trunk/src/auth.c

/*
 *  ircd-hybrid: an advanced, lightweight Internet Relay Chat Daemon (ircd)
 *
 *  Copyright (c) 1997-2018 ircd-hybrid development team
 *
 *  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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
 *  USA
 */

/*! \file auth.c
 * \brief Implementation of DNS and ident lookups.
 * \version $Id$
 */

/*
 * Changes:
 *   July 6, 1999 - Rewrote most of the code here. When a client connects
 *     to the server and passes initial socket validation checks, it
 *     is owned by this module (auth) which returns it to the rest of the
 *     server when dns and auth queries are finished. Until the client is
 *     released, the server does not know it exists and does not process
 *     any messages from it.
 *     --Bleep  Thomas Helvey <tomh@inxpress.net>
 */

#include "stdinc.h"
#include "list.h"
#include "ircd_defs.h"
#include "fdlist.h"
#include "auth.h"
#include "conf.h"
#include "client.h"
#include "event.h"
#include "irc_string.h"
#include "ircd.h"
#include "packet.h"
#include "res.h"
#include "s_bsd.h"
#include "log.h"
#include "send.h"
#include "memory.h"


enum
{
  REPORT_DO_DNS,
  REPORT_FIN_DNS,
  REPORT_FAIL_DNS,
  REPORT_DO_ID,
  REPORT_FIN_ID,
  REPORT_FAIL_ID,
  REPORT_IP_MISMATCH,
  REPORT_HOST_TOOLONG,
  REPORT_HOST_INVALID
};

static const char *const HeaderMessages[] =
{
  [REPORT_DO_DNS] = ":*** Looking up your hostname",
  [REPORT_FIN_DNS] = ":*** Found your hostname",
  [REPORT_FAIL_DNS] = ":*** Couldn't look up your hostname",
  [REPORT_DO_ID] = ":*** Checking Ident",
  [REPORT_FIN_ID] = ":*** Got Ident response",
  [REPORT_FAIL_ID] = ":*** No Ident response",
  [REPORT_IP_MISMATCH] = ":*** Your forward and reverse DNS do not match, ignoring hostname",
  [REPORT_HOST_TOOLONG] = ":*** Your hostname is too long, ignoring hostname",
  [REPORT_HOST_INVALID] = ":*** Your hostname contains illegal characters, ignoring hostname"
};

#define auth_sendheader(c, i) sendto_one_notice((c), &me, "%s", HeaderMessages[(i)])

static dlink_list auth_list;


/*! \brief Allocate a new auth request.
 * \param client The client being looked up.
 * \return The newly allocated auth request.
 */
static struct AuthRequest *
auth_make(struct Client *client)
{
  struct AuthRequest *auth = xcalloc(sizeof(*auth));

  auth->client = client;
  auth->client->connection->auth = auth;
  auth->timeout = CurrentTime + CONNECTTIMEOUT;

  return auth;
}

/*! \brief Unlink auth request from auth_list and free memory
 * \param auth The allocated auth request to cleanup.
 */
static void
auth_free(struct AuthRequest *auth)
{
  assert(dlinkFind(&auth_list, auth));
  dlinkDelete(&auth->node, &auth_list);
  assert(dlinkFind(&auth_list, auth) == NULL);

  xfree(auth);
}

/*! \brief Release auth client from auth system. This adds the client into the
 *         local client lists so it can be read by the main io processing loop.
 * \param auth Pointer to AuthRequest struct to release
 */
static void
auth_release_client(struct AuthRequest *auth)
{
  struct Client *client = auth->client;

  if (IsDoingAuth(auth) || IsDNSPending(auth))
    return;

  auth_free(auth);
  client->connection->auth = NULL;

  /*
   * When a client has auth'ed, we want to start reading what it sends
   * us. This is what read_packet() does.
   *     -- adrian
   */
  client->connection->allow_read = MAX_FLOOD;
  comm_setflush(client->connection->fd, 1000, flood_recalc, client);

  client->connection->since     = CurrentTime;
  client->connection->lasttime  = CurrentTime;
  client->connection->firsttime = CurrentTime;
  AddFlag(client, FLAGS_FINISHED_AUTH);

  strlcpy(client->realhost, client->host, sizeof(client->realhost));

  read_packet(client->connection->fd, client);
}

/*! Checks if a hostname is valid and doesn't contain illegal characters
 * \param hostname The string to verify
 * \return 1 if it is valid, 0 if it isn't
 */
static int
auth_verify_hostname(const char *hostname)
{
  const char *p = hostname;

