/* $OpenBSD: packet.c,v 1.174 2011/12/07 05:44:38 djm 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "xmalloc.h" #include "buffer.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" #include "packet.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; u_int64_t max_blocks_in, max_blocks_out; u_int32_t rekey_limit; /* 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; }; struct ssh * ssh_alloc_session_state(void) { struct ssh *ssh = xcalloc(1, sizeof(*ssh)); struct session_state *state = xcalloc(1, sizeof(*state)); state->connection_in = -1; state->connection_out = -1; state->max_packet_size = 32768; state->packet_timeout_ms = -1; ssh->state = state; return ssh; } /* * Sets the descriptors used for communication. Disables encryption until * packet_set_encryption_key is called. */ struct ssh * ssh_packet_set_connection(struct ssh *ssh, int fd_in, int fd_out) { struct session_state *state; Cipher *none = cipher_by_name("none"); if (none == NULL) fatal("packet_set_connection: cannot load cipher 'none'"); if (ssh == NULL) ssh = ssh_alloc_session_state(); state = ssh->state; state->connection_in = fd_in; state->connection_out = fd_out; cipher_init(&state->send_context, none, (const u_char *)"", 0, NULL, 0, CIPHER_ENCRYPT); cipher_init(&state->receive_context, none, (const u_char *)"", 0, NULL, 0, CIPHER_DECRYPT); state->newkeys[MODE_IN] = state->newkeys[MODE_OUT] = NULL; if (!state->initialized) { state->initialized = 1; buffer_init(&state->input); buffer_init(&state->output); buffer_init(&state->outgoing_packet); buffer_init(&state->incoming_packet); TAILQ_INIT(&state->outgoing); TAILQ_INIT(&ssh->private_keys); TAILQ_INIT(&ssh->public_keys); state->p_send.packets = state->p_read.packets = 0; } return ssh; } void ssh_packet_set_timeout(struct ssh *ssh, int timeout, int count) { struct session_state *state = ssh->state; if (timeout <= 0 || count <= 0) { state->packet_timeout_ms = -1; return; } if ((INT_MAX / 1000) / count < timeout) state->packet_timeout_ms = INT_MAX; else state->packet_timeout_ms = timeout * count * 1000; } void ssh_packet_stop_discard(struct ssh *ssh) { struct session_state *state = ssh->state; if (state->packet_discard_mac) { char buf[1024]; memset(buf, 'a', sizeof(buf)); while (buffer_len(&state->incoming_packet) < PACKET_MAX_SIZE) buffer_append(&state->incoming_packet, buf, sizeof(buf)); (void) mac_compute(state->packet_discard_mac, state->p_read.seqnr, buffer_ptr(&state->incoming_packet), PACKET_MAX_SIZE); } logit("Finished discarding for %.200s", get_remote_ipaddr()); cleanup_exit(255); } void ssh_packet_start_discard(struct ssh *ssh, Enc *enc, Mac *mac, u_int packet_length, u_int discard) { struct session_state *state = ssh->state; if (enc == NULL || !cipher_is_cbc(enc->cipher)) ssh_packet_disconnect(ssh, "Packet corrupt"); if (packet_length != PACKET_MAX_SIZE && mac && mac->enabled) state->packet_discard_mac = mac; if (buffer_len(&state->input) >= discard) ssh_packet_stop_discard(ssh); state->packet_discard = discard - buffer_len(&state->input); } /* Returns 1 if remote host is connected via socket, 0 if not. */ int ssh_packet_connection_is_on_socket(struct ssh *ssh) { struct session_state *state = ssh->state; struct sockaddr_storage from, to; socklen_t fromlen, tolen; /* filedescriptors in and out are the same, so it's a socket */ if (state->connection_in == state->connection_out) return 1; fromlen = sizeof(from); memset(&from, 0, sizeof(from)); if (getpeername(state->connection_in, (struct sockaddr *)&from, &fromlen) < 0) return 0; tolen = sizeof(to); memset(&to, 0, sizeof(to)); if (getpeername(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 ssh_packet_get_keyiv(struct ssh *ssh, int mode, u_char *iv, u_int len) { CipherContext *cc; if (mode == MODE_OUT) cc = &ssh->state->send_context; else cc = &ssh->state->receive_context; cipher_get_keyiv(cc, iv, len); } int ssh_packet_get_keycontext(struct ssh *ssh, int mode, u_char *dat) { CipherContext *cc; if (mode == MODE_OUT) cc = &ssh->state->send_context; else cc = &ssh->state->receive_context; return (cipher_get_keycontext(cc, dat)); } void ssh_packet_set_keycontext(struct ssh *ssh, int mode, u_char *dat) { CipherContext *cc; if (mode == MODE_OUT) cc = &ssh->state->send_context; else cc = &ssh->state->receive_context; cipher_set_keycontext(cc, dat); } int ssh_packet_get_keyiv_len(struct ssh *ssh, int mode) { CipherContext *cc; if (mode == MODE_OUT) cc = &ssh->state->send_context; else cc = &ssh->state->receive_context; return (cipher_get_keyiv_len(cc)); } void ssh_packet_set_iv(struct ssh *ssh, int mode, u_char *dat) { CipherContext *cc; if (mode == MODE_OUT) cc = &ssh->state->send_context; else cc = &ssh->state->receive_context; cipher_set_keyiv(cc, dat); } int ssh_packet_get_ssh1_cipher(struct ssh *ssh) { return (cipher_get_number(ssh->state->receive_context.cipher)); } void