1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
|
/*++
/* NAME
/* server_acl 3
/* SUMMARY
/* server access list
/* SYNOPSIS
/* #include <server_acl.h>
/*
/* void server_acl_pre_jail_init(mynetworks, param_name)
/* const char *mynetworks;
/* const char *param_name;
/*
/* SERVER_ACL *server_acl_parse(extern_acl, param_name)
/* const char *extern_acl;
/* const char *param_name;
/*
/* int server_acl_eval(client_addr, intern_acl, param_name)
/* const char *client_addr;
/* SERVER_ACL *intern_acl;
/* const char *param_name;
/* DESCRIPTION
/* This module implements a permanent black/whitelist that
/* is meant to be evaluated immediately after a client connects
/* to a server.
/*
/* server_acl_pre_jail_init() does before-chroot initialization
/* for the permit_mynetworks setting.
/*
/* server_acl_parse() converts an access list from raw string
/* form to binary form. It should also be called as part of
/* before-chroot initialization.
/*
/* server_acl_eval() evaluates an access list for the specified
/* client address. The result is SERVER_ACL_ACT_PERMIT (permit),
/* SERVER_ACL_ACT_REJECT (reject), SERVER_ACL_ACT_DUNNO (no
/* decision), or SERVER_ACL_ACT_ERROR (error, unknown command
/* or database access error).
/*
/* Arguments:
/* .IP mynetworks
/* Network addresses that match "permit_mynetworks".
/* .IP param_name
/* The configuration parameter name for the access list from
/* main.cf. The information is used for error reporting (nested
/* table, unknown keyword) and to select the appropriate
/* behavior from parent_domain_matches_subdomains.
/* .IP extern_acl
/* External access list representation.
/* .IP intern_acl
/* Internal access list representation.
/* .IP client_addr
/* The client IP address as printable string (without []).
/* LICENSE
/* .ad
/* .fi
/* The Secure Mailer license must be distributed with this software.
/* AUTHOR(S)
/* Wietse Venema
/* IBM T.J. Watson Research
/* P.O. Box 704
/* Yorktown Heights, NY 10598, USA
/*--*/
/* System library. */
#include <sys_defs.h>
#include <string.h>
#ifdef STRCASECMP_IN_STRINGS_H
#include <strings.h>
#endif
/* Utility library. */
#include <msg.h>
#include <mymalloc.h>
#include <stringops.h>
#include <dict.h>
/* Global library. */
#include <mail_params.h>
#include <addr_match_list.h>
#include <match_parent_style.h>
#include <mynetworks.h>
#include <server_acl.h>
/* Application-specific. */
static ADDR_MATCH_LIST *server_acl_mynetworks;
static ADDR_MATCH_LIST *server_acl_mynetworks_host;
#define STR vstring_str
/* server_acl_pre_jail_init - initialize */
void server_acl_pre_jail_init(const char *mynetworks, const char *origin)
{
if (server_acl_mynetworks) {
addr_match_list_free(server_acl_mynetworks);
if (server_acl_mynetworks_host)
addr_match_list_free(server_acl_mynetworks_host);
}
server_acl_mynetworks =
addr_match_list_init(origin, MATCH_FLAG_RETURN
| match_parent_style(origin), mynetworks);
if (warn_compat_break_mynetworks_style)
server_acl_mynetworks_host =
addr_match_list_init(origin, MATCH_FLAG_RETURN
| match_parent_style(origin), mynetworks_host());
}
/* server_acl_parse - parse access list */
SERVER_ACL *server_acl_parse(const char *extern_acl, const char *origin)
{
char *saved_acl = mystrdup(extern_acl);
SERVER_ACL *intern_acl = argv_alloc(1);
char *bp = saved_acl;
char *acl;
#define STREQ(x,y) (strcasecmp((x), (y)) == 0)
#define STRNE(x,y) (strcasecmp((x), (y)) != 0)
/*
* Nested tables are not allowed. Tables are opened before entering the
* chroot jail, while access lists are evaluated after entering the
* chroot jail.
*/
while ((acl = mystrtokq(&bp, CHARS_COMMA_SP, CHARS_BRACE)) != 0) {
if (strchr(acl, ':') != 0) {
if (strchr(origin, ':') != 0) {
msg_warn("table %s: lookup result \"%s\" is not allowed"
" -- ignoring remainder of access list",
origin, acl);
argv_add(intern_acl, SERVER_ACL_NAME_DUNNO, (char *) 0);
break;
} else {
if (dict_handle(acl) == 0)
dict_register(acl, dict_open(acl, O_RDONLY, DICT_FLAG_LOCK
| DICT_FLAG_FOLD_FIX
| DICT_FLAG_UTF8_REQUEST));
}
}
argv_add(intern_acl, acl, (char *) 0);
}
argv_terminate(intern_acl);
/*
* Cleanup.