  assert(p);

  if (EmptyString(p) || *p == '.' || *p == ':')
    return 0;

  for (; *p; ++p)
    if (!IsHostChar(*p))
      return 0;

  return 1;
}

/*! \brief Handle a complete DNS lookup. Send the client on its way to a connection
 *         completion, regardless of success or failure.
 * \param vptr The pending struct AuthRequest.
 * \param addr IP address being resolved.
 * \param name Resolved name, or NULL if lookup failed.
 * \param namelength String length of the resolved hostname pointed by 'name'
 */
static void
auth_dns_callback(void *vptr, const struct irc_ssaddr *addr, const char *name, size_t namelength)
{
  struct AuthRequest *const auth = vptr;

  ClearDNSPending(auth);

  if (EmptyString(name))
    auth_sendheader(auth->client, REPORT_FAIL_DNS);
  else
  {
    if (auth->client->ip.ss.ss_family == AF_INET6)
    {
      const struct sockaddr_in6 *const v6 = (const struct sockaddr_in6 *)&auth->client->ip;
      const struct sockaddr_in6 *const v6dns = (const struct sockaddr_in6 *)addr;

      if (memcmp(&v6->sin6_addr, &v6dns->sin6_addr, sizeof(struct in6_addr)))
      {
        auth_sendheader(auth->client, REPORT_IP_MISMATCH);
        auth_release_client(auth);
        return;
      }
    }
    else
    {
      const struct sockaddr_in *const v4 = (const struct sockaddr_in *)&auth->client->ip;
      const struct sockaddr_in *const v4dns = (const struct sockaddr_in *)addr;

      if (v4->sin_addr.s_addr != v4dns->sin_addr.s_addr)
      {
        auth_sendheader(auth->client, REPORT_IP_MISMATCH);
        auth_release_client(auth);
        return;
      }
    }

    if (namelength > HOSTLEN)
      auth_sendheader(auth->client, REPORT_HOST_TOOLONG);
    else if (auth_verify_hostname(name) == 0)
      auth_sendheader(auth->client, REPORT_HOST_INVALID);
    else
    {
      strlcpy(auth->client->host, name, sizeof(auth->client->host));
      auth_sendheader(auth->client, REPORT_FIN_DNS);
    }
  }

  auth_release_client(auth);
}

/*
 * auth_error - handle auth send errors
 */
static void
auth_error(struct AuthRequest *auth)
{
  assert(auth);
  assert(auth->fd);

  ++ServerStats.is_abad;

  fd_close(auth->fd);
  auth->fd = NULL;

  ClearAuth(auth);

  auth_sendheader(auth->client, REPORT_FAIL_ID);

  auth_release_client(auth);
}

/** Enum used to index ident reply fields in a human-readable way. */
enum IdentReplyFields
{
  IDENT_PORT_NUMBERS,
  IDENT_REPLY_TYPE,
  IDENT_OS_TYPE,
  IDENT_INFO,
  USERID_TOKEN_COUNT
};

/** Parse an ident reply line and extract the userid from it.
 * \param reply The ident reply line.
 * \return The userid, or NULL on parse failure.
 */
static const char *
auth_check_ident_reply(char *const reply)
{
  char *token = NULL, *end = NULL;
  char *vector[USERID_TOKEN_COUNT];
  const unsigned int count = token_vector(reply, ':', vector, USERID_TOKEN_COUNT);

  if (USERID_TOKEN_COUNT != count)
    return NULL;

  /*
   * Second token is the reply type
   */
  token = vector[IDENT_REPLY_TYPE];

  if (EmptyString(token))
    return NULL;

  while (IsSpace(*token))
    ++token;

  if (strncmp(token, "USERID", 6))
    return NULL;

  /*
   * Third token is the os type
   */
  token = vector[IDENT_OS_TYPE];

  if (EmptyString(token))
    return NULL;

  while (IsSpace(*token))
   ++token;

  /*
   * Unless "OTHER" is specified as the operating system type, the server
   * is expected to return the "normal" user identification of the owner
   * of this connection. "Normal" in this context may be taken to mean a
   * string of characters which uniquely identifies the connection owner
   * such as a user identifier assigned by the system administrator and
   * used by such user as a mail identifier, or as the "user" part of a
   * user/password pair used to gain access to system resources. When an
   * operating system is specified (e.g., anything but "OTHER"), the user
   * identifier is expected to be in a more or less immediately useful
   * form - e.g., something that could be used as an argument to "finger"
   * or as a mail address.
   */
  if (strncmp(token, "OTHER", 5) == 0)
    return NULL;