ssh_packet_get_state(struct ssh *ssh, int mode, u_int32_t *seqnr, u_int64_t *blocks, u_int32_t *packets, u_int64_t *bytes) { struct packet_state *pstate; pstate = (mode == MODE_IN) ? &ssh->state->p_read : &ssh->state->p_send; if (seqnr) *seqnr = pstate->seqnr; if (blocks) *blocks = pstate->blocks; if (packets) *packets = pstate->packets; if (bytes) *bytes = pstate->bytes; } void ssh_packet_set_state(struct ssh *ssh, int mode, u_int32_t seqnr, u_int64_t blocks, u_int32_t packets, u_int64_t bytes) { struct packet_state *pstate; pstate = (mode == MODE_IN) ? &ssh->state->p_read : &ssh->state->p_send; pstate->seqnr = seqnr; pstate->blocks = blocks; pstate->packets = packets; pstate->bytes = bytes; } int ssh_packet_connection_af(struct ssh *ssh) { struct sockaddr_storage to; socklen_t tolen = sizeof(to); memset(&to, 0, sizeof(to)); if (getsockname(ssh->state->connection_out, (struct sockaddr *)&to, &tolen) < 0) return 0; return to.ss_family; } /* Sets the connection into non-blocking mode. */ void ssh_packet_set_nonblocking(struct ssh *ssh) { /* Set the socket into non-blocking mode. */ set_nonblock(ssh->state->connection_in); if (ssh->state->connection_out != ssh->state->connection_in) set_nonblock(ssh->state->connection_out); } /* Returns the socket used for reading. */ int ssh_packet_get_connection_in(struct ssh *ssh) { return ssh->state->connection_in; } /* Returns the descriptor used for writing. */ int ssh_packet_get_connection_out(struct ssh *ssh) { return ssh->state->connection_out; } /* Closes the connection and clears and frees internal data structures. */ void ssh_packet_close(struct ssh *ssh) { struct session_state *state = ssh->state; if (!state->initialized) return; state->initialized = 0; if (state->connection_in == state->connection_out) { shutdown(state->connection_out, SHUT_RDWR); close(state->connection_out); } else { close(state->connection_in); close(state->connection_out); } buffer_free(&state->input); buffer_free(&state->output); buffer_free(&state->outgoing_packet); buffer_free(&state->incoming_packet); if (state->compression_buffer_ready) { buffer_free(&state->compression_buffer); buffer_compress_uninit(); } cipher_cleanup(&state->send_context); cipher_cleanup(&state->receive_context); } /* Sets remote side protocol flags. */ void ssh_packet_set_protocol_flags(struct ssh *ssh, u_int protocol_flags) { ssh->state->remote_protocol_flags = protocol_flags; } /* Returns the remote protocol flags set earlier by the above function. */ u_int ssh_packet_get_protocol_flags(struct ssh *ssh) { return ssh->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. */ void ssh_packet_init_compression(struct ssh *ssh) { if (ssh->state->compression_buffer_ready == 1) return; ssh->state->compression_buffer_ready = 1; buffer_init(&ssh->state->compression_buffer); } void ssh_packet_start_compression(struct ssh *ssh, int level) { if (ssh->state->packet_compression && !compat20) fatal("Compression already enabled."); ssh->state->packet_compression = 1; ssh_packet_init_compression(ssh); 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 ssh_packet_set_encryption_key(struct ssh *ssh, const u_char *key, u_int keylen, int number) { struct session_state *state = ssh->state; 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(state->ssh1_key, key, keylen); state->ssh1_keylen = keylen; cipher_init(&state->send_context, cipher, key, keylen, NULL, 0, CIPHER_ENCRYPT); cipher_init(&state->receive_context, cipher, key, keylen, NULL, 0, CIPHER_DECRYPT); } u_int ssh_packet_get_encryption_key(struct ssh *ssh, u_char *key) { if (key == NULL) return (ssh->state->ssh1_keylen); memcpy(key, ssh->state->ssh1_key, ssh->state->ssh1_keylen); return (ssh->state->ssh1_keylen); } /* Start constructing a packet to send. */ void ssh_packet_start(struct ssh *ssh, 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(&ssh->state->outgoing_packet); buffer_append(&ssh->state->outgoing_packet, buf, len); } /* Append payload. */ void ssh_packet_put_char(struct ssh *ssh, int value) { char ch = value; buffer_append(&ssh->state->outgoing_packet, &ch, 1); } void ssh_packet_put_int(struct ssh *ssh, u_int value) { buffer_put_int(&ssh->state->outgoing_packet, value); } void ssh_packet_put_int64(struct ssh *ssh, u_int64_t value) { buffer_put_int64(&ssh->state->outgoing_packet, value); } void ssh_packet_put_string(struct ssh *ssh, const void *buf, u_int len) { buffer_put_string(&ssh->state->outgoing_packet, buf, len); } void ssh_packet_put_cstring(struct ssh *ssh, const char *str) { buffer_put_cstring(&ssh->state->outgoing_packet, str); } void ssh_packet_put_raw(struct ssh *ssh, const void *buf, u_int len) { buffer_append(&ssh->state->outgoing_packet, buf, len); } void ssh_packet_put_bignum(struct ssh *ssh, BIGNUM * value) { buffer_put_bignum(&ssh->state->outgoing_packet, value); } void