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;
130 static unsigned long realcrc, gotcrc;
134 for (i = len = 0; i < 4; i++) {
137 len = (len << 8) + *data;
142 if (len == 0x52656d6f) { /* "Remo"te server has closed ... */
143 len = 0x300; /* big enough to carry to end */
151 len -= 5; /* type and CRC */
154 if (pktin.maxlen < biglen) {
155 pktin.maxlen = biglen;
157 /* Allocate enough buffer space for extra block
158 * for MS CryptEncrypt() */
159 pktin.data = (pktin.data == NULL ? malloc(biglen+8) :
160 realloc(pktin.data, biglen+8));
162 pktin.data = (pktin.data == NULL ? malloc(biglen) :
163 realloc(pktin.data, biglen));
166 fatalbox("Out of memory");
169 p = pktin.data, to_read = biglen;
170 while (to_read > 0) {
177 memcpy(p, data, chunk);
185 cipher->decrypt(pktin.data, biglen);
187 pktin.type = pktin.data[pad];
188 pktin.body = pktin.data+pad+1;
190 realcrc = crc32(pktin.data, biglen-4);
191 gotcrc = (pktin.data[biglen-4] << 24);
192 gotcrc |= (pktin.data[biglen-3] << 16);
193 gotcrc |= (pktin.data[biglen-2] << 8);
194 gotcrc |= (pktin.data[biglen-1] << 0);
195 if (gotcrc != realcrc) {
196 fatalbox("Incorrect CRC received on packet");
199 if (pktin.type == SSH_MSG_DEBUG) {
201 } else if (pktin.type == SSH_MSG_IGNORE) {
204 ssh_protocol(NULL, 0, 1);
209 static void s_wrpkt_start(int type, int len) {
212 len += 5; /* type and CRC */
216 pktout.length = len-5;
217 if (pktout.maxlen < biglen) {
218 pktout.maxlen = biglen;
220 /* Allocate enough buffer space for extra block
221 * for MS CryptEncrypt() */
222 pktout.data = (pktout.data == NULL ? malloc(biglen+8) :
223 realloc(pktout.data, biglen+8));
225 pktout.data = (pktout.data == NULL ? malloc(biglen+4) :
226 realloc(pktout.data, biglen+4));
229 fatalbox("Out of memory");
233 pktout.body = pktout.data+4+pad+1;
236 static void s_wrpkt(void) {
237 int pad, len, biglen, i;
240 len = pktout.length + 5; /* type and CRC */
244 pktout.body[-1] = pktout.type;
245 for (i=0; i<pad; i++)
246 pktout.data[i+4] = random_byte();
247 crc = crc32(pktout.data+4, biglen-4);
249 pktout.data[biglen+0] = (unsigned char) ((crc >> 24) & 0xFF);
250 pktout.data[biglen+1] = (unsigned char) ((crc >> 16) & 0xFF);
251 pktout.data[biglen+2] = (unsigned char) ((crc >> 8) & 0xFF);
252 pktout.data[biglen+3] = (unsigned char) (crc & 0xFF);
254 pktout.data[0] = (len >> 24) & 0xFF;
255 pktout.data[1] = (len >> 16) & 0xFF;
256 pktout.data[2] = (len >> 8) & 0xFF;
257 pktout.data[3] = len & 0xFF;
260 cipher->encrypt(pktout.data+4, biglen);
262 s_write(pktout.data, biglen+4);
265 static int ssh_versioncmp(char *a, char *b) {
267 unsigned long av, bv;
269 av = strtoul(a, &ae, 10);
270 bv = strtoul(b, &be, 10);
271 if (av != bv) return (av < bv ? -1 : +1);
272 if (*ae == '.') ae++;
273 if (*be == '.') be++;