*/
myfree(saved_acl);
return (intern_acl);
}
/* server_acl_eval - evaluate access list */
int server_acl_eval(const char *client_addr, SERVER_ACL * intern_acl,
const char *origin)
{
const char *myname = "server_acl_eval";
char **cpp;
DICT *dict;
SERVER_ACL *argv;
const char *acl;
const char *dict_val;
int ret;
for (cpp = intern_acl->argv; (acl = *cpp) != 0; cpp++) {
if (msg_verbose)
msg_info("source=%s address=%s acl=%s",
origin, client_addr, acl);
if (STREQ(acl, SERVER_ACL_NAME_REJECT)) {
return (SERVER_ACL_ACT_REJECT);
} else if (STREQ(acl, SERVER_ACL_NAME_PERMIT)) {
return (SERVER_ACL_ACT_PERMIT);
} else if (STREQ(acl, SERVER_ACL_NAME_WL_MYNETWORKS)) {
if (addr_match_list_match(server_acl_mynetworks, client_addr)) {
if (warn_compat_break_mynetworks_style
&& !addr_match_list_match(server_acl_mynetworks_host,
client_addr))
msg_info("using backwards-compatible default setting "
VAR_MYNETWORKS_STYLE "=%s to permit "
"request from client \"%s\"",
var_mynetworks_style, client_addr);
return (SERVER_ACL_ACT_PERMIT);
}
if (server_acl_mynetworks->error != 0) {
msg_warn("%s: %s: mynetworks lookup error -- ignoring the "
"remainder of this access list", origin, acl);
return (SERVER_ACL_ACT_ERROR);
}
} else if (strchr(acl, ':') != 0) {
if ((dict = dict_handle(acl)) == 0)
msg_panic("%s: unexpected dictionary: %s", myname, acl);
if ((dict_val = dict_get(dict, client_addr)) != 0) {
/* Fake up an ARGV to avoid lots of mallocs and frees. */
if (dict_val[strcspn(dict_val, ":" CHARS_COMMA_SP)] == 0) {
ARGV_FAKE_BEGIN(fake_argv, dict_val);
ret = server_acl_eval(client_addr, &fake_argv, acl);
ARGV_FAKE_END;
} else {
argv = server_acl_parse(dict_val, acl);
ret = server_acl_eval(client_addr, argv, acl);
argv_free(argv);
}
if (ret != SERVER_ACL_ACT_DUNNO)
return (ret);
} else if (dict->error != 0) {
msg_warn("%s: %s: table lookup error -- ignoring the remainder "
"of this access list", origin, acl);
return (SERVER_ACL_ACT_ERROR);
}
} else if (STREQ(acl, SERVER_ACL_NAME_DUNNO)) {
return (SERVER_ACL_ACT_DUNNO);
} else {
msg_warn("%s: unknown command: %s -- ignoring the remainder "
"of this access list", origin, acl);
return (SERVER_ACL_ACT_ERROR);
}
}
if (msg_verbose)
msg_info("source=%s address=%s - no match",
origin, client_addr);
return (SERVER_ACL_ACT_DUNNO);
}
/*
* Access lists need testing. Not only with good inputs; error cases must
* also be handled appropriately.
*/
#ifdef TEST
#include <unistd.h>
#include <stdlib.h>
#include <vstring_vstream.h>
#include <name_code.h>
#include <split_at.h>
char *var_par_dom_match = DEF_PAR_DOM_MATCH;
char *var_mynetworks = "";
char *var_server_acl = "";
#define UPDATE_VAR(s,v) do { if (*(s)) myfree(s); (s) = mystrdup(v); } while (0)
int main(void)
{
VSTRING *buf = vstring_alloc(100);
SERVER_ACL *argv;
int ret;
int have_tty = isatty(0);
char *bufp;
char *cmd;
char *value;
const NAME_CODE acl_map[] = {
SERVER_ACL_NAME_ERROR, SERVER_ACL_ACT_ERROR,
SERVER_ACL_NAME_PERMIT, SERVER_ACL_ACT_PERMIT,
SERVER_ACL_NAME_REJECT, SERVER_ACL_ACT_REJECT,
SERVER_ACL_NAME_DUNNO, SERVER_ACL_ACT_DUNNO,
0,
};
#define VAR_SERVER_ACL "server_acl"
while (vstring_get_nonl(buf, VSTREAM_IN) != VSTREAM_EOF) {
bufp = STR(buf);
if (have_tty == 0) {
vstream_printf("> %s\n", bufp);
vstream_fflush(VSTREAM_OUT);
}
if (*bufp == '#')
continue;
if ((cmd = mystrtok(&bufp, " =")) == 0 || STREQ(cmd, "?")) {
vstream_printf("usage: %s=value|%s=value|address=value\n",
VAR_MYNETWORKS, VAR_SERVER_ACL);
} else if ((value = mystrtok(&bufp, " =")) == 0) {
vstream_printf("missing value\n");
} else if (STREQ(cmd, VAR_MYNETWORKS)) {
UPDATE_VAR(var_mynetworks, value);
} else if (STREQ(cmd, VAR_SERVER_ACL)) {
UPDATE_VAR(var_server_acl, value);
} else if (STREQ(cmd, "address")) {
server_acl_pre_jail_init(var_mynetworks, VAR_MYNETWORKS);
argv = server_acl_parse(var_server_acl, VAR_SERVER_ACL);
ret = server_acl_eval(value, argv, VAR_SERVER_ACL);
argv_free(argv);
vstream_printf("%s: %s\n", value, str_name_code(acl_map, ret));
} else {
vstream_printf("unknown command: \"%s\"\n", cmd);
}
vstream_fflush(VSTREAM_OUT);
}
vstring_free(buf);
exit(0);
}
#endif
|
