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;
106 if( inbuf_head == inbuf_reap ) len++; else break;
120 static struct Packet pktin = { 0, 0, 0, NULL, 0 };
121 static struct Packet pktout = { 0, 0, 0, NULL, 0 };
123 static void ssh_protocol(unsigned char *in, int inlen, int ispkt);
124 static void ssh_size(void);
126 static void ssh_gotdata(unsigned char *data, int datalen) {
127 static long len, biglen, to_read;
128 static unsigned char *p;
133 for (i = len = 0; i < 4; i++) {
136 len = (len << 8) + *data;
141 if (len == 0x52656d6f) { /* "Remo"te server has closed ... */
142 len = 0x300; /* big enough to carry to end */
150 len -= 5; /* type and CRC */
153 if (pktin.maxlen < biglen) {
154 pktin.maxlen = biglen;
156 /* Allocate enough buffer space for extra block
157 * for MS CryptEncrypt() */
158 pktin.data = (pktin.data == NULL ? malloc(biglen+8) :
159 realloc(pktin.data, biglen+8));
161 pktin.data = (pktin.data == NULL ? malloc(biglen) :
162 realloc(pktin.data, biglen));
165 fatalbox("Out of memory");
168 p = pktin.data, to_read = biglen;
169 while (to_read > 0) {
176 memcpy(p, data, chunk);
184 cipher->decrypt(pktin.data, biglen);
186 pktin.type = pktin.data[pad];
187 pktin.body = pktin.data+pad+1;
189 if (pktin.type == SSH_MSG_DEBUG) {
191 } else if (pktin.type == SSH_MSG_IGNORE) {
194 ssh_protocol(NULL, 0, 1);
199 static void s_wrpkt_start(int type, int len) {
202 len += 5; /* type and CRC */
206 pktout.length = len-5;
207 if (pktout.maxlen < biglen) {
208 pktout.maxlen = biglen;
210 /* Allocate enough buffer space for extra block
211 * for MS CryptEncrypt() */
212 pktout.data = (pktout.data == NULL ? malloc(biglen+8) :
213 realloc(pktout.data, biglen+8));
215 pktout.data = (pktout.data == NULL ? malloc(biglen+4) :
216 realloc(pktout.data, biglen+4));
219 fatalbox("Out of memory");
223 pktout.body = pktout.data+4+pad+1;
226 static void s_wrpkt(void) {
227 int pad, len, biglen, i;
230 len = pktout.length + 5; /* type and CRC */
234 pktout.body[-1] = pktout.type;
235 for (i=0; i<pad; i++)
236 pktout.data[i+4] = random_byte();
237 crc = crc32(pktout.data+4, biglen-4);
239 pktout.data[biglen+0] = (unsigned char) ((crc >> 24) & 0xFF);
240 pktout.data[biglen+1] = (unsigned char) ((crc >> 16) & 0xFF);
241 pktout.data[biglen+2] = (unsigned char) ((crc >> 8) & 0xFF);
242 pktout.data[biglen+3] = (unsigned char) (crc & 0xFF);
244 pktout.data[0] = (len >> 24) & 0xFF;
245 pktout.data[1] = (len >> 16) & 0xFF;
246 pktout.data[2] = (len >> 8) & 0xFF;
247 pktout.data[3] = len & 0xFF;
250 cipher->encrypt(pktout.data+4, biglen);
252 s_write(pktout.data, biglen+4);
255 static int ssh_versioncmp(char *a, char *b) {
257 unsigned long av, bv;
259 av = strtoul(a, &ae, 10);
260 bv = strtoul(b, &be, 10);
261 if (av != bv) return (av < bv ? -1 : +1);
262 if (*ae == '.') ae++;
