blob: 56080cbb118c4feb40aa12b917cc28b625bcdbe4 [file] [log] [blame]
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001/*
Damien Miller4af51302000-04-16 11:18:38 +10002 *
Damien Miller95def091999-11-25 00:26:21 +11003 * packet.c
Damien Miller4af51302000-04-16 11:18:38 +10004 *
Damien Miller95def091999-11-25 00:26:21 +11005 * Author: Tatu Ylonen <ylo@cs.hut.fi>
Damien Miller4af51302000-04-16 11:18:38 +10006 *
Damien Miller95def091999-11-25 00:26:21 +11007 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
8 * All rights reserved
Damien Miller4af51302000-04-16 11:18:38 +10009 *
Damien Miller95def091999-11-25 00:26:21 +110010 * Created: Sat Mar 18 02:40:40 1995 ylo
Damien Miller4af51302000-04-16 11:18:38 +100011 *
Damien Miller95def091999-11-25 00:26:21 +110012 * This file contains code implementing the packet protocol and communication
13 * with the other side. This same code is used both on client and server side.
Damien Miller33b13562000-04-04 14:38:59 +100014 *
15 * SSH2 packet format added by Markus Friedl.
16 *
Damien Miller95def091999-11-25 00:26:21 +110017 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100018
19#include "includes.h"
Damien Miller6536c7d2000-06-22 21:32:31 +100020RCSID("$OpenBSD: packet.c,v 1.33 2000/06/20 01:39:43 markus Exp $");
Damien Millerd4a8b7e1999-10-27 13:42:43 +100021
22#include "xmalloc.h"
23#include "buffer.h"
24#include "packet.h"
25#include "bufaux.h"
26#include "ssh.h"
27#include "crc32.h"
28#include "cipher.h"
29#include "getput.h"
30
31#include "compress.h"
32#include "deattack.h"
Damien Millerb38eff82000-04-01 11:09:21 +100033#include "channels.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100034
Damien Miller33b13562000-04-04 14:38:59 +100035#include "compat.h"
36#include "ssh2.h"
37
Damien Miller5f056372000-04-16 12:31:48 +100038#include <openssl/bn.h>
39#include <openssl/dh.h>
40#include <openssl/hmac.h>
Damien Miller33b13562000-04-04 14:38:59 +100041#include "buffer.h"
42#include "kex.h"
43#include "hmac.h"
44
45#ifdef PACKET_DEBUG
46#define DBG(x) x
47#else
48#define DBG(x)
49#endif
50
Damien Miller5428f641999-11-25 11:54:57 +110051/*
52 * This variable contains the file descriptors used for communicating with
53 * the other side. connection_in is used for reading; connection_out for
54 * writing. These can be the same descriptor, in which case it is assumed to
55 * be a socket.
56 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100057static int connection_in = -1;
58static int connection_out = -1;
59
Damien Miller5428f641999-11-25 11:54:57 +110060/*
61 * Cipher type. This value is only used to determine whether to pad the
62 * packets with zeroes or random data.
63 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100064static int cipher_type = SSH_CIPHER_NONE;
65
66/* Protocol flags for the remote side. */
67static unsigned int remote_protocol_flags = 0;
68
69/* Encryption context for receiving data. This is only used for decryption. */
70static CipherContext receive_context;
Damien Miller95def091999-11-25 00:26:21 +110071
72/* Encryption context for sending data. This is only used for encryption. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100073static CipherContext send_context;
74
75/* Buffer for raw input data from the socket. */
76static Buffer input;
77
78/* Buffer for raw output data going to the socket. */
79static Buffer output;
80
81/* Buffer for the partial outgoing packet being constructed. */
82static Buffer outgoing_packet;
83
84/* Buffer for the incoming packet currently being processed. */
85static Buffer incoming_packet;
86
87/* Scratch buffer for packet compression/decompression. */
88static Buffer compression_buffer;
89
90/* Flag indicating whether packet compression/decompression is enabled. */
91static int packet_compression = 0;
92
Damien Miller6162d121999-11-21 13:23:52 +110093/* default maximum packet size */
94int max_packet_size = 32768;
95
Damien Millerd4a8b7e1999-10-27 13:42:43 +100096/* Flag indicating whether this module has been initialized. */
97static int initialized = 0;
98
99/* Set to true if the connection is interactive. */
100static int interactive_mode = 0;
101
Damien Miller33b13562000-04-04 14:38:59 +1000102/* True if SSH2 packet format is used */
103int use_ssh2_packet_format = 0;
104
105/* Session key information for Encryption and MAC */
106Kex *kex = NULL;
107
108void
109packet_set_kex(Kex *k)
110{
111 if( k->mac[MODE_IN ].key == NULL ||
112 k->enc[MODE_IN ].key == NULL ||
113 k->enc[MODE_IN ].iv == NULL ||
114 k->mac[MODE_OUT].key == NULL ||
115 k->enc[MODE_OUT].key == NULL ||
116 k->enc[MODE_OUT].iv == NULL)
117 fatal("bad KEX");
118 kex = k;
119}
120void
121clear_enc_keys(Enc *enc, int len)
122{
123 memset(enc->iv, 0, len);
124 memset(enc->key, 0, len);
125 xfree(enc->iv);
126 xfree(enc->key);
127 enc->iv = NULL;
128 enc->key = NULL;
129}
130void
131packet_set_ssh2_format(void)
132{
Damien Miller35dabd02000-05-01 21:10:33 +1000133 DBG(debug("use_ssh2_packet_format"));
Damien Miller33b13562000-04-04 14:38:59 +1000134 use_ssh2_packet_format = 1;
135}
136
Damien Miller5428f641999-11-25 11:54:57 +1100137/*
138 * Sets the descriptors used for communication. Disables encryption until
139 * packet_set_encryption_key is called.
