/*
- *
- * packet.c
- *
* Author: Tatu Ylonen <ylo@cs.hut.fi>
- *
* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
* All rights reserved
- *
- * Created: Sat Mar 18 02:40:40 1995 ylo
- *
* 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 Markus Friedl. All rights reserved.
*
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "includes.h"
-RCSID("$Id$");
+RCSID("$OpenBSD: packet.c,v 1.55 2001/03/01 02:45:10 deraadt Exp $");
#include "xmalloc.h"
#include "buffer.h"
#include "packet.h"
#include "bufaux.h"
-#include "ssh.h"
#include "crc32.h"
-#include "cipher.h"
#include "getput.h"
#include "compress.h"
#include "channels.h"
#include "compat.h"
+#include "ssh1.h"
#include "ssh2.h"
-#include <openssl/bn.h>
-#include <openssl/dh.h>
-#include <openssl/hmac.h>
-#include "buffer.h"
+#include "cipher.h"
#include "kex.h"
-#include "hmac.h"
+#include "mac.h"
+#include "log.h"
+#include "canohost.h"
#ifdef PACKET_DEBUG
#define DBG(x) x
static int cipher_type = SSH_CIPHER_NONE;
/* Protocol flags for the remote side. */
-static unsigned int remote_protocol_flags = 0;
+static u_int remote_protocol_flags = 0;
/* Encryption context for receiving data. This is only used for decryption. */
static CipherContext receive_context;
void
packet_set_connection(int fd_in, int fd_out)
{
+ Cipher *none = cipher_by_name("none");
+ if (none == NULL)
+ fatal("packet_set_connection: cannot load cipher 'none'");
connection_in = fd_in;
connection_out = fd_out;
cipher_type = SSH_CIPHER_NONE;
- cipher_set_key(&send_context, SSH_CIPHER_NONE, (unsigned char *) "", 0);
- cipher_set_key(&receive_context, SSH_CIPHER_NONE, (unsigned char *) "", 0);
+ cipher_init(&send_context, none, (u_char *) "", 0, NULL, 0);
+ cipher_init(&receive_context, none, (u_char *) "", 0, NULL, 0);
if (!initialized) {
initialized = 1;
buffer_init(&input);
/* Sets remote side protocol flags. */
void
-packet_set_protocol_flags(unsigned int protocol_flags)
+packet_set_protocol_flags(u_int protocol_flags)
{
remote_protocol_flags = protocol_flags;
channel_set_options((protocol_flags & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) != 0);
/* Returns the remote protocol flags set earlier by the above function. */
-unsigned int
+u_int
packet_get_protocol_flags()
{
return remote_protocol_flags;
void
packet_encrypt(CipherContext * cc, void *dest, void *src,
- unsigned int bytes)
+ u_int bytes)
{
cipher_encrypt(cc, dest, src, bytes);
}
*/
void
-packet_decrypt(CipherContext * cc, void *dest, void *src,
- unsigned int bytes)
+packet_decrypt(CipherContext *context, void *dest, void *src, u_int bytes)
{
- int i;
-
- if ((bytes % 8) != 0)
- fatal("packet_decrypt: bad ciphertext length %d", bytes);
-
/*
* Cryptographic attack detector for ssh - Modifications for packet.c
* (C)1998 CORE-SDI, Buenos Aires Argentina Ariel Futoransky(futo@core-sdi.com)
*/
-
- if (cc->type == SSH_CIPHER_NONE || compat20) {
- i = DEATTACK_OK;
- } else {
- i = detect_attack(src, bytes, NULL);
- }
- if (i == DEATTACK_DETECTED)
+ if (!compat20 &&
+ context->cipher->number != SSH_CIPHER_NONE &&
+ detect_attack(src, bytes, NULL) == DEATTACK_DETECTED)
packet_disconnect("crc32 compensation attack: network attack detected");
- cipher_decrypt(cc, dest, src, bytes);