263 if (*be == '.') be++;
264 av = strtoul(ae, &ae, 10);
265 bv = strtoul(be, &be, 10);
266 if (av != bv) return (av < bv ? -1 : +1);
270 static int do_ssh_init(void) {
274 char vlog[sizeof(vstring)+20];
279 while (s_read(&c, 1) == 1) {
280 if (c == 'S' && i < 2) i++;
281 else if (c == 'S' && i == 2) i = 2;
282 else if (c == 'H' && i == 2) break;
286 if (s_read(&c,1) != 1 || c != 'S') return 0;
287 if (s_read(&c,1) != 1 || c != 'S') return 0;
288 if (s_read(&c,1) != 1 || c != 'H') return 0;
290 strcpy(vstring, "SSH-");
292 if (s_read(&c,1) != 1 || c != '-') return 0;
295 if (s_read(&c,1) != 1)
297 if (vsp < vstring+sizeof(vstring)-1)
303 } else if (i < sizeof(version)-1)
311 sprintf(vlog, "Server version: %s", vstring);
312 vlog[strcspn(vlog, "\r\n")] = '\0';
315 sprintf(vstring, "SSH-%s-PuTTY\n",
316 (ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5"));
317 sprintf(vlog, "We claim version: %s", vstring);
318 vlog[strcspn(vlog, "\r\n")] = '\0';
320 s_write(vstring, strlen(vstring));
324 static void ssh_protocol(unsigned char *in, int inlen, int ispkt) {
326 unsigned char session_id[16];
327 unsigned char *rsabuf, *keystr1, *keystr2;
328 unsigned char cookie[8];
329 struct RSAKey servkey, hostkey;
330 struct MD5Context md5c;
331 static unsigned long supported_ciphers_mask, supported_auths_mask;
334 extern struct ssh_cipher ssh_3des;
335 extern struct ssh_cipher ssh_des;
336 extern struct ssh_cipher ssh_blowfish;
345 if (pktin.type != SSH_SMSG_PUBLIC_KEY)
346 fatalbox("Public key packet not received");
348 logevent("Received public keys");
350 memcpy(cookie, pktin.body, 8);
352 i = makekey(pktin.body+8, &servkey, &keystr1);
354 j = makekey(pktin.body+8+i, &hostkey, &keystr2);
357 * Hash the host key and print the hash in the log box. Just as
358 * a last resort in case the registry's host key checking is
359 * compromised, we'll allow the user some ability to verify
363 MD5Update(&md5c, keystr2, hostkey.bytes);
364 MD5Final(session_id, &md5c);
368 logevent("Host key MD5 is:");
370 for (i = 0; i < 16; i++)
371 sprintf(logmsg+strlen(logmsg), "%02x", session_id[i]);
375 supported_ciphers_mask = ((pktin.body[12+i+j] << 24) |
376 (pktin.body[13+i+j] << 16) |
377 (pktin.body[14+i+j] << 8) |
378 (pktin.body[15+i+j]));
380 supported_auths_mask = ((pktin.body[16+i+j] << 24) |
381 (pktin.body[17+i+j] << 16) |
382 (pktin.body[18+i+j] << 8) |
383 (pktin.body[19+i+j]));
387 MD5Update(&md5c, keystr2, hostkey.bytes);
388 MD5Update(&md5c, keystr1, servkey.bytes);
389 MD5Update(&md5c, pktin.body, 8);
391 MD5Final(session_id, &md5c);
394 session_key[i] = random_byte();
396 len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
398 rsabuf = malloc(len);
400 fatalbox("Out of memory");
403 * Verify the host key.
407 * First format the key into a string.
