/*
- *
- * 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, 2001 Markus Friedl. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
*
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "includes.h"
-RCSID("$Id$");
+RCSID("$OpenBSD: packet.c,v 1.87 2002/01/24 21:13:23 stevesk 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"
+#include "misc.h"
#ifdef PACKET_DEBUG
#define DBG(x) x
static int connection_in = -1;
static int connection_out = -1;
-/*
- * Cipher type. This value is only used to determine whether to pad the
- * packets with zeroes or random data.
- */
-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;
/* Scratch buffer for packet compression/decompression. */
static Buffer compression_buffer;
+static int compression_buffer_ready = 0;
/* Flag indicating whether packet compression/decompression is enabled. */
static int packet_compression = 0;
/* Set to true if the connection is interactive. */
static int interactive_mode = 0;
-/* True if SSH2 packet format is used */
-int use_ssh2_packet_format = 0;
-
/* Session key information for Encryption and MAC */
-Kex *kex = NULL;
+Newkeys *newkeys[MODE_MAX];
-void
-packet_set_kex(Kex *k)
-{
- if( k->mac[MODE_IN ].key == NULL ||
- k->enc[MODE_IN ].key == NULL ||
- k->enc[MODE_IN ].iv == NULL ||
- k->mac[MODE_OUT].key == NULL ||
- k->enc[MODE_OUT].key == NULL ||
- k->enc[MODE_OUT].iv == NULL)
- fatal("bad KEX");
- kex = k;
-}
-void
-clear_enc_keys(Enc *enc, int len)
-{
- memset(enc->iv, 0, len);
- memset(enc->key, 0, len);
- xfree(enc->iv);
- xfree(enc->key);
- enc->iv = NULL;
- enc->key = NULL;
-}
-void
-packet_set_ssh2_format(void)
-{
- debug("use_ssh2_packet_format");
- use_ssh2_packet_format = 1;
-}
+/* roundup current message to extra_pad bytes */
+static u_char extra_pad = 0;
/*
* Sets the descriptors used for communication. Disables encryption until
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, "", 0, NULL, 0);
+ cipher_init(&receive_context, none, "", 0, NULL, 0);
+ newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL;
if (!initialized) {
initialized = 1;
buffer_init(&input);
/* Returns 1 if remote host is connected via socket, 0 if not. */
int
-packet_connection_is_on_socket()
+packet_connection_is_on_socket(void)
{
struct sockaddr_storage from, to;
socklen_t fromlen, tolen;
/* returns 1 if connection is via ipv4 */
int
-packet_connection_is_ipv4()
+packet_connection_is_ipv4(void)
{
struct sockaddr_storage to;
socklen_t tolen = sizeof(to);
/* Sets the connection into non-blocking mode. */
void
-packet_set_nonblocking()
+packet_set_nonblocking(void)
{
/* Set the socket into non-blocking mode. */
if (fcntl(connection_in, F_SETFL, O_NONBLOCK) < 0)
/* Returns the socket used for reading. */
int
-packet_get_connection_in()
+packet_get_connection_in(void)
{
return connection_in;
}
/* Returns the descriptor used for writing. */
int
-packet_get_connection_out()
+packet_get_connection_out(void)
{
return connection_out;
}
/* Closes the connection and clears and frees internal data structures. */
void
-packet_close()
+packet_close(void)
{
if (!initialized)
return;
buffer_free(&output);
buffer_free(&outgoing_packet);
buffer_free(&incoming_packet);
- if (packet_compression) {
+ if (compression_buffer_ready) {
buffer_free(&compression_buffer);
buffer_compress_uninit();
}
/* 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
-packet_get_protocol_flags()
+u_int
+packet_get_protocol_flags(void)
{
return remote_protocol_flags;
}
* Level is compression level 1 (fastest) - 9 (slow, best) as in gzip.
*/
-/*** XXXXX todo: kex means re-init */
-void
-packet_start_compression(int level)
+static void
+packet_init_compression(void)
{
- if (packet_compression)
- fatal("Compression already enabled.");
- packet_compression = 1;
+ if (compression_buffer_ready == 1)
+ return;
+ compression_buffer_ready = 1;
buffer_init(&compression_buffer);
- buffer_compress_init(level);
}
-/*
- * Encrypts the given number of bytes, copying from src to dest. bytes is
- * known to be a multiple of 8.
