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 <= '~' && pos < 40) {
511 username[strcspn(username, "\n\r")] = '\0';
514 strncpy(username, cfg.username, 99);
516 sprintf(stuff, "Sent username \"%s\".\r\n", username);
517 c_write(stuff, strlen(stuff));
519 s_wrpkt_start(SSH_CMSG_USER, 4+strlen(username));
521 char userlog[20+sizeof(username)];
522 sprintf(userlog, "Sent username \"%s\"", username);
525 pktout.body[0] = pktout.body[1] = pktout.body[2] = 0;
526 pktout.body[3] = strlen(username);
527 memcpy(pktout.body+4, username, strlen(username));
531 do { crReturnV; } while (!ispkt);
533 while (pktin.type == SSH_SMSG_FAILURE) {
534 static char password[100];
537 static int pwpkt_type;
540 * Show password prompt, having first obtained it via a TIS
541 * exchange if we're doing TIS authentication.
543 pwpkt_type = SSH_CMSG_AUTH_PASSWORD;
544 if (pktin.type == SSH_SMSG_FAILURE &&
546 (supported_auths_mask & (1<<SSH_AUTH_TIS))) {
547 pwpkt_type = SSH_CMSG_AUTH_TIS_RESPONSE;
548 logevent("Requested TIS authentication");
549 s_wrpkt_start(SSH_CMSG_AUTH_TIS, 0);
551 do { crReturnV; } while (!ispkt);
552 if (pktin.type != SSH_SMSG_AUTH_TIS_CHALLENGE) {
553 logevent("TIS authentication declined");
554 c_write("TIS authentication refused.\r\n", 29);
556 int challengelen = ((pktin.body[0] << 24) |
557 (pktin.body[1] << 16) |
558 (pktin.body[2] << 8) |
560 logevent("Received TIS challenge");
561 c_write(pktin.body+4, challengelen);
564 if (pwpkt_type == SSH_CMSG_AUTH_PASSWORD)
565 c_write("password: ", 10);
569 do { crReturnV; } while (ispkt);
570 while (inlen--) switch (c = *in++) {
587 if (c >= ' ' && c <= '~' && pos < 40)
593 s_wrpkt_start(pwpkt_type, 4+strlen(password));
594 pktout.body[0] = pktout.body[1] = pktout.body[2] = 0;
595 pktout.body[3] = strlen(password);
596 memcpy(pktout.body+4, password, strlen(password));
598 logevent("Sent password");
599 memset(password, 0, strlen(password));
600 do { crReturnV; } while (!ispkt);
601 if (pktin.type == 15) {
602 c_write("Access denied\r\n", 15);
603 logevent("Authentication refused");
604 } else if (pktin.type != 14) {
605 fatalbox("Strange packet received, type %d", pktin.type);
609 logevent("Authentication successful");
612 i = strlen(cfg.termtype);
613 s_wrpkt_start(SSH_CMSG_REQUEST_PTY, i+5*4+1);
614 pktout.body[0] = (i >> 24) & 0xFF;
615 pktout.body[1] = (i >> 16) & 0xFF;
616 pktout.body[2] = (i >> 8) & 0xFF;
617 pktout.body[3] = i & 0xFF;
618 memcpy(pktout.body+4, cfg.termtype, i);
620 pktout.body[i++] = (rows >> 24) & 0xFF;
621 pktout.body[i++] = (rows >> 16) & 0xFF;
622 pktout.body[i++] = (rows >> 8) & 0xFF;
623 pktout.body[i++] = rows & 0xFF;
624 pktout.body[i++] = (cols >> 24) & 0xFF;
625 pktout.body[i++] = (cols >> 16) & 0xFF;
626 pktout.body[i++] = (cols >> 8) & 0xFF;
627 pktout.body[i++] = cols & 0xFF;
628 memset(pktout.body+i, 0, 9); /* 0 pixwidth, 0 pixheight, 0.b endofopt */
630 ssh_state = SSH_STATE_INTERMED;
631 do { crReturnV; } while (!ispkt);
632 if (pktin.type != SSH_SMSG_SUCCESS && pktin.type != SSH_SMSG_FAILURE) {
633 fatalbox("Protocol confusion");
634 } else if (pktin.type == SSH_SMSG_FAILURE) {
635 c_write("Server refused to allocate pty\r\n", 32);
637 logevent("Allocated pty");
640 s_wrpkt_start(SSH_CMSG_EXEC_SHELL, 0);
642 logevent("Started session");
644 ssh_state = SSH_STATE_SESSION;
651 if (pktin.type == SSH_SMSG_STDOUT_DATA ||
652 pktin.type == SSH_SMSG_STDERR_DATA) {
654 for (i = 0; i < 4; i++)
655 len = (len << 8) + pktin.body[i];
656 c_write(pktin.body+4, len);
657 } else if (pktin.type == SSH_MSG_DISCONNECT) {
658 ssh_state = SSH_STATE_CLOSED;
659 logevent("Received disconnect request");
660 } else if (pktin.type == SSH_SMSG_SUCCESS) {
661 /* may be from EXEC_SHELL on some servers */
662 } else if (pktin.type == SSH_SMSG_FAILURE) {
663 /* may be from EXEC_SHELL on some servers
664 * if no pty is available or in other odd cases. Ignore */
665 } else if (pktin.type == SSH_SMSG_EXITSTATUS) {
666 s_wrpkt_start(SSH_CMSG_EXIT_CONFIRMATION, 0);
669 fatalbox("Strange packet received: type %d", pktin.type);
672 s_wrpkt_start(SSH_CMSG_STDIN_DATA, 4+inlen);
673 pktout.body[0] = (inlen >> 24) & 0xFF;
674 pktout.body[1] = (inlen >> 16) & 0xFF;
675 pktout.body[2] = (inlen >> 8) & 0xFF;
676 pktout.body[3] = inlen & 0xFF;
677 memcpy(pktout.body+4, in, inlen);
686 * Called to set up the connection. Will arrange for WM_NETEVENT
687 * messages to be passed to the specified window, whose window
688 * procedure should then call telnet_msg().
