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Diff for /src/usr.bin/ssh/packet.c between version 1.61 and 1.61.2.4

version 1.61, 2001/04/05 10:42:51 version 1.61.2.4, 2002/03/09 00:20:44
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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 "mac.h"  #include "mac.h"
 #include "log.h"  #include "log.h"
 #include "canohost.h"  #include "canohost.h"
   #include "misc.h"
   
 #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;
   
 /*  
  * 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. */  /* Protocol flags for the remote side. */
 static u_int remote_protocol_flags = 0;  static u_int remote_protocol_flags = 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;
   
 /* True if SSH2 packet format is used */  
 int use_ssh2_packet_format = 0;  
   
 /* Session key information for Encryption and MAC */  /* Session key information for Encryption and MAC */
 Newkeys *newkeys[MODE_MAX];  Newkeys *newkeys[MODE_MAX];
   
 void  /* roundup current message to extra_pad bytes */
 packet_set_ssh2_format(void)  static u_char extra_pad = 0;
 {  
         DBG(debug("use_ssh2_packet_format"));  
         use_ssh2_packet_format = 1;  
         newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL;  
 }  
   
 /*  /*
  * Sets the descriptors used for communication.  Disables encryption until   * Sets the descriptors used for communication.  Disables encryption until
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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, "", 0, NULL, 0, CIPHER_ENCRYPT);
         cipher_init(&send_context, none, (u_char *) "", 0, NULL, 0);          cipher_init(&receive_context, none, "", 0, NULL, 0, CIPHER_DECRYPT);
         cipher_init(&receive_context, none, (u_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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 /* Returns 1 if remote host is connected via socket, 0 if not. */  /* Returns 1 if remote host is connected via socket, 0 if not. */
   
 int  int
 packet_connection_is_on_socket()  packet_connection_is_on_socket(void)
 {  {
         struct sockaddr_storage from, to;          struct sockaddr_storage from, to;
         socklen_t fromlen, tolen;          socklen_t fromlen, tolen;
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 /* returns 1 if connection is via ipv4 */  /* returns 1 if connection is via ipv4 */
   
 int  int
 packet_connection_is_ipv4()  packet_connection_is_ipv4(void)
 {  {
         struct sockaddr_storage to;          struct sockaddr_storage to;
         socklen_t tolen = sizeof(to);          socklen_t tolen = sizeof(to);
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 /* Sets the connection into non-blocking mode. */  /* Sets the connection into non-blocking mode. */
   
 void  void
 packet_set_nonblocking()  packet_set_nonblocking(void)
 {  {
         /* Set the socket into non-blocking mode. */          /* Set the socket into non-blocking mode. */
         if (fcntl(connection_in, F_SETFL, O_NONBLOCK) < 0)          if (fcntl(connection_in, F_SETFL, O_NONBLOCK) < 0)
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 /* Returns the socket used for reading. */  /* Returns the socket used for reading. */
   
 int  int
 packet_get_connection_in()  packet_get_connection_in(void)
 {  {
         return connection_in;          return connection_in;
 }  }
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 /* Returns the descriptor used for writing. */  /* Returns the descriptor used for writing. */
   
 int  int
 packet_get_connection_out()  packet_get_connection_out(void)
 {  {
         return connection_out;          return connection_out;
 }  }
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 /* Closes the connection and clears and frees internal data structures. */  /* Closes the connection and clears and frees internal data structures. */
   
 void  void
 packet_close()  packet_close(void)
 {  {
         if (!initialized)          if (!initialized)
                 return;                  return;
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                 buffer_free(&compression_buffer);                  buffer_free(&compression_buffer);
                 buffer_compress_uninit();                  buffer_compress_uninit();
         }          }
           cipher_cleanup(&send_context);
           cipher_cleanup(&receive_context);
 }  }
   
 /* Sets remote side protocol flags. */  /* Sets remote side protocol flags. */
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 packet_set_protocol_flags(u_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);  
 }  }
   