- */
-
void
-packet_encrypt(CipherContext * cc, void *dest, void *src,
- unsigned int bytes)
-{
- cipher_encrypt(cc, dest, src, bytes);
-}
-
-/*
- * Decrypts the given number of bytes, copying from src to dest. bytes is
- * known to be a multiple of 8.
- */
-
-void
-packet_decrypt(CipherContext * cc, void *dest, void *src,
- unsigned int bytes)
+packet_start_compression(int level)
{
- 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)
- packet_disconnect("crc32 compensation attack: network attack detected");
-
- cipher_decrypt(cc, dest, src, bytes);
+ if (packet_compression && !compat20)
+ fatal("Compression already enabled.");
+ packet_compression = 1;
+ packet_init_compression();
+ buffer_compress_init_send(level);
+ buffer_compress_init_recv();
}
/*
* key is used for both sending and reception. However, both directions are
* encrypted independently of each other.
*/
-
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. */
-
+/* Start constructing a packet to send. */
void
-packet_start1(int type)
+packet_start(u_char type)
{
- char buf[9];
+ u_char buf[9];
+ int len;
+ DBG(debug("packet_start[%d]", type));
+ len = compat20 ? 6 : 9;
+ memset(buf, 0, len - 1);
+ buf[len - 1] = type;
buffer_clear(&outgoing_packet);
- memset(buf, 0, 8);
- buf[8] = type;
- buffer_append(&outgoing_packet, buf, 9);
-}
-
-void
-packet_start2(int type)
-{
- char buf[4+1+1];
-
- buffer_clear(&outgoing_packet);
- memset(buf, 0, sizeof buf);
- /* buf[0..3] = payload_len; */
- /* buf[4] = pad_len; */
- buf[5] = type & 0xff;
- buffer_append(&outgoing_packet, buf, sizeof buf);
-}
-
-void
-packet_start(int type)
-{
- DBG(debug("packet_start[%d]",type));
- if (use_ssh2_packet_format)
- packet_start2(type);
- else
- packet_start1(type);
+ buffer_append(&outgoing_packet, buf, len);
}
-/* Appends a character to the packet data. */
-
+/* Append payload. */
void
packet_put_char(int value)
{
char ch = value;
buffer_append(&outgoing_packet, &ch, 1);
}
-
-/* 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 void *buf, u_int len)
{
buffer_put_string(&outgoing_packet, buf, len);
}
void
packet_put_cstring(const char *str)
{
- buffer_put_string(&outgoing_packet, str, strlen(str));
+ buffer_put_cstring(&outgoing_packet, str);
}
-
void
-packet_put_raw(const char *buf, unsigned int len)
+packet_put_raw(const void *buf, u_int len)
{
buffer_append(&outgoing_packet, buf, len);
}
-
-
-/* Appends an arbitrary precision integer to packet data. */
-
void
packet_put_bignum(BIGNUM * value)
{
* encrypts the packet before sending.
