packet.c revision 99060
1248619Sdes/* 2224638Sbrooks * Author: Tatu Ylonen <ylo@cs.hut.fi> 357429Smarkm * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland 457429Smarkm * All rights reserved 557429Smarkm * This file contains code implementing the packet protocol and communication 657429Smarkm * with the other side. This same code is used both on client and server side. 757429Smarkm * 857429Smarkm * As far as I am concerned, the code I have written for this software 960573Skris * can be used freely for any purpose. Any derived versions of this 1065668Skris * software must be clearly marked as such, and if the derived work is 1165668Skris * incompatible with the protocol description in the RFC file, it must be 1265668Skris * called by a name other than "ssh" or "Secure Shell". 1365668Skris * 1465668Skris * 1565668Skris * SSH2 packet format added by Markus Friedl. 1665668Skris * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. 1760573Skris * 1892555Sdes * Redistribution and use in source and binary forms, with or without 1960573Skris * modification, are permitted provided that the following conditions 2065668Skris * are met: 2165668Skris * 1. Redistributions of source code must retain the above copyright 2265668Skris * notice, this list of conditions and the following disclaimer. 2365668Skris * 2. Redistributions in binary form must reproduce the above copyright 2465668Skris * notice, this list of conditions and the following disclaimer in the 2565668Skris * documentation and/or other materials provided with the distribution. 2665668Skris * 2765668Skris * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 2865668Skris * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 2965668Skris * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 3065668Skris * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 3165668Skris * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 3265668Skris * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 3365668Skris * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 3465668Skris * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 3565668Skris * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 3665668Skris * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 3765668Skris */ 3865668Skris 3957429Smarkm#include "includes.h" 4057429SmarkmRCSID("$OpenBSD: packet.c,v 1.96 2002/06/23 21:10:02 deraadt Exp $"); 4157429Smarkm 42162852Sdes#include "xmalloc.h" 43162852Sdes#include "buffer.h" 44124208Sdes#include "packet.h" 45162852Sdes#include "bufaux.h" 46162852Sdes#include "crc32.h" 47162852Sdes#include "getput.h" 48162852Sdes 49162852Sdes#include "compress.h" 50124208Sdes#include "deattack.h" 51162852Sdes#include "channels.h" 52162852Sdes 53162852Sdes#include "compat.h" 54162852Sdes#include "ssh1.h" 55162852Sdes#include "ssh2.h" 56162852Sdes 57162852Sdes#include "cipher.h" 58162852Sdes#include "kex.h" 59162852Sdes#include "mac.h" 60162852Sdes#include "log.h" 61162852Sdes#include "canohost.h" 62162852Sdes#include "misc.h" 6357429Smarkm#include "ssh.h" 6457429Smarkm 6557429Smarkm#ifdef PACKET_DEBUG 6657429Smarkm#define DBG(x) x 6757429Smarkm#else 6857429Smarkm#define DBG(x) 6960573Skris#endif 7060573Skris 7176259Sgreen/* 7260573Skris * This variable contains the file descriptors used for communicating with 7369587Sgreen * the other side. connection_in is used for reading; connection_out for 74162852Sdes * writing. These can be the same descriptor, in which case it is assumed to 7560573Skris * be a socket. 7676259Sgreen */ 7776259Sgreenstatic int connection_in = -1; 7876259Sgreenstatic int connection_out = -1; 7992555Sdes 8098675Sdes/* Protocol flags for the remote side. */ 81197679Sdesstatic u_int remote_protocol_flags = 0; 8260573Skris 8360573Skris/* Encryption context for receiving data. This is only used for decryption. */ 8460573Skrisstatic CipherContext receive_context; 8560573Skris 8660573Skris/* Encryption context for sending data. This is only used for encryption. */ 8760573Skrisstatic CipherContext send_context; 8860573Skris 89192595Sdes/* Buffer for raw input data from the socket. */ 90192595SdesBuffer input; 91197679Sdes 92197679Sdes/* Buffer for raw output data going to the socket. */ 93197679SdesBuffer output; 94197679Sdes 95197679Sdes/* Buffer for the partial outgoing packet being constructed. */ 96197679Sdesstatic Buffer outgoing_packet; 9757429Smarkm 98197679Sdes/* Buffer for the incoming packet currently being processed. */ 99197679Sdesstatic Buffer incoming_packet; 100197679Sdes 101197679Sdes/* Scratch buffer for packet compression/decompression. */ 102197679Sdesstatic Buffer compression_buffer; 10357429Smarkmstatic int compression_buffer_ready = 0; 104197679Sdes 105197679Sdes/* Flag indicating whether packet compression/decompression is enabled. */ 106197679Sdesstatic int packet_compression = 0; 107197679Sdes 108197679Sdes/* default maximum packet size */ 109197679Sdesint max_packet_size = 32768; 110197679Sdes 111197679Sdes/* Flag indicating whether this module has been initialized. */ 112197679Sdesstatic int initialized = 0; 11357429Smarkm 114197679Sdes/* Set to true if the connection is interactive. */ 115197679Sdesstatic int interactive_mode = 0; 11657429Smarkm 117197679Sdes/* Session key information for Encryption and MAC */ 118197679SdesNewkeys *newkeys[MODE_MAX]; 11957429Smarkmstatic u_int32_t read_seqnr = 0; 120197679Sdesstatic u_int32_t send_seqnr = 0; 121197679Sdes 12257429Smarkm/* Session key for protocol v1 */ 123197679Sdesstatic u_char ssh1_key[SSH_SESSION_KEY_LENGTH]; 124197679Sdesstatic u_int ssh1_keylen; 12557429Smarkm 126197679Sdes/* roundup current message to extra_pad bytes */ 127197679Sdesstatic u_char extra_pad = 0; 12857429Smarkm 129197679Sdes/* 130197679Sdes * Sets the descriptors used for communication. Disables encryption until 13157429Smarkm * packet_set_encryption_key is called. 