ircd-hybrid-7.3/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"
#ifdef HAVE_LIBCRYPTO

#include "list.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 "memory.h"
#include "common.h"      /* TRUE bleah */
#include "event.h"
#include "hash.h"        /* add_to_client_hash_table */
#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 "motd.h"

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, rfc1459_command_send_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 */
  { NULL,       NULL,   }
};

void 
_modinit(void)
{
  mod_add_cmd(&cryptlink_msgtab);
}

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

const char *_version = "$Revision$";

/* 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 (!valid_servname(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;
  }

  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);
}
#endif
Revision:	1121
Committed:	Sun Jan 9 11:03:03 2011 UTC (15 years, 6 months ago) by michael
Content type:	text/x-csrc
File size:	13692 byte(s)
Log Message:	- removed all instances of STATIC_MODULES since we don't have static modules anymore - removed m_mkpasswd module from contrib
#	Content
1	/*
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	* $Id$
23	*/
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	#ifdef HAVE_LIBCRYPTO
34
35	#include "list.h"
36	#include "handlers.h"
37	#include "client.h" /* client struct */
38	#include "ircd.h" /* me */
39	#include "modules.h"
40	#include "numeric.h" /* ERR_xxx */
41	#include "send.h" /* sendto_one */
42	#include <openssl/rsa.h> /* rsa.h is implicit when building this */
43	#include "rsa.h"
44	#include "msg.h"
45	#include "parse.h"
46	#include "irc_string.h" /* strncpy_irc */
47	#include "memory.h"
48	#include "common.h" /* TRUE bleah */
49	#include "event.h"
50	#include "hash.h" /* add_to_client_hash_table */
51	#include "s_conf.h" /* struct AccessItem */
52	#include "s_log.h" /* log level defines */
53	#include "s_serv.h" /* server_estab, check_server, my_name_for_link */
54	#include "motd.h"
55
56	static char parse_cryptserv_args(struct Client client_p,
57	char parv[], int parc, char info,
58	char *key);
59
60	static void mr_cryptlink(struct Client , struct Client , int, char **);
61	static void cryptlink_serv(struct Client , struct Client , int, char **);
62	static void cryptlink_auth(struct Client , struct Client , int, char **);
63
64	struct Message cryptlink_msgtab = {
65	"CRYPTLINK", 0, 0, 4, 0, MFLG_SLOW \| MFLG_UNREG, 0,
66	{mr_cryptlink, m_ignore, rfc1459_command_send_error, m_ignore, m_ignore, m_ignore}
67	};
68
69	struct CryptLinkStruct
70	{
71	const char cmd; / CRYPTLINK <command> to match */
72	void (handler)(); / Function to call */
73	};
74
75	static struct CryptLinkStruct cryptlink_cmd_table[] =
76	{
77	/* command function */
78	{ "AUTH", cryptlink_auth, },
79	{ "SERV", cryptlink_serv, },
80	/* End of table */
81	{ NULL, NULL, }
82	};
83
84	void
85	_modinit(void)
86	{
87	mod_add_cmd(&cryptlink_msgtab);
88	}
89
90	void
91	_moddeinit(void)
92	{
93	mod_del_cmd(&cryptlink_msgtab);
94	}
95
96	const char *_version = "$Revision$";
97
98	/* mr_cryptlink - CRYPTLINK message handler
99	* parv[0] == CRYPTLINK
100	* parv[1] = command (SERV, AUTH)
101	* parv[2] = Parameters specific to each command (parv[1]):
102	* SERV - parc must be >= 5
103	* parv[0] == CRYPTLINK