 /* Returns the remote protocol flags set earlier by the above function. */  /* Returns the remote protocol flags set earlier by the above function. */
   
 u_int  u_int
 packet_get_protocol_flags()  packet_get_protocol_flags(void)
 {  {
         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.
  */   */
   
 void  static void
 packet_init_compression()  packet_init_compression(void)
 {  {
         if (compression_buffer_ready == 1)          if (compression_buffer_ready == 1)
                 return;                  return;
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 void  void
 packet_start_compression(int level)  packet_start_compression(int level)
 {  {
         if (packet_compression && !use_ssh2_packet_format)          if (packet_compression && !compat20)
                 fatal("Compression already enabled.");                  fatal("Compression already enabled.");
         packet_compression = 1;          packet_compression = 1;
         packet_init_compression();          packet_init_compression();
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 }  }
   
 /*  /*
  * 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,  
     u_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 *context, void *dest, void *src, u_int bytes)  
 {  
         /*  
          * Cryptographic attack detector for ssh - Modifications for packet.c  
          * (C)1998 CORE-SDI, Buenos Aires Argentina Ariel Futoransky(futo@core-sdi.com)  
          */  
         if (!compat20 &&  
             context->cipher->number != SSH_CIPHER_NONE &&  
             detect_attack(src, bytes, NULL) == DEATTACK_DETECTED)  
                 packet_disconnect("crc32 compensation attack: network attack detected");  
   
         cipher_decrypt(context, dest, src, bytes);  
 }  
   
 /*  
  * 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.
  */   */
   
 void  void
 packet_set_encryption_key(const u_char *key, u_int keylen,  packet_set_encryption_key(const u_char *key, u_int keylen,
     int number)      int number)
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                 fatal("packet_set_encryption_key: unknown cipher number %d", number);                  fatal("packet_set_encryption_key: unknown cipher number %d", number);
         if (keylen < 20)          if (keylen < 20)
                 fatal("packet_set_encryption_key: keylen too small: %d", 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, CIPHER_ENCRYPT);
         cipher_init(&send_context, cipher, key, keylen, NULL, 0);          cipher_init(&receive_context, cipher, key, keylen, NULL, 0, CIPHER_DECRYPT);
 }  }
   
 /* Starts constructing a packet to send. */  /* Start constructing a packet to send. */
   
 void  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);          buffer_clear(&outgoing_packet);
         memset(buf, 0, 8);          buffer_append(&outgoing_packet, buf, len);
         buf[8] = type;  
         buffer_append(&outgoing_packet, buf, 9);  
 }  }
   
   /* Append payload. */
 void  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);  
 }  
   
 /* Appends a character to the packet data. */  
   
 void  
 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);
 }  }
   
 /* Appends an integer to the packet data. */  
   
 void  void
 packet_put_int(u_int value)  packet_put_int(u_int value)
 {  {
         buffer_put_int(&outgoing_packet, value);          buffer_put_int(&outgoing_packet, value);
 }  }
   
 /* Appends a string to packet data. */  
   
 void  void
 packet_put_string(const char *buf, u_int len)  packet_put_string(const void *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);
 }  }
   
 void  void
 packet_put_raw(const char *buf, u_int len)  packet_put_raw(const void *buf, u_int len)
 {  {
         buffer_append(&outgoing_packet, buf, len);          buffer_append(&outgoing_packet, buf, len);
 }  }
   
   
 /* Appends an arbitrary precision integer to packet data. */  
   
 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.
  */   */
   
 void  static void
 packet_send1(void)  packet_send1(void)
 {  {
         char buf[8], *cp;          u_char buf[8], *cp;
         int i, padding, len;          int i, padding, len;
         u_int checksum;          u_int checksum;
         u_int32_t rand = 0;          u_int32_t rand = 0;
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                 buffer_compress(&outgoing_packet, &compression_buffer);                  buffer_compress(&outgoing_packet, &compression_buffer);
                 buffer_clear(&outgoing_packet);                  buffer_clear(&outgoing_packet);
                 buffer_append(&outgoing_packet, buffer_ptr(&compression_buffer),                  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). */          /* Compute packet length without padding (add checksum, remove padding). */
         len = buffer_len(&outgoing_packet) + 4 - 8;          len = buffer_len(&outgoing_packet) + 4 - 8;
   
         /* 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.plaintext) {
                 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);
   