*/
-void
-packet_send1()
+static void
+packet_send1(void)
{
char buf[8], *cp;
int i, padding, len;
- unsigned int checksum;
+ u_int checksum;
u_int32_t rand = 0;
/*
buffer_compress(&outgoing_packet, &compression_buffer);
buffer_clear(&outgoing_packet);
buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
- buffer_len(&compression_buffer));
+ buffer_len(&compression_buffer));
}
/* Compute packet length without padding (add checksum, remove padding). */
len = buffer_len(&outgoing_packet) + 4 - 8;
- /* Insert padding. */
+ /* Insert padding. Initialized to zero in packet_start1() */
padding = 8 - len % 8;
- if (cipher_type != SSH_CIPHER_NONE) {
+ if (send_context.cipher->number != SSH_CIPHER_NONE) {
cp = buffer_ptr(&outgoing_packet);
for (i = 0; i < padding; i++) {
if (i % 4 == 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(buffer_ptr(&outgoing_packet),
+ buffer_len(&outgoing_packet));
PUT_32BIT(buf, checksum);
buffer_append(&outgoing_packet, buf, 4);
/* Append to output. */
PUT_32BIT(buf, len);
buffer_append(&output, buf, 4);
- buffer_append_space(&output, &cp, buffer_len(&outgoing_packet));
- packet_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),
- buffer_len(&outgoing_packet));
+ cp = buffer_append_space(&output, buffer_len(&outgoing_packet));
+ cipher_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),
+ buffer_len(&outgoing_packet));
#ifdef PACKET_DEBUG
fprintf(stderr, "encrypted: ");
*/
}
+static void
+set_newkeys(int mode)
+{
+ Enc *enc;
+ Mac *mac;
+ Comp *comp;
+ CipherContext *cc;
+
+ debug("newkeys: mode %d", mode);
+
+ cc = (mode == MODE_OUT) ? &send_context : &receive_context;
+ if (newkeys[mode] != NULL) {
+ debug("newkeys: rekeying");
+ /* todo: free old keys, reset compression/cipher-ctxt; */
+ memset(cc, 0, sizeof(*cc));
+ enc = &newkeys[mode]->enc;
+ mac = &newkeys[mode]->mac;
+ comp = &newkeys[mode]->comp;
+ memset(mac->key, 0, mac->key_len);
+ xfree(enc->name);
+ xfree(enc->iv);
+ xfree(enc->key);
+ xfree(mac->name);
+ xfree(mac->key);
+ xfree(comp->name);
+ xfree(newkeys[mode]);
+ }
+ newkeys[mode] = kex_get_newkeys(mode);
+ if (newkeys[mode] == NULL)
+ fatal("newkeys: no keys for mode %d", mode);
+ enc = &newkeys[mode]->enc;
+ mac = &newkeys[mode]->mac;
+ comp = &newkeys[mode]->comp;
+ if (mac->md != NULL)
+ mac->enabled = 1;
+ DBG(debug("cipher_init_context: %d", mode));
+ cipher_init(cc, enc->cipher, enc->key, enc->cipher->key_len,
+ enc->iv, enc->cipher->block_size);
+ memset(enc->iv, 0, enc->cipher->block_size);
+ memset(enc->key, 0, enc->cipher->key_len);
+ if (comp->type != 0 && comp->enabled == 0) {
+ 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)
*/
-void
-packet_send2()
+static void
+packet_send2(void)
{
- unsigned char *macbuf = NULL;
+ static u_int32_t seqnr = 0;
+ u_char type, *ucp, *macbuf = NULL;
+ u_char padlen, pad;
char *cp;
- unsigned int packet_length = 0;
- unsigned int i, padlen, len;
+ u_int packet_length = 0;
+ u_int i, len;
u_int32_t rand = 0;
- static unsigned int seqnr = 0;
- int type;
Enc *enc = NULL;
Mac *mac = NULL;
Comp *comp = NULL;
int block_size;
- if (kex != NULL) {
- enc = &kex->enc[MODE_OUT];
- mac = &kex->mac[MODE_OUT];
- comp = &kex->comp[MODE_OUT];
+ if (newkeys[MODE_OUT] != NULL) {
+ enc = &newkeys[MODE_OUT]->enc;
+ mac = &newkeys[MODE_OUT]->mac;
+ comp = &newkeys[MODE_OUT]->comp;
}
- block_size = enc ? enc->block_size : 8;
+ block_size = enc ? enc->cipher->block_size : 8;
- cp = buffer_ptr(&outgoing_packet);
- type = cp[5] & 0xff;
+ ucp = buffer_ptr(&outgoing_packet);
+ type = ucp[5];
#ifdef PACKET_DEBUG
fprintf(stderr, "plain: ");
padlen = block_size - (len % block_size);
if (padlen < 4)
padlen += block_size;
- buffer_append_space(&outgoing_packet, &cp, padlen);
- if (enc && enc->type != SSH_CIPHER_NONE) {
+ if (extra_pad) {
+ /* will wrap if extra_pad+padlen > 255 */