690 * Returns an error message, or NULL on success.
692 * Also places the canonical host name into `realhost'.
694 static char *ssh_init (HWND hwnd, char *host, int port, char **realhost) {
704 if(crypto_startup() == 0)
705 return "Microsoft high encryption pack not installed!";
708 savedhost = malloc(1+strlen(host));
710 fatalbox("Out of memory");
711 strcpy(savedhost, host);
723 if ( (a = inet_addr(host)) == (unsigned long) INADDR_NONE) {
724 if ( (h = gethostbyname(host)) == NULL)
725 switch (WSAGetLastError()) {
726 case WSAENETDOWN: return "Network is down";
727 case WSAHOST_NOT_FOUND: case WSANO_DATA:
728 return "Host does not exist";
729 case WSATRY_AGAIN: return "Host not found";
730 default: return "gethostbyname: unknown error";
732 memcpy (&a, h->h_addr, sizeof(a));
733 *realhost = h->h_name;
742 port = 22; /* default ssh port */
747 s = socket(AF_INET, SOCK_STREAM, 0);
748 if (s == INVALID_SOCKET)
749 switch (WSAGetLastError()) {
750 case WSAENETDOWN: return "Network is down";
751 case WSAEAFNOSUPPORT: return "TCP/IP support not present";
752 default: return "socket(): unknown error";
756 * Bind to local address.
758 addr.sin_family = AF_INET;
759 addr.sin_addr.s_addr = htonl(INADDR_ANY);
760 addr.sin_port = htons(0);
761 if (bind (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
762 switch (WSAGetLastError()) {
763 case WSAENETDOWN: return "Network is down";
764 default: return "bind(): unknown error";
768 * Connect to remote address.
770 addr.sin_addr.s_addr = htonl(a);
771 addr.sin_port = htons((short)port);
772 if (connect (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
773 switch (WSAGetLastError()) {
774 case WSAENETDOWN: return "Network is down";
775 case WSAECONNREFUSED: return "Connection refused";
776 case WSAENETUNREACH: return "Network is unreachable";
777 case WSAEHOSTUNREACH: return "No route to host";
778 default: return "connect(): unknown error";
782 send(s, "connect ", 8, 0);
783 send(s, FWhost, strlen(FWhost), 0);
786 sprintf(buf, " %d\n", FWport);
787 send (s, buf, strlen(buf), 0);
792 return "Protocol initialisation error";
794 if (WSAAsyncSelect (s, hwnd, WM_NETEVENT, FD_READ | FD_CLOSE) == SOCKET_ERROR)
795 switch (WSAGetLastError()) {
796 case WSAENETDOWN: return "Network is down";
797 default: return "WSAAsyncSelect(): unknown error";
804 * Process a WM_NETEVENT message. Will return 0 if the connection
805 * has closed, or <0 for a socket error.
807 static int ssh_msg (WPARAM wParam, LPARAM lParam) {
812 * Because reading less than the whole of the available pending
813 * data can generate an FD_READ event, we need to allow for the
814 * possibility that FD_READ may arrive with FD_CLOSE already in
815 * the queue; so it's possible that we can get here even with s
816 * invalid. If so, we return 1 and don't worry about it.
818 if (s == INVALID_SOCKET)
821 if (WSAGETSELECTERROR(lParam) != 0)
822 return -WSAGETSELECTERROR(lParam);
824 switch (WSAGETSELECTEVENT(lParam)) {
827 ret = recv(s, buf, sizeof(buf), 0);
828 if (ret < 0 && WSAGetLastError() == WSAEWOULDBLOCK)
830 if (ret < 0) /* any _other_ error */
831 return -10000-WSAGetLastError();
836 ssh_gotdata (buf, ret);
839 return 1; /* shouldn't happen, but WTF */
843 * Called to send data down the Telnet connection.
845 static void ssh_send (char *buf, int len) {
846 if (s == INVALID_SOCKET)
849 ssh_protocol(buf, len, 0);
853 * Called to set the size of the window from Telnet's POV.
855 static void ssh_size(void) {
857 case SSH_STATE_BEFORE_SIZE:
858 case SSH_STATE_CLOSED:
859 break; /* do nothing */
860 case SSH_STATE_INTERMED:
861 size_needed = TRUE; /* buffer for later */
863 case SSH_STATE_SESSION:
865 s_wrpkt_start(11, 16);
866 pktout.body[0] = (rows >> 24) & 0xFF;
867 pktout.body[1] = (rows >> 16) & 0xFF;
868 pktout.body[2] = (rows >> 8) & 0xFF;
869 pktout.body[3] = rows & 0xFF;
870 pktout.body[4] = (cols >> 24) & 0xFF;
871 pktout.body[5] = (cols >> 16) & 0xFF;
872 pktout.body[6] = (cols >> 8) & 0xFF;
873 pktout.body[7] = cols & 0xFF;
874 memset(pktout.body+8, 0, 8);
881 * (Send Telnet special codes)
883 static void ssh_special (Telnet_Special code) {
887 Backend ssh_backend = {