2 * scpssh.c - SSH implementation for PuTTY Secure Copy
3 * Joris van Rantwijk, Aug 1999.
4 * Based on PuTTY ssh.c by Simon Tatham.
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_EXEC_CMD 13
22 #define SSH_SMSG_SUCCESS 14
23 #define SSH_SMSG_FAILURE 15
24 #define SSH_CMSG_STDIN_DATA 16
25 #define SSH_SMSG_STDOUT_DATA 17
26 #define SSH_SMSG_STDERR_DATA 18
27 #define SSH_CMSG_EOF 19
28 #define SSH_SMSG_EXIT_STATUS 20
29 #define SSH_CMSG_EXIT_CONFIRMATION 33
30 #define SSH_MSG_DEBUG 36
32 #define GET_32BIT(cp) \
33 (((unsigned long)(unsigned char)(cp)[0] << 24) | \
34 ((unsigned long)(unsigned char)(cp)[1] << 16) | \
35 ((unsigned long)(unsigned char)(cp)[2] << 8) | \
36 ((unsigned long)(unsigned char)(cp)[3]))
38 #define PUT_32BIT(cp, value) { \
39 (cp)[0] = (value) >> 24; \
40 (cp)[1] = (value) >> 16; \
41 (cp)[2] = (value) >> 8; \
44 static SOCKET s
= INVALID_SOCKET
;
46 static unsigned char session_key
[32];
47 static struct ssh_cipher
*cipher
= NULL
;
49 static char *savedhost
;
60 static struct Packet pktin
= { 0, 0, 0, NULL
, 0 };
61 static struct Packet pktout
= { 0, 0, 0, NULL
, 0 };
64 static void s_write (char *buf
, int len
) {
66 int i
= send (s
, buf
, len
, 0);
69 fatalbox("Lost connection while sending");
74 static int s_read (char *buf
, int len
) {
77 int i
= recv (s
, buf
, len
, 0);
80 len
-= i
, buf
+= i
, ret
+= i
;
88 * Read and decrypt one incoming SSH packet.
90 static void get_packet()
101 ret
= s_read(buf
, 4);
108 len
= GET_32BIT(buf
);
111 if (len
== 0x52656d6f) {
118 len
-= 5; /* type and CRC */
121 if (pktin
.maxlen
< biglen
) {
122 pktin
.maxlen
= biglen
;
123 pktin
.data
= (pktin
.data
== NULL
) ?
124 smalloc(biglen
) : srealloc(pktin
.data
, biglen
);
127 ret
= s_read(pktin
.data
, biglen
);
135 cipher
->decrypt(pktin
.data
, biglen
);
137 pktin
.type
= pktin
.data
[pad
];
138 pktin
.body
= pktin
.data
+ pad
+ 1;
140 if (pktin
.type
== SSH_MSG_DEBUG
) {
142 int len
= GET_32BIT(pktin
.body
);
143 fprintf(stderr
, "Remote: ");
144 fwrite(pktin
.body
+ 4, len
, 1, stderr
);
145 fprintf(stderr
, "\n");
151 static void s_wrpkt_start(int type
, int len
) {
154 len
+= 5; /* type and CRC */
158 pktout
.length
= len
-5;
159 if (pktout
.maxlen
< biglen
) {
160 pktout
.maxlen
= biglen
;
161 pktout
.data
= (pktout
.data
== NULL ?
