mdw@git.distorted.org.uk Git - fwd/blob - identify.c

   1 /* -*-c-*-
   2  *
   3  * $Id: identify.c,v 1.10 2003/11/29 22:15:19 mdw Exp $
   4  *
   5  * Identifies and logs the client of a connection
   6  *
   7  * (c) 1999 Straylight/Edgeware
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of the `fw' port forwarder.
  13  *
  14  * `fw' is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * `fw' is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  *
  24  * You should have received a copy of the GNU General Public License
  25  * along with `fw'; if not, write to the Free Software Foundation,
  26  * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  27  */
  28
  29 /*----- Revision history --------------------------------------------------*
  30  *
  31  * $Log: identify.c,v $
  32  * Revision 1.10  2003/11/29 22:15:19  mdw
  33  * And a typo fix.
  34  *
  35  * Revision 1.9  2003/11/29 22:13:43  mdw
  36  * Fix bug in identification timout handling.
  37  *
  38  * Revision 1.8  2003/11/29 20:36:07  mdw
  39  * Privileged outgoing connections.
  40  *
  41  * Revision 1.7  2002/02/22 23:43:32  mdw
  42  * Call @xfree@ rather than @free@.
  43  *
  44  * Revision 1.6  2001/06/22 19:36:49  mdw
  45  * Enlarge the identity buffer.
  46  *
  47  * Revision 1.5  1999/10/10 16:45:34  mdw
  48  * Modified to use new mLib resolver and ident client.
  49  *
  50  * Revision 1.4  1999/07/27 18:30:53  mdw
  51  * Various minor portability fixes.
  52  *
  53  * Revision 1.3  1999/07/26 23:26:21  mdw
  54  * Minor modifications for new design.
  55  *
  56  * Revision 1.2  1999/07/03 13:56:59  mdw
  57  * Log connections to syslog or stderr as appropriate.
  58  *
  59  * Revision 1.1.1.1  1999/07/01 08:56:23  mdw
  60  * Initial revision.
  61  *
  62  */
  63
  64 /*----- Header files ------------------------------------------------------*/
  65
  66 #include "config.h"
  67
  68 #include <errno.h>
  69 #include <stdio.h>
  70 #include <stdlib.h>
  71 #include <string.h>
  72 #include <time.h>
  73
  74 #include <sys/types.h>
  75 #include <sys/time.h>
  76 #include <unistd.h>
  77 #include <syslog.h>
  78
  79 #include <sys/socket.h>
  80 #include <netinet/in.h>
  81 #include <arpa/inet.h>
  82 #include <netdb.h>
  83
  84 #include <mLib/alloc.h>
  85 #include <mLib/bres.h>
  86 #include <mLib/conn.h>
  87 #include <mLib/dstr.h>
  88 #include <mLib/ident.h>
  89 #include <mLib/report.h>
  90 #include <mLib/sel.h>
  91 #include <mLib/selbuf.h>
  92 #include <mLib/str.h>
  93
  94 #include "fw.h"
  95 #include "identify.h"
  96
  97 /*----- Magic numbers -----------------------------------------------------*/
  98
  99 #define TIMEOUT 15                      /* Seconds to wait for answers */
 100
 101 /*----- Data structures ---------------------------------------------------*/
 102
 103 /* --- Structure to track the progress of an identification --- */
 104
 105 typedef struct id {
 106   id_req q;                             /* Copy of client's request block */
 107   time_t when;                          /* When the connection occurred */
 108   conn c;                               /* Connection selector */
 109   unsigned state;                       /* Current state of the world */
 110   sel_timer t;                          /* Timeout selector */
 111   bres_client r;                        /* Backgd resolver client block */
 112   ident_request i;                      /* Ident client block */
 113   char host[128];                       /* Resolved hostname */
 114   char user[64];                        /* Authenticated client user */
 115 } id;
 116
 117 #define S_HOST 1u                       /* Read the hostname from resolver */
 118 #define S_USER 2u                       /* Read the username from RFC931 */
 119 #define S_TIMER 4u                      /* Timeout has completed */
 120
 121 /*----- Main code ---------------------------------------------------------*/
 122
 123 /* --- @id_done@ --- *
 124  *
 125  * Arguments:   @id *i@ = pointer to identification block
 126  *
 127  * Returns:     ---
 128  *
 129  * Use:         Finishes with an identification block.