ssh_packet_put_bignum2(struct ssh *ssh, BIGNUM * value) { buffer_put_bignum2(&ssh->state->outgoing_packet, value); } void ssh_packet_put_ecpoint(struct ssh *ssh, const EC_GROUP *curve, const EC_POINT *point) { buffer_put_ecpoint(&ssh->state->outgoing_packet, curve, point); } /* * Finalizes and sends the packet. If the encryption key has been set, * encrypts the packet before sending. */ void ssh_packet_send1(struct ssh *ssh) { struct session_state *state = ssh->state; 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 (state->packet_compression) { buffer_clear(&state->compression_buffer); /* Skip padding. */ buffer_consume(&state->outgoing_packet, 8); /* padding */ buffer_append(&state->compression_buffer, "\0\0\0\0\0\0\0\0", 8); buffer_compress(&state->outgoing_packet, &state->compression_buffer); buffer_clear(&state->outgoing_packet); buffer_append(&state->outgoing_packet, buffer_ptr(&state->compression_buffer), buffer_len(&state->compression_buffer)); } /* Compute packet length without padding (add checksum, remove padding). */ len = buffer_len(&state->outgoing_packet) + 4 - 8; /* Insert padding. Initialized to zero in packet_start1() */ padding = 8 - len % 8; if (!state->send_context.plaintext) { cp = buffer_ptr(&state->outgoing_packet); for (i = 0; i < padding; i++) { if (i % 4 == 0) rnd = arc4random(); cp[7 - i] = rnd & 0xff; rnd >>= 8; } } buffer_consume(&state->outgoing_packet, 8 - padding); /* Add check bytes. */ checksum = ssh_crc32(buffer_ptr(&state->outgoing_packet), buffer_len(&state->outgoing_packet)); put_u32(buf, checksum); buffer_append(&state->outgoing_packet, buf, 4); #ifdef PACKET_DEBUG fprintf(stderr, "packet_send plain: "); buffer_dump(&state->outgoing_packet); #endif /* Append to output. */ put_u32(buf, len); buffer_append(&state->output, buf, 4); cp = buffer_append_space(&state->output, buffer_len(&state->outgoing_packet)); cipher_crypt(&state->send_context, cp, buffer_ptr(&state->outgoing_packet), buffer_len(&state->outgoing_packet)); #ifdef PACKET_DEBUG fprintf(stderr, "encrypted: "); buffer_dump(&state->output); #endif state->p_send.packets++; state->p_send.bytes += len + buffer_len(&state->outgoing_packet); buffer_clear(&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 ssh_set_newkeys(struct ssh *ssh, int mode) { struct session_state *state = ssh->state; 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 = &state->send_context; crypt_type = CIPHER_ENCRYPT; state->p_send.packets = state->p_send.blocks = 0; max_blocks = &state->max_blocks_out; } else { cc = &state->receive_context; crypt_type = CIPHER_DECRYPT; state->p_read.packets = state->p_read.blocks = 0; max_blocks = &state->max_blocks_in; } if (state->newkeys[mode] != NULL) { debug("set_newkeys: rekeying"); cipher_cleanup(cc); enc = &state->newkeys[mode]->enc; mac = &state->newkeys[mode]->mac; comp = &state->newkeys[mode]->comp; mac_clear(mac); xfree(enc->name); xfree(enc->iv); xfree(enc->key); xfree(mac->name); xfree(mac->key); xfree(comp->name); xfree(state->newkeys[mode]); } state->newkeys[mode] = kex_get_newkeys(ssh, mode); if (state->newkeys[mode] == NULL) fatal("newkeys: no keys for mode %d", mode); enc = &state->newkeys[mode]->enc; mac = &state->newkeys[mode]->mac; comp = &state->newkeys[mode]->comp; if (mac_init(mac) == 0) 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); memset(mac->key, 0, mac->key_len); */ if ((comp->type == COMP_ZLIB || (comp->type == COMP_DELAYED && state->after_authentication)) && comp->enabled == 0) { ssh_packet_init_compression(ssh); 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 (state->rekey_limit) *max_blocks = MIN(*max_blocks, 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. */ void ssh_packet_enable_delayed_compress(struct ssh *ssh) { struct session_state *state = ssh->state; Comp *comp = NULL; int mode; /* * Remember that we are past the authentication step, so rekeying * with COMP_DELAYED will turn on compression immediately. */ state->after_authentication = 1; for (mode = 0; mode < MODE_MAX; mode++) { /* protocol error: USERAUTH_SUCCESS received before NEWKEYS */ if (state->newkeys[mode] == NULL) continue; comp = &state->newkeys[mode]->comp; if (comp && !comp->enabled && comp->type == COMP_DELAYED) { ssh_packet_init_compression(ssh); 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) */ void ssh_packet_send2_wrapped(struct ssh *ssh) { struct session_state *state = ssh->state; 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 (state->newkeys[MODE_OUT] != NULL) { enc = &state->newkeys[MODE_OUT]->enc; mac = &state->newkeys[MODE_OUT]->mac; comp = &state->newkeys[MODE_OUT]->comp; } block_size = enc ? enc->block_size : 8; cp = buffer_ptr(&state->outgoing_packet); type = cp[5]; #ifdef PACKET_DEBUG fprintf(stderr, "plain: "); buffer_dump(&state->outgoing_packet); #endif if (comp && comp->enabled) { len = buffer_len(&state->outgoing_packet); /* skip header, compress only payload */ buffer_consume(&state->outgoing_packet, 5); buffer_clear(&state->compression_buffer); buffer_compress(&state->outgoing_packet, &state->compression_buffer); buffer_clear(&state->outgoing_packet); buffer_append(&state->outgoing_packet, "\0\0\0\0\0", 5); buffer_append(&state->outgoing_packet, buffer_ptr(&state->compression_buffer), buffer_len(&state->compression_buffer)); DBG(debug("compression: raw %d compressed %d", len, buffer_len(&state->outgoing_packet))); } /* sizeof (packet_len + pad_len + payload) */ len = buffer_len(&state->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 (state->extra_pad) { /* will wrap if extra_pad+padlen > 255 */ state->extra_pad = roundup(state->extra_pad, block_size); pad = state->extra_pad - ((len + padlen) % state->extra_pad); debug3("packet_send2: adding %d (len %d padlen %d extra_pad %d)", pad, len, padlen, state->extra_pad); padlen += pad; state->extra_pad = 0; } cp = buffer_append_space(&state->outgoing_packet, padlen); if (enc && !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 */ memset(cp, 0, padlen); } /* packet_length includes payload, padding and padding length field */ packet_length = buffer_len(&state->outgoing_packet) - 4; cp = buffer_ptr(&state->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, state->p_send.seqnr, buffer_ptr(&state->outgoing_packet), buffer_len(&state->outgoing_packet)); DBG(debug("done calc MAC out #%d", state->p_send.seqnr)); } /* encrypt packet and append to output buffer. */ cp = buffer_append_space(&state->output, buffer_len(&state->outgoing_packet)); cipher_crypt(&state->send_context, cp, buffer_ptr(&state->outgoing_packet), buffer_len(&state->outgoing_packet)); /* append unencrypted MAC */ if (mac && mac->enabled) buffer_append(&state->output, macbuf, mac->mac_len); #ifdef PACKET_DEBUG fprintf(stderr, "encrypted: "); buffer_dump(&state->output); #endif /* increment sequence number for outgoing packets */ if (++state->p_send.seqnr == 0) logit("outgoing seqnr wraps around"); if (++state->p_send.packets == 0) if (!(ssh->datafellows & SSH_BUG_NOREKEY)) fatal("XXX too many packets with same key"); state->p_send.blocks += (packet_length + 4) / block_size; state->p_send.bytes += packet_length + 4; buffer_clear(&state->outgoing_packet); if (type == SSH2_MSG_NEWKEYS) ssh_set_newkeys(ssh, MODE_OUT); else if (type == SSH2_MSG_USERAUTH_SUCCESS && state->server_side) ssh_packet_enable_delayed_compress(ssh); } void ssh_packet_send2(struct ssh *ssh) { struct session_state *state = ssh->state; struct packet *p; u_char type, *cp; cp = buffer_ptr(&state->outgoing_packet); type = cp[5]; /* during rekeying we can only send key exchange messages */ if (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 = xmalloc(sizeof(*p)); p->type = type; memcpy(&p->payload, &state->outgoing_packet, sizeof(Buffer)); buffer_init(&state->outgoing_packet); TAILQ_INSERT_TAIL(&state->outgoing, p, next); return; } } /* rekeying starts with sending KEXINIT */ if (type == SSH2_MSG_KEXINIT) state->rekeying = 1; ssh_packet_send2_wrapped(ssh); /* after a NEWKEYS message we can send the complete queue */ if (type == SSH2_MSG_NEWKEYS) { state->rekeying = 0; while ((p = TAILQ_FIRST(&state->outgoing))) { type = p->type; debug("dequeue packet: %u", type); buffer_free(&state->outgoing_packet); memcpy(&state->outgoing_packet, &p->payload, sizeof(Buffer)); TAILQ_REMOVE(&state->outgoing, p, next); xfree(p); ssh_packet_send2_wrapped(ssh); } } } void ssh_packet_send(struct ssh *ssh) { if (compat20) ssh_packet_send2(ssh); else ssh_packet_send1(ssh); 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 ssh_packet_read_seqnr(struct ssh *ssh, u_int32_t *seqnr_p) { struct session_state *state = ssh->state; int type, len, ret, ms_remain, cont; fd_set *setp; char buf[8192]; struct timeval timeout, start, *timeoutp = NULL; DBG(debug("packet_read()")); setp = (fd_set *)xcalloc(howmany(state->connection_in + 1, NFDBITS), sizeof(fd_mask)); /* Since we are blocking, ensure that all written packets have been sent. */ ssh_packet_write_wait(ssh); /* Stay in the loop until we have received a complete packet. */ for (;;) { /* Try to read a packet from the buffer. */ type = ssh_packet_read_poll_seqnr(ssh, seqnr_p); if (!compat20 && ( type == SSH_SMSG_SUCCESS || type == SSH_SMSG_FAILURE || type == SSH_CMSG_EOF || type == SSH_CMSG_EXIT_CONFIRMATION)) ssh_packet_check_eom(ssh); /* 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(state->connection_in + 1, NFDBITS) * sizeof(fd_mask)); FD_SET(state->connection_in, setp); if (state->packet_timeout_ms > 0) { ms_remain = state->packet_timeout_ms; timeoutp = &timeout; } /* Wait for some data to arrive. */ for (;;) { if (state->packet_timeout_ms != -1) { ms_to_timeval(&timeout, ms_remain); gettimeofday(&start, NULL); } if ((ret = select(state->connection_in + 1, setp, NULL, NULL, timeoutp)) >= 0) break; if (errno != EAGAIN && errno != EINTR) break; if (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(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. */ ssh_packet_process_incoming(ssh, buf, len); } /* NOTREACHED */ } int ssh_packet_read(struct ssh *ssh) { return ssh_packet_read_seqnr(ssh, 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 ssh_packet_read_expect(struct ssh *ssh, int expected_type) { int type; type = ssh_packet_read(ssh); if (type != expected_type) ssh_packet_disconnect(ssh, "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. */ int ssh_packet_read_poll1(struct ssh *ssh) { struct session_state *state = ssh->state; 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(&state->input) < 4 + 8) return SSH_MSG_NONE; /* Get length of incoming packet. */ cp = buffer_ptr(&state->input); len = get_u32(cp); if (len < 1 + 2 + 2 || len > 256 * 1024) ssh_packet_disconnect(ssh, "Bad packet length %u.", len); padded_len = (len + 8) & ~7; /* Check if the packet has been entirely received. */ if (buffer_len(&state->input) < 4 + padded_len) return SSH_MSG_NONE; /* The entire packet is in buffer. */ /* Consume packet length. */ buffer_consume(&state->input, 4); /* * Cryptographic attack detector for ssh * (C)1998 CORE-SDI, Buenos Aires Argentina * Ariel Futoransky(futo@core-sdi.com) */ if (!state->receive_context.plaintext) { switch (detect_attack(buffer_ptr(&state->input), padded_len)) { case DEATTACK_DETECTED: ssh_packet_disconnect(ssh, "crc32 compensation attack: network attack detected" ); case DEATTACK_DOS_DETECTED: ssh_packet_disconnect(ssh, "deattack denial of service detected"); } } /* Decrypt data to incoming_packet. */ buffer_clear(&state->incoming_packet); cp = buffer_append_space(&state->incoming_packet, padded_len); cipher_crypt(&state->receive_context, cp, buffer_ptr(&state->input), padded_len); buffer_consume(&state->input, padded_len); #ifdef PACKET_DEBUG fprintf(stderr, "read_poll plain: "); buffer_dump(&state->incoming_packet); #endif /* Compute packet checksum. */ checksum = ssh_crc32(buffer_ptr(&state->incoming_packet), buffer_len(&state->incoming_packet) - 4); /* Skip padding. */ buffer_consume(&state->incoming_packet, 8 - len % 8); /* Test check bytes. */ if (len != buffer_len(&state->incoming_packet)) ssh_packet_disconnect(ssh, "packet_read_poll1: len %d != buffer_len %d.", len, buffer_len(&state->incoming_packet)); cp = (u_char *)buffer_ptr(&state->incoming_packet) + len - 4; stored_checksum = get_u32(cp); if (checksum != stored_checksum) ssh_packet_disconnect(ssh, "Corrupted check bytes on input."); buffer_consume_end(&state->incoming_packet, 4); if (state->packet_compression) { buffer_clear(&state->compression_buffer); buffer_uncompress(&state->incoming_packet, &state->compression_buffer); buffer_clear(&state->incoming_packet); buffer_append(&state->incoming_packet, buffer_ptr(&state->compression_buffer), buffer_len(&state->compression_buffer)); } state->p_read.packets++; state->p_read.bytes += padded_len + 4; type = buffer_get_char(&state->incoming_packet); if (type < SSH_MSG_MIN || type > SSH_MSG_MAX) ssh_packet_disconnect(ssh, "Invalid ssh1 packet type: %d", type); return type; } int ssh_packet_read_poll2(struct ssh *ssh, u_int32_t *seqnr_p) { struct session_state *state = ssh->state; u_int padlen, need; u_char *macbuf, *cp, type; u_int maclen, block_size; Enc *enc = NULL; Mac *mac = NULL; Comp *comp = NULL; if (state->packet_discard) return SSH_MSG_NONE; if (state->newkeys[MODE_IN] != NULL) { enc = &state->newkeys[MODE_IN]->enc; mac = &state->newkeys[MODE_IN]->mac; comp = &state->newkeys[MODE_IN]->comp; } maclen = mac && mac->enabled ? mac->mac_len : 0; block_size = enc ? enc->block_size : 8; if (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(&state->input) < block_size) return SSH_MSG_NONE; buffer_clear(&state->incoming_packet); cp = buffer_append_space(&state->incoming_packet, block_size); cipher_crypt(&state->receive_context, cp, buffer_ptr(&state->input), block_size); cp = buffer_ptr(&state->incoming_packet); state->packlen = get_u32(cp); if (state->packlen < 1 + 4 || state->packlen > PACKET_MAX_SIZE) { #ifdef PACKET_DEBUG buffer_dump(&state->incoming_packet); #endif logit("Bad packet length %u.", state->packlen); ssh_packet_start_discard(ssh, enc, mac, state->packlen, PACKET_MAX_SIZE); return SSH_MSG_NONE; } DBG(debug("input: packet len %u", state->packlen+4)); buffer_consume(&state->input, block_size); } /* we have a partial packet of block_size bytes */ need = 4 + state->packlen - block_size; DBG(debug("partial packet %d, need %d, maclen %d", block_size, need, maclen)); if (need % block_size != 0) { logit("padding error: need %d block %d mod %d", need, block_size, need % block_size); ssh_packet_start_discard(ssh, enc, mac, state->packlen, PACKET_MAX_SIZE - block_size); return SSH_MSG_NONE; } /* * check if the entire packet has been received and * decrypt into incoming_packet */ if (buffer_len(&state->input) < need + maclen) return SSH_MSG_NONE; #ifdef PACKET_DEBUG fprintf(stderr, "read_poll enc/full: "); buffer_dump(&state->input); #endif cp = buffer_append_space(&state->incoming_packet, need); cipher_crypt(&state->receive_context, cp, buffer_ptr(&state->input), need); buffer_consume(&state->input, need); /* * compute MAC over seqnr and packet, * increment sequence number for incoming packet */ if (mac && mac->enabled) { macbuf = mac_compute(mac, state->p_read.seqnr, buffer_ptr(&state->incoming_packet), buffer_len(&state->incoming_packet)); if (timingsafe_bcmp(macbuf, buffer_ptr(&state->input), mac->mac_len) != 0) { logit("Corrupted MAC on input."); if (need > PACKET_MAX_SIZE) fatal("internal error need %d", need); ssh_packet_start_discard(ssh, enc, mac, state->packlen, PACKET_MAX_SIZE - need); return SSH_MSG_NONE; } DBG(debug("MAC #%d ok", state->p_read.seqnr)); buffer_consume(&state->input, mac->mac_len); } /* XXX now it's safe to use fatal/packet_disconnect */ if (seqnr_p != NULL) *seqnr_p = state->p_read.seqnr; if (++state->p_read.seqnr == 0) logit("incoming seqnr wraps around"); if (++state->p_read.packets == 0) if (!(ssh->datafellows & SSH_BUG_NOREKEY)) fatal("XXX too many packets with same key"); state->p_read.blocks += (state->packlen + 4) / block_size; state->p_read.bytes += state->packlen + 4; /* get padlen */ cp = buffer_ptr(&state->incoming_packet); padlen = cp[4]; DBG(debug("input: padlen %d", padlen)); if (padlen < 4) ssh_packet_disconnect(ssh, "Corrupted padlen %d on input.", padlen); /* skip packet size + padlen, discard padding */ buffer_consume(&state->incoming_packet, 4 + 1); buffer_consume_end(&state->incoming_packet, padlen); DBG(debug("input: len before de-compress %d", buffer_len(&state->incoming_packet))); if (comp && comp->enabled) { buffer_clear(&state->compression_buffer); buffer_uncompress(&state->incoming_packet, &state->compression_buffer); buffer_clear(&state->incoming_packet); buffer_append(&state->incoming_packet, buffer_ptr(&state->compression_buffer), buffer_len(&state->compression_buffer)); DBG(debug("input: len after de-compress %d", buffer_len(&state->incoming_packet))); } /* * get packet type, implies consume. * return length of payload (without type field) */ type = buffer_get_char(&state->incoming_packet); if (type < SSH2_MSG_MIN || type >= SSH2_MSG_LOCAL_MIN) ssh_packet_disconnect(ssh, "Invalid ssh2 packet type: %d", type); if (type == SSH2_MSG_NEWKEYS) ssh_set_newkeys(ssh, MODE_IN); else if (type == SSH2_MSG_USERAUTH_SUCCESS && !state->server_side) ssh_packet_enable_delayed_compress(ssh); #ifdef PACKET_DEBUG fprintf(stderr, "read/plain[%d]:\r\n", type); buffer_dump(&state->incoming_packet); #endif /* reset for next packet */ state->packlen = 0; return type; } int ssh_packet_read_poll_seqnr(struct ssh *ssh, u_int32_t *seqnr_p) { struct session_state *state = ssh->state; u_int reason, seqnr; u_char type; char *msg; for (;;) { if (compat20) { type = ssh_packet_read_poll2(ssh, seqnr_p); if (type) { 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: ssh_packet_get_char(ssh); msg = ssh_packet_get_string(ssh, NULL); debug("Remote: %.900s", msg); xfree(msg); msg = ssh_packet_get_string(ssh, NULL); xfree(msg); break; case SSH2_MSG_DISCONNECT: reason = ssh_packet_get_int(ssh); msg = ssh_packet_get_string(ssh, NULL); logit("Received disconnect from %s: %u: %.400s", get_remote_ipaddr(), reason, msg); xfree(msg); cleanup_exit(255); break; case SSH2_MSG_UNIMPLEMENTED: seqnr = ssh_packet_get_int(ssh); debug("Received SSH2_MSG_UNIMPLEMENTED for %u", seqnr); break; default: return type; } } else { type = ssh_packet_read_poll1(ssh); switch (type) { case SSH_MSG_IGNORE: break; case SSH_MSG_DEBUG: msg = ssh_packet_get_string(ssh, NULL); debug("Remote: %.900s", msg); xfree(msg); break; case SSH_MSG_DISCONNECT: msg = ssh_packet_get_string(ssh, NULL); logit("Received disconnect from %s: %.400s", get_remote_ipaddr(), msg); cleanup_exit(255); break; default: if (type) DBG(debug("received packet type %d", type)); return type; } } } } int ssh_packet_read_poll(struct ssh *ssh) { return ssh_packet_read_poll_seqnr(ssh, NULL); } /* * Buffers the given amount of input characters. This is intended to be used * together with packet_read_poll. */ void ssh_packet_process_incoming(struct ssh *ssh, const char *buf, u_int len) { struct session_state *state = ssh->state; if (state->packet_discard) { state->keep_alive_timeouts = 0; /* ?? */ if (len >= state->packet_discard) ssh_packet_stop_discard(ssh); state->packet_discard -= len; return; } buffer_append(&ssh->state->input, buf, len); } /* Returns a