409 int len = rsastr_len(&hostkey);
410 char *keystr = malloc(len);
412 fatalbox("Out of memory");
413 rsastr_fmt(keystr, &hostkey);
414 verify_ssh_host_key(savedhost, keystr);
418 for (i=0; i<32; i++) {
419 rsabuf[i] = session_key[i];
421 rsabuf[i] ^= session_id[i];
424 if (hostkey.bytes > servkey.bytes) {
425 rsaencrypt(rsabuf, 32, &servkey);
426 rsaencrypt(rsabuf, servkey.bytes, &hostkey);
428 rsaencrypt(rsabuf, 32, &hostkey);
429 rsaencrypt(rsabuf, hostkey.bytes, &servkey);
432 logevent("Encrypted session key");
434 cipher_type = cfg.cipher == CIPHER_BLOWFISH ? SSH_CIPHER_BLOWFISH :
435 cfg.cipher == CIPHER_DES ? SSH_CIPHER_DES :
437 if ((supported_ciphers_mask & (1 << cipher_type)) == 0) {
438 c_write("Selected cipher not supported, falling back to 3DES\r\n", 53);
439 cipher_type = SSH_CIPHER_3DES;
441 switch (cipher_type) {
442 case SSH_CIPHER_3DES: logevent("Using 3DES encryption"); break;
443 case SSH_CIPHER_DES: logevent("Using single-DES encryption"); break;
444 case SSH_CIPHER_BLOWFISH: logevent("Using Blowfish encryption"); break;
447 s_wrpkt_start(SSH_CMSG_SESSION_KEY, len+15);
448 pktout.body[0] = cipher_type;
449 memcpy(pktout.body+1, cookie, 8);
450 pktout.body[9] = (len*8) >> 8;
451 pktout.body[10] = (len*8) & 0xFF;
452 memcpy(pktout.body+11, rsabuf, len);
453 pktout.body[len+11] = pktout.body[len+12] = 0; /* protocol flags */
454 pktout.body[len+13] = pktout.body[len+14] = 0;
456 logevent("Trying to enable encryption...");
460 cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish :
461 cipher_type == SSH_CIPHER_DES ? &ssh_des :
463 cipher->sesskey(session_key);
465 do { crReturnV; } while (!ispkt);
467 if (pktin.type != SSH_SMSG_SUCCESS)
468 fatalbox("Encryption not successfully enabled");
470 logevent("Successfully started encryption");
474 static char username[100];
477 if (!*cfg.username) {
478 c_write("login as: ", 10);
480 do { crReturnV; } while (ispkt);
481 while (inlen--) switch (c = *in++) {
503 if (((c >= ' ' && c <= '~') ||
504 ((unsigned char)c >= 160)) && pos < 40) {
512 username[strcspn(username, "\n\r")] = '\0';
515 strncpy(username, cfg.username, 99);
517 sprintf(stuff, "Sent username \"%s\".\r\n", username);
518 c_write(stuff, strlen(stuff));
520 s_wrpkt_start(SSH_CMSG_USER, 4+strlen(username));
522 char userlog[20+sizeof(username)];
523 sprintf(userlog, "Sent username \"%s\"", username);
526 pktout.body[0] = pktout.body[1] = pktout.body[2] = 0;
527 pktout.body[3] = strlen(username);
528 memcpy(pktout.body+4, username, strlen(username));
532 do { crReturnV; } while (!ispkt);
534 while (pktin.type == SSH_SMSG_FAILURE) {
535 static char password[100];
538 static int pwpkt_type;
541 * Show password prompt, having first obtained it via a TIS
542 * exchange if we're doing TIS authentication.
544 pwpkt_type = SSH_CMSG_AUTH_PASSWORD;
545 if (pktin.type == SSH_SMSG_FAILURE &&
547 (supported_auths_mask & (1<<SSH_AUTH_TIS))) {
548 pwpkt_type = SSH_CMSG_AUTH_TIS_RESPONSE;
549 logevent("Requested TIS authentication");
550 s_wrpkt_start(SSH_CMSG_AUTH_TIS, 0);
552 do { crReturnV; } while (!ispkt);
553 if (pktin.type != SSH_SMSG_AUTH_TIS_CHALLENGE) {
554 logevent("TIS authentication declined");
555 c_write("TIS authentication refused.\r\n", 29);
557 int challengelen = ((pktin.body[0] << 24) |
558 (pktin.body[1] << 16) |
559 (pktin.body[2] << 8) |
561 logevent("Received TIS challenge");
562 c_write(pktin.body+4, challengelen);
565 if (pwpkt_type == SSH_CMSG_AUTH_PASSWORD)
566 c_write("password: ", 10);
570 do { crReturnV; } while (ispkt);
571 while (inlen--) switch (c = *in++) {
588 if (((c >= ' ' && c <= '~') ||
589 ((unsigned char)c >= 160)) && pos < 40)
595 s_wrpkt_start(pwpkt_type, 4+strlen(password));
596 pktout.body[0] = pktout.body[1] = pktout.body[2] = 0;
597 pktout.body[3] = strlen(password);
