| /* $OpenBSD: packet.c,v 1.128 2006/03/25 13:17:02 djm Exp $ */ |
| /* |
| * Author: Tatu Ylonen <ylo@cs.hut.fi> |
| * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
| * All rights reserved |
| * This file contains code implementing the packet protocol and communication |
| * with the other side. This same code is used both on client and server side. |
| * |
| * As far as I am concerned, the code I have written for this software |
| * can be used freely for any purpose. Any derived versions of this |
| * software must be clearly marked as such, and if the derived work is |
| * incompatible with the protocol description in the RFC file, it must be |
| * called by a name other than "ssh" or "Secure Shell". |
| * |
| * |
| * SSH2 packet format added by Markus Friedl. |
| * Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #include "includes.h" |
| |
| #include "openbsd-compat/sys-queue.h" |
| #include <netinet/in_systm.h> |
| #include <netinet/ip.h> |
| |
| #include "xmalloc.h" |
| #include "buffer.h" |
| #include "packet.h" |
| #include "bufaux.h" |
| #include "crc32.h" |
| #include "getput.h" |
| |
| #include "compress.h" |
| #include "deattack.h" |
| #include "channels.h" |
| |
| #include "compat.h" |
| #include "ssh1.h" |
| #include "ssh2.h" |
| |
| #include "cipher.h" |
| #include "kex.h" |
| #include "mac.h" |
| #include "log.h" |
| #include "canohost.h" |
| #include "misc.h" |
| #include "ssh.h" |
| |
| #ifdef PACKET_DEBUG |
| #define DBG(x) x |
| #else |
| #define DBG(x) |
| #endif |
| |
| /* |
| * This variable contains the file descriptors used for communicating with |
| * the other side. connection_in is used for reading; connection_out for |
| * writing. These can be the same descriptor, in which case it is assumed to |
| * be a socket. |
| */ |
| static int connection_in = -1; |
| static int connection_out = -1; |
| |
| /* Protocol flags for the remote side. */ |
| static u_int remote_protocol_flags = 0; |
| |
| /* Encryption context for receiving data. This is only used for decryption. */ |
| static CipherContext receive_context; |
| |
| /* Encryption context for sending data. This is only used for encryption. */ |
| static CipherContext send_context; |
| |
| /* Buffer for raw input data from the socket. */ |
| Buffer input; |
| |
| /* Buffer for raw output data going to the socket. */ |
| Buffer output; |
| |
| /* Buffer for the partial outgoing packet being constructed. */ |
| static Buffer outgoing_packet; |
| |
| /* Buffer for the incoming packet currently being processed. */ |
| static Buffer incoming_packet; |
| |
| /* Scratch buffer for packet compression/decompression. */ |
| static Buffer compression_buffer; |
| static int compression_buffer_ready = 0; |
| |
| /* Flag indicating whether packet compression/decompression is enabled. */ |
| static int packet_compression = 0; |
| |
| /* default maximum packet size */ |
| u_int max_packet_size = 32768; |
| |
| /* Flag indicating whether this module has been initialized. */ |
| static int initialized = 0; |
| |
| /* Set to true if the connection is interactive. */ |
| static int interactive_mode = 0; |
| |
| /* Set to true if we are the server side. */ |
| static int server_side = 0; |
| |
| /* Set to true if we are authenticated. */ |
| static int after_authentication = 0; |
| |
| /* Session key information for Encryption and MAC */ |
| Newkeys *newkeys[MODE_MAX]; |
| static struct packet_state { |
| u_int32_t seqnr; |
| u_int32_t packets; |
| u_int64_t blocks; |
| } p_read, p_send; |
| |
| static u_int64_t max_blocks_in, max_blocks_out; |
| static u_int32_t rekey_limit; |
| |
| /* Session key for protocol v1 */ |
| static u_char ssh1_key[SSH_SESSION_KEY_LENGTH]; |
| static u_int ssh1_keylen; |
| |
| /* roundup current message to extra_pad bytes */ |
| static u_char extra_pad = 0; |
| |
| struct packet { |
| TAILQ_ENTRY(packet) next; |
| u_char type; |
| Buffer payload; |
| }; |
| TAILQ_HEAD(, packet) outgoing; |
| |
| /* |
| * Sets the descriptors used for communication. Disables encryption until |
| * packet_set_encryption_key is called. |
| */ |
| void |
| packet_set_connection(int fd_in, int fd_out) |
| { |
| Cipher *none = cipher_by_name("none"); |
| |
| if (none == NULL) |
| fatal("packet_set_connection: cannot load cipher 'none'"); |
| connection_in = fd_in; |
| connection_out = fd_out; |
| cipher_init(&send_context, none, (const u_char *)"", |
| 0, NULL, 0, CIPHER_ENCRYPT); |
| cipher_init(&receive_context, none, (const u_char *)"", |
| 0, NULL, 0, CIPHER_DECRYPT); |
| newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL; |
| if (!initialized) { |
| initialized = 1; |
| buffer_init(&input); |
| buffer_init(&output); |
| buffer_init(&outgoing_packet); |
| buffer_init(&incoming_packet); |
| TAILQ_INIT(&outgoing); |
| } |
| } |
| |
| /* Returns 1 if remote host is connected via socket, 0 if not. */ |
| |
| int |
| packet_connection_is_on_socket(void) |
| { |
| struct sockaddr_storage from, to; |
| socklen_t fromlen, tolen; |
| |
| /* filedescriptors in and out are the same, so it's a socket */ |
| if (connection_in == connection_out) |
| return 1; |
| fromlen = sizeof(from); |
| memset(&from, 0, sizeof(from)); |
| if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0) |
| return 0; |
| tolen = sizeof(to); |
