Annotation of src/usr.bin/ssh/packet.c, Revision 1.24
1.1 deraadt 1: /*
1.15 deraadt 2: *
3: * packet.c
4: *
5: * Author: Tatu Ylonen <ylo@cs.hut.fi>
6: *
7: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
8: * All rights reserved
9: *
10: * Created: Sat Mar 18 02:40:40 1995 ylo
11: *
12: * This file contains code implementing the packet protocol and communication
13: * with the other side. This same code is used both on client and server side.
14: *
15: */
1.1 deraadt 16:
17: #include "includes.h"
1.24 ! markus 18: RCSID("$Id: packet.c,v 1.23 2000/03/28 20:31:27 markus Exp $");
1.1 deraadt 19:
20: #include "xmalloc.h"
21: #include "buffer.h"
22: #include "packet.h"
23: #include "bufaux.h"
24: #include "ssh.h"
25: #include "crc32.h"
26: #include "cipher.h"
27: #include "getput.h"
28:
29: #include "compress.h"
1.9 dugsong 30: #include "deattack.h"
1.23 markus 31: #include "channels.h"
1.1 deraadt 32:
1.16 markus 33: /*
34: * This variable contains the file descriptors used for communicating with
35: * the other side. connection_in is used for reading; connection_out for
36: * writing. These can be the same descriptor, in which case it is assumed to
37: * be a socket.
38: */
1.1 deraadt 39: static int connection_in = -1;
40: static int connection_out = -1;
41:
1.16 markus 42: /*
43: * Cipher type. This value is only used to determine whether to pad the
44: * packets with zeroes or random data.
45: */
1.1 deraadt 46: static int cipher_type = SSH_CIPHER_NONE;
47:
48: /* Protocol flags for the remote side. */
49: static unsigned int remote_protocol_flags = 0;
50:
51: /* Encryption context for receiving data. This is only used for decryption. */
52: static CipherContext receive_context;
1.14 markus 53:
54: /* Encryption context for sending data. This is only used for encryption. */
1.1 deraadt 55: static CipherContext send_context;
56:
57: /* Buffer for raw input data from the socket. */
58: static Buffer input;
59:
60: /* Buffer for raw output data going to the socket. */
61: static Buffer output;
62:
63: /* Buffer for the partial outgoing packet being constructed. */
64: static Buffer outgoing_packet;
65:
66: /* Buffer for the incoming packet currently being processed. */
67: static Buffer incoming_packet;
68:
69: /* Scratch buffer for packet compression/decompression. */
70: static Buffer compression_buffer;
71:
72: /* Flag indicating whether packet compression/decompression is enabled. */
73: static int packet_compression = 0;
74:
1.12 markus 75: /* default maximum packet size */
76: int max_packet_size = 32768;
77:
1.1 deraadt 78: /* Flag indicating whether this module has been initialized. */
79: static int initialized = 0;
80:
81: /* Set to true if the connection is interactive. */
82: static int interactive_mode = 0;
83:
1.16 markus 84: /*
85: * Sets the descriptors used for communication. Disables encryption until
86: * packet_set_encryption_key is called.
