16 #define SSH_MSG_DISCONNECT 1
17 #define SSH_SMSG_PUBLIC_KEY 2
18 #define SSH_CMSG_SESSION_KEY 3
19 #define SSH_CMSG_USER 4
20 #define SSH_CMSG_AUTH_PASSWORD 9
21 #define SSH_CMSG_REQUEST_PTY 10
22 #define SSH_CMSG_EXEC_SHELL 12
23 #define SSH_CMSG_STDIN_DATA 16
24 #define SSH_SMSG_STDOUT_DATA 17
25 #define SSH_SMSG_STDERR_DATA 18
26 #define SSH_SMSG_SUCCESS 14
27 #define SSH_SMSG_FAILURE 15
28 #define SSH_SMSG_EXITSTATUS 20
29 #define SSH_MSG_IGNORE 32
30 #define SSH_CMSG_EXIT_CONFIRMATION 33
31 #define SSH_MSG_DEBUG 36
32 #define SSH_CMSG_AUTH_TIS 39
33 #define SSH_SMSG_AUTH_TIS_CHALLENGE 40
34 #define SSH_CMSG_AUTH_TIS_RESPONSE 41
36 #define SSH_AUTH_TIS 5
38 /* Coroutine mechanics for the sillier bits of the code */
39 #define crBegin1 static int crLine = 0;
40 #define crBegin2 switch(crLine) { case 0:;
41 #define crBegin crBegin1; crBegin2;
42 #define crFinish(z) } crLine = 0; return (z)
43 #define crFinishV } crLine = 0; return
46 crLine=__LINE__; return (z); case __LINE__:;\
50 crLine=__LINE__; return; case __LINE__:;\
52 #define crStop(z) do{ crLine = 0; return (z); }while(0)
53 #define crStopV do{ crLine = 0; return; }while(0)
62 static SOCKET s = INVALID_SOCKET;
64 static unsigned char session_key[32];
65 static struct ssh_cipher *cipher = NULL;
67 static char *savedhost;
70 SSH_STATE_BEFORE_SIZE,
74 } ssh_state = SSH_STATE_BEFORE_SIZE;
76 static int size_needed = FALSE;
78 static void s_write (char *buf, int len) {
80 int i = send (s, buf, len, 0);
86 static int s_read (char *buf, int len) {
89 int i = recv (s, buf, len, 0);
91 len -= i, buf += i, ret += i;
98 static void c_write (char *buf, int len) {
100 int new_head = (inbuf_head + 1) & INBUF_MASK;
101 if (new_head != inbuf_reap) {
102 inbuf[inbuf_head] = *buf++;
103 inbuf_head = new_head;
117 static struct Packet pktin = { 0, 0, 0, NULL, 0 };
118 static struct Packet pktout = { 0, 0, 0, NULL, 0 };
120 static void ssh_protocol(unsigned char *in, int inlen, int ispkt);
121 static void ssh_size(void);
123 static void ssh_gotdata(unsigned char *data, int datalen) {
124 static long len, biglen, to_read;
125 static unsigned char *p;
130 for (i = len = 0; i < 4; i++) {
133 len = (len << 8) + *data;
138 if (len == 0x52656d6f) { /* "Remo"te server has closed ... */
139 len = 0x300; /* big enough to carry to end */
147 len -= 5; /* type and CRC */
150 if (pktin.maxlen < biglen) {
151 pktin.maxlen = biglen;
152 pktin.data = (pktin.data == NULL ? malloc(biglen) :
153 realloc(pktin.data, biglen));
155 fatalbox("Out of memory");
158 p = pktin.data, to_read = biglen;
159 while (to_read > 0) {
166 memcpy(p, data, chunk);
174 cipher->decrypt(pktin.data, biglen);
176 pktin.type = pktin.data[pad];
177 pktin.body = pktin.data+pad+1;
179 if (pktin.type == SSH_MSG_DEBUG) {
181 } else if (pktin.type == SSH_MSG_IGNORE) {
184 ssh_protocol(NULL, 0, 1);
189 static void s_wrpkt_start(int type, int len) {
192 len += 5; /* type and CRC */
196 pktout.length = len-5;
197 if (pktout.maxlen < biglen) {
198 pktout.maxlen = biglen;
199 pktout.data = (pktout.data == NULL ? malloc(biglen+4) :
200 realloc(pktout.data, biglen+4));
202 fatalbox("Out of memory");