| memset(&to, 0, sizeof(to)); |
| if (getpeername(connection_out, (struct sockaddr *)&to, &tolen) < 0) |
| return 0; |
| if (fromlen != tolen || memcmp(&from, &to, fromlen) != 0) |
| return 0; |
| if (from.ss_family != AF_INET && from.ss_family != AF_INET6) |
| return 0; |
| return 1; |
| } |
| |
| /* |
| * Exports an IV from the CipherContext required to export the key |
| * state back from the unprivileged child to the privileged parent |
| * process. |
| */ |
| |
| void |
| packet_get_keyiv(int mode, u_char *iv, u_int len) |
| { |
| CipherContext *cc; |
| |
| if (mode == MODE_OUT) |
| cc = &send_context; |
| else |
| cc = &receive_context; |
| |
| cipher_get_keyiv(cc, iv, len); |
| } |
| |
| int |
| packet_get_keycontext(int mode, u_char *dat) |
| { |
| CipherContext *cc; |
| |
| if (mode == MODE_OUT) |
| cc = &send_context; |
| else |
| cc = &receive_context; |
| |
| return (cipher_get_keycontext(cc, dat)); |
| } |
| |
| void |
| packet_set_keycontext(int mode, u_char *dat) |
| { |
| CipherContext *cc; |
| |
| if (mode == MODE_OUT) |
| cc = &send_context; |
| else |
| cc = &receive_context; |
| |
| cipher_set_keycontext(cc, dat); |
| } |
| |
| int |
| packet_get_keyiv_len(int mode) |
| { |
| CipherContext *cc; |
| |
| if (mode == MODE_OUT) |
| cc = &send_context; |
| else |
| cc = &receive_context; |
| |
| return (cipher_get_keyiv_len(cc)); |
| } |
| |
| void |
| packet_set_iv(int mode, u_char *dat) |
| { |
| CipherContext *cc; |
| |
| if (mode == MODE_OUT) |
| cc = &send_context; |
| else |
| cc = &receive_context; |
| |
| cipher_set_keyiv(cc, dat); |
| } |
| |
| int |
| packet_get_ssh1_cipher(void) |
| { |
| return (cipher_get_number(receive_context.cipher)); |
| } |
| |
| void |
| packet_get_state(int mode, u_int32_t *seqnr, u_int64_t *blocks, u_int32_t *packets) |
| { |
| struct packet_state *state; |
| |
| state = (mode == MODE_IN) ? &p_read : &p_send; |
| *seqnr = state->seqnr; |
| *blocks = state->blocks; |
| *packets = state->packets; |
| } |
| |
| void |
| packet_set_state(int mode, u_int32_t seqnr, u_int64_t blocks, u_int32_t packets) |
| { |
| struct packet_state *state; |
| |
| state = (mode == MODE_IN) ? &p_read : &p_send; |
| state->seqnr = seqnr; |
| state->blocks = blocks; |
| state->packets = packets; |
| } |
| |
| /* returns 1 if connection is via ipv4 */ |
| |
| int |
| packet_connection_is_ipv4(void) |
| { |
| struct sockaddr_storage to; |
| socklen_t tolen = sizeof(to); |
| |
| memset(&to, 0, sizeof(to)); |
| if (getsockname(connection_out, (struct sockaddr *)&to, &tolen) < 0) |
| return 0; |
| if (to.ss_family == AF_INET) |
| return 1; |
| #ifdef IPV4_IN_IPV6 |
| if (to.ss_family == AF_INET6 && |
| IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&to)->sin6_addr)) |
| return 1; |
| #endif |
| return 0; |
| } |
| |
| /* Sets the connection into non-blocking mode. */ |
| |
| void |
| packet_set_nonblocking(void) |
| { |
| /* Set the socket into non-blocking mode. */ |
| set_nonblock(connection_in); |
| |
| if (connection_out != connection_in) |
| set_nonblock(connection_out); |
| } |
| |
| /* Returns the socket used for reading. */ |
| |
| int |
| packet_get_connection_in(void) |
| { |
| return connection_in; |
| } |
| |
| /* Returns the descriptor used for writing. */ |
| |
| int |
| packet_get_connection_out(void) |
| { |
| return connection_out; |
| } |
| |
| /* Closes the connection and clears and frees internal data structures. */ |
| |
| void |
| packet_close(void) |
| { |
| if (!initialized) |
| return; |
| initialized = 0; |
| if (connection_in == connection_out) { |
| shutdown(connection_out, SHUT_RDWR); |
| close(connection_out); |
| } else { |
| close(connection_in); |
| close(connection_out); |
| } |
| buffer_free(&input); |
| buffer_free(&output); |
| buffer_free(&outgoing_packet); |
| buffer_free(&incoming_packet); |
| if (compression_buffer_ready) { |
| buffer_free(&compression_buffer); |
| buffer_compress_uninit(); |
| } |
| cipher_cleanup(&send_context); |
| cipher_cleanup(&receive_context); |
| } |
| |
| /* Sets remote side protocol flags. */ |
| |
| void |
| packet_set_protocol_flags(u_int protocol_flags) |
| { |
| remote_protocol_flags = protocol_flags; |
| } |
| |
| /* Returns the remote protocol flags set earlier by the above function. */ |
| |
| u_int |
| packet_get_protocol_flags(void) |
| { |
| return remote_protocol_flags; |
| } |
| |
| /* |
| * Starts packet compression from the next packet on in both directions. |
| * Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. |
| */ |
| |
| static void |
| packet_init_compression(void) |
| { |
| if (compression_buffer_ready == 1) |
| return; |
| compression_buffer_ready = 1; |
| buffer_init(&compression_buffer); |
| } |
| |
| void |
| packet_start_compression(int level) |
| { |
| if (packet_compression && !compat20) |
| fatal("Compression already enabled."); |
| packet_compression = 1; |
| packet_init_compression(); |
| buffer_compress_init_send(level); |
| buffer_compress_init_recv(); |
| } |
| |
| /* |
| * Causes any further packets to be encrypted using the given key. The same |
| * key is used for both sending and reception. However, both directions are |
| * encrypted independently of each other. |
| */ |
| |
| void |
| packet_set_encryption_key(const u_char *key, u_int keylen, |
| int number) |