598 memcpy(pktout.body+4, password, strlen(password));
600 logevent("Sent password");
601 memset(password, 0, strlen(password));
602 do { crReturnV; } while (!ispkt);
603 if (pktin.type == 15) {
604 c_write("Access denied\r\n", 15);
605 logevent("Authentication refused");
606 } else if (pktin.type != 14) {
607 fatalbox("Strange packet received, type %d", pktin.type);
611 logevent("Authentication successful");
614 i = strlen(cfg.termtype);
615 s_wrpkt_start(SSH_CMSG_REQUEST_PTY, i+5*4+1);
616 pktout.body[0] = (i >> 24) & 0xFF;
617 pktout.body[1] = (i >> 16) & 0xFF;
618 pktout.body[2] = (i >> 8) & 0xFF;
619 pktout.body[3] = i & 0xFF;
620 memcpy(pktout.body+4, cfg.termtype, i);
622 pktout.body[i++] = (rows >> 24) & 0xFF;
623 pktout.body[i++] = (rows >> 16) & 0xFF;
624 pktout.body[i++] = (rows >> 8) & 0xFF;
625 pktout.body[i++] = rows & 0xFF;
626 pktout.body[i++] = (cols >> 24) & 0xFF;
627 pktout.body[i++] = (cols >> 16) & 0xFF;
628 pktout.body[i++] = (cols >> 8) & 0xFF;
629 pktout.body[i++] = cols & 0xFF;
630 memset(pktout.body+i, 0, 9); /* 0 pixwidth, 0 pixheight, 0.b endofopt */
632 ssh_state = SSH_STATE_INTERMED;
633 do { crReturnV; } while (!ispkt);
634 if (pktin.type != SSH_SMSG_SUCCESS && pktin.type != SSH_SMSG_FAILURE) {
635 fatalbox("Protocol confusion");
636 } else if (pktin.type == SSH_SMSG_FAILURE) {
637 c_write("Server refused to allocate pty\r\n", 32);
639 logevent("Allocated pty");
642 s_wrpkt_start(SSH_CMSG_EXEC_SHELL, 0);
644 logevent("Started session");
646 ssh_state = SSH_STATE_SESSION;
653 if (pktin.type == SSH_SMSG_STDOUT_DATA ||
654 pktin.type == SSH_SMSG_STDERR_DATA) {
656 for (i = 0; i < 4; i++)
657 len = (len << 8) + pktin.body[i];
658 c_write(pktin.body+4, len);
659 } else if (pktin.type == SSH_MSG_DISCONNECT) {
660 ssh_state = SSH_STATE_CLOSED;
661 logevent("Received disconnect request");
662 } else if (pktin.type == SSH_SMSG_SUCCESS) {
663 /* may be from EXEC_SHELL on some servers */
664 } else if (pktin.type == SSH_SMSG_FAILURE) {
665 /* may be from EXEC_SHELL on some servers
666 * if no pty is available or in other odd cases. Ignore */
667 } else if (pktin.type == SSH_SMSG_EXITSTATUS) {
668 s_wrpkt_start(SSH_CMSG_EXIT_CONFIRMATION, 0);
671 fatalbox("Strange packet received: type %d", pktin.type);
674 s_wrpkt_start(SSH_CMSG_STDIN_DATA, 4+inlen);
675 pktout.body[0] = (inlen >> 24) & 0xFF;
676 pktout.body[1] = (inlen >> 16) & 0xFF;
677 pktout.body[2] = (inlen >> 8) & 0xFF;
678 pktout.body[3] = inlen & 0xFF;
679 memcpy(pktout.body+4, in, inlen);
688 * Called to set up the connection. Will arrange for WM_NETEVENT
689 * messages to be passed to the specified window, whose window
690 * procedure should then call telnet_msg().
692 * Returns an error message, or NULL on success.
694 * Also places the canonical host name into `realhost'.
696 static char *ssh_init (HWND hwnd, char *host, int port, char **realhost) {
706 if(crypto_startup() == 0)
707 return "Microsoft high encryption pack not installed!";
710 savedhost = malloc(1+strlen(host));
712 fatalbox("Out of memory");
713 strcpy(savedhost, host);
725 if ( (a = inet_addr(host)) == (unsigned long) INADDR_NONE) {
726 if ( (h = gethostbyname(host)) == NULL)
727 switch (WSAGetLastError()) {
728 case WSAENETDOWN: return "Network is down";
729 case WSAHOST_NOT_FOUND: case WSANO_DATA:
730 return "Host does not exist";
731 case WSATRY_AGAIN: return "Host not found";
732 default: return "gethostbyname: unknown error";
734 memcpy (&a, h->h_addr, sizeof(a));
735 *realhost = h->h_name;
744 port = 22; /* default ssh port */
749 s = socket(AF_INET, SOCK_STREAM, 0);
750 if (s == INVALID_SOCKET)
751 switch (WSAGetLastError()) {
752 case WSAENETDOWN: return "Network is down";
753 case WSAEAFNOSUPPORT: return "TCP/IP support not present";
754 default: return "socket(): unknown error";
758 * Bind to local address.
