blob: 32d797122360729bfe811c212b65b9914a010f48 [file] [log] [blame]
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001/*
Damien Miller95def091999-11-25 00:26:21 +11002 * Author: Tatu Ylonen <ylo@cs.hut.fi>
Damien Miller95def091999-11-25 00:26:21 +11003 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4 * All rights reserved
Damien Miller95def091999-11-25 00:26:21 +11005 * This file contains code implementing the packet protocol and communication
6 * with the other side. This same code is used both on client and server side.
Damien Miller33b13562000-04-04 14:38:59 +10007 *
Damien Millere4340be2000-09-16 13:29:08 +11008 * As far as I am concerned, the code I have written for this software
9 * can be used freely for any purpose. Any derived versions of this
10 * software must be clearly marked as such, and if the derived work is
11 * incompatible with the protocol description in the RFC file, it must be
12 * called by a name other than "ssh" or "Secure Shell".
Damien Miller33b13562000-04-04 14:38:59 +100013 *
Damien Millere4340be2000-09-16 13:29:08 +110014 *
15 * SSH2 packet format added by Markus Friedl.
Ben Lindstrom44697232001-07-04 03:32:30 +000016 * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
Damien Millere4340be2000-09-16 13:29:08 +110017 *
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions
20 * are met:
21 * 1. Redistributions of source code must retain the above copyright
22 * notice, this list of conditions and the following disclaimer.
23 * 2. Redistributions in binary form must reproduce the above copyright
24 * notice, this list of conditions and the following disclaimer in the
25 * documentation and/or other materials provided with the distribution.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
28 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
29 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
30 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
31 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
32 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
33 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
34 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
35 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
36 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
Damien Miller95def091999-11-25 00:26:21 +110037 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100038
39#include "includes.h"
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +000040RCSID("$OpenBSD: packet.c,v 1.74 2001/12/05 10:06:12 deraadt Exp $");
Damien Millerd4a8b7e1999-10-27 13:42:43 +100041
42#include "xmalloc.h"
43#include "buffer.h"
44#include "packet.h"
45#include "bufaux.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100046#include "crc32.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100047#include "getput.h"
48
49#include "compress.h"
50#include "deattack.h"
Ben Lindstromc7637672001-06-09 00:36:26 +000051#include "channels.h"
Damien Millerd4a8b7e1999-10-27 13:42:43 +100052
Damien Miller33b13562000-04-04 14:38:59 +100053#include "compat.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000054#include "ssh1.h"
Damien Miller33b13562000-04-04 14:38:59 +100055#include "ssh2.h"
56
Damien Miller874d77b2000-10-14 16:23:11 +110057#include "cipher.h"
Damien Miller33b13562000-04-04 14:38:59 +100058#include "kex.h"
Ben Lindstrom06b33aa2001-02-15 03:01:59 +000059#include "mac.h"
Ben Lindstrom226cfa02001-01-22 05:34:40 +000060#include "log.h"
61#include "canohost.h"
Damien Miller33b13562000-04-04 14:38:59 +100062
63#ifdef PACKET_DEBUG
64#define DBG(x) x
65#else
66#define DBG(x)
67#endif
68
Damien Miller5428f641999-11-25 11:54:57 +110069/*
70 * This variable contains the file descriptors used for communicating with
71 * the other side. connection_in is used for reading; connection_out for
72 * writing. These can be the same descriptor, in which case it is assumed to
73 * be a socket.
74 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100075static int connection_in = -1;
76static int connection_out = -1;
77
Damien Millerd4a8b7e1999-10-27 13:42:43 +100078/* Protocol flags for the remote side. */
Ben Lindstrom46c16222000-12-22 01:43:59 +000079static u_int remote_protocol_flags = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +100080
81/* Encryption context for receiving data. This is only used for decryption. */
82static CipherContext receive_context;
Damien Miller95def091999-11-25 00:26:21 +110083
84/* Encryption context for sending data. This is only used for encryption. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +100085static CipherContext send_context;
86
87/* Buffer for raw input data from the socket. */
88static Buffer input;
89
90/* Buffer for raw output data going to the socket. */
91static Buffer output;
92
93/* Buffer for the partial outgoing packet being constructed. */
94static Buffer outgoing_packet;
95
96/* Buffer for the incoming packet currently being processed. */
97static Buffer incoming_packet;
98
99/* Scratch buffer for packet compression/decompression. */
100static Buffer compression_buffer;
Ben Lindstromfb50cdf2001-04-05 23:20:46 +0000101static int compression_buffer_ready = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000102
103/* Flag indicating whether packet compression/decompression is enabled. */
104static int packet_compression = 0;
105
Damien Miller6162d121999-11-21 13:23:52 +1100106/* default maximum packet size */
107int max_packet_size = 32768;
108
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000109/* Flag indicating whether this module has been initialized. */
110static int initialized = 0;
111
112/* Set to true if the connection is interactive. */
113static int interactive_mode = 0;
114
Damien Miller33b13562000-04-04 14:38:59 +1000115/* Session key information for Encryption and MAC */
Ben Lindstrom2d90e002001-04-04 02:00:54 +0000116Newkeys *newkeys[MODE_MAX];
Damien Miller33b13562000-04-04 14:38:59 +1000117
Damien Miller9f643902001-11-12 11:02:52 +1100118/* roundup current message to extra_pad bytes */
119static u_char extra_pad = 0;
120
Damien Miller5428f641999-11-25 11:54:57 +1100121/*
122 * Sets the descriptors used for communication. Disables encryption until
123 * packet_set_encryption_key is called.
124 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000125void
126packet_set_connection(int fd_in, int fd_out)
127{
Damien Miller874d77b2000-10-14 16:23:11 +1100128 Cipher *none = cipher_by_name("none");
129 if (none == NULL)
130 fatal("packet_set_connection: cannot load cipher 'none'");
Damien Miller95def091999-11-25 00:26:21 +1100131 connection_in = fd_in;
132 connection_out = fd_out;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000133 cipher_init(&send_context, none, (u_char *) "", 0, NULL, 0);
134 cipher_init(&receive_context, none, (u_char *) "", 0, NULL, 0);
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000135 newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL;
Damien Miller95def091999-11-25 00:26:21 +1100136 if (!initialized) {
137 initialized = 1;
138 buffer_init(&input);
139 buffer_init(&output);
140 buffer_init(&outgoing_packet);
141 buffer_init(&incoming_packet);
142 }
143 /* Kludge: arrange the close function to be called from fatal(). */
144 fatal_add_cleanup((void (*) (void *)) packet_close, NULL);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000145}
146
Damien Miller34132e52000-01-14 15:45:46 +1100147/* Returns 1 if remote host is connected via socket, 0 if not. */
148
149int
Ben Lindstrom3c36bb22001-12-06 17:55:26 +0000150packet_connection_is_on_socket(void)
Damien Miller34132e52000-01-14 15:45:46 +1100151{
152 struct sockaddr_storage from, to;
153 socklen_t fromlen, tolen;
154
155 /* filedescriptors in and out are the same, so it's a socket */
156 if (connection_in == connection_out)
157 return 1;
158 fromlen = sizeof(from);
159 memset(&from, 0, sizeof(from));
Damien Millerf052aaf2000-01-22 19:47:21 +1100160 if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0)
Damien Miller34132e52000-01-14 15:45:46 +1100161 return 0;
162 tolen = sizeof(to);
163 memset(&to, 0, sizeof(to));
Damien Millerf052aaf2000-01-22 19:47:21 +1100164 if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0)
Damien Miller34132e52000-01-14 15:45:46 +1100165 return 0;
166 if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
167 return 0;
168 if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
169 return 0;
170 return 1;
171}
172
173/* returns 1 if connection is via ipv4 */
174
175int
Ben Lindstrom3c36bb22001-12-06 17:55:26 +0000176packet_connection_is_ipv4(void)
Damien Miller34132e52000-01-14 15:45:46 +1100177{
178 struct sockaddr_storage to;
Damien Miller6fe375d2000-01-23 09:38:00 +1100179 socklen_t tolen = sizeof(to);
Damien Miller34132e52000-01-14 15:45:46 +1100180
181 memset(&to, 0, sizeof(to));
182 if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0)
183 return 0;
184 if (to.ss_family != AF_INET)
185 return 0;
186 return 1;
187}
188
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000189/* Sets the connection into non-blocking mode. */