+ cipher_decrypt(context, dest, src, bytes);
}
/*
*/
void
-packet_set_encryption_key(const unsigned char *key, unsigned int keylen,
- int cipher)
+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("keylen too small: %d", keylen);
-
- /* All other ciphers use the same key in both directions for now. */
- cipher_set_key(&receive_context, cipher, key, keylen);
- cipher_set_key(&send_context, cipher, key, keylen);
+ fatal("packet_set_encryption_key: keylen too small: %d", keylen);
+ cipher_init(&receive_context, cipher, key, keylen, NULL, 0);
+ cipher_init(&send_context, cipher, key, keylen, NULL, 0);
}
/* Starts constructing a packet to send. */
void
packet_start(int type)
{
- DBG(debug("packet_start[%d]",type));
+ DBG(debug("packet_start[%d]", type));
if (use_ssh2_packet_format)
packet_start2(type);
else
/* Appends an integer to the packet data. */
void
-packet_put_int(unsigned int value)
+packet_put_int(u_int value)
{
buffer_put_int(&outgoing_packet, value);
}
/* Appends a string to packet data. */
void
-packet_put_string(const char *buf, unsigned int len)
+packet_put_string(const char *buf, u_int len)
{
buffer_put_string(&outgoing_packet, buf, len);
}
}
void
-packet_put_raw(const char *buf, unsigned int len)
+packet_put_raw(const char *buf, u_int len)
{
buffer_append(&outgoing_packet, buf, len);
}
*/
void
-packet_send1()
+packet_send1(void)
{
char buf[8], *cp;
int i, padding, len;
- unsigned int checksum;
+ u_int checksum;
u_int32_t rand = 0;
/*
buffer_consume(&outgoing_packet, 8 - padding);
/* Add check bytes. */
- checksum = crc32((unsigned char *) buffer_ptr(&outgoing_packet),
- buffer_len(&outgoing_packet));
+ checksum = ssh_crc32((u_char *) buffer_ptr(&outgoing_packet),
+ buffer_len(&outgoing_packet));
PUT_32BIT(buf, checksum);
buffer_append(&outgoing_packet, buf, 4);
* Finalize packet in SSH2 format (compress, mac, encrypt, enqueue)
*/
void
-packet_send2()
+packet_send2(void)
{
- unsigned char *macbuf = NULL;
+ static u_int32_t seqnr = 0;
+ u_char *macbuf = NULL;
char *cp;
- unsigned int packet_length = 0;
- unsigned int i, padlen, len;
+ u_int packet_length = 0;
+ u_int i, padlen, len;
u_int32_t rand = 0;
- static unsigned int seqnr = 0;
int type;
Enc *enc = NULL;
Mac *mac = NULL;
mac = &kex->mac[MODE_OUT];
comp = &kex->comp[MODE_OUT];
}
- block_size = enc ? enc->block_size : 8;
+ block_size = enc ? enc->cipher->block_size : 8;
cp = buffer_ptr(&outgoing_packet);
type = cp[5] & 0xff;
if (padlen < 4)
padlen += block_size;
buffer_append_space(&outgoing_packet, &cp, padlen);
- if (enc && enc->type != SSH_CIPHER_NONE) {
+ if (enc && enc->cipher->number != SSH_CIPHER_NONE) {
/* random padding */
for (i = 0; i < padlen; i++) {
if (i % 4 == 0)
rand = arc4random();
cp[i] = rand & 0xff;
- rand <<= 8;
+ rand >>= 8;
}
} else {
/* clear padding */
/* compute MAC over seqnr and packet(length fields, payload, padding) */
if (mac && mac->enabled) {
- macbuf = hmac( mac->md, seqnr,
- (unsigned char *) buffer_ptr(&outgoing_packet),
- buffer_len(&outgoing_packet),
- mac->key, mac->key_len
- );
- DBG(debug("done calc HMAC out #%d", seqnr));
+ macbuf = mac_compute(mac, seqnr,
+ (u_char *) buffer_ptr(&outgoing_packet),
+ buffer_len(&outgoing_packet));
+ DBG(debug("done calc MAC out #%d", seqnr));
}
