version 1.38, 2000/10/12 14:21:12 |
version 1.38.2.6, 2001/11/15 00:14:59 |
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* |
* |
* |
* |
* SSH2 packet format added by Markus Friedl. |
* SSH2 packet format added by Markus Friedl. |
* Copyright (c) 2000 Markus Friedl. All rights reserved. |
* Copyright (c) 2000, 2001 Markus Friedl. All rights reserved. |
* |
* |
* Redistribution and use in source and binary forms, with or without |
* Redistribution and use in source and binary forms, with or without |
* modification, are permitted provided that the following conditions |
* modification, are permitted provided that the following conditions |
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#include "buffer.h" |
#include "buffer.h" |
#include "packet.h" |
#include "packet.h" |
#include "bufaux.h" |
#include "bufaux.h" |
#include "ssh.h" |
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#include "crc32.h" |
#include "crc32.h" |
#include "getput.h" |
#include "getput.h" |
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#include "channels.h" |
#include "channels.h" |
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#include "compat.h" |
#include "compat.h" |
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#include "ssh1.h" |
#include "ssh2.h" |
#include "ssh2.h" |
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#include <openssl/bn.h> |
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#include <openssl/dh.h> |
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#include <openssl/hmac.h> |
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#include "buffer.h" |
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#include "cipher.h" |
#include "cipher.h" |
#include "kex.h" |
#include "kex.h" |
#include "hmac.h" |
#include "mac.h" |
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#include "log.h" |
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#include "canohost.h" |
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#ifdef PACKET_DEBUG |
#ifdef PACKET_DEBUG |
#define DBG(x) x |
#define DBG(x) x |
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static int connection_in = -1; |
static int connection_in = -1; |
static int connection_out = -1; |
static int connection_out = -1; |
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/* |
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* Cipher type. This value is only used to determine whether to pad the |
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* packets with zeroes or random data. |
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*/ |
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static int cipher_type = SSH_CIPHER_NONE; |
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/* Protocol flags for the remote side. */ |
/* Protocol flags for the remote side. */ |
static unsigned int remote_protocol_flags = 0; |
static u_int remote_protocol_flags = 0; |
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/* Encryption context for receiving data. This is only used for decryption. */ |
/* Encryption context for receiving data. This is only used for decryption. */ |
static CipherContext receive_context; |
static CipherContext receive_context; |
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/* Scratch buffer for packet compression/decompression. */ |
/* Scratch buffer for packet compression/decompression. */ |
static Buffer compression_buffer; |
static Buffer compression_buffer; |
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static int compression_buffer_ready = 0; |
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/* Flag indicating whether packet compression/decompression is enabled. */ |
/* Flag indicating whether packet compression/decompression is enabled. */ |
static int packet_compression = 0; |
static int packet_compression = 0; |
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/* Set to true if the connection is interactive. */ |
/* Set to true if the connection is interactive. */ |
static int interactive_mode = 0; |
static int interactive_mode = 0; |
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/* True if SSH2 packet format is used */ |
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int use_ssh2_packet_format = 0; |
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/* Session key information for Encryption and MAC */ |
/* Session key information for Encryption and MAC */ |
Kex *kex = NULL; |
Newkeys *newkeys[MODE_MAX]; |
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void |
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packet_set_kex(Kex *k) |
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{ |
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if( k->mac[MODE_IN ].key == NULL || |
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k->enc[MODE_IN ].key == NULL || |
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k->enc[MODE_IN ].iv == NULL || |
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k->mac[MODE_OUT].key == NULL || |
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k->enc[MODE_OUT].key == NULL || |
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k->enc[MODE_OUT].iv == NULL) |
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fatal("bad KEX"); |
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kex = k; |
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} |
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void |
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clear_enc_keys(Enc *enc, int len) |
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{ |
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memset(enc->iv, 0, len); |
