authd/providers/ident.c

   1 /* authd/providers/ident.c - ident 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 /* Largely adapted from old s_auth.c, but reworked for authd. rDNS code
  22  * moved to its own provider.
  23  *
  24  * --Elizafox 13 March 2016
  25  */
  26
  27 #include "stdinc.h"
  28 #include "match.h"
  29 #include "authd.h"
  30 #include "notice.h"
  31 #include "provider.h"
  32 #include "res.h"
  33
  34 #define IDENT_BUFSIZE 128
  35
  36 struct ident_query
  37 {
  38         rb_fde_t *F;                            /* Our FD */
  39 };
  40
  41 /* Goinked from old s_auth.c --Elizafox */
  42 static const char *messages[] =
  43 {
  44         "*** Checking Ident",
  45         "*** Got Ident response",
  46         "*** No Ident response",
  47         "*** Cannot verify ident validity, ignoring ident",
  48         "*** Ident disabled, not checking ident",
  49 };
  50
  51 typedef enum
  52 {
  53         REPORT_LOOKUP,
  54         REPORT_FOUND,
  55         REPORT_FAIL,
  56         REPORT_INVALID,
  57         REPORT_DISABLED,
  58 } ident_message;
  59
  60 static CNCB ident_connected;
  61 static PF read_ident_reply;
  62
  63 static void client_fail(struct auth_client *auth, ident_message message);
  64 static void client_success(struct auth_client *auth);
  65 static char * get_valid_ident(char *buf);
  66
  67 static int ident_timeout = 5;
  68 static bool ident_enable = true;
  69
  70
  71 /*
  72  * ident_connected() - deal with the result of rb_connect_tcp()
  73  *
  74  * If the connection failed, we simply close the auth fd and report
  75  * a failure. If the connection suceeded send the ident server a query
  76  * giving "theirport , ourport". The write is only attempted *once* so
  77  * it is deemed to be a fail if the entire write doesn't write all the
  78  * data given.  This shouldnt be a problem since the socket should have
  79  * a write buffer far greater than this message to store it in should
  80  * problems arise. -avalon
  81  */
  82 static void
  83 ident_connected(rb_fde_t *F __unused, int error, void *data)
  84 {
  85         struct auth_client *auth = data;
  86         struct ident_query *query;
  87         char authbuf[32];
  88         int authlen;
  89
  90         lrb_assert(auth != NULL);
  91         query = get_provider_data(auth, PROVIDER_IDENT);
  92         lrb_assert(query != NULL);
  93
  94         /* Check the error */
  95         if(error != RB_OK)
  96         {
  97                 /* We had an error during connection :( */
  98                 client_fail(auth, REPORT_FAIL);
  99                 return;
 100         }
 101
 102         snprintf(authbuf, sizeof(authbuf), "%u , %u\r\n",
 103                         auth->c_port, auth->l_port);
 104         authlen = strlen(authbuf);
 105
 106         if(rb_write(query->F, authbuf, authlen) != authlen)
 107         {
 108                 client_fail(auth, REPORT_FAIL);
 109                 return;
 110         }
 111
 112         read_ident_reply(query->F, auth);
 113 }
 114
 115 static void
 116 read_ident_reply(rb_fde_t *F, void *data)
 117 {
 118         struct auth_client *auth = data;
 119         struct ident_query *query;
 120         char buf[IDENT_BUFSIZE + 1];    /* buffer to read auth reply into */
 121         ident_message message = REPORT_FAIL;
 122         char *s = NULL;
 123         char *t = NULL;
 124         ssize_t len;
 125         int count;
 126
 127         lrb_assert(auth != NULL);
 128         query = get_provider_data(auth, PROVIDER_IDENT);
 129         lrb_assert(query != NULL);
 130
 131         len = rb_read(F, buf, IDENT_BUFSIZE);
 132         if(len < 0 && rb_ignore_errno(errno))
 133         {
 134                 rb_setselect(F, RB_SELECT_READ, read_ident_reply, auth);
 135                 return;