132197679Sdes */ 133197679Sdesvoid 13457429Smarkmpacket_set_connection(int fd_in, int fd_out) 135197679Sdes{ 136197679Sdes Cipher *none = cipher_by_name("none"); 137197679Sdes if (none == NULL) 13857429Smarkm fatal("packet_set_connection: cannot load cipher 'none'"); 139197679Sdes connection_in = fd_in; 140197679Sdes connection_out = fd_out; 141197679Sdes cipher_init(&send_context, none, "", 0, NULL, 0, CIPHER_ENCRYPT); 142197679Sdes cipher_init(&receive_context, none, "", 0, NULL, 0, CIPHER_DECRYPT); 143197679Sdes newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL; 14457429Smarkm if (!initialized) { 145197679Sdes initialized = 1; 146197679Sdes buffer_init(&input); 14757429Smarkm buffer_init(&output); 148197679Sdes buffer_init(&outgoing_packet); 149197679Sdes buffer_init(&incoming_packet); 150149749Sdes } 151197679Sdes /* Kludge: arrange the close function to be called from fatal(). */ 152197679Sdes fatal_add_cleanup((void (*) (void *)) packet_close, NULL); 153149749Sdes} 154197679Sdes 155197679Sdes/* Returns 1 if remote host is connected via socket, 0 if not. */ 156181111Sdes 157197679Sdesint 158197679Sdespacket_connection_is_on_socket(void) 159181111Sdes{ 160197679Sdes struct sockaddr_storage from, to; 16160573Skris socklen_t fromlen, tolen; 162197679Sdes 163197679Sdes /* filedescriptors in and out are the same, so it's a socket */ 164124208Sdes if (connection_in == connection_out) 165197679Sdes return 1; 166197679Sdes fromlen = sizeof(from); 167197679Sdes memset(&from, 0, sizeof(from)); 16898675Sdes if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0) 169197679Sdes return 0; 170197679Sdes tolen = sizeof(to); 17160573Skris memset(&to, 0, sizeof(to)); 172197679Sdes if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0) 173197679Sdes return 0; 174197679Sdes if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0) 175192595Sdes return 0; 176197679Sdes if (from.ss_family != AF_INET && from.ss_family != AF_INET6) 177197679Sdes return 0; 178197679Sdes return 1; 179197679Sdes} 180197679Sdes 181197679Sdes/* 182197679Sdes * Exports an IV from the CipherContext required to export the key 183197679Sdes * state back from the unprivileged child to the privileged parent 184197679Sdes * process. 185197679Sdes */ 186197679Sdes 187197679Sdesvoid 188197679Sdespacket_get_keyiv(int mode, u_char *iv, u_int len) 189197679Sdes{ 190197679Sdes CipherContext *cc; 191197679Sdes 192197679Sdes if (mode == MODE_OUT) 193197679Sdes cc = &send_context; 194197679Sdes else 195197679Sdes cc = &receive_context; 196124208Sdes 197124208Sdes cipher_get_keyiv(cc, iv, len); 198197679Sdes} 199224638Sbrooks 200224638Sbrooksint 201224638Sbrookspacket_get_keycontext(int mode, u_char *dat) 202197679Sdes{ 203197679Sdes CipherContext *cc; 204197679Sdes 205197679Sdes if (mode == MODE_OUT) 206221420Sdes cc = &send_context; 207197679Sdes else 208221420Sdes cc = &receive_context; 209221420Sdes 210221420Sdes return (cipher_get_keycontext(cc, dat)); 211221420Sdes} 212221420Sdes 213197679Sdesvoid 214197679Sdespacket_set_keycontext(int mode, u_char *dat) 21557429Smarkm{ 21657429Smarkm CipherContext *cc; 21757429Smarkm 21857429Smarkm if (mode == MODE_OUT) 21957429Smarkm cc = &send_context; 22057429Smarkm else 22157429Smarkm cc = &receive_context; 22269587Sgreen 223106121Sdes cipher_set_keycontext(cc, dat); 22469587Sgreen} 22569587Sgreen 226197679Sdesint 227197679Sdespacket_get_keyiv_len(int mode) 228197679Sdes{ 229197679Sdes CipherContext *cc; 230197679Sdes 231137015Sdes if (mode == MODE_OUT) 232197679Sdes cc = &send_context; 233137015Sdes else 234197679Sdes cc = &receive_context; 235197679Sdes 236197679Sdes return (cipher_get_keyiv_len(cc)); 237197679Sdes} 238197679Sdesvoid 239197679Sdespacket_set_iv(int mode, u_char *dat) 240197679Sdes{ 241197679Sdes CipherContext *cc; 242197679Sdes 24357429Smarkm if (mode == MODE_OUT) 24457429Smarkm cc = &send_context; 24557429Smarkm else 246181111Sdes cc = &receive_context; 247181111Sdes 248181111Sdes cipher_set_keyiv(cc, dat); 249240075Sdes} 250197679Sdesint 251181111Sdespacket_get_ssh1_cipher() 252181111Sdes{ 253181111Sdes return (cipher_get_number(receive_context.cipher)); 254197679Sdes} 255181111Sdes 256197679Sdes 257181111Sdesu_int32_t 258181111Sdespacket_get_seqnr(int mode) 259192595Sdes{ 260192595Sdes return (mode == MODE_IN ? read_seqnr : send_seqnr); 261192595Sdes} 262197679Sdes 263192595Sdesvoid 264192595Sdespacket_set_seqnr(int mode, u_int32_t seqnr) 265192595Sdes{ 266197679Sdes if (mode == MODE_IN) 267197679Sdes read_seqnr = seqnr; 268197679Sdes else if (mode == MODE_OUT) 269197679Sdes send_seqnr = seqnr; 270197679Sdes else 271197679Sdes fatal("packet_set_seqnr: bad mode %d", mode); 272197679Sdes} 273192595Sdes 274192595Sdes/* returns 1 if connection is via ipv4 */ 275192595Sdes 276192595Sdesint 277192595Sdespacket_connection_is_ipv4(void) 278192595Sdes{ 279192595Sdes struct sockaddr_storage to; 280192595Sdes socklen_t tolen = sizeof(to); 281192595Sdes 282248619Sdes memset(&to, 0, sizeof(to)); 283192595Sdes if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0) 284192595Sdes return 0; 285197679Sdes if (to.ss_family == AF_INET) 286197679Sdes return 1; 287192595Sdes#ifdef IPV4_IN_IPV6 288197679Sdes if (to.ss_family == AF_INET6 && 289197679Sdes IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&to)->sin6_addr)) 290192595Sdes return 1; 291192595Sdes#endif 29257429Smarkm return 0; 29357429Smarkm} 29457429Smarkm 29592555Sdes/* Sets the connection into non-blocking mode. */ 29657429Smarkm 29757429Smarkmvoid 29857429Smarkmpacket_set_nonblocking(void) 29957429Smarkm{ 30057429Smarkm /* Set the socket into non-blocking mode. */ 301197679Sdes if (fcntl(connection_in, F_SETFL, O_NONBLOCK) < 0) 30257429Smarkm error("fcntl O_NONBLOCK: %.100s", strerror(errno)); 30357429Smarkm 30457429Smarkm if (connection_out != connection_in) { 305197679Sdes if (fcntl(connection_out, F_SETFL, O_NONBLOCK) < 0) 306197679Sdes error("fcntl O_NONBLOCK: %.100s", strerror(errno)); 30757429Smarkm } 30857429Smarkm} 30957429Smarkm 310197679Sdes/* Returns the socket used for reading. */ 311197679Sdes 31257429Smarkmint 31357429Smarkmpacket_get_connection_in(void) 31457429Smarkm{ 31557429Smarkm return connection_in; 31657429Smarkm} 31757429Smarkm 31857429Smarkm/* Returns the descriptor used for writing. */ 31957429Smarkm 32098675Sdesint 32198675Sdespacket_get_connection_out(void) 32298675Sdes{ 32398675Sdes return connection_out; 32498675Sdes} 32598675Sdes 32698675Sdes/* Closes the connection and clears and frees internal data structures. */ 32798675Sdes 32898675Sdesvoid 32998675Sdespacket_close(void) 33098675Sdes{ 33198675Sdes if (!initialized) 332197679Sdes return; 33398675Sdes initialized = 0; 334197679Sdes if (connection_in == connection_out) { 33598675Sdes shutdown(connection_out, SHUT_RDWR); 33698675Sdes close(connection_out); 33798675Sdes } else { 33898675Sdes close(connection_in); 33998675Sdes close(connection_out); 34098675Sdes } 34198675Sdes buffer_free(&input); 34298675Sdes buffer_free(&output); 34398675Sdes buffer_free(&outgoing_packet); 34498675Sdes buffer_free(&incoming_packet); 345197679Sdes if (compression_buffer_ready) { 34698675Sdes buffer_free(&compression_buffer); 347197679Sdes buffer_compress_uninit(); 34898675Sdes } 34998675Sdes cipher_cleanup(&send_context); 35098675Sdes cipher_cleanup(&receive_context); 35198675Sdes} 35298675Sdes 35398675Sdes/* Sets remote side protocol flags. */ 35498675Sdes 35598675Sdesvoid 35698675Sdespacket_set_protocol_flags(u_int protocol_flags) 35798675Sdes{ 358197679Sdes remote_protocol_flags = protocol_flags; 35998675Sdes} 360197679Sdes 36198675Sdes/* Returns the remote protocol flags set earlier by the above function. */ 36298675Sdes 36398675Sdesu_int 36498675Sdespacket_get_protocol_flags(void) 36598675Sdes{ 36698675Sdes return remote_protocol_flags; 36798675Sdes} 36898675Sdes 36998675Sdes/* 37098675Sdes * Starts packet compression from the next packet on in both directions. 