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2b778ceb | 1 | /* Copyright (C) 2007-2021 Free Software Foundation, Inc. |
b21fa963 | 2 | This file is part of the GNU C Library. |
b21fa963 UD |
3 | |
4 | The GNU C Library is free software; you can redistribute it and/or | |
5 | modify it under the terms of the GNU Lesser General Public | |
6 | License as published by the Free Software Foundation; either | |
7 | version 2.1 of the License, or (at your option) any later version. | |
8 | ||
9 | The GNU C Library is distributed in the hope that it will be useful, | |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
12 | Lesser General Public License for more details. | |
13 | ||
14 | You should have received a copy of the GNU Lesser General Public | |
59ba27a6 | 15 | License along with the GNU C Library; if not, see |
5a82c748 | 16 | <https://www.gnu.org/licenses/>. */ |
b21fa963 | 17 | |
f2962a71 | 18 | #include <assert.h> |
b21fa963 UD |
19 | #include <errno.h> |
20 | #include <string.h> | |
21 | #include <not-cancel.h> | |
eb96ffb0 | 22 | #include <_itoa.h> |
e054f494 | 23 | #include <stdint.h> |
b21fa963 UD |
24 | |
25 | #include "nscd-client.h" | |
26 | #include "nscd_proto.h" | |
27 | ||
28 | ||
29 | int __nss_not_use_nscd_services; | |
30 | ||
31 | ||
32 | static int nscd_getserv_r (const char *crit, size_t critlen, const char *proto, | |
33 | request_type type, struct servent *resultbuf, | |
34 | char *buf, size_t buflen, struct servent **result); | |
35 | ||
36 | ||
37 | int | |
38 | __nscd_getservbyname_r (const char *name, const char *proto, | |
39 | struct servent *result_buf, char *buf, size_t buflen, | |
40 | struct servent **result) | |
41 | { | |
42 | return nscd_getserv_r (name, strlen (name), proto, GETSERVBYNAME, result_buf, | |
43 | buf, buflen, result); | |
44 | } | |
45 | ||
46 | ||
47 | int | |
48 | __nscd_getservbyport_r (int port, const char *proto, | |
49 | struct servent *result_buf, char *buf, size_t buflen, | |
50 | struct servent **result) | |
51 | { | |
52 | char portstr[3 * sizeof (int) + 2]; | |
53 | portstr[sizeof (portstr) - 1] = '\0'; | |
54 | char *cp = _itoa_word (port, portstr + sizeof (portstr) - 1, 10, 0); | |
55 | ||
8ec3f656 | 56 | return nscd_getserv_r (cp, portstr + sizeof (portstr) - 1 - cp, proto, |
b21fa963 UD |
57 | GETSERVBYPORT, result_buf, buf, buflen, result); |
58 | } | |
59 | ||
60 | ||
61 | libc_locked_map_ptr (, __serv_map_handle) attribute_hidden; | |
62 | /* Note that we only free the structure if necessary. The memory | |
63 | mapping is not removed since it is not visible to the malloc | |
64 | handling. */ | |
65 | libc_freeres_fn (serv_map_free) | |
66 | { | |
67 | if (__serv_map_handle.mapped != NO_MAPPING) | |
68 | { | |
69 | void *p = __serv_map_handle.mapped; | |
70 | __serv_map_handle.mapped = NO_MAPPING; | |
71 | free (p); | |
72 | } | |
73 | } | |
74 | ||
75 | ||
76 | static int | |
77 | nscd_getserv_r (const char *crit, size_t critlen, const char *proto, | |
78 | request_type type, struct servent *resultbuf, | |
79 | char *buf, size_t buflen, struct servent **result) | |
80 | { | |
81 | int gc_cycle; | |
82 | int nretries = 0; | |
f2962a71 | 83 | size_t alloca_used = 0; |
b21fa963 UD |
84 | |
85 | /* If the mapping is available, try to search there instead of | |
86 | communicating with the nscd. */ | |
87 | struct mapped_database *mapped; | |
88 | mapped = __nscd_get_map_ref (GETFDSERV, "services", &__serv_map_handle, | |
89 | &gc_cycle); | |
90 | size_t protolen = proto == NULL ? 0 : strlen (proto); | |
91 | size_t keylen = critlen + 1 + protolen + 1; | |