| { |
| Cipher *cipher = cipher_by_number(number); |
| |
| if (cipher == NULL) |
| fatal("packet_set_encryption_key: unknown cipher number %d", number); |
| if (keylen < 20) |
| fatal("packet_set_encryption_key: keylen too small: %d", keylen); |
| if (keylen > SSH_SESSION_KEY_LENGTH) |
| fatal("packet_set_encryption_key: keylen too big: %d", keylen); |
| memcpy(ssh1_key, key, keylen); |
| ssh1_keylen = keylen; |
| cipher_init(&send_context, cipher, key, keylen, NULL, 0, CIPHER_ENCRYPT); |
| cipher_init(&receive_context, cipher, key, keylen, NULL, 0, CIPHER_DECRYPT); |
| } |
| |
| u_int |
| packet_get_encryption_key(u_char *key) |
| { |
| if (key == NULL) |
| return (ssh1_keylen); |
| memcpy(key, ssh1_key, ssh1_keylen); |
| return (ssh1_keylen); |
| } |
| |
| /* Start constructing a packet to send. */ |
| void |
| packet_start(u_char type) |
| { |
| u_char buf[9]; |
| int len; |
| |
| DBG(debug("packet_start[%d]", type)); |
| len = compat20 ? 6 : 9; |
| memset(buf, 0, len - 1); |
| buf[len - 1] = type; |
| buffer_clear(&outgoing_packet); |
| buffer_append(&outgoing_packet, buf, len); |
| } |
| |
| /* Append payload. */ |
| void |
| packet_put_char(int value) |
| { |
| char ch = value; |
| |
| buffer_append(&outgoing_packet, &ch, 1); |
| } |
| |
| void |
| packet_put_int(u_int value) |
| { |
| buffer_put_int(&outgoing_packet, value); |
| } |
| |
| void |
| packet_put_string(const void *buf, u_int len) |
| { |
| buffer_put_string(&outgoing_packet, buf, len); |
| } |
| |
| void |
| packet_put_cstring(const char *str) |
| { |
| buffer_put_cstring(&outgoing_packet, str); |
| } |
| |
| void |
| packet_put_raw(const void *buf, u_int len) |
| { |
| buffer_append(&outgoing_packet, buf, len); |
| } |
| |
| void |
| packet_put_bignum(BIGNUM * value) |
| { |
| buffer_put_bignum(&outgoing_packet, value); |
| } |
| |
| void |
| packet_put_bignum2(BIGNUM * value) |
| { |
| buffer_put_bignum2(&outgoing_packet, value); |
| } |
| |
| /* |
| * Finalizes and sends the packet. If the encryption key has been set, |
| * encrypts the packet before sending. |
| */ |
| |
| static void |
| packet_send1(void) |
| { |
| u_char buf[8], *cp; |
| int i, padding, len; |
| u_int checksum; |
| u_int32_t rnd = 0; |
| |
| /* |
| * If using packet compression, compress the payload of the outgoing |
| * packet. |
| */ |
| if (packet_compression) { |
| buffer_clear(&compression_buffer); |
| /* Skip padding. */ |
| buffer_consume(&outgoing_packet, 8); |
| /* padding */ |
| buffer_append(&compression_buffer, "\0\0\0\0\0\0\0\0", 8); |
| buffer_compress(&outgoing_packet, &compression_buffer); |
| buffer_clear(&outgoing_packet); |
| buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer), |
| buffer_len(&compression_buffer)); |
| } |
| /* Compute packet length without padding (add checksum, remove padding). */ |
| len = buffer_len(&outgoing_packet) + 4 - 8; |
| |
| /* Insert padding. Initialized to zero in packet_start1() */ |
| padding = 8 - len % 8; |
| if (!send_context.plaintext) { |
| cp = buffer_ptr(&outgoing_packet); |
| for (i = 0; i < padding; i++) { |
| if (i % 4 == 0) |
| rnd = arc4random(); |
| cp[7 - i] = rnd & 0xff; |
| rnd >>= 8; |
| } |
| } |
| buffer_consume(&outgoing_packet, 8 - padding); |
| |
| /* Add check bytes. */ |
| checksum = ssh_crc32(buffer_ptr(&outgoing_packet), |
| buffer_len(&outgoing_packet)); |
| PUT_32BIT(buf, checksum); |
| buffer_append(&outgoing_packet, buf, 4); |
| |
| #ifdef PACKET_DEBUG |
| fprintf(stderr, "packet_send plain: "); |
| buffer_dump(&outgoing_packet); |
| #endif |
| |
| /* Append to output. */ |
| PUT_32BIT(buf, len); |
| buffer_append(&output, buf, 4); |
| cp = buffer_append_space(&output, buffer_len(&outgoing_packet)); |
| cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet), |
| buffer_len(&outgoing_packet)); |
| |
| #ifdef PACKET_DEBUG |
| fprintf(stderr, "encrypted: "); |
| buffer_dump(&output); |
| #endif |
| |
| buffer_clear(&outgoing_packet); |
| |
| /* |
| * Note that the packet is now only buffered in output. It won't be |
| * actually sent until packet_write_wait or packet_write_poll is |
| * called. |
| */ |
| } |
| |
| void |
| set_newkeys(int mode) |
| { |
| Enc *enc; |
| Mac *mac; |
| Comp *comp; |
| CipherContext *cc; |
| u_int64_t *max_blocks; |
| int crypt_type; |
| |
| debug2("set_newkeys: mode %d", mode); |
| |
| if (mode == MODE_OUT) { |
| cc = &send_context; |
| crypt_type = CIPHER_ENCRYPT; |
| p_send.packets = p_send.blocks = 0; |
| max_blocks = &max_blocks_out; |
| } else { |
| cc = &receive_context; |
| crypt_type = CIPHER_DECRYPT; |
| p_read.packets = p_read.blocks = 0; |
| max_blocks = &max_blocks_in; |
| } |
| if (newkeys[mode] != NULL) { |
| debug("set_newkeys: rekeying"); |
| cipher_cleanup(cc); |
| enc = &newkeys[mode]->enc; |
| mac = &newkeys[mode]->mac; |
| comp = &newkeys[mode]->comp; |
| memset(mac->key, 0, mac->key_len); |
| xfree(enc->name); |
| xfree(enc->iv); |
| xfree(enc->key); |
| xfree(mac->name); |
| xfree(mac->key); |
| xfree(comp->name); |
| xfree(newkeys[mode]); |
| } |
| newkeys[mode] = kex_get_newkeys(mode); |
| if (newkeys[mode] == NULL) |
| fatal("newkeys: no keys for mode %d", mode); |
| enc = &newkeys[mode]->enc; |
| mac = &newkeys[mode]->mac; |
| comp = &newkeys[mode]->comp; |
| if (mac->md != NULL) |
| mac->enabled = 1; |