371197679Sdes * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. 37298675Sdes */ 373197679Sdes 37498675Sdesstatic void 37598675Sdespacket_init_compression(void) 37698675Sdes{ 377162852Sdes if (compression_buffer_ready == 1) 37898675Sdes return; 37998675Sdes compression_buffer_ready = 1; 38098675Sdes buffer_init(&compression_buffer); 38198675Sdes} 38298675Sdes 38398675Sdesvoid 384197679Sdespacket_start_compression(int level) 38598675Sdes{ 386197679Sdes if (packet_compression && !compat20) 38798675Sdes fatal("Compression already enabled."); 38898675Sdes packet_compression = 1; 38998675Sdes packet_init_compression(); 390162852Sdes buffer_compress_init_send(level); 39198675Sdes buffer_compress_init_recv(); 392124208Sdes} 39398675Sdes 394197679Sdes/* 39598675Sdes * Causes any further packets to be encrypted using the given key. The same 39698675Sdes * key is used for both sending and reception. However, both directions are 397124208Sdes * encrypted independently of each other. 398221420Sdes */ 399221420Sdes 400124208Sdesvoid 401124208Sdespacket_set_encryption_key(const u_char *key, u_int keylen, 40298675Sdes int number) 403197679Sdes{ 404197679Sdes Cipher *cipher = cipher_by_number(number); 405181111Sdes if (cipher == NULL) 406181111Sdes fatal("packet_set_encryption_key: unknown cipher number %d", number); 407181111Sdes if (keylen < 20) 408181111Sdes fatal("packet_set_encryption_key: keylen too small: %d", keylen); 409181111Sdes if (keylen > SSH_SESSION_KEY_LENGTH) 410181111Sdes fatal("packet_set_encryption_key: keylen too big: %d", keylen); 411181111Sdes memcpy(ssh1_key, key, keylen); 412181111Sdes ssh1_keylen = keylen; 41398675Sdes cipher_init(&send_context, cipher, key, keylen, NULL, 0, CIPHER_ENCRYPT); 41498675Sdes cipher_init(&receive_context, cipher, key, keylen, NULL, 0, CIPHER_DECRYPT); 41598675Sdes} 416181111Sdes 417181111Sdesu_int 41898675Sdespacket_get_encryption_key(u_char *key) 419124208Sdes{ 420124208Sdes if (key == NULL) 421197679Sdes return (ssh1_keylen); 422197679Sdes memcpy(key, ssh1_key, ssh1_keylen); 423124208Sdes return (ssh1_keylen); 424124208Sdes} 425124208Sdes 426181111Sdes/* Start constructing a packet to send. */ 42798675Sdesvoid 42898675Sdespacket_start(u_char type) 429226046Sdes{ 430226046Sdes u_char buf[9]; 43157429Smarkm int len; 43257429Smarkm 43357429Smarkm DBG(debug("packet_start[%d]", type)); 43457429Smarkm len = compat20 ? 6 : 9; 43557429Smarkm memset(buf, 0, len - 1); 436197679Sdes buf[len - 1] = type; 437197679Sdes buffer_clear(&outgoing_packet); 43857429Smarkm buffer_append(&outgoing_packet, buf, len); 43998937Sdes} 440126274Sdes 44198937Sdes/* Append payload. */ 442226046Sdesvoid 44398937Sdespacket_put_char(int value) 444226046Sdes{ 44557429Smarkm char ch = value; 44657429Smarkm buffer_append(&outgoing_packet, &ch, 1); 44757429Smarkm} 44857429Smarkmvoid 44957429Smarkmpacket_put_int(u_int value) 45092555Sdes{ 45157429Smarkm buffer_put_int(&outgoing_packet, value); 45257429Smarkm} 453197679Sdesvoid 45457429Smarkmpacket_put_string(const void *buf, u_int len) 455197679Sdes{ 456197679Sdes buffer_put_string(&outgoing_packet, buf, len); 45757429Smarkm} 45857429Smarkmvoid 45957429Smarkmpacket_put_cstring(const char *str) 46057429Smarkm{ 46157429Smarkm buffer_put_cstring(&outgoing_packet, str); 46292555Sdes} 46357429Smarkmvoid 464197679Sdespacket_put_raw(const void *buf, u_int len) 46557429Smarkm{ 46657429Smarkm buffer_append(&outgoing_packet, buf, len); 46757429Smarkm} 46857429Smarkmvoid 46957429Smarkmpacket_put_bignum(BIGNUM * value) 47092555Sdes{ 47157429Smarkm buffer_put_bignum(&outgoing_packet, value); 472197679Sdes} 47357429Smarkmvoid 47457429Smarkmpacket_put_bignum2(BIGNUM * value) 47557429Smarkm{ 47657429Smarkm buffer_put_bignum2(&outgoing_packet, value); 47757429Smarkm} 47892555Sdes 47957429Smarkm/* 480197679Sdes * Finalizes and sends the packet. If the encryption key has been set, 48157429Smarkm * encrypts the packet before sending. 482197679Sdes */ 483197679Sdes 484197679Sdesstatic void 485197679Sdespacket_send1(void) 48657429Smarkm{ 487197679Sdes u_char buf[8], *cp; 488197679Sdes int i, padding, len; 48957429Smarkm u_int checksum; 490197679Sdes u_int32_t rand = 0; 491197679Sdes 492197679Sdes /* 493197679Sdes * If using packet compression, compress the payload of the outgoing 494197679Sdes * packet. 495197679Sdes */ 49657429Smarkm if (packet_compression) { 49757429Smarkm buffer_clear(&compression_buffer); 498197679Sdes /* Skip padding. */ 499197679Sdes buffer_consume(&outgoing_packet, 8); 50057429Smarkm /* padding */ 50157429Smarkm buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8); 50257429Smarkm buffer_compress(&outgoing_packet, &compression_buffer); 50357429Smarkm buffer_clear(&outgoing_packet); 50457429Smarkm buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer), 50576259Sgreen buffer_len(&compression_buffer)); 50657429Smarkm } 507197679Sdes /* Compute packet length without padding (add checksum, remove padding). */ 50857429Smarkm len = buffer_len(&outgoing_packet) + 4 - 8; 50957429Smarkm 51057429Smarkm /* Insert padding. Initialized to zero in packet_start1() */ 51157429Smarkm padding = 8 - len % 8; 51276259Sgreen if (!send_context.plaintext) { 51392555Sdes cp = buffer_ptr(&outgoing_packet); 51457429Smarkm for (i = 0; i < padding; i++) { 515197679Sdes if (i % 4 == 0) 51657429Smarkm rand = arc4random(); 51757429Smarkm cp[7 - i] = rand & 0xff; 51857429Smarkm rand >>= 8; 51957429Smarkm } 52057429Smarkm } 52157429Smarkm buffer_consume(&outgoing_packet, 8 - padding); 52257429Smarkm 52392555Sdes /* Add check bytes. */ 52492555Sdes checksum = ssh_crc32(buffer_ptr(&outgoing_packet), 52576259Sgreen buffer_len(&outgoing_packet)); 526197679Sdes PUT_32BIT(buf, checksum); 52776259Sgreen buffer_append(&outgoing_packet, buf, 4); 528197679Sdes 529197679Sdes#ifdef PACKET_DEBUG 53076259Sgreen fprintf(stderr, "packet_send plain: "); 53176259Sgreen buffer_dump(&outgoing_packet); 53276259Sgreen#endif 53357429Smarkm 53457429Smarkm /* Append to output. */ 535197679Sdes PUT_32BIT(buf, len); 53657429Smarkm buffer_append(&output, buf, 4); 537197679Sdes cp = buffer_append_space(&output, buffer_len(&outgoing_packet)); 53876259Sgreen cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet), 53976259Sgreen buffer_len(&outgoing_packet)); 54076259Sgreen 54157429Smarkm#ifdef PACKET_DEBUG 54257429Smarkm fprintf(stderr, "encrypted: "); 54357429Smarkm buffer_dump(&output); 54457429Smarkm#endif 54557429Smarkm 54657429Smarkm buffer_clear(&outgoing_packet); 54757429Smarkm 54898675Sdes /* 54957429Smarkm * Note that the packet is now only buffered in output. It won\'t be 550221420Sdes * actually sent until packet_write_wait or packet_write_poll is 55157429Smarkm * called. 