ircd-hybrid/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 "common.h"      /* TRUE bleah */
#include "hash.h"        /* add_to_client_hash_table */
#include "s_conf.h"      /* struct AccessItem */
#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:	69
Committed:	Tue Oct 4 16:09:51 2005 UTC (20 years, 10 months ago) by adx
Content type:	text/x-csrc
File size:	14909 byte(s)
Log Message:	- splitted ircd/libio, all headers connected with libio sources have been moved for internal use only. To use libio interface, include "libio.h" (which is already done in "stdinc.h")
#	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 "common.h" /* TRUE bleah */
44			#include "hash.h" /* add_to_client_hash_table */
45			#include "s_conf.h" /* struct AccessItem */
46			#include "s_serv.h" /* server_estab, check_server, my_name_for_link */
47			#include "s_stats.h" /* ServerStats */
48			#include "motd.h"
49
50			static int bogus_host(char *host);
51			static char parse_cryptserv_args(struct Client client_p,
52			char parv[], int parc, char info,
53			char *key);
54
55			static void mr_cryptlink(struct Client , struct Client , int, char **);
56			static void cryptlink_serv(struct Client , struct Client , int, char **);
57			static void cryptlink_auth(struct Client , struct Client , int, char **);
58
59			struct Message cryptlink_msgtab = {
60			"CRYPTLINK", 0, 0, 4, 0, MFLG_SLOW \| MFLG_UNREG, 0,
61			{mr_cryptlink, m_ignore, m_error, m_ignore, m_ignore, m_ignore}
62			};
63
64			struct CryptLinkStruct
65			{
66			const char cmd; / CRYPTLINK <command> to match */
67			void (handler)(); / Function to call */
68			};
69
70			static struct CryptLinkStruct cryptlink_cmd_table[] =
71			{
72			/* command function */
73			{ "AUTH", cryptlink_auth, },
74			{ "SERV", cryptlink_serv, },
75			/* End of table */
76			{ (char )0, (void ()())0, }
77			};
78
79			#ifndef STATIC_MODULES
80			void
81			_modinit(void)
82			{
83			mod_add_cmd(&cryptlink_msgtab);
84			}
85
86			void
87			_moddeinit(void)
88			{
89			mod_del_cmd(&cryptlink_msgtab);
90			}
91
92	knight	31	const char *_version = "$Revision$";
93	adx	30	#endif
94
95
96			/* mr_cryptlink - CRYPTLINK message handler
97			* parv[0] == CRYPTLINK
98			* parv[1] = command (SERV, AUTH)
99			* parv[2] = Parameters specific to each command (parv[1]):
100			* SERV - parc must be >= 5
101			* parv[0] == CRYPTLINK
102			* parv[1] == SERV
103			* parv[2] == server name
104			* parv[3] == keyphrase
105			* parv[4] == :server info (M-line)
106			* AUTH - parc must be >= 4
107			* parv[0] == CRYPTLINK
108			* parv[1] == AUTH
109			* parv[2] == cipher (eg. BF/168)
110			* parv[3] == keyphrase
111			*/
112			static void
113			mr_cryptlink(struct Client client_p, struct Client source_p,
114			int parc, char *parv[])
115			{
116			int i;
117
118			for (i = 0; cryptlink_cmd_table[i].handler; i++)
119			{
120			/* Traverse through the command table */
121			if (!irccmp(cryptlink_cmd_table[i].cmd, parv[1]))
122			{
123			/*
124			* Match found. Time to execute the function
125			*/
126			cryptlink_cmd_table[i].handler(client_p, source_p, parc, parv);
127			}
128			}
129			}
130
131			/*
132			* cryptlink_auth - CRYPTLINK AUTH message handler
133			* parv[1] = secret key
134			*/
135			static void
136			cryptlink_auth(struct Client client_p, struct Client source_p,
137			int parc, char *parv[])
138			{
139			struct EncCapability *ecap;
140			struct ConfItem *conf;
141			struct AccessItem *aconf;
142			int enc_len;
143			int len;
144			unsigned char *enc;
145			unsigned char *key;
146
147			if (parc < 4)
148			{