+ extra_pad = roundup(extra_pad, block_size);
+ pad = extra_pad - ((len + padlen) % extra_pad);
+ debug("packet_send2: adding %d (len %d padlen %d extra_pad %d)",
+ pad, len, padlen, extra_pad);
+ padlen += pad;
+ extra_pad = 0;
+ }
+ cp = buffer_append_space(&outgoing_packet, padlen);
+ if (enc && 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 */
+ memset(cp, 0, padlen);
}
/* packet_length includes payload, padding and padding length field */
packet_length = buffer_len(&outgoing_packet) - 4;
- cp = buffer_ptr(&outgoing_packet);
- PUT_32BIT(cp, packet_length);
- cp[4] = padlen & 0xff;
+ ucp = buffer_ptr(&outgoing_packet);
+ PUT_32BIT(ucp, packet_length);
+ ucp[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 = 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,
+ 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));
- packet_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),
+ cp = buffer_append_space(&output, buffer_len(&outgoing_packet));
+ cipher_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),
buffer_len(&outgoing_packet));
/* append unencrypted MAC */
if (mac && mac->enabled)
log("outgoing seqnr wraps around");
buffer_clear(&outgoing_packet);
- if (type == SSH2_MSG_NEWKEYS) {
- if (kex==NULL || mac==NULL || enc==NULL || comp==NULL)
- fatal("packet_send2: no KEX");
- if (mac->md != NULL)
- mac->enabled = 1;
- 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);
- clear_enc_keys(enc, kex->we_need);
- if (comp->type != 0 && comp->enabled == 0) {
- comp->enabled = 1;
- if (! packet_compression)
- packet_start_compression(6);
- }
- }
+ if (type == SSH2_MSG_NEWKEYS)
+ set_newkeys(MODE_OUT);
}
void
-packet_send()
+packet_send(void)
{
- if (use_ssh2_packet_format)
+ if (compat20)
packet_send2();
else
packet_send1();
DBG(debug("packet_send done"));
}
-void
-packet_send_and_wait()
-{
- packet_send();
- packet_write_wait();
-}
-
/*
* 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
*/
int
-packet_read(int *payload_len_ptr)
+packet_read_seqnr(u_int32_t *seqnr_p)
{
int type, len;
- fd_set set;
+ fd_set *setp;
char buf[8192];
DBG(debug("packet_read()"));
+ setp = (fd_set *)xmalloc(howmany(connection_in+1, NFDBITS) *
+ sizeof(fd_mask));
+
/* Since we are blocking, ensure that all written packets have been sent. */
packet_write_wait();
/* Stay in the loop until we have received a complete packet. */
for (;;) {
/* Try to read a packet from the buffer. */
- type = packet_read_poll(payload_len_ptr);
- if (type == SSH_SMSG_SUCCESS
+ 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_integrity_check(*payload_len_ptr, 0, type);
+ || type == SSH_CMSG_EXIT_CONFIRMATION))
+ packet_check_eom();
/* If we got a packet, return it. */
- if (type != SSH_MSG_NONE)
+ if (type != SSH_MSG_NONE) {
+ xfree(setp);
return type;
+ }
/*
* Otherwise, wait for some data to arrive, add it to the
* buffer, and try again.
*/
- FD_ZERO(&set);
- FD_SET(connection_in, &set);
+ memset(setp, 0, howmany(connection_in + 1, NFDBITS) *
+ sizeof(fd_mask));
+ FD_SET(connection_in, setp);
/* Wait for some data to arrive. */
- select(connection_in + 1, &set, NULL, NULL, NULL);
+ while (select(connection_in + 1, setp, NULL, NULL, NULL) == -1 &&
+ (errno == EAGAIN || errno == EINTR))
+ ;
/* Read data from the socket. */
len = read(connection_in, buf, sizeof(buf));
/* 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 *payload_len_ptr, int expected_type)
+packet_read_expect(int expected_type)
{
int type;
- type = packet_read(payload_len_ptr);
+ type = packet_read();
if (type != expected_type)
packet_disconnect("Protocol error: expected packet type %d, got %d",
expected_type, type);
* SSH_MSG_DISCONNECT is handled specially here. Also,
* SSH_MSG_IGNORE messages are skipped by this function and are never returned
* to higher levels.