55269587Sgreen */ 553106121Sdes} 55469587Sgreen 55569587Sgreenvoid 55660573Skrisset_newkeys(int mode) 55769587Sgreen{ 55898675Sdes Enc *enc; 55998675Sdes Mac *mac; 560197679Sdes Comp *comp; 561197679Sdes CipherContext *cc; 562197679Sdes int encrypt; 563197679Sdes 564197679Sdes debug("newkeys: mode %d", mode); 565197679Sdes 56657429Smarkm if (mode == MODE_OUT) { 56757429Smarkm cc = &send_context; 56898675Sdes encrypt = CIPHER_ENCRYPT; 56998675Sdes } else { 57098675Sdes cc = &receive_context; 57198675Sdes encrypt = CIPHER_DECRYPT; 572197679Sdes } 573197679Sdes if (newkeys[mode] != NULL) { 574197679Sdes debug("newkeys: rekeying"); 57598675Sdes cipher_cleanup(cc); 57698675Sdes enc = &newkeys[mode]->enc; 57792555Sdes mac = &newkeys[mode]->mac; 57857429Smarkm comp = &newkeys[mode]->comp; 57992555Sdes memset(mac->key, 0, mac->key_len); 58057429Smarkm xfree(enc->name); 58192555Sdes xfree(enc->iv); 58292555Sdes xfree(enc->key); 58357429Smarkm xfree(mac->name); 58492555Sdes xfree(mac->key); 58592555Sdes xfree(comp->name); 58692555Sdes xfree(newkeys[mode]); 58792555Sdes } 588197679Sdes newkeys[mode] = kex_get_newkeys(mode); 589197679Sdes if (newkeys[mode] == NULL) 59057429Smarkm fatal("newkeys: no keys for mode %d", mode); 59157429Smarkm enc = &newkeys[mode]->enc; 59292555Sdes mac = &newkeys[mode]->mac; 59360573Skris comp = &newkeys[mode]->comp; 59457429Smarkm if (mac->md != NULL) 59557429Smarkm mac->enabled = 1; 59657429Smarkm DBG(debug("cipher_init_context: %d", mode)); 597106121Sdes cipher_init(cc, enc->cipher, enc->key, enc->key_len, 598197679Sdes enc->iv, enc->block_size, encrypt); 59957429Smarkm /* Deleting the keys does not gain extra security */ 600162852Sdes /* memset(enc->iv, 0, enc->block_size); 60157429Smarkm memset(enc->key, 0, enc->key_len); */ 60276259Sgreen if (comp->type != 0 && comp->enabled == 0) { 60357429Smarkm packet_init_compression(); 604197679Sdes if (mode == MODE_OUT) 60557429Smarkm buffer_compress_init_send(6); 606162852Sdes else 60757429Smarkm buffer_compress_init_recv(); 608197679Sdes comp->enabled = 1; 609197679Sdes } 610197679Sdes} 611197679Sdes 612197679Sdes/* 613197679Sdes * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) 61492555Sdes */ 61557429Smarkmstatic void 616197679Sdespacket_send2(void) 61757429Smarkm{ 618162852Sdes u_char type, *cp, *macbuf = NULL; 61960573Skris u_char padlen, pad; 62060573Skris u_int packet_length = 0; 62160573Skris u_int i, len; 622197679Sdes u_int32_t rand = 0; 62360573Skris Enc *enc = NULL; 624162852Sdes Mac *mac = NULL; 62560573Skris Comp *comp = NULL; 62692555Sdes int block_size; 62760573Skris 628197679Sdes if (newkeys[MODE_OUT] != NULL) { 62960573Skris enc = &newkeys[MODE_OUT]->enc; 630162852Sdes mac = &newkeys[MODE_OUT]->mac; 63157429Smarkm comp = &newkeys[MODE_OUT]->comp; 63257429Smarkm } 63357429Smarkm block_size = enc ? enc->block_size : 8; 634197679Sdes 63557429Smarkm cp = buffer_ptr(&outgoing_packet); 636162852Sdes type = cp[5]; 63760573Skris 63860573Skris#ifdef PACKET_DEBUG 63960573Skris fprintf(stderr, "plain: "); 640197679Sdes buffer_dump(&outgoing_packet); 64160573Skris#endif 64257429Smarkm 643221420Sdes if (comp && comp->enabled) { 644221420Sdes len = buffer_len(&outgoing_packet); 645221420Sdes /* skip header, compress only payload */ 646221420Sdes buffer_consume(&outgoing_packet, 5); 647221420Sdes buffer_clear(&compression_buffer); 648221420Sdes buffer_compress(&outgoing_packet, &compression_buffer); 649221420Sdes buffer_clear(&outgoing_packet); 650221420Sdes buffer_append(&outgoing_packet, "\0\0\0\0\0", 5); 65157429Smarkm buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer), 65257429Smarkm buffer_len(&compression_buffer)); 65357429Smarkm DBG(debug("compression: raw %d compressed %d", len, 65457429Smarkm buffer_len(&outgoing_packet))); 65557429Smarkm } 65692555Sdes 65776259Sgreen /* sizeof (packet_len + pad_len + payload) */ 65857429Smarkm len = buffer_len(&outgoing_packet); 65992555Sdes 66057429Smarkm /* 66176259Sgreen * calc size of padding, alloc space, get random data, 662137015Sdes * minimum padding is 4 bytes 66357429Smarkm */ 66457429Smarkm padlen = block_size - (len % block_size); 66557429Smarkm if (padlen < 4) 66657429Smarkm padlen += block_size; 66757429Smarkm if (extra_pad) { 668197679Sdes /* will wrap if extra_pad+padlen > 255 */ 669197679Sdes extra_pad = roundup(extra_pad, block_size); 67057429Smarkm pad = extra_pad - ((len + padlen) % extra_pad); 671197679Sdes debug3("packet_send2: adding %d (len %d padlen %d extra_pad %d)", 67257429Smarkm pad, len, padlen, extra_pad); 673197679Sdes padlen += pad; 674197679Sdes extra_pad = 0; 675197679Sdes } 676197679Sdes cp = buffer_append_space(&outgoing_packet, padlen); 677197679Sdes if (enc && !send_context.plaintext) { 678197679Sdes /* random padding */ 679197679Sdes for (i = 0; i < padlen; i++) { 680197679Sdes if (i % 4 == 0) 68157429Smarkm rand = arc4random(); 68257429Smarkm cp[i] = rand & 0xff; 683197679Sdes rand >>= 8; 68457429Smarkm } 68560573Skris } else { 68657429Smarkm /* clear padding */ 687197679Sdes memset(cp, 0, padlen); 688197679Sdes } 68957429Smarkm /* packet_length includes payload, padding and padding length field */ 69057429Smarkm packet_length = buffer_len(&outgoing_packet) - 4; 691137015Sdes cp = buffer_ptr(&outgoing_packet); 692137015Sdes PUT_32BIT(cp, packet_length); 693137015Sdes cp[4] = padlen; 69457429Smarkm DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen)); 69557429Smarkm 696197679Sdes /* compute MAC over seqnr and packet(length fields, payload, padding) */ 69757429Smarkm if (mac && mac->enabled) { 69857429Smarkm macbuf = mac_compute(mac, send_seqnr, 699197679Sdes buffer_ptr(&outgoing_packet), 700197679Sdes buffer_len(&outgoing_packet)); 701162852Sdes DBG(debug("done calc MAC out #%d", send_seqnr)); 702197679Sdes } 70357429Smarkm /* encrypt packet and append to output buffer. */ 70457429Smarkm cp = buffer_append_space(&output, buffer_len(&outgoing_packet)); 70557429Smarkm cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet), 706197679Sdes buffer_len(&outgoing_packet)); 70757429Smarkm /* append unencrypted MAC */ 70857429Smarkm if (mac && mac->enabled) 70957429Smarkm buffer_append(&output, (char *)macbuf, mac->mac_len); 710162852Sdes#ifdef PACKET_DEBUG 711197679Sdes fprintf(stderr, "encrypted: "); 712197679Sdes buffer_dump(&output); 713197679Sdes#endif 714197679Sdes /* increment sequence number for outgoing packets */ 715197679Sdes if (++send_seqnr == 0) 716248619Sdes log("outgoing seqnr wraps around"); 71757429Smarkm buffer_clear(&outgoing_packet); 71857429Smarkm 71957429Smarkm if (type == SSH2_MSG_NEWKEYS) 720197679Sdes set_newkeys(MODE_OUT); 72157429Smarkm} 722197679Sdes 723197679Sdesvoid 724197679Sdespacket_send(void) 725197679Sdes{ 72657429Smarkm if (compat20) 72757429Smarkm packet_send2(); 728157016Sdes else 72957429Smarkm packet_send1(); 73057429Smarkm DBG(debug("packet_send done")); 73157429Smarkm} 73257429Smarkm 73357429Smarkm/* 73498675Sdes * Waits until a packet has been received, and returns its type. Note that 73576259Sgreen * no other data is processed until this returns, so this function should not 73676259Sgreen * be used during the interactive session. 