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memset(enc->key, 0, len); |
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xfree(enc->iv); |
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xfree(enc->key); |
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enc->iv = NULL; |
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enc->key = NULL; |
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} |
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void |
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packet_set_ssh2_format(void) |
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{ |
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DBG(debug("use_ssh2_packet_format")); |
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use_ssh2_packet_format = 1; |
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} |
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/* |
/* |
* Sets the descriptors used for communication. Disables encryption until |
* Sets the descriptors used for communication. Disables encryption until |
* packet_set_encryption_key is called. |
* packet_set_encryption_key is called. |
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fatal("packet_set_connection: cannot load cipher 'none'"); |
fatal("packet_set_connection: cannot load cipher 'none'"); |
connection_in = fd_in; |
connection_in = fd_in; |
connection_out = fd_out; |
connection_out = fd_out; |
cipher_type = SSH_CIPHER_NONE; |
cipher_init(&send_context, none, (u_char *) "", 0, NULL, 0); |
cipher_init(&send_context, none, (unsigned char *) "", 0, NULL, 0); |
cipher_init(&receive_context, none, (u_char *) "", 0, NULL, 0); |
cipher_init(&receive_context, none, (unsigned char *) "", 0, NULL, 0); |
newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL; |
if (!initialized) { |
if (!initialized) { |
initialized = 1; |
initialized = 1; |
buffer_init(&input); |
buffer_init(&input); |
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buffer_free(&output); |
buffer_free(&output); |
buffer_free(&outgoing_packet); |
buffer_free(&outgoing_packet); |
buffer_free(&incoming_packet); |
buffer_free(&incoming_packet); |
if (packet_compression) { |
if (compression_buffer_ready) { |
buffer_free(&compression_buffer); |
buffer_free(&compression_buffer); |
buffer_compress_uninit(); |
buffer_compress_uninit(); |
} |
} |
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/* Sets remote side protocol flags. */ |
/* Sets remote side protocol flags. */ |
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void |
void |
packet_set_protocol_flags(unsigned int protocol_flags) |
packet_set_protocol_flags(u_int protocol_flags) |
{ |
{ |
remote_protocol_flags = protocol_flags; |
remote_protocol_flags = protocol_flags; |
channel_set_options((protocol_flags & SSH_PROTOFLAG_HOST_IN_FWD_OPEN) != 0); |
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} |
} |
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/* Returns the remote protocol flags set earlier by the above function. */ |
/* Returns the remote protocol flags set earlier by the above function. */ |
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unsigned int |
u_int |
packet_get_protocol_flags() |
packet_get_protocol_flags() |
{ |
{ |
return remote_protocol_flags; |
return remote_protocol_flags; |
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* Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. |
* Level is compression level 1 (fastest) - 9 (slow, best) as in gzip. |
*/ |
*/ |
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/*** XXXXX todo: kex means re-init */ |
static void |
void |
packet_init_compression(void) |
packet_start_compression(int level) |
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{ |
{ |
if (packet_compression) |
if (compression_buffer_ready == 1) |
fatal("Compression already enabled."); |
return; |
packet_compression = 1; |
compression_buffer_ready = 1; |
buffer_init(&compression_buffer); |
buffer_init(&compression_buffer); |
buffer_compress_init(level); |
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} |
} |
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/* |
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* Encrypts the given number of bytes, copying from src to dest. bytes is |
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* known to be a multiple of 8. |
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*/ |
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void |
void |
packet_encrypt(CipherContext * cc, void *dest, void *src, |
packet_start_compression(int level) |
unsigned int bytes) |
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{ |
{ |
cipher_encrypt(cc, dest, src, bytes); |
if (packet_compression && !compat20) |
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fatal("Compression already enabled."); |
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packet_compression = 1; |
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packet_init_compression(); |
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buffer_compress_init_send(level); |
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buffer_compress_init_recv(); |
} |
} |
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/* |
/* |
* Decrypts the given number of bytes, copying from src to dest. bytes is |
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* known to be a multiple of 8. |
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*/ |
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void |
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packet_decrypt(CipherContext *context, void *dest, void *src, unsigned int bytes) |