| DBG(debug("cipher_init_context: %d", mode)); |
| cipher_init(cc, enc->cipher, enc->key, enc->key_len, |
| enc->iv, enc->block_size, crypt_type); |
| /* Deleting the keys does not gain extra security */ |
| /* memset(enc->iv, 0, enc->block_size); |
| memset(enc->key, 0, enc->key_len); */ |
| if ((comp->type == COMP_ZLIB || |
| (comp->type == COMP_DELAYED && after_authentication)) && |
| comp->enabled == 0) { |
| packet_init_compression(); |
| if (mode == MODE_OUT) |
| buffer_compress_init_send(6); |
| else |
| buffer_compress_init_recv(); |
| comp->enabled = 1; |
| } |
| /* |
| * The 2^(blocksize*2) limit is too expensive for 3DES, |
| * blowfish, etc, so enforce a 1GB limit for small blocksizes. |
| */ |
| if (enc->block_size >= 16) |
| *max_blocks = (u_int64_t)1 << (enc->block_size*2); |
| else |
| *max_blocks = ((u_int64_t)1 << 30) / enc->block_size; |
| if (rekey_limit) |
| *max_blocks = MIN(*max_blocks, rekey_limit / enc->block_size); |
| } |
| |
| /* |
| * Delayed compression for SSH2 is enabled after authentication: |
| * This happans on the server side after a SSH2_MSG_USERAUTH_SUCCESS is sent, |
| * and on the client side after a SSH2_MSG_USERAUTH_SUCCESS is received. |
| */ |
| static void |
| packet_enable_delayed_compress(void) |
| { |
| Comp *comp = NULL; |
| int mode; |
| |
| /* |
| * Remember that we are past the authentication step, so rekeying |
| * with COMP_DELAYED will turn on compression immediately. |
| */ |
| after_authentication = 1; |
| for (mode = 0; mode < MODE_MAX; mode++) { |
| comp = &newkeys[mode]->comp; |
| if (comp && !comp->enabled && comp->type == COMP_DELAYED) { |
| packet_init_compression(); |
| if (mode == MODE_OUT) |
| buffer_compress_init_send(6); |
| else |
| buffer_compress_init_recv(); |
| comp->enabled = 1; |
| } |
| } |
| } |
| |
| /* |
| * Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) |
| */ |
| static void |
| packet_send2_wrapped(void) |
| { |
| u_char type, *cp, *macbuf = NULL; |
| u_char padlen, pad; |
| u_int packet_length = 0; |
| u_int i, len; |
| u_int32_t rnd = 0; |
| Enc *enc = NULL; |
| Mac *mac = NULL; |
| Comp *comp = NULL; |
| int block_size; |
| |
| if (newkeys[MODE_OUT] != NULL) { |
| enc = &newkeys[MODE_OUT]->enc; |
| mac = &newkeys[MODE_OUT]->mac; |
| comp = &newkeys[MODE_OUT]->comp; |
| } |
| block_size = enc ? enc->block_size : 8; |
| |
| cp = buffer_ptr(&outgoing_packet); |
| type = cp[5]; |
| |
| #ifdef PACKET_DEBUG |
| fprintf(stderr, "plain: "); |
| buffer_dump(&outgoing_packet); |
| #endif |
| |
| if (comp && comp->enabled) { |
| len = buffer_len(&outgoing_packet); |
| /* skip header, compress only payload */ |
| buffer_consume(&outgoing_packet, 5); |
| buffer_clear(&compression_buffer); |
| buffer_compress(&outgoing_packet, &compression_buffer); |
| buffer_clear(&outgoing_packet); |
| buffer_append(&outgoing_packet, "\0\0\0\0\0", 5); |
| buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer), |
| buffer_len(&compression_buffer)); |
| DBG(debug("compression: raw %d compressed %d", len, |
| buffer_len(&outgoing_packet))); |
| } |
| |
| /* sizeof (packet_len + pad_len + payload) */ |
| len = buffer_len(&outgoing_packet); |
| |
| /* |
| * calc size of padding, alloc space, get random data, |
| * minimum padding is 4 bytes |
| */ |
| padlen = block_size - (len % block_size); |
| if (padlen < 4) |
| padlen += block_size; |
| if (extra_pad) { |
| /* will wrap if extra_pad+padlen > 255 */ |
| extra_pad = roundup(extra_pad, block_size); |
| pad = extra_pad - ((len + padlen) % extra_pad); |
| debug3("packet_send2: adding %d (len %d padlen %d extra_pad %d)", |
| pad, len, padlen, extra_pad); |
| padlen += pad; |
| extra_pad = 0; |
| } |
| cp = buffer_append_space(&outgoing_packet, padlen); |
| if (enc && !send_context.plaintext) { |
| /* random padding */ |
| for (i = 0; i < padlen; i++) { |
| if (i % 4 == 0) |
| rnd = arc4random(); |
| cp[i] = rnd & 0xff; |
| rnd >>= 8; |
| } |
| } else { |
| /* clear padding */ |
| memset(cp, 0, padlen); |
| } |
| /* packet_length includes payload, padding and padding length field */ |
| packet_length = buffer_len(&outgoing_packet) - 4; |
| cp = buffer_ptr(&outgoing_packet); |
| PUT_32BIT(cp, packet_length); |
| cp[4] = padlen; |
| DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen)); |
| |
| /* compute MAC over seqnr and packet(length fields, payload, padding) */ |
| if (mac && mac->enabled) { |
| macbuf = mac_compute(mac, p_send.seqnr, |
| buffer_ptr(&outgoing_packet), |
| buffer_len(&outgoing_packet)); |
| DBG(debug("done calc MAC out #%d", p_send.seqnr)); |
| } |
| /* encrypt packet and append to output buffer. */ |
| cp = buffer_append_space(&output, buffer_len(&outgoing_packet)); |
| cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet), |
| buffer_len(&outgoing_packet)); |
| /* append unencrypted MAC */ |
| if (mac && mac->enabled) |
| buffer_append(&output, (char *)macbuf, mac->mac_len); |
| #ifdef PACKET_DEBUG |
| fprintf(stderr, "encrypted: "); |
| buffer_dump(&output); |
| #endif |
| /* increment sequence number for outgoing packets */ |
| if (++p_send.seqnr == 0) |
| logit("outgoing seqnr wraps around"); |
| if (++p_send.packets == 0) |
| if (!(datafellows & SSH_BUG_NOREKEY)) |
| fatal("XXX too many packets with same key"); |
| p_send.blocks += (packet_length + 4) / block_size; |
