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

   1 /* -*-c-*-
   2  *
   3  * $Id: rule.c,v 1.6 1998/04/23 13:27:31 mdw Exp $
   4  *
   5  * Managing rule sets
   6  *
   7  * (c) 1998 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 1.6  1998/04/23 13:27:31  mdw
  33  * Export structure of the rule list, for `bcquery's benefit.
  34  *
  35  * Revision 1.5  1998/01/12 16:46:25  mdw
  36  * Fix copyright date.
  37  *
  38  * Revision 1.4  1997/09/17  10:27:17  mdw
  39  * Use rewritten class handler.
  40  *
  41  * Revision 1.3  1997/08/20  16:22:36  mdw
  42  * Rename `rule_reinit' to `rule_end' for more sensible restart.  Don't try
  43  * to trace when tracing's turned off.
  44  *
  45  * Revision 1.2  1997/08/04 10:24:25  mdw
  46  * Sources placed under CVS control.
  47  *
  48  * Revision 1.1  1997/07/21  13:47:45  mdw
  49  * Initial revision
  50  *
  51  */
  52
  53 /*----- Header files ------------------------------------------------------*/
  54
  55 /* --- ANSI headers --- */
  56
  57 #include <stdio.h>
  58 #include <stdlib.h>
  59 #include <string.h>
  60
  61 /* --- Unix headers --- */
  62
  63 #include <sys/types.h>
  64 #include <sys/socket.h>
  65 #include <netinet/in.h>
  66 #include <arpa/inet.h>
  67 #include <netdb.h>
  68 #include <unistd.h>
  69
  70 /* --- Local headers --- */
  71
  72 #include "become.h"
  73 #include "class.h"
  74 #include "rule.h"
  75 #include "userdb.h"
  76 #include "utils.h"
  77
  78 /*----- Static variables --------------------------------------------------*/
  79
  80 static rule *rule__list;                /* List of rules */
  81 static rule *rule__tail;                /* Pointer to last rule item */
  82
  83 /*----- Main code ---------------------------------------------------------*/
  84
  85 /* --- @rule_init@ --- *
  86  *
  87  * Arguments:   ---
  88  *
  89  * Returns:     ---
  90  *
  91  * Use:         Intialises the rule database.
  92  */
  93
  94 void rule_init(void)
  95 {
  96   rule__list = 0;
  97   rule__tail = (rule *)&rule__list;
  98 }
  99
 100 /* --- @rule_end@ --- *
 101  *
 102  * Arguments:   ---
 103  *
 104  * Returns:     ---
 105  *
 106  * Use:         Empties the rule database.
 107  */
 108
 109 void rule_end(void)
 110 {
 111   rule *r = rule__list;
 112   rule *rr;
 113
 114   while (r) {
 115     rr = r->next;
 116     class_dec(r->host);
 117     class_dec(r->from);
 118     class_dec(r->to);
 119     class_dec(r->cmd);
 120     free(r);
 121     r = rr;
 122   }
 123 }
 124
 125 /* --- @rule_list@ --- *
 126  *
 127  * Arguments:   ---
 128  *
 129  * Returns:     The list of rules.
 130  *
 131  * Use:         Returns the address of the first node in the rule list.
 132  */
 133
 134 rule *rule_list(void)
 135 {
 136   return (rule__list);
 137 }
 138
 139 /* --- @rule_add@ --- *
 140  *
 141  * Arguments:   @class_node *host@ = class of hosts this rule applies to
 142  *              @class_node *from@ = class of users allowed to change
 143  *              @class_node *to@ = class of users allowed to be changed to
 144  *              @class_node *cmd@ = class of commands allowed
 145  *
 146  * Returns:     ---
 147  *
 148  * Use:         Registers another rule.
