ircd-hybrid-7.2/modules/m_cryptlink.c

/*
 *  ircd-hybrid: an advanced Internet Relay Chat Daemon(ircd).
 *  m_cryptlink.c: Used to negotiate an encrypted link.
 *
 *  Copyright (C) 2002 by the past and present ircd coders, and others.
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
 *  USA
 *
 *  $Id$
 */

/*
 * CRYPTLINK protocol.
 *
 * Please see doc/cryptlink.txt for a description of this protocol.
 *
 */

#include "stdinc.h"
#include "handlers.h"
#include "client.h"      /* client struct */
#include "ircd.h"        /* me */
#include "modules.h"
#include "numeric.h"     /* ERR_xxx */
#include "send.h"        /* sendto_one */
#include <openssl/rsa.h> /* rsa.h is implicit when building this */
#include "rsa.h"
#include "msg.h"
#include "parse.h"
#include "irc_string.h"  /* strncpy_irc */
#include "tools.h"
#include "memory.h"
#include "common.h"      /* TRUE bleah */
#include "event.h"
#include "hash.h"        /* add_to_client_hash_table */
#include "list.h"        /* make_server */
#include "s_conf.h"      /* struct AccessItem */
#include "s_log.h"       /* log level defines */
#include "s_serv.h"      /* server_estab, check_server, my_name_for_link */
#include "s_stats.h"     /* ServerStats */
#include "motd.h"

static int bogus_host(char *host);
static char *parse_cryptserv_args(struct Client *client_p,
                                  char *parv[], int parc, char *info,
                                  char *key);

static void mr_cryptlink(struct Client *, struct Client *, int, char **);
static void cryptlink_serv(struct Client *, struct Client *, int, char **);
static void cryptlink_auth(struct Client *, struct Client *, int, char **);

struct Message cryptlink_msgtab = {
  "CRYPTLINK", 0, 0, 4, 0, MFLG_SLOW | MFLG_UNREG, 0,
  {mr_cryptlink, m_ignore, m_error, m_ignore, m_ignore, m_ignore}
};

struct CryptLinkStruct
{
  const char *cmd;   /* CRYPTLINK <command> to match */
  void (*handler)(); /* Function to call             */
};

static struct CryptLinkStruct cryptlink_cmd_table[] =
{
  /* command    function        */
  { "AUTH",     cryptlink_auth, },
  { "SERV",     cryptlink_serv, },
  /* End of table */
  { (char *)0,  (void (*)())0,  }
};

#ifndef STATIC_MODULES
void 
_modinit(void)
{
  mod_add_cmd(&cryptlink_msgtab);
}

void
_moddeinit(void)
{
  mod_del_cmd(&cryptlink_msgtab);
}

const char *_version = "$Revision$";
#endif


/* mr_cryptlink - CRYPTLINK message handler
 *      parv[0] == CRYPTLINK
 *      parv[1] = command (SERV, AUTH)
 *      parv[2] = Parameters specific to each command (parv[1]):
 *                   SERV - parc must be >= 5
 *                          parv[0] == CRYPTLINK
 *                          parv[1] == SERV
 *                          parv[2] == server name
 *                          parv[3] == keyphrase
 *                          parv[4] == :server info (M-line)
 *                   AUTH - parc must be >= 4
 *                          parv[0] == CRYPTLINK
 *                          parv[1] == AUTH
 *                          parv[2] == cipher (eg. BF/168)
 *                          parv[3] == keyphrase
 */
static void
mr_cryptlink(struct Client *client_p, struct Client *source_p,
             int parc, char *parv[])
{
  int i;

  for (i = 0; cryptlink_cmd_table[i].handler; i++)
  {
    /* Traverse through the command table */
    if (!irccmp(cryptlink_cmd_table[i].cmd, parv[1]))
    {
      /*
       * Match found.  Time to execute the function
       */
      cryptlink_cmd_table[i].handler(client_p, source_p, parc, parv);
    }
  }
}