| buffer_clear(&outgoing_packet); |
| |
| if (type == SSH2_MSG_NEWKEYS) |
| set_newkeys(MODE_OUT); |
| else if (type == SSH2_MSG_USERAUTH_SUCCESS && server_side) |
| packet_enable_delayed_compress(); |
| } |
| |
| static void |
| packet_send2(void) |
| { |
| static int rekeying = 0; |
| struct packet *p; |
| u_char type, *cp; |
| |
| cp = buffer_ptr(&outgoing_packet); |
| type = cp[5]; |
| |
| /* during rekeying we can only send key exchange messages */ |
| if (rekeying) { |
| if (!((type >= SSH2_MSG_TRANSPORT_MIN) && |
| (type <= SSH2_MSG_TRANSPORT_MAX))) { |
| debug("enqueue packet: %u", type); |
| p = xmalloc(sizeof(*p)); |
| p->type = type; |
| memcpy(&p->payload, &outgoing_packet, sizeof(Buffer)); |
| buffer_init(&outgoing_packet); |
| TAILQ_INSERT_TAIL(&outgoing, p, next); |
| return; |
| } |
| } |
| |
| /* rekeying starts with sending KEXINIT */ |
| if (type == SSH2_MSG_KEXINIT) |
| rekeying = 1; |
| |
| packet_send2_wrapped(); |
| |
| /* after a NEWKEYS message we can send the complete queue */ |
| if (type == SSH2_MSG_NEWKEYS) { |
| rekeying = 0; |
| while ((p = TAILQ_FIRST(&outgoing))) { |
| type = p->type; |
| debug("dequeue packet: %u", type); |
| buffer_free(&outgoing_packet); |
| memcpy(&outgoing_packet, &p->payload, |
| sizeof(Buffer)); |
| TAILQ_REMOVE(&outgoing, p, next); |
| xfree(p); |
| packet_send2_wrapped(); |
| } |
| } |
| } |
| |
| void |
| packet_send(void) |
| { |
| if (compat20) |
| packet_send2(); |
| else |
| packet_send1(); |
| DBG(debug("packet_send done")); |
| } |
| |
| /* |
| * Waits until a packet has been received, and returns its type. Note that |
| * no other data is processed until this returns, so this function should not |
| * be used during the interactive session. |
| */ |
| |
| int |
| packet_read_seqnr(u_int32_t *seqnr_p) |
| { |
| int type, len; |
| fd_set *setp; |
| char buf[8192]; |
| DBG(debug("packet_read()")); |
| |
| setp = (fd_set *)xcalloc(howmany(connection_in+1, NFDBITS), |
| sizeof(fd_mask)); |
| |
| /* Since we are blocking, ensure that all written packets have been sent. */ |
| packet_write_wait(); |
| |
| /* Stay in the loop until we have received a complete packet. */ |
| for (;;) { |
| /* Try to read a packet from the buffer. */ |
| type = packet_read_poll_seqnr(seqnr_p); |
| if (!compat20 && ( |
| type == SSH_SMSG_SUCCESS |
| || type == SSH_SMSG_FAILURE |
| || type == SSH_CMSG_EOF |
| || type == SSH_CMSG_EXIT_CONFIRMATION)) |
| packet_check_eom(); |
| /* If we got a packet, return it. */ |
| if (type != SSH_MSG_NONE) { |
| xfree(setp); |
| return type; |
| } |
| /* |
| * Otherwise, wait for some data to arrive, add it to the |
| * buffer, and try again. |
| */ |
| memset(setp, 0, howmany(connection_in + 1, NFDBITS) * |
| sizeof(fd_mask)); |
| FD_SET(connection_in, setp); |
| |
| /* Wait for some data to arrive. */ |
| while (select(connection_in + 1, setp, NULL, NULL, NULL) == -1 && |
| (errno == EAGAIN || errno == EINTR)) |
| ; |
| |
| /* Read data from the socket. */ |
| len = read(connection_in, buf, sizeof(buf)); |
| if (len == 0) { |
| logit("Connection closed by %.200s", get_remote_ipaddr()); |
| cleanup_exit(255); |
| } |
| if (len < 0) |
| fatal("Read from socket failed: %.100s", strerror(errno)); |
| /* Append it to the buffer. */ |
| packet_process_incoming(buf, len); |
| } |
| /* NOTREACHED */ |
| } |
| |
| int |
| packet_read(void) |
| { |
| return packet_read_seqnr(NULL); |
| } |
| |
| /* |
| * Waits until a packet has been received, verifies that its type matches |
| * that given, and gives a fatal error and exits if there is a mismatch. |
| */ |
| |
| void |
| packet_read_expect(int expected_type) |
| { |
| int type; |
| |
| type = packet_read(); |
| if (type != expected_type) |
| packet_disconnect("Protocol error: expected packet type %d, got %d", |
| expected_type, type); |
| } |
| |
| /* Checks if a full packet is available in the data received so far via |
| * packet_process_incoming. If so, reads the packet; otherwise returns |
| * SSH_MSG_NONE. This does not wait for data from the connection. |
| * |
| * SSH_MSG_DISCONNECT is handled specially here. Also, |
| * SSH_MSG_IGNORE messages are skipped by this function and are never returned |
| * to higher levels. |
| */ |
| |
| static int |
| packet_read_poll1(void) |
| { |
| u_int len, padded_len; |
| u_char *cp, type; |
| u_int checksum, stored_checksum; |
| |
| /* Check if input size is less than minimum packet size. */ |
| if (buffer_len(&input) < 4 + 8) |
| return SSH_MSG_NONE; |
| /* Get length of incoming packet. */ |
| cp = buffer_ptr(&input); |
| len = GET_32BIT(cp); |
| if (len < 1 + 2 + 2 || len > 256 * 1024) |
| packet_disconnect("Bad packet length %u.", len); |
| padded_len = (len + 8) & ~7; |
| |
| /* Check if the packet has been entirely received. */ |
| if (buffer_len(&input) < 4 + padded_len) |
| return SSH_MSG_NONE; |
| |
| /* The entire packet is in buffer. */ |
| |
| /* Consume packet length. */ |
| buffer_consume(&input, 4); |
| |
| /* |
| * Cryptographic attack detector for ssh |
| * (C)1998 CORE-SDI, Buenos Aires Argentina |
| * Ariel Futoransky(futo@core-sdi.com) |
| */ |
| if (!receive_context.plaintext && |
| detect_attack(buffer_ptr(&input), padded_len) == DEATTACK_DETECTED) |
| packet_disconnect("crc32 compensation attack: network attack detected"); |