190
191void
Ben Lindstrom3c36bb22001-12-06 17:55:26 +0000192packet_set_nonblocking(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000193{
Damien Miller95def091999-11-25 00:26:21 +1100194 /* Set the socket into non-blocking mode. */
195 if (fcntl(connection_in, F_SETFL, O_NONBLOCK) < 0)
196 error("fcntl O_NONBLOCK: %.100s", strerror(errno));
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000197
Damien Miller95def091999-11-25 00:26:21 +1100198 if (connection_out != connection_in) {
199 if (fcntl(connection_out, F_SETFL, O_NONBLOCK) < 0)
200 error("fcntl O_NONBLOCK: %.100s", strerror(errno));
201 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000202}
203
204/* Returns the socket used for reading. */
205
206int
Ben Lindstrom3c36bb22001-12-06 17:55:26 +0000207packet_get_connection_in(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000208{
Damien Miller95def091999-11-25 00:26:21 +1100209 return connection_in;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000210}
211
212/* Returns the descriptor used for writing. */
213
214int
Ben Lindstrom3c36bb22001-12-06 17:55:26 +0000215packet_get_connection_out(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000216{
Damien Miller95def091999-11-25 00:26:21 +1100217 return connection_out;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000218}
219
220/* Closes the connection and clears and frees internal data structures. */
221
222void
Ben Lindstrom3c36bb22001-12-06 17:55:26 +0000223packet_close(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000224{
Damien Miller95def091999-11-25 00:26:21 +1100225 if (!initialized)
226 return;
227 initialized = 0;
228 if (connection_in == connection_out) {
229 shutdown(connection_out, SHUT_RDWR);
230 close(connection_out);
231 } else {
232 close(connection_in);
233 close(connection_out);
234 }
235 buffer_free(&input);
236 buffer_free(&output);
237 buffer_free(&outgoing_packet);
238 buffer_free(&incoming_packet);
Ben Lindstromfb50cdf2001-04-05 23:20:46 +0000239 if (compression_buffer_ready) {
Damien Miller95def091999-11-25 00:26:21 +1100240 buffer_free(&compression_buffer);
241 buffer_compress_uninit();
242 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000243}
244
245/* Sets remote side protocol flags. */
246
247void
Ben Lindstrom46c16222000-12-22 01:43:59 +0000248packet_set_protocol_flags(u_int protocol_flags)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000249{
Damien Miller95def091999-11-25 00:26:21 +1100250 remote_protocol_flags = protocol_flags;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000251}
252
253/* Returns the remote protocol flags set earlier by the above function. */
254
Ben Lindstrom46c16222000-12-22 01:43:59 +0000255u_int
Ben Lindstrom3c36bb22001-12-06 17:55:26 +0000256packet_get_protocol_flags(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000257{
Damien Miller95def091999-11-25 00:26:21 +1100258 return remote_protocol_flags;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000259}
260
Damien Miller5428f641999-11-25 11:54:57 +1100261/*
262 * Starts packet compression from the next packet on in both directions.
263 * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
264 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000265
Ben Lindstrombba81212001-06-25 05:01:22 +0000266static void
267packet_init_compression(void)
Ben Lindstromfb50cdf2001-04-05 23:20:46 +0000268{
269 if (compression_buffer_ready == 1)
270 return;
271 compression_buffer_ready = 1;
272 buffer_init(&compression_buffer);
273}
274
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000275void
276packet_start_compression(int level)
277{
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000278 if (packet_compression && !compat20)
Damien Miller95def091999-11-25 00:26:21 +1100279 fatal("Compression already enabled.");
280 packet_compression = 1;
Ben Lindstromfb50cdf2001-04-05 23:20:46 +0000281 packet_init_compression();
282 buffer_compress_init_send(level);
283 buffer_compress_init_recv();
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000284}
285
Damien Miller5428f641999-11-25 11:54:57 +1100286/*
Damien Miller5428f641999-11-25 11:54:57 +1100287 * Causes any further packets to be encrypted using the given key. The same
288 * key is used for both sending and reception. However, both directions are
289 * encrypted independently of each other.
290 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000291void
Ben Lindstrom46c16222000-12-22 01:43:59 +0000292packet_set_encryption_key(const u_char *key, u_int keylen,
Damien Miller874d77b2000-10-14 16:23:11 +1100293 int number)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000294{
Damien Miller874d77b2000-10-14 16:23:11 +1100295 Cipher *cipher = cipher_by_number(number);
296 if (cipher == NULL)
297 fatal("packet_set_encryption_key: unknown cipher number %d", number);
Damien Miller33b13562000-04-04 14:38:59 +1000298 if (keylen < 20)
Damien Miller874d77b2000-10-14 16:23:11 +1100299 fatal("packet_set_encryption_key: keylen too small: %d", keylen);
300 cipher_init(&receive_context, cipher, key, keylen, NULL, 0);
301 cipher_init(&send_context, cipher, key, keylen, NULL, 0);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000302}
303
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000304/* Start constructing a packet to send. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000305void
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000306packet_start(u_char type)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000307{
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000308 u_char buf[9];
309 int len;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000310
Ben Lindstrom204e4882001-03-05 06:47:00 +0000311 DBG(debug("packet_start[%d]", type));
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000312 len = compat20 ? 6 : 9;
313 memset(buf, 0, len - 1);
314 buf[len - 1] = type;
315 buffer_clear(&outgoing_packet);
316 buffer_append(&outgoing_packet, buf, len);
Damien Miller33b13562000-04-04 14:38:59 +1000317}
318
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000319/* Append payload. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000320void
321packet_put_char(int value)
322{
Damien Miller95def091999-11-25 00:26:21 +1100323 char ch = value;
324 buffer_append(&outgoing_packet, &ch, 1);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000325}
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000326void
Ben Lindstrom46c16222000-12-22 01:43:59 +0000327packet_put_int(u_int value)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000328{
Damien Miller95def091999-11-25 00:26:21 +1100329 buffer_put_int(&outgoing_packet, value);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000330}
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000331void
Ben Lindstrom46c16222000-12-22 01:43:59 +0000332packet_put_string(const char *buf, u_int len)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000333{
Damien Miller95def091999-11-25 00:26:21 +1100334 buffer_put_string(&outgoing_packet, buf, len);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000335}
Damien Miller33b13562000-04-04 14:38:59 +1000336void
337packet_put_cstring(const char *str)
338{
Ben Lindstrom664408d2001-06-09 01:42:01 +0000339 buffer_put_cstring(&outgoing_packet, str);
Damien Miller33b13562000-04-04 14:38:59 +1000340}
Damien Miller33b13562000-04-04 14:38:59 +1000341void
Ben Lindstrom46c16222000-12-22 01:43:59 +0000342packet_put_raw(const char *buf, u_int len)
Damien Miller33b13562000-04-04 14:38:59 +1000343{
344 buffer_append(&outgoing_packet, buf, len);
345}
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000346void
Damien Miller95def091999-11-25 00:26:21 +1100347packet_put_bignum(BIGNUM * value)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000348{
Damien Miller95def091999-11-25 00:26:21 +1100349 buffer_put_bignum(&outgoing_packet, value);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000350}
Damien Miller33b13562000-04-04 14:38:59 +1000351void
352packet_put_bignum2(BIGNUM * value)
353{
354 buffer_put_bignum2(&outgoing_packet, value);
355}
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000356
Damien Miller5428f641999-11-25 11:54:57 +1100357/*
358 * Finalizes and sends the packet. If the encryption key has been set,
359 * encrypts the packet before sending.
360 */
Damien Miller95def091999-11-25 00:26:21 +1100361
Ben Lindstrombba81212001-06-25 05:01:22 +0000362static void
Ben Lindstrom31ca54a2001-02-09 02:11:24 +0000363packet_send1(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000364{
Damien Miller95def091999-11-25 00:26:21 +1100365 char buf[8], *cp;
366 int i, padding, len;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000367 u_int checksum;
Damien Miller95def091999-11-25 00:26:21 +1100368 u_int32_t rand = 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000369
Damien Miller5428f641999-11-25 11:54:57 +1100370 /*
371 * If using packet compression, compress the payload of the outgoing
372 * packet.