104	* parv[1] == SERV
105	* parv[2] == server name
106	* parv[3] == keyphrase
107	* parv[4] == :server info (M-line)
108	* AUTH - parc must be >= 4
109	* parv[0] == CRYPTLINK
110	* parv[1] == AUTH
111	* parv[2] == cipher (eg. BF/168)
112	* parv[3] == keyphrase
113	*/
114	static void
115	mr_cryptlink(struct Client client_p, struct Client source_p,
116	int parc, char *parv[])
117	{
118	int i;
119
120	for (i = 0; cryptlink_cmd_table[i].handler; i++)
121	{
122	/* Traverse through the command table */
123	if (!irccmp(cryptlink_cmd_table[i].cmd, parv[1]))
124	{
125	/*
126	* Match found. Time to execute the function
127	*/
128	cryptlink_cmd_table[i].handler(client_p, source_p, parc, parv);
129	}
130	}
131	}
132
133	/*
134	* cryptlink_auth - CRYPTLINK AUTH message handler
135	* parv[1] = secret key
136	*/
137	static void
138	cryptlink_auth(struct Client client_p, struct Client source_p,
139	int parc, char *parv[])
140	{
141	struct EncCapability *ecap;
142	struct ConfItem *conf;
143	struct AccessItem *aconf;
144	int enc_len;
145	int len;
146	unsigned char *enc;
147	unsigned char *key;
148
149	if (parc < 4)
150	{
151	cryptlink_error(client_p, "AUTH", "Invalid params",
152	"CRYPTLINK AUTH - Invalid params");
153	return;
154	}
155
156	if (!IsWaitAuth(client_p))
157	return;
158
159	for (ecap = CipherTable; ecap->name; ecap++)
160	{
161	if ((!irccmp(ecap->name, parv[2])) &&
162	(IsCapableEnc(client_p, ecap->cap)))
163	{
164	client_p->localClient->in_cipher = ecap;
165	break;
166	}
167	}
168
169	if (client_p->localClient->in_cipher == NULL)
170	{
171	cryptlink_error(client_p, "AUTH", "Invalid cipher", "Invalid cipher");
172	return;
173	}
174
175	if (!(enc_len = unbase64_block(&enc, parv[3], strlen(parv[3]))))
176	{
177	cryptlink_error(client_p, "AUTH",
178	"Could not base64 decode response",
179	"Malformed CRYPTLINK AUTH reply");
180	return;
181	}
182
183	if (verify_private_key() == -1)
184	{
185	sendto_realops_flags(UMODE_ALL, L_ADMIN,
186	"verify_private_key() returned -1. Check log for information.");
187	}
188
189	key = MyMalloc(RSA_size(ServerInfo.rsa_private_key));
190	len = RSA_private_decrypt(enc_len, (unsigned char )enc,(unsigned char )key,
191	ServerInfo.rsa_private_key,
192	RSA_PKCS1_PADDING);
193
194	if (len < client_p->localClient->in_cipher->keylen)
195	{
196	report_crypto_errors();
197	if (len < 0)
198	{
199	cryptlink_error(client_p, "AUTH",
200	"Decryption failed",
201	"Malformed CRYPTLINK AUTH reply");
202	}
203	else
204	{
205	cryptlink_error(client_p, "AUTH",
206	"Not enough random data sent",
207	"Malformed CRYPTLINK AUTH reply");
208	}
209	MyFree(enc);
210	MyFree(key);
211	return;
212	}
213
214	if (memcmp(key, client_p->localClient->in_key,
215	client_p->localClient->in_cipher->keylen) != 0)
216	{
217	cryptlink_error(client_p, "AUTH",
218	"Unauthorized server connection attempt",
219	"Malformed CRYPTLINK AUTH reply");
220	return;
221	}
222
223	conf = find_conf_name(&client_p->localClient->confs,
224	client_p->name, SERVER_TYPE);
225
226	if (conf == NULL)
227	{
228	cryptlink_error(client_p, "AUTH",
229	"Lost C-line for server",
230	"Lost C-line");
231	return;
232	}
233
234	aconf = (struct AccessItem *)map_to_conf(conf);
235
236	if (!(client_p->localClient->out_cipher \|\|
237	(client_p->localClient->out_cipher = check_cipher(client_p, aconf))))
238	{
