1/* Copyright (C) 1998-2023 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
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
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18#include <assert.h>
19#include <errno.h>
20#include <pwd.h>
21#include <stdint.h>
22#include <stdio.h>
23#include <stdlib.h>
24#include <string.h>
25#include <unistd.h>
26#include <sys/mman.h>
27#include <sys/socket.h>
28#include <sys/uio.h>
29#include <sys/un.h>
30#include <not-cancel.h>
31#include <_itoa.h>
32
33#include "nscd-client.h"
34#include "nscd_proto.h"
35
36int __nss_not_use_nscd_passwd;
37
38static int nscd_getpw_r (const char *key, size_t keylen, request_type type,
39 struct passwd *resultbuf, char *buffer,
40 size_t buflen, struct passwd **result);
41
42int
43__nscd_getpwnam_r (const char *name, struct passwd *resultbuf, char *buffer,
44 size_t buflen, struct passwd **result)
45{
46 if (name == NULL)
47 return -1;
48
49 return nscd_getpw_r (name, strlen (name) + 1, GETPWBYNAME, resultbuf,
50 buffer, buflen, result);
51}
52
53int
54__nscd_getpwuid_r (uid_t uid, struct passwd *resultbuf, char *buffer,
55 size_t buflen, struct passwd **result)
56{
57 char buf[3 * sizeof (uid_t)];
58 buf[sizeof (buf) - 1] = '\0';
59 char *cp = _itoa_word (uid, buf + sizeof (buf) - 1, 10, 0);
60
61 return nscd_getpw_r (cp, buf + sizeof (buf) - cp, GETPWBYUID, resultbuf,
62 buffer, buflen, result);
63}
64
65
66libc_locked_map_ptr (static, map_handle);
67/* Note that we only free the structure if necessary. The memory
68 mapping is not removed since it is not visible to the malloc
69 handling. */
70libc_freeres_fn (pw_map_free)
71{
72 if (map_handle.mapped != NO_MAPPING)
73 {
74 void *p = map_handle.mapped;
75 map_handle.mapped = NO_MAPPING;
76 free (p);
77 }
78}
79
80
81static int
82nscd_getpw_r (const char *key, size_t keylen, request_type type,
83 struct passwd *resultbuf, char *buffer, size_t buflen,
84 struct passwd **result)
85{
86 int gc_cycle;
87 int nretries = 0;
88
89 /* If the mapping is available, try to search there instead of
90 communicating with the nscd. */
91 struct mapped_database *mapped;
92 mapped = __nscd_get_map_ref (GETFDPW, "passwd", &map_handle, &gc_cycle);
93
94 retry:;
95 const char *pw_name = NULL;
96 int retval = -1;
97 const char *recend = (const char *) ~UINTMAX_C (0);
98 pw_response_header pw_resp;
99
100 if (mapped != NO_MAPPING)
101 {
102 struct datahead *found = __nscd_cache_search (type, key, keylen, mapped,
103 sizeof pw_resp);
104 if (found != NULL)
105 {
106 pw_name = (const char *) (&found->data[0].pwdata + 1);
107 pw_resp = found->data[0].pwdata;
108 recend = (const char *) found->data + found->recsize;
109 /* Now check if we can trust pw_resp fields. If GC is
110 in progress, it can contain anything. */
111 if (mapped->head->gc_cycle != gc_cycle)
112 {
113 retval = -2;
114 goto out;
115 }
116 }
117 }
118
119 int sock = -1;
120 if (pw_name == NULL)
121 {
122 sock = __nscd_open_socket (key, keylen, type, &pw_resp,
123 sizeof (pw_resp));
124 if (sock == -1)
125 {
126 __nss_not_use_nscd_passwd = 1;
127 goto out;
128 }
129 }
130
131 /* No value found so far. */
132 *result = NULL;
133
134 if (__glibc_unlikely (pw_resp.found == -1))
135 {
136 /* The daemon does not cache this database. */
137 __nss_not_use_nscd_passwd = 1;
138 goto out_close;
139 }
140
141 if (pw_resp.found == 1)
142 {
143 /* Set the information we already have. */
144 resultbuf->pw_uid = pw_resp.pw_uid;
145 resultbuf->pw_gid = pw_resp.pw_gid;
146
147 char *p = buffer;
148 /* get pw_name */
149 resultbuf->pw_name = p;
150 p += pw_resp.pw_name_len;
151 /* get pw_passwd */
152 resultbuf->pw_passwd = p;
153 p += pw_resp.pw_passwd_len;
154 /* get pw_gecos */
155 resultbuf->pw_gecos = p;
156 p += pw_resp.pw_gecos_len;
157 /* get pw_dir */
158 resultbuf->pw_dir = p;
159 p += pw_resp.pw_dir_len;
160 /* get pw_pshell */
161 resultbuf->pw_shell = p;
162 p += pw_resp.pw_shell_len;
163
164 ssize_t total = p - buffer;
165 if (__glibc_unlikely (pw_name + total > recend))
166 goto out_close;
167 if (__glibc_unlikely (buflen < total))
168 {
169 __set_errno (ERANGE);
170 retval = ERANGE;
171 goto out_close;
172 }
173
174 retval = 0;
175 if (pw_name == NULL)
176 {
177 ssize_t nbytes = __readall (sock, buffer, total);
178
179 if (__glibc_unlikely (nbytes != total))
180 {
181 /* The `errno' to some value != ERANGE. */
182 __set_errno (ENOENT);
183 retval = ENOENT;
184 }
185 else
186 *result = resultbuf;
187 }
188 else
189 {
190 /* Copy the various strings. */
191 memcpy (resultbuf->pw_name, pw_name, total);
192
193 /* Try to detect corrupt databases. */
194 if (resultbuf->pw_name[pw_resp.pw_name_len - 1] != '\0'
195 || resultbuf->pw_passwd[pw_resp.pw_passwd_len - 1] != '\0'
196 || resultbuf->pw_gecos[pw_resp.pw_gecos_len - 1] != '\0'
197 || resultbuf->pw_dir[pw_resp.pw_dir_len - 1] != '\0'
198 || resultbuf->pw_shell[pw_resp.pw_shell_len - 1] != '\0')
199 {
200 /* We cannot use the database. */
201 retval = mapped->head->gc_cycle != gc_cycle ? -2 : -1;
202 goto out_close;
203 }
204
205 *result = resultbuf;
206 }
207 }
208 else
209 {
210 /* Set errno to 0 to indicate no error, just no found record. */
211 __set_errno (0);
212 /* Even though we have not found anything, the result is zero. */
213 retval = 0;
214 }
215
216 out_close:
217 if (sock != -1)
218 __close_nocancel_nostatus (sock);
219 out:
220 if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0)
221 {
222 /* When we come here this means there has been a GC cycle while we
223 were looking for the data. This means the data might have been
224 inconsistent. Retry if possible. */
225 if ((gc_cycle & 1) != 0 || ++nretries == 5 || retval == -1)
226 {
227 /* nscd is just running gc now. Disable using the mapping. */
228 if (atomic_fetch_add_relaxed (&mapped->counter, -1) == 1)
229 __nscd_unmap (mapped);
230 mapped = NO_MAPPING;
231 }
232
233 if (retval != -1)
234 goto retry;
235 }
236
237 return retval;
238}
239