Annotation of src/usr.bin/ssh/packet.c, Revision 1.35
1.1 deraadt 1: /*
1.15 deraadt 2: * Author: Tatu Ylonen <ylo@cs.hut.fi>
3: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4: * All rights reserved
1.35 ! deraadt 5: * 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.
1.29 markus 7: *
1.35 ! deraadt 8: * 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".
1.29 markus 13: *
1.25 markus 14: *
15: * SSH2 packet format added by Markus Friedl.
1.35 ! deraadt 16: * Copyright (c) 2000 Markus Friedl. All rights reserved.
1.25 markus 17: *
1.35 ! deraadt 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.
1.15 deraadt 37: */
1.1 deraadt 38:
39: #include "includes.h"
1.35 ! deraadt 40: RCSID("$OpenBSD: packet.c,v 1.34 2000/08/19 02:17:12 deraadt Exp $");
1.1 deraadt 41:
42: #include "xmalloc.h"
43: #include "buffer.h"
44: #include "packet.h"
45: #include "bufaux.h"
46: #include "ssh.h"
47: #include "crc32.h"
48: #include "cipher.h"
49: #include "getput.h"
50:
51: #include "compress.h"
1.9 dugsong 52: #include "deattack.h"
1.23 markus 53: #include "channels.h"
1.1 deraadt 54:
1.25 markus 55: #include "compat.h"
56: #include "ssh2.h"
57:
1.27 markus 58: #include <openssl/bn.h>
59: #include <openssl/dh.h>
60: #include <openssl/hmac.h>
1.25 markus 61: #include "buffer.h"
62: #include "kex.h"
63: #include "hmac.h"
64:
65: #ifdef PACKET_DEBUG
66: #define DBG(x) x
67: #else
68: #define DBG(x)
69: #endif
70:
1.16 markus 71: /*
72: * This variable contains the file descriptors used for communicating with
73: * the other side. connection_in is used for reading; connection_out for
74: * writing. These can be the same descriptor, in which case it is assumed to
75: * be a socket.
76: */
1.1 deraadt 77: static int connection_in = -1;
78: static int connection_out = -1;
79:
1.16 markus 80: /*
81: * Cipher type. This value is only used to determine whether to pad the
82: * packets with zeroes or random data.
83: */
1.1 deraadt 84: static int cipher_type = SSH_CIPHER_NONE;
85:
86: /* Protocol flags for the remote side. */
87: static unsigned int remote_protocol_flags = 0;
88:
89: /* Encryption context for receiving data. This is only used for decryption. */
90: static CipherContext receive_context;
1.14 markus 91:
92: /* Encryption context for sending data. This is only used for encryption. */
1.1 deraadt 93: static CipherContext send_context;
94:
95: /* Buffer for raw input data from the socket. */
96: static Buffer input;
97:
98: /* Buffer for raw output data going to the socket. */
99: static Buffer output;
100:
101: /* Buffer for the partial outgoing packet being constructed. */
102: static Buffer outgoing_packet;
103:
104: /* Buffer for the incoming packet currently being processed. */
105: static Buffer incoming_packet;
106:
107: /* Scratch buffer for packet compression/decompression. */
108: static Buffer compression_buffer;
109:
110: /* Flag indicating whether packet compression/decompression is enabled. */
111: static int packet_compression = 0;
112:
1.12 markus 113: /* default maximum packet size */
114: int max_packet_size = 32768;
115:
1.1 deraadt 116: /* Flag indicating whether this module has been initialized. */
117: static int initialized = 0;
118:
119: /* Set to true if the connection is interactive. */
120: static int interactive_mode = 0;
121:
1.25 markus 122: /* True if SSH2 packet format is used */
123: int use_ssh2_packet_format = 0;
124:
125: /* Session key information for Encryption and MAC */
126: Kex *kex = NULL;
127:
128: void
129: packet_set_kex(Kex *k)
130: {
131: if( k->mac[MODE_IN ].key == NULL ||
132: k->enc[MODE_IN ].key == NULL ||
133: k->enc[MODE_IN ].iv == NULL ||
134: k->mac[MODE_OUT].key == NULL ||
135: k->enc[MODE_OUT].key == NULL ||
136: k->enc[MODE_OUT].iv == NULL)
137: fatal("bad KEX");
138: kex = k;
139: }
140: void
141: clear_enc_keys(Enc *enc, int len)
142: {
143: memset(enc->iv, 0, len);
144: memset(enc->key, 0, len);
145: xfree(enc->iv);
146: xfree(enc->key);
147: enc->iv = NULL;
148: enc->key = NULL;
149: }
150: void
151: packet_set_ssh2_format(void)
152: {
1.31 markus 153: DBG(debug("use_ssh2_packet_format"));
1.25 markus 154: use_ssh2_packet_format = 1;
155: }
156:
1.16 markus 157: /*
158: * Sets the descriptors used for communication. Disables encryption until
159: * packet_set_encryption_key is called.
