authd/providers/rdns.c

   1 /* authd/providers/rdns.c - rDNS lookup provider for authd
   2  * Copyright (c) 2016 Elizabeth Myers <elizabeth@interlinked.me>
   3  *
   4  * Permission to use, copy, modify, and/or distribute this software for any
   5  * purpose with or without fee is hereby granted, provided that the above
   6  * copyright notice and this permission notice is present in all copies.
   7  *
   8  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   9  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  10  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  11  * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
  12  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  13  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  14  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  15  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
  16  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  17  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  18  * POSSIBILITY OF SUCH DAMAGE.
  19  */
  20
  21 #include "stdinc.h"
  22 #include "rb_commio.h"
  23 #include "authd.h"
  24 #include "provider.h"
  25 #include "notice.h"
  26 #include "res.h"
  27 #include "dns.h"
  28
  29 struct user_query
  30 {
  31         struct dns_query *query;                /* Pending DNS query */
  32         time_t timeout;                         /* When the request times out */
  33 };
  34
  35 /* Goinked from old s_auth.c --Elizabeth */
  36 static const char *messages[] =
  37 {
  38         "*** Looking up your hostname...",
  39         "*** Found your hostname",
  40         "*** Couldn't look up your hostname",
  41         "*** Your hostname is too long, ignoring hostname",
  42 };
  43
  44 typedef enum
  45 {
  46         REPORT_LOOKUP,
  47         REPORT_FOUND,
  48         REPORT_FAIL,
  49         REPORT_TOOLONG,
  50 } dns_message;
  51
  52 static void client_fail(struct auth_client *auth, dns_message message);
  53 static void client_success(struct auth_client *auth);
  54 static void dns_answer_callback(const char *res, bool status, query_type type, void *data);
  55
  56 static struct ev_entry *timeout_ev;
  57 static EVH timeout_dns_queries_event;
  58 static int rdns_timeout = 15;
  59
  60 static void
  61 dns_answer_callback(const char *res, bool status, query_type type, void *data)
  62 {
  63         struct auth_client *auth = data;
  64         struct user_query *query = auth->data[PROVIDER_RDNS];
  65
  66         if(query == NULL || res == NULL || status == false)
  67                 client_fail(auth, REPORT_FAIL);
  68         else if(strlen(res) > HOSTLEN)
  69                 client_fail(auth, REPORT_TOOLONG);
  70         else
  71         {
  72                 rb_strlcpy(auth->hostname, res, HOSTLEN + 1);
  73                 client_success(auth);
  74         }
  75 }
  76
  77 /* Timeout outstanding queries */
  78 static void
  79 timeout_dns_queries_event(void *notused)
  80 {
  81         struct auth_client *auth;
  82         rb_dictionary_iter iter;
  83
  84         RB_DICTIONARY_FOREACH(auth, &iter, auth_clients)
  85         {
  86                 struct user_query *query = auth->data[PROVIDER_RDNS];
  87
  88                 if(query != NULL && query->timeout < rb_current_time())
  89                 {
  90                         client_fail(auth, REPORT_FAIL);
  91                         return;
  92                 }
  93         }
  94 }
  95
  96 static void
  97 client_fail(struct auth_client *auth, dns_message report)
  98 {
  99         struct user_query *query = auth->data[PROVIDER_RDNS];
 100
 101         if(query == NULL)
 102                 return;
 103
 104         rb_strlcpy(auth->hostname, "*", sizeof(auth->hostname));
 105
 106         notice_client(auth->cid, messages[report]);
 107         cancel_query(query->query);
 108
 109         rb_free(query);
 110         auth->data[PROVIDER_RDNS] = NULL;
 111
 112         provider_done(auth, PROVIDER_RDNS);
 113 }
 114
 115 static void
 116 client_success(struct auth_client *auth)
 117 {
 118         struct user_query *query = auth->data[PROVIDER_RDNS];
 119
 120         notice_client(auth->cid, messages[REPORT_FOUND]);
 121         cancel_query(query->query);
 122
 123         rb_free(query);
 124         auth->data[PROVIDER_RDNS] = NULL;
 125
 126         provider_done(auth, PROVIDER_RDNS);
 127 }
 128
 129 static bool
 130 rdns_init(void)
 131 {
 132         timeout_ev = rb_event_addish("timeout_dns_queries_event", timeout_dns_queries_event, NULL, 1);
 133         return (timeout_ev != NULL);
 134 }
 135
 136 static void
 137 rdns_destroy(void)
 138 {
 139         struct auth_client *auth;
 140         rb_dictionary_iter iter;
 141
 142         RB_DICTIONARY_FOREACH(auth, &iter, auth_clients)
 143         {
 144                 if(auth->data[PROVIDER_RDNS] != NULL)
 145                         client_fail(auth, REPORT_FAIL);
 146         }
 147
 148         rb_event_delete(timeout_ev);
 149 }
 150
 151 static bool
 152 rdns_start(struct auth_client *auth)
 153 {
 154         struct user_query *query = rb_malloc(sizeof(struct user_query));
 155
 156         query->timeout = rb_current_time() + rdns_timeout;
 157
 158         auth->data[PROVIDER_RDNS] = query;
 159
 160         query->query = lookup_hostname(auth->c_ip, dns_answer_callback, auth);
 161
 162         notice_client(auth->cid, messages[REPORT_LOOKUP]);
 163         set_provider_on(auth, PROVIDER_RDNS);
 164         return true;
 165 }
 166
 167 static void
 168 rdns_cancel(struct auth_client *auth)
 169 {
 170         struct user_query *query = auth->data[PROVIDER_RDNS];
 171
 172         if(query != NULL)
 173                 client_fail(auth, REPORT_FAIL);
 174 }
 175
 176 static void
 177 add_conf_dns_timeout(const char *key, int parc, const char **parv)
 178 {
 179         int timeout = atoi(parv[0]);
 180
 181         if(timeout < 0)
 182         {
 183                 warn_opers(L_CRIT, "BUG: DNS timeout < 0 (value: %d)", timeout);
 184                 return;
 185         }
 186
 187         rdns_timeout = timeout;
 188 }
 189
 190 struct auth_opts_handler rdns_options[] =
 191 {
 192         { "rdns_timeout", 1, add_conf_dns_timeout },
 193         { NULL, 0, NULL },
 194 };
 195
 196 struct auth_provider rdns_provider =
 197 {
 198         .id = PROVIDER_RDNS,
 199         .init = rdns_init,
 200         .destroy = rdns_destroy,
 201         .start = rdns_start,
 202         .cancel = rdns_cancel,
 203         .completed = NULL,
 204         .opt_handlers = rdns_options,
 205 };