mdw@git.distorted.org.uk Git - become/blob - src/rule.c

   1 /* -*-c-*-
   2  *
   3  * $Id: rule.c,v 1.4 1997/09/17 10:27:17 mdw Exp $
   4  *
   5  * Managing rule sets
   6  *
   7  * (c) 1997 EBI
   8  */
   9
  10 /*----- Licensing notice --------------------------------------------------*
  11  *
  12  * This file is part of `become'
  13  *
  14  * `Become' 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  * `Become' 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 `become'; 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: rule.c,v $
  32  * Revision 1.4  1997/09/17 10:27:17  mdw
  33  * Use rewritten class handler.
  34  *
  35  * Revision 1.3  1997/08/20  16:22:36  mdw
  36  * Rename `rule_reinit' to `rule_end' for more sensible restart.  Don't try
  37  * to trace when tracing's turned off.
  38  *
  39  * Revision 1.2  1997/08/04 10:24:25  mdw
  40  * Sources placed under CVS control.
  41  *
  42  * Revision 1.1  1997/07/21  13:47:45  mdw
  43  * Initial revision
  44  *
  45  */
  46
  47 /*----- Header files ------------------------------------------------------*/
  48
  49 /* --- ANSI headers --- */
  50
  51 #include <stdio.h>
  52 #include <stdlib.h>
  53 #include <string.h>
  54
  55 /* --- Unix headers --- */
  56
  57 #include <sys/types.h>
  58 #include <sys/socket.h>
  59 #include <netinet/in.h>
  60 #include <arpa/inet.h>
  61 #include <netdb.h>
  62 #include <unistd.h>
  63
  64 /* --- Local headers --- */
  65
  66 #include "become.h"
  67 #include "class.h"
  68 #include "rule.h"
  69 #include "userdb.h"
  70 #include "utils.h"
  71
  72 /*----- Type definitions --------------------------------------------------*/
  73
  74 /* --- Rule block --- */
  75
  76 typedef struct rule {
  77   struct rule *next;                    /* Next rule in the list */
  78   class_node *host;                     /* Hosts this rule applies to */
  79   class_node *from;                     /* From users in this class */
  80   class_node *to;                               /* To users in this class */
  81   class_node *cmd;                      /* To run commands in this class */
  82 } rule;
  83
  84 /*----- Static variables --------------------------------------------------*/
  85
  86 static rule *rule__list;                /* List of rules */
  87 static rule *rule__tail;                /* Pointer to last rule item */
  88
  89 /*----- Main code ---------------------------------------------------------*/
  90
  91 /* --- @rule_init@ --- *
  92  *
  93  * Arguments:   ---
  94  *
  95  * Returns:     ---
  96  *
  97  * Use:         Intialises the rule database.
  98  */
  99
 100 void rule_init(void)
 101 {
 102   rule__list = 0;
 103   rule__tail = (rule *)&rule__list;
 104 }
 105
 106 /* --- @rule_end@ --- *
 107  *
 108  * Arguments:   ---
 109  *
 110  * Returns:     ---
 111  *
 112  * Use:         Empties the rule database.
 113  */
 114
 115 void rule_end(void)
 116 {
 117   rule *r = rule__list;
 118   rule *rr;
 119
 120   while (r) {
 121     rr = r->next;
 122     class_dec(r->host);
 123     class_dec(r->from);
 124     class_dec(r->to);
 125     class_dec(r->cmd);
 126     free(r);
 127     r = rr;
 128   }
 129 }
 130
 131 /* --- @rule_add@ --- *
 132  *
 133  * Arguments:   @class_node *host@ = class of hosts this rule applies to
 134  *              @class_node *from@ = class of users allowed to change
 135  *              @class_node *to@ = class of users allowed to be changed to
 136  *              @class_node *cmd@ = class of commands allowed
 137  *
 138  * Returns:     ---
 139  *
 140  * Use:         Registers another rule.