149			cryptlink_error(client_p, "AUTH", "Invalid params",
150			"CRYPTLINK AUTH - Invalid params");
151			return;
152			}
153
154			if (!IsWaitAuth(client_p))
155			return;
156
157			for (ecap = CipherTable; ecap->name; ecap++)
158			{
159			if ((!irccmp(ecap->name, parv[2])) &&
160			(IsCapableEnc(client_p, ecap->cap)))
161			{
162			client_p->localClient->in_cipher = ecap;
163			break;
164			}
165			}
166
167			if (client_p->localClient->in_cipher == NULL)
168			{
169			cryptlink_error(client_p, "AUTH", "Invalid cipher", "Invalid cipher");
170			return;
171			}
172
173			if (!(enc_len = unbase64_block(&enc, parv[3], strlen(parv[3]))))
174			{
175			cryptlink_error(client_p, "AUTH",
176			"Could not base64 decode response",
177			"Malformed CRYPTLINK AUTH reply");
178			return;
179			}
180
181			if (verify_private_key() == -1)
182			{
183			sendto_realops_flags(UMODE_ALL, L_ADMIN,
184			"verify_private_key() returned -1. Check log for information.");
185			}
186
187			key = MyMalloc(RSA_size(ServerInfo.rsa_private_key));
188			len = RSA_private_decrypt(enc_len, (unsigned char )enc,(unsigned char )key,
189			ServerInfo.rsa_private_key,
190			RSA_PKCS1_PADDING);
191
192			if (len < client_p->localClient->in_cipher->keylen)
193			{
194			report_crypto_errors();
195			if (len < 0)
196			{
197			cryptlink_error(client_p, "AUTH",
198			"Decryption failed",
199			"Malformed CRYPTLINK AUTH reply");
200			}
201			else
202			{
203			cryptlink_error(client_p, "AUTH",
204			"Not enough random data sent",
205			"Malformed CRYPTLINK AUTH reply");
206			}
207			MyFree(enc);
208			MyFree(key);
209			return;
210			}
211
212			if (memcmp(key, client_p->localClient->in_key,
213			client_p->localClient->in_cipher->keylen) != 0)
214			{
215			cryptlink_error(client_p, "AUTH",
216			"Unauthorized server connection attempt",
217			"Malformed CRYPTLINK AUTH reply");
218			return;
219			}
220
221			conf = find_conf_name(&client_p->localClient->confs,
222			client_p->name, SERVER_TYPE);
223
224			if (conf == NULL)
225			{
226			cryptlink_error(client_p, "AUTH",
227			"Lost C-line for server",
228			"Lost C-line");
229			return;
230			}
231
232			aconf = (struct AccessItem *)map_to_conf(conf);
233
234			if (!(client_p->localClient->out_cipher \|\|
235			(client_p->localClient->out_cipher = check_cipher(client_p, aconf))))
236			{
237			cryptlink_error(client_p, "AUTH",
238			"Couldn't find compatible cipher",
239			"Couldn't find compatible cipher");
240			return;
241			}
242
243			/* set hopcount */
244			client_p->hopcount = 1;
245
246			SetCryptIn(client_p);
247			ClearWaitAuth(client_p);
248			server_estab(client_p);
249			}
250
251			/*
252			* cryptlink_serv - CRYPTLINK SERV message handler
253			* parv[0] == CRYPTLINK
254			* parv[1] == SERV
255			* parv[2] == server name
256			* parv[3] == keyphrase
257			* parv[4] == :server info (M-line)
258			*/
259			static void
260			cryptlink_serv(struct Client client_p, struct Client source_p,
261			int parc, char *parv[])
262			{
263			char info[REALLEN + 1];
264			char *name;
265			struct Client *target_p;
266			char *key = client_p->localClient->out_key;
267			unsigned char *b64_key;
268			struct ConfItem *conf;
269			struct AccessItem *aconf;
270			char *encrypted;
271			const char *p;
272			int enc_len;
273
274			/*
275			if (client_p->name[0] != 0)
276			return;
277			*/
278
279			if ((parc < 5) \|\| (*parv[4] == '\0'))
280			{
281			cryptlink_error(client_p, "SERV", "Invalid params",
282			"CRYPTLINK SERV - Invalid params");
283			return;
284			}
285
286			if ((name = parse_cryptserv_args(client_p, parv, parc, info, key)) == NULL)