87: */
1.1 deraadt 88:
1.2 provos 89: void
90: packet_set_connection(int fd_in, int fd_out)
1.1 deraadt 91: {
1.14 markus 92: connection_in = fd_in;
93: connection_out = fd_out;
94: cipher_type = SSH_CIPHER_NONE;
95: cipher_set_key(&send_context, SSH_CIPHER_NONE, (unsigned char *) "", 0, 1);
96: cipher_set_key(&receive_context, SSH_CIPHER_NONE, (unsigned char *) "", 0, 0);
97: if (!initialized) {
98: initialized = 1;
99: buffer_init(&input);
100: buffer_init(&output);
101: buffer_init(&outgoing_packet);
102: buffer_init(&incoming_packet);
103: }
104: /* Kludge: arrange the close function to be called from fatal(). */
105: fatal_add_cleanup((void (*) (void *)) packet_close, NULL);
1.1 deraadt 106: }
107:
1.19 markus 108: /* Returns 1 if remote host is connected via socket, 0 if not. */
109:
110: int
111: packet_connection_is_on_socket()
112: {
113: struct sockaddr_storage from, to;
114: socklen_t fromlen, tolen;
115:
116: /* filedescriptors in and out are the same, so it's a socket */
117: if (connection_in == connection_out)
118: return 1;
119: fromlen = sizeof(from);
120: memset(&from, 0, sizeof(from));
1.20 markus 121: if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0)
1.19 markus 122: return 0;
123: tolen = sizeof(to);
124: memset(&to, 0, sizeof(to));
1.20 markus 125: if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0)
1.19 markus 126: return 0;
127: if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0)
128: return 0;
129: if (from.ss_family != AF_INET && from.ss_family != AF_INET6)
130: return 0;
131: return 1;
132: }
133:
134: /* returns 1 if connection is via ipv4 */
135:
136: int
137: packet_connection_is_ipv4()
138: {
139: struct sockaddr_storage to;
1.21 deraadt 140: socklen_t tolen = sizeof(to);
1.19 markus 141:
142: memset(&to, 0, sizeof(to));
143: if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0)
144: return 0;
145: if (to.ss_family != AF_INET)
146: return 0;
147: return 1;
148: }
149:
1.1 deraadt 150: /* Sets the connection into non-blocking mode. */
151:
1.2 provos 152: void
153: packet_set_nonblocking()
1.1 deraadt 154: {
1.14 markus 155: /* Set the socket into non-blocking mode. */
156: if (fcntl(connection_in, F_SETFL, O_NONBLOCK) < 0)
157: error("fcntl O_NONBLOCK: %.100s", strerror(errno));
158:
159: if (connection_out != connection_in) {
160: if (fcntl(connection_out, F_SETFL, O_NONBLOCK) < 0)
161: error("fcntl O_NONBLOCK: %.100s", strerror(errno));
162: }
1.1 deraadt 163: }
164:
165: /* Returns the socket used for reading. */
166:
1.2 provos 167: int
168: packet_get_connection_in()
1.1 deraadt 169: {
1.14 markus 170: return connection_in;
1.1 deraadt 171: }
172:
173: /* Returns the descriptor used for writing. */
174:
1.2 provos 175: int
176: packet_get_connection_out()
1.1 deraadt 177: {
1.14 markus 178: return connection_out;
1.1 deraadt 179: }
180:
181: /* Closes the connection and clears and frees internal data structures. */
182:
1.2 provos 183: void
184: packet_close()
1.1 deraadt 185: {
1.14 markus 186: if (!initialized)
187: return;
188: initialized = 0;
189: if (connection_in == connection_out) {
190: shutdown(connection_out, SHUT_RDWR);
191: close(connection_out);
192: } else {
193: close(connection_in);
194: close(connection_out);
195: }
196: buffer_free(&input);
197: buffer_free(&output);
198: buffer_free(&outgoing_packet);
199: buffer_free(&incoming_packet);
200: if (packet_compression) {
201: buffer_free(&compression_buffer);
202: buffer_compress_uninit();
203: }
1.1 deraadt 204: }
205:
206: /* Sets remote side protocol flags. */
207:
1.2 provos 208: void
209: packet_set_protocol_flags(unsigned int protocol_flags)
1.1 deraadt 210: {
1.14 markus 211: remote_protocol_flags = protocol_flags;
212: channel_set_options((protocol_flags & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) != 0);
1.1 deraadt 213: }
214:
215: /* Returns the remote protocol flags set earlier by the above function. */
216:
1.2 provos 217: unsigned int
218: packet_get_protocol_flags()
1.1 deraadt 219: {
1.14 markus 220: return remote_protocol_flags;
1.1 deraadt 221: }
222:
1.16 markus 223: /*
224: * Starts packet compression from the next packet on in both directions.
225: * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
226: */
1.1 deraadt 227:
1.2 provos 228: void
229: packet_start_compression(int level)
1.1 deraadt 230: {
1.14 markus 231: if (packet_compression)
232: fatal("Compression already enabled.");
233: packet_compression = 1;
234: buffer_init(&compression_buffer);
235: buffer_compress_init(level);
1.1 deraadt 236: }
237:
1.16 markus 238: /*
239: * Encrypts the given number of bytes, copying from src to dest. bytes is
240: * known to be a multiple of 8.