239	cryptlink_error(client_p, "AUTH",
240	"Couldn't find compatible cipher",
241	"Couldn't find compatible cipher");
242	return;
243	}
244
245	/* set hopcount */
246	client_p->hopcount = 1;
247
248	SetCryptIn(client_p);
249	ClearWaitAuth(client_p);
250	server_estab(client_p);
251	}
252
253	/*
254	* cryptlink_serv - CRYPTLINK SERV message handler
255	* parv[0] == CRYPTLINK
256	* parv[1] == SERV
257	* parv[2] == server name
258	* parv[3] == keyphrase
259	* parv[4] == :server info (M-line)
260	*/
261	static void
262	cryptlink_serv(struct Client client_p, struct Client source_p,
263	int parc, char *parv[])
264	{
265	char info[REALLEN + 1];
266	char *name;
267	struct Client *target_p;
268	char *key = client_p->localClient->out_key;
269	unsigned char *b64_key;
270	struct ConfItem *conf;
271	struct AccessItem *aconf;
272	char *encrypted;
273	const char *p;
274	int enc_len;
275
276	/*
277	if (client_p->name[0] != 0)
278	return;
279	*/
280
281	if ((parc < 5) \|\| (*parv[4] == '\0'))
282	{
283	cryptlink_error(client_p, "SERV", "Invalid params",
284	"CRYPTLINK SERV - Invalid params");
285	return;
286	}
287
288	if ((name = parse_cryptserv_args(client_p, parv, parc, info, key)) == NULL)
289	{
290	cryptlink_error(client_p, "SERV", "Invalid params",
291	"CRYPTLINK SERV - Invalid params");
292	return;
293	}
294
295	/* CRYPTLINK SERV support => TS support */
296	client_p->tsinfo = TS_DOESTS;
297
298	if (!valid_servname(name))
299	{
300	exit_client(client_p, client_p, "Bogus server name");
301	return;
302	}
303
304	/* Now we just have to call check_server and everything should be
305	* checked for us... -A1kmm. */
306	switch (check_server(name, client_p, CHECK_SERVER_CRYPTLINK))
307	{
308	case -1:
309	if (ConfigFileEntry.warn_no_nline)
310	{
311	cryptlink_error(client_p, "SERV",
312	"Unauthorized server connection attempt: No entry for server",
313	NULL);
314	}
315	exit_client(client_p, client_p, "Invalid server name");
316	return;
317	break;
318	case -2:
319	cryptlink_error(client_p, "SERV",
320	"Unauthorized server connection attempt: CRYPTLINK not "
321	"enabled on remote server",
322	"CRYPTLINK not enabled");
323	return;
324	break;
325	case -3:
326	cryptlink_error(client_p, "SERV",
327	"Unauthorized server connection attempt: Invalid host",
328	"Invalid host");
329	return;
330	break;
331	}
332
333	if ((target_p = find_server(name)))
334	{
335	/*
336	* This link is trying feed me a server that I already have
337	* access through another path -- multiple paths not accepted
338	* currently, kill this link immediately!!
339	*
340	* Rather than KILL the link which introduced it, KILL the
341	* youngest of the two links. -avalon
342	*
343	* Definitely don't do that here. This is from an unregistered
344	* connect - A1kmm.
345	*/
346	cryptlink_error(client_p, "SERV",
347	"Attempt to re-introduce existing server",
348	"Server Exists");
349	return;
350	}
351
352	conf = find_conf_name(&client_p->localClient->confs,
353	name, SERVER_TYPE);
354	if (conf == NULL)
355	{
356	cryptlink_error(client_p, "AUTH",
357	"Lost C-line for server",
358	"Lost C-line" );
359	return;
360	}
361
362	/*
363	* if we are connecting (Handshake), we already have the name from the
364	* connect {} block in client_p->name
365	*/
366	strlcpy(client_p->name, name, sizeof(client_p->name));
367
368	p = info;
369
370	if (!strncmp(info, "(H)", 3))
