1/* Copyright (C) 1997-2016 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by H.J. Lu <hjl@gnu.ai.mit.edu>, 1997.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
18
19#include <assert.h>
20#include <errno.h>
21#include <string.h>
22#include <stdlib.h>
23#include <ctype.h>
24#include <wctype.h>
25#include <resolv.h>
26#include <netdb.h>
27#include <arpa/inet.h>
28#include "nsswitch.h"
29
30#ifdef USE_NSCD
31# define inet_aton __inet_aton
32# include <nscd/nscd_proto.h>
33#endif
34
35int
36__nss_hostname_digits_dots (const char *name, struct hostent *resbuf,
37 char **buffer, size_t *buffer_size,
38 size_t buflen, struct hostent **result,
39 enum nss_status *status, int af, int *h_errnop)
40{
41 int save;
42
43 /* We have to test for the use of IPv6 which can only be done by
44 examining `_res'. */
45 if (__res_maybe_init (&_res, 0) == -1)
46 {
47 if (h_errnop)
48 *h_errnop = NETDB_INTERNAL;
49 if (buffer_size == NULL)
50 *status = NSS_STATUS_TRYAGAIN;
51 else
52 *result = NULL;
53 return -1;
54 }
55
56 /*
57 * disallow names consisting only of digits/dots, unless
58 * they end in a dot.
59 */
60 if (isdigit (name[0]) || isxdigit (name[0]) || name[0] == ':')
61 {
62 const char *cp;
63 char *hostname;
64 typedef unsigned char host_addr_t[16];
65 host_addr_t *host_addr;
66 typedef char *host_addr_list_t[2];
67 host_addr_list_t *h_addr_ptrs;
68 char **h_alias_ptr;
69 size_t size_needed;
70 int addr_size;
71
72 switch (af)
73 {
74 case AF_INET:
75 addr_size = INADDRSZ;
76 break;
77
78 case AF_INET6:
79 addr_size = IN6ADDRSZ;
80 break;
81
82 default:
83 af = (_res.options & RES_USE_INET6) ? AF_INET6 : AF_INET;
84 addr_size = af == AF_INET6 ? IN6ADDRSZ : INADDRSZ;
85 break;
86 }
87
88 size_needed = (sizeof (*host_addr)
89 + sizeof (*h_addr_ptrs)
90 + sizeof (*h_alias_ptr) + strlen (name) + 1);
91
92 if (buffer_size == NULL)
93 {
94 if (buflen < size_needed)
95 {
96 *status = NSS_STATUS_TRYAGAIN;
97 if (h_errnop != NULL)
98 *h_errnop = NETDB_INTERNAL;
99 __set_errno (ERANGE);
100 goto done;
101 }
102 }
103 else if (buffer_size != NULL && *buffer_size < size_needed)
104 {
105 char *new_buf;
106 *buffer_size = size_needed;
107 new_buf = (char *) realloc (*buffer, *buffer_size);
108
109 if (new_buf == NULL)
110 {
111 save = errno;
112 free (*buffer);
113 *buffer = NULL;
114 *buffer_size = 0;
115 __set_errno (save);
116 if (h_errnop != NULL)
117 *h_errnop = NETDB_INTERNAL;
118 *result = NULL;
119 goto done;
120 }
121 *buffer = new_buf;
122 }
123
124 memset (*buffer, '\0', size_needed);
125
126 host_addr = (host_addr_t *) *buffer;
127 h_addr_ptrs = (host_addr_list_t *)
128 ((char *) host_addr + sizeof (*host_addr));
129 h_alias_ptr = (char **) ((char *) h_addr_ptrs + sizeof (*h_addr_ptrs));
130 hostname = (char *) h_alias_ptr + sizeof (*h_alias_ptr);
131
132 if (isdigit (name[0]))
133 {
134 for (cp = name;; ++cp)
135 {
136 if (*cp == '\0')
137 {
138 int ok;
139
140 if (*--cp == '.')