373 */
Damien Miller95def091999-11-25 00:26:21 +1100374 if (packet_compression) {
375 buffer_clear(&compression_buffer);
376 /* Skip padding. */
377 buffer_consume(&outgoing_packet, 8);
378 /* padding */
379 buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8);
380 buffer_compress(&outgoing_packet, &compression_buffer);
381 buffer_clear(&outgoing_packet);
382 buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
383 buffer_len(&compression_buffer));
384 }
385 /* Compute packet length without padding (add checksum, remove padding). */
386 len = buffer_len(&outgoing_packet) + 4 - 8;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000387
Damien Millere247cc42000-05-07 12:03:14 +1000388 /* Insert padding. Initialized to zero in packet_start1() */
Damien Miller95def091999-11-25 00:26:21 +1100389 padding = 8 - len % 8;
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000390 if (send_context.cipher->number != SSH_CIPHER_NONE) {
Damien Miller95def091999-11-25 00:26:21 +1100391 cp = buffer_ptr(&outgoing_packet);
392 for (i = 0; i < padding; i++) {
393 if (i % 4 == 0)
394 rand = arc4random();
395 cp[7 - i] = rand & 0xff;
396 rand >>= 8;
397 }
398 }
399 buffer_consume(&outgoing_packet, 8 - padding);
400
401 /* Add check bytes. */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000402 checksum = ssh_crc32((u_char *) buffer_ptr(&outgoing_packet),
Damien Millerad833b32000-08-23 10:46:23 +1000403 buffer_len(&outgoing_packet));
Damien Miller95def091999-11-25 00:26:21 +1100404 PUT_32BIT(buf, checksum);
405 buffer_append(&outgoing_packet, buf, 4);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000406
407#ifdef PACKET_DEBUG
Damien Miller95def091999-11-25 00:26:21 +1100408 fprintf(stderr, "packet_send plain: ");
409 buffer_dump(&outgoing_packet);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000410#endif
411
Damien Miller95def091999-11-25 00:26:21 +1100412 /* Append to output. */
413 PUT_32BIT(buf, len);
414 buffer_append(&output, buf, 4);
415 buffer_append_space(&output, &cp, buffer_len(&outgoing_packet));
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000416 cipher_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),
Damien Miller95def091999-11-25 00:26:21 +1100417 buffer_len(&outgoing_packet));
418
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000419#ifdef PACKET_DEBUG
Damien Miller95def091999-11-25 00:26:21 +1100420 fprintf(stderr, "encrypted: ");
421 buffer_dump(&output);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000422#endif
423
Damien Miller95def091999-11-25 00:26:21 +1100424 buffer_clear(&outgoing_packet);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000425
Damien Miller5428f641999-11-25 11:54:57 +1100426 /*
427 * Note that the packet is now only buffered in output. It won\'t be
428 * actually sent until packet_write_wait or packet_write_poll is
429 * called.
430 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000431}
432
Ben Lindstrombba81212001-06-25 05:01:22 +0000433static void
Ben Lindstrom2d90e002001-04-04 02:00:54 +0000434set_newkeys(int mode)
435{
436 Enc *enc;
437 Mac *mac;
438 Comp *comp;
439 CipherContext *cc;
440
441 debug("newkeys: mode %d", mode);
442
443 cc = (mode == MODE_OUT) ? &send_context : &receive_context;
444 if (newkeys[mode] != NULL) {
445 debug("newkeys: rekeying");
Ben Lindstrom238abf62001-04-04 17:52:53 +0000446 /* todo: free old keys, reset compression/cipher-ctxt; */
Ben Lindstrom5ba23b32001-04-05 02:05:21 +0000447 memset(cc, 0, sizeof(*cc));
448 enc = &newkeys[mode]->enc;
449 mac = &newkeys[mode]->mac;
450 comp = &newkeys[mode]->comp;
Ben Lindstroma3700052001-04-05 23:26:32 +0000451 memset(mac->key, 0, mac->key_len);
Ben Lindstrom5ba23b32001-04-05 02:05:21 +0000452 xfree(enc->name);
453 xfree(enc->iv);
454 xfree(enc->key);
455 xfree(mac->name);
456 xfree(mac->key);
457 xfree(comp->name);
Ben Lindstrom238abf62001-04-04 17:52:53 +0000458 xfree(newkeys[mode]);
Ben Lindstrom2d90e002001-04-04 02:00:54 +0000459 }
460 newkeys[mode] = kex_get_newkeys(mode);
461 if (newkeys[mode] == NULL)
462 fatal("newkeys: no keys for mode %d", mode);
463 enc = &newkeys[mode]->enc;
464 mac = &newkeys[mode]->mac;
465 comp = &newkeys[mode]->comp;
466 if (mac->md != NULL)
467 mac->enabled = 1;
468 DBG(debug("cipher_init_context: %d", mode));
469 cipher_init(cc, enc->cipher, enc->key, enc->cipher->key_len,
470 enc->iv, enc->cipher->block_size);
Ben Lindstrom5ba23b32001-04-05 02:05:21 +0000471 memset(enc->iv, 0, enc->cipher->block_size);
472 memset(enc->key, 0, enc->cipher->key_len);
Ben Lindstrom2d90e002001-04-04 02:00:54 +0000473 if (comp->type != 0 && comp->enabled == 0) {
Ben Lindstromfb50cdf2001-04-05 23:20:46 +0000474 packet_init_compression();
475 if (mode == MODE_OUT)
476 buffer_compress_init_send(6);
477 else
478 buffer_compress_init_recv();
Ben Lindstrom2d90e002001-04-04 02:00:54 +0000479 comp->enabled = 1;
Ben Lindstrom2d90e002001-04-04 02:00:54 +0000480 }
481}
482
Damien Miller5428f641999-11-25 11:54:57 +1100483/*
Damien Miller33b13562000-04-04 14:38:59 +1000484 * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
485 */
Ben Lindstrombba81212001-06-25 05:01:22 +0000486static void
Ben Lindstrom31ca54a2001-02-09 02:11:24 +0000487packet_send2(void)
Damien Miller33b13562000-04-04 14:38:59 +1000488{
Ben Lindstrom06b33aa2001-02-15 03:01:59 +0000489 static u_int32_t seqnr = 0;
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000490 u_char type, *ucp, *macbuf = NULL;
Damien Miller9f643902001-11-12 11:02:52 +1100491 u_char padlen, pad;
Damien Miller33b13562000-04-04 14:38:59 +1000492 char *cp;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000493 u_int packet_length = 0;
Damien Miller9f643902001-11-12 11:02:52 +1100494 u_int i, len;
Damien Miller33b13562000-04-04 14:38:59 +1000495 u_int32_t rand = 0;
Damien Miller33b13562000-04-04 14:38:59 +1000496 Enc *enc = NULL;
497 Mac *mac = NULL;
498 Comp *comp = NULL;
499 int block_size;
500
Ben Lindstrom2d90e002001-04-04 02:00:54 +0000501 if (newkeys[MODE_OUT] != NULL) {
502 enc = &newkeys[MODE_OUT]->enc;
503 mac = &newkeys[MODE_OUT]->mac;
504 comp = &newkeys[MODE_OUT]->comp;
Damien Miller33b13562000-04-04 14:38:59 +1000505 }
Damien Miller874d77b2000-10-14 16:23:11 +1100506 block_size = enc ? enc->cipher->block_size : 8;
Damien Miller33b13562000-04-04 14:38:59 +1000507
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000508 ucp = (u_char *) buffer_ptr(&outgoing_packet);
509 type = ucp[5];
Damien Miller33b13562000-04-04 14:38:59 +1000510
511#ifdef PACKET_DEBUG
512 fprintf(stderr, "plain: ");
513 buffer_dump(&outgoing_packet);
514#endif
515
516 if (comp && comp->enabled) {
517 len = buffer_len(&outgoing_packet);
518 /* skip header, compress only payload */
519 buffer_consume(&outgoing_packet, 5);
520 buffer_clear(&compression_buffer);
521 buffer_compress(&outgoing_packet, &compression_buffer);
522 buffer_clear(&outgoing_packet);
523 buffer_append(&outgoing_packet, "\0\0\0\0\0", 5);
524 buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
525 buffer_len(&compression_buffer));
526 DBG(debug("compression: raw %d compressed %d", len,