         /* Add check bytes. */          /* Add check bytes. */
         checksum = ssh_crc32((u_char *) buffer_ptr(&outgoing_packet),          checksum = ssh_crc32(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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         /* Append to output. */          /* Append to output. */
         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));          cp = buffer_append_space(&output, buffer_len(&outgoing_packet));
         packet_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),          cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet),
                        buffer_len(&outgoing_packet));              buffer_len(&outgoing_packet));
   
 #ifdef PACKET_DEBUG  #ifdef PACKET_DEBUG
         fprintf(stderr, "encrypted: ");          fprintf(stderr, "encrypted: ");
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          */           */
 }  }
   
 void  static void
 set_newkeys(int mode)  set_newkeys(int mode)
 {  {
         Enc *enc;          Enc *enc;
         Mac *mac;          Mac *mac;
         Comp *comp;          Comp *comp;
         CipherContext *cc;          CipherContext *cc;
           int encrypt;
   
         debug("newkeys: mode %d", mode);          debug("newkeys: mode %d", mode);
   
         cc = (mode == MODE_OUT) ? &send_context : &receive_context;          if (mode == MODE_OUT) {
                   cc = &send_context;
                   encrypt = CIPHER_ENCRYPT;
           } else {
                   cc = &receive_context;
                   encrypt = CIPHER_DECRYPT;
           }
         if (newkeys[mode] != NULL) {          if (newkeys[mode] != NULL) {
                 debug("newkeys: rekeying");                  debug("newkeys: rekeying");
                 /* todo: free old keys, reset compression/cipher-ctxt; */                  cipher_cleanup(cc);
                 memset(cc, 0, sizeof(*cc));  
                 enc  = &newkeys[mode]->enc;                  enc  = &newkeys[mode]->enc;
                 mac  = &newkeys[mode]->mac;                  mac  = &newkeys[mode]->mac;
                 comp = &newkeys[mode]->comp;                  comp = &newkeys[mode]->comp;
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         if (mac->md != NULL)          if (mac->md != NULL)
                 mac->enabled = 1;                  mac->enabled = 1;
         DBG(debug("cipher_init_context: %d", mode));          DBG(debug("cipher_init_context: %d", mode));
         cipher_init(cc, enc->cipher, enc->key, enc->cipher->key_len,          cipher_init(cc, enc->cipher, enc->key, enc->key_len,
             enc->iv, enc->cipher->block_size);              enc->iv, enc->block_size, encrypt);
         memset(enc->iv,  0, enc->cipher->block_size);          memset(enc->iv,  0, enc->block_size);
         memset(enc->key, 0, enc->cipher->key_len);          memset(enc->key, 0, enc->key_len);
         if (comp->type != 0 && comp->enabled == 0) {          if (comp->type != 0 && comp->enabled == 0) {
                 packet_init_compression();                  packet_init_compression();
                 if (mode == MODE_OUT)                  if (mode == MODE_OUT)
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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(void)  packet_send2(void)
 {  {
         static u_int32_t seqnr = 0;          static u_int32_t seqnr = 0;
         u_char *macbuf = NULL;          u_char type, *cp, *macbuf = NULL;
         char *cp;          u_char padlen, pad;
         u_int packet_length = 0;          u_int packet_length = 0;
         u_int i, padlen, len;          u_int i, len;
         u_int32_t rand = 0;          u_int32_t rand = 0;
         int type;  
         Enc *enc   = NULL;          Enc *enc   = NULL;
         Mac *mac   = NULL;          Mac *mac   = NULL;
         Comp *comp = NULL;          Comp *comp = NULL;
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                 mac  = &newkeys[MODE_OUT]->mac;                  mac  = &newkeys[MODE_OUT]->mac;
                 comp = &newkeys[MODE_OUT]->comp;                  comp = &newkeys[MODE_OUT]->comp;
         }          }
         block_size = enc ? enc->cipher->block_size : 8;          block_size = enc ? enc->block_size : 8;
   
         cp = buffer_ptr(&outgoing_packet);          cp = buffer_ptr(&outgoing_packet);
         type = cp[5] & 0xff;          type = cp[5];
   