- *
- * The returned payload_len does include space consumed by:
- * Packet length
- * Padding
- * Packet type
- * Check bytes
*/
-int
-packet_read_poll1(int *payload_len_ptr)
+static int
+packet_read_poll1(void)
{
- unsigned int len, padded_len;
- unsigned char *ucp;
- char buf[8], *cp;
- unsigned int checksum, stored_checksum;
+ u_int len, padded_len;
+ u_char *ucp, type;
+ char *cp;
+ 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 = buffer_ptr(&input);
len = GET_32BIT(ucp);
if (len < 1 + 2 + 2 || len > 256 * 1024)
packet_disconnect("Bad packet length %d.", len);
/* Consume packet length. */
buffer_consume(&input, 4);
- /* Copy data to incoming_packet. */
+ /*
+ * Cryptographic attack detector for ssh
+ * (C)1998 CORE-SDI, Buenos Aires Argentina
+ * Ariel Futoransky(futo@core-sdi.com)
+ */
+ if (receive_context.cipher->number != SSH_CIPHER_NONE &&
+ detect_attack(buffer_ptr(&input), padded_len, NULL) == DEATTACK_DETECTED)
+ packet_disconnect("crc32 compensation attack: network attack detected");
+
+ /* Decrypt data to incoming_packet. */
buffer_clear(&incoming_packet);
- buffer_append_space(&incoming_packet, &cp, padded_len);
- packet_decrypt(&receive_context, cp, buffer_ptr(&input), padded_len);
+ cp = buffer_append_space(&incoming_packet, padded_len);
+ cipher_decrypt(&receive_context, cp, buffer_ptr(&input), padded_len);
+
buffer_consume(&input, padded_len);
#ifdef PACKET_DEBUG
#endif
/* Compute packet checksum. */
- checksum = crc32((unsigned char *) buffer_ptr(&incoming_packet),
+ checksum = ssh_crc32(buffer_ptr(&incoming_packet),
buffer_len(&incoming_packet) - 4);
/* Skip padding. */
buffer_consume(&incoming_packet, 8 - len % 8);
/* Test check bytes. */
-
if (len != buffer_len(&incoming_packet))
- packet_disconnect("packet_read_poll: len %d != buffer_len %d.",
+ packet_disconnect("packet_read_poll1: 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.");
buffer_consume_end(&incoming_packet, 4);
- /* If using packet compression, decompress the packet. */
if (packet_compression) {
buffer_clear(&compression_buffer);
buffer_uncompress(&incoming_packet, &compression_buffer);
buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
buffer_len(&compression_buffer));
}
- /* Get packet type. */
- buffer_get(&incoming_packet, &buf[0], 1);
-
- /* Return length of payload (without type field). */
- *payload_len_ptr = buffer_len(&incoming_packet);
-
- /* Return type. */
- return (unsigned char) buf[0];
+ type = buffer_get_char(&incoming_packet);
+ return type;
}
-int
-packet_read_poll2(int *payload_len_ptr)
+static int
+packet_read_poll2(u_int32_t *seqnr_p)
{
- 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 *macbuf, *ucp, type;
char *cp;
- static unsigned int packet_length = 0;
- static unsigned int seqnr = 0;
- int type;
int maclen, block_size;
Enc *enc = NULL;
Mac *mac = NULL;
Comp *comp = NULL;
- if (kex != NULL) {
- enc = &kex->enc[MODE_IN];
- mac = &kex->mac[MODE_IN];
- comp = &kex->comp[MODE_IN];
+ if (newkeys[MODE_IN] != NULL) {
+ enc = &newkeys[MODE_IN]->enc;
+ mac = &newkeys[MODE_IN]->mac;
+ comp = &newkeys[MODE_IN]->comp;
}
maclen = mac && mac->enabled ? mac->mac_len : 0;
- block_size = enc ? enc->block_size : 8;
+ block_size = enc ? enc->cipher->block_size : 8;
if (packet_length == 0) {
/*
if (buffer_len(&input) < block_size)
return SSH_MSG_NONE;
buffer_clear(&incoming_packet);
- buffer_append_space(&incoming_packet, &cp, block_size);
- packet_decrypt(&receive_context, cp, buffer_ptr(&input),
+ cp = buffer_append_space(&incoming_packet, block_size);
+ cipher_decrypt(&receive_context, cp, buffer_ptr(&input),
block_size);
- ucp = (unsigned char *) buffer_ptr(&incoming_packet);
+ ucp = buffer_ptr(&incoming_packet);
packet_length = GET_32BIT(ucp);
if (packet_length < 1 + 4 || packet_length > 256 * 1024) {