206 pktout.body = pktout.data+4+pad+1;
209 static void s_wrpkt(void) {
210 int pad, len, biglen, i;
213 len = pktout.length + 5; /* type and CRC */
217 pktout.body[-1] = pktout.type;
218 for (i=0; i<pad; i++)
219 pktout.data[i+4] = random_byte();
220 crc = crc32(pktout.data+4, biglen-4);
222 pktout.data[biglen+0] = (unsigned char) ((crc >> 24) & 0xFF);
223 pktout.data[biglen+1] = (unsigned char) ((crc >> 16) & 0xFF);
224 pktout.data[biglen+2] = (unsigned char) ((crc >> 8) & 0xFF);
225 pktout.data[biglen+3] = (unsigned char) (crc & 0xFF);
227 pktout.data[0] = (len >> 24) & 0xFF;
228 pktout.data[1] = (len >> 16) & 0xFF;
229 pktout.data[2] = (len >> 8) & 0xFF;
230 pktout.data[3] = len & 0xFF;
233 cipher->encrypt(pktout.data+4, biglen);
235 s_write(pktout.data, biglen+4);
238 static int ssh_versioncmp(char *a, char *b) {
240 unsigned long av, bv;
242 av = strtoul(a, &ae, 10);
243 bv = strtoul(b, &be, 10);
244 if (av != bv) return (av < bv ? -1 : +1);
245 if (*ae == '.') ae++;
246 if (*be == '.') be++;
247 av = strtoul(ae, &ae, 10);
248 bv = strtoul(be, &be, 10);
249 if (av != bv) return (av < bv ? -1 : +1);
253 static int do_ssh_init(void) {
257 char vlog[sizeof(vstring)+20];
262 while (s_read(&c, 1) == 1) {
263 if (c == 'S' && i < 2) i++;
264 else if (c == 'S' && i == 2) i = 2;
265 else if (c == 'H' && i == 2) break;
269 if (s_read(&c,1) != 1 || c != 'S') return 0;
270 if (s_read(&c,1) != 1 || c != 'S') return 0;
271 if (s_read(&c,1) != 1 || c != 'H') return 0;
273 strcpy(vstring, "SSH-");
275 if (s_read(&c,1) != 1 || c != '-') return 0;
278 if (s_read(&c,1) != 1)
280 if (vsp < vstring+sizeof(vstring)-1)
286 } else if (i < sizeof(version)-1)
294 sprintf(vlog, "Server version: %s", vstring);
295 vlog[strcspn(vlog, "\r\n")] = '\0';
298 sprintf(vstring, "SSH-%s-PuTTY\n",
299 (ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5"));
300 sprintf(vlog, "We claim version: %s", vstring);
301 vlog[strcspn(vlog, "\r\n")] = '\0';
303 s_write(vstring, strlen(vstring));
307 static void ssh_protocol(unsigned char *in, int inlen, int ispkt) {
309 unsigned char session_id[16];
310 unsigned char *rsabuf, *keystr1, *keystr2;
311 unsigned char cookie[8];
312 struct RSAKey servkey, hostkey;
313 struct MD5Context md5c;
314 static unsigned long supported_ciphers_mask, supported_auths_mask;
317 extern struct ssh_cipher ssh_3des;
318 extern struct ssh_cipher ssh_des;
319 extern struct ssh_cipher ssh_blowfish;
328 if (pktin.type != SSH_SMSG_PUBLIC_KEY)
329 fatalbox("Public key packet not received");
331 logevent("Received public keys");
333 memcpy(cookie, pktin.body, 8);
335 i = makekey(pktin.body+8, &servkey, &keystr1);
337 j = makekey(pktin.body+8+i, &hostkey, &keystr2);
340 * Hash the host key and print the hash in the log box. Just as
341 * a last resort in case the registry's host key checking is
342 * compromised, we'll allow the user some ability to verify
346 MD5Update(&md5c, keystr2, hostkey.bytes);
347 MD5Final(session_id, &md5c);
351 logevent("Host key MD5 is:");
353 for (i = 0; i < 16; i++)
354 sprintf(logmsg+strlen(logmsg), "%02x", session_id[i]);
358 supported_ciphers_mask = ((pktin.body[12+i+j] << 24) |