/* encrypt packet and append to output buffer. */
buffer_append_space(&output, &cp, buffer_len(&outgoing_packet));
fatal("packet_send2: no KEX");
if (mac->md != NULL)
mac->enabled = 1;
- DBG(debug("cipher_set_key_iv send_context"));
- cipher_set_key_iv(&send_context, enc->type,
- enc->key, enc->key_len,
- enc->iv, enc->iv_len);
+ DBG(debug("cipher_init send_context"));
+ cipher_init(&send_context, enc->cipher,
+ enc->key, enc->cipher->key_len,
+ enc->iv, enc->cipher->block_size);
clear_enc_keys(enc, kex->we_need);
if (comp->type != 0 && comp->enabled == 0) {
comp->enabled = 1;
FD_SET(connection_in, &set);
/* Wait for some data to arrive. */
- select(connection_in + 1, &set, NULL, NULL, NULL);
+ while (select(connection_in + 1, &set, NULL, NULL, NULL) == -1 &&
+ (errno == EAGAIN || errno == EINTR))
+ ;
/* Read data from the socket. */
len = read(connection_in, buf, sizeof(buf));
int
packet_read_poll1(int *payload_len_ptr)
{
- unsigned int len, padded_len;
- unsigned char *ucp;
+ u_int len, padded_len;
+ u_char *ucp;
char buf[8], *cp;
- unsigned int checksum, stored_checksum;
+ u_int checksum, stored_checksum;
/* Check if input size is less than minimum packet size. */
if (buffer_len(&input) < 4 + 8)
return SSH_MSG_NONE;
/* Get length of incoming packet. */
- ucp = (unsigned char *) buffer_ptr(&input);
+ ucp = (u_char *) buffer_ptr(&input);
len = GET_32BIT(ucp);
if (len < 1 + 2 + 2 || len > 256 * 1024)
packet_disconnect("Bad packet length %d.", len);
#endif
/* Compute packet checksum. */
- checksum = crc32((unsigned char *) buffer_ptr(&incoming_packet),
+ checksum = ssh_crc32((u_char *) buffer_ptr(&incoming_packet),
buffer_len(&incoming_packet) - 4);
/* Skip padding. */
packet_disconnect("packet_read_poll: len %d != buffer_len %d.",
len, buffer_len(&incoming_packet));
- ucp = (unsigned char *) buffer_ptr(&incoming_packet) + len - 4;
+ ucp = (u_char *) buffer_ptr(&incoming_packet) + len - 4;
stored_checksum = GET_32BIT(ucp);
if (checksum != stored_checksum)
packet_disconnect("Corrupted check bytes on input.");
*payload_len_ptr = buffer_len(&incoming_packet);
/* Return type. */
- return (unsigned char) buf[0];
+ return (u_char) buf[0];
}
int
packet_read_poll2(int *payload_len_ptr)
{
- unsigned int padlen, need;
- unsigned char buf[8], *macbuf;
- unsigned char *ucp;
+ static u_int32_t seqnr = 0;
+ static u_int packet_length = 0;
+ u_int padlen, need;
+ u_char buf[8], *macbuf;
+ u_char *ucp;
char *cp;
- static unsigned int packet_length = 0;
- static unsigned int seqnr = 0;
int type;
int maclen, block_size;
Enc *enc = NULL;
comp = &kex->comp[MODE_IN];
}
maclen = mac && mac->enabled ? mac->mac_len : 0;
- block_size = enc ? enc->block_size : 8;
+ block_size = enc ? enc->cipher->block_size : 8;
if (packet_length == 0) {
/*
buffer_append_space(&incoming_packet, &cp, block_size);
packet_decrypt(&receive_context, cp, buffer_ptr(&input),
block_size);
- ucp = (unsigned char *) buffer_ptr(&incoming_packet);
+ ucp = (u_char *) buffer_ptr(&incoming_packet);
packet_length = GET_32BIT(ucp);
if (packet_length < 1 + 4 || packet_length > 256 * 1024) {
buffer_dump(&incoming_packet);
* increment sequence number for incoming packet
*/
if (mac && mac->enabled) {
- macbuf = hmac( mac->md, seqnr,
- (unsigned char *) buffer_ptr(&incoming_packet),