73776259Sgreen */ 73876259Sgreen 73976259Sgreenint 74076259Sgreenpacket_read_seqnr(u_int32_t *seqnr_p) 741124208Sdes{ 742137015Sdes int type, len; 74376259Sgreen fd_set *setp; 744113908Sdes char buf[8192]; 74576259Sgreen DBG(debug("packet_read()")); 74692555Sdes 747197679Sdes setp = (fd_set *)xmalloc(howmany(connection_in+1, NFDBITS) * 748137015Sdes sizeof(fd_mask)); 749197679Sdes 750197679Sdes /* Since we are blocking, ensure that all written packets have been sent. */ 75192555Sdes packet_write_wait(); 752197679Sdes 753137015Sdes /* Stay in the loop until we have received a complete packet. */ 754197679Sdes for (;;) { 755197679Sdes /* Try to read a packet from the buffer. */ 75692555Sdes type = packet_read_poll_seqnr(seqnr_p); 757197679Sdes if (!compat20 && ( 758113908Sdes type == SSH_SMSG_SUCCESS 75992555Sdes || type == SSH_SMSG_FAILURE 760197679Sdes || type == SSH_CMSG_EOF 761197679Sdes || type == SSH_CMSG_EXIT_CONFIRMATION)) 762197679Sdes packet_check_eom(); 763181111Sdes /* If we got a packet, return it. */ 764248619Sdes if (type != SSH_MSG_NONE) { 765248619Sdes xfree(setp); 766248619Sdes return type; 76776259Sgreen } 76876259Sgreen /* 76976259Sgreen * Otherwise, wait for some data to arrive, add it to the 77076259Sgreen * buffer, and try again. 77176259Sgreen */ 77276259Sgreen memset(setp, 0, howmany(connection_in + 1, NFDBITS) * 773197679Sdes sizeof(fd_mask)); 77476259Sgreen FD_SET(connection_in, setp); 775197679Sdes 776197679Sdes /* Wait for some data to arrive. */ 77776259Sgreen while (select(connection_in + 1, setp, NULL, NULL, NULL) == -1 && 778197679Sdes (errno == EAGAIN || errno == EINTR)) 779197679Sdes ; 780197679Sdes 781248619Sdes /* Read data from the socket. */ 78276259Sgreen len = read(connection_in, buf, sizeof(buf)); 78376259Sgreen if (len == 0) { 78492555Sdes log("Connection closed by %.200s", get_remote_ipaddr()); 785248619Sdes fatal_cleanup(); 78698675Sdes } 78798675Sdes if (len < 0) 788181111Sdes fatal("Read from socket failed: %.100s", strerror(errno)); 789181111Sdes /* Append it to the buffer. */ 790149749Sdes packet_process_incoming(buf, len); 791197679Sdes } 792197679Sdes /* NOTREACHED */ 79376259Sgreen} 79476259Sgreen 79576259Sgreenint 79676259Sgreenpacket_read(void) 79776259Sgreen{ 79876259Sgreen return packet_read_seqnr(NULL); 79976259Sgreen} 800124208Sdes 801124208Sdes/* 802124208Sdes * Waits until a packet has been received, verifies that its type matches 803124208Sdes * that given, and gives a fatal error and exits if there is a mismatch. 804124208Sdes */ 805124208Sdes 806124208Sdesvoid 807124208Sdespacket_read_expect(int expected_type) 808197679Sdes{ 809197679Sdes int type; 810197679Sdes 81176259Sgreen type = packet_read(); 81276259Sgreen if (type != expected_type) 81357429Smarkm packet_disconnect("Protocol error: expected packet type %d, got %d", 814149749Sdes expected_type, type); 815162852Sdes} 816149749Sdes 817149749Sdes/* Checks if a full packet is available in the data received so far via 818149749Sdes * packet_process_incoming. If so, reads the packet; otherwise returns 819149749Sdes * SSH_MSG_NONE. This does not wait for data from the connection. 820149749Sdes * 821149749Sdes * SSH_MSG_DISCONNECT is handled specially here. Also, 822149749Sdes * SSH_MSG_IGNORE messages are skipped by this function and are never returned 823149749Sdes * to higher levels. 824149749Sdes */ 825149749Sdes 826149749Sdesstatic int 827149749Sdespacket_read_poll1(void) 828197679Sdes{ 829149749Sdes u_int len, padded_len; 830162852Sdes u_char *cp, type; 831197679Sdes u_int checksum, stored_checksum; 832162852Sdes 833197679Sdes /* Check if input size is less than minimum packet size. */ 834149749Sdes if (buffer_len(&input) < 4 + 8) 835149749Sdes return SSH_MSG_NONE; 836149749Sdes /* Get length of incoming packet. */ 837149749Sdes cp = buffer_ptr(&input); 838149749Sdes len = GET_32BIT(cp); 839149749Sdes if (len < 1 + 2 + 2 || len > 256 * 1024) 840149749Sdes packet_disconnect("Bad packet length %d.", len); 841149749Sdes padded_len = (len + 8) & ~7; 842149749Sdes 843149749Sdes /* Check if the packet has been entirely received. */ 844149749Sdes if (buffer_len(&input) < 4 + padded_len) 845149749Sdes return SSH_MSG_NONE; 84660573Skris 84760573Skris /* The entire packet is in buffer. */ 84892555Sdes 849124208Sdes /* Consume packet length. */ 85060573Skris buffer_consume(&input, 4); 85192555Sdes 852248619Sdes /* 853248619Sdes * Cryptographic attack detector for ssh 854137015Sdes * (C)1998 CORE-SDI, Buenos Aires Argentina 85560573Skris * Ariel Futoransky(futo@core-sdi.com) 85660573Skris */ 85760573Skris if (!receive_context.plaintext && 85860573Skris detect_attack(buffer_ptr(&input), padded_len, NULL) == DEATTACK_DETECTED) 85960573Skris packet_disconnect("crc32 compensation attack: network attack detected"); 860197679Sdes 861197679Sdes /* Decrypt data to incoming_packet. */ 862197679Sdes buffer_clear(&incoming_packet); 863197679Sdes cp = buffer_append_space(&incoming_packet, padded_len); 864248619Sdes cipher_crypt(&receive_context, cp, buffer_ptr(&input), padded_len); 865248619Sdes 866248619Sdes buffer_consume(&input, padded_len); 86760573Skris 86892555Sdes#ifdef PACKET_DEBUG 869248619Sdes fprintf(stderr, "read_poll plain: "); 87060573Skris buffer_dump(&incoming_packet); 871197679Sdes#endif 87292555Sdes 87360573Skris /* Compute packet checksum. */ 87460573Skris checksum = ssh_crc32(buffer_ptr(&incoming_packet), 87560573Skris buffer_len(&incoming_packet) - 4); 876197679Sdes 87760573Skris /* Skip padding. */ 87860573Skris buffer_consume(&incoming_packet, 8 - len % 8); 87960573Skris 880197679Sdes /* Test check bytes. */ 88160573Skris if (len != buffer_len(&incoming_packet)) 882197679Sdes packet_disconnect("packet_read_poll1: len %d != buffer_len %d.", 883197679Sdes len, buffer_len(&incoming_packet)); 884197679Sdes 885197679Sdes cp = (u_char *)buffer_ptr(&incoming_packet) + len - 4; 886197679Sdes stored_checksum = GET_32BIT(cp); 887197679Sdes if (checksum != stored_checksum) 888197679Sdes packet_disconnect("Corrupted check bytes on input."); 889197679Sdes buffer_consume_end(&incoming_packet, 4); 890197679Sdes 89160573Skris if (packet_compression) { 892197679Sdes buffer_clear(&compression_buffer); 89360573Skris buffer_uncompress(&incoming_packet, &compression_buffer); 89460573Skris buffer_clear(&incoming_packet); 89560573Skris buffer_append(&incoming_packet, buffer_ptr(&compression_buffer), 896197679Sdes buffer_len(&compression_buffer)); 89760573Skris } 89860573Skris type = buffer_get_char(&incoming_packet); 89960573Skris return type; 90060573Skris} 90160573Skris 902248619Sdesstatic int 90360573Skrispacket_read_poll2(u_int32_t *seqnr_p) 90460573Skris{ 90560573Skris static u_int packet_length = 0; 906197679Sdes u_int padlen, need; 90792555Sdes u_char *macbuf, *cp, type; 908197679Sdes int maclen, block_size; 909197679Sdes Enc *enc = NULL; 910197679Sdes Mac *mac = NULL; 911197679Sdes Comp *comp = NULL; 91298675Sdes 913197679Sdes if (newkeys[MODE_IN] != NULL) { 91492555Sdes enc = &newkeys[MODE_IN]->enc; 915197679Sdes mac = &newkeys[MODE_IN]->mac; 91692555Sdes comp = &newkeys[MODE_IN]->comp; 917197679Sdes } 918197679Sdes maclen = mac && mac->enabled ? mac->mac_len : 0; 91960573Skris block_size = enc ? enc->block_size : 8; 92060573Skris 92160573Skris if (packet_length == 0) { 922137015Sdes /* 923137015Sdes * check if input size is less than the cipher block size, 924137015Sdes * decrypt first block and extract length of incoming packet 92560573Skris */ 92660573Skris if (buffer_len(&input) < block_size) 92760573Skris return SSH_MSG_NONE; 92860573Skris buffer_clear(&incoming_packet); 92960573Skris cp = buffer_append_space(&incoming_packet, block_size); 930248619Sdes cipher_crypt(&receive_context, cp, buffer_ptr(&input), 931248619Sdes block_size); 932248619Sdes cp = buffer_ptr(&incoming_packet); 93360573Skris packet_length = GET_32BIT(cp); 934248619Sdes if (packet_length < 1 + 4 || packet_length > 256 * 1024) { 93592555Sdes buffer_dump(&incoming_packet); 936248619Sdes packet_disconnect("Bad packet length %d.", packet_length); 937248619Sdes } 93860573Skris DBG(debug("input: packet len %d", packet_length+4)); 93960573Skris buffer_consume(&input, block_size); 940248619Sdes } 941197679Sdes /* we have a partial packet of block_size bytes */ 942248619Sdes need = 4 + packet_length - block_size; 943197679Sdes DBG(debug("partial packet %d, need %d, maclen %d", block_size, 94460573Skris need, maclen)); 94560573Skris if (need % block_size != 0) 946248619Sdes fatal("padding error: need %d block %d mod %d", 947197679Sdes need, block_size, need % block_size); 948197679Sdes /* 949248619Sdes * check if the entire packet has been received and 95060573Skris * decrypt into incoming_packet 951248619Sdes */ 952248619Sdes if (buffer_len(&input) < need + maclen) 953248619Sdes return SSH_MSG_NONE; 954248619Sdes#ifdef PACKET_DEBUG 955248619Sdes fprintf(stderr, "read_poll enc/full: "); 956248619Sdes buffer_dump(&input); 957248619Sdes#endif 958248619Sdes cp = buffer_append_space(&incoming_packet, need); 959197679Sdes cipher_crypt(&receive_context, cp, buffer_ptr(&input), need); 960248619Sdes buffer_consume(&input, need); 96160573Skris /* 96260573Skris * compute MAC over seqnr and packet, 963197679Sdes * increment sequence number for incoming packet 96460573Skris */ 96560573Skris if (mac && mac->enabled) { 966197679Sdes macbuf = mac_compute(mac, read_seqnr, 967124208Sdes buffer_ptr(&incoming_packet), 968197679Sdes buffer_len(&incoming_packet)); 969124208Sdes if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0) 970124208Sdes packet_disconnect("Corrupted MAC on input."); 971248619Sdes DBG(debug("MAC #%d ok", read_seqnr)); 972248619Sdes buffer_consume(&input, mac->mac_len); 973197679Sdes } 97460573Skris if (seqnr_p != NULL) 97576259Sgreen *seqnr_p = read_seqnr; 97676259Sgreen if (++read_seqnr == 0) 977197679Sdes log("incoming seqnr wraps around"); 978149749Sdes 97960573Skris /* get padlen */ 98060573Skris cp = buffer_ptr(&incoming_packet); 981124208Sdes padlen = cp[4]; 982124208Sdes DBG(debug("input: padlen %d", padlen)); 983124208Sdes if (padlen < 4) 984124208Sdes packet_disconnect("Corrupted padlen %d on input.", padlen); 985124208Sdes 986124208Sdes /* skip packet size + padlen, discard padding */ 987197679Sdes buffer_consume(&incoming_packet, 4 + 1); 988124208Sdes buffer_consume_end(&incoming_packet, padlen); 989124208Sdes 990124208Sdes DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet))); 991197679Sdes if (comp && comp->enabled) { 992240075Sdes buffer_clear(&compression_buffer); 993240075Sdes buffer_uncompress(&incoming_packet, &compression_buffer); 994240075Sdes buffer_clear(&incoming_packet); 995240075Sdes buffer_append(&incoming_packet, buffer_ptr(&compression_buffer), 996124208Sdes buffer_len(&compression_buffer)); 997124208Sdes DBG(debug("input: len after de-compress %d", buffer_len(&incoming_packet))); 998124208Sdes } 999197679Sdes /* 1000197679Sdes * get packet type, implies consume. 1001197679Sdes * return length of payload (without type field) 1002197679Sdes */ 1003124208Sdes type = buffer_get_char(&incoming_packet); 1004124208Sdes if (type == SSH2_MSG_NEWKEYS) 1005124208Sdes set_newkeys(MODE_IN); 1006124208Sdes#ifdef PACKET_DEBUG 1007124208Sdes fprintf(stderr, "read/plain[%d]:\r\n", type); 1008124208Sdes buffer_dump(&incoming_packet); 1009197679Sdes#endif 1010124208Sdes /* reset for next packet */ 1011124208Sdes packet_length = 0; 1012124208Sdes return type; 1013124208Sdes} 1014124208Sdes 1015197679Sdesint 1016197679Sdespacket_read_poll_seqnr(u_int32_t *seqnr_p) 1017124208Sdes{ 1018124208Sdes u_int reason, seqnr; 1019197679Sdes u_char type; 1020197679Sdes char *msg; 1021124208Sdes 1022197679Sdes for (;;) { 1023124208Sdes if (compat20) { 1024124208Sdes type = packet_read_poll2(seqnr_p); 1025124208Sdes if (type) 1026124208Sdes DBG(debug("received packet type %d", type)); 1027124208Sdes switch (type) { 1028124208Sdes case SSH2_MSG_IGNORE: 102960573Skris break; 103092555Sdes case SSH2_MSG_DEBUG: 103160573Skris packet_get_char(); 103292555Sdes msg = packet_get_string(NULL); 103360573Skris debug("Remote: %.900s", msg); 103460573Skris xfree(msg); 103560573Skris msg = packet_get_string(NULL); 103660573Skris xfree(msg); 103760573Skris break; 103860573Skris case SSH2_MSG_DISCONNECT: 103960573Skris reason = packet_get_int(); 104057429Smarkm msg = packet_get_string(NULL); 104157429Smarkm log("Received disconnect from %s: %u: %.400s", 104257429Smarkm get_remote_ipaddr(), reason, msg); 104357429Smarkm xfree(msg); 104457429Smarkm fatal_cleanup(); 104557429Smarkm break; 