/*
 * cryptlink_auth - CRYPTLINK AUTH message handler
 *        parv[1] = secret key
 */
static void
cryptlink_auth(struct Client *client_p, struct Client *source_p,
               int parc, char *parv[])
{
  struct EncCapability *ecap;
  struct ConfItem *conf;
  struct AccessItem *aconf;
  int   enc_len;
  int   len;
  unsigned char *enc;
  unsigned char *key;

  if (parc < 4)
  {
    cryptlink_error(client_p, "AUTH", "Invalid params",
                    "CRYPTLINK AUTH - Invalid params");
    return;
  }

  if (!IsWaitAuth(client_p))
    return;

  for (ecap = CipherTable; ecap->name; ecap++)
  {
    if ((!irccmp(ecap->name, parv[2])) &&
        (IsCapableEnc(client_p, ecap->cap)))
    {
      client_p->localClient->in_cipher = ecap;
      break;
    }
  }

  if (client_p->localClient->in_cipher == NULL)
  {
    cryptlink_error(client_p, "AUTH", "Invalid cipher", "Invalid cipher");
    return;
  }

  if (!(enc_len = unbase64_block(&enc, parv[3], strlen(parv[3]))))
  {
    cryptlink_error(client_p, "AUTH",
                    "Could not base64 decode response",
                    "Malformed CRYPTLINK AUTH reply");
    return;
  }

  if (verify_private_key() == -1)
  {
    sendto_realops_flags(UMODE_ALL, L_ADMIN,
      "verify_private_key() returned -1.  Check log for information.");
  }

  key = MyMalloc(RSA_size(ServerInfo.rsa_private_key));
  len = RSA_private_decrypt(enc_len, (unsigned char *)enc,(unsigned char *)key,
                            ServerInfo.rsa_private_key,
                            RSA_PKCS1_PADDING);

  if (len < client_p->localClient->in_cipher->keylen)
  {
    report_crypto_errors();
    if (len < 0)
    {
      cryptlink_error(client_p, "AUTH",
                      "Decryption failed",
                      "Malformed CRYPTLINK AUTH reply");
    }
    else
    {
      cryptlink_error(client_p, "AUTH",
                      "Not enough random data sent",
                      "Malformed CRYPTLINK AUTH reply");
    }
    MyFree(enc);
    MyFree(key);
    return;
  }

  if (memcmp(key, client_p->localClient->in_key,
             client_p->localClient->in_cipher->keylen) != 0)
  {
    cryptlink_error(client_p, "AUTH",
                    "Unauthorized server connection attempt",
                    "Malformed CRYPTLINK AUTH reply");
    return;
  }

  conf = find_conf_name(&client_p->localClient->confs,
                         client_p->name, SERVER_TYPE);

  if (conf == NULL)
  {
    cryptlink_error(client_p, "AUTH",
                    "Lost C-line for server",
                    "Lost C-line");
    return;
  }

  aconf = (struct AccessItem *)map_to_conf(conf);

  if (!(client_p->localClient->out_cipher ||
      (client_p->localClient->out_cipher = check_cipher(client_p, aconf))))
  {
    cryptlink_error(client_p, "AUTH",
                    "Couldn't find compatible cipher",
                    "Couldn't find compatible cipher");
    return;
  }

  /* set hopcount */
  client_p->hopcount = 1;

  SetCryptIn(client_p);
  ClearWaitAuth(client_p);
  server_estab(client_p);
}

/*
 * cryptlink_serv - CRYPTLINK SERV message handler
 *        parv[0] == CRYPTLINK
 *        parv[1] == SERV
 *        parv[2] == server name
 *        parv[3] == keyphrase
 *        parv[4] == :server info (M-line)
 */
static void
cryptlink_serv(struct Client *client_p, struct Client *source_p,
               int parc, char *parv[])
{
  char info[REALLEN + 1];
  char *name;
  struct Client *target_p;
  char *key = client_p->localClient->out_key;
  unsigned char *b64_key;
  struct ConfItem *conf;
  struct AccessItem *aconf;
  char *encrypted;
  const char *p;
  int enc_len;

  /*
  if (client_p->name[0] != 0)
  return;
  */

  if ((parc < 5) || (*parv[4] == '\0'))
  {
    cryptlink_error(client_p, "SERV", "Invalid params",
                    "CRYPTLINK SERV - Invalid params");
    return;
  }

  if ((name = parse_cryptserv_args(client_p, parv, parc, info, key)) == NULL)
  {
    cryptlink_error(client_p, "SERV", "Invalid params",
                    "CRYPTLINK SERV - Invalid params");
    return;
  }