  /*
   * Fourth token is the username
   */
  token = vector[IDENT_INFO];

  if (EmptyString(token))
    return NULL;

  while (IsSpace(*token))
    ++token;

  while (*token == '~' || *token == '^')
    ++token;

  /*
   * Look for the end of the username, terminators are '\0, @, <SPACE>, :'
   */
  for (end = token; *end; ++end)
    if (IsSpace(*end) || '@' == *end || ':' == *end)
      break;
  *end = '\0';

  return token;
}

/*! \brief Read the reply (if any) from the ident server we connected to. We
 *         only give it one shot, if the reply isn't good the first time fail
 *         the authentication entirely. --Bleep
 * \param F The socket/fd to read from.
 * \param data The request to read.
 */
static void
auth_read_reply(fde_t *F, void *data)
{
  struct AuthRequest *const auth = data;
  const char *username = NULL;
  ssize_t len = 0;
  char buf[RFC1413_BUFSIZ + 1];

  assert(auth->fd == F);

  if ((len = recv(auth->fd->fd, buf, RFC1413_BUFSIZ, 0)) > 0)
  {
    buf[len] = '\0';
    username = auth_check_ident_reply(buf);
  }

  fd_close(auth->fd);
  auth->fd = NULL;

  ClearAuth(auth);

  if (EmptyString(username))
  {
    auth_sendheader(auth->client, REPORT_FAIL_ID);
    ++ServerStats.is_abad;
  }
  else
  {
    strlcpy(auth->client->username, username, sizeof(auth->client->username));
    auth_sendheader(auth->client, REPORT_FIN_ID);
    ++ServerStats.is_asuc;
    AddFlag(auth->client, FLAGS_GOTID);
  }

  auth_release_client(auth);
}

/*
 * auth_connect_callback() - deal with the result of comm_connect_tcp()
 *
 * If the connection failed, we simply close the auth fd and report
 * a failure. If the connection suceeded send the ident server a query
 * giving "theirport , ourport". The write is only attempted *once* so
 * it is deemed to be a fail if the entire write doesn't write all the
 * data given.  This shouldnt be a problem since the socket should have
 * a write buffer far greater than this message to store it in should
 * problems arise. -avalon
 */
static void
auth_connect_callback(fde_t *F, int error, void *data)
{
  struct AuthRequest *const auth = data;
  struct irc_ssaddr us;
  struct irc_ssaddr them;
  char authbuf[16];
  ssize_t len = 0;
  socklen_t ulen = sizeof(struct irc_ssaddr);
  socklen_t tlen = sizeof(struct irc_ssaddr);
  uint16_t uport, tport;
  struct sockaddr_in6 *v6;

  if (error != COMM_OK)
  {
    auth_error(auth);
    return;
  }

  assert(auth->fd == F);

  if (getsockname(auth->client->connection->fd->fd, (struct sockaddr *)&us, &ulen) ||
      getpeername(auth->client->connection->fd->fd, (struct sockaddr *)&them, &tlen))
  {
    report_error(L_ALL, "auth get{sock,peer}name error %s:%s",
                 client_get_name(auth->client, SHOW_IP), errno);
    auth_error(auth);
    return;
  }

  v6 = (struct sockaddr_in6 *)&us;
  uport = ntohs(v6->sin6_port);
  v6 = (struct sockaddr_in6 *)&them;
  tport = ntohs(v6->sin6_port);

  len = snprintf(authbuf, sizeof(authbuf), "%u, %u\r\n", tport, uport);

  if (send(F->fd, authbuf, len, 0) != len)
  {
    auth_error(auth);
    return;
  }

  comm_setselect(F, COMM_SELECT_READ, auth_read_reply, auth, 0);
}

/*! \brief Flag the client to show an attempt to contact the ident server on
 *         the client's host. Should the connect or any later phase of the
 *         identifying process fail, it is aborted and the user is given a
 *         username of "unknown".
 * \param auth The request for which to start the ident lookup.
 */
static void
auth_start_query(struct AuthRequest *auth)
{
  struct irc_ssaddr localaddr;
  socklen_t locallen = sizeof(struct irc_ssaddr);
  struct sockaddr_in6 *v6;