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{ |
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/* |
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* Cryptographic attack detector for ssh - Modifications for packet.c |
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* (C)1998 CORE-SDI, Buenos Aires Argentina Ariel Futoransky(futo@core-sdi.com) |
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*/ |
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if (!compat20 && |
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context->cipher->number != SSH_CIPHER_NONE && |
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detect_attack(src, bytes, NULL) == DEATTACK_DETECTED) |
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packet_disconnect("crc32 compensation attack: network attack detected"); |
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cipher_decrypt(context, dest, src, bytes); |
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} |
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/* |
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* Causes any further packets to be encrypted using the given key. The same |
* 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 |
* key is used for both sending and reception. However, both directions are |
* encrypted independently of each other. |
* encrypted independently of each other. |
*/ |
*/ |
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void |
void |
packet_set_encryption_key(const unsigned char *key, unsigned int keylen, |
packet_set_encryption_key(const u_char *key, u_int keylen, |
int number) |
int number) |
{ |
{ |
Cipher *cipher = cipher_by_number(number); |
Cipher *cipher = cipher_by_number(number); |
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cipher_init(&send_context, cipher, key, keylen, NULL, 0); |
cipher_init(&send_context, cipher, key, keylen, NULL, 0); |
} |
} |
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/* Starts constructing a packet to send. */ |
/* Start constructing a packet to send. */ |
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void |
void |
packet_start1(int type) |
packet_start(u_char type) |
{ |
{ |
char buf[9]; |
u_char buf[9]; |
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int len; |
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DBG(debug("packet_start[%d]", type)); |
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len = compat20 ? 6 : 9; |
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memset(buf, 0, len - 1); |
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buf[len - 1] = type; |
buffer_clear(&outgoing_packet); |
buffer_clear(&outgoing_packet); |
memset(buf, 0, 8); |
buffer_append(&outgoing_packet, buf, len); |
buf[8] = type; |
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buffer_append(&outgoing_packet, buf, 9); |
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} |
} |
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/* Append payload. */ |
void |
void |
packet_start2(int type) |
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{ |
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char buf[4+1+1]; |
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buffer_clear(&outgoing_packet); |
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memset(buf, 0, sizeof buf); |
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/* buf[0..3] = payload_len; */ |
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/* buf[4] = pad_len; */ |
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buf[5] = type & 0xff; |
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buffer_append(&outgoing_packet, buf, sizeof buf); |
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} |
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void |
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packet_start(int type) |
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{ |
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DBG(debug("packet_start[%d]",type)); |
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if (use_ssh2_packet_format) |
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packet_start2(type); |
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else |
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packet_start1(type); |
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} |
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/* Appends a character to the packet data. */ |
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void |
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packet_put_char(int value) |
packet_put_char(int value) |
{ |
{ |
char ch = value; |
char ch = value; |
buffer_append(&outgoing_packet, &ch, 1); |
buffer_append(&outgoing_packet, &ch, 1); |
} |
} |
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/* Appends an integer to the packet data. */ |
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void |
void |
packet_put_int(unsigned int value) |
packet_put_int(u_int value) |
{ |
{ |
buffer_put_int(&outgoing_packet, value); |
buffer_put_int(&outgoing_packet, value); |
} |
} |
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/* Appends a string to packet data. */ |
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void |
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); |
buffer_put_string(&outgoing_packet, buf, len); |
} |
} |
void |
void |
packet_put_cstring(const char *str) |
packet_put_cstring(const char *str) |
{ |
{ |
buffer_put_string(&outgoing_packet, str, strlen(str)); |