 130  */
 131
 132 static void id_done(id *i)
 133 {
 134   /* --- Close down the various dependent bits --- */
 135
 136   if (!(i->state & S_HOST))
 137     bres_abort(&i->r);
 138   if (!(i->state & S_USER))
 139     ident_abort(&i->i);
 140   if (!(i->state & S_TIMER))
 141     sel_rmtimer(&i->t);
 142
 143   /* --- Report the final result --- */
 144
 145   fw_log(i->when, "[%s] %s from %s@%s [%s:%u]",
 146          i->q.desc, i->q.act,
 147          i->user, i->host,
 148          inet_ntoa(i->q.rsin.sin_addr), (unsigned)ntohs(i->q.rsin.sin_port));
 149
 150   /* --- Dispose of the block --- */
 151
 152   REFFD_DEC(i->q.r);
 153   xfree(i);
 154 }
 155
 156 /* --- @id_res@ --- *
 157  *
 158  * Arguments:   @struct hostent *h@ = name of the resolved host
 159  *              @void *vp@ = pointer to identification block
 160  *
 161  * Returns:     ---
 162  *
 163  * Use:         Responds to a completed reverse name resolution.
 164  */
 165
 166 static void id_res(struct hostent *h, void *vp)
 167 {
 168   id *i = vp;
 169   if (h)
 170     str_sanitize(i->host, h->h_name, sizeof(i->host));
 171   i->state |= S_HOST;
 172   if (i->state & S_USER)
 173     id_done(i);
 174 }
 175
 176 /* --- @id_ident@ --- *
 177  *
 178  * Arguments:   @ident_reply *i@ = pointer to string read from server
 179  *              @void *vp@ = pointer to identification block
 180  *
 181  * Returns:     ---
 182  *
 183  * Use:         Responds to a line read from the remote RFC931 server.
 184  */
 185
 186 static void id_ident(ident_reply *ir, void *vp)
 187 {
 188   id *i = vp;
 189
 190   /* --- Read the information from the client --- */
 191
 192   if (ir && ir->type == IDENT_USERID)
 193     str_sanitize(i->user, ir->u.userid.user, sizeof(i->user));
 194
 195   /* --- Maybe finish off this identification --- */
 196
 197   i->state |= S_USER;
 198   if (i->state & S_HOST)
 199     id_done(i);
 200 }
 201
 202 /* --- @id_timer@ --- *
 203  *
 204  * Arguments:   @struct timeval *tv@ = pointer to the current time
 205  *              @void *vp@ = pointer to identification block
 206  *
 207  * Returns:     ---
 208  *
 209  * Use:         Times an identification job out.
 210  */
 211
 212 static void id_timer(struct timeval *tv, void *vp)
 213 {
 214   id *i = vp;
 215   i->state |= S_TIMER;
 216   id_done(i);
 217 }
 218
 219 /* --- @identify@ --- *
 220  *
 221  * Arguments:   @const id_req *q@ = pointer to request block
 222  *
 223  * Returns:     ---
 224  *
 225  * Use:         Starts a background ident lookup and reverse-resolve job
 226  *              which will, eventually, report a message to the system log.
 227  */
 228
 229 void identify(const id_req *q)
 230 {
 231   id *i;
 232
 233   /* --- Initialize the block with stuff --- */
 234
 235   i = xmalloc(sizeof(*i));
 236   i->q = *q;
 237   REFFD_INC(i->q.r);
 238
 239   str_sanitize(i->host, inet_ntoa(q->rsin.sin_addr), sizeof(i->host));
 240   strcpy(i->user, "<ANONYMOUS>");
 241   i->state = 0;
 242   i->when = time(0);
 243
 244   /* --- Set up the connection to the identity server --- */
 245
 246   ident(&i->i, sel, &q->lsin, &q->rsin, id_ident, i);
 247
 248   /* --- Set up the name resolver --- */
 249
 250   bres_byaddr(&i->r, q->rsin.sin_addr, id_res, i);
 251
 252   /* --- Set up the time limiter --- */
 253
 254   {
 255     struct timeval tv;
 256     gettimeofday(&tv, 0);
 257     tv.tv_sec += TIMEOUT;
 258     sel_addtimer(sel, &i->t, &tv, id_timer, i);
 259   }
 260 }
 261
 262 /*----- That's all, folks -------------------------------------------------*/