  /* CRYPTLINK SERV support => TS support */
  client_p->tsinfo = TS_DOESTS;

  if (bogus_host(name))
  {
    exit_client(client_p, client_p, "Bogus server name");
    return;
  }

  /* Now we just have to call check_server and everything should be
   * checked for us... -A1kmm. */
  switch (check_server(name, client_p, CHECK_SERVER_CRYPTLINK))
  {
    case -1:
      if (ConfigFileEntry.warn_no_nline)
      {
        cryptlink_error(client_p, "SERV",
          "Unauthorized server connection attempt: No entry for server",
          NULL);
      }
      exit_client(client_p, client_p, "Invalid server name");
      return;
      break;
    case -2:
      cryptlink_error(client_p, "SERV",
        "Unauthorized server connection attempt: CRYPTLINK not "
                                      "enabled on remote server",
        "CRYPTLINK not enabled");
      return;
      break;
    case -3:
      cryptlink_error(client_p, "SERV",
        "Unauthorized server connection attempt: Invalid host",
        "Invalid host");
      return;
      break;
  }

  if ((target_p = find_server(name)))
  {
    /*
     * This link is trying feed me a server that I already have
     * access through another path -- multiple paths not accepted
     * currently, kill this link immediately!!
     *
     * Rather than KILL the link which introduced it, KILL the
     * youngest of the two links. -avalon
     *
     * Definitely don't do that here. This is from an unregistered
     * connect - A1kmm.
     */
    cryptlink_error(client_p, "SERV",
                    "Attempt to re-introduce existing server",
                    "Server Exists");
    return;
  }

  if (ServerInfo.hub && IsCapable(client_p, CAP_LL))
  {
      if (IsCapable(client_p, CAP_HUB))
      {
          ClearCap(client_p,CAP_LL);
          sendto_realops_flags(UMODE_ALL, L_ALL,
               "*** LazyLinks to a hub from a hub, that's a no-no.");
      }
      else
      {
          client_p->localClient->serverMask = nextFreeMask();

          if(!client_p->localClient->serverMask)
          {
              sendto_realops_flags(UMODE_ALL, L_ALL,
                                   "serverMask is full!");
              /* try and negotiate a non LL connect */
              ClearCap(client_p,CAP_LL);
          }
      }
  }
  else if (IsCapable(client_p, CAP_LL))
  {
      if (!IsCapable(client_p, CAP_HUB))
      {
        ClearCap(client_p,CAP_LL);
        sendto_realops_flags(UMODE_ALL, L_ALL,
          "*** LazyLinks to a leaf from a leaf, that's a no-no.");
      }
  }

  conf = find_conf_name(&client_p->localClient->confs,
                        name, SERVER_TYPE);
  if (conf == NULL)
  {
    cryptlink_error(client_p, "AUTH",
                    "Lost C-line for server",
                    "Lost C-line" );
    return;
  }

  /*
   * if we are connecting (Handshake), we already have the name from the
   * connect {} block in client_p->name
   */
  strlcpy(client_p->name, name, sizeof(client_p->name));

  p = info;

  if (!strncmp(info, "(H)", 3))
  {
    SetHidden(client_p);

    if ((p = strchr(info, ' ')) != NULL)
    {
      p++;
      if (*p == '\0')
        p = "(Unknown Location)";
    }
    else
      p = "(Unknown Location)";
  }

  strlcpy(client_p->info, p, sizeof(client_p->info));
  client_p->hopcount = 0;

  aconf = (struct AccessItem *)map_to_conf(conf);

  if (!(client_p->localClient->out_cipher ||
      (client_p->localClient->out_cipher = check_cipher(client_p, aconf))))
  {
    cryptlink_error(client_p, "AUTH",
                    "Couldn't find compatible cipher",
                    "Couldn't find compatible cipher");
    return;
  }

  encrypted = MyMalloc(RSA_size(ServerInfo.rsa_private_key));
  enc_len   = RSA_public_encrypt(client_p->localClient->out_cipher->keylen,
                               (unsigned char *)key,
                               (unsigned char *)encrypted,
                               aconf->rsa_public_key,
                               RSA_PKCS1_PADDING);

  if (enc_len <= 0)
  {
    report_crypto_errors();
    MyFree(encrypted);
    cryptlink_error(client_p, "AUTH",
                    "Couldn't encrypt data",
                    "Couldn't encrypt data");
    return;
  }

  base64_block(&b64_key, encrypted, enc_len);

