File: [local] / src / usr.bin / ssh / packet.c (download)
Revision 1.170, Tue Aug 31 11:54:45 2010 UTC (13 years, 9 months ago) by djm
Branch: MAIN
Changes since 1.169: +13 -1 lines
Implement Elliptic Curve Cryptography modes for key exchange (ECDH) and
host/user keys (ECDSA) as specified by RFC5656. ECDH and ECDSA offer
better performance than plain DH and DSA at the same equivalent symmetric
key length, as well as much shorter keys.
Only the mandatory sections of RFC5656 are implemented, specifically the
three REQUIRED curves nistp256, nistp384 and nistp521 and only ECDH and
ECDSA. Point compression (optional in RFC5656 is NOT implemented).
Certificate host and user keys using the new ECDSA key types are supported.
Note that this code has not been tested for interoperability and may be
subject to change.
feedback and ok markus@
|
/* $OpenBSD: packet.c,v 1.170 2010/08/31 11:54:45 djm Exp $ */
/*
* Author: Tatu Ylonen <ylo@cs.hut.fi>
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
* This file contains code implementing the packet protocol and communication
* with the other side. This same code is used both on client and server side.
*
* As far as I am concerned, the code I have written for this software
* can be used freely for any purpose. Any derived versions of this
* software must be clearly marked as such, and if the derived work is
* incompatible with the protocol description in the RFC file, it must be
* called by a name other than "ssh" or "Secure Shell".
*
*
* SSH2 packet format added by Markus Friedl.
* Copyright (c) 2000, 2001 Markus Friedl. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/types.h>
#include <sys/queue.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/param.h>
#include <netinet/in_systm.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <errno.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <signal.h>
#include "xmalloc.h"
#include "buffer.h"
#include "packet.h"
#include "crc32.h"
#include "compress.h"
#include "deattack.h"
#include "channels.h"
#include "compat.h"
#include "ssh1.h"
#include "ssh2.h"
#include "cipher.h"
#include "key.h"
#include "kex.h"
#include "mac.h"
#include "log.h"
#include "canohost.h"
#include "misc.h"
#include "ssh.h"
#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;
};
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)
{
Cipher *none = cipher_by_name("none");
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;
cipher_init(&active_state->send_context, none, (const u_char *)"",
0, NULL, 0, CIPHER_ENCRYPT);
cipher_init(&active_state->receive_context, none, (const u_char *)"",
0, NULL, 0, CIPHER_DECRYPT);
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);
}
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))
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;
if (mode == MODE_OUT)
cc = &active_state->send_context;
else
cc = &active_state->receive_context;
cipher_get_keyiv(cc, iv, len);
}
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;
if (mode == MODE_OUT)
cc = &active_state->send_context;
else
cc = &active_state->receive_context;
cipher_set_keyiv(cc, dat);
}
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;
}
/* returns 1 if connection is via ipv4 */
int
packet_connection_is_ipv4(void)
{
struct sockaddr_storage to;
socklen_t tolen = sizeof(to);
memset(&to, 0, sizeof(to));
if (getsockname(active_state->connection_out, (struct sockaddr *)&to,
&tolen) < 0)
return 0;
if (to.ss_family != AF_INET)
return 0;
return 1;
}
/* 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)
{
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(active_state->ssh1_key, key, keylen);
active_state->ssh1_keylen = keylen;
cipher_init(&active_state->send_context, cipher, key, keylen, NULL,
0, CIPHER_ENCRYPT);
cipher_init(&active_state->receive_context, cipher, key, keylen, NULL,
0, CIPHER_DECRYPT);
}
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);
}
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);
}
void
packet_put_ecpoint(const EC_GROUP *curve, const EC_POINT *point)
{
buffer_put_ecpoint(&active_state->outgoing_packet, curve, point);
}
/*
* 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));
cipher_crypt(&active_state->send_context, cp,
buffer_ptr(&active_state->outgoing_packet),
buffer_len(&active_state->outgoing_packet));
#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 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);
xfree(enc->name);
xfree(enc->iv);
xfree(enc->key);
xfree(mac->name);
xfree(mac->key);
xfree(comp->name);
xfree(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 (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 &&
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 = 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 (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;
}
block_size = enc ? enc->block_size : 8;
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
*/
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);
debug3("packet_send2: adding %d (len %d padlen %d extra_pad %d)",
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 */
memset(cp, 0, padlen);
}
/* packet_length includes payload, padding and padding length field */
packet_length = buffer_len(&active_state->outgoing_packet) - 4;
cp = buffer_ptr(&active_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, active_state->p_send.seqnr,
buffer_ptr(&active_state->outgoing_packet),
buffer_len(&active_state->outgoing_packet));
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,
buffer_len(&active_state->outgoing_packet));
cipher_crypt(&active_state->send_context, cp,
buffer_ptr(&active_state->outgoing_packet),
buffer_len(&active_state->outgoing_packet));
/* append unencrypted MAC */
if (mac && mac->enabled)
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 += (packet_length + 4) / block_size;
active_state->p_send.bytes += packet_length + 4;
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))) {
debug("enqueue packet: %u", type);
p = xmalloc(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;
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);
xfree(p);
packet_send2_wrapped();
}
}
}
void
packet_send(void)
{
if (compat20)
packet_send2();
else
packet_send1();
DBG(debug("packet_send done"));
}
/*
* Waits until a packet has been received, and returns its type. Note that
* no other data is processed until this returns, so this function should not
* be used during the interactive session.
