| 1 | /* -*-c-*- |
| 2 | * |
| 3 | * $Id: acl.c,v 1.5 2004/04/08 01:36:25 mdw Exp $ |
| 4 | * |
| 5 | * Access control list handling |
| 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 | /*----- Header files ------------------------------------------------------*/ |
| 30 | |
| 31 | #include "config.h" |
| 32 | |
| 33 | #include <errno.h> |
| 34 | #include <stdio.h> |
| 35 | #include <stdlib.h> |
| 36 | #include <string.h> |
| 37 | |
| 38 | #include <sys/types.h> |
| 39 | #include <unistd.h> |
| 40 | |
| 41 | #include <sys/socket.h> |
| 42 | #include <netinet/in.h> |
| 43 | #include <arpa/inet.h> |
| 44 | #include <netdb.h> |
| 45 | |
| 46 | #include <mLib/sub.h> |
| 47 | |
| 48 | #include "acl.h" |
| 49 | |
| 50 | /*----- Main code ---------------------------------------------------------*/ |
| 51 | |
| 52 | /* --- @acl_addhost@ --- * |
| 53 | * |
| 54 | * Arguments: @acl_entry ***a@ = address of pointer to list tail |
| 55 | * @unsigned act@ = what to do with matching addresses |
| 56 | * @struct in_addr addr, mask@ = address and mask to match |
| 57 | * |
| 58 | * Returns: --- |
| 59 | * |
| 60 | * Use: Adds a host-authentication entry to the end of an access |
| 61 | * control list. |
| 62 | */ |
| 63 | |
| 64 | static int acl_checkhost(void *aa, struct in_addr addr, unsigned port) |
| 65 | { |
| 66 | acl_host *a = aa; |
| 67 | return ((addr.s_addr & a->mask.s_addr) == a->addr.s_addr); |
| 68 | } |
| 69 | |
| 70 | static void acl_dumphost(void *aa, FILE *fp) |
| 71 | { |
| 72 | acl_host *a = aa; |
| 73 | |
| 74 | fputs("from ", fp); |
| 75 | fputs(inet_ntoa(a->addr), fp); |
| 76 | fputc('/', fp); |
| 77 | fputs(inet_ntoa(a->mask), fp); |
| 78 | } |
| 79 | |
| 80 | static void acl_freehost(void *aa) |
| 81 | { |
| 82 | acl_host *a = aa; |
| 83 | DESTROY(a); |
| 84 | } |
| 85 | |
| 86 | static const acl_ops acl_hostops = { |
| 87 | acl_checkhost, acl_dumphost, acl_freehost |
| 88 | }; |
| 89 | |
| 90 | void acl_addhost(acl_entry ***a, unsigned act, |
| 91 | struct in_addr addr, struct in_addr mask) |
| 92 | { |
| 93 | acl_host *aa = CREATE(acl_host); |
| 94 | aa->a.next = 0; |
| 95 | aa->a.ops = &acl_hostops; |
| 96 | aa->a.act = act; |
| 97 | aa->addr.s_addr = addr.s_addr & mask.s_addr; |
| 98 | aa->mask = mask; |
| 99 | **a = &aa->a; |
| 100 | *a = &aa->a.next; |
| 101 | } |
| 102 | |
| 103 | /* --- @acl_addpriv@ --- * |
| 104 | * |
| 105 | * Arguments: @acl_entry ***a@ = address of pointer to list tail |
| 106 | * @unsigned act@ = what to do with matching addresses |
| 107 | * |
| 108 | * Returns: --- |
| 109 | * |
| 110 | * Use: Adds a privileged-port check to the end of an access control |
| 111 | * list. |
| 112 | */ |
| 113 | |
| 114 | static int acl_checkpriv(void *aa, struct in_addr addr, unsigned port) |
| 115 | { |
| 116 | return (port < 1024); |
| 117 | } |
| 118 | |
| 119 | static void acl_dumppriv(void *aa, FILE *fp) |
| 120 | { |
| 121 | fputs("from privileged ports", fp); |
| 122 | } |
| 123 | |
| 124 | static void acl_freepriv(void *aa) |
| 125 | { |
| 126 | acl_entry *a = aa; |
| 127 | DESTROY(a); |
| 128 | } |
| 129 | |
| 130 | static const acl_ops acl_privops = { |
| 131 | acl_checkpriv, acl_dumppriv, acl_freepriv |
| 132 | }; |
| 133 | |
| 134 | void acl_addpriv(acl_entry ***a, unsigned act) |
| 135 | { |
| 136 | acl_entry *aa = CREATE(acl_entry); |
| 137 | aa->next = 0; |
| 138 | aa->ops = &acl_privops; |
| 139 | aa->act = act; |
| 140 | **a = aa; |
| 141 | *a = &aa->next; |
| 142 | } |
| 143 | |
| 144 | /* --- @acl_check@ --- * |
| 145 | * |
| 146 | * Arguments: @acl_entry *a@ = pointer to ACL to check against |
| 147 | * @struct in_addr addr@ = address to check |
| 148 | * @unsigned port@ = port number to check |
| 149 | * @int *act@ = verdict (should initially be @ACT_ALLOW@) |
| 150 | * |
| 151 | * Returns: Zero if undecided, nonzero if a rule matched. |
| 152 | * |
| 153 | * Use: Checks an address against an ACL. |
| 154 | */ |
| 155 | |
| 156 | int acl_check(acl_entry *a, struct in_addr addr, unsigned port, int *act) |
| 157 | { |
| 158 | for (; a; a = a->next) { |
| 159 | if (a->ops->check(a, addr, port)) { |
| 160 | *act = a->act & ACL_PERM; |
| 161 | return (1); |
| 162 | } |
| 163 | *act = (a->act & ACL_PERM) ^ 1; |
| 164 | } |
| 165 | return (0); |
| 166 | } |
| 167 | |
| 168 | /* --- @acl_dump@ --- * |
| 169 | * |
| 170 | * Arguments: @acl_entry *a@ = pointer to ACL to dump |
| 171 | * @FILE *fp@ = pointer to stream to dump on |
| 172 | * |
| 173 | * Returns: --- |
| 174 | * |
| 175 | * Use: Dumps an access control list to an output stream. |
| 176 | */ |
| 177 | |
| 178 | void acl_dump(acl_entry *a, FILE *fp) |
| 179 | { |
| 180 | for (; a; a = a->next) { |
| 181 | fprintf(fp, " %s ", |
| 182 | (a->act & ACL_PERM) == ACL_ALLOW ? "allow" : "deny"); |
| 183 | a->ops->dump(a, fp); |
| 184 | fputc('\n', fp); |
| 185 | } |
| 186 | } |
| 187 | |
| 188 | /* --- @acl_free@ --- * |
| 189 | * |
| 190 | * Arguments: @acl_entry *a@ = pointer to a list of ACLs |
| 191 | * |
| 192 | * Returns: --- |
| 193 | * |
| 194 | * Use: Frees all of the memory used by an ACL. |
| 195 | */ |
| 196 | |
| 197 | void acl_free(acl_entry *a) |
| 198 | { |
| 199 | while (a) { |
| 200 | acl_entry *aa = a; |
| 201 | a = a->next; |
| 202 | aa->ops->free(aa); |
| 203 | } |
| 204 | } |
| 205 | |
| 206 | /*----- That's all, folks -------------------------------------------------*/ |