leafnode  1.12.0
About: Leafnode is a store & forward NNTP proxy for small (dialup) sites.
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validatefqdn.c
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1/*
2 * validatefqdn.c -- part of leafnode.
3 *
4 * Copyright (C) 2002 - 2010 Matthias Andree <matthias.andree@gmx.de>.
5 * All rights reserved.
6 *
7
8 Redistribution and use in source and binary forms, with or without
9 modification, are permitted provided that the following conditions are
10 met:
11
12 * Redistributions of source code must retain the above copyright notice,
13 this list of conditions and the following disclaimer.
14 * Redistributions in binary form must reproduce the above copyright
15 notice, this list of conditions and the following disclaimer in the
16 documentation and/or other materials provided with the distribution.
17 * Neither the name of Matthias Andree nor the names of its
18 contributors may be used to endorse or promote products derived from
19 this software without specific prior written permission.
20
21 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
22 IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
23 THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
24 PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE
25 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
26 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
27 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
28 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
29 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
30 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
31 POSSIBILITY OF SUCH DAMAGE.
32*/
33
34/* This function checks that the hostname contains at least a dot, does
35 * not start with localhost and does not start with 127.0.0. -- if it
36 * does, syslog, print to stderr and die.
37 */
38
39#include "leafnode.h"
40
41#include <stdio.h>
42#include <stdlib.h>
43#include <string.h>
44#ifdef HAVE_STRINGS_H
45#include <strings.h>
46#endif
47#include <signal.h>
48
49#include <syslog.h>
50
51#include "validatefqdn.h"
52
53static int strcasecmpsuffix(const char *string, const char *suffix)
54{
55 size_t lin = strlen(string);
56 size_t lsu = strlen(suffix);
57
58 if (lsu > lin) return -1;
59
60 return strcasecmp(string + lin - lsu, suffix);
61}
62
63/** Check the supplied FQDN for validity.
64 * \return 0 if invalid, 1 if valid
65 */
66int is_validfqdn(const char *f) {
67 /* do not let us fool by trailing dots */
68 char *fqdn = strdup(f);
69 if (!fqdn) return 0;
70 while (fqdn[strlen(fqdn)-1] == '.')
71 fqdn[strlen(fqdn)-1] = '\0';
72
73 if (/* reject unqualified names */
74 !(strchr(fqdn, '.'))
75 /* Red Hat list the FQDN on the same line as localhost, thus,
76 * the qualification returns two "localhost*" aliases */
77 || 0 == strncasecmp(fqdn, "localhost", 9)
78 /* protect against broken hosts or DNS */
79 || 0 == strncmp(fqdn, "127.", 4)
80 /* SuSE default hostname on some installs is linux.local */
81 || 0 == strcasecmp(fqdn, "linux.local")
82 /* kill RFC 2606 second- and top-level domains */
83 || 0 == strcasecmpsuffix(fqdn, "example.org")
84 || 0 == strcasecmpsuffix(fqdn, "example.com")
85 || 0 == strcasecmpsuffix(fqdn, "example.net")
86 || 0 == strcasecmpsuffix(fqdn, ".example")
87 || 0 == strcasecmpsuffix(fqdn, ".invalid")
88 || 0 == strcasecmpsuffix(fqdn, ".local")
89 || 0 == strcasecmpsuffix(fqdn, ".localdomain")
90 || 0 == strcasecmpsuffix(fqdn, ".localhost")
91 || 0 == strcasecmpsuffix(fqdn, ".test")
92 || 0 == strcasecmpsuffix(fqdn, ".site")
93 )
94 {
95 free(fqdn);
96 return 0;
97 }
98 free(fqdn);
99 return 1;
100}
101
102void
103validatefqdn(int logtostdout)
104{
105 /* kill bogus fqdn */
106 if (!is_validfqdn(fqdn)) {
107 const char *const fmt =
108 "\nLeafnode must have a fully-qualified and globally unique domain name,\n"
109 "not just \"%s\".\nEdit your /etc/hosts file to add "
110 "a unique, fully qualified domain name.\n"
111 "\"localhost.localdomain\" or thereabouts "
112 "will not work;\nit's qualified, but not unique.\n"
113 "Please see the README-FQDN file for details.\n\n";
114
115 if (logtostdout) {
116 printf("503 Leafnode must have a unique fully-qualified domain name. "
117 "Have its administrator fix the configuration. "
118 "More detail is in the logs.\r\n");
119 fflush(stdout);
120 }
121 syslog(LOG_CRIT, fmt, fqdn); /* RATS: ignore */
122 fprintf(stderr, fmt, fqdn); /* RATS: ignore */
123 raise(SIGKILL);
124 }
125}
126
127#ifdef TEST
128int verbose = 0;
129int debug = 0;
130char fqdn[FQDNLEN + 1] = "";
131
132int main(int argc, char **argv) {
133 int i = 1;
134 if (argc == 1) {
135 while(fgets(fqdn, sizeof(fqdn), stdin)) {
136 fqdn[strcspn(fqdn, " \t\r\n")] = '\0';
137 printf("validatefqdn(\"%s\") = %d\n", fqdn, is_validfqdn(fqdn));
138 }
139 } else {
140
141 while (i < argc && argv[i]) {
142 printf("validatefqdn(\"%s\") = %d\n", argv[i], is_validfqdn(argv[i]));
143 i++;
144 }
145 }
146 return 0;
147}
148#endif
int main(void)
Definition: amiroot.c:12
int verbose
Definition: applyfilter.c:31
int debug
Definition: applyfilter.c:30
char * strdup(const char *)
Definition: strdup.c:5
char fqdn[255+1]
Definition: miscutil.c:58
#define FQDNLEN
Definition: leafnode.h:288
int is_validfqdn(const char *f)
Definition: validatefqdn.c:66
void validatefqdn(int logtostdout)
Definition: validatefqdn.c:103
static int strcasecmpsuffix(const char *string, const char *suffix)
Definition: validatefqdn.c:53