/*
- *
- * 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 1.65 2001/06/07 20:23:04 markus 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 "deattack.h"
+#include "channels.h"
+
+#include "compat.h"
+#include "ssh1.h"
+#include "ssh2.h"
+
+#include "cipher.h"
+#include "kex.h"
+#include "mac.h"
+#include "log.h"
+#include "canohost.h"
+
+#ifdef PACKET_DEBUG
+#define DBG(x) x
+#else
+#define DBG(x)
+#endif
/*
* This variable contains the file descriptors used for communicating with
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;
+/* Session key information for Encryption and MAC */
+Newkeys *newkeys[MODE_MAX];
+
/*
* 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'");
connection_in = fd_in;
connection_out = fd_out;
- cipher_type = SSH_CIPHER_NONE;
- cipher_set_key(&send_context, SSH_CIPHER_NONE, (unsigned char *) "", 0, 1);
- cipher_set_key(&receive_context, SSH_CIPHER_NONE, (unsigned char *) "", 0, 0);
+ cipher_init(&send_context, none, (u_char *) "", 0, NULL, 0);
+ cipher_init(&receive_context, none, (u_char *) "", 0, NULL, 0);
+ newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL;
if (!initialized) {
initialized = 1;
buffer_init(&input);
fatal_add_cleanup((void (*) (void *)) packet_close, NULL);
}
+/* Returns 1 if remote host is connected via socket, 0 if not. */
+
+int
+packet_connection_is_on_socket()
+{
+ struct sockaddr_storage from, to;
+ socklen_t fromlen, tolen;
+
+ /* filedescriptors in and out are the same, so it's a socket */
+ if (connection_in == connection_out)
+ return 1;
+ fromlen = sizeof(from);
+ memset(&from, 0, sizeof(from));
+ if (getpeername(connection_in, (struct sockaddr *)&from, &fromlen) < 0)
+ return 0;
+ tolen = sizeof(to);
+ memset(&to, 0, sizeof(to));
+ if (getpeername(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;
+}
+
+/* returns 1 if connection is via ipv4 */
+
+int
+packet_connection_is_ipv4()
+{
+ struct sockaddr_storage to;
+ socklen_t tolen = sizeof(to);
+
+ memset(&to, 0, sizeof(to));
+ if (getsockname(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
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
+u_int
packet_get_protocol_flags()
{
return remote_protocol_flags;
*/
void
-packet_start_compression(int level)
+packet_init_compression()
{
- 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)
- */
-
- switch (cc->type) {
- case SSH_CIPHER_NONE:
- i = DEATTACK_OK;
- break;
- default:
- i = detect_attack(src, bytes, NULL);
- break;
- }
-
- 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)
{
- /* All other ciphers use the same key in both directions for now. */
- cipher_set_key(&receive_context, cipher, key, keylen, 0);
- cipher_set_key(&send_context, cipher, key, keylen, 1);
+ 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);
+ 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_start(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);
+ 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 char *buf, u_int len)
{
buffer_put_string(&outgoing_packet, buf, len);
}
-
-/* Appends an arbitrary precision integer to packet data. */
-
+void
+packet_put_cstring(const char *str)
+{
+ buffer_put_cstring(&outgoing_packet, str);
+}
+void
+packet_put_raw(const char *buf, u_int len)
+{
+ buffer_append(&outgoing_packet, buf, len);
+}
void
packet_put_bignum(BIGNUM * value)
{
buffer_put_bignum(&outgoing_packet, value);
}
+void
+packet_put_bignum2(BIGNUM * value)
+{
+ buffer_put_bignum2(&outgoing_packet, value);
+}
/*
* Finalizes and sends the packet. If the encryption key has been set,
*/
void
-packet_send()
+packet_send1(void)
{
char buf[8], *cp;
int i, padding, len;
- unsigned int checksum;
+ u_int checksum;
u_int32_t rand = 0;
/*
/* 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((u_char *) buffer_ptr(&outgoing_packet),