274 av = strtoul(ae, &ae, 10);
275 bv = strtoul(be, &be, 10);
276 if (av != bv) return (av < bv ? -1 : +1);
280 static int do_ssh_init(void) {
284 char vlog[sizeof(vstring)+20];
289 while (s_read(&c, 1) == 1) {
290 if (c == 'S' && i < 2) i++;
291 else if (c == 'S' && i == 2) i = 2;
292 else if (c == 'H' && i == 2) break;
296 if (s_read(&c,1) != 1 || c != 'S') return 0;
297 if (s_read(&c,1) != 1 || c != 'S') return 0;
298 if (s_read(&c,1) != 1 || c != 'H') return 0;
300 strcpy(vstring, "SSH-");
302 if (s_read(&c,1) != 1 || c != '-') return 0;
305 if (s_read(&c,1) != 1)
307 if (vsp < vstring+sizeof(vstring)-1)
313 } else if (i < sizeof(version)-1)
321 sprintf(vlog, "Server version: %s", vstring);
322 vlog[strcspn(vlog, "\r\n")] = '\0';
325 sprintf(vstring, "SSH-%s-PuTTY\n",
326 (ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5"));
327 sprintf(vlog, "We claim version: %s", vstring);
328 vlog[strcspn(vlog, "\r\n")] = '\0';
330 s_write(vstring, strlen(vstring));
334 static void ssh_protocol(unsigned char *in, int inlen, int ispkt) {
336 unsigned char session_id[16];
337 unsigned char *rsabuf, *keystr1, *keystr2;
338 unsigned char cookie[8];
339 struct RSAKey servkey, hostkey;
340 struct MD5Context md5c;
341 static unsigned long supported_ciphers_mask, supported_auths_mask;
344 extern struct ssh_cipher ssh_3des;
345 extern struct ssh_cipher ssh_des;
346 extern struct ssh_cipher ssh_blowfish;
355 if (pktin.type != SSH_SMSG_PUBLIC_KEY)
356 fatalbox("Public key packet not received");
358 logevent("Received public keys");
360 memcpy(cookie, pktin.body, 8);
362 i = makekey(pktin.body+8, &servkey, &keystr1);
364 j = makekey(pktin.body+8+i, &hostkey, &keystr2);
367 * Hash the host key and print the hash in the log box. Just as
368 * a last resort in case the registry's host key checking is
369 * compromised, we'll allow the user some ability to verify
373 MD5Update(&md5c, keystr2, hostkey.bytes);
374 MD5Final(session_id, &md5c);
378 logevent("Host key MD5 is:");
380 for (i = 0; i < 16; i++)
381 sprintf(logmsg+strlen(logmsg), "%02x", session_id[i]);
385 supported_ciphers_mask = ((pktin.body[12+i+j] << 24) |
386 (pktin.body[13+i+j] << 16) |
387 (pktin.body[14+i+j] << 8) |
388 (pktin.body[15+i+j]));
390 supported_auths_mask = ((pktin.body[16+i+j] << 24) |
391 (pktin.body[17+i+j] << 16) |
392 (pktin.body[18+i+j] << 8) |
393 (pktin.body[19+i+j]));
397 MD5Update(&md5c, keystr2, hostkey.bytes);
398 MD5Update(&md5c, keystr1, servkey.bytes);
399 MD5Update(&md5c, pktin.body, 8);
401 MD5Final(session_id, &md5c);
404 session_key[i] = random_byte();
406 len = (hostkey.bytes > servkey.bytes ? hostkey.bytes : servkey.bytes);
408 rsabuf = malloc(len);
410 fatalbox("Out of memory");
413 * Verify the host key.
417 * First format the key into a string.