287			{
288			cryptlink_error(client_p, "SERV", "Invalid params",
289			"CRYPTLINK SERV - Invalid params");
290			return;
291			}
292
293			/* CRYPTLINK SERV support => TS support */
294			client_p->tsinfo = TS_DOESTS;
295
296			if (bogus_host(name))
297			{
298			exit_client(client_p, client_p, "Bogus server name");
299			return;
300			}
301
302			/* Now we just have to call check_server and everything should be
303			* checked for us... -A1kmm. */
304			switch (check_server(name, client_p, CHECK_SERVER_CRYPTLINK))
305			{
306			case -1:
307			if (ConfigFileEntry.warn_no_nline)
308			{
309			cryptlink_error(client_p, "SERV",
310			"Unauthorized server connection attempt: No entry for server",
311			NULL);
312			}
313			exit_client(client_p, client_p, "Invalid server name");
314			return;
315			break;
316			case -2:
317			cryptlink_error(client_p, "SERV",
318			"Unauthorized server connection attempt: CRYPTLINK not "
319			"enabled on remote server",
320			"CRYPTLINK not enabled");
321			return;
322			break;
323			case -3:
324			cryptlink_error(client_p, "SERV",
325			"Unauthorized server connection attempt: Invalid host",
326			"Invalid host");
327			return;
328			break;
329			}
330
331			if ((target_p = find_server(name)))
332			{
333			/*
334			* This link is trying feed me a server that I already have
335			* access through another path -- multiple paths not accepted
336			* currently, kill this link immediately!!
337			*
338			* Rather than KILL the link which introduced it, KILL the
339			* youngest of the two links. -avalon
340			*
341			* Definitely don't do that here. This is from an unregistered
342			* connect - A1kmm.
343			*/
344			cryptlink_error(client_p, "SERV",
345			"Attempt to re-introduce existing server",
346			"Server Exists");
347			return;
348			}
349
350			if (ServerInfo.hub && IsCapable(client_p, CAP_LL))
351			{
352			if (IsCapable(client_p, CAP_HUB))
353			{
354			ClearCap(client_p,CAP_LL);
355			sendto_realops_flags(UMODE_ALL, L_ALL,
356			"*** LazyLinks to a hub from a hub, that's a no-no.");
357			}
358			else
359			{
360			client_p->localClient->serverMask = nextFreeMask();
361
362			if(!client_p->localClient->serverMask)
363			{
364			sendto_realops_flags(UMODE_ALL, L_ALL,
365			"serverMask is full!");
366			/* try and negotiate a non LL connect */
367			ClearCap(client_p,CAP_LL);
368			}
369			}
370			}
371			else if (IsCapable(client_p, CAP_LL))
372			{
373			if (!IsCapable(client_p, CAP_HUB))
374			{
375			ClearCap(client_p,CAP_LL);
376			sendto_realops_flags(UMODE_ALL, L_ALL,
377			"*** LazyLinks to a leaf from a leaf, that's a no-no.");
378			}
379			}
380
381			conf = find_conf_name(&client_p->localClient->confs,
382			name, SERVER_TYPE);
383			if (conf == NULL)
384			{
385			cryptlink_error(client_p, "AUTH",
386			"Lost C-line for server",
387			"Lost C-line" );
388			return;
389			}
390
391			/*
392			* if we are connecting (Handshake), we already have the name from the
393			* connect {} block in client_p->name
394			*/
395			strlcpy(client_p->name, name, sizeof(client_p->name));
396
397			p = info;
398
399			if (!strncmp(info, "(H)", 3))
400			{
401			SetHidden(client_p);
402
403			if ((p = strchr(info, ' ')) != NULL)
404			{
405			p++;
406			if (*p == '\0')
407			p = "(Unknown Location)";
408			}
409			else
410			p = "(Unknown Location)";
411			}
412
413			strlcpy(client_p->info, p, sizeof(client_p->info));
414			client_p->hopcount = 0;
415
416			aconf = (struct AccessItem *)map_to_conf(conf);
417
418			if (!(client_p->localClient->out_cipher \|\|