140 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000141void
142packet_set_connection(int fd_in, int fd_out)
143{
Damien Miller95def091999-11-25 00:26:21 +1100144 connection_in = fd_in;
145 connection_out = fd_out;
146 cipher_type = SSH_CIPHER_NONE;
Damien Miller1383bd82000-04-06 12:32:37 +1000147 cipher_set_key(&send_context, SSH_CIPHER_NONE, (unsigned char *) "", 0);
148 cipher_set_key(&receive_context, SSH_CIPHER_NONE, (unsigned char *) "", 0);
Damien Miller95def091999-11-25 00:26:21 +1100149 if (!initialized) {
150 initialized = 1;
151 buffer_init(&input);
152 buffer_init(&output);
153 buffer_init(&outgoing_packet);
154 buffer_init(&incoming_packet);
155 }
156 /* Kludge: arrange the close function to be called from fatal(). */
157 fatal_add_cleanup((void (*) (void *)) packet_close, NULL);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000158}
159
Damien Miller34132e52000-01-14 15:45:46 +1100160/* Returns 1 if remote host is connected via socket, 0 if not. */
161
162int
163packet_connection_is_on_socket()
164{
165 struct sockaddr_storage from, to;
166 socklen_t fromlen, tolen;
167
168 /* filedescriptors in and out are the same, so it's a socket */
169 if (connection_in == connection_out)
170 return 1;
171 fromlen = sizeof(from);
172 memset(&from, 0, sizeof(from));
Damien Millerf052aaf2000-01-22 19:47:21 +1100173 if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0)
Damien Miller34132e52000-01-14 15:45:46 +1100174 return 0;
175 tolen = sizeof(to);
176 memset(&to, 0, sizeof(to));
Damien Millerf052aaf2000-01-22 19:47:21 +1100177 if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0)
Damien Miller34132e52000-01-14 15:45:46 +1100178 return 0;
179 if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
180 return 0;
181 if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
182 return 0;
183 return 1;
184}
185
186/* returns 1 if connection is via ipv4 */
187
188int
189packet_connection_is_ipv4()
190{
191 struct sockaddr_storage to;
Damien Miller6fe375d2000-01-23 09:38:00 +1100192 socklen_t tolen = sizeof(to);
Damien Miller34132e52000-01-14 15:45:46 +1100193
194 memset(&to, 0, sizeof(to));
195 if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0)
196 return 0;
197 if (to.ss_family != AF_INET)
198 return 0;
199 return 1;
200}
201
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000202/* Sets the connection into non-blocking mode. */
203
204void
205packet_set_nonblocking()
206{
Damien Miller95def091999-11-25 00:26:21 +1100207 /* Set the socket into non-blocking mode. */
208 if (fcntl(connection_in, F_SETFL, O_NONBLOCK) < 0)
209 error("fcntl O_NONBLOCK: %.100s", strerror(errno));
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000210
Damien Miller95def091999-11-25 00:26:21 +1100211 if (connection_out != connection_in) {
212 if (fcntl(connection_out, F_SETFL, O_NONBLOCK) < 0)
213 error("fcntl O_NONBLOCK: %.100s", strerror(errno));
214 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000215}
216
217/* Returns the socket used for reading. */
218
219int
220packet_get_connection_in()
221{
Damien Miller95def091999-11-25 00:26:21 +1100222 return connection_in;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000223}
224
225/* Returns the descriptor used for writing. */
226
227int
228packet_get_connection_out()
229{
Damien Miller95def091999-11-25 00:26:21 +1100230 return connection_out;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000231}
232
233/* Closes the connection and clears and frees internal data structures. */
234
235void
236packet_close()
237{
Damien Miller95def091999-11-25 00:26:21 +1100238 if (!initialized)
239 return;
240 initialized = 0;
241 if (connection_in == connection_out) {
242 shutdown(connection_out, SHUT_RDWR);
243 close(connection_out);
244 } else {
245 close(connection_in);
246 close(connection_out);
247 }
248 buffer_free(&input);
249 buffer_free(&output);
250 buffer_free(&outgoing_packet);
251 buffer_free(&incoming_packet);
252 if (packet_compression) {
253 buffer_free(&compression_buffer);
254 buffer_compress_uninit();
255 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000256}
257
258/* Sets remote side protocol flags. */
259
260void
261packet_set_protocol_flags(unsigned int protocol_flags)
262{
Damien Miller95def091999-11-25 00:26:21 +1100263 remote_protocol_flags = protocol_flags;
264 channel_set_options((protocol_flags & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) != 0);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000265}
266
267/* Returns the remote protocol flags set earlier by the above function. */
268
269unsigned int
270packet_get_protocol_flags()
271{
Damien Miller95def091999-11-25 00:26:21 +1100272 return remote_protocol_flags;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000273}
274
Damien Miller5428f641999-11-25 11:54:57 +1100275/*
276 * Starts packet compression from the next packet on in both directions.
277 * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
278 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000279
Damien Miller33b13562000-04-04 14:38:59 +1000280/*** XXXXX todo: kex means re-init */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000281void
282packet_start_compression(int level)
283{
Damien Miller95def091999-11-25 00:26:21 +1100284 if (packet_compression)
285 fatal("Compression already enabled.");
286 packet_compression = 1;
287 buffer_init(&compression_buffer);
288 buffer_compress_init(level);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000289}
290
Damien Miller5428f641999-11-25 11:54:57 +1100291/*
292 * Encrypts the given number of bytes, copying from src to dest. bytes is
293 * known to be a multiple of 8.
294 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000295
296void
Damien Miller95def091999-11-25 00:26:21 +1100297packet_encrypt(CipherContext * cc, void *dest, void *src,
Damien Miller33b13562000-04-04 14:38:59 +1000298 unsigned int bytes)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000299{
Damien Miller95def091999-11-25 00:26:21 +1100300 cipher_encrypt(cc, dest, src, bytes);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000301}
302
Damien Miller5428f641999-11-25 11:54:57 +1100303/*
304 * Decrypts the given number of bytes, copying from src to dest. bytes is
305 * known to be a multiple of 8.
306 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000307
308void
Damien Miller95def091999-11-25 00:26:21 +1100309packet_decrypt(CipherContext * cc, void *dest, void *src,
Damien Miller33b13562000-04-04 14:38:59 +1000310 unsigned int bytes)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000311{
Damien Miller95def091999-11-25 00:26:21 +1100312 int i;
313
314 if ((bytes % 8) != 0)
315 fatal("packet_decrypt: bad ciphertext length %d", bytes);
316
Damien Miller5428f641999-11-25 11:54:57 +1100317 /*
318 * Cryptographic attack detector for ssh - Modifications for packet.c
319 * (C)1998 CORE-SDI, Buenos Aires Argentina Ariel Futoransky(futo@core-sdi.com)
320 */
Damien Miller95def091999-11-25 00:26:21 +1100321
Damien Miller33b13562000-04-04 14:38:59 +1000322 if (cc->type == SSH_CIPHER_NONE || compat20) {
Damien Miller95def091999-11-25 00:26:21 +1100323 i = DEATTACK_OK;
Damien Miller33b13562000-04-04 14:38:59 +1000324 } else {
Damien Miller95def091999-11-25 00:26:21 +1100325 i = detect_attack(src, bytes, NULL);
Damien Miller95def091999-11-25 00:26:21 +1100326 }
Damien Miller95def091999-11-25 00:26:21 +1100327 if (i == DEATTACK_DETECTED)
328 packet_disconnect("crc32 compensation attack: network attack detected");
329
330 cipher_decrypt(cc, dest, src, bytes);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000331}
332
Damien Miller5428f641999-11-25 11:54:57 +1100333/*
334 * Causes any further packets to be encrypted using the given key. The same
335 * key is used for both sending and reception. However, both directions are
336 * encrypted independently of each other.
