/* $OpenBSD: packet.c,v 1.200 2015/01/13 19:31:40 markus Exp $ */ /* * Author: Tatu Ylonen * Copyright (c) 1995 Tatu Ylonen , 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 #include "openbsd-compat/sys-queue.h" #include #include #ifdef HAVE_SYS_TIME_H # include #endif #include #include #include #include #include #include #include #include #include #include #include #include "xmalloc.h" #include "buffer.h" #include "packet.h" #include "crc32.h" #include "compress.h" #include "deattack.h" #include "compat.h" #include "ssh1.h" #include "ssh2.h" #include "cipher.h" #include "key.h" #include "kex.h" #include "digest.h" #include "mac.h" #include "log.h" #include "canohost.h" #include "misc.h" #include "channels.h" #include "ssh.h" #include "ssherr.h" #include "roaming.h" #ifdef PACKET_DEBUG #define DBG(x) x #else #define DBG(x) #endif #define PACKET_MAX_SIZE (256 * 1024) struct packet_state { u_int32_t seqnr; u_int32_t packets; u_int64_t blocks; u_int64_t bytes; }; struct packet { TAILQ_ENTRY(packet) next; u_char type; Buffer payload; }; struct session_state { /* * 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. */ int connection_in; int connection_out; /* Protocol flags for the remote side. */ u_int remote_protocol_flags; /* Encryption context for receiving data. Only used for decryption. */ CipherContext receive_context; /* Encryption context for sending data. Only used for encryption. */ 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. */ Buffer outgoing_packet; /* Buffer for the incoming packet currently being processed. */ Buffer incoming_packet; /* Scratch buffer for packet compression/decompression. */ Buffer compression_buffer; int compression_buffer_ready; /* * Flag indicating whether packet compression/decompression is * enabled. */ int packet_compression; /* default maximum packet size */ u_int max_packet_size; /* Flag indicating whether this module has been initialized. */ int initialized; /* Set to true if the connection is interactive. */ int interactive_mode; /* Set to true if we are the server side. */ int server_side; /* Set to true if we are authenticated. */ int after_authentication; int keep_alive_timeouts; /* The maximum time that we will wait to send or receive a packet */ int packet_timeout_ms; /* Session key information for Encryption and MAC */ Newkeys *newkeys[MODE_MAX]; struct packet_state p_read, p_send; /* Volume-based rekeying */ u_int64_t max_blocks_in, max_blocks_out; u_int32_t rekey_limit; /* Time-based rekeying */ time_t rekey_interval; /* how often in seconds */ time_t rekey_time; /* time of last rekeying */ /* Session key for protocol v1 */ u_char ssh1_key[SSH_SESSION_KEY_LENGTH]; u_int ssh1_keylen; /* roundup current message to extra_pad bytes */ u_char extra_pad; /* XXX discard incoming data after MAC error */ u_int packet_discard; Mac *packet_discard_mac; /* Used in packet_read_poll2() */ u_int packlen; /* Used in packet_send2 */ int rekeying; /* Used in packet_set_interactive */ int set_interactive_called; /* Used in packet_set_maxsize */ int set_maxsize_called; TAILQ_HEAD(, packet) outgoing; }; static struct session_state *active_state, *backup_state; static struct session_state * alloc_session_state(void) { struct session_state *s = xcalloc(1, sizeof(*s)); s->connection_in = -1; s->connection_out = -1; s->max_packet_size = 32768; s->packet_timeout_ms = -1; return s; } /* * 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) { const Cipher *none = cipher_by_name("none"); int r; if (none == NULL) fatal("packet_set_connection: cannot load cipher 'none'"); if (active_state == NULL) active_state = alloc_session_state(); active_state->connection_in = fd_in; active_state->connection_out = fd_out; if ((r = cipher_init(&active_state->send_context, none, (const u_char *)"", 0, NULL, 0, CIPHER_ENCRYPT)) != 0 || (r = cipher_init(&active_state->receive_context, none, (const u_char *)"", 0, NULL, 0, CIPHER_DECRYPT)) != 0) fatal("%s: cipher_init: %s", __func__, ssh_err(r)); active_state->newkeys[MODE_IN] = active_state->newkeys[MODE_OUT] = NULL; if (!active_state->initialized) { active_state->initialized = 1; buffer_init(&active_state->input); buffer_init(&active_state->output); buffer_init(&active_state->outgoing_packet); buffer_init(&active_state->incoming_packet); TAILQ_INIT(&active_state->outgoing); active_state->p_send.packets = active_state->p_read.packets = 0; } } void packet_set_timeout(int timeout, int count) { if (timeout <= 0 || count <= 0) { active_state->packet_timeout_ms = -1; return; } if ((INT_MAX / 1000) / count < timeout) active_state->packet_timeout_ms = INT_MAX; else active_state->packet_timeout_ms = timeout * count * 1000; } static void packet_stop_discard(void) { if (active_state->packet_discard_mac) { char buf[1024]; memset(buf, 'a', sizeof(buf)); while (buffer_len(&active_state->incoming_packet) < PACKET_MAX_SIZE) buffer_append(&active_state->incoming_packet, buf, sizeof(buf)); (void) mac_compute(active_state->packet_discard_mac, active_state->p_read.seqnr, buffer_ptr(&active_state->incoming_packet), PACKET_MAX_SIZE, NULL, 0); } logit("Finished discarding for %.200s", get_remote_ipaddr()); cleanup_exit(255); } static void packet_start_discard(Enc *enc, Mac *mac, u_int