malloc(biglen
+4) :
162 realloc(pktout
.data
, biglen
+4));
164 fatalbox("Out of memory");
168 pktout
.body
= pktout
.data
+4+pad
+1;
171 static void s_wrpkt(void) {
172 int pad
, len
, biglen
, i
;
175 len
= pktout
.length
+ 5; /* type and CRC */
179 pktout
.body
[-1] = pktout
.type
;
180 for (i
=0; i
<pad
; i
++)
181 pktout
.data
[i
+4] = random_byte();
182 crc
= crc32(pktout
.data
+4, biglen
-4);
183 PUT_32BIT(pktout
.data
+biglen
, crc
);
184 PUT_32BIT(pktout
.data
, len
);
187 cipher
->encrypt(pktout
.data
+4, biglen
);
189 s_write(pktout
.data
, biglen
+4);
192 static int do_ssh_init(void) {
200 while (s_read(&c
, 1) == 1) {
201 if (c
== 'S' && i
< 2) i
++;
202 else if (c
== 'S' && i
== 2) i
= 2;
203 else if (c
== 'H' && i
== 2) break;
207 if (s_read(&c
,1) != 1 || c
!= 'S') return 0;
208 if (s_read(&c
,1) != 1 || c
!= 'S') return 0;
209 if (s_read(&c
,1) != 1 || c
!= 'H') return 0;
211 if (s_read(&c
,1) != 1 || c
!= '-') return 0;
214 if (s_read(&c
,1) != 1)
220 } else if (i
< sizeof(version
)-1)
227 sprintf(vstring
, "SSH-%s-7.7.7\n",
228 (strcmp(version
, "1.5") <= 0 ? version
: "1.5"));
229 s_write(vstring
, strlen(vstring
));
235 * Login on the server and request execution of the command.
237 static void ssh_login(char *username
, char *cmd
)
240 unsigned char session_id
[16];
241 unsigned char *rsabuf
, *keystr1
, *keystr2
;
242 unsigned char cookie
[8];
243 struct RSAKey servkey
, hostkey
;
244 struct MD5Context md5c
;
245 unsigned long supported_ciphers_mask
;
248 extern struct ssh_cipher ssh_3des
;
249 extern struct ssh_cipher ssh_blowfish
;
253 if (pktin
.type
!= SSH_SMSG_PUBLIC_KEY
)
254 fatalbox("Public key packet not received");
256 memcpy(cookie
, pktin
.body
, 8);
260 i
= makekey(pktin
.body
+8, &servkey
, &keystr1
);
261 j
= makekey(pktin
.body
+8+i
, &hostkey
, &keystr2
);
263 supported_ciphers_mask
= GET_32BIT(pktin
.body
+12+i
+j
);
265 MD5Update(&md5c
, keystr2
, hostkey
.bytes
);
266 MD5Update(&md5c
, keystr1
, servkey
.bytes
);
267 MD5Update(&md5c
, pktin
.body
, 8);
269 MD5Final(session_id
, &md5c
);
272 session_key
[i
] = random_byte();
274 len
= (hostkey
.bytes
> servkey
.bytes ? hostkey
.bytes
: servkey
.bytes
);
276 rsabuf
= malloc(len
);
278 fatalbox("Out of memory");
280 verify_ssh_host_key(savedhost
, &hostkey
);
282 for (i
=0; i
<32; i
++) {
283 rsabuf
[i
] = session_key
[i
];
285 rsabuf
[i
] ^= session_id
[i
];
288 if (hostkey
.bytes
> servkey
.bytes
) {
289 rsaencrypt(rsabuf
, 32, &servkey
);
290 rsaencrypt(rsabuf
, servkey
.bytes
, &hostkey
);
292 rsaencrypt(rsabuf
, 32, &hostkey
);
293 rsaencrypt(rsabuf
, hostkey
.bytes
, &servkey
);
296 cipher_type
= cfg
.cipher
== CIPHER_BLOWFISH ? SSH_CIPHER_BLOWFISH
:
298 if ((supported_ciphers_mask
& (1 << cipher_type
)) == 0) {
299 fprintf(stderr
, "Selected cipher not supported, falling back to 3DES\n");
300 cipher_type
= SSH_CIPHER_3DES
;
303 s_wrpkt_start(SSH_CMSG_SESSION_KEY
, len
+15);
304 pktout
.body
[0] = cipher_type
;
305 memcpy(pktout
.body
+1, cookie
, 8);
306 pktout
.body
[9] = (len
*8) >> 8;
307 pktout
.body
[10] = (len
*8) & 0xFF;
308 memcpy(pktout
.body
+11, rsabuf
, len
);
309 pktout
.body
[len
+11] = pktout
.body
[len
+12] = 0; /* protocol flags */
310 pktout
.body
[len
+13] = pktout
.body
[len
+14] = 0;
315 cipher
= cipher_type
== SSH_CIPHER_BLOWFISH ?