f2962a71 UD |
92 | int alloca_key = __libc_use_alloca (keylen); |
93 | char *key; | |
94 | if (alloca_key) | |
95 | key = alloca_account (keylen, alloca_used); | |
96 | else | |
97 | { | |
98 | key = malloc (keylen); | |
99 | if (key == NULL) | |
100 | return -1; | |
101 | } | |
b21fa963 UD |
102 | memcpy (__mempcpy (__mempcpy (key, crit, critlen), |
103 | "/", 1), proto ?: "", protolen + 1); | |
104 | ||
105 | retry:; | |
b21fa963 UD |
106 | const char *s_name = NULL; |
107 | const char *s_proto = NULL; | |
f2962a71 | 108 | int alloca_aliases_len = 0; |
b21fa963 UD |
109 | const uint32_t *aliases_len = NULL; |
110 | const char *aliases_list = NULL; | |
111 | int retval = -1; | |
112 | const char *recend = (const char *) ~UINTMAX_C (0); | |
113 | int sock = -1; | |
1a77d37f JJ |
114 | serv_response_header serv_resp; |
115 | ||
b21fa963 UD |
116 | if (mapped != NO_MAPPING) |
117 | { | |
cfe1fc10 JJ |
118 | struct datahead *found = __nscd_cache_search (type, key, keylen, mapped, |
119 | sizeof serv_resp); | |
b21fa963 UD |
120 | |
121 | if (found != NULL) | |
122 | { | |
1a77d37f JJ |
123 | s_name = (char *) (&found->data[0].servdata + 1); |
124 | serv_resp = found->data[0].servdata; | |
125 | s_proto = s_name + serv_resp.s_name_len; | |
c8fc0c91 | 126 | alloca_aliases_len = 1; |
1a77d37f | 127 | aliases_len = (uint32_t *) (s_proto + serv_resp.s_proto_len); |
b21fa963 | 128 | aliases_list = ((char *) aliases_len |
1a77d37f JJ |
129 | + serv_resp.s_aliases_cnt * sizeof (uint32_t)); |
130 | recend = (const char *) found->data + found->recsize; | |
131 | /* Now check if we can trust serv_resp fields. If GC is | |
132 | in progress, it can contain anything. */ | |
133 | if (mapped->head->gc_cycle != gc_cycle) | |
134 | { | |
135 | retval = -2; | |
136 | goto out; | |
137 | } | |
3687a5a7 JJ |
138 | if (__builtin_expect ((const char *) aliases_len |
139 | + serv_resp.s_aliases_cnt * sizeof (uint32_t) | |
140 | > recend, 0)) | |
141 | goto out; | |
b21fa963 | 142 | |
27822ce6 | 143 | #if !_STRING_ARCH_unaligned |
b21fa963 UD |
144 | /* The aliases_len array in the mapped database might very |
145 | well be unaligned. We will access it word-wise so on | |
146 | platforms which do not tolerate unaligned accesses we | |
147 | need to make an aligned copy. */ | |
148 | if (((uintptr_t) aliases_len & (__alignof__ (*aliases_len) - 1)) | |
149 | != 0) | |
150 | { | |
f2962a71 UD |
151 | uint32_t *tmp; |
152 | alloca_aliases_len | |
153 | = __libc_use_alloca (alloca_used | |
154 | + (serv_resp.s_aliases_cnt | |
155 | * sizeof (uint32_t))); | |
156 | if (alloca_aliases_len) | |
c8fc0c91 UD |
157 | tmp = alloca_account (serv_resp.s_aliases_cnt |
158 | * sizeof (uint32_t), | |
159 | alloca_used); | |
f2962a71 UD |
160 | else |
161 | { | |
162 | tmp = malloc (serv_resp.s_aliases_cnt * sizeof (uint32_t)); | |
163 | if (tmp == NULL) | |
164 | { | |
165 | retval = ENOMEM; | |
166 | goto out; | |
167 | } | |
168 | } | |
b21fa963 | 169 | aliases_len = memcpy (tmp, aliases_len, |
1a77d37f | 170 | serv_resp.s_aliases_cnt |
b21fa963 UD |
171 | * sizeof (uint32_t)); |
172 | } | |
173 | #endif | |
b21fa963 UD |
174 | } |
175 | } | |
176 | ||
1a77d37f | 177 | if (s_name == NULL) |
b21fa963 | 178 | { |
1a77d37f JJ |
179 | sock = __nscd_open_socket (key, keylen, type, &serv_resp, |
180 | sizeof (serv_resp)); | |
b21fa963 UD |
181 | if (sock == -1) |
182 | { | |
183 | __nss_not_use_nscd_services = 1; | |
184 | goto out; | |
185 | } | |
b21fa963 UD |
186 | } |
187 | ||
188 | /* No value found so far. */ | |