371	{
372	SetHidden(client_p);
373
374	if ((p = strchr(info, ' ')) != NULL)
375	{
376	p++;
377	if (*p == '\0')
378	p = "(Unknown Location)";
379	}
380	else
381	p = "(Unknown Location)";
382	}
383
384	strlcpy(client_p->info, p, sizeof(client_p->info));
385	client_p->hopcount = 0;
386
387	aconf = (struct AccessItem *)map_to_conf(conf);
388
389	if (!(client_p->localClient->out_cipher \|\|
390	(client_p->localClient->out_cipher = check_cipher(client_p, aconf))))
391	{
392	cryptlink_error(client_p, "AUTH",
393	"Couldn't find compatible cipher",
394	"Couldn't find compatible cipher");
395	return;
396	}
397
398	encrypted = MyMalloc(RSA_size(ServerInfo.rsa_private_key));
399	enc_len = RSA_public_encrypt(client_p->localClient->out_cipher->keylen,
400	(unsigned char *)key,
401	(unsigned char *)encrypted,
402	aconf->rsa_public_key,
403	RSA_PKCS1_PADDING);
404
405	if (enc_len <= 0)
406	{
407	report_crypto_errors();
408	MyFree(encrypted);
409	cryptlink_error(client_p, "AUTH",
410	"Couldn't encrypt data",
411	"Couldn't encrypt data");
412	return;
413	}
414
415	base64_block(&b64_key, encrypted, enc_len);
416
417	MyFree(encrypted);
418
419	if (!IsWaitAuth(client_p))
420	cryptlink_init(client_p, conf, NULL);
421
422	sendto_one(client_p, "CRYPTLINK AUTH %s %s",
423	client_p->localClient->out_cipher->name,
424	b64_key);
425
426	/* needed for old servers that can't shove data back into slink */
427	send_queued_write(client_p);
428
429	SetCryptOut(client_p);
430	MyFree(b64_key);
431	}
432
433	/* parse_cryptserv_args()
434	*
435	* inputs - parv parameters
436	* - parc count
437	* - info string (to be filled in by this routine)
438	* - key (to be filled in by this routine)
439	* output - NULL if invalid params, server name otherwise
440	* side effects - parv[2] is trimmed to HOSTLEN size if needed.
441	*/
442	static char *
443	parse_cryptserv_args(struct Client client_p, char parv[],
444	int parc, char info, char key)
445	{
446	char *name;
447	unsigned char tmp, out;
448	int len;
449	int decoded_len;
450
451	info[0] = '\0';
452
453	name = parv[2];
454
455	/* parv[2] contains encrypted auth data */
456	if (!(decoded_len = unbase64_block(&tmp, parv[3],
457	strlen(parv[3]))))
458	{
459	cryptlink_error(client_p, "SERV",
460	"Couldn't base64 decode data",
461	NULL);
462	return(NULL);
463	}
464
465	if (verify_private_key() == -1)
466	{
467	sendto_realops_flags(UMODE_ALL, L_ADMIN,
468	"verify_private_key() returned -1. Check log for information.");
469	}
470
471	if (ServerInfo.rsa_private_key == NULL)
472	{
473	cryptlink_error(client_p, "SERV", "No local private key found", NULL);
474	return(NULL);
475	}
476
477	out = MyMalloc(RSA_size(ServerInfo.rsa_private_key));
478	len = RSA_private_decrypt(decoded_len, tmp, out,
479	ServerInfo.rsa_private_key,
480	RSA_PKCS1_PADDING);
481
482	MyFree(tmp);
483
484	if (len < CIPHERKEYLEN)
485	{
486	report_crypto_errors();
487	if (len < 0)
488	{
489	cryptlink_error(client_p, "AUTH", "Decryption failed", NULL);
490	}
491	else
492	{
493	cryptlink_error(client_p, "AUTH", "Not enough random data sent", NULL);
494	}
495	MyFree(out);
496	return(NULL);
497	}
498
499	memcpy(key, out, CIPHERKEYLEN);
500	MyFree(out);
501
502	strlcpy(info, parv[4], REALLEN + 1);
503
504	if (strlen(name) > HOSTLEN)
505	name[HOSTLEN] = '\0';
506
507	return(name);
508	}
509	#endif