  /* Open a socket of the same type as the client socket */
  int fd = comm_socket(auth->client->ip.ss.ss_family, SOCK_STREAM, 0);
  if (fd == -1)
  {
    report_error(L_ALL, "creating auth stream socket %s:%s",
                 client_get_name(auth->client, SHOW_IP), errno);
    ++ServerStats.is_abad;
    return;
  }

  auth->fd = fd_open(fd, 1, "ident");

  SetDoingAuth(auth);
  auth_sendheader(auth->client, REPORT_DO_ID);

  /*
   * Get the local address of the client and bind to that to
   * make the auth request.
   */
  memset(&localaddr, 0, locallen);
  getsockname(auth->client->connection->fd->fd, (struct sockaddr *)&localaddr, &locallen);

  remove_ipv6_mapping(&localaddr);
  v6 = (struct sockaddr_in6 *)&localaddr;
  v6->sin6_port = htons(0);
  localaddr.ss_port = htons(0);

  comm_connect_tcp(auth->fd, auth->client->sockhost, RFC1413_PORT,
      (struct sockaddr *)&localaddr, localaddr.ss_len, auth_connect_callback,
      auth, auth->client->ip.ss.ss_family,
      GlobalSetOptions.ident_timeout);
}

/*
 * auth_start
 *
 * inputs       - pointer to client to auth
 * output       - NONE
 * side effects - starts auth (identd) and dns queries for a client
 */
void
auth_start(struct Client *client_p)
{
  struct AuthRequest *auth = auth_make(client_p);

  dlinkAddTail(auth, &auth->node, &auth_list);

  auth_sendheader(client_p, REPORT_DO_DNS);

  SetDNSPending(auth);

  if (ConfigGeneral.disable_auth == 0)
    auth_start_query(auth);

  gethost_byaddr(auth_dns_callback, auth, &client_p->ip);
}

/*
 * auth_delete()
 */
void
auth_delete(struct AuthRequest *auth)
{
  if (IsDoingAuth(auth))
  {
    fd_close(auth->fd);
    auth->fd = NULL;

    ClearAuth(auth);
  }

  if (IsDNSPending(auth))
  {
    delete_resolver_queries(auth);
    ClearDNSPending(auth);
  }

  auth_free(auth);
}

/*
 * auth_timeout_queries - timeout resolver and identd requests
 * allow clients through if requests failed
 */
static void
auth_timeout_queries(void *notused)
{
  dlink_node *node, *node_next;

  DLINK_FOREACH_SAFE(node, node_next, auth_list.head)
  {
    struct AuthRequest *auth = node->data;

    if (auth->timeout > CurrentTime)
      break;

    if (IsDoingAuth(auth))
    {
      ++ServerStats.is_abad;

      fd_close(auth->fd);
      auth->fd = NULL;

      ClearAuth(auth);

      auth_sendheader(auth->client, REPORT_FAIL_ID);
    }

    if (IsDNSPending(auth))
    {
      delete_resolver_queries(auth);
      ClearDNSPending(auth);

      auth_sendheader(auth->client, REPORT_FAIL_DNS);
    }

    auth_release_client(auth);
  }
}

/* auth_init
 *
 * Initialise the auth code
 */
void
auth_init(void)
{
  static struct event timeout_auth_queries =
  {
    .name = "auth_timeout_queries",
    .handler = auth_timeout_queries,
    .when = 1
  };