&ssh_blowfish
:
317 cipher
->sesskey(session_key
);
321 if (pktin
.type
!= SSH_SMSG_SUCCESS
)
322 fatalbox("Encryption not successfully enabled");
325 fprintf(stderr
, "Logging in as \"%s\".\n", username
);
326 s_wrpkt_start(SSH_CMSG_USER
, 4+strlen(username
));
327 pktout
.body
[0] = pktout
.body
[1] = pktout
.body
[2] = 0;
328 pktout
.body
[3] = strlen(username
);
329 memcpy(pktout
.body
+4, username
, strlen(username
));
334 while (pktin
.type
== SSH_SMSG_FAILURE
) {
337 sprintf(prompt
, "%s@%s's password: ", username
, savedhost
);
338 ssh_get_password(prompt
, password
, 100);
339 s_wrpkt_start(SSH_CMSG_AUTH_PASSWORD
, 4+strlen(password
));
340 pktout
.body
[0] = pktout
.body
[1] = pktout
.body
[2] = 0;
341 pktout
.body
[3] = strlen(password
);
342 memcpy(pktout
.body
+4, password
, strlen(password
));
344 memset(password
, 0, strlen(password
));
346 if (pktin
.type
== SSH_SMSG_FAILURE
) {
347 fprintf(stderr
, "Access denied\n");
348 } else if (pktin
.type
!= SSH_SMSG_SUCCESS
) {
349 fatalbox("Strange packet received, type %d", pktin
.type
);
353 /* Execute command */
355 fprintf(stderr
, "Sending command: %s\n", cmd
);
357 s_wrpkt_start(SSH_CMSG_EXEC_CMD
, 4+i
);
358 PUT_32BIT(pktout
.body
, i
);
359 memcpy(pktout
.body
+4, cmd
, i
);
365 * Receive a block of data over the SSH link. Block until
366 * all data is available. Return nr of bytes read (0 if lost connection).
368 int ssh_recv(unsigned char *buf
, int len
)
370 static int pending_input_len
= 0;
371 static unsigned char *pending_input_ptr
;
374 if (pending_input_len
>= to_read
) {
375 memcpy(buf
, pending_input_ptr
, to_read
);
376 pending_input_ptr
+= to_read
;
377 pending_input_len
-= to_read
;
381 if (pending_input_len
> 0) {
382 memcpy(buf
, pending_input_ptr
, pending_input_len
);
383 buf
+= pending_input_len
;
384 to_read
-= pending_input_len
;
385 pending_input_len
= 0;
388 if (s
== INVALID_SOCKET
)
390 while (to_read
> 0) {
392 if (s
== INVALID_SOCKET
)
394 if (pktin
.type
== SSH_SMSG_STDOUT_DATA
) {
395 int plen
= GET_32BIT(pktin
.body
);
396 if (plen
<= to_read
) {
397 memcpy(buf
, pktin
.body
+ 4, plen
);
401 memcpy(buf
, pktin
.body
+ 4, to_read
);
402 pending_input_len
= plen
- to_read
;
403 pending_input_ptr
= pktin
.body
+ 4 + to_read
;
406 } else if (pktin
.type
== SSH_SMSG_STDERR_DATA
) {
407 int plen
= GET_32BIT(pktin
.body
);
408 fwrite(pktin
.body
+ 4, plen
, 1, stderr
);
409 } else if (pktin
.type
== SSH_MSG_DISCONNECT
) {
410 } else if (pktin
.type
== SSH_SMSG_SUCCESS
||
411 pktin
.type
== SSH_SMSG_FAILURE
) {
412 } else if (pktin
.type
== SSH_SMSG_EXIT_STATUS
) {
414 fprintf(stderr
, "Remote exit status %d\n",
415 GET_32BIT(pktin
.body
));
416 s_wrpkt_start(SSH_CMSG_EXIT_CONFIRMATION
, 0);
419 fprintf(stderr
, "Closing connection\n");
430 * Send a block of data over the SSH link.