buffer_put_cstring(&outgoing_packet, str); |
} |
} |
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void |
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); |
buffer_append(&outgoing_packet, buf, len); |
} |
} |
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/* Appends an arbitrary precision integer to packet data. */ |
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void |
void |
packet_put_bignum(BIGNUM * value) |
packet_put_bignum(BIGNUM * value) |
{ |
{ |
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* encrypts the packet before sending. |
* encrypts the packet before sending. |
*/ |
*/ |
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void |
static void |
packet_send1() |
packet_send1(void) |
{ |
{ |
char buf[8], *cp; |
char buf[8], *cp; |
int i, padding, len; |
int i, padding, len; |
unsigned int checksum; |
u_int checksum; |
u_int32_t rand = 0; |
u_int32_t rand = 0; |
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/* |
/* |
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/* Insert padding. Initialized to zero in packet_start1() */ |
/* Insert padding. Initialized to zero in packet_start1() */ |
padding = 8 - len % 8; |
padding = 8 - len % 8; |
if (cipher_type != SSH_CIPHER_NONE) { |
if (send_context.cipher->number != SSH_CIPHER_NONE) { |
cp = buffer_ptr(&outgoing_packet); |
cp = buffer_ptr(&outgoing_packet); |
for (i = 0; i < padding; i++) { |
for (i = 0; i < padding; i++) { |
if (i % 4 == 0) |
if (i % 4 == 0) |
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buffer_consume(&outgoing_packet, 8 - padding); |
buffer_consume(&outgoing_packet, 8 - padding); |
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/* Add check bytes. */ |
/* Add check bytes. */ |
checksum = ssh_crc32((unsigned char *) buffer_ptr(&outgoing_packet), |
checksum = ssh_crc32((u_char *) buffer_ptr(&outgoing_packet), |
buffer_len(&outgoing_packet)); |
buffer_len(&outgoing_packet)); |
PUT_32BIT(buf, checksum); |
PUT_32BIT(buf, checksum); |
buffer_append(&outgoing_packet, buf, 4); |
buffer_append(&outgoing_packet, buf, 4); |
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PUT_32BIT(buf, len); |
PUT_32BIT(buf, len); |
buffer_append(&output, buf, 4); |
buffer_append(&output, buf, 4); |
buffer_append_space(&output, &cp, buffer_len(&outgoing_packet)); |
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)); |
buffer_len(&outgoing_packet)); |
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#ifdef PACKET_DEBUG |
#ifdef PACKET_DEBUG |
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*/ |
*/ |
} |
} |
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static void |
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set_newkeys(int mode) |
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{ |
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Enc *enc; |
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Mac *mac; |
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Comp *comp; |
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CipherContext *cc; |
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debug("newkeys: mode %d", mode); |
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cc = (mode == MODE_OUT) ? &send_context : &receive_context; |
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if (newkeys[mode] != NULL) { |
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debug("newkeys: rekeying"); |
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/* todo: free old keys, reset compression/cipher-ctxt; */ |
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memset(cc, 0, sizeof(*cc)); |
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enc = &newkeys[mode]->enc; |
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mac = &newkeys[mode]->mac; |
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comp = &newkeys[mode]->comp; |
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memset(mac->key, 0, mac->key_len); |
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xfree(enc->name); |
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xfree(enc->iv); |
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xfree(enc->key); |
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xfree(mac->name); |
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xfree(mac->key); |
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xfree(comp->name); |
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xfree(newkeys[mode]); |
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} |
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newkeys[mode] = kex_get_newkeys(mode); |
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if (newkeys[mode] == NULL) |
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fatal("newkeys: no keys for mode %d", mode); |
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enc = &newkeys[mode]->enc; |
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mac = &newkeys[mode]->mac; |
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comp = &newkeys[mode]->comp; |
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if (mac->md != NULL) |
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mac->enabled = 1; |
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DBG(debug("cipher_init_context: %d", mode)); |
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cipher_init(cc, enc->cipher, enc->key, enc->cipher->key_len, |
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enc->iv, enc->cipher->block_size); |
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memset(enc->iv, 0, enc->cipher->block_size); |
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memset(enc->key, 0, enc->cipher->key_len); |