  event_add(&timeout_auth_queries, NULL);
}
Revision:	8620
Committed:	Sat Nov 3 17:46:37 2018 UTC (6 years, 9 months ago) by michael
Content type:	text/x-csrc
File size:	15168 byte(s)
Log Message:	- Stylistic changes
#	Content
1	/*
2	* ircd-hybrid: an advanced, lightweight Internet Relay Chat Daemon (ircd)
3	*
4	* Copyright (c) 1997-2018 ircd-hybrid development team
5	*
6	* This program is free software; you can redistribute it and/or modify
7	* it under the terms of the GNU General Public License as published by
8	* the Free Software Foundation; either version 2 of the License, or
9	* (at your option) any later version.
10	*
11	* This program is distributed in the hope that it will be useful,
12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14	* GNU General Public License for more details.
15	*
16	* You should have received a copy of the GNU General Public License
17	* along with this program; if not, write to the Free Software
18	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
19	* USA
20	*/
21
22	/*! \file auth.c
23	* \brief Implementation of DNS and ident lookups.
24	* \version $Id$
25	*/
26
27	/*
28	* Changes:
29	* July 6, 1999 - Rewrote most of the code here. When a client connects
30	* to the server and passes initial socket validation checks, it
31	* is owned by this module (auth) which returns it to the rest of the
32	* server when dns and auth queries are finished. Until the client is
33	* released, the server does not know it exists and does not process
34	* any messages from it.
35	* --Bleep Thomas Helvey <tomh@inxpress.net>
36	*/
37
38	#include "stdinc.h"
39	#include "list.h"
40	#include "ircd_defs.h"
41	#include "fdlist.h"
42	#include "auth.h"
43	#include "conf.h"
44	#include "client.h"
45	#include "event.h"
46	#include "irc_string.h"
47	#include "ircd.h"
48	#include "packet.h"
49	#include "res.h"
50	#include "s_bsd.h"
51	#include "log.h"
52	#include "send.h"
53	#include "memory.h"
54
55
56	enum
57	{
58	REPORT_DO_DNS,
59	REPORT_FIN_DNS,
60	REPORT_FAIL_DNS,
61	REPORT_DO_ID,
62	REPORT_FIN_ID,
63	REPORT_FAIL_ID,
64	REPORT_IP_MISMATCH,
65	REPORT_HOST_TOOLONG,
66	REPORT_HOST_INVALID
67	};
68
69	static const char *const HeaderMessages[] =
70	{
71	[REPORT_DO_DNS] = ":*** Looking up your hostname",
72	[REPORT_FIN_DNS] = ":*** Found your hostname",
73	[REPORT_FAIL_DNS] = ":*** Couldn't look up your hostname",
74	[REPORT_DO_ID] = ":*** Checking Ident",
75	[REPORT_FIN_ID] = ":*** Got Ident response",
76	[REPORT_FAIL_ID] = ":*** No Ident response",
77	[REPORT_IP_MISMATCH] = ":*** Your forward and reverse DNS do not match, ignoring hostname",
78	[REPORT_HOST_TOOLONG] = ":*** Your hostname is too long, ignoring hostname",
79	[REPORT_HOST_INVALID] = ":*** Your hostname contains illegal characters, ignoring hostname"
80	};
81
82	#define auth_sendheader(c, i) sendto_one_notice((c), &me, "%s", HeaderMessages[(i)])
83
84	static dlink_list auth_list;
85
86
87	/*! \brief Allocate a new auth request.
88	* \param client The client being looked up.
89	* \return The newly allocated auth request.
90	*/
91	static struct AuthRequest *
92	auth_make(struct Client *client)
93	{
94	struct AuthRequest auth = xcalloc(sizeof(auth));
95
96	auth->client = client;
97	auth->client->connection->auth = auth;
98	auth->timeout = CurrentTime + CONNECTTIMEOUT;
99
100	return auth;
101	}
102
103	/*! \brief Unlink auth request from auth_list and free memory
104	* \param auth The allocated auth request to cleanup.
105	*/
106	static void
107	auth_free(struct AuthRequest *auth)
108	{
109	assert(dlinkFind(&auth_list, auth));
110	dlinkDelete(&auth->node, &auth_list);
111	assert(dlinkFind(&auth_list, auth) == NULL);
112
113	xfree(auth);
114	}
115
116	/*! \brief Release auth client from auth system. This adds the client into the
117	* local client lists so it can be read by the main io processing loop.
118	* \param auth Pointer to AuthRequest struct to release
119	*/
120	static void
121	auth_release_client(struct AuthRequest *auth)
122	{
123	struct Client *client = auth->client;
124
125	if (IsDoingAuth(auth) \|\| IsDNSPending(auth))