 149  */
 150
 151 void rule_add(class_node *host, class_node *from,
 152               class_node *to, class_node *cmd)
 153 {
 154   rule *r = xmalloc(sizeof(*r));
 155
 156   r->host = host;
 157   r->from = from;
 158   r->to = to;
 159   r->cmd = cmd;
 160   r->next = 0;
 161   rule__tail->next = r;
 162   rule__tail = r;
 163 }
 164
 165 /* --- @rule_check@ --- *
 166  *
 167  * Arguments:   @request *r@ = pointer to a request block
 168  *
 169  * Returns:     Zero if disallowed, nonzero if allowed.
 170  *
 171  * Use:         Checks a request to see if it's allowed.
 172  */
 173
 174 int rule_check(request *r)
 175 {
 176   rule *rr;
 177
 178   /* --- Trace out the request we're checking --- */
 179
 180   IF_TRACING(TRACE_CHECK, {
 181     struct passwd *pw_from = userdb_userById(r->from);
 182     struct passwd *pw_to = userdb_userById(r->to);
 183     struct hostent *h = gethostbyaddr((char *)&r->host, sizeof(r->host),
 184                                       AF_INET);
 185
 186     trace(TRACE_CHECK, "check: request from %s (%li) to become %s (%li)",
 187           pw_from ? pw_from->pw_name : "<unknown>", (long)r->from,
 188           pw_to ? pw_to->pw_name : "<unknown>", (long)r->to);
 189     trace(TRACE_CHECK, "check: ... at %s (%s) for `%s'",
 190           h ? h->h_name : "<unknown>", inet_ntoa(r->host), r->cmd);
 191   })
 192
 193   /* --- Search the rule list --- */
 194
 195   for (rr = rule__list; rr; rr = rr->next) {
 196
 197     /* --- Trace out the rule --- */
 198
 199     IF_TRACING(TRACE_RULE, {
 200       trace(TRACE_RULE, "rule: check against rule...");
 201       trace(TRACE_RULE, "rule:   from"); class_dump(rr->from, 2);
 202       trace(TRACE_RULE, "rule:   to"); class_dump(rr->to, 2);
 203       trace(TRACE_RULE, "rule:   cmd"); class_dump(rr->cmd, 2);
 204       trace(TRACE_RULE, "rule:   host"); class_dump(rr->host, 2);
 205     })
 206
 207     /* --- Check the rule --- */
 208
 209     if (class_matchUser(rr->from, r->from) &&
 210         class_matchUser(rr->to, r->to) &&
 211         class_matchCommand(rr->cmd, r->cmd) &&
 212         class_matchHost(rr->host, r->host)) {
 213       T( trace(TRACE_CHECK, "check: rule matched -- granting permission"); )
 214       return (1);
 215     }
 216   }
 217
 218   /* --- Failed to match --- */
 219
 220   T( trace(TRACE_CHECK, "check: no rules matched -- permission denied"); )
 221   return (0);
 222 }
 223
 224 /* --- @rule_dump@ --- *
 225  *
 226  * Arguments:   ---
 227  *
 228  * Returns:     ---
 229  *
 230  * Use:         Dumps a map of the current ruleset to the trace output.
 231  */
 232
 233 void rule_dump(void)
 234 {
 235 #ifdef TRACING
 236   rule *rr = rule__list;
 237
 238   trace(TRACE_RULE, "rule: dumping rules");
 239   while (rr) {
 240     trace(TRACE_RULE, "rule: rule dump...");
 241     trace(TRACE_RULE, "rule:   from"); class_dump(rr->from, 2);
 242     trace(TRACE_RULE, "rule:   to"); class_dump(rr->to, 2);
 243     trace(TRACE_RULE, "rule:   cmd"); class_dump(rr->cmd, 2);
 244     trace(TRACE_RULE, "rule:   host"); class_dump(rr->host, 2);
 245     rr = rr->next;
 246   }
 247   trace(TRACE_RULE, "rule: dump finished");
 248 #endif
 249 }
 250
 251 /*----- That's all, folks -------------------------------------------------*/