104692555Sdes case SSH2_MSG_UNIMPLEMENTED: 104757429Smarkm seqnr = packet_get_int(); 1048197679Sdes debug("Received SSH2_MSG_UNIMPLEMENTED for %u", 104976259Sgreen seqnr); 105057429Smarkm break; 1051181111Sdes default: 1052181111Sdes return type; 105360573Skris break; 105457429Smarkm } 1055197679Sdes } else { 1056197679Sdes type = packet_read_poll1(); 105776259Sgreen switch (type) { 105857429Smarkm case SSH_MSG_IGNORE: 105957429Smarkm break; 106057429Smarkm case SSH_MSG_DEBUG: 106157429Smarkm msg = packet_get_string(NULL); 106257429Smarkm debug("Remote: %.900s", msg); 106357429Smarkm xfree(msg); 106492555Sdes break; 106592555Sdes case SSH_MSG_DISCONNECT: 106660573Skris msg = packet_get_string(NULL); 106757429Smarkm log("Received disconnect from %s: %.400s", 106857429Smarkm get_remote_ipaddr(), msg); 106960573Skris fatal_cleanup(); 107092555Sdes xfree(msg); 107157429Smarkm break; 107276259Sgreen default: 107376259Sgreen if (type) 107457429Smarkm DBG(debug("received packet type %d", type)); 107576259Sgreen return type; 107657429Smarkm break; 107757429Smarkm } 107857429Smarkm } 107957429Smarkm } 1080197679Sdes} 1081197679Sdes 1082197679Sdesint 108357429Smarkmpacket_read_poll(void) 1084197679Sdes{ 1085197679Sdes return packet_read_poll_seqnr(NULL); 1086181111Sdes} 1087181111Sdes 108857429Smarkm/* 1089181111Sdes * Buffers the given amount of input characters. This is intended to be used 1090197679Sdes * together with packet_read_poll. 1091181111Sdes */ 1092181111Sdes 1093181111Sdesvoid 1094197679Sdespacket_process_incoming(const char *buf, u_int len) 1095197679Sdes{ 1096181111Sdes buffer_append(&input, buf, len); 1097197679Sdes} 1098181111Sdes 1099181111Sdes/* Returns a character from the packet. */ 1100197679Sdes 1101181111Sdesu_int 1102181111Sdespacket_get_char(void) 1103181111Sdes{ 1104181111Sdes char ch; 1105181111Sdes buffer_get(&incoming_packet, &ch, 1); 1106181111Sdes return (u_char) ch; 1107181111Sdes} 1108181111Sdes 1109181111Sdes/* Returns an integer from the packet data. */ 1110181111Sdes 1111181111Sdesu_int 1112181111Sdespacket_get_int(void) 111357429Smarkm{ 1114197679Sdes return buffer_get_int(&incoming_packet); 1115197679Sdes} 1116197679Sdes 1117197679Sdes/* 1118197679Sdes * Returns an arbitrary precision integer from the packet data. The integer 111957429Smarkm * must have been initialized before this call. 1120124208Sdes */ 1121126274Sdes 112257429Smarkmvoid 112357429Smarkmpacket_get_bignum(BIGNUM * value) 112457429Smarkm{ 112557429Smarkm buffer_get_bignum(&incoming_packet, value); 112657429Smarkm} 112757429Smarkm 112857429Smarkmvoid 112957429Smarkmpacket_get_bignum2(BIGNUM * value) 113057429Smarkm{ 113192555Sdes buffer_get_bignum2(&incoming_packet, value); 113292555Sdes} 113392555Sdes 113492555Sdesvoid * 113592555Sdespacket_get_raw(int *length_ptr) 113692555Sdes{ 113757429Smarkm int bytes = buffer_len(&incoming_packet); 113857429Smarkm if (length_ptr != NULL) 113957429Smarkm *length_ptr = bytes; 114057429Smarkm return buffer_ptr(&incoming_packet); 114157429Smarkm} 114257429Smarkm 114392555Sdesint 114457429Smarkmpacket_remaining(void) 114557429Smarkm{ 114657429Smarkm return buffer_len(&incoming_packet); 114792555Sdes} 114857429Smarkm 114957429Smarkm/* 115060573Skris * Returns a string from the packet data. The string is allocated using 115157429Smarkm * xmalloc; it is the responsibility of the calling program to free it when 115257429Smarkm * no longer needed. The length_ptr argument may be NULL, or point to an 115357429Smarkm * integer into which the length of the string is stored. 115457429Smarkm */ 115557429Smarkm 115657429Smarkmvoid * 115757429Smarkmpacket_get_string(u_int *length_ptr) 115857429Smarkm{ 115957429Smarkm return buffer_get_string(&incoming_packet, length_ptr); 116057429Smarkm} 116157429Smarkm 116292555Sdes/* 116392555Sdes * Sends a diagnostic message from the server to the client. This message 116457429Smarkm * can be sent at any time (but not while constructing another message). The 116576259Sgreen * message is printed immediately, but only if the client is being executed 116692555Sdes * in verbose mode. These messages are primarily intended to ease debugging 116776259Sgreen * authentication problems. The length of the formatted message must not 116857429Smarkm * exceed 1024 bytes. This will automatically call packet_write_wait. 116957429Smarkm */ 1170197679Sdes 117157429Smarkmvoid 117257429Smarkmpacket_send_debug(const char *fmt,...) 1173197679Sdes{ 1174162852Sdes char buf[1024]; 117557429Smarkm va_list args; 1176113908Sdes 117757429Smarkm if (compat20 && (datafellows & SSH_BUG_DEBUG)) 117857429Smarkm return; 117957429Smarkm 1180197679Sdes va_start(args, fmt); 118157429Smarkm vsnprintf(buf, sizeof(buf), fmt, args); 118257429Smarkm va_end(args); 118357429Smarkm 118457429Smarkm if (compat20) { 118557429Smarkm packet_start(SSH2_MSG_DEBUG); 1186197679Sdes packet_put_char(0); /* bool: always display */ 118757429Smarkm packet_put_cstring(buf); 118892555Sdes packet_put_cstring(""); 118992555Sdes } else { 119092555Sdes packet_start(SSH_MSG_DEBUG); 119192555Sdes packet_put_cstring(buf); 119292555Sdes } 1193197679Sdes packet_send(); 1194197679Sdes packet_write_wait(); 1195197679Sdes} 1196162852Sdes 1197162852Sdes/* 1198162852Sdes * Logs the error plus constructs and sends a disconnect packet, closes the 1199162852Sdes * connection, and exits. This function never returns. The error message 1200162852Sdes * should not contain a newline. The length of the formatted message must 1201162852Sdes * not exceed 1024 bytes. 1202162852Sdes */ 1203162852Sdes 120492555Sdesvoid 120592555Sdespacket_disconnect(const char *fmt,...) 1206197679Sdes{ 1207197679Sdes char buf[1024]; 1208197679Sdes va_list args; 1209248619Sdes static int disconnecting = 0; 121092555Sdes if (disconnecting) /* Guard against recursive invocations. */ 1211197679Sdes fatal("packet_disconnect called recursively."); 121257429Smarkm disconnecting = 1; 121357429Smarkm 121457429Smarkm /* 1215197679Sdes * Format the message. Note that the caller must make sure the 121657429Smarkm * message is of limited size. 121757429Smarkm */ 121857429Smarkm va_start(args, fmt); 1219197679Sdes vsnprintf(buf, sizeof(buf), fmt, args); 1220197679Sdes va_end(args); 122157429Smarkm 122257429Smarkm /* Send the disconnect message to the other side, and wait for it to get sent. */ 1223197679Sdes if (compat20) { 122457429Smarkm packet_start(SSH2_MSG_DISCONNECT); 122557429Smarkm packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR); 1226197679Sdes packet_put_cstring(buf); 122792555Sdes packet_put_cstring(""); 1228197679Sdes } else { 122957429Smarkm packet_start(SSH_MSG_DISCONNECT); 1230197679Sdes packet_put_cstring(buf); 1231162852Sdes } 