419 int len = rsastr_len(&hostkey);
420 char *keystr = malloc(len);
422 fatalbox("Out of memory");
423 rsastr_fmt(keystr, &hostkey);
424 verify_ssh_host_key(savedhost, keystr);
428 for (i=0; i<32; i++) {
429 rsabuf[i] = session_key[i];
431 rsabuf[i] ^= session_id[i];
434 if (hostkey.bytes > servkey.bytes) {
435 rsaencrypt(rsabuf, 32, &servkey);
436 rsaencrypt(rsabuf, servkey.bytes, &hostkey);
438 rsaencrypt(rsabuf, 32, &hostkey);
439 rsaencrypt(rsabuf, hostkey.bytes, &servkey);
442 logevent("Encrypted session key");
444 cipher_type = cfg.cipher == CIPHER_BLOWFISH ? SSH_CIPHER_BLOWFISH :
445 cfg.cipher == CIPHER_DES ? SSH_CIPHER_DES :
447 if ((supported_ciphers_mask & (1 << cipher_type)) == 0) {
448 c_write("Selected cipher not supported, falling back to 3DES\r\n", 53);
449 cipher_type = SSH_CIPHER_3DES;
451 switch (cipher_type) {
452 case SSH_CIPHER_3DES: logevent("Using 3DES encryption"); break;
453 case SSH_CIPHER_DES: logevent("Using single-DES encryption"); break;
454 case SSH_CIPHER_BLOWFISH: logevent("Using Blowfish encryption"); break;
457 s_wrpkt_start(SSH_CMSG_SESSION_KEY, len+15);
458 pktout.body[0] = cipher_type;
459 memcpy(pktout.body+1, cookie, 8);
460 pktout.body[9] = (len*8) >> 8;
461 pktout.body[10] = (len*8) & 0xFF;
462 memcpy(pktout.body+11, rsabuf, len);
463 pktout.body[len+11] = pktout.body[len+12] = 0; /* protocol flags */
464 pktout.body[len+13] = pktout.body[len+14] = 0;
466 logevent("Trying to enable encryption...");
470 cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish :
471 cipher_type == SSH_CIPHER_DES ? &ssh_des :
473 cipher->sesskey(session_key);
475 do { crReturnV; } while (!ispkt);
477 if (pktin.type != SSH_SMSG_SUCCESS)
478 fatalbox("Encryption not successfully enabled");
480 logevent("Successfully started encryption");
484 static char username[100];
487 if (!*cfg.username) {
488 c_write("login as: ", 10);
490 do { crReturnV; } while (ispkt);
491 while (inlen--) switch (c = *in++) {
513 if (((c >= ' ' && c <= '~') ||
514 ((unsigned char)c >= 160)) && pos < 40) {
522 username[strcspn(username, "\n\r")] = '\0';
525 strncpy(username, cfg.username, 99);
527 sprintf(stuff, "Sent username \"%s\".\r\n", username);
528 c_write(stuff, strlen(stuff));
530 s_wrpkt_start(SSH_CMSG_USER, 4+strlen(username));
532 char userlog[20+sizeof(username)];
533 sprintf(userlog, "Sent username \"%s\"", username);
536 pktout.body[0] = pktout.body[1] = pktout.body[2] = 0;
537 pktout.body[3] = strlen(username);
538 memcpy(pktout.body+4, username, strlen(username));
542 do { crReturnV; } while (!ispkt);
544 while (pktin.type == SSH_SMSG_FAILURE) {
545 static char password[100];
548 static int pwpkt_type;
551 * Show password prompt, having first obtained it via a TIS
552 * exchange if we're doing TIS authentication.
554 pwpkt_type = SSH_CMSG_AUTH_PASSWORD;
555 if (pktin.type == SSH_SMSG_FAILURE &&
557 (supported_auths_mask & (1<<SSH_AUTH_TIS))) {
558 pwpkt_type = SSH_CMSG_AUTH_TIS_RESPONSE;
559 logevent("Requested TIS authentication");
560 s_wrpkt_start(SSH_CMSG_AUTH_TIS, 0);
562 do { crReturnV; } while (!ispkt);
563 if (pktin.type != SSH_SMSG_AUTH_TIS_CHALLENGE) {
564 logevent("TIS authentication declined");
565 c_write("TIS authentication refused.\r\n", 29);
567 int challengelen = ((pktin.body[0] << 24) |
568 (pktin.body[1] << 16) |
569 (pktin.body[2] << 8) |
571 logevent("Received TIS challenge");
572 c_write(pktin.body+4, challengelen);
575 if (pwpkt_type == SSH_CMSG_AUTH_PASSWORD)
576 c_write("password: ", 10);
580 do { crReturnV; } while (ispkt);
581 while (inlen--) switch (c = *in++) {
598 if (((c >= ' ' && c <= '~') ||
599 ((unsigned char)c >= 160)) && pos < 40)
605 s_wrpkt_start(pwpkt_type, 4+strlen(password));
606 pktout.body[0] = pktout.body[1] = pktout.body[2] = 0;
607 pktout.body[3] = strlen(password);
608 memcpy(pktout.body+4, password, strlen(password));