160: */
1.2 provos 161: void
162: packet_set_connection(int fd_in, int fd_out)
1.1 deraadt 163: {
1.14 markus 164: connection_in = fd_in;
165: connection_out = fd_out;
166: cipher_type = SSH_CIPHER_NONE;
1.26 markus 167: cipher_set_key(&send_context, SSH_CIPHER_NONE, (unsigned char *) "", 0);
168: cipher_set_key(&receive_context, SSH_CIPHER_NONE, (unsigned char *) "", 0);
1.14 markus 169: if (!initialized) {
170: initialized = 1;
171: buffer_init(&input);
172: buffer_init(&output);
173: buffer_init(&outgoing_packet);
174: buffer_init(&incoming_packet);
175: }
176: /* Kludge: arrange the close function to be called from fatal(). */
177: fatal_add_cleanup((void (*) (void *)) packet_close, NULL);
1.1 deraadt 178: }
179:
1.19 markus 180: /* Returns 1 if remote host is connected via socket, 0 if not. */
181:
182: int
183: packet_connection_is_on_socket()
184: {
185: struct sockaddr_storage from, to;
186: socklen_t fromlen, tolen;
187:
188: /* filedescriptors in and out are the same, so it's a socket */
189: if (connection_in == connection_out)
190: return 1;
191: fromlen = sizeof(from);
192: memset(&from, 0, sizeof(from));
1.20 markus 193: if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0)
1.19 markus 194: return 0;
195: tolen = sizeof(to);
196: memset(&to, 0, sizeof(to));
1.20 markus 197: if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0)
1.19 markus 198: return 0;
199: if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
200: return 0;
201: if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
202: return 0;
203: return 1;
204: }
205:
206: /* returns 1 if connection is via ipv4 */
207:
208: int
209: packet_connection_is_ipv4()
210: {
211: struct sockaddr_storage to;
1.21 deraadt 212: socklen_t tolen = sizeof(to);
1.19 markus 213:
214: memset(&to, 0, sizeof(to));
215: if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0)
216: return 0;
217: if (to.ss_family != AF_INET)
218: return 0;
219: return 1;
220: }
221:
1.1 deraadt 222: /* Sets the connection into non-blocking mode. */
223:
1.2 provos 224: void
225: packet_set_nonblocking()
1.1 deraadt 226: {
1.14 markus 227: /* Set the socket into non-blocking mode. */
228: if (fcntl(connection_in, F_SETFL, O_NONBLOCK) < 0)
229: error("fcntl O_NONBLOCK: %.100s", strerror(errno));
230:
231: if (connection_out != connection_in) {
232: if (fcntl(connection_out, F_SETFL, O_NONBLOCK) < 0)
233: error("fcntl O_NONBLOCK: %.100s", strerror(errno));
234: }
1.1 deraadt 235: }
236:
237: /* Returns the socket used for reading. */
238:
1.2 provos 239: int
240: packet_get_connection_in()
1.1 deraadt 241: {
1.14 markus 242: return connection_in;
1.1 deraadt 243: }
244:
245: /* Returns the descriptor used for writing. */
246:
1.2 provos 247: int
248: packet_get_connection_out()
1.1 deraadt 249: {
1.14 markus 250: return connection_out;
1.1 deraadt 251: }
252:
253: /* Closes the connection and clears and frees internal data structures. */
254:
1.2 provos 255: void
256: packet_close()
1.1 deraadt 257: {
1.14 markus 258: if (!initialized)
259: return;
260: initialized = 0;
261: if (connection_in == connection_out) {
262: shutdown(connection_out, SHUT_RDWR);
263: close(connection_out);
264: } else {
265: close(connection_in);
266: close(connection_out);
267: }
268: buffer_free(&input);
269: buffer_free(&output);
270: buffer_free(&outgoing_packet);
271: buffer_free(&incoming_packet);
272: if (packet_compression) {
273: buffer_free(&compression_buffer);
274: buffer_compress_uninit();
275: }
1.1 deraadt 276: }
277:
278: /* Sets remote side protocol flags. */
279:
1.2 provos 280: void
281: packet_set_protocol_flags(unsigned int protocol_flags)
1.1 deraadt 282: {
1.14 markus 283: remote_protocol_flags = protocol_flags;
284: channel_set_options((protocol_flags & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) != 0);
1.1 deraadt 285: }
286:
287: /* Returns the remote protocol flags set earlier by the above function. */
288:
1.2 provos 289: unsigned int
290: packet_get_protocol_flags()
1.1 deraadt 291: {
1.14 markus 292: return remote_protocol_flags;
1.1 deraadt 293: }
294:
1.16 markus 295: /*
296: * Starts packet compression from the next packet on in both directions.
297: * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
298: */
1.1 deraadt 299:
1.25 markus 300: /*** XXXXX todo: kex means re-init */
1.2 provos 301: void
302: packet_start_compression(int level)
1.1 deraadt 303: {
1.14 markus 304: if (packet_compression)
305: fatal("Compression already enabled.");
306: packet_compression = 1;
307: buffer_init(&compression_buffer);
308: buffer_compress_init(level);
1.1 deraadt 309: }
310:
1.16 markus 311: /*
312: * Encrypts the given number of bytes, copying from src to dest. bytes is
313: * known to be a multiple of 8.
314: */
1.1 deraadt 315:
1.2 provos 316: void
1.14 markus 317: packet_encrypt(CipherContext * cc, void *dest, void *src,
1.25 markus 318: unsigned int bytes)
1.1 deraadt 319: {
1.14 markus 320: cipher_encrypt(cc, dest, src, bytes);
1.1 deraadt 321: }
322:
1.16 markus 323: /*
324: * Decrypts the given number of bytes, copying from src to dest. bytes is
325: * known to be a multiple of 8.
326: */
1.1 deraadt 327:
1.2 provos 328: void
1.14 markus 329: packet_decrypt(CipherContext * cc, void *dest, void *src,
1.25 markus 330: unsigned int bytes)
1.1 deraadt 331: {
1.14 markus 332: int i;
333:
334: if ((bytes % 8) != 0)
335: fatal("packet_decrypt: bad ciphertext length %d", bytes);
336:
1.16 markus 337: /*
338: * Cryptographic attack detector for ssh - Modifications for packet.c
339: * (C)1998 CORE-SDI, Buenos Aires Argentina Ariel Futoransky(futo@core-sdi.com)
340: */
1.14 markus 341:
1.25 markus 342: if (cc->type == SSH_CIPHER_NONE || compat20) {
1.14 markus 343: i = DEATTACK_OK;
1.25 markus 344: } else {
1.14 markus 345: i = detect_attack(src, bytes, NULL);
346: }
347: if (i == DEATTACK_DETECTED)
348: packet_disconnect("crc32 compensation attack: network attack detected");
349:
350: cipher_decrypt(cc, dest, src, bytes);
1.1 deraadt 351: }
352:
1.16 markus 353: /*
354: * Causes any further packets to be encrypted using the given key. The same
355: * key is used for both sending and reception. However, both directions are
356: * encrypted independently of each other.