241: */
1.1 deraadt 242:
1.2 provos 243: void
1.14 markus 244: packet_encrypt(CipherContext * cc, void *dest, void *src,
1.2 provos 245: unsigned int bytes)
1.1 deraadt 246: {
1.14 markus 247: cipher_encrypt(cc, dest, src, bytes);
1.1 deraadt 248: }
249:
1.16 markus 250: /*
251: * Decrypts the given number of bytes, copying from src to dest. bytes is
252: * known to be a multiple of 8.
253: */
1.1 deraadt 254:
1.2 provos 255: void
1.14 markus 256: packet_decrypt(CipherContext * cc, void *dest, void *src,
1.2 provos 257: unsigned int bytes)
1.1 deraadt 258: {
1.14 markus 259: int i;
260:
261: if ((bytes % 8) != 0)
262: fatal("packet_decrypt: bad ciphertext length %d", bytes);
263:
1.16 markus 264: /*
265: * Cryptographic attack detector for ssh - Modifications for packet.c
266: * (C)1998 CORE-SDI, Buenos Aires Argentina Ariel Futoransky(futo@core-sdi.com)
267: */
1.14 markus 268:
269: switch (cc->type) {
270: case SSH_CIPHER_NONE:
271: i = DEATTACK_OK;
272: break;
273: default:
274: i = detect_attack(src, bytes, NULL);
275: break;
276: }
277:
278: if (i == DEATTACK_DETECTED)
279: packet_disconnect("crc32 compensation attack: network attack detected");
280:
281: cipher_decrypt(cc, dest, src, bytes);
1.1 deraadt 282: }
283:
1.16 markus 284: /*
285: * Causes any further packets to be encrypted using the given key. The same
286: * key is used for both sending and reception. However, both directions are
287: * encrypted independently of each other.
288: */
1.1 deraadt 289:
1.2 provos 290: void
291: packet_set_encryption_key(const unsigned char *key, unsigned int keylen,
1.11 markus 292: int cipher)
1.1 deraadt 293: {
1.14 markus 294: /* All other ciphers use the same key in both directions for now. */
295: cipher_set_key(&receive_context, cipher, key, keylen, 0);
296: cipher_set_key(&send_context, cipher, key, keylen, 1);
1.1 deraadt 297: }
298:
299: /* Starts constructing a packet to send. */
300:
1.2 provos 301: void
302: packet_start(int type)
1.1 deraadt 303: {
1.14 markus 304: char buf[9];
1.1 deraadt 305:
1.14 markus 306: buffer_clear(&outgoing_packet);
307: memset(buf, 0, 8);
308: buf[8] = type;
309: buffer_append(&outgoing_packet, buf, 9);
1.1 deraadt 310: }
311:
312: /* Appends a character to the packet data. */
313:
1.2 provos 314: void
315: packet_put_char(int value)
1.1 deraadt 316: {
1.14 markus 317: char ch = value;
318: buffer_append(&outgoing_packet, &ch, 1);
1.1 deraadt 319: }
320:
321: /* Appends an integer to the packet data. */
322:
1.2 provos 323: void
324: packet_put_int(unsigned int value)
1.1 deraadt 325: {
1.14 markus 326: buffer_put_int(&outgoing_packet, value);
1.1 deraadt 327: }
328:
329: /* Appends a string to packet data. */
330:
1.2 provos 331: void
332: packet_put_string(const char *buf, unsigned int len)
1.1 deraadt 333: {
1.14 markus 334: buffer_put_string(&outgoing_packet, buf, len);
1.1 deraadt 335: }
1.24 ! markus 336: void
! 337: packet_put_cstring(const char *str)
! 338: {
! 339: buffer_put_string(&outgoing_packet, str, strlen(str));
! 340: }
! 341:
! 342: void
! 343: packet_put_raw(const char *buf, unsigned int len)
! 344: {
! 345: buffer_append(&outgoing_packet, buf, len);
! 346: }
! 347:
1.1 deraadt 348:
349: /* Appends an arbitrary precision integer to packet data. */
350:
1.2 provos 351: void
1.14 markus 352: packet_put_bignum(BIGNUM * value)
1.1 deraadt 353: {
1.14 markus 354: buffer_put_bignum(&outgoing_packet, value);
1.1 deraadt 355: }
1.24 ! markus 356: void
! 357: packet_put_bignum2(BIGNUM * value)
! 358: {
! 359: buffer_put_bignum2(&outgoing_packet, value);
! 360: }
1.1 deraadt 361:
1.16 markus 362: /*
363: * Finalizes and sends the packet. If the encryption key has been set,
364: * encrypts the packet before sending.