packet_length, u_int discard) { if (enc == NULL || !cipher_is_cbc(enc->cipher) || (mac && mac->etm)) packet_disconnect("Packet corrupt"); if (packet_length != PACKET_MAX_SIZE && mac && mac->enabled) active_state->packet_discard_mac = mac; if (buffer_len(&active_state->input) >= discard) packet_stop_discard(); active_state->packet_discard = discard - buffer_len(&active_state->input); } /* 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 (active_state->connection_in == active_state->connection_out) return 1; fromlen = sizeof(from); memset(&from, 0, sizeof(from)); if (getpeername(active_state->connection_in, (struct sockaddr *)&from, &fromlen) < 0) return 0; tolen = sizeof(to); memset(&to, 0, sizeof(to)); if (getpeername(active_state->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; int r; if (mode == MODE_OUT) cc = &active_state->send_context; else cc = &active_state->receive_context; if ((r = cipher_get_keyiv(cc, iv, len)) != 0) fatal("%s: cipher_get_keyiv: %s", __func__, ssh_err(r)); } int packet_get_keycontext(int mode, u_char *dat) { CipherContext *cc; if (mode == MODE_OUT) cc = &active_state->send_context; else cc = &active_state->receive_context; return (cipher_get_keycontext(cc, dat)); } void packet_set_keycontext(int mode, u_char *dat) { CipherContext *cc; if (mode == MODE_OUT) cc = &active_state->send_context; else cc = &active_state->receive_context; cipher_set_keycontext(cc, dat); } int packet_get_keyiv_len(int mode) { CipherContext *cc; if (mode == MODE_OUT) cc = &active_state->send_context; else cc = &active_state->receive_context; return (cipher_get_keyiv_len(cc)); } void packet_set_iv(int mode, u_char *dat) { CipherContext *cc; int r; if (mode == MODE_OUT) cc = &active_state->send_context; else cc = &active_state->receive_context; if ((r = cipher_set_keyiv(cc, dat)) != 0) fatal("%s: cipher_set_keyiv: %s", __func__, ssh_err(r)); } int packet_get_ssh1_cipher(void) { return (cipher_get_number(active_state->receive_context.cipher)); } void packet_get_state(int mode, u_int32_t *seqnr, u_int64_t *blocks, u_int32_t *packets, u_int64_t *bytes) { struct packet_state *state; state = (mode == MODE_IN) ? &active_state->p_read : &active_state->p_send; if (seqnr) *seqnr = state->seqnr; if (blocks) *blocks = state->blocks; if (packets) *packets = state->packets; if (bytes) *bytes = state->bytes; } void packet_set_state(int mode, u_int32_t seqnr, u_int64_t blocks, u_int32_t packets, u_int64_t bytes) { struct packet_state *state; state = (mode == MODE_IN) ? &active_state->p_read : &active_state->p_send; state->seqnr = seqnr; state->blocks = blocks; state->packets = packets; state->bytes = bytes; } static int packet_connection_af(void) { struct sockaddr_storage to; socklen_t tolen = sizeof(to); memset(&to, 0, sizeof(to)); if (getsockname(active_state->connection_out, (struct sockaddr *)&to, &tolen) < 0) return 0; #ifdef IPV4_IN_IPV6 if (to.ss_family == AF_INET6 && IN6_IS_ADDR_V4MAPPED(&((struct sockaddr_in6 *)&to)->sin6_addr)) return AF_INET; #endif return to.ss_family; } /* Sets the connection into non-blocking mode. */ void packet_set_nonblocking(void) { /* Set the socket into non-blocking mode. */ set_nonblock(active_state->connection_in); if (active_state->connection_out != active_state->connection_in) set_nonblock(active_state->connection_out); } /* Returns the socket used for reading. */ int packet_get_connection_in(void) { return active_state->connection_in; } /* Returns the descriptor used for writing. */ int packet_get_connection_out(void) { return active_state->connection_out; } /* Closes the connection and clears and frees internal data structures. */ void packet_close(void) { if (!active_state->initialized) return; active_state->initialized = 0; if (active_state->connection_in == active_state->connection_out) { shutdown(active_state->connection_out, SHUT_RDWR); close(active_state->connection_out); } else { close(active_state->connection_in); close(active_state->connection_out); } buffer_free(&active_state->input); buffer_free(&active_state->output); buffer_free(&active_state->outgoing_packet); buffer_free(&active_state->incoming_packet); if (active_state->compression_buffer_ready) { buffer_free(&active_state->compression_buffer); buffer_compress_uninit(); } cipher_cleanup(&active_state->send_context); cipher_cleanup(&active_state->receive_context); } /* Sets remote side protocol flags. */ void packet_set_protocol_flags(u_int protocol_flags) { active_state->remote_protocol_flags = protocol_flags; } /* Returns the remote protocol flags set earlier by the above function. */ u_int packet_get_protocol_flags(void) { return active_state->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 (active_state->compression_buffer_ready == 1) return; active_state->compression_buffer_ready = 1; buffer_init(&active_state->compression_buffer); } void packet_start_compression(int level) { if (active_state->packet_compression && !compat20) fatal("Compression already enabled."); active_state->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) { const Cipher *cipher = cipher_by_number(number); int r; 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(active_state->ssh1_key, key, keylen); active_state->ssh1_keylen = keylen; if ((r = cipher_init(&active_state->send_context, cipher, key, keylen, NULL, 0, CIPHER_ENCRYPT)) != 0 || (r = cipher_init(&active_state->receive_context, cipher, key, keylen, NULL, 0, CIPHER_DECRYPT)) != 0) fatal("%s: cipher_init: %s", __func__, ssh_err(r)); } u_int packet_get_encryption_key(u_char *key) { if (key == NULL) return (active_state->ssh1_keylen); memcpy(key, active_state->ssh1_key, active_state->ssh1_keylen); return (active_state->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(&active_state->outgoing_packet); buffer_append(&active_state->outgoing_packet, buf, len); } /* Append payload. */ void packet_put_char(int value) { char ch = value; buffer_append(&active_state->outgoing_packet, &ch, 1); } void packet_put_int(u_int value) { buffer_put_int(&active_state->outgoing_packet, value); } void packet_put_int64(u_int64_t value) { buffer_put_int64(&active_state->outgoing_packet, value); } void packet_put_string(const void *buf, u_int len) { buffer_put_string(&active_state->outgoing_packet, buf, len); } void packet_put_cstring(const char *str) { buffer_put_cstring(&active_state->outgoing_packet, str); } void packet_put_raw(const void *buf, u_int len) { buffer_append(&active_state->outgoing_packet, buf, len); } #ifdef WITH_OPENSSL void packet_put_bignum(BIGNUM * value) { buffer_put_bignum(&active_state->outgoing_packet, value); } void packet_put_bignum2(BIGNUM * value) { buffer_put_bignum2(&active_state->outgoing_packet, value); } #endif #ifdef OPENSSL_HAS_ECC void packet_put_ecpoint(const EC_GROUP *curve, const EC_POINT *point) { buffer_put_ecpoint(&active_state->outgoing_packet, curve, point); } #endif /* * 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 (active_state->packet_compression) { buffer_clear(&active_state->compression_buffer); /* Skip padding. */ buffer_consume(&active_state->outgoing_packet, 8); /* padding */ buffer_append(&active_state->compression_buffer, "\0\0\0\0\0\0\0\0", 8); buffer_compress(&active_state->outgoing_packet, &active_state->compression_buffer); buffer_clear(&active_state->outgoing_packet); buffer_append(&active_state->outgoing_packet, buffer_ptr(&active_state->compression_buffer), buffer_len(&active_state->compression_buffer)); } /* Compute packet length without padding (add checksum, remove padding). */ len = buffer_len(&active_state->outgoing_packet) + 4 - 8; /* Insert padding. Initialized to zero in packet_start1() */ padding = 8 - len % 8; if (!active_state->send_context.plaintext) { cp = buffer_ptr(&active_state->outgoing_packet); for (i = 0; i < padding; i++) { if (i % 4 == 0) rnd = arc4random(); cp[7 - i] = rnd & 0xff; rnd >>= 8; } } buffer_consume(&active_state->outgoing_packet, 8 - padding); /* Add check bytes. */ checksum = ssh_crc32(buffer_ptr(&active_state->outgoing_packet), buffer_len(&active_state->outgoing_packet)); put_u32(buf, checksum); buffer_append(&active_state->outgoing_packet, buf, 4); #ifdef PACKET_DEBUG fprintf(stderr, "packet_send plain: "); buffer_dump(&active_state->outgoing_packet); #endif /* Append to output. */ put_u32(buf, len); buffer_append(&active_state->output, buf, 4); cp = buffer_append_space(&active_state->output, buffer_len(&active_state->outgoing_packet)); if (cipher_crypt(&active_state->send_context, 0, cp, buffer_ptr(&active_state->outgoing_packet), buffer_len(&active_state->outgoing_packet), 0, 0) != 0) fatal("%s: cipher_crypt failed", __func__); #ifdef PACKET_DEBUG fprintf(stderr, "encrypted: "); buffer_dump(&active_state->output); #endif active_state->p_send.packets++; active_state->p_send.bytes += len + buffer_len(&active_state->outgoing_packet); buffer_clear(&active_state->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 r, crypt_type; debug2("set_newkeys: mode %d", mode); if (mode == MODE_OUT) { cc = &active_state->send_context; crypt_type = CIPHER_ENCRYPT; active_state->p_send.packets = active_state->p_send.blocks = 0; max_blocks = &active_state->max_blocks_out; } else { cc = &active_state->receive_context; crypt_type = CIPHER_DECRYPT; active_state->p_read.packets = active_state->p_read.blocks = 0; max_blocks = &active_state->max_blocks_in; } if (active_state->newkeys[mode] != NULL) { debug("set_newkeys: rekeying"); cipher_cleanup(cc); enc = &active_state->newkeys[mode]->enc; mac = &active_state->newkeys[mode]->mac; comp = &active_state->newkeys[mode]->comp; mac_clear(mac); explicit_bzero(enc->iv, enc->iv_len); explicit_bzero(enc->key, enc->key_len); explicit_bzero(mac->key, mac->key_len); free(enc->name); free(enc->iv); free(enc->key); free(mac->name); free(mac->key); free(comp->name); free(active_state->newkeys[mode]); } active_state->newkeys[mode] = kex_get_newkeys(mode); if (active_state->newkeys[mode] == NULL) fatal("newkeys: no keys for mode %d", mode); enc = &active_state->newkeys[mode]->enc; mac = &active_state->newkeys[mode]->mac; comp = &active_state->newkeys[mode]->comp; if (cipher_authlen(enc->cipher) == 0 && mac_init(mac) == 0) mac->enabled = 1; DBG(debug("cipher_init_context: %d", mode)); if ((r = cipher_init(cc, enc->cipher, enc->key, enc->key_len, enc->iv, enc->iv_len, crypt_type)) != 0) fatal("%s: cipher_init: %s", __func__, ssh_err(r)); /* Deleting the keys does not gain extra security */ /* explicit_bzero(enc->iv, enc->block_size); explicit_bzero(enc->key, enc->key_len); explicit_bzero(mac->key, mac->key_len); */ if ((comp->type == COMP_ZLIB || (comp->type == COMP_DELAYED && active_state->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 (active_state->rekey_limit) *max_blocks = MIN(*max_blocks, active_state->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. */ active_state->after_authentication = 1; for (mode = 0; mode < MODE_MAX; mode++) { /* protocol error: USERAUTH_SUCCESS received before NEWKEYS */ if (active_state->newkeys[mode] == NULL) continue; comp = &active_state->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[SSH_DIGEST_MAX_LENGTH]; u_char padlen, pad = 0; u_int i, len, authlen = 0, aadlen = 0; u_int32_t rnd = 0; Enc *enc = NULL; Mac *mac = NULL; Comp *comp = NULL; int block_size; int r; if (active_state->newkeys[MODE_OUT] != NULL) { enc = &active_state->newkeys[MODE_OUT]->enc; mac = &active_state->newkeys[MODE_OUT]->mac; comp = &active_state->newkeys[MODE_OUT]->comp; /* disable mac for authenticated encryption */ if ((authlen = cipher_authlen(enc->cipher)) != 0) mac = NULL; } block_size = enc ? enc->block_size : 8; aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0; cp = buffer_ptr(&active_state->outgoing_packet); type = cp[5]; #ifdef PACKET_DEBUG fprintf(stderr, "plain: "); buffer_dump(&active_state->outgoing_packet); #endif if (comp && comp->enabled) { len = buffer_len(&active_state->outgoing_packet); /* skip header, compress only payload */ buffer_consume(&active_state->outgoing_packet, 5); buffer_clear(&active_state->compression_buffer); buffer_compress(&active_state->outgoing_packet, &active_state->compression_buffer); buffer_clear(&active_state->outgoing_packet); buffer_append(&active_state->outgoing_packet, "\0\0\0\0\0", 5); buffer_append(&active_state->outgoing_packet, buffer_ptr(&active_state->compression_buffer), buffer_len(&active_state->compression_buffer)); DBG(debug("compression: raw %d compressed %d", len, buffer_len(&active_state->outgoing_packet))); } /* sizeof (packet_len + pad_len + payload) */ len = buffer_len(&active_state->outgoing_packet); /* * calc size of padding, alloc space, get random data, * minimum padding is 4 bytes */ len -= aadlen; /* packet length is not encrypted for EtM modes */ padlen = block_size - (len % block_size); if (padlen < 4) padlen += block_size; if (active_state->extra_pad) { /* will wrap if extra_pad+padlen > 255 */ active_state->extra_pad = roundup(active_state->extra_pad, block_size); pad = active_state->extra_pad - ((len + padlen) % active_state->extra_pad); DBG(debug3("%s: adding %d (len %d padlen %d extra_pad %d)", __func__, pad, len, padlen, active_state->extra_pad)); padlen += pad; active_state->extra_pad = 0; } cp = buffer_append_space(&active_state->outgoing_packet, padlen); if (enc && !active_state->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 */ explicit_bzero(cp, padlen); } /* sizeof (packet_len + pad_len + payload + padding) */ len = buffer_len(&active_state->outgoing_packet); cp = buffer_ptr(&active_state->outgoing_packet); /* packet_length includes payload, padding and padding length field */ put_u32(cp, len - 4); cp[4] = padlen; DBG(debug("send: len %d (includes padlen %d, aadlen %d)", len, padlen, aadlen)); /* compute MAC over seqnr and packet(length fields, payload, padding) */ if (mac && mac->enabled && !mac->etm) { if ((r = mac_compute(mac, active_state->p_send.seqnr, buffer_ptr(&active_state->outgoing_packet), len, macbuf, sizeof(macbuf))) != 0) fatal("%s: mac_compute: %s", __func__, ssh_err(r)); DBG(debug("done calc MAC out #%d", active_state->p_send.seqnr)); } /* encrypt packet and append to output buffer. */ cp = buffer_append_space(&active_state->output, len + authlen); if (cipher_crypt(&active_state->send_context, active_state->p_send.seqnr, cp, buffer_ptr(&active_state->outgoing_packet), len - aadlen, aadlen, authlen) != 0) fatal("%s: cipher_crypt failed", __func__); /* append unencrypted MAC */ if (mac && mac->enabled) { if (mac->etm) { /* EtM: compute mac over aadlen + cipher text */ if ((r = mac_compute(mac, active_state->p_send.seqnr, cp, len, macbuf, sizeof(macbuf))) != 0) fatal("%s: mac_compute: %s", __func__, ssh_err(r)); DBG(debug("done calc MAC(EtM) out #%d", active_state->p_send.seqnr)); } buffer_append(&active_state->output, macbuf, mac->mac_len); } #ifdef PACKET_DEBUG fprintf(stderr, "encrypted: "); buffer_dump(&active_state->output); #endif /* increment sequence number for outgoing packets */ if (++active_state->p_send.seqnr == 0) logit("outgoing seqnr wraps around"); if (++active_state->p_send.packets == 0) if (!