 141  */
 142
 143 void rule_add(class_node *host, class_node *from, class_node *to, class_node *cmd)
 144 {
 145   rule *r = xmalloc(sizeof(*r));
 146
 147   r->host = host;
 148   r->from = from;
 149   r->to = to;
 150   r->cmd = cmd;
 151   r->next = 0;
 152   rule__tail->next = r;
 153   rule__tail = r;
 154 }
 155
 156 /* --- @rule_check@ --- *
 157  *
 158  * Arguments:   @request *r@ = pointer to a request block
 159  *
 160  * Returns:     Zero if disallowed, nonzero if allowed.
 161  *
 162  * Use:         Checks a request to see if it's allowed.
 163  */
 164
 165 int rule_check(request *r)
 166 {
 167   rule *rr;
 168
 169   /* --- Trace out the request we're checking --- */
 170
 171   IF_TRACING(TRACE_CHECK, {
 172     struct passwd *pw_from = userdb_userById(r->from);
 173     struct passwd *pw_to = userdb_userById(r->to);
 174     struct hostent *h = gethostbyaddr((char *)&r->host, sizeof(r->host),
 175                                       AF_INET);
 176
 177     trace(TRACE_CHECK, "check: request from %s (%li) to become %s (%li)",
 178           pw_from ? pw_from->pw_name : "<unknown>", (long)r->from,
 179           pw_to ? pw_to->pw_name : "<unknown>", (long)r->to);
 180     trace(TRACE_CHECK, "check: ... at %s (%s) for `%s'",
 181           h ? h->h_name : "<unknown>", inet_ntoa(r->host), r->cmd);
 182   })
 183
 184   /* --- Search the rule list --- */
 185
 186   for (rr = rule__list; rr; rr = rr->next) {
 187
 188     /* --- Trace out the rule --- */
 189
 190     IF_TRACING(TRACE_RULE, {
 191       trace(TRACE_RULE, "rule: check against rule...");
 192       trace(TRACE_RULE, "rule:   from"); class_dump(rr->from, 2);
 193       trace(TRACE_RULE, "rule:   to"); class_dump(rr->to, 2);
 194       trace(TRACE_RULE, "rule:   cmd"); class_dump(rr->cmd, 2);
 195       trace(TRACE_RULE, "rule:   host"); class_dump(rr->host, 2);
 196     })
 197
 198     /* --- Check the rule --- */
 199
 200     if (class_matchUser(rr->from, r->from) &&
 201         class_matchUser(rr->to, r->to) &&
 202         class_matchCommand(rr->cmd, r->cmd) &&
 203         class_matchHost(rr->host, r->host)) {
 204       T( trace(TRACE_CHECK, "check: rule matched -- granting permission"); )
 205       return (1);
 206     }
 207   }
 208
 209   /* --- Failed to match --- */
 210
 211   T( trace(TRACE_CHECK, "check: no rules matched -- permission denied"); )
 212   return (0);
 213 }
 214
 215 /* --- @rule_dump@ --- *
 216  *
 217  * Arguments:   ---
 218  *
 219  * Returns:     ---
 220  *
 221  * Use:         Dumps a map of the current ruleset to the trace output.
 222  */
 223
 224 void rule_dump(void)
 225 {
 226 #ifdef TRACING
 227   rule *rr = rule__list;
 228
 229   trace(TRACE_RULE, "rule: dumping rules");
 230   while (rr) {
 231     trace(TRACE_RULE, "rule: rule dump...");
 232     trace(TRACE_RULE, "rule:   from"); class_dump(rr->from, 2);
 233     trace(TRACE_RULE, "rule:   to"); class_dump(rr->to, 2);
 234     trace(TRACE_RULE, "rule:   cmd"); class_dump(rr->cmd, 2);
 235     trace(TRACE_RULE, "rule:   host"); class_dump(rr->host, 2);
 236     rr = rr->next;
 237   }
 238   trace(TRACE_RULE, "rule: dump finished");
 239 #endif
 240 }
 241
 242 /*----- That's all, folks -------------------------------------------------*/