337 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000338
339void
340packet_set_encryption_key(const unsigned char *key, unsigned int keylen,
Damien Miller33b13562000-04-04 14:38:59 +1000341 int cipher)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000342{
Damien Miller33b13562000-04-04 14:38:59 +1000343 if (keylen < 20)
344 fatal("keylen too small: %d", keylen);
345
Damien Miller95def091999-11-25 00:26:21 +1100346 /* All other ciphers use the same key in both directions for now. */
Damien Miller1383bd82000-04-06 12:32:37 +1000347 cipher_set_key(&receive_context, cipher, key, keylen);
348 cipher_set_key(&send_context, cipher, key, keylen);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000349}
350
351/* Starts constructing a packet to send. */
352
353void
Damien Miller33b13562000-04-04 14:38:59 +1000354packet_start1(int type)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000355{
Damien Miller95def091999-11-25 00:26:21 +1100356 char buf[9];
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000357
Damien Miller95def091999-11-25 00:26:21 +1100358 buffer_clear(&outgoing_packet);
359 memset(buf, 0, 8);
360 buf[8] = type;
361 buffer_append(&outgoing_packet, buf, 9);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000362}
363
Damien Miller33b13562000-04-04 14:38:59 +1000364void
365packet_start2(int type)
366{
367 char buf[4+1+1];
368
369 buffer_clear(&outgoing_packet);
370 memset(buf, 0, sizeof buf);
371 /* buf[0..3] = payload_len; */
372 /* buf[4] = pad_len; */
373 buf[5] = type & 0xff;
374 buffer_append(&outgoing_packet, buf, sizeof buf);
375}
376
377void
378packet_start(int type)
379{
380 DBG(debug("packet_start[%d]",type));
381 if (use_ssh2_packet_format)
382 packet_start2(type);
383 else
384 packet_start1(type);
385}
386
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000387/* Appends a character to the packet data. */
388
389void
390packet_put_char(int value)
391{
Damien Miller95def091999-11-25 00:26:21 +1100392 char ch = value;
393 buffer_append(&outgoing_packet, &ch, 1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000394}
395
396/* Appends an integer to the packet data. */
397
398void
399packet_put_int(unsigned int value)
400{
Damien Miller95def091999-11-25 00:26:21 +1100401 buffer_put_int(&outgoing_packet, value);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000402}
403
404/* Appends a string to packet data. */
405
406void
407packet_put_string(const char *buf, unsigned int len)
408{
Damien Miller95def091999-11-25 00:26:21 +1100409 buffer_put_string(&outgoing_packet, buf, len);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000410}
Damien Miller33b13562000-04-04 14:38:59 +1000411void
412packet_put_cstring(const char *str)
413{
414 buffer_put_string(&outgoing_packet, str, strlen(str));
415}
416
417void
418packet_put_raw(const char *buf, unsigned int len)
419{
420 buffer_append(&outgoing_packet, buf, len);
421}
422
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000423
424/* Appends an arbitrary precision integer to packet data. */
425
426void
Damien Miller95def091999-11-25 00:26:21 +1100427packet_put_bignum(BIGNUM * value)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000428{
Damien Miller95def091999-11-25 00:26:21 +1100429 buffer_put_bignum(&outgoing_packet, value);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000430}
Damien Miller33b13562000-04-04 14:38:59 +1000431void
432packet_put_bignum2(BIGNUM * value)
433{
434 buffer_put_bignum2(&outgoing_packet, value);
435}
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000436
Damien Miller5428f641999-11-25 11:54:57 +1100437/*
438 * Finalizes and sends the packet. If the encryption key has been set,
439 * encrypts the packet before sending.
440 */
Damien Miller95def091999-11-25 00:26:21 +1100441
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000442void
Damien Miller33b13562000-04-04 14:38:59 +1000443packet_send1()
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000444{
Damien Miller95def091999-11-25 00:26:21 +1100445 char buf[8], *cp;
446 int i, padding, len;
447 unsigned int checksum;
448 u_int32_t rand = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000449
Damien Miller5428f641999-11-25 11:54:57 +1100450 /*
451 * If using packet compression, compress the payload of the outgoing
452 * packet.
453 */
Damien Miller95def091999-11-25 00:26:21 +1100454 if (packet_compression) {
455 buffer_clear(&compression_buffer);
456 /* Skip padding. */
457 buffer_consume(&outgoing_packet, 8);
458 /* padding */
459 buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8);
460 buffer_compress(&outgoing_packet, &compression_buffer);
461 buffer_clear(&outgoing_packet);
462 buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
463 buffer_len(&compression_buffer));
464 }
465 /* Compute packet length without padding (add checksum, remove padding). */
466 len = buffer_len(&outgoing_packet) + 4 - 8;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000467
Damien Millere247cc42000-05-07 12:03:14 +1000468 /* Insert padding. Initialized to zero in packet_start1() */
Damien Miller95def091999-11-25 00:26:21 +1100469 padding = 8 - len % 8;
470 if (cipher_type != SSH_CIPHER_NONE) {
471 cp = buffer_ptr(&outgoing_packet);
472 for (i = 0; i < padding; i++) {
473 if (i % 4 == 0)
474 rand = arc4random();
475 cp[7 - i] = rand & 0xff;
476 rand >>= 8;
477 }
478 }
479 buffer_consume(&outgoing_packet, 8 - padding);
480
481 /* Add check bytes. */
482 checksum = crc32((unsigned char *) buffer_ptr(&outgoing_packet),
483 buffer_len(&outgoing_packet));
484 PUT_32BIT(buf, checksum);
485 buffer_append(&outgoing_packet, buf, 4);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000486
487#ifdef PACKET_DEBUG
Damien Miller95def091999-11-25 00:26:21 +1100488 fprintf(stderr, "packet_send plain: ");
489 buffer_dump(&outgoing_packet);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000490#endif
491
Damien Miller95def091999-11-25 00:26:21 +1100492 /* Append to output. */
493 PUT_32BIT(buf, len);
494 buffer_append(&output, buf, 4);
495 buffer_append_space(&output, &cp, buffer_len(&outgoing_packet));
496 packet_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),
497 buffer_len(&outgoing_packet));
498
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000499#ifdef PACKET_DEBUG
Damien Miller95def091999-11-25 00:26:21 +1100500 fprintf(stderr, "encrypted: ");
501 buffer_dump(&output);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000502#endif
503
Damien Miller95def091999-11-25 00:26:21 +1100504 buffer_clear(&outgoing_packet);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000505
Damien Miller5428f641999-11-25 11:54:57 +1100506 /*
507 * Note that the packet is now only buffered in output. It won\'t be
508 * actually sent until packet_write_wait or packet_write_poll is
509 * called.
