X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/4c40f8344426f43f071312f14cbef9de9838b223..74fc9186bd338b4b69bb19eea19c1f6dabb4b813:/ssh.c diff --git a/ssh.c b/ssh.c index 1a394fba..f9742dc8 100644 --- a/ssh.c +++ b/ssh.c @@ -11,7 +11,11 @@ */ #include "includes.h" -RCSID("$Id$"); +RCSID("$OpenBSD: ssh.c,v 1.56 2000/06/20 01:39:44 markus Exp $"); + +#include +#include +#include #include "xmalloc.h" #include "ssh.h" @@ -21,10 +25,16 @@ RCSID("$Id$"); #include "readconf.h" #include "uidswap.h" +#include "ssh2.h" +#include "compat.h" +#include "channels.h" +#include "key.h" +#include "authfile.h" + #ifdef HAVE___PROGNAME extern char *__progname; #else /* HAVE___PROGNAME */ -const char *__progname = "ssh"; +static const char *__progname = "ssh"; #endif /* HAVE___PROGNAME */ /* Flag indicating whether IPv4 or IPv6. This can be set on the command line. @@ -38,8 +48,13 @@ int IPv4or6 = AF_UNSPEC; /* Flag indicating whether debug mode is on. This can be set on the command line. */ int debug_flag = 0; +/* Flag indicating whether a tty should be allocated */ int tty_flag = 0; +/* don't exec a shell */ +int no_shell_flag = 0; +int no_tty_flag = 0; + /* * Flag indicating that nothing should be read from stdin. This can be set * on the command line. @@ -89,6 +104,9 @@ RSA *host_private_key = NULL; /* Original real UID. */ uid_t original_real_uid; +/* command to be executed */ +Buffer command; + /* Prints a help message to the user. This function never returns. */ void @@ -98,13 +116,16 @@ usage() fprintf(stderr, "Options:\n"); fprintf(stderr, " -l user Log in using this user name.\n"); fprintf(stderr, " -n Redirect input from /dev/null.\n"); + fprintf(stderr, " -A Enable authentication agent forwarding.\n"); fprintf(stderr, " -a Disable authentication agent forwarding.\n"); #ifdef AFS fprintf(stderr, " -k Disable Kerberos ticket and AFS token forwarding.\n"); #endif /* AFS */ + fprintf(stderr, " -X Enable X11 connection forwarding.\n"); fprintf(stderr, " -x Disable X11 connection forwarding.\n"); fprintf(stderr, " -i file Identity for RSA authentication (default: ~/.ssh/identity).\n"); fprintf(stderr, " -t Tty; allocate a tty even if command is given.\n"); + fprintf(stderr, " -T Do not allocate a tty.\n"); fprintf(stderr, " -v Verbose; display verbose debugging messages.\n"); fprintf(stderr, " -V Display version number only.\n"); fprintf(stderr, " -P Don't allocate a privileged port.\n"); @@ -121,9 +142,11 @@ usage() fprintf(stderr, " These cause %s to listen for connections on a port, and\n", av0); fprintf(stderr, " forward them to the other side by connecting to host:port.\n"); fprintf(stderr, " -C Enable compression.\n"); + fprintf(stderr, " -N Do not execute a shell or command.\n"); fprintf(stderr, " -g Allow remote hosts to connect to forwarded ports.\n"); fprintf(stderr, " -4 Use IPv4 only.\n"); fprintf(stderr, " -6 Use IPv6 only.\n"); + fprintf(stderr, " -2 Force protocol version 2.\n"); fprintf(stderr, " -o 'option' Process the option as if it was read from a configuration file.\n"); exit(1); } @@ -166,22 +189,22 @@ rsh_connect(char *host, char *user, Buffer * command) exit(1); } +int ssh_session(void); +int ssh_session2(void); + /* * Main program for the ssh client. */ int main(int ac, char **av) { - int i, opt, optind, type, exit_status, ok, authfd; + int i, opt, optind, exit_status, ok; u_short fwd_port, fwd_host_port; char *optarg, *cp, buf[256]; - Buffer command; - struct winsize ws; struct stat st; struct passwd *pw, pwcopy; - int interactive = 0, dummy; + int dummy; uid_t original_effective_uid; - int plen; /* * Save the original real uid. It will be needed later (uid-swapping @@ -217,10 +240,6 @@ main(int ac, char **av) /* Save our own name. */ av0 = av[0]; -#ifdef SOCKS - SOCKSinit(av0); -#endif /* SOCKS */ - /* Initialize option structure to indicate that no values have been set. */ initialize_options(&options); @@ -241,8 +260,8 @@ main(int ac, char **av) if (host) break; if ((cp = strchr(av[optind], '@'))) { - if(cp == av[optind]) - usage(); + if(cp == av[optind]) + usage(); options.user = av[optind]; *cp = '\0'; host = ++cp; @@ -266,42 +285,40 @@ main(int ac, char **av) optarg = NULL; } switch (opt) { + case '2': + options.protocol = SSH_PROTO_2; + break; case '4': IPv4or6 = AF_INET; break; - case '6': IPv4or6 = AF_INET6; break; - case 'n': stdin_null_flag = 1; break; - case 'f': fork_after_authentication_flag = 1; stdin_null_flag = 1; break; - case 'x': options.forward_x11 = 0; break; - case 'X': options.forward_x11 = 1; break; - case 'g': options.gateway_ports = 1; break; - case 'P': options.use_privileged_port = 0; break; - case 'a': options.forward_agent = 0; break; + case 'A': + options.forward_agent = 1; + break; #ifdef AFS case 'k': options.kerberos_tgt_passing = 0; @@ -320,30 +337,24 @@ main(int ac, char **av) options.identity_files[options.num_identity_files++] = xstrdup(optarg); break; - case 't': tty_flag = 1; break; - case 'v': case 'V': - fprintf(stderr, "SSH Version %s, protocol version %d.%d.\n", - SSH_VERSION, PROTOCOL_MAJOR, PROTOCOL_MINOR); -#ifndef RSAREF - fprintf(stderr, "Compiled with SSL.\n"); -#else - fprintf(stderr, "Compiled with SSL (RSAref version).\n"); -#endif + fprintf(stderr, "SSH Version %s, protocol versions %d.%d/%d.%d.\n", + SSH_VERSION, + PROTOCOL_MAJOR_1, PROTOCOL_MINOR_1, + PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2); + fprintf(stderr, "Compiled with SSL (0x%8.8lx).\n", SSLeay()); if (opt == 'V') exit(0); debug_flag = 1; options.log_level = SYSLOG_LEVEL_DEBUG; break; - case 'q': options.log_level = SYSLOG_LEVEL_QUIET; break; - case 'e': if (optarg[0] == '^' && optarg[2] == 0 && (unsigned char) optarg[1] >= 64 && (unsigned char) optarg[1] < 128) @@ -357,23 +368,26 @@ main(int ac, char **av) exit(1); } break; - case 'c': - options.cipher = cipher_number(optarg); - if (options.cipher == -1) { - fprintf(stderr, "Unknown cipher type '%s'\n", optarg); - exit(1); + if (ciphers_valid(optarg)) { + /* SSH2 only */ + options.ciphers = xstrdup(optarg); + options.cipher = SSH_CIPHER_ILLEGAL; + } else { + /* SSH1 only */ + options.cipher = cipher_number(optarg); + if (options.cipher == -1) { + fprintf(stderr, "Unknown cipher type '%s'\n", optarg); + exit(1); + } } break; - case 'p': options.port = atoi(optarg); break; - case 'l': options.user = optarg; break; - case 'R': if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf, &fwd_host_port) != 3 && @@ -385,7 +399,6 @@ main(int ac, char **av) } add_remote_forward(&options, fwd_port, buf, fwd_host_port); break; - case 'L': if (sscanf(optarg, "%hu/%255[^/]/%hu", &fwd_port, buf, &fwd_host_port) != 3 && @@ -397,18 +410,22 @@ main(int ac, char **av) } add_local_forward(&options, fwd_port, buf, fwd_host_port); break; - case 'C': options.compression = 1; break; - + case 'N': + no_shell_flag = 1; + no_tty_flag = 1; + break; + case 'T': + no_tty_flag = 1; + break; case 'o': dummy = 1; if (process_config_line(&options, host ? host : "", optarg, "command-line", 0, &dummy) != 0) exit(1); break; - default: usage(); } @@ -418,16 +435,11 @@ main(int ac, char **av) if (!host) usage(); - /* check if RSA support exists */ - if (rsa_alive() == 0) { - fprintf(stderr, - "%s: no RSA support in libssl and libcrypto. See ssl(8).