357: */
1.1 deraadt 358:
1.2 provos 359: void
360: packet_set_encryption_key(const unsigned char *key, unsigned int keylen,
1.25 markus 361: int cipher)
1.1 deraadt 362: {
1.25 markus 363: if (keylen < 20)
364: fatal("keylen too small: %d", keylen);
365:
1.14 markus 366: /* All other ciphers use the same key in both directions for now. */
1.26 markus 367: cipher_set_key(&receive_context, cipher, key, keylen);
368: cipher_set_key(&send_context, cipher, key, keylen);
1.1 deraadt 369: }
370:
371: /* Starts constructing a packet to send. */
372:
1.2 provos 373: void
1.25 markus 374: packet_start1(int type)
1.1 deraadt 375: {
1.14 markus 376: char buf[9];
1.1 deraadt 377:
1.14 markus 378: buffer_clear(&outgoing_packet);
379: memset(buf, 0, 8);
380: buf[8] = type;
381: buffer_append(&outgoing_packet, buf, 9);
1.1 deraadt 382: }
383:
1.25 markus 384: void
385: packet_start2(int type)
386: {
387: char buf[4+1+1];
388:
389: buffer_clear(&outgoing_packet);
390: memset(buf, 0, sizeof buf);
391: /* buf[0..3] = payload_len; */
392: /* buf[4] = pad_len; */
393: buf[5] = type & 0xff;
394: buffer_append(&outgoing_packet, buf, sizeof buf);
395: }
396:
397: void
398: packet_start(int type)
399: {
400: DBG(debug("packet_start[%d]",type));
401: if (use_ssh2_packet_format)
402: packet_start2(type);
403: else
404: packet_start1(type);
405: }
406:
1.1 deraadt 407: /* Appends a character to the packet data. */
408:
1.2 provos 409: void
410: packet_put_char(int value)
1.1 deraadt 411: {
1.14 markus 412: char ch = value;
413: buffer_append(&outgoing_packet, &ch, 1);
1.1 deraadt 414: }
415:
416: /* Appends an integer to the packet data. */
417:
1.2 provos 418: void
419: packet_put_int(unsigned int value)
1.1 deraadt 420: {
1.14 markus 421: buffer_put_int(&outgoing_packet, value);
1.1 deraadt 422: }
423:
424: /* Appends a string to packet data. */
425:
1.2 provos 426: void
427: packet_put_string(const char *buf, unsigned int len)
1.1 deraadt 428: {
1.14 markus 429: buffer_put_string(&outgoing_packet, buf, len);
1.1 deraadt 430: }
1.24 markus 431: void
432: packet_put_cstring(const char *str)
433: {
434: buffer_put_string(&outgoing_packet, str, strlen(str));
435: }
436:
437: void
438: packet_put_raw(const char *buf, unsigned int len)
439: {
440: buffer_append(&outgoing_packet, buf, len);
441: }
442:
1.1 deraadt 443:
444: /* Appends an arbitrary precision integer to packet data. */
445:
1.2 provos 446: void
1.14 markus 447: packet_put_bignum(BIGNUM * value)
1.1 deraadt 448: {
1.14 markus 449: buffer_put_bignum(&outgoing_packet, value);
1.1 deraadt 450: }
1.24 markus 451: void
452: packet_put_bignum2(BIGNUM * value)
453: {
454: buffer_put_bignum2(&outgoing_packet, value);
455: }
1.1 deraadt 456:
1.16 markus 457: /*
458: * Finalizes and sends the packet. If the encryption key has been set,
459: * encrypts the packet before sending.
460: */
1.14 markus 461:
1.2 provos 462: void
1.25 markus 463: packet_send1()
1.1 deraadt 464: {
1.14 markus 465: char buf[8], *cp;
466: int i, padding, len;
467: unsigned int checksum;
468: u_int32_t rand = 0;
469:
1.16 markus 470: /*
471: * If using packet compression, compress the payload of the outgoing
472: * packet.
473: */
1.14 markus 474: if (packet_compression) {
475: buffer_clear(&compression_buffer);
476: /* Skip padding. */
477: buffer_consume(&outgoing_packet, 8);
478: /* padding */
479: buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8);
480: buffer_compress(&outgoing_packet, &compression_buffer);
481: buffer_clear(&outgoing_packet);
482: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
483: buffer_len(&compression_buffer));
484: }
485: /* Compute packet length without padding (add checksum, remove padding). */
486: len = buffer_len(&outgoing_packet) + 4 - 8;
487:
1.32 markus 488: /* Insert padding. Initialized to zero in packet_start1() */
1.14 markus 489: padding = 8 - len % 8;
490: if (cipher_type != SSH_CIPHER_NONE) {
491: cp = buffer_ptr(&outgoing_packet);
492: for (i = 0; i < padding; i++) {
493: if (i % 4 == 0)
494: rand = arc4random();
495: cp[7 - i] = rand & 0xff;
496: rand >>= 8;
497: }
498: }
499: buffer_consume(&outgoing_packet, 8 - padding);
500:
501: /* Add check bytes. */
1.34 deraadt 502: checksum = ssh_crc32((unsigned char *) buffer_ptr(&outgoing_packet),
503: buffer_len(&outgoing_packet));
1.14 markus 504: PUT_32BIT(buf, checksum);
505: buffer_append(&outgoing_packet, buf, 4);
1.1 deraadt 506:
507: #ifdef PACKET_DEBUG
1.14 markus 508: fprintf(stderr, "packet_send plain: ");
509: buffer_dump(&outgoing_packet);
1.1 deraadt 510: #endif
511:
1.14 markus 512: /* Append to output. */
513: PUT_32BIT(buf, len);
514: buffer_append(&output, buf, 4);
515: buffer_append_space(&output, &cp, buffer_len(&outgoing_packet));
516: packet_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),
517: buffer_len(&outgoing_packet));
518:
1.1 deraadt 519: #ifdef PACKET_DEBUG
1.14 markus 520: fprintf(stderr, "encrypted: ");
521: buffer_dump(&output);
1.1 deraadt 522: #endif
523:
1.14 markus 524: buffer_clear(&outgoing_packet);
1.1 deraadt 525:
1.16 markus 526: /*
527: * Note that the packet is now only buffered in output. It won\'t be
528: * actually sent until packet_write_wait or packet_write_poll is
529: * called.