 136         }
 137
 138         if(len > 0)
 139         {
 140                 if((s = get_valid_ident(buf)) != NULL)
 141                 {
 142                         t = auth->username;
 143
 144                         while (*s == '~' || *s == '^')
 145                                 s++;
 146
 147                         for (count = USERLEN; *s && count; s++)
 148                         {
 149                                 if(*s == '@' || *s == '\r' || *s == '\n')
 150                                         break;
 151
 152                                 if(*s != ' ' && *s != ':' && *s != '[')
 153                                 {
 154                                         *t++ = *s;
 155                                         count--;
 156                                 }
 157                         }
 158                         *t = '\0';
 159                 }
 160                 else
 161                         message = REPORT_INVALID;
 162         }
 163
 164         if(s == NULL)
 165                 client_fail(auth, message);
 166         else
 167                 client_success(auth);
 168 }
 169
 170 static void
 171 client_fail(struct auth_client *auth, ident_message report)
 172 {
 173         struct ident_query *query = get_provider_data(auth, PROVIDER_IDENT);
 174
 175         lrb_assert(query != NULL);
 176
 177         rb_strlcpy(auth->username, "*", sizeof(auth->username));
 178
 179         if(query->F != NULL)
 180                 rb_close(query->F);
 181
 182         rb_free(query);
 183         set_provider_data(auth, PROVIDER_IDENT, NULL);
 184         set_provider_timeout_absolute(auth, PROVIDER_IDENT, 0);
 185
 186         notice_client(auth->cid, messages[report]);
 187         provider_done(auth, PROVIDER_IDENT);
 188 }
 189
 190 static void
 191 client_success(struct auth_client *auth)
 192 {
 193         struct ident_query *query = get_provider_data(auth, PROVIDER_IDENT);
 194
 195         lrb_assert(query != NULL);
 196
 197         if(query->F != NULL)
 198                 rb_close(query->F);
 199
 200         rb_free(query);
 201         set_provider_data(auth, PROVIDER_IDENT, NULL);
 202         set_provider_timeout_absolute(auth, PROVIDER_IDENT, 0);
 203
 204         notice_client(auth->cid, messages[REPORT_FOUND]);
 205         provider_done(auth, PROVIDER_IDENT);
 206 }
 207
 208 /* get_valid_ident
 209  * parse ident query reply from identd server
 210  *
 211  * Taken from old s_auth.c --Elizafox
 212  *
 213  * Inputs       - pointer to ident buf
 214  * Outputs      - NULL if no valid ident found, otherwise pointer to name
 215  * Side effects - None
 216  */
 217 static char *
 218 get_valid_ident(char *buf)
 219 {
 220         int remp = 0;
 221         int locp = 0;
 222         char *colon1Ptr;
 223         char *colon2Ptr;
 224         char *colon3Ptr;
 225         char *commaPtr;
 226         char *remotePortString;
 227
 228         /* All this to get rid of a sscanf() fun. */
 229         remotePortString = buf;
 230
 231         colon1Ptr = strchr(remotePortString, ':');
 232         if(!colon1Ptr)
 233                 return NULL;
 234
 235         *colon1Ptr = '\0';
 236         colon1Ptr++;
 237         colon2Ptr = strchr(colon1Ptr, ':');
 238         if(!colon2Ptr)
 239                 return NULL;
 240
 241         *colon2Ptr = '\0';
 242         colon2Ptr++;
 243         commaPtr = strchr(remotePortString, ',');
 244
 245         if(!commaPtr)
 246                 return NULL;
 247
 248         *commaPtr = '\0';
 249         commaPtr++;
 250
 251         remp = atoi(remotePortString);
 252         if(!remp)
 253                 return NULL;
 254
 255         locp = atoi(commaPtr);
 256         if(!locp)
 257                 return NULL;
 258
