
                        error("Could not create directory '%.200s'.", buf);
 
-       /* Check if the connection failed, and try "rsh" if appropriate. */
-       if (cerr) {
-               if (!options.fallback_to_rsh)
-                       exit(1);
-               if (options.port != 0)
-                       log("Secure connection to %.100s on port %hu refused; "
-                           "reverting to insecure method",
-                           host, options.port);
-               else
-                       log("Secure connection to %.100s refused; "
-                           "reverting to insecure method.", host);
-
-               rsh_connect(host, options.user, &command);
-               fatal("rsh_connect returned");
-       }
        /* load options.identity_files */
        load_public_identity_files();
 
@@ -755,8 +696,7 @@ again:
        signal(SIGPIPE, SIG_IGN); /* ignore SIGPIPE early */
 
        /* Log into the remote system.  This never returns if the login fails. */
-       ssh_login(sensitive_data.keys, sensitive_data.nkeys,
-           host, (struct sockaddr *)&hostaddr, pw);
+       ssh_login(&sensitive_data, host, (struct sockaddr *)&hostaddr, pw);
 
        /* We no longer need the private host keys.  Clear them now. */
        if (sensitive_data.nkeys != 0) {
@@ -787,19 +727,36 @@ again:
 }
 
 static void
-x11_get_proto(char *proto, int proto_len, char *data, int data_len)
+x11_get_proto(char **_proto, char **_data)
 {
        char line[512];
+       static char proto[512], data[512];
        FILE *f;
        int got_data = 0, i;
+       char *display;
 
-       if (options.xauth_location) {
+       *_proto = proto;
+       *_data = data;
+       proto[0] = data[0] = '\0';
+       if (options.xauth_location && (display = getenv("DISPLAY"))) {
                /* Try to get Xauthority information for the display. */
-               snprintf(line, sizeof line, "%.100s list %.200s 2>" _PATH_DEVNULL,
-                   options.xauth_location, getenv("DISPLAY"));
+               if (strncmp(display, "localhost:", 10) == 0)
+                       /*
+                        * Handle FamilyLocal case where $DISPLAY does
+                        * not match an authorization entry.  For this we
+                        * just try "xauth list unix:displaynum.screennum".
+                        * XXX: "localhost" match to determine FamilyLocal
+                        *      is not perfect.
+                        */
+                       snprintf(line, sizeof line, "%s list unix:%s 2>"
+                           _PATH_DEVNULL, options.xauth_location, display+10);
+               else
+                       snprintf(line, sizeof line, "%s list %.200s 2>"
+                           _PATH_DEVNULL, options.xauth_location, display);
+               debug2("x11_get_proto %s", line);
                f = popen(line, "r");
                if (f && fgets(line, sizeof(line), f) &&
-                   sscanf(line, "%*s %s %s", proto, data) == 2)
+                   sscanf(line, "%*s %511s %511s", proto, data) == 2)
                        got_data = 1;
                if (f)
                        pclose(f);
@@ -815,11 +772,11 @@ x11_get_proto(char *proto, int proto_len, char *data, int data_len)
        if (!got_data) {
                u_int32_t rand = 0;
 
-               strlcpy(proto, "MIT-MAGIC-COOKIE-1", proto_len);
+               strlcpy(proto, "MIT-MAGIC-COOKIE-1", sizeof proto);
                for (i = 0; i < 16; i++) {
                        if (i % 4 == 0)
                                rand = arc4random();
-                       snprintf(data + 2 * i, data_len - 2 * i, "%02x", rand & 0xff);
+                       snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", rand & 0xff);
                        rand >>= 8;
                }
        }
@@ -837,7 +794,7 @@ ssh_init_forwarding(void)
                    options.local_forwards[i].port,
                    options.local_forwards[i].host,
                    options.local_forwards[i].host_port);
-               success += channel_request_local_forwarding(
+               success += channel_setup_local_fwd_listener(
                    options.local_forwards[i].port,
                    options.local_forwards[i].host,
                    options.local_forwards[i].host_port,
@@ -876,7 +833,6 @@ static int
 ssh_session(void)
 {
        int type;
-       int plen;
        int interactive = 0;
        int have_tty = 0;
        struct winsize ws;
@@ -894,7 +850,7 @@ ssh_session(void)
                packet_put_int(options.compression_level);
                packet_send();
                packet_write_wait();
-               type = packet_read(&plen);
+               type = packet_read();
                if (type == SSH_SMSG_SUCCESS)
                        packet_start_compression(options.compression_level);
                else if (type == SSH_SMSG_FAILURE)
@@ -932,7 +888,7 @@ ssh_session(void)
                packet_write_wait();
 