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if (comp->type != 0 && comp->enabled == 0) { |
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packet_init_compression(); |
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if (mode == MODE_OUT) |
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buffer_compress_init_send(6); |
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else |
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buffer_compress_init_recv(); |
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comp->enabled = 1; |
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} |
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} |
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/* |
/* |
* Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) |
* Finalize packet in SSH2 format (compress, mac, encrypt, enqueue) |
*/ |
*/ |
void |
static void |
packet_send2() |
packet_send2(void) |
{ |
{ |
unsigned char *macbuf = NULL; |
static u_int32_t seqnr = 0; |
|
u_char type, *ucp, *macbuf = NULL; |
char *cp; |
char *cp; |
unsigned int packet_length = 0; |
u_int packet_length = 0; |
unsigned int i, padlen, len; |
u_int i, padlen, len; |
u_int32_t rand = 0; |
u_int32_t rand = 0; |
static unsigned int seqnr = 0; |
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int type; |
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Enc *enc = NULL; |
Enc *enc = NULL; |
Mac *mac = NULL; |
Mac *mac = NULL; |
Comp *comp = NULL; |
Comp *comp = NULL; |
int block_size; |
int block_size; |
|
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if (kex != NULL) { |
if (newkeys[MODE_OUT] != NULL) { |
enc = &kex->enc[MODE_OUT]; |
enc = &newkeys[MODE_OUT]->enc; |
mac = &kex->mac[MODE_OUT]; |
mac = &newkeys[MODE_OUT]->mac; |
comp = &kex->comp[MODE_OUT]; |
comp = &newkeys[MODE_OUT]->comp; |
} |
} |
block_size = enc ? enc->cipher->block_size : 8; |
block_size = enc ? enc->cipher->block_size : 8; |
|
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cp = buffer_ptr(&outgoing_packet); |
ucp = (u_char *) buffer_ptr(&outgoing_packet); |
type = cp[5] & 0xff; |
type = ucp[5]; |
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#ifdef PACKET_DEBUG |
#ifdef PACKET_DEBUG |
fprintf(stderr, "plain: "); |
fprintf(stderr, "plain: "); |
|
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if (i % 4 == 0) |
if (i % 4 == 0) |
rand = arc4random(); |
rand = arc4random(); |
cp[i] = rand & 0xff; |
cp[i] = rand & 0xff; |
rand <<= 8; |
rand >>= 8; |
} |
} |
} else { |
} else { |
/* clear padding */ |
/* clear padding */ |
|
|
} |
} |
/* packet_length includes payload, padding and padding length field */ |
/* packet_length includes payload, padding and padding length field */ |
packet_length = buffer_len(&outgoing_packet) - 4; |
packet_length = buffer_len(&outgoing_packet) - 4; |
cp = buffer_ptr(&outgoing_packet); |
ucp = (u_char *)buffer_ptr(&outgoing_packet); |
PUT_32BIT(cp, packet_length); |
PUT_32BIT(ucp, packet_length); |
cp[4] = padlen & 0xff; |
ucp[4] = padlen; |
DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen)); |
DBG(debug("send: len %d (includes padlen %d)", packet_length+4, padlen)); |
|
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/* compute MAC over seqnr and packet(length fields, payload, padding) */ |
/* compute MAC over seqnr and packet(length fields, payload, padding) */ |
if (mac && mac->enabled) { |
if (mac && mac->enabled) { |
macbuf = hmac( mac->md, seqnr, |
macbuf = mac_compute(mac, seqnr, |
(unsigned char *) buffer_ptr(&outgoing_packet), |
(u_char *) buffer_ptr(&outgoing_packet), |
buffer_len(&outgoing_packet), |
buffer_len(&outgoing_packet)); |
mac->key, mac->key_len |
|
); |
|
DBG(debug("done calc MAC out #%d", seqnr)); |
DBG(debug("done calc MAC out #%d", seqnr)); |
} |
} |
/* encrypt packet and append to output buffer. */ |
/* encrypt packet and append to output buffer. */ |
buffer_append_space(&output, &cp, buffer_len(&outgoing_packet)); |
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)); |
buffer_len(&outgoing_packet)); |
/* append unencrypted MAC */ |
/* append unencrypted MAC */ |
if (mac && mac->enabled) |
if (mac && mac->enabled) |
|
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log("outgoing seqnr wraps around"); |
log("outgoing seqnr wraps around"); |
buffer_clear(&outgoing_packet); |
buffer_clear(&outgoing_packet); |
|
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if (type == SSH2_MSG_NEWKEYS) { |
if (type == SSH2_MSG_NEWKEYS) |
if (kex==NULL || mac==NULL || enc==NULL || comp==NULL) |
set_newkeys(MODE_OUT); |
fatal("packet_send2: no KEX"); |
|
if (mac->md != NULL) |
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mac->enabled = 1; |
|
DBG(debug("cipher_init send_context")); |
|
cipher_init(&send_context, enc->cipher, |
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enc->key, enc->cipher->key_len, |
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enc->iv, enc->cipher->block_size); |
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clear_enc_keys(enc, kex->we_need); |
|
if (comp->type != 0 && comp->enabled == 0) { |
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comp->enabled = 1; |
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if (! packet_compression) |
|
packet_start_compression(6); |
|
} |
|
} |
|
} |
} |
|
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void |
void |
packet_send() |
packet_send() |
{ |
{ |
if (use_ssh2_packet_format) |
if (compat20) |
packet_send2(); |
packet_send2(); |
else |
else |
packet_send1(); |
packet_send1(); |
|
|
packet_read(int *payload_len_ptr) |