610 logevent("Sent password");
611 memset(password, 0, strlen(password));
612 do { crReturnV; } while (!ispkt);
613 if (pktin.type == 15) {
614 c_write("Access denied\r\n", 15);
615 logevent("Authentication refused");
616 } else if (pktin.type != 14) {
617 fatalbox("Strange packet received, type %d", pktin.type);
621 logevent("Authentication successful");
624 i = strlen(cfg.termtype);
625 s_wrpkt_start(SSH_CMSG_REQUEST_PTY, i+5*4+1);
626 pktout.body[0] = (i >> 24) & 0xFF;
627 pktout.body[1] = (i >> 16) & 0xFF;
628 pktout.body[2] = (i >> 8) & 0xFF;
629 pktout.body[3] = i & 0xFF;
630 memcpy(pktout.body+4, cfg.termtype, i);
632 pktout.body[i++] = (rows >> 24) & 0xFF;
633 pktout.body[i++] = (rows >> 16) & 0xFF;
634 pktout.body[i++] = (rows >> 8) & 0xFF;
635 pktout.body[i++] = rows & 0xFF;
636 pktout.body[i++] = (cols >> 24) & 0xFF;
637 pktout.body[i++] = (cols >> 16) & 0xFF;
638 pktout.body[i++] = (cols >> 8) & 0xFF;
639 pktout.body[i++] = cols & 0xFF;
640 memset(pktout.body+i, 0, 9); /* 0 pixwidth, 0 pixheight, 0.b endofopt */
642 ssh_state = SSH_STATE_INTERMED;
643 do { crReturnV; } while (!ispkt);
644 if (pktin.type != SSH_SMSG_SUCCESS && pktin.type != SSH_SMSG_FAILURE) {
645 fatalbox("Protocol confusion");
646 } else if (pktin.type == SSH_SMSG_FAILURE) {
647 c_write("Server refused to allocate pty\r\n", 32);
649 logevent("Allocated pty");
652 s_wrpkt_start(SSH_CMSG_EXEC_SHELL, 0);
654 logevent("Started session");
656 ssh_state = SSH_STATE_SESSION;
663 if (pktin.type == SSH_SMSG_STDOUT_DATA ||
664 pktin.type == SSH_SMSG_STDERR_DATA) {
666 for (i = 0; i < 4; i++)
667 len = (len << 8) + pktin.body[i];
668 if (len+4 != pktin.length) {
669 logevent("Received data packet with bogus string length"
672 c_write(pktin.body+4, len);
673 } else if (pktin.type == SSH_MSG_DISCONNECT) {
674 ssh_state = SSH_STATE_CLOSED;
675 logevent("Received disconnect request");
676 } else if (pktin.type == SSH_SMSG_SUCCESS) {
677 /* may be from EXEC_SHELL on some servers */
678 } else if (pktin.type == SSH_SMSG_FAILURE) {
679 /* may be from EXEC_SHELL on some servers
680 * if no pty is available or in other odd cases. Ignore */
681 } else if (pktin.type == SSH_SMSG_EXITSTATUS) {
682 s_wrpkt_start(SSH_CMSG_EXIT_CONFIRMATION, 0);
685 fatalbox("Strange packet received: type %d", pktin.type);
688 s_wrpkt_start(SSH_CMSG_STDIN_DATA, 4+inlen);
689 pktout.body[0] = (inlen >> 24) & 0xFF;
690 pktout.body[1] = (inlen >> 16) & 0xFF;
691 pktout.body[2] = (inlen >> 8) & 0xFF;
692 pktout.body[3] = inlen & 0xFF;
693 memcpy(pktout.body+4, in, inlen);
702 * Called to set up the connection. Will arrange for WM_NETEVENT
703 * messages to be passed to the specified window, whose window
704 * procedure should then call telnet_msg().
706 * Returns an error message, or NULL on success.
708 * Also places the canonical host name into `realhost'.
710 static char *ssh_init (HWND hwnd, char *host, int port, char **realhost) {
720 if(crypto_startup() == 0)
721 return "Microsoft high encryption pack not installed!";
724 savedhost = malloc(1+strlen(host));
726 fatalbox("Out of memory");
727 strcpy(savedhost, host);
739 if ( (a = inet_addr(host)) == (unsigned long) INADDR_NONE) {
740 if ( (h = gethostbyname(host)) == NULL)
741 switch (WSAGetLastError()) {
742 case WSAENETDOWN: return "Network is down";
743 case WSAHOST_NOT_FOUND: case WSANO_DATA:
744 return "Host does not exist";
745 case WSATRY_AGAIN: return "Host not found";
746 default: return "gethostbyname: unknown error";
748 memcpy (&a, h->h_addr, sizeof(a));
749 *realhost = h->h_name;
758 port = 22; /* default ssh port */
763 s = socket(AF_INET, SOCK_STREAM, 0);
764 if (s == INVALID_SOCKET)
765 switch (WSAGetLastError()) {
766 case WSAENETDOWN: return "Network is down";
767 case WSAEAFNOSUPPORT: return "TCP/IP support not present";
768 default: return "socket(): unknown error";
772 * Bind to local address.