359 (pktin.body[13+i+j] << 16) |
360 (pktin.body[14+i+j] << 8) |
361 (pktin.body[15+i+j]));
363 supported_auths_mask = ((pktin.body[16+i+j] << 24) |
364 (pktin.body[17+i+j] << 16) |
365 (pktin.body[18+i+j] << 8) |
366 (pktin.body[19+i+j]));
370 MD5Update(&md5c, keystr2, hostkey.bytes);
371 MD5Update(&md5c, keystr1, servkey.bytes);
372 MD5Update(&md5c, pktin.body, 8);
374 MD5Final(session_id, &md5c);
377 session_key[i] = random_byte();
379 len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
381 rsabuf = malloc(len);
383 fatalbox("Out of memory");
385 verify_ssh_host_key(savedhost, &hostkey);
387 for (i=0; i<32; i++) {
388 rsabuf[i] = session_key[i];
390 rsabuf[i] ^= session_id[i];
393 if (hostkey.bytes > servkey.bytes) {
394 rsaencrypt(rsabuf, 32, &servkey);
395 rsaencrypt(rsabuf, servkey.bytes, &hostkey);
397 rsaencrypt(rsabuf, 32, &hostkey);
398 rsaencrypt(rsabuf, hostkey.bytes, &servkey);
401 logevent("Encrypted session key");
403 cipher_type = cfg.cipher == CIPHER_BLOWFISH ? SSH_CIPHER_BLOWFISH :
404 cfg.cipher == CIPHER_DES ? SSH_CIPHER_DES :
406 if ((supported_ciphers_mask & (1 << cipher_type)) == 0) {
407 c_write("Selected cipher not supported, falling back to 3DES\r\n", 53);
408 cipher_type = SSH_CIPHER_3DES;
410 switch (cipher_type) {
411 case SSH_CIPHER_3DES: logevent("Using 3DES encryption"); break;
412 case SSH_CIPHER_DES: logevent("Using single-DES encryption"); break;
413 case SSH_CIPHER_BLOWFISH: logevent("Using Blowfish encryption"); break;
416 s_wrpkt_start(SSH_CMSG_SESSION_KEY, len+15);
417 pktout.body[0] = cipher_type;
418 memcpy(pktout.body+1, cookie, 8);
419 pktout.body[9] = (len*8) >> 8;
420 pktout.body[10] = (len*8) & 0xFF;
421 memcpy(pktout.body+11, rsabuf, len);
422 pktout.body[len+11] = pktout.body[len+12] = 0; /* protocol flags */
423 pktout.body[len+13] = pktout.body[len+14] = 0;
425 logevent("Trying to enable encryption...");
429 cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish :
430 cipher_type == SSH_CIPHER_DES ? &ssh_des :
432 cipher->sesskey(session_key);
434 do { crReturnV; } while (!ispkt);
436 if (pktin.type != SSH_SMSG_SUCCESS)
437 fatalbox("Encryption not successfully enabled");
439 logevent("Successfully started encryption");
443 static char username[100];
446 if (!*cfg.username) {
447 c_write("login as: ", 10);
449 do { crReturnV; } while (ispkt);
450 while (inlen--) switch (c = *in++) {
472 if (c >= ' ' && c <= '~' && pos < 40) {
480 username[strcspn(username, "\n\r")] = '\0';
483 strncpy(username, cfg.username, 99);
485 sprintf(stuff, "Sent username \"%s\".\r\n", username);
486 c_write(stuff, strlen(stuff));
488 s_wrpkt_start(SSH_CMSG_USER, 4+strlen(username));
490 char userlog[20+sizeof(username)];
491 sprintf(userlog, "Sent username \"%s\"", username);
494 pktout.body[0] = pktout.body[1] = pktout.body[2] = 0;
495 pktout.body[3] = strlen(username);
496 memcpy(pktout.body+4, username, strlen(username));
500 do { crReturnV; } while (!ispkt);
502 while (pktin.type == SSH_SMSG_FAILURE) {
503 static char password[100];
506 static int pwpkt_type;
509 * Show password prompt, having first obtained it via a TIS
510 * exchange if we're doing TIS authentication.