510 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000511}
512
Damien Miller5428f641999-11-25 11:54:57 +1100513/*
Damien Miller33b13562000-04-04 14:38:59 +1000514 * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
515 */
516void
517packet_send2()
518{
519 unsigned char *macbuf = NULL;
520 char *cp;
521 unsigned int packet_length = 0;
522 unsigned int i, padlen, len;
523 u_int32_t rand = 0;
Damien Miller4af51302000-04-16 11:18:38 +1000524 static unsigned int seqnr = 0;
Damien Miller33b13562000-04-04 14:38:59 +1000525 int type;
526 Enc *enc = NULL;
527 Mac *mac = NULL;
528 Comp *comp = NULL;
529 int block_size;
530
531 if (kex != NULL) {
532 enc = &kex->enc[MODE_OUT];
533 mac = &kex->mac[MODE_OUT];
534 comp = &kex->comp[MODE_OUT];
535 }
536 block_size = enc ? enc->block_size : 8;
537
538 cp = buffer_ptr(&outgoing_packet);
539 type = cp[5] & 0xff;
540
541#ifdef PACKET_DEBUG
542 fprintf(stderr, "plain: ");
543 buffer_dump(&outgoing_packet);
544#endif
545
546 if (comp && comp->enabled) {
547 len = buffer_len(&outgoing_packet);
548 /* skip header, compress only payload */
549 buffer_consume(&outgoing_packet, 5);
550 buffer_clear(&compression_buffer);
551 buffer_compress(&outgoing_packet, &compression_buffer);
552 buffer_clear(&outgoing_packet);
553 buffer_append(&outgoing_packet, "\0\0\0\0\0", 5);
554 buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
555 buffer_len(&compression_buffer));
556 DBG(debug("compression: raw %d compressed %d", len,
557 buffer_len(&outgoing_packet)));
558 }
559
560 /* sizeof (packet_len + pad_len + payload) */
561 len = buffer_len(&outgoing_packet);
562
563 /*
564 * calc size of padding, alloc space, get random data,
565 * minimum padding is 4 bytes
566 */
567 padlen = block_size - (len % block_size);
568 if (padlen < 4)
569 padlen += block_size;
570 buffer_append_space(&outgoing_packet, &cp, padlen);
571 if (enc && enc->type != SSH_CIPHER_NONE) {
Damien Millere247cc42000-05-07 12:03:14 +1000572 /* random padding */
Damien Miller33b13562000-04-04 14:38:59 +1000573 for (i = 0; i < padlen; i++) {
574 if (i % 4 == 0)
575 rand = arc4random();
576 cp[i] = rand & 0xff;
577 rand <<= 8;
578 }
Damien Millere247cc42000-05-07 12:03:14 +1000579 } else {
580 /* clear padding */
581 memset(cp, 0, padlen);
Damien Miller33b13562000-04-04 14:38:59 +1000582 }
583 /* packet_length includes payload, padding and padding length field */
584 packet_length = buffer_len(&outgoing_packet) - 4;
585 cp = buffer_ptr(&outgoing_packet);
586 PUT_32BIT(cp, packet_length);
587 cp[4] = padlen & 0xff;
588 DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen));
589
590 /* compute MAC over seqnr and packet(length fields, payload, padding) */
591 if (mac && mac->enabled) {
592 macbuf = hmac( mac->md, seqnr,
593 (unsigned char *) buffer_ptr(&outgoing_packet),
594 buffer_len(&outgoing_packet),
595 mac->key, mac->key_len
596 );
597 DBG(debug("done calc HMAC out #%d", seqnr));
598 }
599 /* encrypt packet and append to output buffer. */
600 buffer_append_space(&output, &cp, buffer_len(&outgoing_packet));
601 packet_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),
602 buffer_len(&outgoing_packet));
603 /* append unencrypted MAC */
604 if (mac && mac->enabled)
605 buffer_append(&output, (char *)macbuf, mac->mac_len);
606#ifdef PACKET_DEBUG
607 fprintf(stderr, "encrypted: ");
608 buffer_dump(&output);
609#endif
Damien Miller4af51302000-04-16 11:18:38 +1000610 /* increment sequence number for outgoing packets */
611 if (++seqnr == 0)
612 log("outgoing seqnr wraps around");
Damien Miller33b13562000-04-04 14:38:59 +1000613 buffer_clear(&outgoing_packet);
614
615 if (type == SSH2_MSG_NEWKEYS) {
616 if (kex==NULL || mac==NULL || enc==NULL || comp==NULL)
617 fatal("packet_send2: no KEX");
618 if (mac->md != NULL)
619 mac->enabled = 1;
Damien Miller35dabd02000-05-01 21:10:33 +1000620 DBG(debug("cipher_set_key_iv send_context"));
Damien Miller33b13562000-04-04 14:38:59 +1000621 cipher_set_key_iv(&send_context, enc->type,
622 enc->key, enc->key_len,
623 enc->iv, enc->iv_len);
624 clear_enc_keys(enc, kex->we_need);
625 if (comp->type != 0 && comp->enabled == 0) {
626 comp->enabled = 1;
627 if (! packet_compression)
628 packet_start_compression(6);
629 }
630 }
631}
632
633void
634packet_send()
635{
636 if (use_ssh2_packet_format)
637 packet_send2();
638 else
639 packet_send1();
640 DBG(debug("packet_send done"));
641}
642
Damien Miller33b13562000-04-04 14:38:59 +1000643/*
Damien Miller5428f641999-11-25 11:54:57 +1100644 * Waits until a packet has been received, and returns its type. Note that
645 * no other data is processed until this returns, so this function should not
646 * be used during the interactive session.
647 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000648
649int
650packet_read(int *payload_len_ptr)
651{
Damien Miller95def091999-11-25 00:26:21 +1100652 int type, len;
653 fd_set set;
654 char buf[8192];
Damien Miller33b13562000-04-04 14:38:59 +1000655 DBG(debug("packet_read()"));
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000656
Damien Miller95def091999-11-25 00:26:21 +1100657 /* Since we are blocking, ensure that all written packets have been sent. */
658 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000659
Damien Miller95def091999-11-25 00:26:21 +1100660 /* Stay in the loop until we have received a complete packet. */
661 for (;;) {
662 /* Try to read a packet from the buffer. */
663 type = packet_read_poll(payload_len_ptr);
Damien Millere247cc42000-05-07 12:03:14 +1000664 if (!use_ssh2_packet_format && (
665 type == SSH_SMSG_SUCCESS
Damien Miller95def091999-11-25 00:26:21 +1100666 || type == SSH_SMSG_FAILURE
667 || type == SSH_CMSG_EOF
Damien Millere247cc42000-05-07 12:03:14 +1000668 || type == SSH_CMSG_EXIT_CONFIRMATION))
Damien Miller95def091999-11-25 00:26:21 +1100669 packet_integrity_check(*payload_len_ptr, 0, type);
670 /* If we got a packet, return it. */
671 if (type != SSH_MSG_NONE)
672 return type;
Damien Miller5428f641999-11-25 11:54:57 +1100673 /*
674 * Otherwise, wait for some data to arrive, add it to the
675 * buffer, and try again.