527 buffer_len(&outgoing_packet)));
528 }
529
530 /* sizeof (packet_len + pad_len + payload) */
531 len = buffer_len(&outgoing_packet);
532
533 /*
534 * calc size of padding, alloc space, get random data,
535 * minimum padding is 4 bytes
536 */
537 padlen = block_size - (len % block_size);
538 if (padlen < 4)
539 padlen += block_size;
Damien Miller9f643902001-11-12 11:02:52 +1100540 if (extra_pad) {
541 /* will wrap if extra_pad+padlen > 255 */
542 extra_pad = roundup(extra_pad, block_size);
543 pad = extra_pad - ((len + padlen) % extra_pad);
544 debug("packet_send2: adding %d (len %d padlen %d extra_pad %d)",
545 pad, len, padlen, extra_pad);
546 padlen += pad;
547 extra_pad = 0;
548 }
Damien Miller33b13562000-04-04 14:38:59 +1000549 buffer_append_space(&outgoing_packet, &cp, padlen);
Damien Miller874d77b2000-10-14 16:23:11 +1100550 if (enc && enc->cipher->number != SSH_CIPHER_NONE) {
Damien Millere247cc42000-05-07 12:03:14 +1000551 /* random padding */
Damien Miller33b13562000-04-04 14:38:59 +1000552 for (i = 0; i < padlen; i++) {
553 if (i % 4 == 0)
554 rand = arc4random();
555 cp[i] = rand & 0xff;
Ben Lindstrom6a5cde02001-03-05 06:07:00 +0000556 rand >>= 8;
Damien Miller33b13562000-04-04 14:38:59 +1000557 }
Damien Millere247cc42000-05-07 12:03:14 +1000558 } else {
559 /* clear padding */
560 memset(cp, 0, padlen);
Damien Miller33b13562000-04-04 14:38:59 +1000561 }
562 /* packet_length includes payload, padding and padding length field */
563 packet_length = buffer_len(&outgoing_packet) - 4;
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000564 ucp = (u_char *)buffer_ptr(&outgoing_packet);
565 PUT_32BIT(ucp, packet_length);
566 ucp[4] = padlen;
Damien Miller33b13562000-04-04 14:38:59 +1000567 DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen));
568
569 /* compute MAC over seqnr and packet(length fields, payload, padding) */
570 if (mac && mac->enabled) {
Ben Lindstrom06b33aa2001-02-15 03:01:59 +0000571 macbuf = mac_compute(mac, seqnr,
Ben Lindstrom46c16222000-12-22 01:43:59 +0000572 (u_char *) buffer_ptr(&outgoing_packet),
Ben Lindstrom06b33aa2001-02-15 03:01:59 +0000573 buffer_len(&outgoing_packet));
Damien Miller874d77b2000-10-14 16:23:11 +1100574 DBG(debug("done calc MAC out #%d", seqnr));
Damien Miller33b13562000-04-04 14:38:59 +1000575 }
576 /* encrypt packet and append to output buffer. */
577 buffer_append_space(&output, &cp, buffer_len(&outgoing_packet));
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000578 cipher_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),
Damien Miller33b13562000-04-04 14:38:59 +1000579 buffer_len(&outgoing_packet));
580 /* append unencrypted MAC */
581 if (mac && mac->enabled)
582 buffer_append(&output, (char *)macbuf, mac->mac_len);
583#ifdef PACKET_DEBUG
584 fprintf(stderr, "encrypted: ");
585 buffer_dump(&output);
586#endif
Damien Miller4af51302000-04-16 11:18:38 +1000587 /* increment sequence number for outgoing packets */
588 if (++seqnr == 0)
589 log("outgoing seqnr wraps around");
Damien Miller33b13562000-04-04 14:38:59 +1000590 buffer_clear(&outgoing_packet);
591
Ben Lindstrom2d90e002001-04-04 02:00:54 +0000592 if (type == SSH2_MSG_NEWKEYS)
593 set_newkeys(MODE_OUT);
Damien Miller33b13562000-04-04 14:38:59 +1000594}
595
596void
Ben Lindstrom3c36bb22001-12-06 17:55:26 +0000597packet_send(void)
Damien Miller33b13562000-04-04 14:38:59 +1000598{
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000599 if (compat20)
Damien Miller33b13562000-04-04 14:38:59 +1000600 packet_send2();
601 else
602 packet_send1();
603 DBG(debug("packet_send done"));
604}
605
Damien Miller33b13562000-04-04 14:38:59 +1000606/*
Damien Miller5428f641999-11-25 11:54:57 +1100607 * Waits until a packet has been received, and returns its type. Note that
608 * no other data is processed until this returns, so this function should not
609 * be used during the interactive session.
610 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000611
612int
613packet_read(int *payload_len_ptr)
614{
Damien Miller95def091999-11-25 00:26:21 +1100615 int type, len;
Ben Lindstromcb978aa2001-03-05 07:07:49 +0000616 fd_set *setp;
Damien Miller95def091999-11-25 00:26:21 +1100617 char buf[8192];
Damien Miller33b13562000-04-04 14:38:59 +1000618 DBG(debug("packet_read()"));
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000619
Ben Lindstromcb978aa2001-03-05 07:07:49 +0000620 setp = (fd_set *)xmalloc(howmany(connection_in+1, NFDBITS) *
621 sizeof(fd_mask));
622
Damien Miller95def091999-11-25 00:26:21 +1100623 /* Since we are blocking, ensure that all written packets have been sent. */
624 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000625
Damien Miller95def091999-11-25 00:26:21 +1100626 /* Stay in the loop until we have received a complete packet. */
627 for (;;) {
628 /* Try to read a packet from the buffer. */
629 type = packet_read_poll(payload_len_ptr);
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000630 if (!compat20 && (
Damien Millere247cc42000-05-07 12:03:14 +1000631 type == SSH_SMSG_SUCCESS
Damien Miller95def091999-11-25 00:26:21 +1100632 || type == SSH_SMSG_FAILURE
633 || type == SSH_CMSG_EOF
Damien Millere247cc42000-05-07 12:03:14 +1000634 || type == SSH_CMSG_EXIT_CONFIRMATION))
Damien Miller95def091999-11-25 00:26:21 +1100635 packet_integrity_check(*payload_len_ptr, 0, type);
636 /* If we got a packet, return it. */
Ben Lindstromcb978aa2001-03-05 07:07:49 +0000637 if (type != SSH_MSG_NONE) {
638 xfree(setp);
Damien Miller95def091999-11-25 00:26:21 +1100639 return type;
Ben Lindstromcb978aa2001-03-05 07:07:49 +0000640 }
Damien Miller5428f641999-11-25 11:54:57 +1100641 /*
642 * Otherwise, wait for some data to arrive, add it to the
643 * buffer, and try again.
644 */
Ben Lindstromcb978aa2001-03-05 07:07:49 +0000645 memset(setp, 0, howmany(connection_in + 1, NFDBITS) *
646 sizeof(fd_mask));
647 FD_SET(connection_in, setp);
Damien Miller5428f641999-11-25 11:54:57 +1100648
Damien Miller95def091999-11-25 00:26:21 +1100649 /* Wait for some data to arrive. */
Ben Lindstromcb978aa2001-03-05 07:07:49 +0000650 while (select(connection_in + 1, setp, NULL, NULL, NULL) == -1 &&
Ben Lindstromf9452512001-02-15 03:12:08 +0000651 (errno == EAGAIN || errno == EINTR))
652 ;
Damien Miller5428f641999-11-25 11:54:57 +1100653
Damien Miller95def091999-11-25 00:26:21 +1100654 /* Read data from the socket. */
655 len = read(connection_in, buf, sizeof(buf));
Damien Miller5e7c10e1999-12-16 13:18:04 +1100656 if (len == 0) {
657 log("Connection closed by %.200s", get_remote_ipaddr());
658 fatal_cleanup();
659 }
Damien Miller95def091999-11-25 00:26:21 +1100660 if (len < 0)
661 fatal("Read from socket failed: %.100s", strerror(errno));
662 /* Append it to the buffer. */
663 packet_process_incoming(buf, len);
664 }
665 /* NOTREACHED */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000666}
667
Damien Miller5428f641999-11-25 11:54:57 +1100668/*
669 * Waits until a packet has been received, verifies that its type matches
670 * that given, and gives a fatal error and exits if there is a mismatch.