                /* Read response from the server. */
-               type = packet_read(&plen);
+               type = packet_read();
                if (type == SSH_SMSG_SUCCESS) {
                        interactive = 1;
                        have_tty = 1;
@@ -943,15 +899,15 @@ ssh_session(void)
        }
        /* Request X11 forwarding if enabled and DISPLAY is set. */
        if (options.forward_x11 && getenv("DISPLAY") != NULL) {
-               char proto[512], data[512];
+               char *proto, *data;
                /* Get reasonable local authentication information. */
-               x11_get_proto(proto, sizeof proto, data, sizeof data);
+               x11_get_proto(&proto, &data);
                /* Request forwarding with authentication spoofing. */
                debug("Requesting X11 forwarding with authentication spoofing.");
                x11_request_forwarding_with_spoofing(0, proto, data);
 
                /* Read response from the server. */
-               type = packet_read(&plen);
+               type = packet_read();
                if (type == SSH_SMSG_SUCCESS) {
                        interactive = 1;
                } else if (type == SSH_SMSG_FAILURE) {
@@ -971,8 +927,8 @@ ssh_session(void)
                auth_request_forwarding();
 
                /* Read response from the server. */
-               type = packet_read(&plen);
-               packet_integrity_check(plen, 0, type);
+               type = packet_read();
+               packet_check_eom();
                if (type != SSH_SMSG_SUCCESS)
                        log("Warning: Remote host denied authentication agent forwarding.");
        }
@@ -993,7 +949,7 @@ ssh_session(void)
                int len = buffer_len(&command);
                if (len > 900)
                        len = 900;
-               debug("Sending command: %.*s", len, buffer_ptr(&command));
+               debug("Sending command: %.*s", len, (u_char *)buffer_ptr(&command));
                packet_start(SSH_CMSG_EXEC_CMD);
                packet_put_string(buffer_ptr(&command), buffer_len(&command));
                packet_send();
@@ -1011,7 +967,7 @@ ssh_session(void)
 }
 
 static void
-client_subsystem_reply(int type, int plen, void *ctxt)
+client_subsystem_reply(int type, u_int32_t seq, void *ctxt)
 {
        int id, len;
 
@@ -1019,10 +975,31 @@ client_subsystem_reply(int type, int plen, void *ctxt)
        len = buffer_len(&command);
        if (len > 900)
                len = 900;
-       packet_done();
+       packet_check_eom();
        if (type == SSH2_MSG_CHANNEL_FAILURE)
                fatal("Request for subsystem '%.*s' failed on channel %d",
-                   len, buffer_ptr(&command), id);
+                   len, (u_char *)buffer_ptr(&command), id);
+}
+
+void
+client_global_request_reply(int type, u_int32_t seq, void *ctxt)
+{
+       int i;
+
+       i = client_global_request_id++;
+       if (i >= options.num_remote_forwards) {
+               debug("client_global_request_reply: too many replies %d > %d",
+                   i, options.num_remote_forwards);
+               return;
+       }
+       debug("remote forward %s for: listen %d, connect %s:%d",
+           type == SSH2_MSG_REQUEST_SUCCESS ? "success" : "failure",
+           options.remote_forwards[i].port,
+           options.remote_forwards[i].host,
+           options.remote_forwards[i].host_port);
+       if (type == SSH2_MSG_REQUEST_FAILURE)
+               log("Warning: remote port forwarding failed for listen port %d",
+                   options.remote_forwards[i].port);
 }
 
 /* request pty/x11/agent/tcpfwd/shell for channel */
@@ -1059,9 +1036,9 @@ ssh_session2_setup(int id, void *arg)
        }
        if (options.forward_x11 &&
            getenv("DISPLAY") != NULL) {
-               char proto[512], data[512];
+               char *proto, *data;
                /* Get reasonable local authentication information. */
-               x11_get_proto(proto, sizeof proto, data, sizeof data);
+               x11_get_proto(&proto, &data);
                /* Request forwarding with authentication spoofing. */
                debug("Requesting X11 forwarding with authentication spoofing.");
                x11_request_forwarding_with_spoofing(id, proto, data);
@@ -1081,24 +1058,23 @@ ssh_session2_setup(int id, void *arg)
                if (len > 900)
                        len = 900;
                if (subsystem_flag) {
-                       debug("Sending subsystem: %.*s", len, buffer_ptr(&command));
+                       debug("Sending subsystem: %.*s", len, (u_char *)buffer_ptr(&command));
                        channel_request_start(id, "subsystem", /*want reply*/ 1);
                        /* register callback for reply */
-                       /* XXX we asume that client_loop has already been called */
+                       /* XXX we assume that client_loop has already been called */
                        dispatch_set(SSH2_MSG_CHANNEL_FAILURE, &client_subsystem_reply);
                        dispatch_set(SSH2_MSG_CHANNEL_SUCCESS, &client_subsystem_reply);
                } else {
-                       debug("Sending command: %.*s", len, buffer_ptr(&command));
+                       debug("Sending command: %.*s", len, (u_char *)buffer_ptr(&command));
                        channel_request_start(id, "exec", 0);
                }
                packet_put_string(buffer_ptr(&command), buffer_len(&command));
                packet_send();
        } else {
-               channel_request(id, "shell", 0);
+               channel_request_start(id, "shell", 0);
+               packet_send();
        }
-       /* channel_callback(id, SSH2_MSG_OPEN_CONFIGMATION, client_init, 0); */
 