530: */
1.1 deraadt 531: }
532:
1.16 markus 533: /*
1.25 markus 534: * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
535: */
536: void
537: packet_send2()
538: {
539: unsigned char *macbuf = NULL;
540: char *cp;
541: unsigned int packet_length = 0;
542: unsigned int i, padlen, len;
543: u_int32_t rand = 0;
1.29 markus 544: static unsigned int seqnr = 0;
1.25 markus 545: int type;
546: Enc *enc = NULL;
547: Mac *mac = NULL;
548: Comp *comp = NULL;
549: int block_size;
550:
551: if (kex != NULL) {
552: enc = &kex->enc[MODE_OUT];
553: mac = &kex->mac[MODE_OUT];
554: comp = &kex->comp[MODE_OUT];
555: }
556: block_size = enc ? enc->block_size : 8;
557:
558: cp = buffer_ptr(&outgoing_packet);
559: type = cp[5] & 0xff;
560:
561: #ifdef PACKET_DEBUG
562: fprintf(stderr, "plain: ");
563: buffer_dump(&outgoing_packet);
564: #endif
565:
566: if (comp && comp->enabled) {
567: len = buffer_len(&outgoing_packet);
568: /* skip header, compress only payload */
569: buffer_consume(&outgoing_packet, 5);
570: buffer_clear(&compression_buffer);
571: buffer_compress(&outgoing_packet, &compression_buffer);
572: buffer_clear(&outgoing_packet);
573: buffer_append(&outgoing_packet, "\0\0\0\0\0", 5);
574: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
575: buffer_len(&compression_buffer));
576: DBG(debug("compression: raw %d compressed %d", len,
577: buffer_len(&outgoing_packet)));
578: }
579:
580: /* sizeof (packet_len + pad_len + payload) */
581: len = buffer_len(&outgoing_packet);
582:
583: /*
584: * calc size of padding, alloc space, get random data,
585: * minimum padding is 4 bytes
586: */
587: padlen = block_size - (len % block_size);
588: if (padlen < 4)
589: padlen += block_size;
590: buffer_append_space(&outgoing_packet, &cp, padlen);
591: if (enc && enc->type != SSH_CIPHER_NONE) {
1.32 markus 592: /* random padding */
1.25 markus 593: for (i = 0; i < padlen; i++) {
594: if (i % 4 == 0)
595: rand = arc4random();
596: cp[i] = rand & 0xff;
597: rand <<= 8;
598: }
1.32 markus 599: } else {
600: /* clear padding */
601: memset(cp, 0, padlen);
1.25 markus 602: }
603: /* packet_length includes payload, padding and padding length field */
604: packet_length = buffer_len(&outgoing_packet) - 4;
605: cp = buffer_ptr(&outgoing_packet);
606: PUT_32BIT(cp, packet_length);
607: cp[4] = padlen & 0xff;
608: DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen));
609:
610: /* compute MAC over seqnr and packet(length fields, payload, padding) */
611: if (mac && mac->enabled) {
612: macbuf = hmac( mac->md, seqnr,
613: (unsigned char *) buffer_ptr(&outgoing_packet),
614: buffer_len(&outgoing_packet),
615: mac->key, mac->key_len
616: );
617: DBG(debug("done calc HMAC out #%d", seqnr));
618: }
619: /* encrypt packet and append to output buffer. */
620: buffer_append_space(&output, &cp, buffer_len(&outgoing_packet));
621: packet_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),
622: buffer_len(&outgoing_packet));
623: /* append unencrypted MAC */
624: if (mac && mac->enabled)
625: buffer_append(&output, (char *)macbuf, mac->mac_len);
626: #ifdef PACKET_DEBUG
627: fprintf(stderr, "encrypted: ");
628: buffer_dump(&output);
629: #endif
1.29 markus 630: /* increment sequence number for outgoing packets */
631: if (++seqnr == 0)
632: log("outgoing seqnr wraps around");
1.25 markus 633: buffer_clear(&outgoing_packet);
634:
635: if (type == SSH2_MSG_NEWKEYS) {
636: if (kex==NULL || mac==NULL || enc==NULL || comp==NULL)
637: fatal("packet_send2: no KEX");
638: if (mac->md != NULL)
639: mac->enabled = 1;
1.31 markus 640: DBG(debug("cipher_set_key_iv send_context"));
1.25 markus 641: cipher_set_key_iv(&send_context, enc->type,
642: enc->key, enc->key_len,
643: enc->iv, enc->iv_len);
644: clear_enc_keys(enc, kex->we_need);
645: if (comp->type != 0 && comp->enabled == 0) {
646: comp->enabled = 1;
647: if (! packet_compression)
648: packet_start_compression(6);
649: }
650: }
651: }
652:
653: void
654: packet_send()
655: {
656: if (use_ssh2_packet_format)
657: packet_send2();
658: else
659: packet_send1();
660: DBG(debug("packet_send done"));
661: }
662:
663: /*
1.16 markus 664: * Waits until a packet has been received, and returns its type. Note that
665: * no other data is processed until this returns, so this function should not
666: * be used during the interactive session.
667: */
1.1 deraadt 668:
1.2 provos 669: int
670: packet_read(int *payload_len_ptr)
1.1 deraadt 671: {
1.14 markus 672: int type, len;
673: fd_set set;
674: char buf[8192];
1.25 markus 675: DBG(debug("packet_read()"));
1.14 markus 676:
677: /* Since we are blocking, ensure that all written packets have been sent. */
678: packet_write_wait();
679:
680: /* Stay in the loop until we have received a complete packet. */
681: for (;;) {
682: /* Try to read a packet from the buffer. */
683: type = packet_read_poll(payload_len_ptr);
1.32 markus 684: if (!use_ssh2_packet_format && (
685: type == SSH_SMSG_SUCCESS
1.14 markus 686: || type == SSH_SMSG_FAILURE
687: || type == SSH_CMSG_EOF
1.32 markus 688: || type == SSH_CMSG_EXIT_CONFIRMATION))
1.14 markus 689: packet_integrity_check(*payload_len_ptr, 0, type);
690: /* If we got a packet, return it. */
691: if (type != SSH_MSG_NONE)
692: return type;
1.16 markus 693: /*
694: * Otherwise, wait for some data to arrive, add it to the
695: * buffer, and try again.