365: */
1.14 markus 366:
1.2 provos 367: void
368: packet_send()
1.1 deraadt 369: {
1.14 markus 370: char buf[8], *cp;
371: int i, padding, len;
372: unsigned int checksum;
373: u_int32_t rand = 0;
374:
1.16 markus 375: /*
376: * If using packet compression, compress the payload of the outgoing
377: * packet.
378: */
1.14 markus 379: if (packet_compression) {
380: buffer_clear(&compression_buffer);
381: /* Skip padding. */
382: buffer_consume(&outgoing_packet, 8);
383: /* padding */
384: buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8);
385: buffer_compress(&outgoing_packet, &compression_buffer);
386: buffer_clear(&outgoing_packet);
387: buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
388: buffer_len(&compression_buffer));
389: }
390: /* Compute packet length without padding (add checksum, remove padding). */
391: len = buffer_len(&outgoing_packet) + 4 - 8;
392:
393: /* Insert padding. */
394: padding = 8 - len % 8;
395: if (cipher_type != SSH_CIPHER_NONE) {
396: cp = buffer_ptr(&outgoing_packet);
397: for (i = 0; i < padding; i++) {
398: if (i % 4 == 0)
399: rand = arc4random();
400: cp[7 - i] = rand & 0xff;
401: rand >>= 8;
402: }
403: }
404: buffer_consume(&outgoing_packet, 8 - padding);
405:
406: /* Add check bytes. */
407: checksum = crc32((unsigned char *) buffer_ptr(&outgoing_packet),
408: buffer_len(&outgoing_packet));
409: PUT_32BIT(buf, checksum);
410: buffer_append(&outgoing_packet, buf, 4);
1.1 deraadt 411:
412: #ifdef PACKET_DEBUG
1.14 markus 413: fprintf(stderr, "packet_send plain: ");
414: buffer_dump(&outgoing_packet);
1.1 deraadt 415: #endif
416:
1.14 markus 417: /* Append to output. */
418: PUT_32BIT(buf, len);
419: buffer_append(&output, buf, 4);
420: buffer_append_space(&output, &cp, buffer_len(&outgoing_packet));
421: packet_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),
422: buffer_len(&outgoing_packet));
423:
1.1 deraadt 424: #ifdef PACKET_DEBUG
1.14 markus 425: fprintf(stderr, "encrypted: ");
426: buffer_dump(&output);
1.1 deraadt 427: #endif
428:
1.14 markus 429: buffer_clear(&outgoing_packet);
1.1 deraadt 430:
1.16 markus 431: /*
432: * Note that the packet is now only buffered in output. It won\'t be
433: * actually sent until packet_write_wait or packet_write_poll is
434: * called.
435: */
1.1 deraadt 436: }
437:
1.16 markus 438: /*
439: * Waits until a packet has been received, and returns its type. Note that
440: * no other data is processed until this returns, so this function should not
441: * be used during the interactive session.