-       /* register different callback, etc. XXX */
        packet_set_interactive(interactive);
 }
 
@@ -1130,24 +1106,20 @@ ssh_session2_open(void)
 
        window = CHAN_SES_WINDOW_DEFAULT;
        packetmax = CHAN_SES_PACKET_DEFAULT;
-       if (!tty_flag) {
-               window *= 2;
-               packetmax *=2;
+       if (tty_flag) {
+               window >>= 1;
+               packetmax >>= 1;
        }
        c = channel_new(
            "session", SSH_CHANNEL_OPENING, in, out, err,
            window, packetmax, CHAN_EXTENDED_WRITE,
            xstrdup("client-session"), /*nonblock*/0);
-       if (c == NULL)
-               fatal("ssh_session2_open: channel_new failed");
 
        debug3("ssh_session2_open: channel_new: %d", c->self);
 
        channel_send_open(c->self);
        if (!no_shell_flag)
-               channel_register_callback(c->self,
-                    SSH2_MSG_CHANNEL_OPEN_CONFIRMATION,
-                    ssh_session2_setup, (void *)0);
+               channel_register_confirm(c->self, ssh_session2_setup);
 
        return c->self;
 }
@@ -1176,40 +1148,29 @@ static void
 load_public_identity_files(void)
 {
        char *filename;
-       Key *public;
        int i = 0;
-
+       Key *public;
 #ifdef SMARTCARD
+       Key **keys;
+
        if (options.smartcard_device != NULL &&
-           options.num_identity_files + 1 < SSH_MAX_IDENTITY_FILES &&
-           (public = sc_get_key(options.smartcard_device)) != NULL ) {
-               Key *new;
-
-               if (options.num_identity_files + 2 > SSH_MAX_IDENTITY_FILES)
-                       options.num_identity_files = SSH_MAX_IDENTITY_FILES - 2;
-               memmove(&options.identity_files[2], &options.identity_files[0],
-                   sizeof(char *) * options.num_identity_files);
-               options.num_identity_files += 2;
-               i = 2;
-
-               /* XXX ssh1 vs ssh2 */
-               new = key_new(KEY_RSA);
-               new->flags = KEY_FLAG_EXT;
-               BN_copy(new->rsa->n, public->rsa->n);
-               BN_copy(new->rsa->e, public->rsa->e);
-               RSA_set_method(new->rsa, sc_get_engine());
-               options.identity_keys[0] = new;
-               options.identity_files[0] = xstrdup("smartcard rsa key");;
-
-               new = key_new(KEY_RSA1);
-               new->flags = KEY_FLAG_EXT;
-               BN_copy(new->rsa->n, public->rsa->n);
-               BN_copy(new->rsa->e, public->rsa->e);
-               RSA_set_method(new->rsa, sc_get_engine());
-               options.identity_keys[1] = new;
-               options.identity_files[1] = xstrdup("smartcard rsa1 key");
-
-               key_free(public);
+           options.num_identity_files < SSH_MAX_IDENTITY_FILES &&
+           (keys = sc_get_keys(options.smartcard_device, NULL)) != NULL ) {
+               int count = 0;
+               for (i = 0; keys[i] != NULL; i++) {
+                       count++;
+                       memmove(&options.identity_files[1], &options.identity_files[0],
+                           sizeof(char *) * (SSH_MAX_IDENTITY_FILES - 1));
+                       memmove(&options.identity_keys[1], &options.identity_keys[0],
+                           sizeof(Key *) * (SSH_MAX_IDENTITY_FILES - 1));
+                       options.num_identity_files++;
+                       options.identity_keys[0] = keys[i];
+                       options.identity_files[0] = xstrdup("smartcard key");;
+               }
+               if (options.num_identity_files > SSH_MAX_IDENTITY_FILES)
+                       options.num_identity_files = SSH_MAX_IDENTITY_FILES;
+               i = count;
+               xfree(keys);
        }
 #endif /* SMARTCARD */
        for (; i < options.num_identity_files; i++) {
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