189 | *result = NULL; | |
190 | ||
a1ffb40e | 191 | if (__glibc_unlikely (serv_resp.found == -1)) |
b21fa963 UD |
192 | { |
193 | /* The daemon does not cache this database. */ | |
194 | __nss_not_use_nscd_services = 1; | |
195 | goto out_close; | |
196 | } | |
197 | ||
1a77d37f | 198 | if (serv_resp.found == 1) |
b21fa963 UD |
199 | { |
200 | char *cp = buf; | |
201 | uintptr_t align1; | |
202 | uintptr_t align2; | |
203 | size_t total_len; | |
204 | ssize_t cnt; | |
205 | int n; | |
206 | ||
207 | /* A first check whether the buffer is sufficiently large is possible. */ | |
208 | /* Now allocate the buffer the array for the group members. We must | |
209 | align the pointer and the base of the h_addr_list pointers. */ | |
210 | align1 = ((__alignof__ (char *) - (cp - ((char *) 0))) | |
211 | & (__alignof__ (char *) - 1)); | |
1a77d37f JJ |
212 | align2 = ((__alignof__ (char *) - ((cp + align1 + serv_resp.s_name_len |
213 | + serv_resp.s_proto_len) | |
b21fa963 UD |
214 | - ((char *) 0))) |
215 | & (__alignof__ (char *) - 1)); | |
1a77d37f | 216 | if (buflen < (align1 + serv_resp.s_name_len + serv_resp.s_proto_len |
b21fa963 | 217 | + align2 |
1a77d37f | 218 | + (serv_resp.s_aliases_cnt + 1) * sizeof (char *))) |
b21fa963 UD |
219 | { |
220 | no_room: | |
221 | __set_errno (ERANGE); | |
222 | retval = ERANGE; | |
223 | goto out_close; | |
224 | } | |
225 | cp += align1; | |
226 | ||
227 | /* Prepare the result as far as we can. */ | |
228 | resultbuf->s_aliases = (char **) cp; | |
1a77d37f | 229 | cp += (serv_resp.s_aliases_cnt + 1) * sizeof (char *); |
b21fa963 UD |
230 | |
231 | resultbuf->s_name = cp; | |
1a77d37f | 232 | cp += serv_resp.s_name_len; |
b21fa963 | 233 | resultbuf->s_proto = cp; |
1a77d37f JJ |
234 | cp += serv_resp.s_proto_len + align2; |
235 | resultbuf->s_port = serv_resp.s_port; | |
b21fa963 UD |
236 | |
237 | if (s_name == NULL) | |
238 | { | |
239 | struct iovec vec[2]; | |
240 | ||
241 | vec[0].iov_base = resultbuf->s_name; | |
1a77d37f | 242 | vec[0].iov_len = serv_resp.s_name_len + serv_resp.s_proto_len; |
b21fa963 UD |
243 | total_len = vec[0].iov_len; |
244 | n = 1; | |
245 | ||
1a77d37f | 246 | if (serv_resp.s_aliases_cnt > 0) |
b21fa963 | 247 | { |
f2962a71 UD |
248 | assert (alloca_aliases_len == 0); |
249 | alloca_aliases_len | |
250 | = __libc_use_alloca (alloca_used | |
251 | + (serv_resp.s_aliases_cnt | |
252 | * sizeof (uint32_t))); | |
253 | if (alloca_aliases_len) | |
c8fc0c91 UD |
254 | aliases_len = alloca_account (serv_resp.s_aliases_cnt |
255 | * sizeof (uint32_t), | |
256 | alloca_used); | |
f2962a71 UD |
257 | else |
258 | { | |
259 | aliases_len = malloc (serv_resp.s_aliases_cnt | |
260 | * sizeof (uint32_t)); | |
261 | if (aliases_len == NULL) | |
262 | { | |
263 | retval = ENOMEM; | |
264 | goto out_close; | |
265 | } | |
266 | } | |
b21fa963 | 267 | vec[n].iov_base = (void *) aliases_len; |
1a77d37f | 268 | vec[n].iov_len = serv_resp.s_aliases_cnt * sizeof (uint32_t); |
b21fa963 | 269 | |
1a77d37f | 270 | total_len += serv_resp.s_aliases_cnt * sizeof (uint32_t); |
b21fa963 UD |
271 | ++n; |
272 | } | |
273 | ||
274 | if ((size_t) __readvall (sock, vec, n) != total_len) | |
275 | goto out_close; | |
276 | } | |
277 | else | |
278 | memcpy (resultbuf->s_name, s_name, | |
1a77d37f | 279 | serv_resp.s_name_len + serv_resp.s_proto_len); |
b21fa963 UD |
280 | |
281 | /* Now we also can read the aliases. */ | |
282 | total_len = 0; | |
1a77d37f | 283 | for (cnt = 0; cnt < serv_resp.s_aliases_cnt; ++cnt) |
b21fa963 UD |
284 | { |
285 | resultbuf->s_aliases[cnt] = cp; | |