(datafellows & SSH_BUG_NOREKEY)) fatal("XXX too many packets with same key"); active_state->p_send.blocks += len / block_size; active_state->p_send.bytes += len; buffer_clear(&active_state->outgoing_packet); if (type == SSH2_MSG_NEWKEYS) set_newkeys(MODE_OUT); else if (type == SSH2_MSG_USERAUTH_SUCCESS && active_state->server_side) packet_enable_delayed_compress(); } static void packet_send2(void) { struct packet *p; u_char type, *cp; cp = buffer_ptr(&active_state->outgoing_packet); type = cp[5]; /* during rekeying we can only send key exchange messages */ if (active_state->rekeying) { if ((type < SSH2_MSG_TRANSPORT_MIN) || (type > SSH2_MSG_TRANSPORT_MAX) || (type == SSH2_MSG_SERVICE_REQUEST) || (type == SSH2_MSG_SERVICE_ACCEPT)) { debug("enqueue packet: %u", type); p = xcalloc(1, sizeof(*p)); p->type = type; memcpy(&p->payload, &active_state->outgoing_packet, sizeof(Buffer)); buffer_init(&active_state->outgoing_packet); TAILQ_INSERT_TAIL(&active_state->outgoing, p, next); return; } } /* rekeying starts with sending KEXINIT */ if (type == SSH2_MSG_KEXINIT) active_state->rekeying = 1; packet_send2_wrapped(); /* after a NEWKEYS message we can send the complete queue */ if (type == SSH2_MSG_NEWKEYS) { active_state->rekeying = 0; active_state->rekey_time = monotime(); while ((p = TAILQ_FIRST(&active_state->outgoing))) { type = p->type; debug("dequeue packet: %u", type); buffer_free(&active_state->outgoing_packet); memcpy(&active_state->outgoing_packet, &p->payload, sizeof(Buffer)); TAILQ_REMOVE(&active_state->outgoing, p, next); free(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, ret, cont, ms_remain = 0; fd_set *setp; char buf[8192]; struct timeval timeout, start, *timeoutp = NULL; DBG(debug("packet_read()")); setp = (fd_set *)xcalloc(howmany(active_state->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) { free(setp); return type; } /* * Otherwise, wait for some data to arrive, add it to the * buffer, and try again. */ memset(setp, 0, howmany(active_state->connection_in + 1, NFDBITS) * sizeof(fd_mask)); FD_SET(active_state->connection_in, setp); if (active_state->packet_timeout_ms > 0) { ms_remain = active_state->packet_timeout_ms; timeoutp = &timeout; } /* Wait for some data to arrive. */ for (;;) { if (active_state->packet_timeout_ms != -1) { ms_to_timeval(&timeout, ms_remain); gettimeofday(&start, NULL); } if ((ret = select(active_state->connection_in + 1, setp, NULL, NULL, timeoutp)) >= 0) break; if (errno != EAGAIN && errno != EINTR && errno != EWOULDBLOCK) break; if (active_state->packet_timeout_ms == -1) continue; ms_subtract_diff(&start, &ms_remain); if (ms_remain <= 0) { ret = 0; break; } } if (ret == 0) { logit("Connection to %.200s timed out while " "waiting to read", get_remote_ipaddr()); cleanup_exit(255); } /* Read data from the socket. */ do { cont = 0; len = roaming_read(active_state->connection_in, buf, sizeof(buf), &cont); } while (len == 0 && cont); 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(&active_state->input) < 4 + 8) return SSH_MSG_NONE; /* Get length of incoming packet. */ cp = buffer_ptr(&active_state->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(&active_state->input) < 4 + padded_len) return SSH_MSG_NONE; /* The entire packet is in buffer. */ /* Consume packet length. */ buffer_consume(&active_state->input, 4); /* * Cryptographic attack detector for ssh * (C)1998 CORE-SDI, Buenos Aires Argentina * Ariel Futoransky(futo@core-sdi.com) */ if (!active_state->receive_context.plaintext) { switch (detect_attack(buffer_ptr(&active_state->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(&active_state->incoming_packet); cp = buffer_append_space(&active_state->incoming_packet, padded_len); if (cipher_crypt(&active_state->receive_context, 0, cp, buffer_ptr(&active_state->input), padded_len, 0, 0) != 0) fatal("%s: cipher_crypt failed", __func__); buffer_consume(&active_state->input, padded_len); #ifdef PACKET_DEBUG fprintf(stderr, "read_poll plain: "); buffer_dump(&active_state->incoming_packet); #endif /* Compute packet checksum. */ checksum = ssh_crc32(buffer_ptr(&active_state->incoming_packet), buffer_len(&active_state->incoming_packet) - 4); /* Skip padding. */ buffer_consume(&active_state->incoming_packet, 8 - len % 8); /* Test check bytes. */ if (len != buffer_len(&active_state->incoming_packet)) packet_disconnect("packet_read_poll1: len %d != buffer_len %d.", len, buffer_len(&active_state->incoming_packet)); cp = (u_char *)buffer_ptr(&active_state->incoming_packet) + len - 4; stored_checksum = get_u32(cp); if (checksum != stored_checksum) packet_disconnect("Corrupted check bytes on input."); buffer_consume_end(&active_state->incoming_packet, 4); if (active_state->packet_compression) { buffer_clear(&active_state->compression_buffer); buffer_uncompress(&active_state->incoming_packet, &active_state->compression_buffer); buffer_clear(&active_state->incoming_packet); buffer_append(&active_state->incoming_packet, buffer_ptr(&active_state->compression_buffer), buffer_len(&active_state->compression_buffer)); } active_state->p_read.packets++; active_state->p_read.bytes += padded_len + 4; type = buffer_get_char(&active_state->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) { u_int padlen, need; u_char type, *cp, macbuf[SSH_DIGEST_MAX_LENGTH]; u_int maclen, authlen = 0, aadlen = 0, block_size; int r; Enc *enc = NULL; Mac *mac = NULL; Comp *comp = NULL; if (active_state->packet_discard) return SSH_MSG_NONE; if (active_state->newkeys[MODE_IN] != NULL) { enc = &active_state->newkeys[MODE_IN]->enc; mac = &active_state->newkeys[MODE_IN]->mac; comp = &active_state->newkeys[MODE_IN]->comp; /* disable mac for authenticated encryption */ if ((authlen = cipher_authlen(enc->cipher)) != 0) mac = NULL; } maclen = mac && mac->enabled ? mac->mac_len : 0; block_size = enc ? enc->block_size : 8; aadlen = (mac && mac->enabled && mac->etm) || authlen ? 