packet_read(int *payload_len_ptr) |
{ |
{ |
int type, len; |
int type, len; |
fd_set set; |
fd_set *setp; |
char buf[8192]; |
char buf[8192]; |
DBG(debug("packet_read()")); |
DBG(debug("packet_read()")); |
|
|
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setp = (fd_set *)xmalloc(howmany(connection_in+1, NFDBITS) * |
|
sizeof(fd_mask)); |
|
|
/* Since we are blocking, ensure that all written packets have been sent. */ |
/* Since we are blocking, ensure that all written packets have been sent. */ |
packet_write_wait(); |
packet_write_wait(); |
|
|
|
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for (;;) { |
for (;;) { |
/* Try to read a packet from the buffer. */ |
/* Try to read a packet from the buffer. */ |
type = packet_read_poll(payload_len_ptr); |
type = packet_read_poll(payload_len_ptr); |
if (!use_ssh2_packet_format && ( |
if (!compat20 && ( |
type == SSH_SMSG_SUCCESS |
type == SSH_SMSG_SUCCESS |
|| type == SSH_SMSG_FAILURE |
|| type == SSH_SMSG_FAILURE |
|| type == SSH_CMSG_EOF |
|| type == SSH_CMSG_EOF |
|| type == SSH_CMSG_EXIT_CONFIRMATION)) |
|| type == SSH_CMSG_EXIT_CONFIRMATION)) |
packet_integrity_check(*payload_len_ptr, 0, type); |
packet_integrity_check(*payload_len_ptr, 0, type); |
/* If we got a packet, return it. */ |
/* If we got a packet, return it. */ |
if (type != SSH_MSG_NONE) |
if (type != SSH_MSG_NONE) { |
|
xfree(setp); |
return type; |
return type; |
|
} |
/* |
/* |
* Otherwise, wait for some data to arrive, add it to the |
* Otherwise, wait for some data to arrive, add it to the |
* buffer, and try again. |
* buffer, and try again. |
*/ |
*/ |
FD_ZERO(&set); |
memset(setp, 0, howmany(connection_in + 1, NFDBITS) * |
FD_SET(connection_in, &set); |
sizeof(fd_mask)); |
|
FD_SET(connection_in, setp); |
|
|
/* Wait for some data to arrive. */ |
/* 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. */ |
/* Read data from the socket. */ |
len = read(connection_in, buf, sizeof(buf)); |
len = read(connection_in, buf, sizeof(buf)); |
|
|
* Check bytes |
* Check bytes |
*/ |
*/ |
|
|
int |
static int |
packet_read_poll1(int *payload_len_ptr) |
packet_read_poll1(int *payload_len_ptr) |
{ |
{ |
unsigned int len, padded_len; |
u_int len, padded_len; |
unsigned char *ucp; |
u_char *ucp, type; |
char buf[8], *cp; |
char *cp; |
unsigned int checksum, stored_checksum; |
u_int checksum, stored_checksum; |
|
|
/* Check if input size is less than minimum packet size. */ |
/* Check if input size is less than minimum packet size. */ |
if (buffer_len(&input) < 4 + 8) |
if (buffer_len(&input) < 4 + 8) |
return SSH_MSG_NONE; |
return SSH_MSG_NONE; |
/* Get length of incoming packet. */ |
/* Get length of incoming packet. */ |
ucp = (unsigned char *) buffer_ptr(&input); |
ucp = (u_char *) buffer_ptr(&input); |
len = GET_32BIT(ucp); |
len = GET_32BIT(ucp); |
if (len < 1 + 2 + 2 || len > 256 * 1024) |
if (len < 1 + 2 + 2 || len > 256 * 1024) |
packet_disconnect("Bad packet length %d.", len); |
packet_disconnect("Bad packet length %d.", len); |
|
|
/* Consume packet length. */ |
/* Consume packet length. */ |
buffer_consume(&input, 4); |
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_clear(&incoming_packet); |
buffer_append_space(&incoming_packet, &cp, padded_len); |
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); |
buffer_consume(&input, padded_len); |
|
|
#ifdef PACKET_DEBUG |
#ifdef PACKET_DEBUG |
|
|
#endif |
#endif |
|
|
/* Compute packet checksum. */ |
/* Compute packet checksum. */ |
checksum = ssh_crc32((unsigned char *) buffer_ptr(&incoming_packet), |
checksum = ssh_crc32((u_char *) buffer_ptr(&incoming_packet), |
buffer_len(&incoming_packet) - 4); |
buffer_len(&incoming_packet) - 4); |
|
|
/* Skip padding. */ |
/* Skip padding. */ |
buffer_consume(&incoming_packet, 8 - len % 8); |
buffer_consume(&incoming_packet, 8 - len % 8); |
|
|
/* Test check bytes. */ |
/* Test check bytes. */ |
|
|
if (len != buffer_len(&incoming_packet)) |
if (len != buffer_len(&incoming_packet)) |
packet_disconnect("packet_read_poll: len %d != buffer_len %d.", |
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); |
stored_checksum = GET_32BIT(ucp); |
if (checksum != stored_checksum) |
if (checksum != stored_checksum) |
packet_disconnect("Corrupted check bytes on input."); |
packet_disconnect("Corrupted check bytes on input."); |
buffer_consume_end(&incoming_packet, 4); |
buffer_consume_end(&incoming_packet, 4); |
|
|
/* If using packet compression, decompress the packet. */ |
|
if (packet_compression) { |
if (packet_compression) { |
buffer_clear(&compression_buffer); |
buffer_clear(&compression_buffer); |
buffer_uncompress(&incoming_packet, &compression_buffer); |
buffer_uncompress(&incoming_packet, &compression_buffer); |
|
|
buffer_append(&incoming_packet, buffer_ptr(&compression_buffer), |
buffer_append(&incoming_packet, buffer_ptr(&compression_buffer), |
buffer_len(&compression_buffer)); |
buffer_len(&compression_buffer)); |
} |
} |
/* Get packet type. */ |
type = buffer_get_char(&incoming_packet); |
buffer_get(&incoming_packet, &buf[0], 1); |
|
|
|
/* Return length of payload (without type field). */ |
|
*payload_len_ptr = buffer_len(&incoming_packet); |
*payload_len_ptr = buffer_len(&incoming_packet); |
|
return type; |
/* Return type. */ |
|
return (unsigned char) buf[0]; |
|
} |
} |
|
|
int |
static int |
packet_read_poll2(int *payload_len_ptr) |
packet_read_poll2(int *payload_len_ptr) |
{ |
{ |
unsigned int padlen, need; |
static u_int32_t seqnr = 0; |
unsigned char buf[8], *macbuf; |
static u_int packet_length = 0; |
unsigned char *ucp; |
u_int padlen, need; |
|
u_char *macbuf, *ucp, type; |
char *cp; |
char *cp; |