123257429Smarkm packet_send(); 123357429Smarkm packet_write_wait(); 1234197679Sdes 123557429Smarkm /* Stop listening for connections. */ 1236197679Sdes channel_close_all(); 1237197679Sdes 1238197679Sdes /* Close the connection. */ 1239197679Sdes packet_close(); 1240197679Sdes 1241197679Sdes /* Display the error locally and exit. */ 1242197679Sdes log("Disconnecting: %.100s", buf); 1243197679Sdes fatal_cleanup(); 124457429Smarkm} 1245197679Sdes 1246197679Sdes/* Checks if there is any buffered output, and tries to write some of the output. */ 1247197679Sdes 1248146998Sdesvoid 1249146998Sdespacket_write_poll(void) 125092555Sdes{ 125160573Skris int len = buffer_len(&output); 125257429Smarkm if (len > 0) { 125392555Sdes len = write(connection_out, buffer_ptr(&output), len); 125492555Sdes if (len <= 0) { 125560573Skris if (errno == EAGAIN) 125676259Sgreen return; 1257248619Sdes else 1258248619Sdes fatal("Write failed: %.100s", strerror(errno)); 125960573Skris } 126060573Skris buffer_consume(&output, len); 126160573Skris } 126257429Smarkm} 1263197679Sdes 1264192595Sdes/* 1265192595Sdes * Calls packet_write_poll repeatedly until all pending output data has been 1266197679Sdes * written. 1267197679Sdes */ 1268197679Sdes 1269197679Sdesvoid 1270248619Sdespacket_write_wait(void) 1271248619Sdes{ 1272248619Sdes fd_set *setp; 127357429Smarkm 127460573Skris setp = (fd_set *)xmalloc(howmany(connection_out + 1, NFDBITS) * 127592555Sdes sizeof(fd_mask)); 1276248619Sdes packet_write_poll(); 127760573Skris while (packet_have_data_to_write()) { 1278248619Sdes memset(setp, 0, howmany(connection_out + 1, NFDBITS) * 1279248619Sdes sizeof(fd_mask)); 1280248619Sdes FD_SET(connection_out, setp); 1281248619Sdes while (select(connection_out + 1, NULL, setp, NULL, NULL) == -1 && 1282248619Sdes (errno == EAGAIN || errno == EINTR)) 1283248619Sdes ; 1284248619Sdes packet_write_poll(); 1285248619Sdes } 1286248619Sdes xfree(setp); 1287248619Sdes} 1288248619Sdes 1289248619Sdes/* Returns true if there is buffered data to write to the connection. */ 1290248619Sdes 1291248619Sdesint 1292248619Sdespacket_have_data_to_write(void) 129360573Skris{ 129460573Skris return buffer_len(&output) != 0; 129560573Skris} 129660573Skris 1297197679Sdes/* Returns true if there is not too much data to write to the connection. */ 129860573Skris 1299197679Sdesint 1300197679Sdespacket_not_very_much_data_to_write(void) 130160573Skris{ 1302197679Sdes if (interactive_mode) 1303248619Sdes return buffer_len(&output) < 16384; 1304197679Sdes else 1305240075Sdes return buffer_len(&output) < 128 * 1024; 1306197679Sdes} 1307197679Sdes 1308197679Sdes/* Informs that the current session is interactive. Sets IP flags for that. */ 1309124208Sdes 1310197679Sdesvoid 1311124208Sdespacket_set_interactive(int interactive) 1312197679Sdes{ 1313197679Sdes static int called = 0; 1314192595Sdes#if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) 1315192595Sdes int lowdelay = IPTOS_LOWDELAY; 131660573Skris int throughput = IPTOS_THROUGHPUT; 1317197679Sdes#endif 131860573Skris 1319248619Sdes if (called) 1320248619Sdes return; 1321248619Sdes called = 1; 1322248619Sdes 1323248619Sdes /* Record that we are in interactive mode. */ 1324248619Sdes interactive_mode = interactive; 1325248619Sdes 1326248619Sdes /* Only set socket options if using a socket. */ 1327248619Sdes if (!packet_connection_is_on_socket()) 1328248619Sdes return; 1329248619Sdes /* 1330248619Sdes * IPTOS_LOWDELAY and IPTOS_THROUGHPUT are IPv4 only 1331248619Sdes */ 1332192595Sdes if (interactive) { 1333192595Sdes /* 133460573Skris * Set IP options for an interactive connection. Use 1335197679Sdes * IPTOS_LOWDELAY and TCP_NODELAY. 1336192595Sdes */ 1337192595Sdes#if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) 1338192595Sdes if (packet_connection_is_ipv4()) { 133960573Skris if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, 134060573Skris &lowdelay, sizeof(lowdelay)) < 0) 1341248619Sdes error("setsockopt IPTOS_LOWDELAY: %.100s", 1342248619Sdes strerror(errno)); 1343248619Sdes } 1344248619Sdes#endif 1345248619Sdes set_nodelay(connection_in); 134660573Skris } else if (packet_connection_is_ipv4()) { 1347248619Sdes /* 134860573Skris * Set IP options for a non-interactive connection. Use 134960573Skris * IPTOS_THROUGHPUT. 135060573Skris */ 1351197679Sdes#if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) 135260573Skris if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, &throughput, 1353248619Sdes sizeof(throughput)) < 0) 1354248619Sdes error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno)); 1355248619Sdes#endif 1356248619Sdes } 1357248619Sdes} 1358197679Sdes 1359248619Sdes/* Returns true if the current connection is interactive. */ 1360248619Sdes 136160573Skrisint 136260573Skrispacket_is_interactive(void) 136360573Skris{ 136460573Skris return interactive_mode; 136560573Skris} 1366248619Sdes 1367248619Sdesint 1368248619Sdespacket_set_maxsize(int s) 1369248619Sdes{ 1370215116Sdes static int called = 0; 1371197679Sdes if (called) { 1372192595Sdes log("packet_set_maxsize: called twice: old %d new %d", 1373192595Sdes max_packet_size, s); 1374192595Sdes return -1; 1375197679Sdes } 1376192595Sdes if (s < 4 * 1024 || s > 1024 * 1024) { 1377192595Sdes log("packet_set_maxsize: bad size %d", s); 1378192595Sdes return -1; 1379192595Sdes } 1380197679Sdes called = 1; 1381197679Sdes debug("packet_set_maxsize: setting to %d", s); 138260573Skris max_packet_size = s; 1383192595Sdes return s; 138492555Sdes} 1385197679Sdes 1386197679Sdes/* roundup current message to pad bytes */ 1387124208Sdesvoid 1388197679Sdespacket_add_padding(u_char pad) 1389124208Sdes{ 1390124208Sdes extra_pad = pad; 1391197679Sdes} 1392197679Sdes 139360573Skris/* 139460573Skris * 9.2. Ignored Data Message 1395197679Sdes * 139692555Sdes * byte SSH_MSG_IGNORE 139760573Skris * string data 139860573Skris * 139960573Skris * All implementations MUST understand (and ignore) this message at any 140060573Skris * time (after receiving the protocol version). No implementation is 140160573Skris * required to send them. This message can be used as an additional 1402197679Sdes * protection measure against advanced traffic analysis techniques. 1403197679Sdes */ 140460573Skrisvoid 1405197679Sdespacket_send_ignore(int nbytes) 1406197679Sdes{ 140760573Skris u_int32_t rand = 0; 1408197679Sdes int i; 1409197679Sdes 1410197679Sdes packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE); 1411197679Sdes packet_put_int(nbytes); 1412197679Sdes for (i = 0; i < nbytes; i++) { 1413197679Sdes if (i % 4 == 0) 1414197679Sdes rand = arc4random(); 1415106121Sdes packet_put_char(rand & 0xff); 1416197679Sdes rand >>= 8; 141760573Skris } 141860573Skris} 141960573Skris