\n", - __progname); - exit(1); - } /* Initialize the command to execute on remote host. */ buffer_init(&command); + SSLeay_add_all_algorithms(); + /* * Save the command to execute on the remote host in a buffer. There * is no limit on the length of the command, except by the maximum @@ -460,6 +472,10 @@ main(int ac, char **av) fprintf(stderr, "Pseudo-terminal will not be allocated because stdin is not a terminal.\n"); tty_flag = 0; } + /* force */ + if (no_tty_flag) + tty_flag = 0; + /* Get user data. */ pw = getpwuid(original_real_uid); if (!pw) { @@ -493,6 +509,20 @@ main(int ac, char **av) /* reinit */ log_init(av[0], options.log_level, SYSLOG_FACILITY_USER, 0); + /* check if RSA support exists */ + if ((options.protocol & SSH_PROTO_1) && + rsa_alive() == 0) { + log("%s: no RSA support in libssl and libcrypto. See ssl(8).", + __progname); + log("Disabling protocol version 1"); + options.protocol &= ~ (SSH_PROTO_1|SSH_PROTO_1_PREFERRED); + } + if (! options.protocol & (SSH_PROTO_1|SSH_PROTO_2)) { + fprintf(stderr, "%s: No protocol version available.\n", + __progname); + exit(1); + } + if (options.user == NULL) options.user = xstrdup(pw->pw_name); @@ -505,7 +535,7 @@ main(int ac, char **av) struct addrinfo *ai = NULL; int errgai; memset(&hints, 0, sizeof(hints)); - hints.ai_family = AF_UNSPEC; + hints.ai_family = IPv4or6; hints.ai_flags = AI_CANONNAME; hints.ai_socktype = SOCK_STREAM; errgai = getaddrinfo(host, NULL, &hints, &ai); @@ -559,9 +589,12 @@ main(int ac, char **av) * authentication. This must be done before releasing extra * privileges, because the file is only readable by root. */ - if (ok) { + if (ok && (options.protocol & SSH_PROTO_1)) { + Key k; host_private_key = RSA_new(); - if (load_private_key(HOST_KEY_FILE, "", host_private_key, NULL)) + k.type = KEY_RSA; + k.rsa = host_private_key; + if (load_private_key(HOST_KEY_FILE, "", &k, NULL)) host_private_key_loaded = 1; } /* @@ -607,15 +640,22 @@ main(int ac, char **av) exit(1); } /* Expand ~ in options.identity_files. */ + /* XXX mem-leaks */ for (i = 0; i < options.num_identity_files; i++) options.identity_files[i] = tilde_expand_filename(options.identity_files[i], original_real_uid); - + for (i = 0; i < options.num_identity_files2; i++) + options.identity_files2[i] = + tilde_expand_filename(options.identity_files2[i], original_real_uid); /* Expand ~ in known host file names. */ options.system_hostfile = tilde_expand_filename(options.system_hostfile, - original_real_uid); + original_real_uid); options.user_hostfile = tilde_expand_filename(options.user_hostfile, - original_real_uid); + original_real_uid); + options.system_hostfile2 = tilde_expand_filename(options.system_hostfile2, + original_real_uid); + options.user_hostfile2 = tilde_expand_filename(options.user_hostfile2, + original_real_uid); /* Log into the remote system. This never returns if the login fails. */ ssh_login(host_private_key_loaded, host_private_key, @@ -625,8 +665,61 @@ main(int ac, char **av) if (host_private_key_loaded) RSA_free(host_private_key); /* Destroys contents safely */ - /* Close connection cleanly after attack. */ - cipher_attack_detected = packet_disconnect; + exit_status = compat20 ? ssh_session2() : ssh_session(); + packet_close(); + return exit_status; +} + +void +x11_get_proto(char *proto, int proto_len, char *data, int data_len) +{ + char line[512]; + FILE *f; + int got_data = 0, i; + + if (options.xauth_location) { + /* Try to get Xauthority information for the display. */ + snprintf(line, sizeof line, "%.100s list %.200s 2>/dev/null", + options.xauth_location, getenv("DISPLAY")); + f = popen(line, "r"); + if (f && fgets(line, sizeof(line), f) && + sscanf(line, "%*s %s %s", proto, data) == 2) + got_data = 1; + if (f) + pclose(f); + } + /* + * If