static unsigned int packet_length = 0; |
|
static unsigned int seqnr = 0; |
|
int type; |
|
int maclen, block_size; |
int maclen, block_size; |
Enc *enc = NULL; |
Enc *enc = NULL; |
Mac *mac = NULL; |
Mac *mac = NULL; |
Comp *comp = NULL; |
Comp *comp = NULL; |
|
|
if (kex != NULL) { |
if (newkeys[MODE_IN] != NULL) { |
enc = &kex->enc[MODE_IN]; |
enc = &newkeys[MODE_IN]->enc; |
mac = &kex->mac[MODE_IN]; |
mac = &newkeys[MODE_IN]->mac; |
comp = &kex->comp[MODE_IN]; |
comp = &newkeys[MODE_IN]->comp; |
} |
} |
maclen = mac && mac->enabled ? mac->mac_len : 0; |
maclen = mac && mac->enabled ? mac->mac_len : 0; |
block_size = enc ? enc->cipher->block_size : 8; |
block_size = enc ? enc->cipher->block_size : 8; |
|
|
return SSH_MSG_NONE; |
return SSH_MSG_NONE; |
buffer_clear(&incoming_packet); |
buffer_clear(&incoming_packet); |
buffer_append_space(&incoming_packet, &cp, block_size); |
buffer_append_space(&incoming_packet, &cp, block_size); |
packet_decrypt(&receive_context, cp, buffer_ptr(&input), |
cipher_decrypt(&receive_context, cp, buffer_ptr(&input), |
block_size); |
block_size); |
ucp = (unsigned char *) buffer_ptr(&incoming_packet); |
ucp = (u_char *) buffer_ptr(&incoming_packet); |
packet_length = GET_32BIT(ucp); |
packet_length = GET_32BIT(ucp); |
if (packet_length < 1 + 4 || packet_length > 256 * 1024) { |
if (packet_length < 1 + 4 || packet_length > 256 * 1024) { |
buffer_dump(&incoming_packet); |
buffer_dump(&incoming_packet); |
|
|
buffer_dump(&input); |
buffer_dump(&input); |
#endif |
#endif |
buffer_append_space(&incoming_packet, &cp, need); |
buffer_append_space(&incoming_packet, &cp, need); |
packet_decrypt(&receive_context, cp, buffer_ptr(&input), need); |
cipher_decrypt(&receive_context, cp, buffer_ptr(&input), need); |
buffer_consume(&input, need); |
buffer_consume(&input, need); |
/* |
/* |
* compute MAC over seqnr and packet, |
* compute MAC over seqnr and packet, |
* increment sequence number for incoming packet |
* increment sequence number for incoming packet |
*/ |
*/ |
if (mac && mac->enabled) { |
if (mac && mac->enabled) { |
macbuf = hmac( mac->md, seqnr, |
macbuf = mac_compute(mac, seqnr, |
(unsigned char *) buffer_ptr(&incoming_packet), |
(u_char *) buffer_ptr(&incoming_packet), |
buffer_len(&incoming_packet), |
buffer_len(&incoming_packet)); |
mac->key, mac->key_len |
|
); |
|
if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0) |
if (memcmp(macbuf, buffer_ptr(&input), mac->mac_len) != 0) |
packet_disconnect("Corrupted MAC on input."); |
packet_disconnect("Corrupted MAC on input."); |
DBG(debug("MAC #%d ok", seqnr)); |
DBG(debug("MAC #%d ok", seqnr)); |
|
|
|
|
/* get padlen */ |
/* get padlen */ |
cp = buffer_ptr(&incoming_packet) + 4; |
cp = buffer_ptr(&incoming_packet) + 4; |
padlen = *cp & 0xff; |
padlen = (u_char) *cp; |
DBG(debug("input: padlen %d", padlen)); |
DBG(debug("input: padlen %d", padlen)); |
if (padlen < 4) |
if (padlen < 4) |
packet_disconnect("Corrupted padlen %d on input.", padlen); |
packet_disconnect("Corrupted padlen %d on input.", padlen); |
|
|
* get packet type, implies consume. |
* get packet type, implies consume. |
* return length of payload (without type field) |
* return length of payload (without type field) |
*/ |
*/ |
buffer_get(&incoming_packet, (char *)&buf[0], 1); |
type = buffer_get_char(&incoming_packet); |
|
if (type == SSH2_MSG_NEWKEYS) |
|
set_newkeys(MODE_IN); |
*payload_len_ptr = buffer_len(&incoming_packet); |
*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; |
|
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; |
|
if (! packet_compression) |
|
packet_start_compression(6); |
|
} |
|
} |
|
|
|
#ifdef PACKET_DEBUG |
#ifdef PACKET_DEBUG |
fprintf(stderr, "read/plain[%d]:\r\n",type); |
fprintf(stderr, "read/plain[%d]:\r\n", type); |
buffer_dump(&incoming_packet); |
buffer_dump(&incoming_packet); |
#endif |
#endif |
return (unsigned char)type; |
/* reset for next packet */ |
|
packet_length = 0; |
|
return type; |
} |
} |
|
|
int |
int |
packet_read_poll(int *payload_len_ptr) |
packet_read_poll(int *payload_len_ptr) |
{ |
{ |
|
int reason; |
|
u_char type; |
char *msg; |
char *msg; |
for (;;) { |
|
int type = use_ssh2_packet_format ? |
|
packet_read_poll2(payload_len_ptr): |
|
packet_read_poll1(payload_len_ptr); |
|
|
|
if(compat20) { |
for (;;) { |
int reason; |
if (compat20) { |
if (type != 0) |
type = packet_read_poll2(payload_len_ptr); |
|
if (type) |
DBG(debug("received packet type %d", type)); |
DBG(debug("received packet type %d", type)); |
switch(type) { |
switch(type) { |
case SSH2_MSG_IGNORE: |
case SSH2_MSG_IGNORE: |
|
|
case SSH2_MSG_DISCONNECT: |
case SSH2_MSG_DISCONNECT: |
reason = packet_get_int(); |
reason = packet_get_int(); |
msg = packet_get_string(NULL); |
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); |
xfree(msg); |
fatal_cleanup(); |
fatal_cleanup(); |
break; |
break; |
default: |
default: |
return type; |
return type; |
break; |
break; |
} |
} |
} else { |
} else { |
|
type = packet_read_poll1(payload_len_ptr); |
switch(type) { |
switch(type) { |
case SSH_MSG_IGNORE: |
case SSH_MSG_IGNORE: |
break; |
break; |
|
|
break; |
break; |
case SSH_MSG_DISCONNECT: |
case SSH_MSG_DISCONNECT: |
msg = packet_get_string(NULL); |
msg = packet_get_string(NULL); |
log("Received disconnect: %.900s", msg); |
log("Received disconnect from %s: %.400s", get_remote_ipaddr(), |
|
msg); |
fatal_cleanup(); |
fatal_cleanup(); |
xfree(msg); |
xfree(msg); |
break; |
break; |
default: |
default: |
if (type != 0) |
if (type) |
DBG(debug("received packet type %d", type)); |
DBG(debug("received packet type %d", type)); |
return type; |
return type; |