442: */
1.1 deraadt 443:
1.2 provos 444: int
445: packet_read(int *payload_len_ptr)
1.1 deraadt 446: {
1.14 markus 447: int type, len;
448: fd_set set;
449: char buf[8192];
450:
451: /* Since we are blocking, ensure that all written packets have been sent. */
452: packet_write_wait();
453:
454: /* Stay in the loop until we have received a complete packet. */
455: for (;;) {
456: /* Try to read a packet from the buffer. */
457: type = packet_read_poll(payload_len_ptr);
458: if (type == SSH_SMSG_SUCCESS
459: || type == SSH_SMSG_FAILURE
460: || type == SSH_CMSG_EOF
461: || type == SSH_CMSG_EXIT_CONFIRMATION)
462: packet_integrity_check(*payload_len_ptr, 0, type);
463: /* If we got a packet, return it. */
464: if (type != SSH_MSG_NONE)
465: return type;
1.16 markus 466: /*
467: * Otherwise, wait for some data to arrive, add it to the
468: * buffer, and try again.
469: */
1.14 markus 470: FD_ZERO(&set);
471: FD_SET(connection_in, &set);
1.16 markus 472:
1.14 markus 473: /* Wait for some data to arrive. */
474: select(connection_in + 1, &set, NULL, NULL, NULL);
1.16 markus 475:
1.14 markus 476: /* Read data from the socket. */
477: len = read(connection_in, buf, sizeof(buf));
1.18 markus 478: if (len == 0) {
479: log("Connection closed by %.200s", get_remote_ipaddr());
480: fatal_cleanup();
481: }
1.14 markus 482: if (len < 0)
483: fatal("Read from socket failed: %.100s", strerror(errno));
484: /* Append it to the buffer. */
485: packet_process_incoming(buf, len);
486: }
487: /* NOTREACHED */
1.1 deraadt 488: }
489:
1.16 markus 490: /*
491: * Waits until a packet has been received, verifies that its type matches
492: * that given, and gives a fatal error and exits if there is a mismatch.
493: */
1.1 deraadt 494:
1.2 provos 495: void
496: packet_read_expect(int *payload_len_ptr, int expected_type)
1.1 deraadt 497: {
1.14 markus 498: int type;
1.1 deraadt 499:
1.14 markus 500: type = packet_read(payload_len_ptr);
501: if (type != expected_type)
502: packet_disconnect("Protocol error: expected packet type %d, got %d",
503: expected_type, type);
1.1 deraadt 504: }
505:
506: /* Checks if a full packet is available in the data received so far via
1.14 markus 507: * packet_process_incoming. If so, reads the packet; otherwise returns
508: * SSH_MSG_NONE. This does not wait for data from the connection.
509: *
510: * SSH_MSG_DISCONNECT is handled specially here. Also,
511: * SSH_MSG_IGNORE messages are skipped by this function and are never returned
512: * to higher levels.
513: *
514: * The returned payload_len does include space consumed by:
515: * Packet length
516: * Padding
517: * Packet type
518: * Check bytes
519: */
1.1 deraadt 520:
1.2 provos 521: int
522: packet_read_poll(int *payload_len_ptr)
1.1 deraadt 523: {
1.14 markus 524: unsigned int len, padded_len;
525: unsigned char *ucp;
1.22 markus 526: char buf[8], *cp, *msg;
1.14 markus 527: unsigned int checksum, stored_checksum;
528:
529: restart:
530:
531: /* Check if input size is less than minimum packet size. */
532: if (buffer_len(&input) < 4 + 8)
533: return SSH_MSG_NONE;
534: /* Get length of incoming packet. */
535: ucp = (unsigned char *) buffer_ptr(&input);
536: len = GET_32BIT(ucp);
537: if (len < 1 + 2 + 2 || len > 256 * 1024)
538: packet_disconnect("Bad packet length %d.", len);
539: padded_len = (len + 8) & ~7;
540:
541: /* Check if the packet has been entirely received. */
542: if (buffer_len(&input) < 4 + padded_len)
543: return SSH_MSG_NONE;