126	return;
127
128	auth_free(auth);
129	client->connection->auth = NULL;
130
131	/*
132	* When a client has auth'ed, we want to start reading what it sends
133	* us. This is what read_packet() does.
134	* -- adrian
135	*/
136	client->connection->allow_read = MAX_FLOOD;
137	comm_setflush(client->connection->fd, 1000, flood_recalc, client);
138
139	client->connection->since = CurrentTime;
140	client->connection->lasttime = CurrentTime;
141	client->connection->firsttime = CurrentTime;
142	AddFlag(client, FLAGS_FINISHED_AUTH);
143
144	strlcpy(client->realhost, client->host, sizeof(client->realhost));
145
146	read_packet(client->connection->fd, client);
147	}
148
149	/*! Checks if a hostname is valid and doesn't contain illegal characters
150	* \param hostname The string to verify
151	* \return 1 if it is valid, 0 if it isn't
152	*/
153	static int
154	auth_verify_hostname(const char *hostname)
155	{
156	const char *p = hostname;
157
158	assert(p);
159
160	if (EmptyString(p) \|\| p == '.' \|\| p == ':')
161	return 0;
162
163	for (; *p; ++p)
164	if (!IsHostChar(*p))
165	return 0;
166
167	return 1;
168	}
169
170	/*! \brief Handle a complete DNS lookup. Send the client on its way to a connection
171	* completion, regardless of success or failure.
172	* \param vptr The pending struct AuthRequest.
173	* \param addr IP address being resolved.
174	* \param name Resolved name, or NULL if lookup failed.
175	* \param namelength String length of the resolved hostname pointed by 'name'
176	*/
177	static void
178	auth_dns_callback(void vptr, const struct irc_ssaddr addr, const char *name, size_t namelength)
179	{
180	struct AuthRequest *const auth = vptr;
181
182	ClearDNSPending(auth);
183
184	if (EmptyString(name))
185	auth_sendheader(auth->client, REPORT_FAIL_DNS);
186	else
187	{
188	if (auth->client->ip.ss.ss_family == AF_INET6)
189	{
190	const struct sockaddr_in6 const v6 = (const struct sockaddr_in6 )&auth->client->ip;
191	const struct sockaddr_in6 const v6dns = (const struct sockaddr_in6 )addr;
192
193	if (memcmp(&v6->sin6_addr, &v6dns->sin6_addr, sizeof(struct in6_addr)))
194	{
195	auth_sendheader(auth->client, REPORT_IP_MISMATCH);
196	auth_release_client(auth);
197	return;
198	}
199	}
200	else
201	{
202	const struct sockaddr_in const v4 = (const struct sockaddr_in )&auth->client->ip;
203	const struct sockaddr_in const v4dns = (const struct sockaddr_in )addr;
204
205	if (v4->sin_addr.s_addr != v4dns->sin_addr.s_addr)
206	{
207	auth_sendheader(auth->client, REPORT_IP_MISMATCH);
208	auth_release_client(auth);
209	return;
210	}
211	}
212
213	if (namelength > HOSTLEN)
214	auth_sendheader(auth->client, REPORT_HOST_TOOLONG);
215	else if (auth_verify_hostname(name) == 0)
216	auth_sendheader(auth->client, REPORT_HOST_INVALID);
217	else
218	{
219	strlcpy(auth->client->host, name, sizeof(auth->client->host));
220	auth_sendheader(auth->client, REPORT_FIN_DNS);
221	}
222	}
223
224	auth_release_client(auth);
225	}
226
227	/*
228	* auth_error - handle auth send errors
229	*/
230	static void
231	auth_error(struct AuthRequest *auth)
232	{
233	assert(auth);
234	assert(auth->fd);
235
236	++ServerStats.is_abad;
237
238	fd_close(auth->fd);
239	auth->fd = NULL;
240
241	ClearAuth(auth);
242
243	auth_sendheader(auth->client, REPORT_FAIL_ID);
244
245	auth_release_client(auth);
246	}
247
248	/** Enum used to index ident reply fields in a human-readable way. */
249	enum IdentReplyFields
250	{
251	IDENT_PORT_NUMBERS,
252	IDENT_REPLY_TYPE,
253	IDENT_OS_TYPE,
254	IDENT_INFO,
255	USERID_TOKEN_COUNT
256	};
257
258	/** Parse an ident reply line and extract the userid from it.
259	* \param reply The ident reply line.
260	* \return The userid, or NULL on parse failure.
261	*/
262	static const char *
263	auth_check_ident_reply(char *const reply)
264	{
265	char token = NULL, end = NULL;
266	char *vector[USERID_TOKEN_COUNT];
267	const unsigned int count = token_vector(reply, ':', vector, USERID_TOKEN_COUNT);
268
269	if (USERID_TOKEN_COUNT != count)
270	return NULL;
271
272	/*
273	* Second token is the reply type
274	*/