we didn't get authentication data, just make up some + * data. The forwarding code will check the validity of the + * response anyway, and substitute this data. The X11 + * server, however, will ignore this fake data and use + * whatever authentication mechanisms it was using otherwise + * for the local connection. + */ + if (!got_data) { + u_int32_t rand = 0; + + strlcpy(proto, "MIT-MAGIC-COOKIE-1", proto_len); + for (i = 0; i < 16; i++) { + if (i % 4 == 0) + rand = arc4random(); + snprintf(data + 2 * i, data_len - 2 * i, "%02x", rand & 0xff); + rand >>= 8; + } + } +} + +int +ssh_session(void) +{ + int type; + int i; + int plen; + int interactive = 0; + int have_tty = 0; + struct winsize ws; + int authfd; + char *cp; /* Enable compression if requested. */ if (options.compression) { @@ -679,65 +772,32 @@ main(int ac, char **av) /* Read response from the server. */ type = packet_read(&plen); - if (type == SSH_SMSG_SUCCESS) + if (type == SSH_SMSG_SUCCESS) { interactive = 1; - else if (type == SSH_SMSG_FAILURE) + have_tty = 1; + } else if (type == SSH_SMSG_FAILURE) log("Warning: Remote host failed or refused to allocate a pseudo tty."); else packet_disconnect("Protocol error waiting for pty request response."); } /* Request X11 forwarding if enabled and DISPLAY is set. */ if (options.forward_x11 && getenv("DISPLAY") != NULL) { - char line[512], proto[512], data[512]; - FILE *f; - int forwarded = 0, got_data = 0, i; - -#ifdef XAUTH_PATH - /* Try to get Xauthority information for the display. */ - snprintf(line, sizeof line, "%.100s list %.200s 2>/dev/null", - XAUTH_PATH, getenv("DISPLAY")); - f = popen(line, "r"); - if (f && fgets(line, sizeof(line), f) && - sscanf(line, "%*s %s %s", proto, data) == 2) - got_data = 1; - if (f) - pclose(f); -#endif /* XAUTH_PATH */ - /* - * If we didn't get authentication data, just make up some - * data. The forwarding code will check the validity of the - * response anyway, and substitute this data. The X11 - * server, however, will ignore this fake data and use - * whatever authentication mechanisms it was using otherwise - * for the local connection. - */ - if (!got_data) { - u_int32_t rand = 0; - - strlcpy(proto, "MIT-MAGIC-COOKIE-1", sizeof proto); - for (i = 0; i < 16; i++) { - if (i % 4 == 0) - rand = arc4random(); - snprintf(data + 2 * i, sizeof data - 2 * i, "%02x", rand & 0xff); - rand >>= 8; - } - } - /* - * Got local authentication reasonable information. Request - * forwarding with authentication spoofing. - */ + char proto[512], data[512]; + /* Get reasonable local authentication information. */ + x11_get_proto(proto, sizeof proto, data, sizeof data); + /* Request forwarding with authentication spoofing. */ debug("Requesting X11 forwarding with authentication spoofing."); - x11_request_forwarding_with_spoofing(proto, data); + x11_request_forwarding_with_spoofing(0, proto, data); /* Read response from the server. */ type = packet_read(&plen); if (type == SSH_SMSG_SUCCESS) { - forwarded = 1; interactive = 1; - } else if (type == SSH_SMSG_FAILURE) + } else if (type == SSH_SMSG_FAILURE) { log("Warning: Remote host denied X11 forwarding."); - else + } else { packet_disconnect("Protocol error waiting for X11 forwarding"); + } } /* Tell the packet module whether this is an interactive session. */ packet_set_interactive(interactive, options.keepalives); @@ -767,7 +827,7 @@ main(int ac, char **av) options.local_forwards[i].host, options.local_forwards[i].host_port); channel_request_local_forwarding(options.local_forwards[i].port, - options.local_forwards[i].host, + options.local_forwards[i].host, options.local_forwards[i].host_port, options.gateway_ports); } @@ -780,11 +840,11 @@ main(int ac, char **av) options.remote_forwards[i].host_port); channel_request_remote_forwarding(options.remote_forwards[i].port, options.remote_forwards[i].host, - options.remote_forwards[i].host_port); + options.remote_forwards[i].host_port); } /* If requested, let ssh continue in the background. */ - if (fork_after_authentication_flag) + if (fork_after_authentication_flag) if (daemon(1, 1) < 0) fatal("daemon() failed: %.200s", strerror(errno)); @@ -809,11 +869,114 @@ main(int ac, char **av) } /* Enter the interactive session. */ - exit_status = client_loop(tty_flag, tty_flag ? options.escape_char : -1); + return client_loop(have_tty, tty_flag ? options.escape_char : -1); +} - /* Close the connection to the remote host. */ - packet_close(); +void +init_local_fwd(void) +{ + int i; + /* Initiate local TCP/IP port forwardings. */ + for (i = 0; i < options.num_local_forwards; i++) { + debug("Connections to local port %d forwarded to remote address %.200s:%d", + options.local_forwards[i].port, + options.local_forwards[i].host, + options.local_forwards[i].host_port); + channel_request_local_forwarding(options.local_forwards[i].port, + options.local_forwards[i].host, + options.local_forwards[i].host_port, + options.gateway_ports); + } +} + +extern void client_set_session_ident(int id); + +void +client_init(int id, void *arg) +{ + int len; + debug("client_init id %d arg %d", id, (int)arg); + + if (no_shell_flag) + goto done; + + if (tty_flag) { + struct winsize ws; + char *cp; + cp = getenv("TERM"); + if (!cp) + cp = ""; + /* Store window size in the packet. */ + if (ioctl(fileno(stdin), TIOCGWINSZ, &ws) < 0) + memset(&ws, 0, sizeof(ws)); + + channel_request_start(id, "pty-req", 0); + packet_put_cstring(cp); + packet_put_int(ws.ws_col); + packet_put_int(ws.ws_row); + packet_put_int(ws.ws_xpixel); + packet_put_int(ws.ws_ypixel); + packet_put_cstring(""); /* XXX: encode terminal modes */ + packet_send(); + /* XXX wait for reply */ + } + if (options.forward_x11 && + getenv("DISPLAY") != NULL) { + char proto[512], data[512]; + /* Get reasonable local authentication information. */ + x11_get_proto(proto, sizeof proto, data, sizeof data); + /* Request forwarding with authentication spoofing. */ + debug("Requesting X11 forwarding with authentication spoofing."); + x11_request_forwarding_with_spoofing(id, proto, data); + /* XXX wait for reply */ + } + + len = buffer_len(&command); + if (len > 0) { + if (len > 900) + len = 900; + debug("Sending command: %.*s", len, buffer_ptr(&command)); + channel_request_start(id, "exec", 0); + packet_put_string(buffer_ptr(&command), len); + packet_send(); + } else { + channel_request(id, "shell", 0); + } + /* channel_callback(id, SSH2_MSG_OPEN_CONFIGMATION, client_init, 0); */ +done: + /* register different callback, etc. XXX */ + client_set_session_ident(id); +} + +int +ssh_session2(void) +{ + int window, packetmax, id; + int in = dup(STDIN_FILENO); + int out = dup(STDOUT_FILENO); + int err = dup(STDERR_FILENO); + + if (in < 0 || out < 0 || err < 0) + fatal("dump in/out/err failed"); + + /* should be pre-session */ + init_local_fwd(); + + window = 32*1024; + if (tty_flag) { + packetmax = window/8; + } else { + window *= 2; + packetmax = window/2; + } + + id = channel_new( + "session", SSH_CHANNEL_OPENING, in, out, err, + window, packetmax, CHAN_EXTENDED_WRITE, xstrdup("client-session")); + + + channel_open(id); + channel_register_callback(id, SSH2_MSG_CHANNEL_OPEN_CONFIRMATION, client_init, (void *)0); - /* Exit with the status returned by the program on the remote side. */ - exit(exit_status); + return client_loop(tty_flag, tty_flag ? options.escape_char : -1); }