  MyFree(encrypted);

  if (!IsWaitAuth(client_p))
  {
    cryptlink_init(client_p, conf, NULL);
  }

  sendto_one(client_p, "CRYPTLINK AUTH %s %s",
             client_p->localClient->out_cipher->name,
             b64_key);

  /* needed for old servers that can't shove data back into slink */
  send_queued_write(client_p);

  SetCryptOut(client_p);
  MyFree(b64_key);
}

/* parse_cryptserv_args()
 *
 * inputs       - parv parameters
 *              - parc count
 *              - info string (to be filled in by this routine)
 *              - key (to be filled in by this routine)
 * output       - NULL if invalid params, server name otherwise
 * side effects - parv[2] is trimmed to HOSTLEN size if needed.
 */
static char *
parse_cryptserv_args(struct Client *client_p, char *parv[],
                     int parc, char *info, char *key)
{
  char *name;
  unsigned char *tmp, *out;
  int len;
  int decoded_len;

  info[0] = '\0';

  name = parv[2];

  /* parv[2] contains encrypted auth data */
  if (!(decoded_len = unbase64_block(&tmp, parv[3],
                                     strlen(parv[3]))))
  {
    cryptlink_error(client_p, "SERV",
                    "Couldn't base64 decode data",
                    NULL);
    return(NULL);
  }

  if (verify_private_key() == -1)
  {
    sendto_realops_flags(UMODE_ALL, L_ADMIN,
      "verify_private_key() returned -1.  Check log for information.");
  }

  if (ServerInfo.rsa_private_key == NULL)
  {
    cryptlink_error(client_p, "SERV", "No local private key found", NULL);
    return(NULL);
  }

  out = MyMalloc(RSA_size(ServerInfo.rsa_private_key));
  len = RSA_private_decrypt(decoded_len, tmp, out,
                            ServerInfo.rsa_private_key,
                            RSA_PKCS1_PADDING);

  MyFree(tmp);

  if (len < CIPHERKEYLEN)
  {
    report_crypto_errors();
    if (len < 0)
    {
      cryptlink_error(client_p, "AUTH", "Decryption failed", NULL);
    }
    else
    {
      cryptlink_error(client_p, "AUTH", "Not enough random data sent", NULL);
    }
    MyFree(out);
    return(NULL);
  }

  memcpy(key, out, CIPHERKEYLEN);
  MyFree(out);

  strlcpy(info, parv[4], REALLEN + 1);

  if (strlen(name) > HOSTLEN)
    name[HOSTLEN] = '\0';

  return(name);
}

/* bogus_host()
 *
 * inputs       - hostname
 * output       - 1 if a bogus hostname input, 0 if its valid
 * side effects - none
 */
static int
bogus_host(char *host)
{
  unsigned int length = 0;
  unsigned int dots   = 0;
  char *s = host;

  for (; *s; s++)
  {
    if (!IsServChar(*s))
      return(1);

    ++length;