275	token = vector[IDENT_REPLY_TYPE];
276
277	if (EmptyString(token))
278	return NULL;
279
280	while (IsSpace(*token))
281	++token;
282
283	if (strncmp(token, "USERID", 6))
284	return NULL;
285
286	/*
287	* Third token is the os type
288	*/
289	token = vector[IDENT_OS_TYPE];
290
291	if (EmptyString(token))
292	return NULL;
293
294	while (IsSpace(*token))
295	++token;
296
297	/*
298	* Unless "OTHER" is specified as the operating system type, the server
299	* is expected to return the "normal" user identification of the owner
300	* of this connection. "Normal" in this context may be taken to mean a
301	* string of characters which uniquely identifies the connection owner
302	* such as a user identifier assigned by the system administrator and
303	* used by such user as a mail identifier, or as the "user" part of a
304	* user/password pair used to gain access to system resources. When an
305	* operating system is specified (e.g., anything but "OTHER"), the user
306	* identifier is expected to be in a more or less immediately useful
307	* form - e.g., something that could be used as an argument to "finger"
308	* or as a mail address.
309	*/
310	if (strncmp(token, "OTHER", 5) == 0)
311	return NULL;
312
313	/*
314	* Fourth token is the username
315	*/
316	token = vector[IDENT_INFO];
317
318	if (EmptyString(token))
319	return NULL;
320
321	while (IsSpace(*token))
322	++token;
323
324	while (token == '~' \|\| token == '^')
325	++token;
326
327	/*
328	* Look for the end of the username, terminators are '\0, @, <SPACE>, :'
329	*/
330	for (end = token; *end; ++end)
331	if (IsSpace(end) \|\| '@' == end \|\| ':' == *end)
332	break;
333	*end = '\0';
334
335	return token;
336	}
337
338	/*! \brief Read the reply (if any) from the ident server we connected to. We
339	* only give it one shot, if the reply isn't good the first time fail
340	* the authentication entirely. --Bleep
341	* \param F The socket/fd to read from.
342	* \param data The request to read.
343	*/
344	static void
345	auth_read_reply(fde_t F, void data)
346	{
347	struct AuthRequest *const auth = data;
348	const char *username = NULL;
349	ssize_t len = 0;
350	char buf[RFC1413_BUFSIZ + 1];
351
352	assert(auth->fd == F);
353
354	if ((len = recv(auth->fd->fd, buf, RFC1413_BUFSIZ, 0)) > 0)
355	{
356	buf[len] = '\0';
357	username = auth_check_ident_reply(buf);
358	}
359
360	fd_close(auth->fd);
361	auth->fd = NULL;
362
363	ClearAuth(auth);
364
365	if (EmptyString(username))
366	{
367	auth_sendheader(auth->client, REPORT_FAIL_ID);
368	++ServerStats.is_abad;
369	}
370	else
371	{
372	strlcpy(auth->client->username, username, sizeof(auth->client->username));
373	auth_sendheader(auth->client, REPORT_FIN_ID);
374	++ServerStats.is_asuc;
375	AddFlag(auth->client, FLAGS_GOTID);
376	}
377
378	auth_release_client(auth);
379	}
380
381	/*
382	* auth_connect_callback() - deal with the result of comm_connect_tcp()
383	*
384	* If the connection failed, we simply close the auth fd and report
385	* a failure. If the connection suceeded send the ident server a query
386	* giving "theirport , ourport". The write is only attempted once so
387	* it is deemed to be a fail if the entire write doesn't write all the
388	* data given. This shouldnt be a problem since the socket should have
389	* a write buffer far greater than this message to store it in should
390	* problems arise. -avalon
391	*/
392	static void
393	auth_connect_callback(fde_t F, int error, void data)
394	{
395	struct AuthRequest *const auth = data;
396	struct irc_ssaddr us;
397	struct irc_ssaddr them;
398	char authbuf[16];
399	ssize_t len = 0;
400	socklen_t ulen = sizeof(struct irc_ssaddr);
401	socklen_t tlen = sizeof(struct irc_ssaddr);
402	uint16_t uport, tport;
403	struct sockaddr_in6 *v6;
404
405	if (error != COMM_OK)
406	{
407	auth_error(auth);
408	return;
409	}
410
411	assert(auth->fd == F);
412
413	if (getsockname(auth->client->connection->fd->fd, (struct sockaddr *)&us, &ulen) \|\|
414	getpeername(auth->client->connection->fd->fd, (struct sockaddr *)&them, &tlen))
415	{
416	report_error(L_ALL, "auth get{sock,peer}name error %s:%s",