512 pwpkt_type = SSH_CMSG_AUTH_PASSWORD;
513 if (pktin.type == SSH_SMSG_FAILURE &&
515 (supported_auths_mask & (1<<SSH_AUTH_TIS))) {
516 pwpkt_type = SSH_CMSG_AUTH_TIS_RESPONSE;
517 logevent("Requested TIS authentication");
518 s_wrpkt_start(SSH_CMSG_AUTH_TIS, 0);
520 do { crReturnV; } while (!ispkt);
521 if (pktin.type != SSH_SMSG_AUTH_TIS_CHALLENGE) {
522 logevent("TIS authentication declined");
523 c_write("TIS authentication refused.\r\n", 29);
525 int challengelen = ((pktin.body[0] << 24) |
526 (pktin.body[1] << 16) |
527 (pktin.body[2] << 8) |
529 logevent("Received TIS challenge");
530 c_write(pktin.body+4, challengelen);
533 if (pwpkt_type == SSH_CMSG_AUTH_PASSWORD)
534 c_write("password: ", 10);
538 do { crReturnV; } while (ispkt);
539 while (inlen--) switch (c = *in++) {
556 if (c >= ' ' && c <= '~' && pos < 40)
562 s_wrpkt_start(pwpkt_type, 4+strlen(password));
563 pktout.body[0] = pktout.body[1] = pktout.body[2] = 0;
564 pktout.body[3] = strlen(password);
565 memcpy(pktout.body+4, password, strlen(password));
567 logevent("Sent password");
568 memset(password, 0, strlen(password));
569 do { crReturnV; } while (!ispkt);
570 if (pktin.type == 15) {
571 c_write("Access denied\r\n", 15);
572 logevent("Authentication refused");
573 } else if (pktin.type != 14) {
574 fatalbox("Strange packet received, type %d", pktin.type);
578 logevent("Authentication successful");
581 i = strlen(cfg.termtype);
582 s_wrpkt_start(SSH_CMSG_REQUEST_PTY, i+5*4+1);
583 pktout.body[0] = (i >> 24) & 0xFF;
584 pktout.body[1] = (i >> 16) & 0xFF;
585 pktout.body[2] = (i >> 8) & 0xFF;
586 pktout.body[3] = i & 0xFF;
587 memcpy(pktout.body+4, cfg.termtype, i);
589 pktout.body[i++] = (rows >> 24) & 0xFF;
590 pktout.body[i++] = (rows >> 16) & 0xFF;
591 pktout.body[i++] = (rows >> 8) & 0xFF;
592 pktout.body[i++] = rows & 0xFF;
593 pktout.body[i++] = (cols >> 24) & 0xFF;
594 pktout.body[i++] = (cols >> 16) & 0xFF;
595 pktout.body[i++] = (cols >> 8) & 0xFF;
596 pktout.body[i++] = cols & 0xFF;
597 memset(pktout.body+i, 0, 9); /* 0 pixwidth, 0 pixheight, 0.b endofopt */
599 ssh_state = SSH_STATE_INTERMED;
600 do { crReturnV; } while (!ispkt);
601 if (pktin.type != SSH_SMSG_SUCCESS && pktin.type != SSH_SMSG_FAILURE) {
602 fatalbox("Protocol confusion");
603 } else if (pktin.type == SSH_SMSG_FAILURE) {
604 c_write("Server refused to allocate pty\r\n", 32);
606 logevent("Allocated pty");
609 s_wrpkt_start(SSH_CMSG_EXEC_SHELL, 0);
611 logevent("Started session");
613 ssh_state = SSH_STATE_SESSION;
620 if (pktin.type == SSH_SMSG_STDOUT_DATA ||
621 pktin.type == SSH_SMSG_STDERR_DATA) {
623 for (i = 0; i < 4; i++)
624 len = (len << 8) + pktin.body[i];
625 c_write(pktin.body+4, len);
626 } else if (pktin.type == SSH_MSG_DISCONNECT) {
627 ssh_state = SSH_STATE_CLOSED;
628 logevent("Received disconnect request");
629 } else if (pktin.type == SSH_SMSG_SUCCESS) {
630 /* may be from EXEC_SHELL on some servers */
631 } else if (pktin.type == SSH_SMSG_FAILURE) {
632 /* may be from EXEC_SHELL on some servers
633 * if no pty is available or in other odd cases. Ignore */
634 } else if (pktin.type == SSH_SMSG_EXITSTATUS) {
635 s_wrpkt_start(SSH_CMSG_EXIT_CONFIRMATION, 0);
638 fatalbox("Strange packet received: type %d", pktin.type);
641 s_wrpkt_start(SSH_CMSG_STDIN_DATA, 4+inlen);
642 pktout.body[0] = (inlen >> 24) & 0xFF;
643 pktout.body[1] = (inlen >> 16) & 0xFF;
644 pktout.body[2] = (inlen >> 8) & 0xFF;
645 pktout.body[3] = inlen & 0xFF;
646 memcpy(pktout.body+4, in, inlen);
655 * Called to set up the connection. Will arrange for WM_NETEVENT
656 * messages to be passed to the specified window, whose window
657 * procedure should then call telnet_msg().
659 * Returns an error message, or NULL on success.
661 * Also places the canonical host name into `realhost'.