| |
| /* Decrypt data to incoming_packet. */ |
| buffer_clear(&incoming_packet); |
| cp = buffer_append_space(&incoming_packet, padded_len); |
| cipher_crypt(&receive_context, cp, buffer_ptr(&input), padded_len); |
| |
| buffer_consume(&input, padded_len); |
| |
| #ifdef PACKET_DEBUG |
| fprintf(stderr, "read_poll plain: "); |
| buffer_dump(&incoming_packet); |
| #endif |
| |
| /* Compute packet checksum. */ |
| checksum = ssh_crc32(buffer_ptr(&incoming_packet), |
| buffer_len(&incoming_packet) - 4); |
| |
| /* Skip padding. */ |
| buffer_consume(&incoming_packet, 8 - len % 8); |
| |
| /* Test check bytes. */ |
| if (len != buffer_len(&incoming_packet)) |
| packet_disconnect("packet_read_poll1: len %d != buffer_len %d.", |
| len, buffer_len(&incoming_packet)); |
| |
| cp = (u_char *)buffer_ptr(&incoming_packet) + len - 4; |
| stored_checksum = GET_32BIT(cp); |
| if (checksum != stored_checksum) |
| packet_disconnect("Corrupted check bytes on input."); |
| buffer_consume_end(&incoming_packet, 4); |
| |
| if (packet_compression) { |
| buffer_clear(&compression_buffer); |
| buffer_uncompress(&incoming_packet, &compression_buffer); |
| buffer_clear(&incoming_packet); |
| buffer_append(&incoming_packet, buffer_ptr(&compression_buffer), |
| buffer_len(&compression_buffer)); |
| } |
| type = buffer_get_char(&incoming_packet); |
| if (type < SSH_MSG_MIN || type > SSH_MSG_MAX) |
| packet_disconnect("Invalid ssh1 packet type: %d", type); |
| return type; |
| } |
| |
| static int |
| packet_read_poll2(u_int32_t *seqnr_p) |
| { |
| static u_int packet_length = 0; |
| u_int padlen, need; |
| u_char *macbuf, *cp, type; |
| u_int maclen, block_size; |
| Enc *enc = NULL; |
| Mac *mac = NULL; |
| Comp *comp = NULL; |
| |
| if (newkeys[MODE_IN] != NULL) { |
| enc = &newkeys[MODE_IN]->enc; |
| mac = &newkeys[MODE_IN]->mac; |
| comp = &newkeys[MODE_IN]->comp; |
| } |
| maclen = mac && mac->enabled ? mac->mac_len : 0; |
| block_size = enc ? enc->block_size : 8; |
| |
| if (packet_length == 0) { |
| /* |
| * check if input size is less than the cipher block size, |
| * decrypt first block and extract length of incoming packet |
| */ |
| if (buffer_len(&input) < block_size) |
| return SSH_MSG_NONE; |
| buffer_clear(&incoming_packet); |
| cp = buffer_append_space(&incoming_packet, block_size); |
| cipher_crypt(&receive_context, cp, buffer_ptr(&input), |
| block_size); |
| cp = buffer_ptr(&incoming_packet); |
| packet_length = GET_32BIT(cp); |
| if (packet_length < 1 + 4 || packet_length > 256 * 1024) { |
| #ifdef PACKET_DEBUG |
| buffer_dump(&incoming_packet); |
| #endif |
| packet_disconnect("Bad packet length %u.", packet_length); |
| } |
| DBG(debug("input: packet len %u", packet_length+4)); |
| buffer_consume(&input, block_size); |
| } |
| /* we have a partial packet of block_size bytes */ |
| need = 4 + packet_length - block_size; |
| DBG(debug("partial packet %d, need %d, maclen %d", block_size, |
| need, maclen)); |
| if (need % block_size != 0) |
| fatal("padding error: need %d block %d mod %d", |
| need, block_size, need % block_size); |
| /* |
| * check if the entire packet has been received and |
| * decrypt into incoming_packet |
| */ |
| if (buffer_len(&input) < need + maclen) |
| return SSH_MSG_NONE; |
| #ifdef PACKET_DEBUG |
| fprintf(stderr, "read_poll enc/full: "); |
| buffer_dump(&input); |
| #endif |
| cp = buffer_append_space(&incoming_packet, need); |
| cipher_crypt(&receive_context, cp, buffer_ptr(&input), need); |
| buffer_consume(&input, need); |
| /* |
| * compute MAC over seqnr and packet, |
| * increment sequence number for incoming packet |
| */ |
| if (mac && mac->enabled) { |
| macbuf = mac_compute(mac, p_read.seqnr, |
| buffer_ptr(&incoming_packet), |
| buffer_len(&incoming_packet)); |
| if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0) |
| packet_disconnect("Corrupted MAC on input."); |
| DBG(debug("MAC #%d ok", p_read.seqnr)); |
| buffer_consume(&input, mac->mac_len); |
| } |
| if (seqnr_p != NULL) |
| *seqnr_p = p_read.seqnr; |
| if (++p_read.seqnr == 0) |
| logit("incoming seqnr wraps around"); |
| if (++p_read.packets == 0) |
| if (!(datafellows & SSH_BUG_NOREKEY)) |
| fatal("XXX too many packets with same key"); |
| p_read.blocks += (packet_length + 4) / block_size; |
| |
| /* get padlen */ |
| cp = buffer_ptr(&incoming_packet); |
| padlen = cp[4]; |
| DBG(debug("input: padlen %d", padlen)); |
| if (padlen < 4) |
| packet_disconnect("Corrupted padlen %d on input.", padlen); |
| |
| /* skip packet size + padlen, discard padding */ |
| buffer_consume(&incoming_packet, 4 + 1); |
| buffer_consume_end(&incoming_packet, padlen); |
| |
| DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet))); |
| if (comp && comp->enabled) { |
| buffer_clear(&compression_buffer); |
| buffer_uncompress(&incoming_packet, &compression_buffer); |
| buffer_clear(&incoming_packet); |
| buffer_append(&incoming_packet, buffer_ptr(&compression_buffer), |
| buffer_len(&compression_buffer)); |
| DBG(debug("input: len after de-compress %d", |
| buffer_len(&incoming_packet))); |
| } |
| /* |
| * get packet type, implies consume. |
| * return length of payload (without type field) |
| */ |
| type = buffer_get_char(&incoming_packet); |
| if (type < SSH2_MSG_MIN || type >= SSH2_MSG_LOCAL_MIN) |