696: */
1.14 markus 697: FD_ZERO(&set);
698: FD_SET(connection_in, &set);
1.16 markus 699:
1.14 markus 700: /* Wait for some data to arrive. */
701: select(connection_in + 1, &set, NULL, NULL, NULL);
1.16 markus 702:
1.14 markus 703: /* Read data from the socket. */
704: len = read(connection_in, buf, sizeof(buf));
1.18 markus 705: if (len == 0) {
706: log("Connection closed by %.200s", get_remote_ipaddr());
707: fatal_cleanup();
708: }
1.14 markus 709: if (len < 0)
710: fatal("Read from socket failed: %.100s", strerror(errno));
711: /* Append it to the buffer. */
712: packet_process_incoming(buf, len);
713: }
714: /* NOTREACHED */
1.1 deraadt 715: }
716:
1.16 markus 717: /*
718: * Waits until a packet has been received, verifies that its type matches
719: * that given, and gives a fatal error and exits if there is a mismatch.
720: */
1.1 deraadt 721:
1.2 provos 722: void
723: packet_read_expect(int *payload_len_ptr, int expected_type)
1.1 deraadt 724: {
1.14 markus 725: int type;
1.1 deraadt 726:
1.14 markus 727: type = packet_read(payload_len_ptr);
728: if (type != expected_type)
729: packet_disconnect("Protocol error: expected packet type %d, got %d",
1.25 markus 730: expected_type, type);
1.1 deraadt 731: }
732:
733: /* Checks if a full packet is available in the data received so far via
1.14 markus 734: * packet_process_incoming. If so, reads the packet; otherwise returns
735: * SSH_MSG_NONE. This does not wait for data from the connection.
736: *
737: * SSH_MSG_DISCONNECT is handled specially here. Also,
738: * SSH_MSG_IGNORE messages are skipped by this function and are never returned
739: * to higher levels.
740: *
741: * The returned payload_len does include space consumed by:
742: * Packet length
743: * Padding
744: * Packet type
745: * Check bytes
746: */
1.1 deraadt 747:
1.2 provos 748: int
1.25 markus 749: packet_read_poll1(int *payload_len_ptr)
1.1 deraadt 750: {
1.14 markus 751: unsigned int len, padded_len;
752: unsigned char *ucp;
1.25 markus 753: char buf[8], *cp;
1.14 markus 754: unsigned int checksum, stored_checksum;
755:
756: /* Check if input size is less than minimum packet size. */
757: if (buffer_len(&input) < 4 + 8)
758: return SSH_MSG_NONE;
759: /* Get length of incoming packet. */
760: ucp = (unsigned char *) buffer_ptr(&input);
761: len = GET_32BIT(ucp);
762: if (len < 1 + 2 + 2 || len > 256 * 1024)
763: packet_disconnect("Bad packet length %d.", len);
764: padded_len = (len + 8) & ~7;
765:
766: /* Check if the packet has been entirely received. */
767: if (buffer_len(&input) < 4 + padded_len)
768: return SSH_MSG_NONE;
769:
770: /* The entire packet is in buffer. */
771:
772: /* Consume packet length. */
773: buffer_consume(&input, 4);
774:
775: /* Copy data to incoming_packet. */
776: buffer_clear(&incoming_packet);
777: buffer_append_space(&incoming_packet, &cp, padded_len);
778: packet_decrypt(&receive_context, cp, buffer_ptr(&input), padded_len);
779: buffer_consume(&input, padded_len);
1.1 deraadt 780:
781: #ifdef PACKET_DEBUG
1.14 markus 782: fprintf(stderr, "read_poll plain: ");
783: buffer_dump(&incoming_packet);
1.1 deraadt 784: #endif
785:
1.14 markus 786: /* Compute packet checksum. */
1.34 deraadt 787: checksum = ssh_crc32((unsigned char *) buffer_ptr(&incoming_packet),
1.25 markus 788: buffer_len(&incoming_packet) - 4);
1.14 markus 789:
790: /* Skip padding. */
791: buffer_consume(&incoming_packet, 8 - len % 8);
792:
793: /* Test check bytes. */
794:
795: if (len != buffer_len(&incoming_packet))
796: packet_disconnect("packet_read_poll: len %d != buffer_len %d.",
1.25 markus 797: len, buffer_len(&incoming_packet));
1.14 markus 798:
799: ucp = (unsigned char *) buffer_ptr(&incoming_packet) + len - 4;
800: stored_checksum = GET_32BIT(ucp);
801: if (checksum != stored_checksum)
802: packet_disconnect("Corrupted check bytes on input.");
803: buffer_consume_end(&incoming_packet, 4);
804:
805: /* If using packet compression, decompress the packet. */
806: if (packet_compression) {
807: buffer_clear(&compression_buffer);
808: buffer_uncompress(&incoming_packet, &compression_buffer);
809: buffer_clear(&incoming_packet);
810: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
1.25 markus 811: buffer_len(&compression_buffer));
1.14 markus 812: }
813: /* Get packet type. */
814: buffer_get(&incoming_packet, &buf[0], 1);
815:
816: /* Return length of payload (without type field). */
817: *payload_len_ptr = buffer_len(&incoming_packet);
818:
819: /* Return type. */
820: return (unsigned char) buf[0];
1.1 deraadt 821: }
1.14 markus 822:
1.25 markus 823: int
824: packet_read_poll2(int *payload_len_ptr)
825: {
826: unsigned int padlen, need;
827: unsigned char buf[8], *macbuf;