*/
int
packet_read_seqnr(u_int32_t *seqnr_p)
{
int type, len, 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(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) {
xfree(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)
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);
cipher_crypt(&active_state->receive_context, cp,
buffer_ptr(&active_state->input), padded_len);
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 *macbuf, *cp, type;
u_int maclen, block_size;
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;
}
maclen = mac && mac->enabled ? mac->mac_len : 0;
block_size = enc ? enc->block_size : 8;
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);
cipher_crypt(&active_state->receive_context, cp,
buffer_ptr(&active_state->input), block_size);
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;
}
DBG(debug("input: packet len %u", active_state->packlen+4));
buffer_consume(&active_state->input, block_size);
}
/* we have a partial packet of block_size bytes */
need = 4 + active_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);
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
*/
if (buffer_len(&active_state->input) < need + maclen)
return SSH_MSG_NONE;
#ifdef PACKET_DEBUG
fprintf(stderr, "read_poll enc/full: ");
buffer_dump(&active_state->input);
#endif
cp = buffer_append_space(&active_state->incoming_packet, need);
cipher_crypt(&active_state->receive_context, cp,
buffer_ptr(&active_state->input), need);
buffer_consume(&active_state->input, need);
/*
* compute MAC over seqnr and packet,
* increment sequence number for incoming packet
*/
if (mac && mac->enabled) {
macbuf = mac_compute(mac, active_state->p_read.seqnr,
buffer_ptr(&active_state->incoming_packet),
buffer_len(&active_state->incoming_packet));
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);
xfree(msg);
msg = packet_get_string(NULL);
xfree(msg);
break;
case SSH2_MSG_DISCONNECT:
reason = packet_get_int();
msg = packet_get_string(NULL);
logit("Received disconnect from %s: %u: %.400s",
get_remote_ipaddr(), reason, msg);
xfree(msg);
cleanup_exit(255);
break;
case SSH2_MSG_UNIMPLEMENTED:
seqnr = packet_get_int();
debug("Received SSH2_MSG_UNIMPLEMENTED for %u",
seqnr);
break;
default:
return type;
}
} else {
type = packet_read_poll1();
switch (type) {
case SSH_MSG_IGNORE:
break;
case SSH_MSG_DEBUG:
msg = packet_get_string(NULL);
debug("Remote: %.900s", msg);
xfree(msg);
break;
case SSH_MSG_DISCONNECT:
msg = packet_get_string(NULL);
logit("Received disconnect from %s: %.400s",
get_remote_ipaddr(), msg);
cleanup_exit(255);
break;
default:
if (type)
DBG(debug("received packet type %d", type));
return type;
}
}
}
}
int
packet_read_poll(void)
{
return packet_read_poll_seqnr(NULL);
}
/*
* Buffers the given amount of input characters. This is intended to be used
* together with packet_read_poll.
*/
void
packet_process_incoming(const char *buf, u_int len)
{
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.
*/
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);
}
void
packet_get_ecpoint(const EC_GROUP *curve, EC_POINT *point)
{
buffer_get_ecpoint(&active_state->incoming_packet, curve, point);
}
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);
}
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);
}
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)
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;
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)
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();
}
xfree(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 interactive)
{
int tos = interactive ? IPTOS_LOWDELAY : IPTOS_THROUGHPUT;
if (!packet_connection_is_on_socket() ||
!packet_connection_is_ipv4())
return;
if (setsockopt(active_state->connection_in, IPPROTO_IP, IP_TOS, &tos,
sizeof(tos)) < 0)
error("setsockopt IP_TOS %d: %.100s:",
tos, strerror(errno));
}
/* Informs that the current session is interactive. Sets IP flags for that. */
void
packet_set_interactive(int interactive)
{
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);
}
/* 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));
}
void
packet_set_rekey_limit(u_int32_t bytes)
{
active_state->rekey_limit = bytes;
}
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);
}
}
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