671 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000672
673void
674packet_read_expect(int *payload_len_ptr, int expected_type)
675{
Damien Miller95def091999-11-25 00:26:21 +1100676 int type;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000677
Damien Miller95def091999-11-25 00:26:21 +1100678 type = packet_read(payload_len_ptr);
679 if (type != expected_type)
680 packet_disconnect("Protocol error: expected packet type %d, got %d",
Damien Miller33b13562000-04-04 14:38:59 +1000681 expected_type, type);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000682}
683
684/* Checks if a full packet is available in the data received so far via
Damien Miller95def091999-11-25 00:26:21 +1100685 * packet_process_incoming. If so, reads the packet; otherwise returns
686 * SSH_MSG_NONE. This does not wait for data from the connection.
687 *
688 * SSH_MSG_DISCONNECT is handled specially here. Also,
689 * SSH_MSG_IGNORE messages are skipped by this function and are never returned
690 * to higher levels.
691 *
692 * The returned payload_len does include space consumed by:
693 * Packet length
694 * Padding
695 * Packet type
696 * Check bytes
697 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000698
Ben Lindstrombba81212001-06-25 05:01:22 +0000699static int
Damien Miller33b13562000-04-04 14:38:59 +1000700packet_read_poll1(int *payload_len_ptr)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000701{
Ben Lindstrom46c16222000-12-22 01:43:59 +0000702 u_int len, padded_len;
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000703 u_char *ucp, type;
704 char *cp;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000705 u_int checksum, stored_checksum;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000706
Damien Miller95def091999-11-25 00:26:21 +1100707 /* Check if input size is less than minimum packet size. */
708 if (buffer_len(&input) < 4 + 8)
709 return SSH_MSG_NONE;
710 /* Get length of incoming packet. */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000711 ucp = (u_char *) buffer_ptr(&input);
Damien Miller95def091999-11-25 00:26:21 +1100712 len = GET_32BIT(ucp);
713 if (len < 1 + 2 + 2 || len > 256 * 1024)
714 packet_disconnect("Bad packet length %d.", len);
715 padded_len = (len + 8) & ~7;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000716
Damien Miller95def091999-11-25 00:26:21 +1100717 /* Check if the packet has been entirely received. */
718 if (buffer_len(&input) < 4 + padded_len)
719 return SSH_MSG_NONE;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000720
Damien Miller95def091999-11-25 00:26:21 +1100721 /* The entire packet is in buffer. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000722
Damien Miller95def091999-11-25 00:26:21 +1100723 /* Consume packet length. */
724 buffer_consume(&input, 4);
725
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000726 /*
727 * Cryptographic attack detector for ssh
728 * (C)1998 CORE-SDI, Buenos Aires Argentina
729 * Ariel Futoransky(futo@core-sdi.com)
730 */
731 if (receive_context.cipher->number != SSH_CIPHER_NONE &&
732 detect_attack(buffer_ptr(&input), padded_len, NULL) == DEATTACK_DETECTED)
733 packet_disconnect("crc32 compensation attack: network attack detected");
734
735 /* Decrypt data to incoming_packet. */
Damien Miller95def091999-11-25 00:26:21 +1100736 buffer_clear(&incoming_packet);
737 buffer_append_space(&incoming_packet, &cp, padded_len);
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000738 cipher_decrypt(&receive_context, cp, buffer_ptr(&input), padded_len);
739
Damien Miller95def091999-11-25 00:26:21 +1100740 buffer_consume(&input, padded_len);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000741
742#ifdef PACKET_DEBUG
Damien Miller95def091999-11-25 00:26:21 +1100743 fprintf(stderr, "read_poll plain: ");
744 buffer_dump(&incoming_packet);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000745#endif
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000746
Damien Miller95def091999-11-25 00:26:21 +1100747 /* Compute packet checksum. */
Ben Lindstrom46c16222000-12-22 01:43:59 +0000748 checksum = ssh_crc32((u_char *) buffer_ptr(&incoming_packet),
Damien Miller33b13562000-04-04 14:38:59 +1000749 buffer_len(&incoming_packet) - 4);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000750
Damien Miller95def091999-11-25 00:26:21 +1100751 /* Skip padding. */
752 buffer_consume(&incoming_packet, 8 - len % 8);
Damien Millerfd7c9111999-11-08 16:15:55 +1100753
Damien Miller95def091999-11-25 00:26:21 +1100754 /* Test check bytes. */
Damien Miller95def091999-11-25 00:26:21 +1100755 if (len != buffer_len(&incoming_packet))
756 packet_disconnect("packet_read_poll: len %d != buffer_len %d.",
Damien Miller33b13562000-04-04 14:38:59 +1000757 len, buffer_len(&incoming_packet));
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000758
Ben Lindstrom46c16222000-12-22 01:43:59 +0000759 ucp = (u_char *) buffer_ptr(&incoming_packet) + len - 4;
Damien Miller95def091999-11-25 00:26:21 +1100760 stored_checksum = GET_32BIT(ucp);
761 if (checksum != stored_checksum)
762 packet_disconnect("Corrupted check bytes on input.");
763 buffer_consume_end(&incoming_packet, 4);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000764
Damien Miller95def091999-11-25 00:26:21 +1100765 if (packet_compression) {
766 buffer_clear(&compression_buffer);
767 buffer_uncompress(&incoming_packet, &compression_buffer);
768 buffer_clear(&incoming_packet);
769 buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
Damien Miller33b13562000-04-04 14:38:59 +1000770 buffer_len(&compression_buffer));
Damien Miller95def091999-11-25 00:26:21 +1100771 }
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000772 type = buffer_get_char(&incoming_packet);
Damien Miller95def091999-11-25 00:26:21 +1100773 *payload_len_ptr = buffer_len(&incoming_packet);
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000774 return type;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000775}
Damien Miller95def091999-11-25 00:26:21 +1100776
Ben Lindstrombba81212001-06-25 05:01:22 +0000777static int
Damien Miller33b13562000-04-04 14:38:59 +1000778packet_read_poll2(int *payload_len_ptr)
779{
Ben Lindstrom06b33aa2001-02-15 03:01:59 +0000780 static u_int32_t seqnr = 0;
781 static u_int packet_length = 0;
Ben Lindstrom46c16222000-12-22 01:43:59 +0000782 u_int padlen, need;
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000783 u_char *macbuf, *ucp, type;
Damien Miller33b13562000-04-04 14:38:59 +1000784 char *cp;
Damien Miller33b13562000-04-04 14:38:59 +1000785 int maclen, block_size;
786 Enc *enc = NULL;
787 Mac *mac = NULL;
788 Comp *comp = NULL;
789
Ben Lindstrom2d90e002001-04-04 02:00:54 +0000790 if (newkeys[MODE_IN] != NULL) {
791 enc = &newkeys[MODE_IN]->enc;
792 mac = &newkeys[MODE_IN]->mac;
793 comp = &newkeys[MODE_IN]->comp;
Damien Miller33b13562000-04-04 14:38:59 +1000794 }
795 maclen = mac && mac->enabled ? mac->mac_len : 0;
Damien Miller874d77b2000-10-14 16:23:11 +1100796 block_size = enc ? enc->cipher->block_size : 8;