676 */
Damien Miller95def091999-11-25 00:26:21 +1100677 FD_ZERO(&set);
678 FD_SET(connection_in, &set);
Damien Miller5428f641999-11-25 11:54:57 +1100679
Damien Miller95def091999-11-25 00:26:21 +1100680 /* Wait for some data to arrive. */
681 select(connection_in + 1, &set, NULL, NULL, NULL);
Damien Miller5428f641999-11-25 11:54:57 +1100682
Damien Miller95def091999-11-25 00:26:21 +1100683 /* Read data from the socket. */
684 len = read(connection_in, buf, sizeof(buf));
Damien Miller5e7c10e1999-12-16 13:18:04 +1100685 if (len == 0) {
686 log("Connection closed by %.200s", get_remote_ipaddr());
687 fatal_cleanup();
688 }
Damien Miller95def091999-11-25 00:26:21 +1100689 if (len < 0)
690 fatal("Read from socket failed: %.100s", strerror(errno));
691 /* Append it to the buffer. */
692 packet_process_incoming(buf, len);
693 }
694 /* NOTREACHED */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000695}
696
Damien Miller5428f641999-11-25 11:54:57 +1100697/*
698 * Waits until a packet has been received, verifies that its type matches
699 * that given, and gives a fatal error and exits if there is a mismatch.
700 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000701
702void
703packet_read_expect(int *payload_len_ptr, int expected_type)
704{
Damien Miller95def091999-11-25 00:26:21 +1100705 int type;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000706
Damien Miller95def091999-11-25 00:26:21 +1100707 type = packet_read(payload_len_ptr);
708 if (type != expected_type)
709 packet_disconnect("Protocol error: expected packet type %d, got %d",
Damien Miller33b13562000-04-04 14:38:59 +1000710 expected_type, type);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000711}
712
713/* Checks if a full packet is available in the data received so far via
Damien Miller95def091999-11-25 00:26:21 +1100714 * packet_process_incoming. If so, reads the packet; otherwise returns
715 * SSH_MSG_NONE. This does not wait for data from the connection.
716 *
717 * SSH_MSG_DISCONNECT is handled specially here. Also,
718 * SSH_MSG_IGNORE messages are skipped by this function and are never returned
719 * to higher levels.
720 *
721 * The returned payload_len does include space consumed by:
722 * Packet length
723 * Padding
724 * Packet type
725 * Check bytes
726 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000727
728int
Damien Miller33b13562000-04-04 14:38:59 +1000729packet_read_poll1(int *payload_len_ptr)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000730{
Damien Miller95def091999-11-25 00:26:21 +1100731 unsigned int len, padded_len;
732 unsigned char *ucp;
Damien Miller33b13562000-04-04 14:38:59 +1000733 char buf[8], *cp;
Damien Miller95def091999-11-25 00:26:21 +1100734 unsigned int checksum, stored_checksum;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000735
Damien Miller95def091999-11-25 00:26:21 +1100736 /* Check if input size is less than minimum packet size. */
737 if (buffer_len(&input) < 4 + 8)
738 return SSH_MSG_NONE;
739 /* Get length of incoming packet. */
740 ucp = (unsigned char *) buffer_ptr(&input);
741 len = GET_32BIT(ucp);
742 if (len < 1 + 2 + 2 || len > 256 * 1024)
743 packet_disconnect("Bad packet length %d.", len);
744 padded_len = (len + 8) & ~7;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000745
Damien Miller95def091999-11-25 00:26:21 +1100746 /* Check if the packet has been entirely received. */
747 if (buffer_len(&input) < 4 + padded_len)
748 return SSH_MSG_NONE;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000749
Damien Miller95def091999-11-25 00:26:21 +1100750 /* The entire packet is in buffer. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000751
Damien Miller95def091999-11-25 00:26:21 +1100752 /* Consume packet length. */
753 buffer_consume(&input, 4);
754
755 /* Copy data to incoming_packet. */
756 buffer_clear(&incoming_packet);
757 buffer_append_space(&incoming_packet, &cp, padded_len);
758 packet_decrypt(&receive_context, cp, buffer_ptr(&input), padded_len);
759 buffer_consume(&input, padded_len);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000760
761#ifdef PACKET_DEBUG
Damien Miller95def091999-11-25 00:26:21 +1100762 fprintf(stderr, "read_poll plain: ");
763 buffer_dump(&incoming_packet);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000764#endif
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000765
Damien Miller95def091999-11-25 00:26:21 +1100766 /* Compute packet checksum. */
767 checksum = crc32((unsigned char *) buffer_ptr(&incoming_packet),
Damien Miller33b13562000-04-04 14:38:59 +1000768 buffer_len(&incoming_packet) - 4);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000769
Damien Miller95def091999-11-25 00:26:21 +1100770 /* Skip padding. */
771 buffer_consume(&incoming_packet, 8 - len % 8);
Damien Millerfd7c9111999-11-08 16:15:55 +1100772
Damien Miller95def091999-11-25 00:26:21 +1100773 /* Test check bytes. */
Damien Millerfd7c9111999-11-08 16:15:55 +1100774
Damien Miller95def091999-11-25 00:26:21 +1100775 if (len != buffer_len(&incoming_packet))
776 packet_disconnect("packet_read_poll: len %d != buffer_len %d.",
Damien Miller33b13562000-04-04 14:38:59 +1000777 len, buffer_len(&incoming_packet));
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000778
Damien Miller95def091999-11-25 00:26:21 +1100779 ucp = (unsigned char *) buffer_ptr(&incoming_packet) + len - 4;
780 stored_checksum = GET_32BIT(ucp);
781 if (checksum != stored_checksum)
782 packet_disconnect("Corrupted check bytes on input.");
783 buffer_consume_end(&incoming_packet, 4);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000784
Damien Miller95def091999-11-25 00:26:21 +1100785 /* If using packet compression, decompress the packet. */
786 if (packet_compression) {
787 buffer_clear(&compression_buffer);