663 static char *ssh_init (HWND hwnd, char *host, int port, char **realhost) {
672 savedhost = malloc(1+strlen(host));
674 fatalbox("Out of memory");
675 strcpy(savedhost, host);
687 if ( (a = inet_addr(host)) == (unsigned long) INADDR_NONE) {
688 if ( (h = gethostbyname(host)) == NULL)
689 switch (WSAGetLastError()) {
690 case WSAENETDOWN: return "Network is down";
691 case WSAHOST_NOT_FOUND: case WSANO_DATA:
692 return "Host does not exist";
693 case WSATRY_AGAIN: return "Host not found";
694 default: return "gethostbyname: unknown error";
696 memcpy (&a, h->h_addr, sizeof(a));
697 *realhost = h->h_name;
706 port = 22; /* default ssh port */
711 s = socket(AF_INET, SOCK_STREAM, 0);
712 if (s == INVALID_SOCKET)
713 switch (WSAGetLastError()) {
714 case WSAENETDOWN: return "Network is down";
715 case WSAEAFNOSUPPORT: return "TCP/IP support not present";
716 default: return "socket(): unknown error";
720 * Bind to local address.
722 addr.sin_family = AF_INET;
723 addr.sin_addr.s_addr = htonl(INADDR_ANY);
724 addr.sin_port = htons(0);
725 if (bind (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
726 switch (WSAGetLastError()) {
727 case WSAENETDOWN: return "Network is down";
728 default: return "bind(): unknown error";
732 * Connect to remote address.
734 addr.sin_addr.s_addr = htonl(a);
735 addr.sin_port = htons((short)port);
736 if (connect (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
737 switch (WSAGetLastError()) {
738 case WSAENETDOWN: return "Network is down";
739 case WSAECONNREFUSED: return "Connection refused";
740 case WSAENETUNREACH: return "Network is unreachable";
741 case WSAEHOSTUNREACH: return "No route to host";
742 default: return "connect(): unknown error";
746 send(s, "connect ", 8, 0);
747 send(s, FWhost, strlen(FWhost), 0);
750 sprintf(buf, " %d\n", FWport);
751 send (s, buf, strlen(buf), 0);
756 return "Protocol initialisation error";
758 if (WSAAsyncSelect (s, hwnd, WM_NETEVENT, FD_READ | FD_CLOSE) == SOCKET_ERROR)
759 switch (WSAGetLastError()) {
760 case WSAENETDOWN: return "Network is down";
761 default: return "WSAAsyncSelect(): unknown error";
768 * Process a WM_NETEVENT message. Will return 0 if the connection
769 * has closed, or <0 for a socket error.
771 static int ssh_msg (WPARAM wParam, LPARAM lParam) {
775 if (s == INVALID_SOCKET) /* how the hell did we get here?! */
778 if (WSAGETSELECTERROR(lParam) != 0)
779 return -WSAGETSELECTERROR(lParam);
781 switch (WSAGETSELECTEVENT(lParam)) {
783 ret = recv(s, buf, sizeof(buf), 0);
784 if (ret < 0 && WSAGetLastError() == WSAEWOULDBLOCK)
786 if (ret < 0) /* any _other_ error */
787 return -10000-WSAGetLastError();
790 return 0; /* can't happen, in theory */
792 ssh_gotdata (buf, ret);
796 ssh_state = SSH_STATE_CLOSED;
799 return 1; /* shouldn't happen, but WTF */
803 * Called to send data down the Telnet connection.
805 static void ssh_send (char *buf, int len) {
806 if (s == INVALID_SOCKET)
809 ssh_protocol(buf, len, 0);
813 * Called to set the size of the window from Telnet's POV.
815 static void ssh_size(void) {
817 case SSH_STATE_BEFORE_SIZE:
818 case SSH_STATE_CLOSED:
819 break; /* do nothing */
820 case SSH_STATE_INTERMED:
821 size_needed = TRUE; /* buffer for later */
823 case SSH_STATE_SESSION:
825 s_wrpkt_start(11, 16);
826 pktout.body[0] = (rows >> 24) & 0xFF;
827 pktout.body[1] = (rows >> 16) & 0xFF;
828 pktout.body[2] = (rows >> 8) & 0xFF;
829 pktout.body[3] = rows & 0xFF;
830 pktout.body[4] = (cols >> 24) & 0xFF;
831 pktout.body[5] = (cols >> 16) & 0xFF;
832 pktout.body[6] = (cols >> 8) & 0xFF;
833 pktout.body[7] = cols & 0xFF;
834 memset(pktout.body+8, 0, 8);
841 * (Send Telnet special codes)
843 static void ssh_special (Telnet_Special code) {
847 Backend ssh_backend = {