 #ifdef PACKET_DEBUG  #ifdef PACKET_DEBUG
         fprintf(stderr, "plain:     ");          fprintf(stderr, "plain:     ");
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         padlen = block_size - (len % block_size);          padlen = block_size - (len % block_size);
         if (padlen < 4)          if (padlen < 4)
                 padlen += block_size;                  padlen += block_size;
         buffer_append_space(&outgoing_packet, &cp, padlen);          if (extra_pad) {
         if (enc && enc->cipher->number != SSH_CIPHER_NONE) {                  /* 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 && !send_context.plaintext) {
                 /* random padding */                  /* random padding */
                 for (i = 0; i < padlen; i++) {                  for (i = 0; i < padlen; i++) {
                         if (i % 4 == 0)                          if (i % 4 == 0)
Line 635 
Line 571 
         packet_length = buffer_len(&outgoing_packet) - 4;          packet_length = buffer_len(&outgoing_packet) - 4;
         cp = buffer_ptr(&outgoing_packet);          cp = buffer_ptr(&outgoing_packet);
         PUT_32BIT(cp, packet_length);          PUT_32BIT(cp, packet_length);
         cp[4] = padlen & 0xff;          cp[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));
   
         /* 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 = mac_compute(mac, seqnr,                  macbuf = mac_compute(mac, seqnr,
                     (u_char *) buffer_ptr(&outgoing_packet),                      buffer_ptr(&outgoing_packet),
                     buffer_len(&outgoing_packet));                      buffer_len(&outgoing_packet));
                 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));          cp = buffer_append_space(&output, buffer_len(&outgoing_packet));
         packet_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),          cipher_crypt(&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)
Line 666 
Line 602 
 }  }
   
 void  void
 packet_send()  packet_send(void)
 {  {
         if (use_ssh2_packet_format)          if (compat20)
                 packet_send2();                  packet_send2();
         else          else
                 packet_send1();                  packet_send1();
Line 682 
Line 618 
  */   */
   
 int  int
 packet_read(int *payload_len_ptr)  packet_read_seqnr(u_int32_t *seqnr_p)
 {  {
         int type, len;          int type, len;
         fd_set *setp;          fd_set *setp;
Line 698 
Line 634 
         /* Stay in the loop until we have received a complete packet. */          /* Stay in the loop until we have received a complete packet. */
         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_seqnr(seqnr_p);
                 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_check_eom();
                 /* 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);                          xfree(setp);
Line 737 
Line 673 
         /* NOTREACHED */          /* NOTREACHED */
 }  }
   
   int
   packet_read(void)
   {
           return packet_read_seqnr(NULL);
   }
   
 /*  /*
  * Waits until a packet has been received, verifies that its type matches   * 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.   * that given, and gives a fatal error and exits if there is a mismatch.
  */   */
   
 void  void
 packet_read_expect(int *payload_len_ptr, int expected_type)  packet_read_expect(int expected_type)
 {  {
         int type;          int type;
   
         type = packet_read(payload_len_ptr);          type = packet_read();
         if (type != expected_type)          if (type != expected_type)
                 packet_disconnect("Protocol error: expected packet type %d, got %d",                  packet_disconnect("Protocol error: expected packet type %d, got %d",
                     expected_type, type);                      expected_type, type);
Line 760 
Line 702 
  * SSH_MSG_DISCONNECT is handled specially here.  Also,   * SSH_MSG_DISCONNECT is handled specially here.  Also,
  * SSH_MSG_IGNORE messages are skipped by this function and are never returned   * SSH_MSG_IGNORE messages are skipped by this function and are never returned
  * to higher levels.   * to higher levels.
  *  
  * The returned payload_len does include space consumed by:  
  *      Packet length  
  *      Padding  
  *      Packet type  
  *      Check bytes  
  */   */
   
 int  static int
 packet_read_poll1(int *payload_len_ptr)  packet_read_poll1(void)
 {  {
         u_int len, padded_len;          u_int len, padded_len;
         u_char *ucp;          u_char *cp, type;
         char buf[8], *cp;  
         u_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 = (u_char *) buffer_ptr(&input);          cp = buffer_ptr(&input);
         len = GET_32BIT(ucp);          len = GET_32BIT(cp);
         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);
         padded_len = (len + 8) & ~7;          padded_len = (len + 8) & ~7;
Line 795 
Line 730 
         /* 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.plaintext &&
               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);          cp = buffer_append_space(&incoming_packet, padded_len);
         packet_decrypt(&receive_context, cp, buffer_ptr(&input), padded_len);          cipher_crypt(&receive_context, cp, buffer_ptr(&input), padded_len);
   
         buffer_consume(&input, padded_len);          buffer_consume(&input, padded_len);
   