buffer_dump(&incoming_packet);
fprintf(stderr, "read_poll enc/full: ");
buffer_dump(&input);
#endif
- buffer_append_space(&incoming_packet, &cp, need);
- packet_decrypt(&receive_context, cp, buffer_ptr(&input), need);
+ cp = buffer_append_space(&incoming_packet, need);
+ cipher_decrypt(&receive_context, cp, buffer_ptr(&input), need);
buffer_consume(&input, need);
/*
* compute MAC over seqnr and packet,
* increment sequence number for incoming packet
*/
if (mac && mac->enabled) {
- macbuf = hmac( mac->md, seqnr,
- (unsigned char *) buffer_ptr(&incoming_packet),
- buffer_len(&incoming_packet),
- mac->key, mac->key_len
- );
+ macbuf = mac_compute(mac, seqnr,
+ 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_p != NULL)
+ *seqnr_p = seqnr;
if (++seqnr == 0)
log("incoming seqnr wraps around");
/* get padlen */
- cp = buffer_ptr(&incoming_packet) + 4;
- padlen = *cp & 0xff;
+ cp = buffer_ptr(&incoming_packet);
+ cp += 4;
+ padlen = (u_char) *cp;
DBG(debug("input: padlen %d", padlen));
if (padlen < 4)
packet_disconnect("Corrupted padlen %d on input.", padlen);
* get packet type, implies consume.
* return length of payload (without type field)
*/
- buffer_get(&incoming_packet, (char *)&buf[0], 1);
- *payload_len_ptr = buffer_len(&incoming_packet);
-
- /* reset for next packet */
- packet_length = 0;
-
- /* extract packet type */
- type = (unsigned 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;
- 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);
- clear_enc_keys(enc, kex->we_need);
- if (comp->type != 0 && comp->enabled == 0) {
- comp->enabled = 1;
- if (! packet_compression)
- packet_start_compression(6);
- }
- }
-
+ type = buffer_get_char(&incoming_packet);
+ if (type == SSH2_MSG_NEWKEYS)
+ set_newkeys(MODE_IN);
#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;
+ /* reset for next packet */
+ packet_length = 0;
+ return type;
}
int
-packet_read_poll(int *payload_len_ptr)
+packet_read_poll_seqnr(u_int32_t *seqnr_p)
{
+ int reason, seqnr;
+ u_char type;
char *msg;
- for (;;) {
- int type = use_ssh2_packet_format ?
- packet_read_poll2(payload_len_ptr):
- packet_read_poll1(payload_len_ptr);
- if(compat20) {
- int reason;
- if (type != 0)
+ for (;;) {
+ if (compat20) {
+ type = packet_read_poll2(seqnr_p);
+ if (type)
DBG(debug("received packet type %d", type));
- switch(type) {
+ switch (type) {
case SSH2_MSG_IGNORE:
break;
case SSH2_MSG_DEBUG:
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;
+ case SSH2_MSG_UNIMPLEMENTED:
+ seqnr = packet_get_int();
+ debug("Received SSH2_MSG_UNIMPLEMENTED for %d", seqnr);
+ break;
default:
return type;
break;
- }
+ }
} else {
- switch(type) {
+ type = packet_read_poll1();
+ switch (type) {
case SSH_MSG_IGNORE:
break;
case SSH_MSG_DEBUG:
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;
default:
- if (type != 0)
+ if (type)
DBG(debug("received packet type %d", type));
return type;
break;
- }
+ }
}
}
}
+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, 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
-packet_get_char()
+u_int
+packet_get_char(void)
{
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
-packet_get_int()
+u_int
+packet_get_int(void)
{
return buffer_get_int(&incoming_packet);
}
*/
void
-packet_get_bignum(BIGNUM * value, int *length_ptr)
+packet_get_bignum(BIGNUM * value)
{
- *length_ptr = buffer_get_bignum(&incoming_packet, value);
+ buffer_get_bignum(&incoming_packet, value);
}
void
-packet_get_bignum2(BIGNUM * value, int *length_ptr)
+packet_get_bignum2(BIGNUM * value)
{
- *length_ptr = buffer_get_bignum2(&incoming_packet, value);
+ buffer_get_bignum2(&incoming_packet, value);
}
-char *
+void *
packet_get_raw(int *length_ptr)
{
int bytes = buffer_len(&incoming_packet);
* integer into which the length of the string is stored.