Damien Miller33b13562000-04-04 14:38:59 +1000797
798 if (packet_length == 0) {
799 /*
800 * check if input size is less than the cipher block size,
801 * decrypt first block and extract length of incoming packet
802 */
803 if (buffer_len(&input) < block_size)
804 return SSH_MSG_NONE;
805 buffer_clear(&incoming_packet);
806 buffer_append_space(&incoming_packet, &cp, block_size);
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000807 cipher_decrypt(&receive_context, cp, buffer_ptr(&input),
Damien Miller33b13562000-04-04 14:38:59 +1000808 block_size);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000809 ucp = (u_char *) buffer_ptr(&incoming_packet);
Damien Miller33b13562000-04-04 14:38:59 +1000810 packet_length = GET_32BIT(ucp);
811 if (packet_length < 1 + 4 || packet_length > 256 * 1024) {
812 buffer_dump(&incoming_packet);
813 packet_disconnect("Bad packet length %d.", packet_length);
814 }
815 DBG(debug("input: packet len %d", packet_length+4));
816 buffer_consume(&input, block_size);
817 }
818 /* we have a partial packet of block_size bytes */
819 need = 4 + packet_length - block_size;
820 DBG(debug("partial packet %d, need %d, maclen %d", block_size,
821 need, maclen));
822 if (need % block_size != 0)
823 fatal("padding error: need %d block %d mod %d",
824 need, block_size, need % block_size);
825 /*
826 * check if the entire packet has been received and
827 * decrypt into incoming_packet
828 */
829 if (buffer_len(&input) < need + maclen)
830 return SSH_MSG_NONE;
831#ifdef PACKET_DEBUG
832 fprintf(stderr, "read_poll enc/full: ");
833 buffer_dump(&input);
834#endif
835 buffer_append_space(&incoming_packet, &cp, need);
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000836 cipher_decrypt(&receive_context, cp, buffer_ptr(&input), need);
Damien Miller33b13562000-04-04 14:38:59 +1000837 buffer_consume(&input, need);
838 /*
839 * compute MAC over seqnr and packet,
840 * increment sequence number for incoming packet
841 */
Damien Miller4af51302000-04-16 11:18:38 +1000842 if (mac && mac->enabled) {
Ben Lindstrom06b33aa2001-02-15 03:01:59 +0000843 macbuf = mac_compute(mac, seqnr,
Ben Lindstrom46c16222000-12-22 01:43:59 +0000844 (u_char *) buffer_ptr(&incoming_packet),
Ben Lindstrom06b33aa2001-02-15 03:01:59 +0000845 buffer_len(&incoming_packet));
Damien Miller33b13562000-04-04 14:38:59 +1000846 if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0)
Damien Miller874d77b2000-10-14 16:23:11 +1100847 packet_disconnect("Corrupted MAC on input.");
848 DBG(debug("MAC #%d ok", seqnr));
Damien Miller33b13562000-04-04 14:38:59 +1000849 buffer_consume(&input, mac->mac_len);
850 }
Damien Miller4af51302000-04-16 11:18:38 +1000851 if (++seqnr == 0)
852 log("incoming seqnr wraps around");
Damien Miller33b13562000-04-04 14:38:59 +1000853
854 /* get padlen */
855 cp = buffer_ptr(&incoming_packet) + 4;
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000856 padlen = (u_char) *cp;
Damien Miller33b13562000-04-04 14:38:59 +1000857 DBG(debug("input: padlen %d", padlen));
858 if (padlen < 4)
859 packet_disconnect("Corrupted padlen %d on input.", padlen);
860
861 /* skip packet size + padlen, discard padding */
862 buffer_consume(&incoming_packet, 4 + 1);
863 buffer_consume_end(&incoming_packet, padlen);
864
865 DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet)));
866 if (comp && comp->enabled) {
867 buffer_clear(&compression_buffer);
868 buffer_uncompress(&incoming_packet, &compression_buffer);
869 buffer_clear(&incoming_packet);
870 buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
871 buffer_len(&compression_buffer));
872 DBG(debug("input: len after de-compress %d", buffer_len(&incoming_packet)));
873 }
874 /*
875 * get packet type, implies consume.
876 * return length of payload (without type field)
877 */
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000878 type = buffer_get_char(&incoming_packet);
Ben Lindstrom2d90e002001-04-04 02:00:54 +0000879 if (type == SSH2_MSG_NEWKEYS)
880 set_newkeys(MODE_IN);
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000881 *payload_len_ptr = buffer_len(&incoming_packet);
Damien Miller33b13562000-04-04 14:38:59 +1000882#ifdef PACKET_DEBUG
Ben Lindstrom204e4882001-03-05 06:47:00 +0000883 fprintf(stderr, "read/plain[%d]:\r\n", type);
Damien Miller33b13562000-04-04 14:38:59 +1000884 buffer_dump(&incoming_packet);
885#endif
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000886 /* reset for next packet */
887 packet_length = 0;
888 return type;
Damien Miller33b13562000-04-04 14:38:59 +1000889}
890
891int
892packet_read_poll(int *payload_len_ptr)
893{
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000894 int reason;
895 u_char type;
Damien Miller33b13562000-04-04 14:38:59 +1000896 char *msg;
Damien Miller33b13562000-04-04 14:38:59 +1000897
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000898 for (;;) {
899 if (compat20) {
900 type = packet_read_poll2(payload_len_ptr);
901 if (type)
Damien Miller33b13562000-04-04 14:38:59 +1000902 DBG(debug("received packet type %d", type));
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +0000903 switch (type) {
Damien Miller33b13562000-04-04 14:38:59 +1000904 case SSH2_MSG_IGNORE:
905 break;
906 case SSH2_MSG_DEBUG:
907 packet_get_char();
908 msg = packet_get_string(NULL);
909 debug("Remote: %.900s", msg);
910 xfree(msg);
911 msg = packet_get_string(NULL);
912 xfree(msg);
913 break;
914 case SSH2_MSG_DISCONNECT:
915 reason = packet_get_int();
916 msg = packet_get_string(NULL);
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000917 log("Received disconnect from %s: %d: %.400s", get_remote_ipaddr(),
918 reason, msg);
Damien Miller33b13562000-04-04 14:38:59 +1000919 xfree(msg);
920 fatal_cleanup();
921 break;
922 default:
923 return type;
924 break;
Kevin Stevesef4eea92001-02-05 12:42:17 +0000925 }
Damien Miller33b13562000-04-04 14:38:59 +1000926 } else {
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000927 type = packet_read_poll1(payload_len_ptr);
Ben Lindstrom1c37c6a2001-12-06 18:00:18 +0000928 switch (type) {
Damien Miller33b13562000-04-04 14:38:59 +1000929 case SSH_MSG_IGNORE:
930 break;
931 case SSH_MSG_DEBUG:
932 msg = packet_get_string(NULL);
933 debug("Remote: %.900s", msg);
934 xfree(msg);
935 break;
936 case SSH_MSG_DISCONNECT:
937 msg = packet_get_string(NULL);
Ben Lindstrom5c1fbab2001-01-03 03:51:15 +0000938 log("Received disconnect from %s: %.400s", get_remote_ipaddr(),
939 msg);
Damien Miller33b13562000-04-04 14:38:59 +1000940 fatal_cleanup();
941 xfree(msg);
942 break;
943 default:
Ben Lindstrom80c6d772001-06-05 21:09:18 +0000944 if (type)
Damien Miller33b13562000-04-04 14:38:59 +1000945 DBG(debug("received packet type %d", type));
946 return type;
947 break;
Kevin Stevesef4eea92001-02-05 12:42:17 +0000948 }
Damien Miller33b13562000-04-04 14:38:59 +1000949 }
950 }
951}
952
Damien Miller5428f641999-11-25 11:54:57 +1100953/*
954 * Buffers the given amount of input characters. This is intended to be used
955 * together with packet_read_poll.