788 buffer_uncompress(&incoming_packet, &compression_buffer);
789 buffer_clear(&incoming_packet);
790 buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
Damien Miller33b13562000-04-04 14:38:59 +1000791 buffer_len(&compression_buffer));
Damien Miller95def091999-11-25 00:26:21 +1100792 }
793 /* Get packet type. */
794 buffer_get(&incoming_packet, &buf[0], 1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000795
Damien Miller95def091999-11-25 00:26:21 +1100796 /* Return length of payload (without type field). */
797 *payload_len_ptr = buffer_len(&incoming_packet);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000798
Damien Miller95def091999-11-25 00:26:21 +1100799 /* Return type. */
800 return (unsigned char) buf[0];
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000801}
Damien Miller95def091999-11-25 00:26:21 +1100802
Damien Miller33b13562000-04-04 14:38:59 +1000803int
804packet_read_poll2(int *payload_len_ptr)
805{
806 unsigned int padlen, need;
807 unsigned char buf[8], *macbuf;
808 unsigned char *ucp;
809 char *cp;
810 static unsigned int packet_length = 0;
811 static unsigned int seqnr = 0;
812 int type;
813 int maclen, block_size;
814 Enc *enc = NULL;
815 Mac *mac = NULL;
816 Comp *comp = NULL;
817
818 if (kex != NULL) {
819 enc = &kex->enc[MODE_IN];
820 mac = &kex->mac[MODE_IN];
821 comp = &kex->comp[MODE_IN];
822 }
823 maclen = mac && mac->enabled ? mac->mac_len : 0;
824 block_size = enc ? enc->block_size : 8;
825
826 if (packet_length == 0) {
827 /*
828 * check if input size is less than the cipher block size,
829 * decrypt first block and extract length of incoming packet
830 */
831 if (buffer_len(&input) < block_size)
832 return SSH_MSG_NONE;
833 buffer_clear(&incoming_packet);
834 buffer_append_space(&incoming_packet, &cp, block_size);
835 packet_decrypt(&receive_context, cp, buffer_ptr(&input),
836 block_size);
837 ucp = (unsigned char *) buffer_ptr(&incoming_packet);
838 packet_length = GET_32BIT(ucp);
839 if (packet_length < 1 + 4 || packet_length > 256 * 1024) {
840 buffer_dump(&incoming_packet);
841 packet_disconnect("Bad packet length %d.", packet_length);
842 }
843 DBG(debug("input: packet len %d", packet_length+4));
844 buffer_consume(&input, block_size);
845 }
846 /* we have a partial packet of block_size bytes */
847 need = 4 + packet_length - block_size;
848 DBG(debug("partial packet %d, need %d, maclen %d", block_size,
849 need, maclen));
850 if (need % block_size != 0)
851 fatal("padding error: need %d block %d mod %d",
852 need, block_size, need % block_size);
853 /*
854 * check if the entire packet has been received and
855 * decrypt into incoming_packet
856 */
857 if (buffer_len(&input) < need + maclen)
858 return SSH_MSG_NONE;
859#ifdef PACKET_DEBUG
860 fprintf(stderr, "read_poll enc/full: ");
861 buffer_dump(&input);
862#endif
863 buffer_append_space(&incoming_packet, &cp, need);
864 packet_decrypt(&receive_context, cp, buffer_ptr(&input), need);
865 buffer_consume(&input, need);
866 /*
867 * compute MAC over seqnr and packet,
868 * increment sequence number for incoming packet
869 */
Damien Miller4af51302000-04-16 11:18:38 +1000870 if (mac && mac->enabled) {
Damien Miller33b13562000-04-04 14:38:59 +1000871 macbuf = hmac( mac->md, seqnr,
872 (unsigned char *) buffer_ptr(&incoming_packet),
873 buffer_len(&incoming_packet),
874 mac->key, mac->key_len
875 );
876 if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0)
877 packet_disconnect("Corrupted HMAC on input.");
878 DBG(debug("HMAC #%d ok", seqnr));
879 buffer_consume(&input, mac->mac_len);
880 }
Damien Miller4af51302000-04-16 11:18:38 +1000881 if (++seqnr == 0)
882 log("incoming seqnr wraps around");
Damien Miller33b13562000-04-04 14:38:59 +1000883
884 /* get padlen */
885 cp = buffer_ptr(&incoming_packet) + 4;
886 padlen = *cp & 0xff;
887 DBG(debug("input: padlen %d", padlen));
888 if (padlen < 4)
889 packet_disconnect("Corrupted padlen %d on input.", padlen);
890
891 /* skip packet size + padlen, discard padding */
892 buffer_consume(&incoming_packet, 4 + 1);
893 buffer_consume_end(&incoming_packet, padlen);
894
895 DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet)));
896 if (comp && comp->enabled) {
897 buffer_clear(&compression_buffer);
898 buffer_uncompress(&incoming_packet, &compression_buffer);
899 buffer_clear(&incoming_packet);
900 buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
901 buffer_len(&compression_buffer));
902 DBG(debug("input: len after de-compress %d", buffer_len(&incoming_packet)));
903 }
904 /*
905 * get packet type, implies consume.
906 * return length of payload (without type field)
907 */
908 buffer_get(&incoming_packet, (char *)&buf[0], 1);
909 *payload_len_ptr = buffer_len(&incoming_packet);
910
911 /* reset for next packet */
912 packet_length = 0;
913
914 /* extract packet type */
915 type = (unsigned char)buf[0];
916
917 if (type == SSH2_MSG_NEWKEYS) {
918 if (kex==NULL || mac==NULL || enc==NULL || comp==NULL)
919 fatal("packet_read_poll2: no KEX");
920 if (mac->md != NULL)
921 mac->enabled = 1;
Damien Miller35dabd02000-05-01 21:10:33 +1000922 DBG(debug("cipher_set_key_iv receive_context"));
Damien Miller33b13562000-04-04 14:38:59 +1000923 cipher_set_key_iv(&receive_context, enc->type,
924 enc->key, enc->key_len,
925 enc->iv, enc->iv_len);
926 clear_enc_keys(enc, kex->we_need);
927 if (comp->type != 0 && comp->enabled == 0) {
928 comp->enabled = 1;
929 if (! packet_compression)
930 packet_start_compression(6);
931 }
932 }
933
934#ifdef PACKET_DEBUG
935 fprintf(stderr, "read/plain[%d]:\r\n",type);
936 buffer_dump(&incoming_packet);
937#endif
938 return (unsigned char)type;
939}
940
941int
942packet_read_poll(int *payload_len_ptr)
943{
944 char *msg;
945 for (;;) {
946 int type = use_ssh2_packet_format ?
