1 | /* Copyright (C) 1998-2017 Free Software Foundation, Inc. |
2 | This file is part of the GNU C Library. |
3 | Contributed by Thorsten Kukuk <kukuk@uni-paderborn.de>, 1998. |
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 <pwd.h> |
22 | #include <stdint.h> |
23 | #include <stdio.h> |
24 | #include <stdlib.h> |
25 | #include <string.h> |
26 | #include <unistd.h> |
27 | #include <sys/mman.h> |
28 | #include <sys/socket.h> |
29 | #include <sys/uio.h> |
30 | #include <sys/un.h> |
31 | #include <not-cancel.h> |
32 | #include <_itoa.h> |
33 | |
34 | #include "nscd-client.h" |
35 | #include "nscd_proto.h" |
36 | |
37 | int __nss_not_use_nscd_passwd; |
38 | |
39 | static int nscd_getpw_r (const char *key, size_t keylen, request_type type, |
40 | struct passwd *resultbuf, char *buffer, |
41 | size_t buflen, struct passwd **result) |
42 | internal_function; |
43 | |
44 | int |
45 | __nscd_getpwnam_r (const char *name, struct passwd *resultbuf, char *buffer, |
46 | size_t buflen, struct passwd **result) |
47 | { |
48 | if (name == NULL) |
49 | return -1; |
50 | |
51 | return nscd_getpw_r (name, strlen (name) + 1, GETPWBYNAME, resultbuf, |
52 | buffer, buflen, result); |
53 | } |
54 | |
55 | int |
56 | __nscd_getpwuid_r (uid_t uid, struct passwd *resultbuf, char *buffer, |
57 | size_t buflen, struct passwd **result) |
58 | { |
59 | char buf[3 * sizeof (uid_t)]; |
60 | buf[sizeof (buf) - 1] = '\0'; |
61 | char *cp = _itoa_word (uid, buf + sizeof (buf) - 1, 10, 0); |
62 | |
63 | return nscd_getpw_r (cp, buf + sizeof (buf) - cp, GETPWBYUID, resultbuf, |
64 | buffer, buflen, result); |
65 | } |
66 | |
67 | |
68 | libc_locked_map_ptr (static, map_handle); |
69 | /* Note that we only free the structure if necessary. The memory |
70 | mapping is not removed since it is not visible to the malloc |
71 | handling. */ |
72 | libc_freeres_fn (pw_map_free) |
73 | { |
74 | if (map_handle.mapped != NO_MAPPING) |
75 | { |
76 | void *p = map_handle.mapped; |
77 | map_handle.mapped = NO_MAPPING; |
78 | free (p); |
79 | } |
80 | } |
81 | |
82 | |
83 | static int |
84 | internal_function |
85 | nscd_getpw_r (const char *key, size_t keylen, request_type type, |
86 | struct passwd *resultbuf, char *buffer, size_t buflen, |
87 | struct passwd **result) |
88 | { |
89 | int gc_cycle; |
90 | int nretries = 0; |
91 | |
92 | /* If the mapping is available, try to search there instead of |
93 | communicating with the nscd. */ |
94 | struct mapped_database *mapped; |
95 | mapped = __nscd_get_map_ref (GETFDPW, "passwd" , &map_handle, &gc_cycle); |
96 | |
97 | retry:; |
98 | const char *pw_name = NULL; |
99 | int retval = -1; |
100 | const char *recend = (const char *) ~UINTMAX_C (0); |
101 | pw_response_header pw_resp; |
102 | |
103 | if (mapped != NO_MAPPING) |
104 | { |
105 | struct datahead *found = __nscd_cache_search (type, key, keylen, mapped, |
106 | sizeof pw_resp); |
107 | if (found != NULL) |
108 | { |
109 | pw_name = (const char *) (&found->data[0].pwdata + 1); |
110 | pw_resp = found->data[0].pwdata; |
111 | recend = (const char *) found->data + found->recsize; |
112 | /* Now check if we can trust pw_resp fields. If GC is |
113 | in progress, it can contain anything. */ |
114 | if (mapped->head->gc_cycle != gc_cycle) |
115 | { |
116 | retval = -2; |
117 | goto out; |
118 | } |
119 | } |
120 | } |
121 | |
122 | int sock = -1; |
123 | if (pw_name == NULL) |
124 | { |
125 | sock = __nscd_open_socket (key, keylen, type, &pw_resp, |