| packet_disconnect("Invalid ssh2 packet type: %d", type); |
| if (type == SSH2_MSG_NEWKEYS) |
| set_newkeys(MODE_IN); |
| else if (type == SSH2_MSG_USERAUTH_SUCCESS && !server_side) |
| packet_enable_delayed_compress(); |
| #ifdef PACKET_DEBUG |
| fprintf(stderr, "read/plain[%d]:\r\n", type); |
| buffer_dump(&incoming_packet); |
| #endif |
| /* reset for next packet */ |
| packet_length = 0; |
| return type; |
| } |
| |
| int |
| packet_read_poll_seqnr(u_int32_t *seqnr_p) |
| { |
| u_int reason, seqnr; |
| u_char type; |
| char *msg; |
| |
| for (;;) { |
| if (compat20) { |
| type = packet_read_poll2(seqnr_p); |
| if (type) |
| DBG(debug("received packet type %d", type)); |
| switch (type) { |
| case SSH2_MSG_IGNORE: |
| break; |
| case SSH2_MSG_DEBUG: |
| packet_get_char(); |
| msg = packet_get_string(NULL); |
| debug("Remote: %.900s", msg); |
| xfree(msg); |
| msg = packet_get_string(NULL); |
| xfree(msg); |
| break; |
| case SSH2_MSG_DISCONNECT: |
| reason = packet_get_int(); |
| msg = packet_get_string(NULL); |
| logit("Received disconnect from %s: %u: %.400s", |
| get_remote_ipaddr(), reason, msg); |
| xfree(msg); |
| cleanup_exit(255); |
| break; |
| case SSH2_MSG_UNIMPLEMENTED: |
| seqnr = packet_get_int(); |
| debug("Received SSH2_MSG_UNIMPLEMENTED for %u", |
| seqnr); |
| break; |
| default: |
| return type; |
| } |
| } else { |
| type = packet_read_poll1(); |
| switch (type) { |
| case SSH_MSG_IGNORE: |
| break; |
| case SSH_MSG_DEBUG: |
| msg = packet_get_string(NULL); |
| debug("Remote: %.900s", msg); |
| xfree(msg); |
| break; |
| case SSH_MSG_DISCONNECT: |
| msg = packet_get_string(NULL); |
| logit("Received disconnect from %s: %.400s", |
| get_remote_ipaddr(), msg); |
| cleanup_exit(255); |
| xfree(msg); |
| break; |
| default: |
| if (type) |
| DBG(debug("received packet type %d", type)); |
| return type; |
| } |
| } |
| } |
| } |
| |
| int |
| packet_read_poll(void) |
| { |
| return packet_read_poll_seqnr(NULL); |
| } |
| |
| /* |
| * Buffers the given amount of input characters. This is intended to be used |
| * together with packet_read_poll. |
| */ |
| |
| void |
| packet_process_incoming(const char *buf, u_int len) |
| { |
| buffer_append(&input, buf, len); |
| } |
| |
| /* Returns a character from the packet. */ |
| |
| u_int |
| packet_get_char(void) |
| { |
| char ch; |
| |
| buffer_get(&incoming_packet, &ch, 1); |
| return (u_char) ch; |
| } |
| |
| /* Returns an integer from the packet data. */ |
| |
| u_int |
| packet_get_int(void) |
| { |
| return buffer_get_int(&incoming_packet); |
| } |
| |
| /* |
| * Returns an arbitrary precision integer from the packet data. The integer |
| * must have been initialized before this call. |
| */ |
| |
| void |
| packet_get_bignum(BIGNUM * value) |
| { |
| buffer_get_bignum(&incoming_packet, value); |
| } |
| |
| void |
| packet_get_bignum2(BIGNUM * value) |
| { |
| buffer_get_bignum2(&incoming_packet, value); |
| } |
| |
| void * |
| packet_get_raw(u_int *length_ptr) |
| { |
| u_int bytes = buffer_len(&incoming_packet); |
| |
| if (length_ptr != NULL) |
| *length_ptr = bytes; |
| return buffer_ptr(&incoming_packet); |
| } |
| |
| int |
| packet_remaining(void) |
| { |
| return buffer_len(&incoming_packet); |
| } |
| |
| /* |
| * Returns a string from the packet data. The string is allocated using |
| * xmalloc; it is the responsibility of the calling program to free it when |
| * no longer needed. The length_ptr argument may be NULL, or point to an |
| * integer into which the length of the string is stored. |
| */ |
| |
| void * |
| packet_get_string(u_int *length_ptr) |
| { |
| return buffer_get_string(&incoming_packet, length_ptr); |
| } |
| |
| /* |
| * Sends a diagnostic message from the server to the client. This message |
| * can be sent at any time (but not while constructing another message). The |
| * message is printed immediately, but only if the client is being executed |
| * in verbose mode. These messages are primarily intended to ease debugging |
| * authentication problems. The length of the formatted message must not |
| * exceed 1024 bytes. This will automatically call packet_write_wait. |
| */ |
| |
| void |
| packet_send_debug(const char *fmt,...) |
| { |
| char buf[1024]; |
| va_list args; |
| |
| if (compat20 && (datafellows & SSH_BUG_DEBUG)) |
| return; |
| |
| va_start(args, fmt); |
| vsnprintf(buf, sizeof(buf), fmt, args); |
| va_end(args); |
| |
| if (compat20) { |
| packet_start(SSH2_MSG_DEBUG); |
| packet_put_char(0); /* bool: always display */ |
| packet_put_cstring(buf); |
| packet_put_cstring(""); |
| } else { |
| packet_start(SSH_MSG_DEBUG); |
| packet_put_cstring(buf); |
| } |
| packet_send(); |
| packet_write_wait(); |
| } |
| |
| /* |
| * Logs the error plus constructs and sends a disconnect packet, closes the |
| * connection, and exits. This function never returns. The error message |
| * should not contain a newline. The length of the formatted message must |
| * not exceed 1024 bytes. |
| */ |
| |
| void |
| packet_disconnect(const char *fmt,...) |
| { |
| char buf[1024]; |
| va_list args; |
| static int disconnecting = 0; |
| |
| if (disconnecting) /* Guard against recursive invocations. */ |
| fatal("packet_disconnect called recursively."); |
| disconnecting = 1; |
| |
| /* |