947 packet_read_poll2(payload_len_ptr):
948 packet_read_poll1(payload_len_ptr);
949
950 if(compat20) {
951 int reason;
952 if (type != 0)
953 DBG(debug("received packet type %d", type));
954 switch(type) {
955 case SSH2_MSG_IGNORE:
956 break;
957 case SSH2_MSG_DEBUG:
958 packet_get_char();
959 msg = packet_get_string(NULL);
960 debug("Remote: %.900s", msg);
961 xfree(msg);
962 msg = packet_get_string(NULL);
963 xfree(msg);
964 break;
965 case SSH2_MSG_DISCONNECT:
966 reason = packet_get_int();
967 msg = packet_get_string(NULL);
968 log("Received disconnect: %d: %.900s", reason, msg);
969 xfree(msg);
970 fatal_cleanup();
971 break;
972 default:
973 return type;
974 break;
975 }
976 } else {
977 switch(type) {
978 case SSH_MSG_IGNORE:
979 break;
980 case SSH_MSG_DEBUG:
981 msg = packet_get_string(NULL);
982 debug("Remote: %.900s", msg);
983 xfree(msg);
984 break;
985 case SSH_MSG_DISCONNECT:
986 msg = packet_get_string(NULL);
987 log("Received disconnect: %.900s", msg);
988 fatal_cleanup();
989 xfree(msg);
990 break;
991 default:
992 if (type != 0)
993 DBG(debug("received packet type %d", type));
994 return type;
995 break;
996 }
997 }
998 }
999}
1000
Damien Miller5428f641999-11-25 11:54:57 +11001001/*
1002 * Buffers the given amount of input characters. This is intended to be used
1003 * together with packet_read_poll.
1004 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001005
1006void
1007packet_process_incoming(const char *buf, unsigned int len)
1008{
Damien Miller95def091999-11-25 00:26:21 +11001009 buffer_append(&input, buf, len);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001010}
1011
1012/* Returns a character from the packet. */
1013
1014unsigned int
1015packet_get_char()
1016{
Damien Miller95def091999-11-25 00:26:21 +11001017 char ch;
1018 buffer_get(&incoming_packet, &ch, 1);
1019 return (unsigned char) ch;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001020}
1021
1022/* Returns an integer from the packet data. */
1023
1024unsigned int
1025packet_get_int()
1026{
Damien Miller95def091999-11-25 00:26:21 +11001027 return buffer_get_int(&incoming_packet);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001028}
1029
Damien Miller5428f641999-11-25 11:54:57 +11001030/*
1031 * Returns an arbitrary precision integer from the packet data. The integer
1032 * must have been initialized before this call.
1033 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001034
1035void
Damien Miller95def091999-11-25 00:26:21 +11001036packet_get_bignum(BIGNUM * value, int *length_ptr)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001037{
Damien Miller95def091999-11-25 00:26:21 +11001038 *length_ptr = buffer_get_bignum(&incoming_packet, value);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001039}
1040
Damien Miller33b13562000-04-04 14:38:59 +10001041void
1042packet_get_bignum2(BIGNUM * value, int *length_ptr)
1043{
1044 *length_ptr = buffer_get_bignum2(&incoming_packet, value);
1045}
1046
1047char *
1048packet_get_raw(int *length_ptr)
1049{
1050 int bytes = buffer_len(&incoming_packet);
1051 if (length_ptr != NULL)
1052 *length_ptr = bytes;
1053 return buffer_ptr(&incoming_packet);
1054}
1055
Damien Miller4af51302000-04-16 11:18:38 +10001056int
1057packet_remaining(void)
1058{
1059 return buffer_len(&incoming_packet);
1060}
1061
Damien Miller5428f641999-11-25 11:54:57 +11001062/*
1063 * Returns a string from the packet data. The string is allocated using
1064 * xmalloc; it is the responsibility of the calling program to free it when
1065 * no longer needed. The length_ptr argument may be NULL, or point to an
1066 * integer into which the length of the string is stored.
1067 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001068
Damien Miller5428f641999-11-25 11:54:57 +11001069char *
Damien Miller95def091999-11-25 00:26:21 +11001070packet_get_string(unsigned int *length_ptr)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001071{
Damien Miller95def091999-11-25 00:26:21 +11001072 return buffer_get_string(&incoming_packet, length_ptr);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001073}
1074
Damien Miller5428f641999-11-25 11:54:57 +11001075/*
1076 * Sends a diagnostic message from the server to the client. This message
1077 * can be sent at any time (but not while constructing another message). The
1078 * message is printed immediately, but only if the client is being executed
1079 * in verbose mode. These messages are primarily intended to ease debugging
1080 * authentication problems. The length of the formatted message must not
1081 * exceed 1024 bytes. This will automatically call packet_write_wait.
1082 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001083
1084void
Damien Miller95def091999-11-25 00:26:21 +11001085packet_send_debug(const char *fmt,...)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001086{
Damien Miller95def091999-11-25 00:26:21 +11001087 char buf[1024];
1088 va_list args;
1089
1090 va_start(args, fmt);
1091 vsnprintf(buf, sizeof(buf), fmt, args);
1092 va_end(args);
1093
Damien Miller7c8af4f2000-05-01 08:24:07 +10001094 if (compat20) {
1095 packet_start(SSH2_MSG_DEBUG);
1096 packet_put_char(0); /* bool: always display */
1097 packet_put_cstring(buf);
1098 packet_put_cstring("");
1099 } else {
1100 packet_start(SSH_MSG_DEBUG);
1101 packet_put_cstring(buf);
1102 }
Damien Miller95def091999-11-25 00:26:21 +11001103 packet_send();
1104 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001105}
1106
Damien Miller5428f641999-11-25 11:54:57 +11001107/*
1108 * Logs the error plus constructs and sends a disconnect packet, closes the
1109 * connection, and exits. This function never returns. The error message
1110 * should not contain a newline. The length of the formatted message must
1111 * not exceed 1024 bytes.
1112 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001113
1114void
Damien Miller95def091999-11-25 00:26:21 +11001115packet_disconnect(const char *fmt,...)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001116{
Damien Miller95def091999-11-25 00:26:21 +11001117 char buf[1024];
1118 va_list args;
1119 static int disconnecting = 0;
1120 if (disconnecting) /* Guard against recursive invocations. */
1121 fatal("packet_disconnect called recursively.");
1122 disconnecting = 1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001123
Damien Miller5428f641999-11-25 11:54:57 +11001124 /*
1125 * Format the message. Note that the caller must make sure the
1126 * message is of limited size.