 #ifdef PACKET_DEBUG  #ifdef PACKET_DEBUG
Line 807 
Line 752 
 #endif  #endif
   
         /* Compute packet checksum. */          /* Compute packet checksum. */
         checksum = ssh_crc32((u_char *) buffer_ptr(&incoming_packet),          checksum = ssh_crc32(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_poll1: len %d != buffer_len %d.",
                     len, buffer_len(&incoming_packet));                      len, buffer_len(&incoming_packet));
   
         ucp = (u_char *) buffer_ptr(&incoming_packet) + len - 4;          cp = (u_char *)buffer_ptr(&incoming_packet) + len - 4;
         stored_checksum = GET_32BIT(ucp);          stored_checksum = GET_32BIT(cp);
         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);
Line 833 
Line 776 
                 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 type;
   
         /* Return length of payload (without type field). */  
         *payload_len_ptr = buffer_len(&incoming_packet);  
   
         /* Return type. */  
         return (u_char) buf[0];  
 }  }
   
 int  static int
 packet_read_poll2(int *payload_len_ptr)  packet_read_poll2(u_int32_t *seqnr_p)
 {  {
         static u_int32_t seqnr = 0;          static u_int32_t seqnr = 0;
         static u_int packet_length = 0;          static u_int packet_length = 0;
         u_int padlen, need;          u_int padlen, need;
         u_char buf[8], *macbuf;          u_char *macbuf, *cp, type;
         u_char *ucp;  
         char *cp;  
         int type;  
         int maclen, block_size;          int maclen, block_size;
         Enc *enc   = NULL;          Enc *enc   = NULL;
         Mac *mac   = NULL;          Mac *mac   = NULL;
Line 864 
Line 798 
                 comp = &newkeys[MODE_IN]->comp;                  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->block_size : 8;
   
         if (packet_length == 0) {          if (packet_length == 0) {
                 /*                  /*
Line 874 
Line 808 
                 if (buffer_len(&input) < block_size)                  if (buffer_len(&input) < block_size)
                         return SSH_MSG_NONE;                          return SSH_MSG_NONE;
                 buffer_clear(&incoming_packet);                  buffer_clear(&incoming_packet);
                 buffer_append_space(&incoming_packet, &cp, block_size);                  cp = buffer_append_space(&incoming_packet, block_size);
                 packet_decrypt(&receive_context, cp, buffer_ptr(&input),                  cipher_crypt(&receive_context, cp, buffer_ptr(&input),
                     block_size);                      block_size);
                 ucp = (u_char *) buffer_ptr(&incoming_packet);                  cp = buffer_ptr(&incoming_packet);
                 packet_length = GET_32BIT(ucp);                  packet_length = GET_32BIT(cp);
                 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);
                         packet_disconnect("Bad packet length %d.", packet_length);                          packet_disconnect("Bad packet length %d.", packet_length);
Line 903 
Line 837 
         fprintf(stderr, "read_poll enc/full: ");          fprintf(stderr, "read_poll enc/full: ");
         buffer_dump(&input);          buffer_dump(&input);
 #endif  #endif
         buffer_append_space(&incoming_packet, &cp, need);          cp = buffer_append_space(&incoming_packet, need);
         packet_decrypt(&receive_context, cp, buffer_ptr(&input), need);          cipher_crypt(&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,
Line 912 
Line 846 
          */           */
         if (mac && mac->enabled) {          if (mac && mac->enabled) {
                 macbuf = mac_compute(mac, seqnr,                  macbuf = mac_compute(mac, seqnr,
                     (u_char *) buffer_ptr(&incoming_packet),                      buffer_ptr(&incoming_packet),
                     buffer_len(&incoming_packet));                      buffer_len(&incoming_packet));
                 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));
                 buffer_consume(&input, mac->mac_len);                  buffer_consume(&input, mac->mac_len);
         }          }
           if (seqnr_p != NULL)
                   *seqnr_p = seqnr;
         if (++seqnr == 0)          if (++seqnr == 0)
                 log("incoming seqnr wraps around");                  log("incoming seqnr wraps around");
   
