diff options
Diffstat (limited to 'crypto/openssh/packet.c')
| -rw-r--r-- | crypto/openssh/packet.c | 1609 |
1 files changed, 0 insertions, 1609 deletions
diff --git a/crypto/openssh/packet.c b/crypto/openssh/packet.c deleted file mode 100644 index ab5a010..0000000 --- a/crypto/openssh/packet.c +++ /dev/null @@ -1,1609 +0,0 @@ -/* $OpenBSD: packet.c,v 1.145 2006/09/19 21:14:08 markus 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 <sys/types.h> -#include "openbsd-compat/sys-queue.h" -#include <sys/param.h> -#include <sys/socket.h> -#ifdef HAVE_SYS_TIME_H -# include <sys/time.h> -#endif - -#include <netinet/in_systm.h> -#include <netinet/in.h> -#include <netinet/ip.h> -#include <arpa/inet.h> - -#include <errno.h> -#include <stdarg.h> -#include <stdio.h> -#include <stdlib.h> -#include <string.h> -#include <unistd.h> -#include <signal.h> - -#include "xmalloc.h" -#include "buffer.h" -#include "packet.h" -#include "crc32.h" -#include "compress.h" -#include "deattack.h" -#include "channels.h" -#include "compat.h" -#include "ssh1.h" -#include "ssh2.h" -#include "cipher.h" -#include "key.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_u32(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_u32(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 happens 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++) { - /* protocol error: USERAUTH_SUCCESS received before NEWKEYS */ - if (newkeys[mode] == NULL) - continue; - 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_u32(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, 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_u32(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) { - switch (detect_attack(buffer_ptr(&input), padded_len)) { - case DEATTACK_DETECTED: - packet_disconnect("crc32 compensation attack: " - "network attack detected"); - case DEATTACK_DOS_DETECTED: - packet_disconnect("deattack denial of " - "service 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_u32(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_u32(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((u_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; -} |