286 | cp += aliases_len[cnt]; | |
287 | total_len += aliases_len[cnt]; | |
288 | } | |
289 | resultbuf->s_aliases[cnt] = NULL; | |
290 | ||
291 | if (__builtin_expect ((const char *) aliases_list + total_len > recend, | |
292 | 0)) | |
1a77d37f JJ |
293 | { |
294 | /* aliases_len array might contain garbage during nscd GC cycle, | |
295 | retry rather than fail in that case. */ | |
296 | if (aliases_list != NULL && mapped->head->gc_cycle != gc_cycle) | |
297 | retval = -2; | |
298 | goto out_close; | |
299 | } | |
300 | ||
b21fa963 | 301 | /* See whether this would exceed the buffer capacity. */ |
a1ffb40e | 302 | if (__glibc_unlikely (cp > buf + buflen)) |
1a77d37f JJ |
303 | { |
304 | /* aliases_len array might contain garbage during nscd GC cycle, | |
305 | retry rather than fail in that case. */ | |
306 | if (aliases_list != NULL && mapped->head->gc_cycle != gc_cycle) | |
307 | { | |
308 | retval = -2; | |
309 | goto out_close; | |
310 | } | |
311 | goto no_room; | |
312 | } | |
b21fa963 UD |
313 | |
314 | /* And finally read the aliases. */ | |
315 | if (aliases_list == NULL) | |
316 | { | |
317 | if (total_len == 0 | |
318 | || ((size_t) __readall (sock, resultbuf->s_aliases[0], total_len) | |
319 | == total_len)) | |
320 | { | |
321 | retval = 0; | |
322 | *result = resultbuf; | |
323 | } | |
324 | } | |
325 | else | |
326 | { | |
327 | memcpy (resultbuf->s_aliases[0], aliases_list, total_len); | |
328 | ||
329 | /* Try to detect corrupt databases. */ | |
1a77d37f JJ |
330 | if (resultbuf->s_name[serv_resp.s_name_len - 1] != '\0' |
331 | || resultbuf->s_proto[serv_resp.s_proto_len - 1] != '\0' | |
332 | || ({for (cnt = 0; cnt < serv_resp.s_aliases_cnt; ++cnt) | |
b21fa963 UD |
333 | if (resultbuf->s_aliases[cnt][aliases_len[cnt] - 1] |
334 | != '\0') | |
335 | break; | |
1a77d37f JJ |
336 | cnt < serv_resp.s_aliases_cnt; })) |
337 | { | |
338 | /* We cannot use the database. */ | |
339 | if (mapped->head->gc_cycle != gc_cycle) | |
340 | retval = -2; | |
341 | goto out_close; | |
342 | } | |
b21fa963 UD |
343 | |
344 | retval = 0; | |
345 | *result = resultbuf; | |
346 | } | |
347 | } | |
348 | else | |
349 | { | |
cfca0aa3 UD |
350 | /* Set errno to 0 to indicate no error, just no found record. */ |
351 | __set_errno (0); | |
b21fa963 UD |
352 | /* Even though we have not found anything, the result is zero. */ |
353 | retval = 0; | |
354 | } | |
355 | ||
356 | out_close: | |
357 | if (sock != -1) | |
c181840c | 358 | __close_nocancel_nostatus (sock); |
b21fa963 | 359 | out: |
1a77d37f | 360 | if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0) |
b21fa963 UD |
361 | { |
362 | /* When we come here this means there has been a GC cycle while we | |
363 | were looking for the data. This means the data might have been | |
364 | inconsistent. Retry if possible. */ | |
1a77d37f | 365 | if ((gc_cycle & 1) != 0 || ++nretries == 5 || retval == -1) |
b21fa963 UD |
366 | { |
367 | /* nscd is just running gc now. Disable using the mapping. */ | |
1a77d37f JJ |
368 | if (atomic_decrement_val (&mapped->counter) == 0) |
369 | __nscd_unmap (mapped); | |
b21fa963 UD |
370 | mapped = NO_MAPPING; |
371 | } | |
372 | ||
1a77d37f | 373 | if (retval != -1) |
c8fc0c91 UD |
374 | { |
375 | if (!alloca_aliases_len) | |
f15f1e45 | 376 | free ((void *) aliases_len); |
c8fc0c91 UD |
377 | goto retry; |
378 | } | |
b21fa963 UD |
379 | } |
380 | ||
f2962a71 UD |
381 | if (!alloca_aliases_len) |
382 | free ((void *) aliases_len); | |
383 | if (!alloca_key) | |
384 | free (key); | |
385 | ||
b21fa963 UD |
386 | return retval; |
387 | } |