4 : 0; if (aadlen && active_state->packlen == 0) { if (cipher_get_length(&active_state->receive_context, &active_state->packlen, active_state->p_read.seqnr, buffer_ptr(&active_state->input), buffer_len(&active_state->input)) != 0) return SSH_MSG_NONE; if (active_state->packlen < 1 + 4 || active_state->packlen > PACKET_MAX_SIZE) { #ifdef PACKET_DEBUG buffer_dump(&active_state->input); #endif logit("Bad packet length %u.", active_state->packlen); packet_disconnect("Packet corrupt"); } buffer_clear(&active_state->incoming_packet); } else if (active_state->packlen == 0) { /* * check if input size is less than the cipher block size, * decrypt first block and extract length of incoming packet */ if (buffer_len(&active_state->input) < block_size) return SSH_MSG_NONE; buffer_clear(&active_state->incoming_packet); cp = buffer_append_space(&active_state->incoming_packet, block_size); if (cipher_crypt(&active_state->receive_context, active_state->p_read.seqnr, cp, buffer_ptr(&active_state->input), block_size, 0, 0) != 0) fatal("Decryption integrity check failed"); cp = buffer_ptr(&active_state->incoming_packet); active_state->packlen = get_u32(cp); if (active_state->packlen < 1 + 4 || active_state->packlen > PACKET_MAX_SIZE) { #ifdef PACKET_DEBUG buffer_dump(&active_state->incoming_packet); #endif logit("Bad packet length %u.", active_state->packlen); packet_start_discard(enc, mac, active_state->packlen, PACKET_MAX_SIZE); return SSH_MSG_NONE; } buffer_consume(&active_state->input, block_size); } DBG(debug("input: packet len %u", active_state->packlen+4)); if (aadlen) { /* only the payload is encrypted */ need = active_state->packlen; } else { /* * the payload size and the payload are encrypted, but we * have a partial packet of block_size bytes */ need = 4 + active_state->packlen - block_size; } DBG(debug("partial packet: block %d, need %d, maclen %d, authlen %d," " aadlen %d", block_size, need, maclen, authlen, aadlen)); if (need % block_size != 0) { logit("padding error: need %d block %d mod %d", need, block_size, need % block_size); packet_start_discard(enc, mac, active_state->packlen, PACKET_MAX_SIZE - block_size); return SSH_MSG_NONE; } /* * check if the entire packet has been received and * decrypt into incoming_packet: * 'aadlen' bytes are unencrypted, but authenticated. * 'need' bytes are encrypted, followed by either * 'authlen' bytes of authentication tag or * 'maclen' bytes of message authentication code. */ if (buffer_len(&active_state->input) < aadlen + need + authlen + maclen) return SSH_MSG_NONE; #ifdef PACKET_DEBUG fprintf(stderr, "read_poll enc/full: "); buffer_dump(&active_state->input); #endif /* EtM: compute mac over encrypted input */ if (mac && mac->enabled && mac->etm) if ((r = mac_compute(mac, active_state->p_read.seqnr, buffer_ptr(&active_state->input), aadlen + need, macbuf, sizeof(macbuf))) != 0) fatal("%s: mac_compute: %s", __func__, ssh_err(r)); cp = buffer_append_space(&active_state->incoming_packet, aadlen + need); if (cipher_crypt(&active_state->receive_context, active_state->p_read.seqnr, cp, buffer_ptr(&active_state->input), need, aadlen, authlen) != 0) fatal("Decryption integrity check failed"); buffer_consume(&active_state->input, aadlen + need + authlen); /* * compute MAC over seqnr and packet, * increment sequence number for incoming packet */ if (mac && mac->enabled) { if (!mac->etm) if ((r = mac_compute(mac, active_state->p_read.seqnr, buffer_ptr(&active_state->incoming_packet), buffer_len(&active_state->incoming_packet), macbuf, sizeof(macbuf))) != 0) fatal("%s: mac_compute: %s", __func__, ssh_err(r)); if (timingsafe_bcmp(macbuf, buffer_ptr(&active_state->input), mac->mac_len) != 0) { logit("Corrupted MAC on input."); if (need > PACKET_MAX_SIZE) fatal("internal error need %d", need); packet_start_discard(enc, mac, active_state->packlen, PACKET_MAX_SIZE - need); return SSH_MSG_NONE; } DBG(debug("MAC #%d ok", active_state->p_read.seqnr)); buffer_consume(&active_state->input, mac->mac_len); } /* XXX now it's safe to use fatal/packet_disconnect */ if (seqnr_p != NULL) *seqnr_p = active_state->p_read.seqnr; if (++active_state->p_read.seqnr == 0) logit("incoming seqnr wraps around"); if (++active_state->p_read.packets == 0) if (!(datafellows & SSH_BUG_NOREKEY)) fatal("XXX too many packets with same key"); active_state->p_read.blocks += (active_state->packlen + 4) / block_size; active_state->p_read.bytes += active_state->packlen + 4; /* get padlen */ cp = buffer_ptr(&active_state->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(&active_state->incoming_packet, 4 + 1); buffer_consume_end(&active_state->incoming_packet, padlen); DBG(debug("input: len before de-compress %d", buffer_len(&active_state->incoming_packet))); if (comp && comp->enabled) { buffer_clear(&active_state->compression_buffer); buffer_uncompress(&active_state->incoming_packet, &active_state->compression_buffer); buffer_clear(&active_state->incoming_packet); buffer_append(&active_state->incoming_packet, buffer_ptr(&active_state->compression_buffer), buffer_len(&active_state->compression_buffer)); DBG(debug("input: len after de-compress %d", buffer_len(&active_state->incoming_packet))); } /* * get