    if ('.' == *s)
      ++dots;
  }

  return(!dots || length > HOSTLEN);
}
Revision:	33
Committed:	Sun Oct 2 20:50:00 2005 UTC (19 years, 10 months ago) by knight
Content type:	text/x-csrc
Original Path:	*ircd-hybrid/modules/m_cryptlink.c*
File size:	15102 byte(s)
Log Message:	- svn:keywords
#	User	Rev	Content
1	adx	30	/*
2			* ircd-hybrid: an advanced Internet Relay Chat Daemon(ircd).
3			* m_cryptlink.c: Used to negotiate an encrypted link.
4			*
5			* Copyright (C) 2002 by the past and present ircd coders, and others.
6			*
7			* This program is free software; you can redistribute it and/or modify
8			* it under the terms of the GNU General Public License as published by
9			* the Free Software Foundation; either version 2 of the License, or
10			* (at your option) any later version.
11			*
12			* This program is distributed in the hope that it will be useful,
13			* but WITHOUT ANY WARRANTY; without even the implied warranty of
14			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15			* GNU General Public License for more details.
16			*
17			* You should have received a copy of the GNU General Public License
18			* along with this program; if not, write to the Free Software
19			* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
20			* USA
21			*
22	knight	31	* $Id$
23	adx	30	*/
24
25			/*
26			* CRYPTLINK protocol.
27			*
28			* Please see doc/cryptlink.txt for a description of this protocol.
29			*
30			*/
31
32			#include "stdinc.h"
33			#include "handlers.h"
34			#include "client.h" /* client struct */
35			#include "ircd.h" /* me */
36			#include "modules.h"
37			#include "numeric.h" /* ERR_xxx */
38			#include "send.h" /* sendto_one */
39			#include <openssl/rsa.h> /* rsa.h is implicit when building this */
40			#include "rsa.h"
41			#include "msg.h"
42			#include "parse.h"
43			#include "irc_string.h" /* strncpy_irc */
44			#include "tools.h"
45			#include "memory.h"
46			#include "common.h" /* TRUE bleah */
47			#include "event.h"
48			#include "hash.h" /* add_to_client_hash_table */
49			#include "list.h" /* make_server */
50			#include "s_conf.h" /* struct AccessItem */
51			#include "s_log.h" /* log level defines */
52			#include "s_serv.h" /* server_estab, check_server, my_name_for_link */
53			#include "s_stats.h" /* ServerStats */
54			#include "motd.h"
55
56			static int bogus_host(char *host);
57			static char parse_cryptserv_args(struct Client client_p,
58			char parv[], int parc, char info,
59			char *key);
60
61			static void mr_cryptlink(struct Client , struct Client , int, char **);
62			static void cryptlink_serv(struct Client , struct Client , int, char **);
63			static void cryptlink_auth(struct Client , struct Client , int, char **);
64
65			struct Message cryptlink_msgtab = {
66			"CRYPTLINK", 0, 0, 4, 0, MFLG_SLOW \| MFLG_UNREG, 0,
67			{mr_cryptlink, m_ignore, m_error, m_ignore, m_ignore, m_ignore}
68			};
69
70			struct CryptLinkStruct
71			{
72			const char cmd; / CRYPTLINK <command> to match */
73			void (handler)(); / Function to call */
74			};
75
76			static struct CryptLinkStruct cryptlink_cmd_table[] =
77			{
78			/* command function */
79			{ "AUTH", cryptlink_auth, },
80			{ "SERV", cryptlink_serv, },
81			/* End of table */
82			{ (char )0, (void ()())0, }
83			};
84
85			#ifndef STATIC_MODULES
86			void
87			_modinit(void)
88			{
89			mod_add_cmd(&cryptlink_msgtab);
90			}
91
92			void
93			_moddeinit(void)
94			{
95			mod_del_cmd(&cryptlink_msgtab);
96			}
97
98	knight	31	const char *_version = "$Revision$";
99	adx	30	#endif
100
101
102			/* mr_cryptlink - CRYPTLINK message handler
103			* parv[0] == CRYPTLINK
104			* parv[1] = command (SERV, AUTH)
105			* parv[2] = Parameters specific to each command (parv[1]):
106			* SERV - parc must be >= 5
107			* parv[0] == CRYPTLINK
108			* parv[1] == SERV
109			* parv[2] == server name
110			* parv[3] == keyphrase
111			* parv[4] == :server info (M-line)
112			* AUTH - parc must be >= 4