+ buffer_len(&outgoing_packet));
PUT_32BIT(buf, checksum);
buffer_append(&outgoing_packet, buf, 4);
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),
+ cipher_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),
buffer_len(&outgoing_packet));
#ifdef PACKET_DEBUG
*/
}
+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(void)
+{
+ static u_int32_t seqnr = 0;
+ u_char type, *ucp, *macbuf = NULL;
+ char *cp;
+ u_int packet_length = 0;
+ u_int i, padlen, len;
+ u_int32_t rand = 0;
+ Enc *enc = NULL;
+ Mac *mac = NULL;
+ Comp *comp = NULL;
+ int block_size;
+
+ if (newkeys[MODE_OUT] != NULL) {
+ enc = &newkeys[MODE_OUT]->enc;
+ mac = &newkeys[MODE_OUT]->mac;
+ comp = &newkeys[MODE_OUT]->comp;
+ }
+ block_size = enc ? enc->cipher->block_size : 8;
+
+ ucp = (u_char *) buffer_ptr(&outgoing_packet);
+ type = ucp[5];
+
+#ifdef PACKET_DEBUG
+ fprintf(stderr, "plain: ");
+ buffer_dump(&outgoing_packet);
+#endif
+
+ if (comp && comp->enabled) {
+ len = buffer_len(&outgoing_packet);
+ /* skip header, compress only payload */
+ buffer_consume(&outgoing_packet, 5);
+ buffer_clear(&compression_buffer);
+ buffer_compress(&outgoing_packet, &compression_buffer);
+ buffer_clear(&outgoing_packet);
+ buffer_append(&outgoing_packet, "\0\0\0\0\0", 5);
+ buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),
+ buffer_len(&compression_buffer));
+ DBG(debug("compression: raw %d compressed %d", len,
+ buffer_len(&outgoing_packet)));
+ }
+
+ /* sizeof (packet_len + pad_len + payload) */
+ len = buffer_len(&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;
+ buffer_append_space(&outgoing_packet, &cp, 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;
+ }
+ } else {
+ /* clear padding */
+ memset(cp, 0, padlen);
+ }
+ /* packet_length includes payload, padding and padding length field */
+ packet_length = buffer_len(&outgoing_packet) - 4;
+ ucp = (u_char *)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 = 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));
+ cipher_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),
+ buffer_len(&outgoing_packet));
+ /* append unencrypted MAC */
+ if (mac && mac->enabled)
+ buffer_append(&output, (char *)macbuf, mac->mac_len);
+#ifdef PACKET_DEBUG
+ fprintf(stderr, "encrypted: ");
+ buffer_dump(&output);
+#endif
+ /* increment sequence number for outgoing packets */
+ if (++seqnr == 0)
+ log("outgoing seqnr wraps around");
+ buffer_clear(&outgoing_packet);
+
+ if (type == SSH2_MSG_NEWKEYS)
+ set_newkeys(MODE_OUT);
+}
+
+void
+packet_send()
+{
+ 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
packet_read(int *payload_len_ptr)
{
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();
for (;;) {
/* Try to read a packet from the buffer. */
type = packet_read_poll(payload_len_ptr);
- if (type == SSH_SMSG_SUCCESS
+ if (!compat20 && (
+ type == SSH_SMSG_SUCCESS
|| type == SSH_SMSG_FAILURE
|| type == SSH_CMSG_EOF
- || type == SSH_CMSG_EXIT_CONFIRMATION)
+ || type == SSH_CMSG_EXIT_CONFIRMATION))
packet_integrity_check(*payload_len_ptr, 0, type);
/* 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));
- if (len == 0)
- fatal("Connection closed by %.200s", get_remote_ipaddr());
+ if (len == 0) {
+ log("Connection closed by %.200s", get_remote_ipaddr());
+ fatal_cleanup();
+ }
if (len < 0)
fatal("Read from socket failed: %.100s", strerror(errno));
/* Append it to the buffer. */
type = packet_read(payload_len_ptr);
if (type != expected_type)
packet_disconnect("Protocol error: expected packet type %d, got %d",
- expected_type, type);
+ expected_type, type);
}
/* Checks if a full packet is available in the data received so far via
*/
int
-packet_read_poll(int *payload_len_ptr)