760 addr.sin_family = AF_INET;
761 addr.sin_addr.s_addr = htonl(INADDR_ANY);
762 addr.sin_port = htons(0);
763 if (bind (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
764 switch (WSAGetLastError()) {
765 case WSAENETDOWN: return "Network is down";
766 default: return "bind(): unknown error";
770 * Connect to remote address.
772 addr.sin_addr.s_addr = htonl(a);
773 addr.sin_port = htons((short)port);
774 if (connect (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
775 switch (WSAGetLastError()) {
776 case WSAENETDOWN: return "Network is down";
777 case WSAECONNREFUSED: return "Connection refused";
778 case WSAENETUNREACH: return "Network is unreachable";
779 case WSAEHOSTUNREACH: return "No route to host";
780 default: return "connect(): unknown error";
784 send(s, "connect ", 8, 0);
785 send(s, FWhost, strlen(FWhost), 0);
788 sprintf(buf, " %d\n", FWport);
789 send (s, buf, strlen(buf), 0);
794 return "Protocol initialisation error";
796 if (WSAAsyncSelect (s, hwnd, WM_NETEVENT, FD_READ | FD_CLOSE) == SOCKET_ERROR)
797 switch (WSAGetLastError()) {
798 case WSAENETDOWN: return "Network is down";
799 default: return "WSAAsyncSelect(): unknown error";
806 * Process a WM_NETEVENT message. Will return 0 if the connection
807 * has closed, or <0 for a socket error.
809 static int ssh_msg (WPARAM wParam, LPARAM lParam) {
814 * Because reading less than the whole of the available pending
815 * data can generate an FD_READ event, we need to allow for the
816 * possibility that FD_READ may arrive with FD_CLOSE already in
817 * the queue; so it's possible that we can get here even with s
818 * invalid. If so, we return 1 and don't worry about it.
820 if (s == INVALID_SOCKET)
823 if (WSAGETSELECTERROR(lParam) != 0)
824 return -WSAGETSELECTERROR(lParam);
826 switch (WSAGETSELECTEVENT(lParam)) {
829 ret = recv(s, buf, sizeof(buf), 0);
830 if (ret < 0 && WSAGetLastError() == WSAEWOULDBLOCK)
832 if (ret < 0) /* any _other_ error */
833 return -10000-WSAGetLastError();
838 ssh_gotdata (buf, ret);
841 return 1; /* shouldn't happen, but WTF */
845 * Called to send data down the Telnet connection.
847 static void ssh_send (char *buf, int len) {
848 if (s == INVALID_SOCKET)
851 ssh_protocol(buf, len, 0);
855 * Called to set the size of the window from Telnet's POV.
857 static void ssh_size(void) {
859 case SSH_STATE_BEFORE_SIZE:
860 case SSH_STATE_CLOSED:
861 break; /* do nothing */
862 case SSH_STATE_INTERMED:
863 size_needed = TRUE; /* buffer for later */
865 case SSH_STATE_SESSION:
867 s_wrpkt_start(11, 16);
868 pktout.body[0] = (rows >> 24) & 0xFF;
869 pktout.body[1] = (rows >> 16) & 0xFF;
870 pktout.body[2] = (rows >> 8) & 0xFF;
871 pktout.body[3] = rows & 0xFF;
872 pktout.body[4] = (cols >> 24) & 0xFF;
873 pktout.body[5] = (cols >> 16) & 0xFF;
874 pktout.body[6] = (cols >> 8) & 0xFF;
875 pktout.body[7] = cols & 0xFF;
876 memset(pktout.body+8, 0, 8);
883 * (Send Telnet special codes)
885 static void ssh_special (Telnet_Special code) {
889 Backend ssh_backend = {