113			* parv[0] == CRYPTLINK
114			* parv[1] == AUTH
115			* parv[2] == cipher (eg. BF/168)
116			* parv[3] == keyphrase
117			*/
118			static void
119			mr_cryptlink(struct Client client_p, struct Client source_p,
120			int parc, char *parv[])
121			{
122			int i;
123
124			for (i = 0; cryptlink_cmd_table[i].handler; i++)
125			{
126			/* Traverse through the command table */
127			if (!irccmp(cryptlink_cmd_table[i].cmd, parv[1]))
128			{
129			/*
130			* Match found. Time to execute the function
131			*/
132			cryptlink_cmd_table[i].handler(client_p, source_p, parc, parv);
133			}
134			}
135			}
136
137			/*
138			* cryptlink_auth - CRYPTLINK AUTH message handler
139			* parv[1] = secret key
140			*/
141			static void
142			cryptlink_auth(struct Client client_p, struct Client source_p,
143			int parc, char *parv[])
144			{
145			struct EncCapability *ecap;
146			struct ConfItem *conf;
147			struct AccessItem *aconf;
148			int enc_len;
149			int len;
150			unsigned char *enc;
151			unsigned char *key;
152
153			if (parc < 4)
154			{
155			cryptlink_error(client_p, "AUTH", "Invalid params",
156			"CRYPTLINK AUTH - Invalid params");
157			return;
158			}
159
160			if (!IsWaitAuth(client_p))
161			return;
162
163			for (ecap = CipherTable; ecap->name; ecap++)
164			{
165			if ((!irccmp(ecap->name, parv[2])) &&
166			(IsCapableEnc(client_p, ecap->cap)))
167			{
168			client_p->localClient->in_cipher = ecap;
169			break;
170			}
171			}
172
173			if (client_p->localClient->in_cipher == NULL)
174			{
175			cryptlink_error(client_p, "AUTH", "Invalid cipher", "Invalid cipher");
176			return;
177			}
178
179			if (!(enc_len = unbase64_block(&enc, parv[3], strlen(parv[3]))))
180			{
181			cryptlink_error(client_p, "AUTH",
182			"Could not base64 decode response",
183			"Malformed CRYPTLINK AUTH reply");
184			return;
185			}
186
187			if (verify_private_key() == -1)
188			{
189			sendto_realops_flags(UMODE_ALL, L_ADMIN,
190			"verify_private_key() returned -1. Check log for information.");
191			}
192
193			key = MyMalloc(RSA_size(ServerInfo.rsa_private_key));
194			len = RSA_private_decrypt(enc_len, (unsigned char )enc,(unsigned char )key,
195			ServerInfo.rsa_private_key,
196			RSA_PKCS1_PADDING);
197
198			if (len < client_p->localClient->in_cipher->keylen)
199			{
200			report_crypto_errors();
201			if (len < 0)
202			{
203			cryptlink_error(client_p, "AUTH",
204			"Decryption failed",
205			"Malformed CRYPTLINK AUTH reply");
206			}
207			else
208			{
209			cryptlink_error(client_p, "AUTH",
210			"Not enough random data sent",
211			"Malformed CRYPTLINK AUTH reply");
212			}
213			MyFree(enc);
214			MyFree(key);
215			return;
216			}
217
218			if (memcmp(key, client_p->localClient->in_key,
219			client_p->localClient->in_cipher->keylen) != 0)
220			{
221			cryptlink_error(client_p, "AUTH",
222			"Unauthorized server connection attempt",
223			"Malformed CRYPTLINK AUTH reply");
224			return;
225			}
226
227			conf = find_conf_name(&client_p->localClient->confs,
228			client_p->name, SERVER_TYPE);
229
230			if (conf == NULL)
231			{
232			cryptlink_error(client_p, "AUTH",
233			"Lost C-line for server",
234			"Lost C-line");
235			return;
236			}
237
238			aconf = (struct AccessItem *)map_to_conf(conf);
239
240			if (!(client_p->localClient->out_cipher \|\|
241			(client_p->localClient->out_cipher = check_cipher(client_p, aconf))))
242			{
243			cryptlink_error(client_p, "AUTH",
244			"Couldn't find compatible cipher",
245			"Couldn't find compatible cipher");
246			return;
247			}
248
249			/* set hopcount */
250			client_p->hopcount = 1;
251
252			SetCryptIn(client_p);
253			ClearWaitAuth(client_p);
254			server_estab(client_p);
255			}
256
257			/*
258			* cryptlink_serv - CRYPTLINK SERV message handler
259			* parv[0] == CRYPTLINK
260			* parv[1] == SERV
261			* parv[2] == server name
262			* parv[3] == keyphrase
263			* parv[4] == :server info (M-line)
264			*/
265			static void