956 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000957
958void
Ben Lindstrom46c16222000-12-22 01:43:59 +0000959packet_process_incoming(const char *buf, u_int len)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000960{
Damien Miller95def091999-11-25 00:26:21 +1100961 buffer_append(&input, buf, len);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000962}
963
964/* Returns a character from the packet. */
965
Ben Lindstrom46c16222000-12-22 01:43:59 +0000966u_int
Ben Lindstrom3c36bb22001-12-06 17:55:26 +0000967packet_get_char(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000968{
Damien Miller95def091999-11-25 00:26:21 +1100969 char ch;
970 buffer_get(&incoming_packet, &ch, 1);
Ben Lindstrom46c16222000-12-22 01:43:59 +0000971 return (u_char) ch;
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000972}
973
974/* Returns an integer from the packet data. */
975
Ben Lindstrom46c16222000-12-22 01:43:59 +0000976u_int
Ben Lindstrom3c36bb22001-12-06 17:55:26 +0000977packet_get_int(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000978{
Damien Miller95def091999-11-25 00:26:21 +1100979 return buffer_get_int(&incoming_packet);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000980}
981
Damien Miller5428f641999-11-25 11:54:57 +1100982/*
983 * Returns an arbitrary precision integer from the packet data. The integer
984 * must have been initialized before this call.
985 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000986
987void
Damien Miller95def091999-11-25 00:26:21 +1100988packet_get_bignum(BIGNUM * value, int *length_ptr)
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000989{
Damien Miller95def091999-11-25 00:26:21 +1100990 *length_ptr = buffer_get_bignum(&incoming_packet, value);
Damien Millerd4a8b7e1999-10-27 13:42:43 +1000991}
992
Damien Miller33b13562000-04-04 14:38:59 +1000993void
994packet_get_bignum2(BIGNUM * value, int *length_ptr)
995{
996 *length_ptr = buffer_get_bignum2(&incoming_packet, value);
997}
998
999char *
1000packet_get_raw(int *length_ptr)
1001{
1002 int bytes = buffer_len(&incoming_packet);
1003 if (length_ptr != NULL)
1004 *length_ptr = bytes;
1005 return buffer_ptr(&incoming_packet);
1006}
1007
Damien Miller4af51302000-04-16 11:18:38 +10001008int
1009packet_remaining(void)
1010{
1011 return buffer_len(&incoming_packet);
1012}
1013
Damien Miller5428f641999-11-25 11:54:57 +11001014/*
1015 * Returns a string from the packet data. The string is allocated using
1016 * xmalloc; it is the responsibility of the calling program to free it when
1017 * no longer needed. The length_ptr argument may be NULL, or point to an
1018 * integer into which the length of the string is stored.
1019 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001020
Damien Miller5428f641999-11-25 11:54:57 +11001021char *
Ben Lindstrom46c16222000-12-22 01:43:59 +00001022packet_get_string(u_int *length_ptr)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001023{
Damien Miller95def091999-11-25 00:26:21 +11001024 return buffer_get_string(&incoming_packet, length_ptr);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001025}
1026
Damien Miller5428f641999-11-25 11:54:57 +11001027/*
1028 * Sends a diagnostic message from the server to the client. This message
1029 * can be sent at any time (but not while constructing another message). The
1030 * message is printed immediately, but only if the client is being executed
1031 * in verbose mode. These messages are primarily intended to ease debugging
1032 * authentication problems. The length of the formatted message must not
1033 * exceed 1024 bytes. This will automatically call packet_write_wait.
1034 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001035
1036void
Damien Miller95def091999-11-25 00:26:21 +11001037packet_send_debug(const char *fmt,...)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001038{
Damien Miller95def091999-11-25 00:26:21 +11001039 char buf[1024];
1040 va_list args;
1041
Ben Lindstroma14ee472000-12-07 01:24:58 +00001042 if (compat20 && (datafellows & SSH_BUG_DEBUG))
1043 return;
1044
Damien Miller95def091999-11-25 00:26:21 +11001045 va_start(args, fmt);
1046 vsnprintf(buf, sizeof(buf), fmt, args);
1047 va_end(args);
1048
Damien Miller7c8af4f2000-05-01 08:24:07 +10001049 if (compat20) {
1050 packet_start(SSH2_MSG_DEBUG);
1051 packet_put_char(0); /* bool: always display */
1052 packet_put_cstring(buf);
1053 packet_put_cstring("");
1054 } else {
1055 packet_start(SSH_MSG_DEBUG);
1056 packet_put_cstring(buf);
1057 }
Damien Miller95def091999-11-25 00:26:21 +11001058 packet_send();
1059 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001060}
1061
Damien Miller5428f641999-11-25 11:54:57 +11001062/*
1063 * Logs the error plus constructs and sends a disconnect packet, closes the
1064 * connection, and exits. This function never returns. The error message
1065 * should not contain a newline. The length of the formatted message must
1066 * not exceed 1024 bytes.
1067 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001068
1069void
Damien Miller95def091999-11-25 00:26:21 +11001070packet_disconnect(const char *fmt,...)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001071{
Damien Miller95def091999-11-25 00:26:21 +11001072 char buf[1024];
1073 va_list args;
1074 static int disconnecting = 0;
1075 if (disconnecting) /* Guard against recursive invocations. */
1076 fatal("packet_disconnect called recursively.");
1077 disconnecting = 1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001078
Damien Miller5428f641999-11-25 11:54:57 +11001079 /*
1080 * Format the message. Note that the caller must make sure the
1081 * message is of limited size.
1082 */
Damien Miller95def091999-11-25 00:26:21 +11001083 va_start(args, fmt);
1084 vsnprintf(buf, sizeof(buf), fmt, args);
1085 va_end(args);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001086
Damien Miller95def091999-11-25 00:26:21 +11001087 /* Send the disconnect message to the other side, and wait for it to get sent. */
Damien Miller33b13562000-04-04 14:38:59 +10001088 if (compat20) {
1089 packet_start(SSH2_MSG_DISCONNECT);
1090 packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR);
1091 packet_put_cstring(buf);
1092 packet_put_cstring("");
1093 } else {
1094 packet_start(SSH_MSG_DISCONNECT);
Ben Lindstrom664408d2001-06-09 01:42:01 +00001095 packet_put_cstring(buf);
Damien Miller33b13562000-04-04 14:38:59 +10001096 }
Damien Miller95def091999-11-25 00:26:21 +11001097 packet_send();
1098 packet_write_wait();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001099
Damien Miller95def091999-11-25 00:26:21 +11001100 /* Stop listening for connections. */
Ben Lindstrom601e4362001-06-21 03:19:23 +00001101 channel_close_all();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001102
Damien Miller95def091999-11-25 00:26:21 +11001103 /* Close the connection. */
1104 packet_close();
1105
1106 /* Display the error locally and exit. */
Damien Milleraae6c611999-12-06 11:47:28 +11001107 log("Disconnecting: %.100s", buf);
1108 fatal_cleanup();
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001109}
1110
Damien Miller5428f641999-11-25 11:54:57 +11001111/* Checks if there is any buffered output, and tries to write some of the output. */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001112
1113void
Ben Lindstrom3c36bb22001-12-06 17:55:26 +00001114packet_write_poll(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001115{
Damien Miller95def091999-11-25 00:26:21 +11001116 int len = buffer_len(&output);
1117 if (len > 0) {
1118 len = write(connection_out, buffer_ptr(&output), len);
1119 if (len <= 0) {
1120 if (errno == EAGAIN)
1121 return;
1122 else
1123 fatal("Write failed: %.100s", strerror(errno));
1124 }
1125 buffer_consume(&output, len);
1126 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001127}
1128
Damien Miller5428f641999-11-25 11:54:57 +11001129/*
1130 * Calls packet_write_poll repeatedly until all pending output data has been
1131 * written.