141 break;
142
143 /* All-numeric, no dot at the end. Fake up a hostent as if
144 we'd actually done a lookup. What if someone types
145 255.255.255.255? The test below will succeed
146 spuriously... ??? */
147 if (af == AF_INET)
148 ok = __inet_aton (name, (struct in_addr *) host_addr);
149 else
150 {
151 assert (af == AF_INET6);
152 ok = inet_pton (af, name, host_addr) > 0;
153 }
154 if (! ok)
155 {
156 *h_errnop = HOST_NOT_FOUND;
157 if (buffer_size == NULL)
158 *status = NSS_STATUS_NOTFOUND;
159 else
160 *result = NULL;
161 goto done;
162 }
163
164 resbuf->h_name = strcpy (hostname, name);
165 h_alias_ptr[0] = NULL;
166 resbuf->h_aliases = h_alias_ptr;
167 (*h_addr_ptrs)[0] = (char *) host_addr;
168 (*h_addr_ptrs)[1] = NULL;
169 resbuf->h_addr_list = *h_addr_ptrs;
170 if (af == AF_INET && (_res.options & RES_USE_INET6))
171 {
172 /* We need to change the IP v4 address into the
173 IP v6 address. */
174 char tmp[INADDRSZ];
175 char *p = (char *) host_addr;
176 int i;
177
178 /* Save a copy of the IP v4 address. */
179 memcpy (tmp, host_addr, INADDRSZ);
180 /* Mark this ipv6 addr as a mapped ipv4. */
181 for (i = 0; i < 10; i++)
182 *p++ = 0x00;
183 *p++ = 0xff;
184 *p++ = 0xff;
185 /* Copy the IP v4 address. */
186 memcpy (p, tmp, INADDRSZ);
187 resbuf->h_addrtype = AF_INET6;
188 resbuf->h_length = IN6ADDRSZ;
189 }
190 else
191 {
192 resbuf->h_addrtype = af;
193 resbuf->h_length = addr_size;
194 }
195 if (h_errnop != NULL)
196 *h_errnop = NETDB_SUCCESS;
197 if (buffer_size == NULL)
198 *status = NSS_STATUS_SUCCESS;
199 else
200 *result = resbuf;
201 goto done;
202 }
203
204 if (!isdigit (*cp) && *cp != '.')
205 break;
206 }
207 }
208
209 if ((isxdigit (name[0]) && strchr (name, ':') != NULL) || name[0] == ':')
210 {
211 switch (af)
212 {
213 default:
214 af = (_res.options & RES_USE_INET6) ? AF_INET6 : AF_INET;
215 if (af == AF_INET6)
216 {
217 addr_size = IN6ADDRSZ;
218 break;
219 }
220 /* FALLTHROUGH */
221
222 case AF_INET:
223 /* This is not possible. We cannot represent an IPv6 address
224 in an `struct in_addr' variable. */
225 *h_errnop = HOST_NOT_FOUND;
226 if (buffer_size == NULL)
227 *status = NSS_STATUS_NOTFOUND;
228 else
229 *result = NULL;
230 goto done;
231
232 case AF_INET6:
233 addr_size = IN6ADDRSZ;
234 break;
235 }
236
237 for (cp = name;; ++cp)
238 {
239 if (!*cp)
240 {
241 if (*--cp == '.')
242 break;
243
244 /* All-IPv6-legal, no dot at the end. Fake up a
245 hostent as if we'd actually done a lookup. */
246 if (inet_pton (AF_INET6, name, host_addr) <= 0)
247 {
248 *h_errnop = HOST_NOT_FOUND;
249 if (buffer_size == NULL)
250 *status = NSS_STATUS_NOTFOUND;
251 else
252 *result = NULL;
253 goto done;
254 }
255
256 resbuf->h_name = strcpy (hostname, name);
257 h_alias_ptr[0] = NULL;
258 resbuf->h_aliases = h_alias_ptr;
259 (*h_addr_ptrs)[0] = (char *) host_addr;
260 (*h_addr_ptrs)[1] = (char *) 0;
261 resbuf->h_addr_list = *h_addr_ptrs;
262 resbuf->h_addrtype = AF_INET6;
263 resbuf->h_length = addr_size;
264 *h_errnop = NETDB_SUCCESS;
265 if (buffer_size == NULL)
266 *status = NSS_STATUS_SUCCESS;
267 else
268 *result = resbuf;
269 goto done;
270 }
271
272 if (!isxdigit (*cp) && *cp != ':' && *cp != '.')
273 break;
274 }
275 }
276 }
277
278 return 0;
279
280done:
281 return 1;
282}
283libc_hidden_def (__nss_hostname_digits_dots)
284