266			cryptlink_serv(struct Client client_p, struct Client source_p,
267			int parc, char *parv[])
268			{
269			char info[REALLEN + 1];
270			char *name;
271			struct Client *target_p;
272			char *key = client_p->localClient->out_key;
273			unsigned char *b64_key;
274			struct ConfItem *conf;
275			struct AccessItem *aconf;
276			char *encrypted;
277			const char *p;
278			int enc_len;
279
280			/*
281			if (client_p->name[0] != 0)
282			return;
283			*/
284
285			if ((parc < 5) \|\| (*parv[4] == '\0'))
286			{
287			cryptlink_error(client_p, "SERV", "Invalid params",
288			"CRYPTLINK SERV - Invalid params");
289			return;
290			}
291
292			if ((name = parse_cryptserv_args(client_p, parv, parc, info, key)) == NULL)
293			{
294			cryptlink_error(client_p, "SERV", "Invalid params",
295			"CRYPTLINK SERV - Invalid params");
296			return;
297			}
298
299			/* CRYPTLINK SERV support => TS support */
300			client_p->tsinfo = TS_DOESTS;
301
302			if (bogus_host(name))
303			{
304			exit_client(client_p, client_p, "Bogus server name");
305			return;
306			}
307
308			/* Now we just have to call check_server and everything should be
309			* checked for us... -A1kmm. */
310			switch (check_server(name, client_p, CHECK_SERVER_CRYPTLINK))
311			{
312			case -1:
313			if (ConfigFileEntry.warn_no_nline)
314			{
315			cryptlink_error(client_p, "SERV",
316			"Unauthorized server connection attempt: No entry for server",
317			NULL);
318			}
319			exit_client(client_p, client_p, "Invalid server name");
320			return;
321			break;
322			case -2:
323			cryptlink_error(client_p, "SERV",
324			"Unauthorized server connection attempt: CRYPTLINK not "
325			"enabled on remote server",
326			"CRYPTLINK not enabled");
327			return;
328			break;
329			case -3:
330			cryptlink_error(client_p, "SERV",
331			"Unauthorized server connection attempt: Invalid host",
332			"Invalid host");
333			return;
334			break;
335			}
336
337			if ((target_p = find_server(name)))
338			{
339			/*
340			* This link is trying feed me a server that I already have
341			* access through another path -- multiple paths not accepted
342			* currently, kill this link immediately!!
343			*
344			* Rather than KILL the link which introduced it, KILL the
345			* youngest of the two links. -avalon
346			*
347			* Definitely don't do that here. This is from an unregistered
348			* connect - A1kmm.
349			*/
350			cryptlink_error(client_p, "SERV",
351			"Attempt to re-introduce existing server",
352			"Server Exists");
353			return;
354			}
355
356			if (ServerInfo.hub && IsCapable(client_p, CAP_LL))
357			{
358			if (IsCapable(client_p, CAP_HUB))
359			{
360			ClearCap(client_p,CAP_LL);
361			sendto_realops_flags(UMODE_ALL, L_ALL,
362			"*** LazyLinks to a hub from a hub, that's a no-no.");
363			}
364			else
365			{
366			client_p->localClient->serverMask = nextFreeMask();
367
368			if(!client_p->localClient->serverMask)
369			{
370			sendto_realops_flags(UMODE_ALL, L_ALL,
371			"serverMask is full!");
372			/* try and negotiate a non LL connect */
373			ClearCap(client_p,CAP_LL);
374			}
375			}
376			}
377			else if (IsCapable(client_p, CAP_LL))
378			{
379			if (!IsCapable(client_p, CAP_HUB))
380			{
381			ClearCap(client_p,CAP_LL);
382			sendto_realops_flags(UMODE_ALL, L_ALL,
383			"*** LazyLinks to a leaf from a leaf, that's a no-no.");
384			}
385			}
386
387			conf = find_conf_name(&client_p->localClient->confs,
388			name, SERVER_TYPE);
389			if (conf == NULL)
390			{
391			cryptlink_error(client_p, "AUTH",
392			"Lost C-line for server",
393			"Lost C-line" );
394			return;
395			}
396
397			/*
398			* if we are connecting (Handshake), we already have the name from the
399			* connect {} block in client_p->name
400			*/
401			strlcpy(client_p->name, name, sizeof(client_p->name));
402
403			p = info;
404
405			if (!strncmp(info, "(H)", 3))
406			{
407			SetHidden(client_p);
408
409			if ((p = strchr(info, ' ')) != NULL)
410			{