 259         /* look for USERID bordered by first pair of colons */
 260         if(!strstr(colon1Ptr, "USERID"))
 261                 return NULL;
 262
 263         colon3Ptr = strchr(colon2Ptr, ':');
 264         if(!colon3Ptr)
 265                 return NULL;
 266
 267         *colon3Ptr = '\0';
 268         colon3Ptr++;
 269         return (colon3Ptr);
 270 }
 271
 272 static void
 273 ident_destroy(void)
 274 {
 275         struct auth_client *auth;
 276         rb_dictionary_iter iter;
 277
 278         /* Nuke all ident queries */
 279         RB_DICTIONARY_FOREACH(auth, &iter, auth_clients)
 280         {
 281                 if(get_provider_data(auth, PROVIDER_IDENT) != NULL)
 282                         client_fail(auth, REPORT_FAIL);
 283         }
 284 }
 285
 286 static bool
 287 ident_start(struct auth_client *auth)
 288 {
 289         struct ident_query *query = rb_malloc(sizeof(struct ident_query));
 290         struct rb_sockaddr_storage l_addr, c_addr;
 291         int family = GET_SS_FAMILY(&auth->c_addr);
 292
 293         lrb_assert(get_provider_data(auth, PROVIDER_IDENT) == NULL);
 294
 295         if(!ident_enable)
 296         {
 297                 rb_free(query);
 298                 notice_client(auth->cid, messages[REPORT_DISABLED]);
 299                 set_provider_done(auth, PROVIDER_IDENT);
 300                 return true;
 301         }
 302
 303         notice_client(auth->cid, messages[REPORT_LOOKUP]);
 304
 305         set_provider_data(auth, PROVIDER_IDENT, query);
 306         set_provider_timeout_relative(auth, PROVIDER_IDENT, ident_timeout);
 307
 308         if((query->F = rb_socket(family, SOCK_STREAM, 0, "ident")) == NULL)
 309         {
 310                 warn_opers(L_DEBUG, "Could not create ident socket: %s", strerror(errno));
 311                 client_fail(auth, REPORT_FAIL);
 312                 return true;    /* Not a fatal error */
 313         }
 314
 315         /* Build sockaddr_storages for rb_connect_tcp below */
 316         l_addr = auth->l_addr;
 317         c_addr = auth->c_addr;
 318
 319         SET_SS_PORT(&l_addr, 0);
 320         SET_SS_PORT(&c_addr, htons(113));
 321
 322         rb_connect_tcp(query->F, (struct sockaddr *)&c_addr,
 323                         (struct sockaddr *)&l_addr,
 324                         GET_SS_LEN(&l_addr), ident_connected,
 325                         auth, ident_timeout);
 326
 327         set_provider_running(auth, PROVIDER_IDENT);
 328
 329         return true;
 330 }
 331
 332 static void
 333 ident_cancel(struct auth_client *auth)
 334 {
 335         struct ident_query *query = get_provider_data(auth, PROVIDER_IDENT);
 336
 337         if(query != NULL)
 338                 client_fail(auth, REPORT_FAIL);
 339 }
 340
 341 static void
 342 add_conf_ident_timeout(const char *key __unused, int parc __unused, const char **parv)
 343 {
 344         int timeout = atoi(parv[0]);
 345
 346         if(timeout < 0)
 347         {
 348                 warn_opers(L_CRIT, "Ident: ident timeout < 0 (value: %d)", timeout);
 349                 exit(EX_PROVIDER_ERROR);
 350         }
 351
 352         ident_timeout = timeout;
 353 }
 354
 355 static void
 356 set_ident_enabled(const char *key __unused, int parc __unused, const char **parv)
 357 {
 358         ident_enable = (*parv[0] == '1');
 359 }
 360
 361 struct auth_opts_handler ident_options[] =
 362 {
 363         { "ident_timeout", 1, add_conf_ident_timeout },
 364         { "ident_enabled", 1, set_ident_enabled },
 365         { NULL, 0, NULL },
 366 };
 367
 368
 369 struct auth_provider ident_provider =
 370 {
 371         .id = PROVIDER_IDENT,
 372         .start = ident_start,
 373         .destroy = ident_destroy,
 374         .cancel = ident_cancel,
 375         .timeout = ident_cancel,
 376         .opt_handlers = ident_options,
 377 };