- buffer_len(&incoming_packet),
- mac->key, mac->key_len
- );
+ macbuf = mac_compute(mac, seqnr,
+ (u_char *) buffer_ptr(&incoming_packet),
+ buffer_len(&incoming_packet));
if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0)
- packet_disconnect("Corrupted HMAC on input.");
- DBG(debug("HMAC #%d ok", seqnr));
+ packet_disconnect("Corrupted MAC on input.");
+ DBG(debug("MAC #%d ok", seqnr));
buffer_consume(&input, mac->mac_len);
}
if (++seqnr == 0)
packet_length = 0;
/* extract packet type */
- type = (unsigned char)buf[0];
+ type = (u_char)buf[0];
if (type == SSH2_MSG_NEWKEYS) {
if (kex==NULL || mac==NULL || enc==NULL || comp==NULL)
fatal("packet_read_poll2: no KEX");
if (mac->md != NULL)
mac->enabled = 1;
- DBG(debug("cipher_set_key_iv receive_context"));
- cipher_set_key_iv(&receive_context, enc->type,
- enc->key, enc->key_len,
- enc->iv, enc->iv_len);
+ DBG(debug("cipher_init receive_context"));
+ cipher_init(&receive_context, enc->cipher,
+ enc->key, enc->cipher->key_len,
+ enc->iv, enc->cipher->block_size);
clear_enc_keys(enc, kex->we_need);
if (comp->type != 0 && comp->enabled == 0) {
comp->enabled = 1;
}
#ifdef PACKET_DEBUG
- fprintf(stderr, "read/plain[%d]:\r\n",type);
+ fprintf(stderr, "read/plain[%d]:\r\n", type);
buffer_dump(&incoming_packet);
#endif
- return (unsigned char)type;
+ return (u_char)type;
}
int
case SSH2_MSG_DISCONNECT:
reason = packet_get_int();
msg = packet_get_string(NULL);
- log("Received disconnect: %d: %.900s", reason, msg);
+ log("Received disconnect from %s: %d: %.400s", get_remote_ipaddr(),
+ reason, msg);
xfree(msg);
fatal_cleanup();
break;
default:
return type;
break;
- }
+ }
} else {
switch(type) {
case SSH_MSG_IGNORE:
break;
case SSH_MSG_DISCONNECT:
msg = packet_get_string(NULL);
- log("Received disconnect: %.900s", msg);
+ log("Received disconnect from %s: %.400s", get_remote_ipaddr(),
+ msg);
fatal_cleanup();
xfree(msg);
break;
DBG(debug("received packet type %d", type));
return type;
break;
- }
+ }
}
}
}
*/
void
-packet_process_incoming(const char *buf, unsigned int len)
+packet_process_incoming(const char *buf, u_int len)
{
buffer_append(&input, buf, len);
}
/* Returns a character from the packet. */
-unsigned int
+u_int
packet_get_char()
{
char ch;
buffer_get(&incoming_packet, &ch, 1);
- return (unsigned char) ch;
+ return (u_char) ch;
}
/* Returns an integer from the packet data. */
-unsigned int
+u_int
packet_get_int()
{
return buffer_get_int(&incoming_packet);
*/
char *
-packet_get_string(unsigned int *length_ptr)
+packet_get_string(u_int *length_ptr)
{
return buffer_get_string(&incoming_packet, length_ptr);
}
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);
packet_write_poll();
while (packet_have_data_to_write()) {
fd_set set;
+
FD_ZERO(&set);
FD_SET(connection_out, &set);
- select(connection_out + 1, NULL, &set, NULL, NULL);
+ while (select(connection_out + 1, NULL, &set, NULL, NULL) == -1 &&
+ (errno == EAGAIN || errno == EINTR))
+ ;
packet_write_poll();
}
}
/* Informs that the current session is interactive. Sets IP flags for that. */
void
-packet_set_interactive(int interactive, int keepalives)
+packet_set_interactive(int interactive)
{
+ static int called = 0;
+#if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN)