         /* get padlen */          /* get padlen */
         cp = buffer_ptr(&incoming_packet) + 4;          cp = buffer_ptr(&incoming_packet);
         padlen = *cp & 0xff;          padlen = cp[4];
         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);
Line 946 
Line 882 
          * 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);
         *payload_len_ptr = buffer_len(&incoming_packet);  
   
         /* reset for next packet */  
         packet_length = 0;  
   
         /* extract packet type */  
         type = (u_char)buf[0];  
   
         if (type == SSH2_MSG_NEWKEYS)          if (type == SSH2_MSG_NEWKEYS)
                 set_newkeys(MODE_IN);                  set_newkeys(MODE_IN);
   
 #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 (u_char)type;          /* reset for next packet */
           packet_length = 0;
           return type;
 }  }
   
 int  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;          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(seqnr_p);
                           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:
                                 break;                                  break;
                         case SSH2_MSG_DEBUG:                          case SSH2_MSG_DEBUG:
Line 997 
Line 925 
                                 xfree(msg);                                  xfree(msg);
                                 fatal_cleanup();                                  fatal_cleanup();
                                 break;                                  break;
                           case SSH2_MSG_UNIMPLEMENTED:
                                   seqnr = packet_get_int();
                                   debug("Received SSH2_MSG_UNIMPLEMENTED for %d", seqnr);
                                   break;
                         default:                          default:
                                 return type;                                  return type;
                                 break;                                  break;
                         }                          }
                 } else {                  } else {
                         switch(type) {                          type = packet_read_poll1();
                           switch (type) {
                         case SSH_MSG_IGNORE:                          case SSH_MSG_IGNORE:
                                 break;                                  break;
                         case SSH_MSG_DEBUG:                          case SSH_MSG_DEBUG:
Line 1018 
Line 951 
                                 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;
Line 1027 
Line 960 
         }          }
 }  }
   
   int
   packet_read_poll(void)
   {
           return packet_read_poll_seqnr(NULL);
   }
   
 /*  /*
  * Buffers the given amount of input characters.  This is intended to be used   * Buffers the given amount of input characters.  This is intended to be used
  * together with packet_read_poll.   * together with packet_read_poll.
Line 1041 
Line 980 
 /* Returns a character from the packet. */  /* Returns a character from the packet. */
   
 u_int  u_int
 packet_get_char()  packet_get_char(void)
 {  {
         char ch;          char ch;
         buffer_get(&incoming_packet, &ch, 1);          buffer_get(&incoming_packet, &ch, 1);
Line 1051 
Line 990 
 /* Returns an integer from the packet data. */  /* Returns an integer from the packet data. */
   
 u_int  u_int
 packet_get_int()  packet_get_int(void)
 {  {
         return buffer_get_int(&incoming_packet);          return buffer_get_int(&incoming_packet);
 }  }
Line 1062 
Line 1001 
  */   */
   
 void  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  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)  packet_get_raw(int *length_ptr)
 {  {
         int bytes = buffer_len(&incoming_packet);          int bytes = buffer_len(&incoming_packet);
Line 1095 
Line 1034 
  * integer into which the length of the string is stored.   * integer into which the length of the string is stored.
  */   */
   
 char *  void *
 packet_get_string(u_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);
Line 1169 
Line 1108 
                 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();
Line 1188 
Line 1127 
 /* Checks if there is any buffered output, and tries to write some of the output. */  /* Checks if there is any buffered output, and tries to write some of the output. */
   
 void  void
 packet_write_poll()  packet_write_poll(void)
 {  {
         int len = buffer_len(&output);          int len = buffer_len(&output);
         if (len > 0) {          if (len > 0) {
Line 1209 
Line 1148 
  */   */
   
 void  void
 packet_write_wait()  packet_write_wait(void)
 {  {
         fd_set *setp;          fd_set *setp;
   