417	client_get_name(auth->client, SHOW_IP), errno);
418	auth_error(auth);
419	return;
420	}
421
422	v6 = (struct sockaddr_in6 *)&us;
423	uport = ntohs(v6->sin6_port);
424	v6 = (struct sockaddr_in6 *)&them;
425	tport = ntohs(v6->sin6_port);
426
427	len = snprintf(authbuf, sizeof(authbuf), "%u, %u\r\n", tport, uport);
428
429	if (send(F->fd, authbuf, len, 0) != len)
430	{
431	auth_error(auth);
432	return;
433	}
434
435	comm_setselect(F, COMM_SELECT_READ, auth_read_reply, auth, 0);
436	}
437
438	/*! \brief Flag the client to show an attempt to contact the ident server on
439	* the client's host. Should the connect or any later phase of the
440	* identifying process fail, it is aborted and the user is given a
441	* username of "unknown".
442	* \param auth The request for which to start the ident lookup.
443	*/
444	static void
445	auth_start_query(struct AuthRequest *auth)
446	{
447	struct irc_ssaddr localaddr;
448	socklen_t locallen = sizeof(struct irc_ssaddr);
449	struct sockaddr_in6 *v6;
450
451	/* Open a socket of the same type as the client socket */
452	int fd = comm_socket(auth->client->ip.ss.ss_family, SOCK_STREAM, 0);
453	if (fd == -1)
454	{
455	report_error(L_ALL, "creating auth stream socket %s:%s",
456	client_get_name(auth->client, SHOW_IP), errno);
457	++ServerStats.is_abad;
458	return;
459	}
460
461	auth->fd = fd_open(fd, 1, "ident");
462
463	SetDoingAuth(auth);
464	auth_sendheader(auth->client, REPORT_DO_ID);
465
466	/*
467	* Get the local address of the client and bind to that to
468	* make the auth request.
469	*/
470	memset(&localaddr, 0, locallen);
471	getsockname(auth->client->connection->fd->fd, (struct sockaddr *)&localaddr, &locallen);
472
473	remove_ipv6_mapping(&localaddr);
474	v6 = (struct sockaddr_in6 *)&localaddr;
475	v6->sin6_port = htons(0);
476	localaddr.ss_port = htons(0);
477
478	comm_connect_tcp(auth->fd, auth->client->sockhost, RFC1413_PORT,
479	(struct sockaddr *)&localaddr, localaddr.ss_len, auth_connect_callback,
480	auth, auth->client->ip.ss.ss_family,
481	GlobalSetOptions.ident_timeout);
482	}
483
484	/*
485	* auth_start
486	*
487	* inputs - pointer to client to auth
488	* output - NONE
489	* side effects - starts auth (identd) and dns queries for a client
490	*/
491	void
492	auth_start(struct Client *client_p)
493	{
494	struct AuthRequest *auth = auth_make(client_p);
495
496	dlinkAddTail(auth, &auth->node, &auth_list);
497
498	auth_sendheader(client_p, REPORT_DO_DNS);
499
500	SetDNSPending(auth);
501
502	if (ConfigGeneral.disable_auth == 0)
503	auth_start_query(auth);
504
505	gethost_byaddr(auth_dns_callback, auth, &client_p->ip);
506	}
507
508	/*
509	* auth_delete()
510	*/
511	void
512	auth_delete(struct AuthRequest *auth)
513	{
514	if (IsDoingAuth(auth))
515	{
516	fd_close(auth->fd);
517	auth->fd = NULL;
518
519	ClearAuth(auth);
520	}
521
522	if (IsDNSPending(auth))
523	{
524	delete_resolver_queries(auth);
525	ClearDNSPending(auth);
526	}
527
528	auth_free(auth);
529	}
530
531	/*
532	* auth_timeout_queries - timeout resolver and identd requests
533	* allow clients through if requests failed
534	*/
535	static void
536	auth_timeout_queries(void *notused)
537	{
538	dlink_node node, node_next;
539
540	DLINK_FOREACH_SAFE(node, node_next, auth_list.head)
541	{
542	struct AuthRequest *auth = node->data;
543
544	if (auth->timeout > CurrentTime)
545	break;
546
547	if (IsDoingAuth(auth))
548	{
549	++ServerStats.is_abad;
550
551	fd_close(auth->fd);
552	auth->fd = NULL;
553
554	ClearAuth(auth);
555
556	auth_sendheader(auth->client, REPORT_FAIL_ID);
557	}
558
559	if (IsDNSPending(auth))
560	{
561	delete_resolver_queries(auth);
562	ClearDNSPending(auth);
563
564	auth_sendheader(auth->client, REPORT_FAIL_DNS);
565	}
566
567	auth_release_client(auth);
568	}
569	}
570
571	/* auth_init
572	*
573	* Initialise the auth code
574	*/
575	void
576	auth_init(void)
577	{
578	static struct event timeout_auth_queries =
579	{
580	.name = "auth_timeout_queries",
581	.handler = auth_timeout_queries,
582	.when = 1
583	};
584
585	event_add(&timeout_auth_queries, NULL);
586	}