419			(client_p->localClient->out_cipher = check_cipher(client_p, aconf))))
420			{
421			cryptlink_error(client_p, "AUTH",
422			"Couldn't find compatible cipher",
423			"Couldn't find compatible cipher");
424			return;
425			}
426
427			encrypted = MyMalloc(RSA_size(ServerInfo.rsa_private_key));
428			enc_len = RSA_public_encrypt(client_p->localClient->out_cipher->keylen,
429			(unsigned char *)key,
430			(unsigned char *)encrypted,
431			aconf->rsa_public_key,
432			RSA_PKCS1_PADDING);
433
434			if (enc_len <= 0)
435			{
436			report_crypto_errors();
437			MyFree(encrypted);
438			cryptlink_error(client_p, "AUTH",
439			"Couldn't encrypt data",
440			"Couldn't encrypt data");
441			return;
442			}
443
444			base64_block(&b64_key, encrypted, enc_len);
445
446			MyFree(encrypted);
447
448			if (!IsWaitAuth(client_p))
449			{
450			cryptlink_init(client_p, conf, NULL);
451			}
452
453			sendto_one(client_p, "CRYPTLINK AUTH %s %s",
454			client_p->localClient->out_cipher->name,
455			b64_key);
456
457			/* needed for old servers that can't shove data back into slink */
458			send_queued_write(client_p);
459
460			SetCryptOut(client_p);
461			MyFree(b64_key);
462			}
463
464			/* parse_cryptserv_args()
465			*
466			* inputs - parv parameters
467			* - parc count
468			* - info string (to be filled in by this routine)
469			* - key (to be filled in by this routine)
470			* output - NULL if invalid params, server name otherwise
471			* side effects - parv[2] is trimmed to HOSTLEN size if needed.
472			*/
473			static char *
474			parse_cryptserv_args(struct Client client_p, char parv[],
475			int parc, char info, char key)
476			{
477			char *name;
478			unsigned char tmp, out;
479			int len;
480			int decoded_len;
481
482			info[0] = '\0';
483
484			name = parv[2];
485
486			/* parv[2] contains encrypted auth data */
487			if (!(decoded_len = unbase64_block(&tmp, parv[3],
488			strlen(parv[3]))))
489			{
490			cryptlink_error(client_p, "SERV",
491			"Couldn't base64 decode data",
492			NULL);
493			return(NULL);
494			}
495
496			if (verify_private_key() == -1)
497			{
498			sendto_realops_flags(UMODE_ALL, L_ADMIN,
499			"verify_private_key() returned -1. Check log for information.");
500			}
501
502			if (ServerInfo.rsa_private_key == NULL)
503			{
504			cryptlink_error(client_p, "SERV", "No local private key found", NULL);
505			return(NULL);
506			}
507
508			out = MyMalloc(RSA_size(ServerInfo.rsa_private_key));
509			len = RSA_private_decrypt(decoded_len, tmp, out,
510			ServerInfo.rsa_private_key,
511			RSA_PKCS1_PADDING);
512
513			MyFree(tmp);
514
515			if (len < CIPHERKEYLEN)
516			{
517			report_crypto_errors();
518			if (len < 0)
519			{
520			cryptlink_error(client_p, "AUTH", "Decryption failed", NULL);
521			}
522			else
523			{
524			cryptlink_error(client_p, "AUTH", "Not enough random data sent", NULL);
525			}
526			MyFree(out);
527			return(NULL);
528			}
529
530			memcpy(key, out, CIPHERKEYLEN);
531			MyFree(out);
532
533			strlcpy(info, parv[4], REALLEN + 1);
534
535			if (strlen(name) > HOSTLEN)
536			name[HOSTLEN] = '\0';
537
538			return(name);
539			}
540
541			/* bogus_host()
542			*
543			* inputs - hostname
544			* output - 1 if a bogus hostname input, 0 if its valid
545			* side effects - none
546			*/
547			static int
548			bogus_host(char *host)
549			{
550			unsigned int length = 0;
551			unsigned int dots = 0;
552			char *s = host;
553
554			for (; *s; s++)
555			{
556			if (!IsServChar(*s))
557			return(1);
558
559			++length;
560
561			if ('.' == *s)
562			++dots;
563			}
564
565			return(!dots \|\| length > HOSTLEN);
566			}