828: unsigned char *ucp;
829: char *cp;
830: static unsigned int packet_length = 0;
831: static unsigned int seqnr = 0;
832: int type;
833: int maclen, block_size;
834: Enc *enc = NULL;
835: Mac *mac = NULL;
836: Comp *comp = NULL;
837:
838: if (kex != NULL) {
839: enc = &kex->enc[MODE_IN];
840: mac = &kex->mac[MODE_IN];
841: comp = &kex->comp[MODE_IN];
842: }
843: maclen = mac && mac->enabled ? mac->mac_len : 0;
844: block_size = enc ? enc->block_size : 8;
845:
846: if (packet_length == 0) {
847: /*
848: * check if input size is less than the cipher block size,
849: * decrypt first block and extract length of incoming packet
850: */
851: if (buffer_len(&input) < block_size)
852: return SSH_MSG_NONE;
853: buffer_clear(&incoming_packet);
854: buffer_append_space(&incoming_packet, &cp, block_size);
855: packet_decrypt(&receive_context, cp, buffer_ptr(&input),
856: block_size);
857: ucp = (unsigned char *) buffer_ptr(&incoming_packet);
858: packet_length = GET_32BIT(ucp);
859: if (packet_length < 1 + 4 || packet_length > 256 * 1024) {
860: buffer_dump(&incoming_packet);
861: packet_disconnect("Bad packet length %d.", packet_length);
862: }
863: DBG(debug("input: packet len %d", packet_length+4));
864: buffer_consume(&input, block_size);
865: }
866: /* we have a partial packet of block_size bytes */
867: need = 4 + packet_length - block_size;
868: DBG(debug("partial packet %d, need %d, maclen %d", block_size,
869: need, maclen));
870: if (need % block_size != 0)
871: fatal("padding error: need %d block %d mod %d",
872: need, block_size, need % block_size);
873: /*
874: * check if the entire packet has been received and
875: * decrypt into incoming_packet
876: */
877: if (buffer_len(&input) < need + maclen)
878: return SSH_MSG_NONE;
879: #ifdef PACKET_DEBUG
880: fprintf(stderr, "read_poll enc/full: ");
881: buffer_dump(&input);
882: #endif
883: buffer_append_space(&incoming_packet, &cp, need);
884: packet_decrypt(&receive_context, cp, buffer_ptr(&input), need);
885: buffer_consume(&input, need);
886: /*
887: * compute MAC over seqnr and packet,
888: * increment sequence number for incoming packet
889: */
1.29 markus 890: if (mac && mac->enabled) {
1.25 markus 891: macbuf = hmac( mac->md, seqnr,
892: (unsigned char *) buffer_ptr(&incoming_packet),
893: buffer_len(&incoming_packet),
894: mac->key, mac->key_len
895: );
896: if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0)
897: packet_disconnect("Corrupted HMAC on input.");
898: DBG(debug("HMAC #%d ok", seqnr));
899: buffer_consume(&input, mac->mac_len);
900: }
1.29 markus 901: if (++seqnr == 0)
902: log("incoming seqnr wraps around");
1.25 markus 903:
904: /* get padlen */
905: cp = buffer_ptr(&incoming_packet) + 4;
906: padlen = *cp & 0xff;
907: DBG(debug("input: padlen %d", padlen));
908: if (padlen < 4)
909: packet_disconnect("Corrupted padlen %d on input.", padlen);
910:
911: /* skip packet size + padlen, discard padding */
912: buffer_consume(&incoming_packet, 4 + 1);
913: buffer_consume_end(&incoming_packet, padlen);
914:
915: DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet)));
916: if (comp && comp->enabled) {
917: buffer_clear(&compression_buffer);
918: buffer_uncompress(&incoming_packet, &compression_buffer);
919: buffer_clear(&incoming_packet);
920: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
921: buffer_len(&compression_buffer));
922: DBG(debug("input: len after de-compress %d", buffer_len(&incoming_packet)));
923: }
924: /*
925: * get packet type, implies consume.
926: * return length of payload (without type field)
927: */
928: buffer_get(&incoming_packet, (char *)&buf[0], 1);
929: *payload_len_ptr = buffer_len(&incoming_packet);
930:
931: /* reset for next packet */
932: packet_length = 0;
933:
934: /* extract packet type */
935: type = (unsigned char)buf[0];
936:
937: if (type == SSH2_MSG_NEWKEYS) {
938: if (kex==NULL || mac==NULL || enc==NULL || comp==NULL)
939: fatal("packet_read_poll2: no KEX");
940: if (mac->md != NULL)
941: mac->enabled = 1;
1.31 markus 942: DBG(debug("cipher_set_key_iv receive_context"));
1.25 markus 943: cipher_set_key_iv(&receive_context, enc->type,
944: enc->key, enc->key_len,
945: enc->iv, enc->iv_len);
946: clear_enc_keys(enc, kex->we_need);
947: if (comp->type != 0 && comp->enabled == 0) {
948: comp->enabled = 1;
949: if (! packet_compression)
950: packet_start_compression(6);
951: }
952: }
953:
954: #ifdef PACKET_DEBUG
955: fprintf(stderr, "read/plain[%d]:\r\n",type);
956: buffer_dump(&incoming_packet);
957: #endif
958: return (unsigned char)type;
959: }
960:
961: int
962: packet_read_poll(int *payload_len_ptr)
963: {
964: char *msg;
965: for (;;) {
966: int type = use_ssh2_packet_format ?