character from the packet. */ u_int ssh_packet_get_char(struct ssh *ssh) { char ch; buffer_get(&ssh->state->incoming_packet, &ch, 1); return (u_char) ch; } /* Returns an integer from the packet data. */ u_int ssh_packet_get_int(struct ssh *ssh) { return buffer_get_int(&ssh->state->incoming_packet); } /* Returns an 64 bit integer from the packet data. */ u_int64_t ssh_packet_get_int64(struct ssh *ssh) { return buffer_get_int64(&ssh->state->incoming_packet); } /* * Returns an arbitrary precision integer from the packet data. The integer * must have been initialized before this call. */ void ssh_packet_get_bignum(struct ssh *ssh, BIGNUM * value) { buffer_get_bignum(&ssh->state->incoming_packet, value); } void ssh_packet_get_bignum2(struct ssh *ssh, BIGNUM * value) { buffer_get_bignum2(&ssh->state->incoming_packet, value); } void ssh_packet_get_ecpoint(struct ssh *ssh, const EC_GROUP *curve, EC_POINT *point) { buffer_get_ecpoint(&ssh->state->incoming_packet, curve, point); } void * ssh_packet_get_raw(struct ssh *ssh, u_int *length_ptr) { u_int bytes = buffer_len(&ssh->state->incoming_packet); if (length_ptr != NULL) *length_ptr = bytes; return buffer_ptr(&ssh->state->incoming_packet); } int ssh_packet_remaining(struct ssh *ssh) { return buffer_len(&ssh->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 * ssh_packet_get_string(struct ssh *ssh, u_int *length_ptr) { return buffer_get_string(&ssh->state->incoming_packet, length_ptr); } const void * ssh_packet_get_string_ptr(struct ssh *ssh, u_int *length_ptr) { return buffer_get_string_ptr(&ssh->state->incoming_packet, length_ptr); } /* Ensures the returned string has no embedded \0 characters in it. */ char * ssh_packet_get_cstring(struct ssh *ssh, u_int *length_ptr) { return buffer_get_cstring(&ssh->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 ssh_packet_send_debug(struct ssh *ssh, const char *fmt,...) { char buf[1024]; va_list args; if (compat20 && (ssh->datafellows & SSH_BUG_DEBUG)) return; va_start(args, fmt); vsnprintf(buf, sizeof(buf), fmt, args); va_end(args); if (compat20) { ssh_packet_start(ssh, SSH2_MSG_DEBUG); ssh_packet_put_char(ssh, 0); /* bool: always display */ ssh_packet_put_cstring(ssh, buf); ssh_packet_put_cstring(ssh, ""); } else { ssh_packet_start(ssh, SSH_MSG_DEBUG); ssh_packet_put_cstring(ssh, buf); } ssh_packet_send(ssh); ssh_packet_write_wait(ssh); } /* * 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 ssh_packet_disconnect(struct ssh *ssh, 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) { ssh_packet_start(ssh, SSH2_MSG_DISCONNECT); ssh_packet_put_int(ssh, SSH2_DISCONNECT_PROTOCOL_ERROR); ssh_packet_put_cstring(ssh, buf); ssh_packet_put_cstring(ssh, ""); } else { ssh_packet_start(ssh, SSH_MSG_DISCONNECT); ssh_packet_put_cstring(ssh, buf); } ssh_packet_send(ssh); ssh_packet_write_wait(ssh); /* Stop listening for connections. */ channel_close_all(); /* Close the connection. */ ssh_packet_close(ssh); cleanup_exit(255); } /* Checks if there is any buffered output, and tries to write some of the output. */ void ssh_packet_write_poll(struct ssh *ssh) { struct session_state *state = ssh->state; int len = buffer_len(&state->output); int cont; if (len > 0) { cont = 0; len = roaming_write(state->connection_out, buffer_ptr(&state->output), len, &cont); if (len == -1) { if (errno == EINTR || errno == EAGAIN) return; fatal("Write failed: %.100s", strerror(errno)); } if (len == 0 && !cont) fatal("Write connection closed"); buffer_consume(&state->output, len); } } /* * Calls packet_write_poll repeatedly until all pending output data has been * written. */ void ssh_packet_write_wait(struct ssh *ssh) { fd_set *setp; int ret, ms_remain; struct timeval start, timeout, *timeoutp = NULL; struct session_state *state = ssh->state; setp = (fd_set *)xcalloc(howmany(state->connection_out + 1, NFDBITS), sizeof(fd_mask)); ssh_packet_write_poll(ssh); while (ssh_packet_have_data_to_write(ssh)) { memset(setp, 0, howmany(state->connection_out + 1, NFDBITS) * sizeof(fd_mask)); FD_SET(state->connection_out, setp); if (state->packet_timeout_ms > 0) { ms_remain = state->packet_timeout_ms; timeoutp = &timeout; } for (;;) { if (state->packet_timeout_ms != -1) { ms_to_timeval(&timeout, ms_remain); gettimeofday(&start, NULL); } if ((ret = select(state->connection_out + 1, NULL, setp, NULL, timeoutp)) >= 0) break; if (errno != EAGAIN && errno != EINTR) break; if (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); } ssh_packet_write_poll(ssh); } xfree(setp); } /* Returns true if there is buffered data to write to the connection. */ int ssh_packet_have_data_to_write(struct ssh *ssh) { return buffer_len(&ssh->state->output) != 0; } /* Returns true if there is not too much data to write to the connection. */ int ssh_packet_not_very_much_data_to_write(struct ssh *ssh) { if (ssh->state->interactive_mode) return buffer_len(&ssh->state->output) < 16384; else return buffer_len(&ssh->state->output) < 128 * 1024; } void ssh_packet_set_tos(struct ssh *ssh, int tos) { if (!ssh_packet_connection_is_on_socket(ssh)) return; switch (ssh_packet_connection_af(ssh)) { case AF_INET: debug3("%s: set IP_TOS 0x%02x", __func__, tos); if (setsockopt(ssh->state->connection_in, IPPROTO_IP, IP_TOS, &tos, sizeof(tos)) < 0) error("setsockopt IP_TOS %d: %.100s:", tos, strerror(errno)); break; case AF_INET6: debug3("%s: set IPV6_TCLASS 0x%02x", __func__, tos); if (setsockopt(ssh->state->connection_in, IPPROTO_IPV6, IPV6_TCLASS, &tos, sizeof(tos)) < 0) error("setsockopt IPV6_TCLASS %d: %.100s:", tos, strerror(errno)); break; } } /* Informs that the current session is interactive. Sets IP flags for that. */ void ssh_packet_set_interactive(struct ssh *ssh, int interactive, int qos_interactive, int qos_bulk) { struct session_state *state = ssh->state; if (state->set_interactive_called) return; state->set_interactive_called = 1; /* Record that we are in interactive mode. */ state->interactive_mode = interactive; /* Only set socket options if using a socket. */ if (!ssh_packet_connection_is_on_socket(ssh)) return; set_nodelay(state->connection_in); ssh_packet_set_tos(ssh, interactive ? qos_interactive : qos_bulk); } /* Returns true if the current connection is interactive. */ int ssh_packet_is_interactive(struct ssh *ssh) { return ssh->state->interactive_mode; } int ssh_packet_set_maxsize(struct ssh *ssh, u_int s) { struct session_state *state = ssh->state; if (state->set_maxsize_called) { logit("packet_set_maxsize: called twice: old %d new %d", state->max_packet_size, s); return -1; } if (s < 4 * 1024 || s > 1024 * 1024) { logit("packet_set_maxsize: bad size %d", s); return -1; } state->set_maxsize_called = 1; debug("packet_set_maxsize: setting to %d", s); state->max_packet_size = s; return s; } int ssh_packet_inc_alive_timeouts(struct ssh *ssh) { return ++ssh->state->keep_alive_timeouts; } void ssh_packet_set_alive_timeouts(struct ssh *ssh, int ka) { ssh->state->keep_alive_timeouts = ka; } u_int ssh_packet_get_maxsize(struct ssh *ssh) { return ssh->state->max_packet_size; } /* roundup current message to pad bytes */ void ssh_packet_add_padding(struct ssh *ssh, u_char pad) { ssh->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 ssh_packet_send_ignore(struct ssh *ssh, int nbytes) { u_int32_t rnd = 0; int i; ssh_packet_start(ssh, compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE); ssh_packet_put_int(ssh, nbytes); for (i = 0; i < nbytes; i++) { if (i % 4 == 0) rnd = arc4random(); ssh_packet_put_char(ssh, (u_char)rnd & 0xff); rnd >>= 8; } } #define MAX_PACKETS (1U<<31) int ssh_packet_need_rekeying(struct ssh *ssh) { struct session_state *state = ssh->state; if (ssh->datafellows & SSH_BUG_NOREKEY) return 0; return (state->p_send.packets > MAX_PACKETS) || (state->p_read.packets > MAX_PACKETS) || (state->max_blocks_out && (state->p_send.blocks > state->max_blocks_out)) || (state->max_blocks_in && (state->p_read.blocks > state->max_blocks_in)); } void ssh_packet_set_rekey_limit(struct ssh *ssh, u_int32_t bytes) { ssh->state->rekey_limit = bytes; } void ssh_packet_set_server(struct ssh *ssh) { ssh->state->server_side = 1; } void ssh_packet_set_authenticated(struct ssh *ssh) { ssh->state->after_authentication = 1; } void * ssh_packet_get_input(struct ssh *ssh) { return (void *)&ssh->state->input; } void * ssh_packet_get_output(struct ssh *ssh) { return (void *)&ssh->state->output; } void * ssh_packet_get_newkeys(struct ssh *ssh, int mode) { return (void *)ssh->state->newkeys[mode]; } /* TODO Hier brauchen wir noch eine Loesung! */ /* * Save the state for the real connection, and use a separate state when * resuming a suspended connection. */ void ssh_packet_backup_state(struct ssh *ssh, struct ssh *backup_state) { struct ssh *tmp; close(ssh->state->connection_in); ssh->state->connection_in = -1; close(ssh->state->connection_out); ssh->state->connection_out = -1; if (backup_state) tmp = backup_state; else tmp = ssh_alloc_session_state(); backup_state = ssh; ssh = tmp; } /* TODO Hier brauchen wir noch eine Loesung! */ /* * Swap in the old state when resuming a connecion. */ void ssh_packet_restore_state(struct ssh *ssh, struct ssh *backup_state) { struct ssh *tmp; void *buf; u_int len; tmp = backup_state; backup_state = ssh; ssh = tmp; ssh->state->connection_in = backup_state->state->connection_in; backup_state->state->connection_in = -1; ssh->state->connection_out = backup_state->state->connection_out; backup_state->state->connection_out = -1; len = buffer_len(&backup_state->state->input); if (len > 0) { buf = buffer_ptr(&backup_state->state->input); buffer_append(&ssh->state->input, buf, len); buffer_clear(&backup_state->state->input); add_recv_bytes(len); } }