431 * Block until all data is sent.
433 void ssh_send(unsigned char *buf
, int len
)
435 if (s
== INVALID_SOCKET
)
437 s_wrpkt_start(SSH_CMSG_STDIN_DATA
, 4 + len
);
438 PUT_32BIT(pktout
.body
, len
);
439 memcpy(pktout
.body
+ 4, buf
, len
);
445 * Send an EOF notification to the server.
447 void ssh_send_eof(void)
449 if (s
== INVALID_SOCKET
)
451 s_wrpkt_start(SSH_CMSG_EOF
, 0);
457 * Set up the connection, login on the remote host and
458 * start execution of a command.
460 * Returns an error message, or NULL on success.
462 * Also places the canonical host name into `realhost'.
464 char *ssh_init(char *host
, int port
, char *cmd
, char **realhost
) {
473 savedhost
= malloc(1+strlen(host
));
475 fatalbox("Out of memory");
476 strcpy(savedhost
, host
);
488 if ( (a
= inet_addr(host
)) == (unsigned long) INADDR_NONE
) {
489 if ( (h
= gethostbyname(host
)) == NULL
)
490 switch (WSAGetLastError()) {
491 case WSAENETDOWN
: return "Network is down";
492 case WSAHOST_NOT_FOUND
: case WSANO_DATA
:
493 return "Host does not exist";
494 case WSATRY_AGAIN
: return "Host not found";
495 default: return "gethostbyname: unknown error";
497 memcpy (&a
, h
->h_addr
, sizeof(a
));
498 *realhost
= h
->h_name
;
507 port
= 22; /* default ssh port */
512 s
= socket(AF_INET
, SOCK_STREAM
, 0);
513 if (s
== INVALID_SOCKET
)
514 switch (WSAGetLastError()) {
515 case WSAENETDOWN
: return "Network is down";
516 case WSAEAFNOSUPPORT
: return "TCP/IP support not present";
517 default: return "socket(): unknown error";
521 * Bind to local address.
523 addr
.sin_family
= AF_INET
;
524 addr
.sin_addr
.s_addr
= htonl(INADDR_ANY
);
525 addr
.sin_port
= htons(0);
526 if (bind (s
, (struct sockaddr
*)&addr
, sizeof(addr
)) == SOCKET_ERROR
)
527 switch (WSAGetLastError()) {
528 case WSAENETDOWN
: return "Network is down";
529 default: return "bind(): unknown error";
533 * Connect to remote address.
535 addr
.sin_addr
.s_addr
= htonl(a
);
536 addr
.sin_port
= htons((short)port
);
537 if (connect (s
, (struct sockaddr
*)&addr
, sizeof(addr
)) == SOCKET_ERROR
)
538 switch (WSAGetLastError()) {
539 case WSAENETDOWN
: return "Network is down";
540 case WSAECONNREFUSED
: return "Connection refused";
541 case WSAENETUNREACH
: return "Network is unreachable";
542 case WSAEHOSTUNREACH
: return "No route to host";
543 default: return "connect(): unknown error";
547 send(s
, "connect ", 8, 0);
548 send(s
, FWhost
, strlen(FWhost
), 0);
551 sprintf(buf
, " %d\n", FWport
);
552 send (s
, buf
, strlen(buf
), 0);
559 return "Protocol initialisation error";
561 ssh_login(cfg
.username
, cmd
);