1127 */
Damien Miller95def091999-11-25 00:26:21 +11001128 va_start(args, fmt);
1129 vsnprintf(buf, sizeof(buf), fmt, args);
1130 va_end(args);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001131
Damien Miller95def091999-11-25 00:26:21 +11001132 /* Send the disconnect message to the other side, and wait for it to get sent. */
Damien Miller33b13562000-04-04 14:38:59 +10001133 if (compat20) {
1134 packet_start(SSH2_MSG_DISCONNECT);
1135 packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR);
1136 packet_put_cstring(buf);
1137 packet_put_cstring("");
1138 } else {
1139 packet_start(SSH_MSG_DISCONNECT);
1140 packet_put_string(buf, strlen(buf));
1141 }
Damien Miller95def091999-11-25 00:26:21 +11001142 packet_send();
1143 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001144
Damien Miller95def091999-11-25 00:26:21 +11001145 /* Stop listening for connections. */
1146 channel_stop_listening();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001147
Damien Miller95def091999-11-25 00:26:21 +11001148 /* Close the connection. */
1149 packet_close();
1150
1151 /* Display the error locally and exit. */
Damien Milleraae6c611999-12-06 11:47:28 +11001152 log("Disconnecting: %.100s", buf);
1153 fatal_cleanup();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001154}
1155
Damien Miller5428f641999-11-25 11:54:57 +11001156/* Checks if there is any buffered output, and tries to write some of the output. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001157
1158void
1159packet_write_poll()
1160{
Damien Miller95def091999-11-25 00:26:21 +11001161 int len = buffer_len(&output);
1162 if (len > 0) {
1163 len = write(connection_out, buffer_ptr(&output), len);
1164 if (len <= 0) {
1165 if (errno == EAGAIN)
1166 return;
1167 else
1168 fatal("Write failed: %.100s", strerror(errno));
1169 }
1170 buffer_consume(&output, len);
1171 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001172}
1173
Damien Miller5428f641999-11-25 11:54:57 +11001174/*
1175 * Calls packet_write_poll repeatedly until all pending output data has been
1176 * written.
1177 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001178
1179void
1180packet_write_wait()
1181{
Damien Miller95def091999-11-25 00:26:21 +11001182 packet_write_poll();
1183 while (packet_have_data_to_write()) {
1184 fd_set set;
1185 FD_ZERO(&set);
1186 FD_SET(connection_out, &set);
1187 select(connection_out + 1, NULL, &set, NULL, NULL);
1188 packet_write_poll();
1189 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001190}
1191
1192/* Returns true if there is buffered data to write to the connection. */
1193
1194int
1195packet_have_data_to_write()
1196{
Damien Miller95def091999-11-25 00:26:21 +11001197 return buffer_len(&output) != 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001198}
1199
1200/* Returns true if there is not too much data to write to the connection. */
1201
1202int
1203packet_not_very_much_data_to_write()
1204{
Damien Miller95def091999-11-25 00:26:21 +11001205 if (interactive_mode)
1206 return buffer_len(&output) < 16384;
1207 else
1208 return buffer_len(&output) < 128 * 1024;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001209}
1210
1211/* Informs that the current session is interactive. Sets IP flags for that. */
1212
1213void
1214packet_set_interactive(int interactive, int keepalives)
1215{
Damien Miller95def091999-11-25 00:26:21 +11001216 int on = 1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001217
Damien Miller95def091999-11-25 00:26:21 +11001218 /* Record that we are in interactive mode. */
1219 interactive_mode = interactive;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001220
Damien Miller34132e52000-01-14 15:45:46 +11001221 /* Only set socket options if using a socket. */
1222 if (!packet_connection_is_on_socket())
Damien Miller95def091999-11-25 00:26:21 +11001223 return;
Damien Miller95def091999-11-25 00:26:21 +11001224 if (keepalives) {
1225 /* Set keepalives if requested. */
1226 if (setsockopt(connection_in, SOL_SOCKET, SO_KEEPALIVE, (void *) &on,
Damien Miller34132e52000-01-14 15:45:46 +11001227 sizeof(on)) < 0)
Damien Miller95def091999-11-25 00:26:21 +11001228 error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1229 }
Damien Miller34132e52000-01-14 15:45:46 +11001230 /*
1231 * IPTOS_LOWDELAY, TCP_NODELAY and IPTOS_THROUGHPUT are IPv4 only
1232 */
1233 if (!packet_connection_is_ipv4())
1234 return;
Damien Miller95def091999-11-25 00:26:21 +11001235 if (interactive) {
Damien Miller5428f641999-11-25 11:54:57 +11001236 /*
1237 * Set IP options for an interactive connection. Use
1238 * IPTOS_LOWDELAY and TCP_NODELAY.
1239 */
Damien Miller2ae714f2000-07-11 09:29:50 +10001240#if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN)
Damien Miller95def091999-11-25 00:26:21 +11001241 int lowdelay = IPTOS_LOWDELAY;
1242 if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &lowdelay,
Damien Miller34132e52000-01-14 15:45:46 +11001243 sizeof(lowdelay)) < 0)
Damien Miller95def091999-11-25 00:26:21 +11001244 error("setsockopt IPTOS_LOWDELAY: %.100s", strerror(errno));
Damien Miller615f9392000-05-17 22:53:33 +10001245#endif
Damien Miller95def091999-11-25 00:26:21 +11001246 if (setsockopt(connection_in, IPPROTO_TCP, TCP_NODELAY, (void *) &on,
Damien Miller34132e52000-01-14 15:45:46 +11001247 sizeof(on)) < 0)
Damien Miller95def091999-11-25 00:26:21 +11001248 error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
1249 } else {
Damien Miller5428f641999-11-25 11:54:57 +11001250 /*
1251 * Set IP options for a non-interactive connection. Use
1252 * IPTOS_THROUGHPUT.
1253 */
Damien Miller2ae714f2000-07-11 09:29:50 +10001254#if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN)
Damien Miller95def091999-11-25 00:26:21 +11001255 int throughput = IPTOS_THROUGHPUT;
1256 if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &throughput,
Damien Miller34132e52000-01-14 15:45:46 +11001257 sizeof(throughput)) < 0)
Damien Miller95def091999-11-25 00:26:21 +11001258 error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno));
Damien Miller615f9392000-05-17 22:53:33 +10001259#endif
Damien Miller95def091999-11-25 00:26:21 +11001260 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001261}
1262
1263/* Returns true if the current connection is interactive. */
1264
1265int
1266packet_is_interactive()
1267{
Damien Miller95def091999-11-25 00:26:21 +11001268 return interactive_mode;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001269}
Damien Miller6162d121999-11-21 13:23:52 +11001270
1271int
1272packet_set_maxsize(int s)
1273{
Damien Miller95def091999-11-25 00:26:21 +11001274 static int called = 0;
1275 if (called) {
Damien Miller33b13562000-04-04 14:38:59 +10001276 log("packet_set_maxsize: called twice: old %d new %d",
1277 max_packet_size, s);
Damien Miller95def091999-11-25 00:26:21 +11001278 return -1;
1279 }
1280 if (s < 4 * 1024 || s > 1024 * 1024) {
1281 log("packet_set_maxsize: bad size %d", s);
1282 return -1;
1283 }
1284 log("packet_set_maxsize: setting to %d", s);
1285 max_packet_size = s;
1286 return s;
Damien Miller6162d121999-11-21 13:23:52 +11001287}