544:
545: /* The entire packet is in buffer. */
546:
547: /* Consume packet length. */
548: buffer_consume(&input, 4);
549:
550: /* Copy data to incoming_packet. */
551: buffer_clear(&incoming_packet);
552: buffer_append_space(&incoming_packet, &cp, padded_len);
553: packet_decrypt(&receive_context, cp, buffer_ptr(&input), padded_len);
554: buffer_consume(&input, padded_len);
1.1 deraadt 555:
556: #ifdef PACKET_DEBUG
1.14 markus 557: fprintf(stderr, "read_poll plain: ");
558: buffer_dump(&incoming_packet);
1.1 deraadt 559: #endif
560:
1.14 markus 561: /* Compute packet checksum. */
562: checksum = crc32((unsigned char *) buffer_ptr(&incoming_packet),
563: buffer_len(&incoming_packet) - 4);
564:
565: /* Skip padding. */
566: buffer_consume(&incoming_packet, 8 - len % 8);
567:
568: /* Test check bytes. */
569:
570: if (len != buffer_len(&incoming_packet))
571: packet_disconnect("packet_read_poll: len %d != buffer_len %d.",
572: len, buffer_len(&incoming_packet));
573:
574: ucp = (unsigned char *) buffer_ptr(&incoming_packet) + len - 4;
575: stored_checksum = GET_32BIT(ucp);
576: if (checksum != stored_checksum)
577: packet_disconnect("Corrupted check bytes on input.");
578: buffer_consume_end(&incoming_packet, 4);
579:
580: /* If using packet compression, decompress the packet. */
581: if (packet_compression) {
582: buffer_clear(&compression_buffer);
583: buffer_uncompress(&incoming_packet, &compression_buffer);
584: buffer_clear(&incoming_packet);
585: buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
586: buffer_len(&compression_buffer));
587: }
588: /* Get packet type. */
589: buffer_get(&incoming_packet, &buf[0], 1);
590:
591: /* Return length of payload (without type field). */
592: *payload_len_ptr = buffer_len(&incoming_packet);
593:
594: /* Handle disconnect message. */
1.17 markus 595: if ((unsigned char) buf[0] == SSH_MSG_DISCONNECT) {
1.22 markus 596: msg = packet_get_string(NULL);
597: log("Received disconnect: %.900s", msg);
598: xfree(msg);
1.17 markus 599: fatal_cleanup();
600: }
1.14 markus 601:
602: /* Ignore ignore messages. */
603: if ((unsigned char) buf[0] == SSH_MSG_IGNORE)
604: goto restart;
605:
606: /* Send debug messages as debugging output. */
607: if ((unsigned char) buf[0] == SSH_MSG_DEBUG) {
1.22 markus 608: msg = packet_get_string(NULL);
609: debug("Remote: %.900s", msg);
610: xfree(msg);
1.14 markus 611: goto restart;
612: }
613: /* Return type. */
614: return (unsigned char) buf[0];
1.1 deraadt 615: }
1.14 markus 616:
1.16 markus 617: /*
618: * Buffers the given amount of input characters. This is intended to be used
619: * together with packet_read_poll.
620: */
1.1 deraadt 621:
1.2 provos 622: void
623: packet_process_incoming(const char *buf, unsigned int len)
1.1 deraadt 624: {
1.14 markus 625: buffer_append(&input, buf, len);
1.1 deraadt 626: }
627:
628: /* Returns a character from the packet. */
629:
1.2 provos 630: unsigned int
631: packet_get_char()
1.1 deraadt 632: {
1.14 markus 633: char ch;
634: buffer_get(&incoming_packet, &ch, 1);
635: return (unsigned char) ch;
1.1 deraadt 636: }
637:
638: /* Returns an integer from the packet data. */
639:
1.2 provos 640: unsigned int
641: packet_get_int()
1.1 deraadt 642: {
1.14 markus 643: return buffer_get_int(&incoming_packet);
1.1 deraadt 644: }
645:
1.16 markus 646: /*
647: * Returns an arbitrary precision integer from the packet data. The integer
648: * must have been initialized before this call.