+packet_read_poll1(int *payload_len_ptr)
{
- unsigned int len, padded_len;
- unsigned char *ucp;
- char buf[8], *cp;
- unsigned int checksum, stored_checksum;
-
-restart:
+ 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 = (u_char *) 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);
+ 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),
- buffer_len(&incoming_packet) - 4);
+ checksum = ssh_crc32((u_char *) 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.",
- len, buffer_len(&incoming_packet));
+ 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_clear(&incoming_packet);
buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
- buffer_len(&compression_buffer));
+ buffer_len(&compression_buffer));
}
- /* Get packet type. */
- buffer_get(&incoming_packet, &buf[0], 1);
-
- /* Return length of payload (without type field). */
+ type = buffer_get_char(&incoming_packet);
*payload_len_ptr = buffer_len(&incoming_packet);
+ return type;
+}
- /* Handle disconnect message. */
- if ((unsigned char) buf[0] == SSH_MSG_DISCONNECT) {
- log("Received disconnect: %.900s", packet_get_string(NULL));
- fatal_cleanup();
- }
+int
+packet_read_poll2(int *payload_len_ptr)
+{
+ static u_int32_t seqnr = 0;
+ static u_int packet_length = 0;
+ u_int padlen, need;
+ u_char *macbuf, *ucp, type;
+ char *cp;
+ int maclen, block_size;
+ Enc *enc = NULL;
+ Mac *mac = NULL;
+ Comp *comp = NULL;
+
+ 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->cipher->block_size : 8;
- /* Ignore ignore messages. */
- if ((unsigned char) buf[0] == SSH_MSG_IGNORE)
- goto restart;
+ if (packet_length == 0) {
+ /*
+ * check if input size is less than the cipher block size,
+ * decrypt first block and extract length of incoming packet
+ */
+ if (buffer_len(&input) < block_size)
+ return SSH_MSG_NONE;
+ buffer_clear(&incoming_packet);
+ buffer_append_space(&incoming_packet, &cp, block_size);
+ cipher_decrypt(&receive_context, cp, buffer_ptr(&input),
+ block_size);
+ 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);
+ packet_disconnect("Bad packet length %d.", packet_length);
+ }
+ DBG(debug("input: packet len %d", packet_length+4));
+ buffer_consume(&input, block_size);
+ }
+ /* we have a partial packet of block_size bytes */
+ need = 4 + packet_length - block_size;
+ DBG(debug("partial packet %d, need %d, maclen %d", block_size,
+ need, maclen));
+ if (need % block_size != 0)
+ fatal("padding error: need %d block %d mod %d",
+ need, block_size, need % block_size);
+ /*
+ * check if the entire packet has been received and
+ * decrypt into incoming_packet
+ */
+ if (buffer_len(&input) < need + maclen)
+ return SSH_MSG_NONE;
+#ifdef PACKET_DEBUG
+ fprintf(stderr, "read_poll enc/full: ");
+ buffer_dump(&input);
+#endif
+ buffer_append_space(&incoming_packet, &cp, 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 = 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 MAC on input.");
+ DBG(debug("MAC #%d ok", seqnr));
+ buffer_consume(&input, mac->mac_len);
+ }
+ if (++seqnr == 0)
+ log("incoming seqnr wraps around");
+
+ /* get padlen */
+ cp = buffer_ptr(&incoming_packet) + 4;
+ padlen = (u_char) *cp;
+ 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(&incoming_packet, 4 + 1);
+ buffer_consume_end(&incoming_packet, padlen);
+
+ DBG(debug("input: len before de-compress %d", buffer_len(&incoming_packet)));
+ if (comp && comp->enabled) {
+ buffer_clear(&compression_buffer);
+ buffer_uncompress(&incoming_packet, &compression_buffer);
+ buffer_clear(&incoming_packet);
+ buffer_append(&incoming_packet, buffer_ptr(&compression_buffer),
+ buffer_len(&compression_buffer));
+ DBG(debug("input: len after de-compress %d", buffer_len(&incoming_packet)));
+ }
+ /*
+ * get packet type, implies consume.