*/
-char *
-packet_get_string(unsigned int *length_ptr)
+void *
+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_start(SSH_MSG_DEBUG);
- packet_put_string(buf, strlen(buf));
+ 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();
}
packet_put_cstring("");
} else {
packet_start(SSH_MSG_DISCONNECT);
- packet_put_string(buf, strlen(buf));
+ packet_put_cstring(buf);
}
packet_send();
packet_write_wait();
/* Stop listening for connections. */
- channel_stop_listening();
+ channel_close_all();
/* Close the connection. */
packet_close();
/* Checks if there is any buffered output, and tries to write some of the output. */
void
-packet_write_poll()
+packet_write_poll(void)
{
int len = buffer_len(&output);
if (len > 0) {
*/
void
-packet_write_wait()
+packet_write_wait(void)
{
+ fd_set *setp;
+
+ setp = (fd_set *)xmalloc(howmany(connection_out + 1, NFDBITS) *
+ sizeof(fd_mask));
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);
+ memset(setp, 0, howmany(connection_out + 1, NFDBITS) *
+ sizeof(fd_mask));
+ FD_SET(connection_out, setp);
+ while (select(connection_out + 1, NULL, setp, NULL, NULL) == -1 &&
+ (errno == EAGAIN || errno == EINTR))
+ ;
packet_write_poll();
}
+ xfree(setp);
}
/* Returns true if there is buffered data to write to the connection. */
int
-packet_have_data_to_write()
+packet_have_data_to_write(void)
{
return buffer_len(&output) != 0;
}
/* Returns true if there is not too much data to write to the connection. */
int
-packet_not_very_much_data_to_write()
+packet_not_very_much_data_to_write(void)
{
if (interactive_mode)
return buffer_len(&output) < 16384;
/* 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)
{
- int on = 1;
+ static int called = 0;
+#if defined(IP_TOS) && !defined(IP_TOS_IS_BROKEN)
+ int lowdelay = IPTOS_LOWDELAY;
+ int throughput = IPTOS_THROUGHPUT;
+#endif
+
+ 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 (setsockopt(connection_in, IPPROTO_TCP, TCP_NODELAY, (void *) &on,
- sizeof(on)) < 0)
- error("setsockopt TCP_NODELAY: %.100s", strerror(errno));
- } else {
+#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
+ set_nodelay(connection_in);
+ } 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
}
}
/* Returns true if the current connection is interactive. */
int
-packet_is_interactive()
+packet_is_interactive(void)
{
return interactive_mode;
}
log("packet_set_maxsize: bad size %d", s);
return -1;
}
- log("packet_set_maxsize: setting to %d", s);
+ called = 1;
+ debug("packet_set_maxsize: setting to %d", s);
max_packet_size = s;
return s;
}
+
+/* roundup current message to pad bytes */
+void
+packet_add_padding(u_char pad)
+{
+ extra_pad = pad;
+}
+
+/*
+ * 9.2. Ignored Data Message
+ *
+ * byte SSH_MSG_IGNORE
+ * string data
+ *
+ * All implementations MUST understand (and ignore) this message at any
+ * time (after receiving the protocol version). No implementation is
+ * required to send them. This message can be used as an additional
+ * protection measure against advanced traffic analysis techniques.
+ */
+void
+packet_send_ignore(int nbytes)
+{
+ u_int32_t 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