649: */
1.1 deraadt 650:
1.2 provos 651: void
1.14 markus 652: packet_get_bignum(BIGNUM * value, int *length_ptr)
1.1 deraadt 653: {
1.14 markus 654: *length_ptr = buffer_get_bignum(&incoming_packet, value);
1.24 ! markus 655: }
! 656:
! 657: void
! 658: packet_get_bignum2(BIGNUM * value, int *length_ptr)
! 659: {
! 660: *length_ptr = buffer_get_bignum2(&incoming_packet, value);
! 661: }
! 662:
! 663: char *
! 664: packet_get_raw(int *length_ptr)
! 665: {
! 666: int bytes = buffer_len(&incoming_packet);
! 667: if (length_ptr != NULL)
! 668: *length_ptr = bytes;
! 669: return buffer_ptr(&incoming_packet);
1.1 deraadt 670: }
671:
1.16 markus 672: /*
673: * Returns a string from the packet data. The string is allocated using
674: * xmalloc; it is the responsibility of the calling program to free it when
675: * no longer needed. The length_ptr argument may be NULL, or point to an
676: * integer into which the length of the string is stored.
677: */
1.1 deraadt 678:
1.16 markus 679: char *
1.14 markus 680: packet_get_string(unsigned int *length_ptr)
1.1 deraadt 681: {
1.14 markus 682: return buffer_get_string(&incoming_packet, length_ptr);
1.1 deraadt 683: }
684:
1.16 markus 685: /*
686: * Sends a diagnostic message from the server to the client. This message
687: * can be sent at any time (but not while constructing another message). The
688: * message is printed immediately, but only if the client is being executed
689: * in verbose mode. These messages are primarily intended to ease debugging
690: * authentication problems. The length of the formatted message must not
691: * exceed 1024 bytes. This will automatically call packet_write_wait.
692: */
1.1 deraadt 693:
1.2 provos 694: void
1.14 markus 695: packet_send_debug(const char *fmt,...)
1.1 deraadt 696: {
1.14 markus 697: char buf[1024];
698: va_list args;
699:
700: va_start(args, fmt);
701: vsnprintf(buf, sizeof(buf), fmt, args);
702: va_end(args);
703:
704: packet_start(SSH_MSG_DEBUG);
705: packet_put_string(buf, strlen(buf));
706: packet_send();
707: packet_write_wait();
1.1 deraadt 708: }
709:
1.16 markus 710: /*
711: * Logs the error plus constructs and sends a disconnect packet, closes the
712: * connection, and exits. This function never returns. The error message
713: * should not contain a newline. The length of the formatted message must
714: * not exceed 1024 bytes.
715: */
1.1 deraadt 716:
1.2 provos 717: void
1.14 markus 718: packet_disconnect(const char *fmt,...)
1.1 deraadt 719: {
1.14 markus 720: char buf[1024];
721: va_list args;
722: static int disconnecting = 0;
723: if (disconnecting) /* Guard against recursive invocations. */
724: fatal("packet_disconnect called recursively.");
725: disconnecting = 1;
726:
1.16 markus 727: /*
728: * Format the message. Note that the caller must make sure the
729: * message is of limited size.
730: */
1.14 markus 731: va_start(args, fmt);
732: vsnprintf(buf, sizeof(buf), fmt, args);
733: va_end(args);
734:
735: /* Send the disconnect message to the other side, and wait for it to get sent. */
736: packet_start(SSH_MSG_DISCONNECT);
737: packet_put_string(buf, strlen(buf));
738: packet_send();
739: packet_write_wait();
740:
741: /* Stop listening for connections. */
742: channel_stop_listening();
743:
744: /* Close the connection. */
745: packet_close();
1.1 deraadt 746:
1.14 markus 747: /* Display the error locally and exit. */
1.17 markus 748: log("Disconnecting: %.100s", buf);
749: fatal_cleanup();
1.1 deraadt 750: }
751:
1.16 markus 752: /* Checks if there is any buffered output, and tries to write some of the output. */
1.1 deraadt 753:
1.2 provos 754: void
755: packet_write_poll()
1.1 deraadt 756: {
1.14 markus 757: int len = buffer_len(&output);
758: if (len > 0) {
759: len = write(connection_out, buffer_ptr(&output), len);
760: if (len <= 0) {
761: if (errno == EAGAIN)
762: return;
763: else
764: fatal("Write failed: %.100s", strerror(errno));
765: }
766: buffer_consume(&output, len);
767: }
1.1 deraadt 768: }
769:
1.16 markus 770: /*
771: * Calls packet_write_poll repeatedly until all pending output data has been
772: * written.