1132 */
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001133
1134void
Ben Lindstrom3c36bb22001-12-06 17:55:26 +00001135packet_write_wait(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001136{
Ben Lindstromcb978aa2001-03-05 07:07:49 +00001137 fd_set *setp;
1138
1139 setp = (fd_set *)xmalloc(howmany(connection_out + 1, NFDBITS) *
1140 sizeof(fd_mask));
Damien Miller95def091999-11-25 00:26:21 +11001141 packet_write_poll();
1142 while (packet_have_data_to_write()) {
Ben Lindstromcb978aa2001-03-05 07:07:49 +00001143 memset(setp, 0, howmany(connection_out + 1, NFDBITS) *
1144 sizeof(fd_mask));
1145 FD_SET(connection_out, setp);
1146 while (select(connection_out + 1, NULL, setp, NULL, NULL) == -1 &&
Ben Lindstromf9452512001-02-15 03:12:08 +00001147 (errno == EAGAIN || errno == EINTR))
1148 ;
Damien Miller95def091999-11-25 00:26:21 +11001149 packet_write_poll();
1150 }
Ben Lindstromcb978aa2001-03-05 07:07:49 +00001151 xfree(setp);
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001152}
1153
1154/* Returns true if there is buffered data to write to the connection. */
1155
1156int
Ben Lindstrom3c36bb22001-12-06 17:55:26 +00001157packet_have_data_to_write(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001158{
Damien Miller95def091999-11-25 00:26:21 +11001159 return buffer_len(&output) != 0;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001160}
1161
1162/* Returns true if there is not too much data to write to the connection. */
1163
1164int
Ben Lindstrom3c36bb22001-12-06 17:55:26 +00001165packet_not_very_much_data_to_write(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001166{
Damien Miller95def091999-11-25 00:26:21 +11001167 if (interactive_mode)
1168 return buffer_len(&output) < 16384;
1169 else
1170 return buffer_len(&output) < 128 * 1024;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001171}
1172
1173/* Informs that the current session is interactive. Sets IP flags for that. */
1174
1175void
Ben Lindstrombf555ba2001-01-18 02:04:35 +00001176packet_set_interactive(int interactive)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001177{
Ben Lindstrombf555ba2001-01-18 02:04:35 +00001178 static int called = 0;
Damien Miller0bcf9ea2001-02-27 14:03:30 +11001179#if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN)
Ben Lindstrombf555ba2001-01-18 02:04:35 +00001180 int lowdelay = IPTOS_LOWDELAY;
1181 int throughput = IPTOS_THROUGHPUT;
Damien Miller0bcf9ea2001-02-27 14:03:30 +11001182#endif
Damien Miller95def091999-11-25 00:26:21 +11001183 int on = 1;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001184
Ben Lindstrombf555ba2001-01-18 02:04:35 +00001185 if (called)
1186 return;
1187 called = 1;
1188
Damien Miller95def091999-11-25 00:26:21 +11001189 /* Record that we are in interactive mode. */
1190 interactive_mode = interactive;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001191
Damien Miller34132e52000-01-14 15:45:46 +11001192 /* Only set socket options if using a socket. */
1193 if (!packet_connection_is_on_socket())
Damien Miller95def091999-11-25 00:26:21 +11001194 return;
Damien Miller34132e52000-01-14 15:45:46 +11001195 /*
Ben Lindstrom2f959b42001-01-11 06:20:23 +00001196 * IPTOS_LOWDELAY and IPTOS_THROUGHPUT are IPv4 only
Damien Miller34132e52000-01-14 15:45:46 +11001197 */
Damien Miller95def091999-11-25 00:26:21 +11001198 if (interactive) {
Damien Miller5428f641999-11-25 11:54:57 +11001199 /*
1200 * Set IP options for an interactive connection. Use
1201 * IPTOS_LOWDELAY and TCP_NODELAY.
1202 */
Damien Miller2ae714f2000-07-11 09:29:50 +10001203#if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN)
Ben Lindstrom2f959b42001-01-11 06:20:23 +00001204 if (packet_connection_is_ipv4()) {
Kevin Steves0c696152001-01-24 13:47:43 +00001205 if (setsockopt(connection_in, IPPROTO_IP, IP_TOS,
Ben Lindstrom2f959b42001-01-11 06:20:23 +00001206 (void *) &lowdelay, sizeof(lowdelay)) < 0)
Kevin Steves0c696152001-01-24 13:47:43 +00001207 error("setsockopt IPTOS_LOWDELAY: %.100s",
Ben Lindstrom2f959b42001-01-11 06:20:23 +00001208 strerror(errno));
1209 }
Damien Miller615f9392000-05-17 22:53:33 +10001210#endif
Damien Miller95def091999-11-25 00:26:21 +11001211 if (setsockopt(connection_in, IPPROTO_TCP, TCP_NODELAY, (void *) &on,
Damien Miller34132e52000-01-14 15:45:46 +11001212 sizeof(on)) < 0)
Damien Miller95def091999-11-25 00:26:21 +11001213 error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
Ben Lindstrom2f959b42001-01-11 06:20:23 +00001214 } else if (packet_connection_is_ipv4()) {
Damien Miller5428f641999-11-25 11:54:57 +11001215 /*
1216 * Set IP options for a non-interactive connection. Use
1217 * IPTOS_THROUGHPUT.
1218 */
Damien Miller2ae714f2000-07-11 09:29:50 +10001219#if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN)
Damien Miller95def091999-11-25 00:26:21 +11001220 if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &throughput,
Damien Miller34132e52000-01-14 15:45:46 +11001221 sizeof(throughput)) < 0)
Damien Miller95def091999-11-25 00:26:21 +11001222 error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno));
Damien Miller615f9392000-05-17 22:53:33 +10001223#endif
Damien Miller95def091999-11-25 00:26:21 +11001224 }
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001225}
1226
1227/* Returns true if the current connection is interactive. */
1228
1229int
Ben Lindstrom3c36bb22001-12-06 17:55:26 +00001230packet_is_interactive(void)
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001231{
Damien Miller95def091999-11-25 00:26:21 +11001232 return interactive_mode;
Damien Millerd4a8b7e1999-10-27 13:42:43 +10001233}
Damien Miller6162d121999-11-21 13:23:52 +11001234
1235int
1236packet_set_maxsize(int s)
1237{
Damien Miller95def091999-11-25 00:26:21 +11001238 static int called = 0;
1239 if (called) {
Damien Miller33b13562000-04-04 14:38:59 +10001240 log("packet_set_maxsize: called twice: old %d new %d",
1241 max_packet_size, s);
Damien Miller95def091999-11-25 00:26:21 +11001242 return -1;
1243 }
1244 if (s < 4 * 1024 || s > 1024 * 1024) {
1245 log("packet_set_maxsize: bad size %d", s);
1246 return -1;
1247 }
Ben Lindstromae3de4b2001-10-03 17:10:17 +00001248 called = 1;
Ben Lindstrom16d45b32001-06-13 04:39:18 +00001249 debug("packet_set_maxsize: setting to %d", s);
Damien Miller95def091999-11-25 00:26:21 +11001250 max_packet_size = s;
1251 return s;
Damien Miller6162d121999-11-21 13:23:52 +11001252}
Ben Lindstrom5699c5f2001-03-05 06:17:49 +00001253
Damien Miller9f643902001-11-12 11:02:52 +11001254/* roundup current message to pad bytes */
1255void
1256packet_add_padding(u_char pad)
1257{
1258 extra_pad = pad;
1259}
1260
Ben Lindstrom5699c5f2001-03-05 06:17:49 +00001261/*
1262 * 9.2. Ignored Data Message
Ben Lindstroma3700052001-04-05 23:26:32 +00001263 *
Ben Lindstrom5699c5f2001-03-05 06:17:49 +00001264 * byte SSH_MSG_IGNORE
1265 * string data
Ben Lindstroma3700052001-04-05 23:26:32 +00001266 *
Ben Lindstrom5699c5f2001-03-05 06:17:49 +00001267 * All implementations MUST understand (and ignore) this message at any
1268 * time (after receiving the protocol version). No implementation is
1269 * required to send them. This message can be used as an additional
1270 * protection measure against advanced traffic analysis techniques.
1271 */
Ben Lindstrome229b252001-03-05 06:28:06 +00001272void
1273packet_send_ignore(int nbytes)
1274{
1275 u_int32_t rand = 0;
1276 int i;
1277
1278 packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE);
Ben Lindstrom5699c5f2001-03-05 06:17:49 +00001279 packet_put_int(nbytes);
1280 for(i = 0; i < nbytes; i++) {
1281 if (i % 4 == 0)
1282 rand = arc4random();
1283 packet_put_char(rand & 0xff);
1284 rand >>= 8;
1285 }
1286}