| * Format the message. Note that the caller must make sure the |
| * message is of limited size. |
| */ |
| va_start(args, fmt); |
| vsnprintf(buf, sizeof(buf), fmt, args); |
| va_end(args); |
| |
| /* Display the error locally */ |
| logit("Disconnecting: %.100s", buf); |
| |
| /* Send the disconnect message to the other side, and wait for it to get sent. */ |
| if (compat20) { |
| packet_start(SSH2_MSG_DISCONNECT); |
| packet_put_int(SSH2_DISCONNECT_PROTOCOL_ERROR); |
| packet_put_cstring(buf); |
| packet_put_cstring(""); |
| } else { |
| packet_start(SSH_MSG_DISCONNECT); |
| packet_put_cstring(buf); |
| } |
| packet_send(); |
| packet_write_wait(); |
| |
| /* Stop listening for connections. */ |
| channel_close_all(); |
| |
| /* Close the connection. */ |
| packet_close(); |
| cleanup_exit(255); |
| } |
| |
| /* Checks if there is any buffered output, and tries to write some of the output. */ |
| |
| void |
| packet_write_poll(void) |
| { |
| int len = buffer_len(&output); |
| |
| if (len > 0) { |
| len = write(connection_out, buffer_ptr(&output), len); |
| if (len <= 0) { |
| if (errno == EAGAIN) |
| return; |
| else |
| fatal("Write failed: %.100s", strerror(errno)); |
| } |
| buffer_consume(&output, len); |
| } |
| } |
| |
| /* |
| * Calls packet_write_poll repeatedly until all pending output data has been |
| * written. |
| */ |
| |
| void |
| packet_write_wait(void) |
| { |
| fd_set *setp; |
| |
| setp = (fd_set *)xcalloc(howmany(connection_out + 1, NFDBITS), |
| sizeof(fd_mask)); |
| packet_write_poll(); |
| while (packet_have_data_to_write()) { |
| memset(setp, 0, howmany(connection_out + 1, NFDBITS) * |
| sizeof(fd_mask)); |
| FD_SET(connection_out, setp); |
| while (select(connection_out + 1, NULL, setp, NULL, NULL) == -1 && |
| (errno == EAGAIN || errno == EINTR)) |
| ; |
| packet_write_poll(); |
| } |
| xfree(setp); |
| } |
| |
| /* Returns true if there is buffered data to write to the connection. */ |
| |
| int |
| packet_have_data_to_write(void) |
| { |
| return buffer_len(&output) != 0; |
| } |
| |
| /* Returns true if there is not too much data to write to the connection. */ |
| |
| int |
| packet_not_very_much_data_to_write(void) |
| { |
| if (interactive_mode) |
| return buffer_len(&output) < 16384; |
| else |
| return buffer_len(&output) < 128 * 1024; |
| } |
| |
| |
| static void |
| packet_set_tos(int interactive) |
| { |
| #if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN) |
| int tos = interactive ? IPTOS_LOWDELAY : IPTOS_THROUGHPUT; |
| |
| if (!packet_connection_is_on_socket() || |
| !packet_connection_is_ipv4()) |
| return; |
| if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, &tos, |
| sizeof(tos)) < 0) |
| error("setsockopt IP_TOS %d: %.100s:", |
| tos, strerror(errno)); |
| #endif |
| } |
| |
| /* Informs that the current session is interactive. Sets IP flags for that. */ |
| |
| void |
| packet_set_interactive(int interactive) |
| { |
| static int called = 0; |
| |
| if (called) |
| return; |
| called = 1; |
| |
| /* Record that we are in interactive mode. */ |
| interactive_mode = interactive; |
| |
| /* Only set socket options if using a socket. */ |
| if (!packet_connection_is_on_socket()) |
| return; |
| set_nodelay(connection_in); |
| packet_set_tos(interactive); |
| } |
| |
| /* Returns true if the current connection is interactive. */ |
| |
| int |
| packet_is_interactive(void) |
| { |
| return interactive_mode; |
| } |
| |
| int |
| packet_set_maxsize(u_int s) |
| { |
| static int called = 0; |
| |
| if (called) { |
| logit("packet_set_maxsize: called twice: old %d new %d", |
| max_packet_size, s); |
| return -1; |
| } |
| if (s < 4 * 1024 || s > 1024 * 1024) { |
| logit("packet_set_maxsize: bad size %d", s); |
| return -1; |
| } |
| called = 1; |
| debug("packet_set_maxsize: setting to %d", s); |
| max_packet_size = s; |
| return s; |
| } |
| |
| /* roundup current message to pad bytes */ |
| void |
| packet_add_padding(u_char pad) |
| { |
| extra_pad = pad; |
| } |
| |
| /* |
| * 9.2. Ignored Data Message |
| * |
| * byte SSH_MSG_IGNORE |
| * string data |
| * |
| * All implementations MUST understand (and ignore) this message at any |
| * time (after receiving the protocol version). No implementation is |
| * required to send them. This message can be used as an additional |
| * protection measure against advanced traffic analysis techniques. |
| */ |
| void |
| packet_send_ignore(int nbytes) |
| { |
| u_int32_t rnd = 0; |
| int i; |
| |
| packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE); |
| packet_put_int(nbytes); |
| for (i = 0; i < nbytes; i++) { |
| if (i % 4 == 0) |
| rnd = arc4random(); |
| packet_put_char(rnd & 0xff); |
| rnd >>= 8; |
| } |
| } |
| |
| #define MAX_PACKETS (1U<<31) |
| int |
| packet_need_rekeying(void) |
| { |
| if (datafellows & SSH_BUG_NOREKEY) |
| return 0; |
| return |
| (p_send.packets > MAX_PACKETS) || |
| (p_read.packets > MAX_PACKETS) || |
| (max_blocks_out && (p_send.blocks > max_blocks_out)) || |
| (max_blocks_in && (p_read.blocks > max_blocks_in)); |
| } |
| |
| void |
| packet_set_rekey_limit(u_int32_t bytes) |
| { |
| rekey_limit = bytes; |
| } |
| |
| void |
| packet_set_server(void) |
| { |
| server_side = 1; |
| } |
| |
| void |
| packet_set_authenticated(void) |
| { |
| after_authentication = 1; |
| } |