773: */
1.1 deraadt 774:
1.2 provos 775: void
776: packet_write_wait()
1.1 deraadt 777: {
1.14 markus 778: packet_write_poll();
779: while (packet_have_data_to_write()) {
780: fd_set set;
781: FD_ZERO(&set);
782: FD_SET(connection_out, &set);
783: select(connection_out + 1, NULL, &set, NULL, NULL);
784: packet_write_poll();
785: }
1.1 deraadt 786: }
787:
788: /* Returns true if there is buffered data to write to the connection. */
789:
1.2 provos 790: int
791: packet_have_data_to_write()
1.1 deraadt 792: {
1.14 markus 793: return buffer_len(&output) != 0;
1.1 deraadt 794: }
795:
796: /* Returns true if there is not too much data to write to the connection. */
797:
1.2 provos 798: int
799: packet_not_very_much_data_to_write()
1.1 deraadt 800: {
1.14 markus 801: if (interactive_mode)
802: return buffer_len(&output) < 16384;
803: else
804: return buffer_len(&output) < 128 * 1024;
1.1 deraadt 805: }
806:
807: /* Informs that the current session is interactive. Sets IP flags for that. */
808:
1.2 provos 809: void
810: packet_set_interactive(int interactive, int keepalives)
1.1 deraadt 811: {
1.14 markus 812: int on = 1;
1.1 deraadt 813:
1.14 markus 814: /* Record that we are in interactive mode. */
815: interactive_mode = interactive;
1.1 deraadt 816:
1.19 markus 817: /* Only set socket options if using a socket. */
818: if (!packet_connection_is_on_socket())
1.14 markus 819: return;
820: if (keepalives) {
821: /* Set keepalives if requested. */
822: if (setsockopt(connection_in, SOL_SOCKET, SO_KEEPALIVE, (void *) &on,
1.19 markus 823: sizeof(on)) < 0)
1.14 markus 824: error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
825: }
1.19 markus 826: /*
827: * IPTOS_LOWDELAY, TCP_NODELAY and IPTOS_THROUGHPUT are IPv4 only
828: */
829: if (!packet_connection_is_ipv4())
830: return;
1.14 markus 831: if (interactive) {
1.16 markus 832: /*
833: * Set IP options for an interactive connection. Use
834: * IPTOS_LOWDELAY and TCP_NODELAY.
835: */
1.14 markus 836: int lowdelay = IPTOS_LOWDELAY;
837: if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &lowdelay,
1.19 markus 838: sizeof(lowdelay)) < 0)
1.14 markus 839: error("setsockopt IPTOS_LOWDELAY: %.100s", strerror(errno));
840: if (setsockopt(connection_in, IPPROTO_TCP, TCP_NODELAY, (void *) &on,
1.19 markus 841: sizeof(on)) < 0)
1.14 markus 842: error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
843: } else {
1.16 markus 844: /*
845: * Set IP options for a non-interactive connection. Use
846: * IPTOS_THROUGHPUT.
847: */
1.14 markus 848: int throughput = IPTOS_THROUGHPUT;
849: if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &throughput,
1.19 markus 850: sizeof(throughput)) < 0)
1.14 markus 851: error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno));
852: }
1.1 deraadt 853: }
854:
855: /* Returns true if the current connection is interactive. */
856:
1.2 provos 857: int
858: packet_is_interactive()
1.1 deraadt 859: {
1.14 markus 860: return interactive_mode;
1.12 markus 861: }
862:
863: int
864: packet_set_maxsize(int s)
865: {
1.14 markus 866: static int called = 0;
867: if (called) {
868: log("packet_set_maxsize: called twice: old %d new %d", max_packet_size, s);
869: return -1;
870: }
871: if (s < 4 * 1024 || s > 1024 * 1024) {
872: log("packet_set_maxsize: bad size %d", s);
873: return -1;
874: }
875: log("packet_set_maxsize: setting to %d", s);
876: max_packet_size = s;
877: return s;
1.1 deraadt 878: }
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