aboutsummaryrefslogtreecommitdiff
path: root/nscd/nscd_getpw_r.c
blob: 17d9753f8a2a7156179cc1f13471c262930dc2c3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
/* Copyright (C) 1998-2023 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#include <assert.h>
#include <errno.h>
#include <pwd.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/socket.h>
#include <sys/uio.h>
#include <sys/un.h>
#include <not-cancel.h>
#include <_itoa.h>

#include "nscd-client.h"
#include "nscd_proto.h"

int __nss_not_use_nscd_passwd;

static int nscd_getpw_r (const char *key, size_t keylen, request_type type,
			 struct passwd *resultbuf, char *buffer,
			 size_t buflen, struct passwd **result);

int
__nscd_getpwnam_r (const char *name, struct passwd *resultbuf, char *buffer,
		   size_t buflen, struct passwd **result)
{
  if (name == NULL)
    return -1;

  return nscd_getpw_r (name, strlen (name) + 1, GETPWBYNAME, resultbuf,
		       buffer, buflen, result);
}

int
__nscd_getpwuid_r (uid_t uid, struct passwd *resultbuf, char *buffer,
		   size_t buflen, struct passwd **result)
{
  char buf[3 * sizeof (uid_t)];
  buf[sizeof (buf) - 1] = '\0';
  char *cp = _itoa_word (uid, buf + sizeof (buf) - 1, 10, 0);

  return nscd_getpw_r (cp, buf + sizeof (buf) - cp, GETPWBYUID, resultbuf,
		       buffer, buflen, result);
}


libc_locked_map_ptr (static, map_handle);
/* Note that we only free the structure if necessary.  The memory
   mapping is not removed since it is not visible to the malloc
   handling.  */
void
__nscd_pw_map_freemem (void)
{
  if (map_handle.mapped != NO_MAPPING)
    {
      void *p = map_handle.mapped;
      map_handle.mapped = NO_MAPPING;
      free (p);
    }
}


static int
nscd_getpw_r (const char *key, size_t keylen, request_type type,
	      struct passwd *resultbuf, char *buffer, size_t buflen,
	      struct passwd **result)
{
  int gc_cycle;
  int nretries = 0;

  /* If the mapping is available, try to search there instead of
     communicating with the nscd.  */
  struct mapped_database *mapped;
  mapped = __nscd_get_map_ref (GETFDPW, "passwd", &map_handle, &gc_cycle);

 retry:;
  const char *pw_name = NULL;
  int retval = -1;
  const char *recend = (const char *) ~UINTMAX_C (0);
  pw_response_header pw_resp;

  if (mapped != NO_MAPPING)
    {
      struct datahead *found = __nscd_cache_search (type, key, keylen, mapped,
						    sizeof pw_resp);
      if (found != NULL)
	{
	  pw_name = (const char *) (&found->data[0].pwdata + 1);
	  pw_resp = found->data[0].pwdata;
	  recend = (const char *) found->data + found->recsize;
	  /* Now check if we can trust pw_resp fields.  If GC is
	     in progress, it can contain anything.  */
	  if (mapped->head->gc_cycle != gc_cycle)
	    {
	      retval = -2;
	      goto out;
	    }
	}
    }

  int sock = -1;
  if (pw_name == NULL)
    {
      sock = __nscd_open_socket (key, keylen, type, &pw_resp,
				 sizeof (pw_resp));
      if (sock == -1)
	{
	  __nss_not_use_nscd_passwd = 1;
	  goto out;
	}
    }

  /* No value found so far.  */
  *result = NULL;

  if (__glibc_unlikely (pw_resp.found == -1))
    {
      /* The daemon does not cache this database.  */
      __nss_not_use_nscd_passwd = 1;
      goto out_close;
    }

  if (pw_resp.found == 1)
    {
      /* Set the information we already have.  */
      resultbuf->pw_uid = pw_resp.pw_uid;
      resultbuf->pw_gid = pw_resp.pw_gid;

      char *p = buffer;
      /* get pw_name */
      resultbuf->pw_name = p;
      p += pw_resp.pw_name_len;
      /* get pw_passwd */
      resultbuf->pw_passwd = p;
      p += pw_resp.pw_passwd_len;
      /* get pw_gecos */
      resultbuf->pw_gecos = p;
      p += pw_resp.pw_gecos_len;
      /* get pw_dir */
      resultbuf->pw_dir = p;
      p += pw_resp.pw_dir_len;
      /* get pw_pshell */
      resultbuf->pw_shell = p;
      p += pw_resp.pw_shell_len;

      ssize_t total = p - buffer;
      if (__glibc_unlikely (pw_name + total > recend))
	goto out_close;
      if (__glibc_unlikely (buflen < total))
	{
	  __set_errno (ERANGE);
	  retval = ERANGE;
	  goto out_close;
	}

      retval = 0;
      if (pw_name == NULL)
	{
	  ssize_t nbytes = __readall (sock, buffer, total);

	  if (__glibc_unlikely (nbytes != total))
	    {
	      /* The `errno' to some value != ERANGE.  */
	      __set_errno (ENOENT);
	      retval = ENOENT;
	    }
	  else
	    *result = resultbuf;
	}
      else
	{
	  /* Copy the various strings.  */
	  memcpy (resultbuf->pw_name, pw_name, total);

	  /* Try to detect corrupt databases.  */
	  if (resultbuf->pw_name[pw_resp.pw_name_len - 1] != '\0'
	      || resultbuf->pw_passwd[pw_resp.pw_passwd_len - 1] != '\0'
	      || resultbuf->pw_gecos[pw_resp.pw_gecos_len - 1] != '\0'
	      || resultbuf->pw_dir[pw_resp.pw_dir_len - 1] != '\0'
	      || resultbuf->pw_shell[pw_resp.pw_shell_len - 1] != '\0')
	    {
	      /* We cannot use the database.  */
	      retval = mapped->head->gc_cycle != gc_cycle ? -2 : -1;
	      goto out_close;
	    }

	  *result = resultbuf;
	}
    }
  else
    {
      /* Set errno to 0 to indicate no error, just no found record.  */
      __set_errno (0);
      /* Even though we have not found anything, the result is zero.  */
      retval = 0;
    }

 out_close:
  if (sock != -1)
    __close_nocancel_nostatus (sock);
 out:
  if (__nscd_drop_map_ref (mapped, &gc_cycle) != 0)
    {
      /* When we come here this means there has been a GC cycle while we
	 were looking for the data.  This means the data might have been
	 inconsistent.  Retry if possible.  */
      if ((gc_cycle & 1) != 0 || ++nretries == 5 || retval == -1)
	{
	  /* nscd is just running gc now.  Disable using the mapping.  */
	  if (atomic_fetch_add_relaxed (&mapped->counter, -1) == 1)
	    __nscd_unmap (mapped);
	  mapped = NO_MAPPING;
	}

      if (retval != -1)
	goto retry;
    }

  return retval;
}