break; |
break; |
} |
} |
} |
} |
} |
} |
} |
} |
|
|
*/ |
*/ |
|
|
void |
void |
packet_process_incoming(const char *buf, unsigned int len) |
packet_process_incoming(const char *buf, u_int len) |
{ |
{ |
buffer_append(&input, buf, len); |
buffer_append(&input, buf, len); |
} |
} |
|
|
/* Returns a character from the packet. */ |
/* Returns a character from the packet. */ |
|
|
unsigned int |
u_int |
packet_get_char() |
packet_get_char() |
{ |
{ |
char ch; |
char ch; |
buffer_get(&incoming_packet, &ch, 1); |
buffer_get(&incoming_packet, &ch, 1); |
return (unsigned char) ch; |
return (u_char) ch; |
} |
} |
|
|
/* Returns an integer from the packet data. */ |
/* Returns an integer from the packet data. */ |
|
|
unsigned int |
u_int |
packet_get_int() |
packet_get_int() |
{ |
{ |
return buffer_get_int(&incoming_packet); |
return buffer_get_int(&incoming_packet); |
|
|
*/ |
*/ |
|
|
char * |
char * |
packet_get_string(unsigned int *length_ptr) |
packet_get_string(u_int *length_ptr) |
{ |
{ |
return buffer_get_string(&incoming_packet, length_ptr); |
return buffer_get_string(&incoming_packet, length_ptr); |
} |
} |
|
|
char buf[1024]; |
char buf[1024]; |
va_list args; |
va_list args; |
|
|
|
if (compat20 && (datafellows & SSH_BUG_DEBUG)) |
|
return; |
|
|
va_start(args, fmt); |
va_start(args, fmt); |
vsnprintf(buf, sizeof(buf), fmt, args); |
vsnprintf(buf, sizeof(buf), fmt, args); |
va_end(args); |
va_end(args); |
|
|
packet_put_cstring(""); |
packet_put_cstring(""); |
} else { |
} else { |
packet_start(SSH_MSG_DISCONNECT); |
packet_start(SSH_MSG_DISCONNECT); |
packet_put_string(buf, strlen(buf)); |
packet_put_cstring(buf); |
} |
} |
packet_send(); |
packet_send(); |
packet_write_wait(); |
packet_write_wait(); |
|
|
/* Stop listening for connections. */ |
/* Stop listening for connections. */ |
channel_stop_listening(); |
channel_close_all(); |
|
|
/* Close the connection. */ |
/* Close the connection. */ |
packet_close(); |
packet_close(); |
|
|
void |
void |
packet_write_wait() |
packet_write_wait() |
{ |
{ |
|
fd_set *setp; |
|
|
|
setp = (fd_set *)xmalloc(howmany(connection_out + 1, NFDBITS) * |
|
sizeof(fd_mask)); |
packet_write_poll(); |
packet_write_poll(); |
while (packet_have_data_to_write()) { |
while (packet_have_data_to_write()) { |
fd_set set; |
memset(setp, 0, howmany(connection_out + 1, NFDBITS) * |
FD_ZERO(&set); |
sizeof(fd_mask)); |
FD_SET(connection_out, &set); |
FD_SET(connection_out, setp); |
select(connection_out + 1, NULL, &set, NULL, NULL); |
while (select(connection_out + 1, NULL, setp, NULL, NULL) == -1 && |
|
(errno == EAGAIN || errno == EINTR)) |
|
; |
packet_write_poll(); |
packet_write_poll(); |
} |
} |
|
xfree(setp); |
} |
} |
|
|
/* Returns true if there is buffered data to write to the connection. */ |
/* Returns true if there is buffered data to write to the connection. */ |
|
|
/* Informs that the current session is interactive. Sets IP flags for that. */ |
/* Informs that the current session is interactive. Sets IP flags for that. */ |
|
|
void |
void |
packet_set_interactive(int interactive, int keepalives) |
packet_set_interactive(int interactive) |
{ |
{ |
|
static int called = 0; |
|
int lowdelay = IPTOS_LOWDELAY; |
|
int throughput = IPTOS_THROUGHPUT; |
int on = 1; |
int on = 1; |
|
|
|
if (called) |
|
return; |
|
called = 1; |
|
|
/* Record that we are in interactive mode. */ |
/* Record that we are in interactive mode. */ |
interactive_mode = interactive; |
interactive_mode = interactive; |
|
|
/* Only set socket options if using a socket. */ |
/* Only set socket options if using a socket. */ |
if (!packet_connection_is_on_socket()) |
if (!packet_connection_is_on_socket()) |
return; |
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) { |
if (interactive) { |
/* |
/* |
* Set IP options for an interactive connection. Use |
* Set IP options for an interactive connection. Use |
* IPTOS_LOWDELAY and TCP_NODELAY. |
* IPTOS_LOWDELAY and TCP_NODELAY. |
*/ |
*/ |
int lowdelay = IPTOS_LOWDELAY; |
if (packet_connection_is_ipv4()) { |
if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &lowdelay, |
if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, |
sizeof(lowdelay)) < 0) |
(void *) &lowdelay, sizeof(lowdelay)) < 0) |
error("setsockopt IPTOS_LOWDELAY: %.100s", strerror(errno)); |
error("setsockopt IPTOS_LOWDELAY: %.100s", |
|
strerror(errno)); |
|
} |
if (setsockopt(connection_in, IPPROTO_TCP, TCP_NODELAY, (void *) &on, |
if (setsockopt(connection_in, IPPROTO_TCP, TCP_NODELAY, (void *) &on, |
sizeof(on)) < 0) |
sizeof(on)) < 0) |
error("setsockopt TCP_NODELAY: %.100s", strerror(errno)); |
error("setsockopt TCP_NODELAY: %.100s", strerror(errno)); |
} else { |
} else if (packet_connection_is_ipv4()) { |
/* |
/* |
* Set IP options for a non-interactive connection. Use |
* Set IP options for a non-interactive connection. Use |
* IPTOS_THROUGHPUT. |
* IPTOS_THROUGHPUT. |
*/ |
*/ |
int throughput = IPTOS_THROUGHPUT; |
|
if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &throughput, |
if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &throughput, |
sizeof(throughput)) < 0) |
sizeof(throughput)) < 0) |
error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno)); |
error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno)); |
|
|
log("packet_set_maxsize: bad size %d", s); |
log("packet_set_maxsize: bad size %d", s); |
return -1; |
return -1; |
} |
} |
log("packet_set_maxsize: setting to %d", s); |
called = 1; |
|
debug("packet_set_maxsize: setting to %d", s); |
max_packet_size = s; |
max_packet_size = s; |
return 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; |
|
} |
} |
} |