+ int lowdelay = IPTOS_LOWDELAY;
+ int throughput = IPTOS_THROUGHPUT;
+#endif
int on = 1;
+ if (called)
+ return;
+ called = 1;
+
/* Record that we are in interactive mode. */
interactive_mode = interactive;
/* Only set socket options if using a socket. */
if (!packet_connection_is_on_socket())
return;
- if (keepalives) {
- /* Set keepalives if requested. */
- if (setsockopt(connection_in, SOL_SOCKET, SO_KEEPALIVE, (void *) &on,
- sizeof(on)) < 0)
- error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno));
- }
/*
- * IPTOS_LOWDELAY, TCP_NODELAY and IPTOS_THROUGHPUT are IPv4 only
+ * IPTOS_LOWDELAY and IPTOS_THROUGHPUT are IPv4 only
*/
- if (!packet_connection_is_ipv4())
- return;
if (interactive) {
/*
* Set IP options for an interactive connection. Use
* IPTOS_LOWDELAY and TCP_NODELAY.
*/
- int lowdelay = IPTOS_LOWDELAY;
- if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &lowdelay,
- sizeof(lowdelay)) < 0)
- error("setsockopt IPTOS_LOWDELAY: %.100s", strerror(errno));
+#if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN)
+ if (packet_connection_is_ipv4()) {
+ if (setsockopt(connection_in, IPPROTO_IP, IP_TOS,
+ (void *) &lowdelay, sizeof(lowdelay)) < 0)
+ error("setsockopt IPTOS_LOWDELAY: %.100s",
+ strerror(errno));
+ }
+#endif
if (setsockopt(connection_in, IPPROTO_TCP, TCP_NODELAY, (void *) &on,
sizeof(on)) < 0)
error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
- } else {
+ } else if (packet_connection_is_ipv4()) {
/*
* Set IP options for a non-interactive connection. Use
* IPTOS_THROUGHPUT.
*/
- int throughput = IPTOS_THROUGHPUT;
+#if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN)
if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &throughput,
sizeof(throughput)) < 0)
error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno));
+#endif
}
}
max_packet_size = s;
return s;
}
+
+/*
+ * 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.
+ */
+/* size of current + ignore message should be n*sumlen bytes (w/o mac) */
+void
+packet_inject_ignore(int sumlen)
+{
+ int blocksize, padlen, have, need, nb, mini, nbytes;
+ Enc *enc = NULL;
+
+ if (use_ssh2_packet_format == 0)
+ return;
+
+ have = buffer_len(&outgoing_packet);
+ debug2("packet_inject_ignore: current %d", have);
+ if (kex != NULL)
+ enc = &kex->enc[MODE_OUT];
+ blocksize = enc ? enc->cipher->block_size : 8;
+ padlen = blocksize - (have % blocksize);
+ if (padlen < 4)
+ padlen += blocksize;
+ have += padlen;
+ have /= blocksize; /* # of blocks for current message */
+
+ nb = roundup(sumlen, blocksize) / blocksize; /* blocks for both */
+ mini = roundup(5+1+4+4, blocksize) / blocksize; /* minsize ignore msg */
+ need = nb - (have % nb); /* blocks for ignore */
+ if (need <= mini)
+ need += nb;
+ nbytes = (need - mini) * blocksize; /* size of ignore payload */
+ debug2("packet_inject_ignore: block %d have %d nb %d mini %d need %d",
+ blocksize, have, nb, mini, need);
+
+ /* enqueue current message and append a ignore message */
+ packet_send();
+ packet_send_ignore(nbytes);
+}
+
+void
+packet_send_ignore(int nbytes)
+{
+ u_int32_t rand = 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)
+ rand = arc4random();
+ packet_put_char(rand & 0xff);
+ rand >>= 8;
+ }
+}
andersk / openssh.git / blobdiff