967: packet_read_poll2(payload_len_ptr):
968: packet_read_poll1(payload_len_ptr);
969:
970: if(compat20) {
971: int reason;
972: if (type != 0)
973: DBG(debug("received packet type %d", type));
974: switch(type) {
975: case SSH2_MSG_IGNORE:
976: break;
977: case SSH2_MSG_DEBUG:
978: packet_get_char();
979: msg = packet_get_string(NULL);
980: debug("Remote: %.900s", msg);
981: xfree(msg);
982: msg = packet_get_string(NULL);
983: xfree(msg);
984: break;
985: case SSH2_MSG_DISCONNECT:
986: reason = packet_get_int();
987: msg = packet_get_string(NULL);
988: log("Received disconnect: %d: %.900s", reason, msg);
989: xfree(msg);
990: fatal_cleanup();
991: break;
992: default:
993: return type;
994: break;
995: }
996: } else {
997: switch(type) {
998: case SSH_MSG_IGNORE:
999: break;
1000: case SSH_MSG_DEBUG:
1001: msg = packet_get_string(NULL);
1002: debug("Remote: %.900s", msg);
1003: xfree(msg);
1004: break;
1005: case SSH_MSG_DISCONNECT:
1006: msg = packet_get_string(NULL);
1007: log("Received disconnect: %.900s", msg);
1008: fatal_cleanup();
1009: xfree(msg);
1010: break;
1011: default:
1012: if (type != 0)
1013: DBG(debug("received packet type %d", type));
1014: return type;
1015: break;
1016: }
1017: }
1018: }
1019: }
1020:
1.16 markus 1021: /*
1022: * Buffers the given amount of input characters. This is intended to be used
1023: * together with packet_read_poll.
1024: */
1.1 deraadt 1025:
1.2 provos 1026: void
1027: packet_process_incoming(const char *buf, unsigned int len)
1.1 deraadt 1028: {
1.14 markus 1029: buffer_append(&input, buf, len);
1.1 deraadt 1030: }
1031:
1032: /* Returns a character from the packet. */
1033:
1.2 provos 1034: unsigned int
1035: packet_get_char()
1.1 deraadt 1036: {
1.14 markus 1037: char ch;
1038: buffer_get(&incoming_packet, &ch, 1);
1039: return (unsigned char) ch;
1.1 deraadt 1040: }
1041:
1042: /* Returns an integer from the packet data. */
1043:
1.2 provos 1044: unsigned int
1045: packet_get_int()
1.1 deraadt 1046: {
1.14 markus 1047: return buffer_get_int(&incoming_packet);
1.1 deraadt 1048: }
1049:
1.16 markus 1050: /*
1051: * Returns an arbitrary precision integer from the packet data. The integer
1052: * must have been initialized before this call.
1053: */
1.1 deraadt 1054:
1.2 provos 1055: void
1.14 markus 1056: packet_get_bignum(BIGNUM * value, int *length_ptr)
1.1 deraadt 1057: {
1.14 markus 1058: *length_ptr = buffer_get_bignum(&incoming_packet, value);
1.24 markus 1059: }
1060:
1061: void
1062: packet_get_bignum2(BIGNUM * value, int *length_ptr)
1063: {
1064: *length_ptr = buffer_get_bignum2(&incoming_packet, value);
1065: }
1066:
1067: char *
1068: packet_get_raw(int *length_ptr)
1069: {
1070: int bytes = buffer_len(&incoming_packet);
1071: if (length_ptr != NULL)
1072: *length_ptr = bytes;
1073: return buffer_ptr(&incoming_packet);
1.28 markus 1074: }
1075:
1076: int
1077: packet_remaining(void)
1078: {
1079: return buffer_len(&incoming_packet);
1.1 deraadt 1080: }
1081:
1.16 markus 1082: /*
1083: * Returns a string from the packet data. The string is allocated using
1084: * xmalloc; it is the responsibility of the calling program to free it when
1085: * no longer needed. The length_ptr argument may be NULL, or point to an
1086: * integer into which the length of the string is stored.
1087: */
1.1 deraadt 1088:
1.16 markus 1089: char *
1.14 markus 1090: packet_get_string(unsigned int *length_ptr)
1.1 deraadt 1091: {
1.14 markus 1092: return buffer_get_string(&incoming_packet, length_ptr);
1.1 deraadt 1093: }
1094:
1.16 markus 1095: /*
1096: * Sends a diagnostic message from the server to the client. This message
1097: * can be sent at any time (but not while constructing another message). The
1098: * message is printed immediately, but only if the client is being executed
1099: * in verbose mode. These messages are primarily intended to ease debugging
1100: * authentication problems. The length of the formatted message must not
1101: * exceed 1024 bytes. This will automatically call packet_write_wait.
1102: */
1.1 deraadt 1103:
1.2 provos 1104: void
1.14 markus 1105: packet_send_debug(const char *fmt,...)
1.1 deraadt 1106: {
1.14 markus 1107: char buf[1024];
1108: va_list args;
1109:
1110: va_start(args, fmt);
1111: vsnprintf(buf, sizeof(buf), fmt, args);
1112: va_end(args);
1113:
1.30 markus 1114: if (compat20) {
1115: packet_start(SSH2_MSG_DEBUG);
1116: packet_put_char(0); /* bool: always display */
1117: packet_put_cstring(buf);
1118: packet_put_cstring("");
1119: } else {
1120: packet_start(SSH_MSG_DEBUG);
1121: packet_put_cstring(buf);
1122: }
1.14 markus 1123: packet_send();
1124: packet_write_wait();
1.1 deraadt 1125: }
1126:
1.16 markus 1127: /*
1128: * Logs the error plus constructs and sends a disconnect packet, closes the
1129: * connection, and exits. This function never returns. The error message
1130: * should not contain a newline. The length of the formatted message must
1131: * not exceed 1024 bytes.
1132: */
1.1 deraadt 1133:
1.2 provos 1134: void
1.14 markus 1135: packet_disconnect(const char *fmt,...)
1.1 deraadt 1136: {
1.14 markus 1137: char buf[1024];
1138: va_list args;
1139: static int disconnecting = 0;
1140: if (disconnecting) /* Guard against recursive invocations. */
1141: fatal("packet_disconnect called recursively.");
1142: disconnecting = 1;
1143:
1.16 markus 1144: /*
1145: * Format the message. Note that the caller must make sure the
1146: * message is of limited size.