774 addr.sin_family = AF_INET;
775 addr.sin_addr.s_addr = htonl(INADDR_ANY);
776 addr.sin_port = htons(0);
777 if (bind (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
778 switch (WSAGetLastError()) {
779 case WSAENETDOWN: return "Network is down";
780 default: return "bind(): unknown error";
784 * Connect to remote address.
786 addr.sin_addr.s_addr = htonl(a);
787 addr.sin_port = htons((short)port);
788 if (connect (s, (struct sockaddr *)&addr, sizeof(addr)) == SOCKET_ERROR)
789 switch (WSAGetLastError()) {
790 case WSAENETDOWN: return "Network is down";
791 case WSAECONNREFUSED: return "Connection refused";
792 case WSAENETUNREACH: return "Network is unreachable";
793 case WSAEHOSTUNREACH: return "No route to host";
794 default: return "connect(): unknown error";
798 send(s, "connect ", 8, 0);
799 send(s, FWhost, strlen(FWhost), 0);
802 sprintf(buf, " %d\n", FWport);
803 send (s, buf, strlen(buf), 0);
808 return "Protocol initialisation error";
810 if (WSAAsyncSelect (s, hwnd, WM_NETEVENT, FD_READ | FD_CLOSE) == SOCKET_ERROR)
811 switch (WSAGetLastError()) {
812 case WSAENETDOWN: return "Network is down";
813 default: return "WSAAsyncSelect(): unknown error";
820 * Process a WM_NETEVENT message. Will return 0 if the connection
821 * has closed, or <0 for a socket error.
823 static int ssh_msg (WPARAM wParam, LPARAM lParam) {
828 * Because reading less than the whole of the available pending
829 * data can generate an FD_READ event, we need to allow for the
830 * possibility that FD_READ may arrive with FD_CLOSE already in
831 * the queue; so it's possible that we can get here even with s
832 * invalid. If so, we return 1 and don't worry about it.
834 if (s == INVALID_SOCKET)
837 if (WSAGETSELECTERROR(lParam) != 0)
838 return -WSAGETSELECTERROR(lParam);
840 switch (WSAGETSELECTEVENT(lParam)) {
843 ret = recv(s, buf, sizeof(buf), 0);
844 if (ret < 0 && WSAGetLastError() == WSAEWOULDBLOCK)
846 if (ret < 0) /* any _other_ error */
847 return -10000-WSAGetLastError();
852 ssh_gotdata (buf, ret);
855 return 1; /* shouldn't happen, but WTF */
859 * Called to send data down the Telnet connection.
861 static void ssh_send (char *buf, int len) {
862 if (s == INVALID_SOCKET)
865 ssh_protocol(buf, len, 0);
869 * Called to set the size of the window from Telnet's POV.
871 static void ssh_size(void) {
873 case SSH_STATE_BEFORE_SIZE:
874 case SSH_STATE_CLOSED:
875 break; /* do nothing */
876 case SSH_STATE_INTERMED:
877 size_needed = TRUE; /* buffer for later */
879 case SSH_STATE_SESSION:
881 s_wrpkt_start(11, 16);
882 pktout.body[0] = (rows >> 24) & 0xFF;
883 pktout.body[1] = (rows >> 16) & 0xFF;
884 pktout.body[2] = (rows >> 8) & 0xFF;
885 pktout.body[3] = rows & 0xFF;
886 pktout.body[4] = (cols >> 24) & 0xFF;
887 pktout.body[5] = (cols >> 16) & 0xFF;
888 pktout.body[6] = (cols >> 8) & 0xFF;
889 pktout.body[7] = cols & 0xFF;
890 memset(pktout.body+8, 0, 8);
897 * (Send Telnet special codes)
899 static void ssh_special (Telnet_Special code) {
903 Backend ssh_backend = {