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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: acl.c,v 1.4 2003/11/25 14:08:23 mdw Exp $ |
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4 | * |
5 | * Access control list handling |
6 | * |
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7 | * (c) 1999 Straylight/Edgeware |
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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: acl.c,v $ |
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32 | * Revision 1.4 2003/11/25 14:08:23 mdw |
33 | * Debianization. Socket target options. Internet binding. |
34 | * |
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35 | * Revision 1.3 1999/07/27 18:30:53 mdw |
36 | * Various minor portability fixes. |
37 | * |
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38 | * Revision 1.2 1999/07/26 23:28:15 mdw |
39 | * Minor modifications for new design. |
40 | * |
41 | * Revision 1.1.1.1 1999/07/01 08:56:23 mdw |
42 | * Initial revision. |
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43 | * |
44 | */ |
45 | |
46 | /*----- Header files ------------------------------------------------------*/ |
47 | |
48 | #include "config.h" |
49 | |
50 | #include <errno.h> |
51 | #include <stdio.h> |
52 | #include <stdlib.h> |
53 | #include <string.h> |
54 | |
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55 | #include <sys/types.h> |
56 | #include <unistd.h> |
57 | |
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58 | #include <sys/socket.h> |
59 | #include <netinet/in.h> |
60 | #include <arpa/inet.h> |
61 | #include <netdb.h> |
62 | |
63 | #include <mLib/sub.h> |
64 | |
65 | #include "acl.h" |
66 | |
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67 | /*----- Main code ---------------------------------------------------------*/ |
68 | |
69 | /* --- @acl_addhost@ --- * |
70 | * |
71 | * Arguments: @acl_entry ***a@ = address of pointer to list tail |
72 | * @unsigned act@ = what to do with matching addresses |
73 | * @struct in_addr addr, mask@ = address and mask to match |
74 | * |
75 | * Returns: --- |
76 | * |
77 | * Use: Adds a host-authentication entry to the end of an access |
78 | * control list. |
79 | */ |
80 | |
81 | static int acl_checkhost(void *aa, struct in_addr addr, unsigned port) |
82 | { |
83 | acl_host *a = aa; |
84 | return ((addr.s_addr & a->mask.s_addr) == a->addr.s_addr); |
85 | } |
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86 | |
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87 | static void acl_dumphost(void *aa, FILE *fp) |
88 | { |
89 | acl_host *a = aa; |
90 | |
91 | fputs("from ", fp); |
92 | fputs(inet_ntoa(a->addr), fp); |
93 | fputc('/', fp); |
94 | fputs(inet_ntoa(a->mask), fp); |
95 | } |
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96 | |
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97 | static void acl_freehost(void *aa) |
98 | { |
99 | acl_host *a = aa; |
100 | DESTROY(a); |
101 | } |
102 | |
103 | static const acl_ops acl_hostops = { |
104 | acl_checkhost, acl_dumphost, acl_freehost |
105 | }; |
106 | |
107 | void acl_addhost(acl_entry ***a, unsigned act, |
108 | struct in_addr addr, struct in_addr mask) |
109 | { |
110 | acl_host *aa = CREATE(acl_host); |
111 | aa->a.next = 0; |
112 | aa->a.ops = &acl_hostops; |
113 | aa->a.act = act; |
114 | aa->addr.s_addr = addr.s_addr & mask.s_addr; |
115 | aa->mask = mask; |
116 | **a = &aa->a; |
117 | *a = &aa->a.next; |
118 | } |
119 | |
120 | /* --- @acl_addpriv@ --- * |
121 | * |
122 | * Arguments: @acl_entry ***a@ = address of pointer to list tail |
123 | * @unsigned act@ = what to do with matching addresses |
124 | * |
125 | * Returns: --- |
126 | * |
127 | * Use: Adds a privileged-port check to the end of an access control |
128 | * list. |
129 | */ |
130 | |
131 | static int acl_checkpriv(void *aa, struct in_addr addr, unsigned port) |
132 | { |
133 | return (port < 1024); |
134 | } |
135 | |
136 | static void acl_dumppriv(void *aa, FILE *fp) |
137 | { |
138 | fputs("from privileged ports", fp); |
139 | } |
140 | |
141 | static void acl_freepriv(void *aa) |
142 | { |
143 | acl_entry *a = aa; |
144 | DESTROY(a); |
145 | } |
146 | |
147 | static const acl_ops acl_privops = { |
148 | acl_checkpriv, acl_dumppriv, acl_freepriv |
149 | }; |
150 | |
151 | void acl_addpriv(acl_entry ***a, unsigned act) |
152 | { |
153 | acl_entry *aa = CREATE(acl_entry); |
154 | aa->next = 0; |
155 | aa->ops = &acl_privops; |
156 | aa->act = act; |
157 | **a = aa; |
158 | *a = &aa->next; |
159 | } |
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160 | |
161 | /* --- @acl_check@ --- * |
162 | * |
163 | * Arguments: @acl_entry *a@ = pointer to ACL to check against |
164 | * @struct in_addr addr@ = address to check |
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165 | * @unsigned port@ = port number to check |
166 | * @int *act@ = verdict (should initially be @ACT_ALLOW@) |
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167 | * |
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168 | * Returns: Zero if undecided, nonzero if a rule matched. |
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169 | * |
170 | * Use: Checks an address against an ACL. |
171 | */ |
172 | |
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173 | int acl_check(acl_entry *a, struct in_addr addr, unsigned port, int *act) |
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174 | { |
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175 | for (; a; a = a->next) { |
176 | if (a->ops->check(a, addr, port)) { |
177 | *act = a->act & ACL_PERM; |
178 | return (1); |
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179 | } |
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180 | *act = (a->act & ACL_PERM) ^ 1; |
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181 | } |
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182 | return (0); |
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183 | } |
184 | |
185 | /* --- @acl_dump@ --- * |
186 | * |
187 | * Arguments: @acl_entry *a@ = pointer to ACL to dump |
188 | * @FILE *fp@ = pointer to stream to dump on |
189 | * |
190 | * Returns: --- |
191 | * |
192 | * Use: Dumps an access control list to an output stream. |
193 | */ |
194 | |
195 | void acl_dump(acl_entry *a, FILE *fp) |
196 | { |
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197 | for (; a; a = a->next) { |
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198 | fprintf(fp, " %s ", |
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199 | (a->act & ACL_PERM) == ACL_ALLOW ? "allow" : "deny"); |
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200 | a->ops->dump(a, fp); |
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201 | fputc('\n', fp); |
202 | } |
203 | } |
204 | |
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205 | /* --- @acl_free@ --- * |
206 | * |
207 | * Arguments: @acl_entry *a@ = pointer to a list of ACLs |
208 | * |
209 | * Returns: --- |
210 | * |
211 | * Use: Frees all of the memory used by an ACL. |
212 | */ |
213 | |
214 | void acl_free(acl_entry *a) |
215 | { |
216 | while (a) { |
217 | acl_entry *aa = a; |
218 | a = a->next; |
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219 | aa->ops->free(aa); |
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220 | } |
221 | } |
222 | |
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223 | /*----- That's all, folks -------------------------------------------------*/ |