Line 1231 
Line 1170 
 /* Returns true if there is buffered data to write to the connection. */  /* Returns true if there is buffered data to write to the connection. */
   
 int  int
 packet_have_data_to_write()  packet_have_data_to_write(void)
 {  {
         return buffer_len(&output) != 0;          return buffer_len(&output) != 0;
 }  }
Line 1239 
Line 1178 
 /* Returns true if there is not too much data to write to the connection. */  /* Returns true if there is not too much data to write to the connection. */
   
 int  int
 packet_not_very_much_data_to_write()  packet_not_very_much_data_to_write(void)
 {  {
         if (interactive_mode)          if (interactive_mode)
                 return buffer_len(&output) < 16384;                  return buffer_len(&output) < 16384;
Line 1255 
Line 1194 
         static int called = 0;          static int called = 0;
         int lowdelay = IPTOS_LOWDELAY;          int lowdelay = IPTOS_LOWDELAY;
         int throughput = IPTOS_THROUGHPUT;          int throughput = IPTOS_THROUGHPUT;
         int on = 1;  
   
         if (called)          if (called)
                 return;                  return;
Line 1277 
Line 1215 
                  */                   */
                 if (packet_connection_is_ipv4()) {                  if (packet_connection_is_ipv4()) {
                         if (setsockopt(connection_in, IPPROTO_IP, IP_TOS,                          if (setsockopt(connection_in, IPPROTO_IP, IP_TOS,
                             (void *) &lowdelay, sizeof(lowdelay)) < 0)                              &lowdelay, sizeof(lowdelay)) < 0)
                                 error("setsockopt IPTOS_LOWDELAY: %.100s",                                  error("setsockopt IPTOS_LOWDELAY: %.100s",
                                     strerror(errno));                                      strerror(errno));
                 }                  }
                 if (setsockopt(connection_in, IPPROTO_TCP, TCP_NODELAY, (void *) &on,                  set_nodelay(connection_in);
                     sizeof(on)) < 0)  
                         error("setsockopt TCP_NODELAY: %.100s", strerror(errno));  
         } else if (packet_connection_is_ipv4()) {          } 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.
                  */                   */
                 if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, (void *) &throughput,                  if (setsockopt(connection_in, IPPROTO_IP, IP_TOS, &throughput,
                     sizeof(throughput)) < 0)                      sizeof(throughput)) < 0)
                         error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno));                          error("setsockopt IPTOS_THROUGHPUT: %.100s", strerror(errno));
         }          }
Line 1298 
Line 1234 
 /* Returns true if the current connection is interactive. */  /* Returns true if the current connection is interactive. */
   
 int  int
 packet_is_interactive()  packet_is_interactive(void)
 {  {
         return interactive_mode;          return interactive_mode;
 }  }
Line 1316 
Line 1252 
                 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;
 }  }
   
   /* roundup current message to pad bytes */
   void
   packet_add_padding(u_char pad)
   {
           extra_pad = pad;
   }
   
 /*  /*
  * 9.2.  Ignored Data Message   * 9.2.  Ignored Data Message
  *   *
Line 1332 
Line 1276 
  * required to send them. This message can be used as an additional   * required to send them. This message can be used as an additional
  * protection measure against advanced traffic analysis techniques.   * protection measure against advanced traffic analysis techniques.
  */   */
 /* size of current + ignore message should be n*sumlen bytes (w/o mac) */  
 void  void
 packet_inject_ignore(int sumlen)  
 {  
         int blocksize, padlen, have, need, nb, mini, nbytes;  
         Enc *enc = NULL;  
   
         if (use_ssh2_packet_format == 0)  
                 return;  
   
         have = buffer_len(&outgoing_packet);  
         debug2("packet_inject_ignore: current %d", have);  
         if (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)  packet_send_ignore(int nbytes)
 {  {
         u_int32_t rand = 0;          u_int32_t rand = 0;
Line 1375 
Line 1284 
   
         packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE);          packet_start(compat20 ? SSH2_MSG_IGNORE : SSH_MSG_IGNORE);
         packet_put_int(nbytes);          packet_put_int(nbytes);
         for(i = 0; i < nbytes; i++) {          for (i = 0; i < nbytes; i++) {
                 if (i % 4 == 0)                  if (i % 4 == 0)
                         rand = arc4random();                          rand = arc4random();
                 packet_put_char(rand & 0xff);                  packet_put_char(rand & 0xff);
Legend:
Removed from v.1.61  
changed lines
  Added in v.1.61.2.4