126 | sizeof (pw_resp)); |
127 | if (sock == -1) |
128 | { |
129 | __nss_not_use_nscd_passwd = 1; |
130 | goto out; |
131 | } |
132 | } |
133 | |
134 | /* No value found so far. */ |
135 | *result = NULL; |
136 | |
137 | if (__glibc_unlikely (pw_resp.found == -1)) |
138 | { |
139 | /* The daemon does not cache this database. */ |
140 | __nss_not_use_nscd_passwd = 1; |
141 | goto out_close; |
142 | } |
143 | |
144 | if (pw_resp.found == 1) |
145 | { |
146 | /* Set the information we already have. */ |
147 | resultbuf->pw_uid = pw_resp.pw_uid; |
148 | resultbuf->pw_gid = pw_resp.pw_gid; |
149 | |
150 | char *p = buffer; |
151 | /* get pw_name */ |
152 | resultbuf->pw_name = p; |
153 | p += pw_resp.pw_name_len; |
154 | /* get pw_passwd */ |
155 | resultbuf->pw_passwd = p; |
156 | p += pw_resp.pw_passwd_len; |
157 | /* get pw_gecos */ |
158 | resultbuf->pw_gecos = p; |
159 | p += pw_resp.pw_gecos_len; |
160 | /* get pw_dir */ |
161 | resultbuf->pw_dir = p; |
162 | p += pw_resp.pw_dir_len; |
163 | /* get pw_pshell */ |
164 | resultbuf->pw_shell = p; |
165 | p += pw_resp.pw_shell_len; |
166 | |
167 | ssize_t total = p - buffer; |
168 | if (__glibc_unlikely (pw_name + total > recend)) |
169 | goto out_close; |
170 | if (__glibc_unlikely (buflen < total)) |
171 | { |
172 | __set_errno (ERANGE); |
173 | retval = ERANGE; |
174 | goto out_close; |
175 | } |
176 | |
177 | retval = 0; |
178 | if (pw_name == NULL) |
179 | { |
180 | ssize_t nbytes = __readall (sock, buffer, total); |
181 | |
182 | if (__glibc_unlikely (nbytes != total)) |
183 | { |
184 | /* The `errno' to some value != ERANGE. */ |
185 | __set_errno (ENOENT); |
186 | retval = ENOENT; |
187 | } |
188 | else |
189 | *result = resultbuf; |
190 | } |
191 | else |
192 | { |
193 | /* Copy the various strings. */ |
194 | memcpy (resultbuf->pw_name, pw_name, total); |
195 | |
196 | /* Try to detect corrupt databases. */ |
197 | if (resultbuf->pw_name[pw_resp.pw_name_len - 1] != '\0' |
198 | || resultbuf->pw_passwd[pw_resp.pw_passwd_len - 1] != '\0' |
199 | || resultbuf->pw_gecos[pw_resp.pw_gecos_len - 1] != '\0' |
200 | || resultbuf->pw_dir[pw_resp.pw_dir_len - 1] != '\0' |
201 | || resultbuf->pw_shell[pw_resp.pw_shell_len - 1] != '\0') |
202 | { |
203 | /* We cannot use the database. */ |
204 | retval = mapped->head->gc_cycle != gc_cycle ? -2 : -1; |
205 | goto out_close; |
206 | } |
207 | |
208 | *result = resultbuf; |
209 | } |
210 | } |
211 | else |
212 | { |
213 | /* Set errno to 0 to indicate no error, just no found record. */ |
214 | __set_errno (0); |
215 | /* Even though we have not found anything, the result is zero. */ |
216 | retval = 0; |
217 | } |
218 | |
219 | out_close: |
220 | if (sock != -1) |
221 | close_not_cancel_no_status (sock); |
222 | out: |
223 | if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0) |
224 | { |
225 | /* When we come here this means there has been a GC cycle while we |
226 | were looking for the data. This means the data might have been |
227 | inconsistent. Retry if possible. */ |
228 | if ((gc_cycle & 1) != 0 || ++nretries == 5 || retval == -1) |
229 | { |
230 | /* nscd is just running gc now. Disable using the mapping. */ |
231 | if (atomic_decrement_val (&mapped->counter) == 0) |
232 | __nscd_unmap (mapped); |
233 | mapped = NO_MAPPING; |
234 | } |
235 | |
236 | if (retval != -1) |
237 | goto retry; |
238 | } |
239 | |
240 | return retval; |
241 | } |
242 | |