+ * return length of payload (without type field)
+ */
+ type = buffer_get_char(&incoming_packet);
+ if (type == SSH2_MSG_NEWKEYS)
+ set_newkeys(MODE_IN);
+ *payload_len_ptr = buffer_len(&incoming_packet);
+#ifdef PACKET_DEBUG
+ fprintf(stderr, "read/plain[%d]:\r\n", type);
+ buffer_dump(&incoming_packet);
+#endif
+ /* reset for next packet */
+ packet_length = 0;
+ return type;
+}
- /* Send debug messages as debugging output. */
- if ((unsigned char) buf[0] == SSH_MSG_DEBUG) {
- debug("Remote: %.900s", packet_get_string(NULL));
- goto restart;
+int
+packet_read_poll(int *payload_len_ptr)
+{
+ int reason;
+ u_char type;
+ char *msg;
+
+ for (;;) {
+ if (compat20) {
+ type = packet_read_poll2(payload_len_ptr);
+ if (type)
+ DBG(debug("received packet type %d", type));
+ switch(type) {
+ case 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);
+ log("Received disconnect from %s: %d: %.400s", get_remote_ipaddr(),
+ reason, msg);
+ xfree(msg);
+ fatal_cleanup();
+ break;
+ default:
+ return type;
+ break;
+ }
+ } else {
+ type = packet_read_poll1(payload_len_ptr);
+ 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);
+ log("Received disconnect from %s: %.400s", get_remote_ipaddr(),
+ msg);
+ fatal_cleanup();
+ xfree(msg);
+ break;
+ default:
+ if (type)
+ DBG(debug("received packet type %d", type));
+ return type;
+ break;
+ }
+ }
}
- /* Return type. */
- return (unsigned char) buf[0];
}
/*
*/
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);
*length_ptr = buffer_get_bignum(&incoming_packet, value);
}
+void
+packet_get_bignum2(BIGNUM * value, int *length_ptr)
+{
+ *length_ptr = buffer_get_bignum2(&incoming_packet, value);
+}
+
+char *
+packet_get_raw(int *length_ptr)
+{
+ int bytes = buffer_len(&incoming_packet);
+ if (length_ptr != NULL)
+ *length_ptr = bytes;
+ return buffer_ptr(&incoming_packet);
+}
+
+int
+packet_remaining(void)
+{
+ return buffer_len(&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
*/
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_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();
}
va_end(args);
/* Send the disconnect message to the other side, and wait for it to get sent. */
- packet_start(SSH_MSG_DISCONNECT);
- packet_put_string(buf, strlen(buf));
+ 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();
void
packet_write_wait()
{
+ 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. */
/* 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;
/*
- * Only set socket options if using a socket (as indicated by the
- * descriptors being the same).
+ * IPTOS_LOWDELAY and IPTOS_THROUGHPUT are IPv4 only
*/
- if (connection_in != connection_out)
- 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));
- }
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)
+ 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)
+ sizeof(throughput)) < 0)
error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno));
+#endif
}
}
{
static int called = 0;
if (called) {
- log("packet_set_maxsize: called twice: old %d new %d", max_packet_size, s);
+ log("packet_set_maxsize: called twice: old %d new %d",
+ max_packet_size, s);
return -1;
}
if (s < 4 * 1024 || s > 1024 * 1024) {
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 (compat20 == 0)
+ return;
+
+ have = buffer_len(&outgoing_packet);
+ debug2("packet_inject_ignore: current %d", have);
+ if (newkeys[MODE_OUT] != NULL)
+ enc = &newkeys[MODE_OUT]->enc;
+ 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