411			p++;
412			if (*p == '\0')
413			p = "(Unknown Location)";
414			}
415			else
416			p = "(Unknown Location)";
417			}
418
419			strlcpy(client_p->info, p, sizeof(client_p->info));
420			client_p->hopcount = 0;
421
422			aconf = (struct AccessItem *)map_to_conf(conf);
423
424			if (!(client_p->localClient->out_cipher \|\|
425			(client_p->localClient->out_cipher = check_cipher(client_p, aconf))))
426			{
427			cryptlink_error(client_p, "AUTH",
428			"Couldn't find compatible cipher",
429			"Couldn't find compatible cipher");
430			return;
431			}
432
433			encrypted = MyMalloc(RSA_size(ServerInfo.rsa_private_key));
434			enc_len = RSA_public_encrypt(client_p->localClient->out_cipher->keylen,
435			(unsigned char *)key,
436			(unsigned char *)encrypted,
437			aconf->rsa_public_key,
438			RSA_PKCS1_PADDING);
439
440			if (enc_len <= 0)
441			{
442			report_crypto_errors();
443			MyFree(encrypted);
444			cryptlink_error(client_p, "AUTH",
445			"Couldn't encrypt data",
446			"Couldn't encrypt data");
447			return;
448			}
449
450			base64_block(&b64_key, encrypted, enc_len);
451
452			MyFree(encrypted);
453
454			if (!IsWaitAuth(client_p))
455			{
456			cryptlink_init(client_p, conf, NULL);
457			}
458
459			sendto_one(client_p, "CRYPTLINK AUTH %s %s",
460			client_p->localClient->out_cipher->name,
461			b64_key);
462
463			/* needed for old servers that can't shove data back into slink */
464			send_queued_write(client_p);
465
466			SetCryptOut(client_p);
467			MyFree(b64_key);
468			}
469
470			/* parse_cryptserv_args()
471			*
472			* inputs - parv parameters
473			* - parc count
474			* - info string (to be filled in by this routine)
475			* - key (to be filled in by this routine)
476			* output - NULL if invalid params, server name otherwise
477			* side effects - parv[2] is trimmed to HOSTLEN size if needed.
478			*/
479			static char *
480			parse_cryptserv_args(struct Client client_p, char parv[],
481			int parc, char info, char key)
482			{
483			char *name;
484			unsigned char tmp, out;
485			int len;
486			int decoded_len;
487
488			info[0] = '\0';
489
490			name = parv[2];
491
492			/* parv[2] contains encrypted auth data */
493			if (!(decoded_len = unbase64_block(&tmp, parv[3],
494			strlen(parv[3]))))
495			{
496			cryptlink_error(client_p, "SERV",
497			"Couldn't base64 decode data",
498			NULL);
499			return(NULL);
500			}
501
502			if (verify_private_key() == -1)
503			{
504			sendto_realops_flags(UMODE_ALL, L_ADMIN,
505			"verify_private_key() returned -1. Check log for information.");
506			}
507
508			if (ServerInfo.rsa_private_key == NULL)
509			{
510			cryptlink_error(client_p, "SERV", "No local private key found", NULL);
511			return(NULL);
512			}
513
514			out = MyMalloc(RSA_size(ServerInfo.rsa_private_key));
515			len = RSA_private_decrypt(decoded_len, tmp, out,
516			ServerInfo.rsa_private_key,
517			RSA_PKCS1_PADDING);
518
519			MyFree(tmp);
520
521			if (len < CIPHERKEYLEN)
522			{
523			report_crypto_errors();
524			if (len < 0)
525			{
526			cryptlink_error(client_p, "AUTH", "Decryption failed", NULL);
527			}
528			else
529			{
530			cryptlink_error(client_p, "AUTH", "Not enough random data sent", NULL);
531			}
532			MyFree(out);
533			return(NULL);
534			}
535
536			memcpy(key, out, CIPHERKEYLEN);
537			MyFree(out);
538
539			strlcpy(info, parv[4], REALLEN + 1);
540
541			if (strlen(name) > HOSTLEN)
542			name[HOSTLEN] = '\0';
543
544			return(name);
545			}
546
547			/* bogus_host()
548			*
549			* inputs - hostname
550			* output - 1 if a bogus hostname input, 0 if its valid
551			* side effects - none
552			*/
553			static int
554			bogus_host(char *host)
555			{
556			unsigned int length = 0;
557			unsigned int dots = 0;
558			char *s = host;
559
560			for (; *s; s++)
561			{
562			if (!IsServChar(*s))
563			return(1);
564
565			++length;
566
567			if ('.' == *s)
568			++dots;
569			}
570
571			return(!dots \|\| length > HOSTLEN);
572			}