packet type, implies consume. * return length of payload (without type field) */ type = buffer_get_char(&active_state->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 && !active_state->server_side) packet_enable_delayed_compress(); #ifdef PACKET_DEBUG fprintf(stderr, "read/plain[%d]:\r\n", type); buffer_dump(&active_state->incoming_packet); #endif /* reset for next packet */ active_state->packlen = 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) { active_state->keep_alive_timeouts = 0; DBG(debug("received packet type %d", type)); } switch (type) { case SSH2_MSG_IGNORE: debug3("Received SSH2_MSG_IGNORE"); break; case SSH2_MSG_DEBUG: packet_get_char(); msg = packet_get_string(NULL); debug("Remote: %.900s", msg); free(msg); msg = packet_get_string(NULL); free(msg); break; case SSH2_MSG_DISCONNECT: reason = packet_get_int(); msg = packet_get_string(NULL); /* Ignore normal client exit notifications */ do_log2(active_state->server_side && reason == SSH2_DISCONNECT_BY_APPLICATION ? SYSLOG_LEVEL_INFO : SYSLOG_LEVEL_ERROR, "Received disconnect from %s: %u: %.400s", get_remote_ipaddr(), reason, msg); free(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_NONE: return SSH_MSG_NONE; case SSH_MSG_IGNORE: break; case SSH_MSG_DEBUG: msg = packet_get_string(NULL); debug("Remote: %.900s", msg); free(msg); break; case SSH_MSG_DISCONNECT: msg = packet_get_string(NULL); error("Received disconnect from %s: %.400s", get_remote_ipaddr(), msg); cleanup_exit(255); break; default: DBG(debug("received packet type %d", type)); return type; } } } } /* * 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) { if (active_state->packet_discard) { active_state->keep_alive_timeouts = 0; /* ?? */ if (len >= active_state->packet_discard) packet_stop_discard(); active_state->packet_discard -= len; return; } buffer_append(&active_state->input, buf, len); } /* Returns a character from the packet. */ u_int packet_get_char(void) { char ch; buffer_get(&active_state->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(&active_state->incoming_packet); } /* Returns an 64 bit integer from the packet data. */ u_int64_t packet_get_int64(void) { return buffer_get_int64(&active_state->incoming_packet); } /* * Returns an arbitrary precision integer from the packet data. The integer * must have been initialized before this call. */ #ifdef WITH_OPENSSL void packet_get_bignum(BIGNUM * value) { buffer_get_bignum(&active_state->incoming_packet, value); } void packet_get_bignum2(BIGNUM * value) { buffer_get_bignum2(&active_state->incoming_packet, value); } #ifdef OPENSSL_HAS_ECC void packet_get_ecpoint(const EC_GROUP *curve, EC_POINT *point) { buffer_get_ecpoint(&active_state->incoming_packet, curve, point); } #endif void * packet_get_raw(u_int *length_ptr) { u_int bytes = buffer_len(&active_state->incoming_packet); if (length_ptr != NULL) *length_ptr = bytes; return buffer_ptr(&active_state->incoming_packet); } #endif int packet_remaining(void) { return buffer_len(&active_state->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(&active_state->incoming_packet, length_ptr); } const void * packet_get_string_ptr(u_int *length_ptr) { return buffer_get_string_ptr(&active_state->incoming_packet, length_ptr); } /* Ensures the returned string has no embedded \0 characters in it. */ char * packet_get_cstring(u_int *length_ptr) { return buffer_get_cstring(&active_state->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(&active_state->output); int cont; if (len > 0) { cont = 0; len = roaming_write(active_state->connection_out, buffer_ptr(&active_state->output), len, &cont); if (len == -1) { if (errno == EINTR || errno == EAGAIN || errno == EWOULDBLOCK) return; fatal("Write failed: %.100s", strerror(errno)); } if (len == 0 && !cont) fatal("Write connection closed"); buffer_consume(&active_state->output, len); } } /* * Calls packet_write_poll repeatedly until all pending output data has been * written. */ void packet_write_wait(void) { fd_set *setp; int ret, ms_remain = 0; struct timeval start, timeout, *timeoutp = NULL; setp = (fd_set *)xcalloc(howmany(active_state->connection_out + 1, NFDBITS), sizeof(fd_mask)); packet_write_poll(); while (packet_have_data_to_write()) { memset(setp, 0, howmany(active_state->connection_out + 1, NFDBITS) * sizeof(fd_mask)); FD_SET(active_state->connection_out, setp); if (active_state->packet_timeout_ms > 0) { ms_remain = active_state->packet_timeout_ms; timeoutp = &timeout; } for (;;) { if (active_state->packet_timeout_ms != -1) { ms_to_timeval(&timeout, ms_remain); gettimeofday(&start, NULL); } if ((ret = select(active_state->connection_out + 1, NULL, setp, NULL, timeoutp)) >= 0) break; if (errno != EAGAIN && errno != EINTR && errno != EWOULDBLOCK) break; if (active_state->packet_timeout_ms == -1) continue; ms_subtract_diff(&start, &ms_remain); if (ms_remain <= 0) { ret = 0; break; } } if (ret == 0) { logit("Connection to %.200s timed out while " "waiting to write", get_remote_ipaddr()); cleanup_exit(255); } packet_write_poll(); } free(setp); } /* Returns true if there is buffered data to write to the connection. */ int packet_have_data_to_write(void) { return buffer_len(&active_state->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 (active_state->interactive_mode) return buffer_len(&active_state->output) < 16384; else return buffer_len(&active_state->output) < 128 * 1024; } static void packet_set_tos(int tos) { #ifndef IP_TOS_IS_BROKEN if (!packet_connection_is_on_socket()) return; switch (packet_connection_af()) { # ifdef IP_TOS case AF_INET: debug3("%s: set IP_TOS 0x%02x", __func__, tos); if (setsockopt(active_state->connection_in, IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) < 0) error("setsockopt IP_TOS %d: %.100s:", tos, strerror(errno)); break; # endif /* IP_TOS */ # ifdef IPV6_TCLASS case AF_INET6: debug3("%s: set IPV6_TCLASS 0x%02x", __func__, tos); if (setsockopt(active_state->connection_in, IPPROTO_IPV6, IPV6_TCLASS, &tos, sizeof(tos)) < 0) error("setsockopt IPV6_TCLASS %d: %.100s:", tos, strerror(errno)); break; # endif /* IPV6_TCLASS */ } #endif /* IP_TOS_IS_BROKEN */ } /* Informs that the current session is interactive. Sets IP flags for that. */ void packet_set_interactive(int interactive, int qos_interactive, int qos_bulk) { if (active_state->set_interactive_called) return; active_state->set_interactive_called = 1; /* Record that we are in interactive mode. */ active_state->interactive_mode = interactive; /* Only set socket options if using a socket. */ if (!packet_connection_is_on_socket()) return; set_nodelay(active_state->connection_in); packet_set_tos(interactive ? qos_interactive : qos_bulk); } /* Returns true if the current connection is interactive. */ int packet_is_interactive(void) { return active_state->interactive_mode; } int packet_set_maxsize(u_int s) { if (active_state->set_maxsize_called) { logit("packet_set_maxsize: called twice: old %d new %d", active_state->max_packet_size, s); return -1; } if (s < 4 * 1024 || s > 1024 * 1024) { logit("packet_set_maxsize: bad size %d", s); return -1; } active_state->set_maxsize_called = 1; debug("packet_set_maxsize: setting to %d", s); active_state->max_packet_size = s; return s; } int packet_inc_alive_timeouts(void) { return ++active_state->keep_alive_timeouts; } void packet_set_alive_timeouts(int ka) { active_state->keep_alive_timeouts = ka; } u_int packet_get_maxsize(void) { return active_state->max_packet_size; } /* roundup current message to pad bytes */ void packet_add_padding(u_char pad) { active_state->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 (active_state->p_send.packets > MAX_PACKETS) || (active_state->p_read.packets > MAX_PACKETS) || (active_state->max_blocks_out && (active_state->p_send.blocks > active_state->max_blocks_out)) || (active_state->max_blocks_in && (active_state->p_read.blocks > active_state->max_blocks_in)) || (active_state->rekey_interval != 0 && active_state->rekey_time + active_state->rekey_interval <= monotime()); } void packet_set_rekey_limits(u_int32_t bytes, time_t seconds) { debug3("rekey after %lld bytes, %d seconds", (long long)bytes, (int)seconds); active_state->rekey_limit = bytes; active_state->rekey_interval = seconds; /* * We set the time here so that in post-auth privsep slave we count * from the completion of the authentication. */ active_state->rekey_time = monotime(); } time_t packet_get_rekey_timeout(void) { time_t seconds; seconds = active_state->rekey_time + active_state->rekey_interval - monotime(); return (seconds <= 0 ? 1 : seconds); } void packet_set_server(void) { active_state->server_side = 1; } void packet_set_authenticated(void) { active_state->after_authentication = 1; } void * packet_get_input(void) { return (void *)&active_state->input; } void * packet_get_output(void) { return (void *)&active_state->output; } void * packet_get_newkeys(int mode) { return (void *)active_state->newkeys[mode]; } /* * Save the state for the real connection, and use a separate state when * resuming a suspended connection. */ void packet_backup_state(void) { struct session_state *tmp; close(active_state->connection_in); active_state->connection_in = -1; close(active_state->connection_out); active_state->connection_out = -1; if (backup_state) tmp = backup_state; else tmp = alloc_session_state(); backup_state = active_state; active_state = tmp; } /* * Swap in the old state when resuming a connecion. */ void packet_restore_state(void) { struct session_state *tmp; void *buf; u_int len; tmp = backup_state; backup_state = active_state; active_state = tmp; active_state->connection_in = backup_state->connection_in; backup_state->connection_in = -1; active_state->connection_out = backup_state->connection_out; backup_state->connection_out = -1; len = buffer_len(&backup_state->input); if (len > 0) { buf = buffer_ptr(&backup_state->input); buffer_append(&active_state->input, buf, len); buffer_clear(&backup_state->input); add_recv_bytes(len); } } /* Reset after_authentication and reset compression in post-auth privsep */ void packet_set_postauth(void) { Comp *comp; int mode; debug("%s: called", __func__); /* This was set in net child, but is not visible in user child */ active_state->after_authentication = 1; active_state->rekeying = 0; for (mode = 0; mode < MODE_MAX; mode++) { if (active_state->newkeys[mode] == NULL) continue; comp = &active_state->newkeys[mode]->comp; if (comp && comp->enabled) packet_init_compression(); } }