1147: */
1.14 markus 1148: va_start(args, fmt);
1149: vsnprintf(buf, sizeof(buf), fmt, args);
1150: va_end(args);
1151:
1152: /* Send the disconnect message to the other side, and wait for it to get sent. */
1.25 markus 1153: if (compat20) {
1154: packet_start(SSH2_MSG_DISCONNECT);
1155: packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR);
1156: packet_put_cstring(buf);
1157: packet_put_cstring("");
1158: } else {
1159: packet_start(SSH_MSG_DISCONNECT);
1160: packet_put_string(buf, strlen(buf));
1161: }
1.14 markus 1162: packet_send();
1163: packet_write_wait();
1164:
1165: /* Stop listening for connections. */
1166: channel_stop_listening();
1167:
1168: /* Close the connection. */
1169: packet_close();
1.1 deraadt 1170:
1.14 markus 1171: /* Display the error locally and exit. */
1.17 markus 1172: log("Disconnecting: %.100s", buf);
1173: fatal_cleanup();
1.1 deraadt 1174: }
1175:
1.16 markus 1176: /* Checks if there is any buffered output, and tries to write some of the output. */
1.1 deraadt 1177:
1.2 provos 1178: void
1179: packet_write_poll()
1.1 deraadt 1180: {
1.14 markus 1181: int len = buffer_len(&output);
1182: if (len > 0) {
1183: len = write(connection_out, buffer_ptr(&output), len);
1184: if (len <= 0) {
1185: if (errno == EAGAIN)
1186: return;
1187: else
1188: fatal("Write failed: %.100s", strerror(errno));
1189: }
1190: buffer_consume(&output, len);
1191: }
1.1 deraadt 1192: }
1193:
1.16 markus 1194: /*
1195: * Calls packet_write_poll repeatedly until all pending output data has been
1196: * written.
1197: */
1.1 deraadt 1198:
1.2 provos 1199: void
1200: packet_write_wait()
1.1 deraadt 1201: {
1.14 markus 1202: packet_write_poll();
1203: while (packet_have_data_to_write()) {
1204: fd_set set;
1205: FD_ZERO(&set);
1206: FD_SET(connection_out, &set);
1207: select(connection_out + 1, NULL, &set, NULL, NULL);
1208: packet_write_poll();
1209: }
1.1 deraadt 1210: }
1211:
1212: /* Returns true if there is buffered data to write to the connection. */
1213:
1.2 provos 1214: int
1215: packet_have_data_to_write()
1.1 deraadt 1216: {
1.14 markus 1217: return buffer_len(&output) != 0;
1.1 deraadt 1218: }
1219:
1220: /* Returns true if there is not too much data to write to the connection. */
1221:
1.2 provos 1222: int
1223: packet_not_very_much_data_to_write()
1.1 deraadt 1224: {
1.14 markus 1225: if (interactive_mode)
1226: return buffer_len(&output) < 16384;
1227: else
1228: return buffer_len(&output) < 128 * 1024;
1.1 deraadt 1229: }
1230:
1231: /* Informs that the current session is interactive. Sets IP flags for that. */
1232:
1.2 provos 1233: void
1234: packet_set_interactive(int interactive, int keepalives)
1.1 deraadt 1235: {
1.14 markus 1236: int on = 1;
1.1 deraadt 1237:
1.14 markus 1238: /* Record that we are in interactive mode. */
1239: interactive_mode = interactive;
1.1 deraadt 1240:
1.19 markus 1241: /* Only set socket options if using a socket. */
1242: if (!packet_connection_is_on_socket())
1.14 markus 1243: return;
1244: if (keepalives) {
1245: /* Set keepalives if requested. */
1246: if (setsockopt(connection_in, SOL_SOCKET, SO_KEEPALIVE, (void *) &on,
1.19 markus 1247: sizeof(on)) < 0)
1.14 markus 1248: error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
1249: }
1.19 markus 1250: /*
1251: * IPTOS_LOWDELAY, TCP_NODELAY and IPTOS_THROUGHPUT are IPv4 only
1252: */
1253: if (!packet_connection_is_ipv4())
1254: return;
1.14 markus 1255: if (interactive) {
1.16 markus 1256: /*
1257: * Set IP options for an interactive connection. Use
1258: * IPTOS_LOWDELAY and TCP_NODELAY.
1259: */
1.14 markus 1260: int lowdelay = IPTOS_LOWDELAY;
1261: if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &lowdelay,
1.19 markus 1262: sizeof(lowdelay)) < 0)
1.14 markus 1263: error("setsockopt IPTOS_LOWDELAY: %.100s", strerror(errno));
1264: if (setsockopt(connection_in, IPPROTO_TCP, TCP_NODELAY, (void *) &on,
1.19 markus 1265: sizeof(on)) < 0)
1.14 markus 1266: error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
1267: } else {
1.16 markus 1268: /*
1269: * Set IP options for a non-interactive connection. Use
1270: * IPTOS_THROUGHPUT.
1271: */
1.14 markus 1272: int throughput = IPTOS_THROUGHPUT;
1273: if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &throughput,
1.19 markus 1274: sizeof(throughput)) < 0)
1.14 markus 1275: error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno));
1276: }
1.1 deraadt 1277: }
1278:
1279: /* Returns true if the current connection is interactive. */
1280:
1.2 provos 1281: int
1282: packet_is_interactive()
1.1 deraadt 1283: {
1.14 markus 1284: return interactive_mode;
1.12 markus 1285: }
1286:
1287: int
1288: packet_set_maxsize(int s)
1289: {
1.14 markus 1290: static int called = 0;
1291: if (called) {
1.25 markus 1292: log("packet_set_maxsize: called twice: old %d new %d",
1293: max_packet_size, s);
1.14 markus 1294: return -1;
1295: }
1296: if (s < 4 * 1024 || s > 1024 * 1024) {
1297: log("packet_set_maxsize: bad size %d", s);
1298: return -1;
1299: }
1300: log("packet_set_maxsize: setting to %d", s);
1301: max_packet_size = s;
1302: return s;
1.1 deraadt 1303: }
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