1 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
2 /* dbus-nonce.c Nonce handling functions used by nonce-tcp (internal to D-Bus implementation)
4 * Copyright (C) 2009 Klaralvdalens Datakonsult AB, a KDAB Group company, info@kdab.net
6 * Licensed under the Academic Free License version 2.1
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation; either version 2 of the License, or
11 * (at your option) any later version.
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
25 // major sections of this file are modified code from libassuan, (C) FSF
26 #include "dbus-nonce.h"
27 #include "dbus-internals.h"
28 #include "dbus-protocol.h"
29 #include "dbus-sysdeps.h"
34 do_check_nonce (int fd, const DBusString *nonce, DBusError *error)
42 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
46 if ( !_dbus_string_init (&buffer)
47 || !_dbus_string_init (&p) ) {
48 dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
49 _dbus_string_free (&p);
50 _dbus_string_free (&buffer);
56 n = _dbus_read_socket (fd, &p, nleft);
57 if (n == -1 && _dbus_get_is_errno_eintr())
59 else if (n == -1 && _dbus_get_is_errno_eagain_or_ewouldblock())
60 _dbus_sleep_milliseconds (100);
63 dbus_set_error (error, DBUS_ERROR_IO_ERROR, "Could not read nonce from socket (fd=%d)", fd );
64 _dbus_string_free (&p);
65 _dbus_string_free (&buffer);
70 _dbus_string_free (&p);
71 _dbus_string_free (&buffer);
72 dbus_set_error (error, DBUS_ERROR_IO_ERROR, "Could not read nonce from socket (fd=%d)", fd );
77 _dbus_string_append_len(&buffer, _dbus_string_get_const_data (&p), n);
82 result = _dbus_string_equal_len (&buffer, nonce, 16);
84 dbus_set_error (error, DBUS_ERROR_ACCESS_DENIED, "Nonces do not match, access denied (fd=%d)", fd );
86 _dbus_string_free (&p);
87 _dbus_string_free (&buffer);
93 * reads the nonce from the nonce file and stores it in a string
95 * @param fname the file to read the nonce from
96 * @param nonce returns the nonce. Must be an initialized string, the nonce will be appended.
97 * @param error error object to report possible errors
98 * @return FALSE iff reading the nonce fails (error is set then)
101 _dbus_read_nonce (const DBusString *fname, DBusString *nonce, DBusError* error)
107 buffer[sizeof buffer - 1] = '\0';
109 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
111 _dbus_verbose ("reading nonce from file: %s\n", _dbus_string_get_const_data (fname));
114 fp = fopen (_dbus_string_get_const_data (fname), "rb");
117 nread = fread (buffer, 1, sizeof buffer - 1, fp);
121 dbus_set_error (error, DBUS_ERROR_FILE_NOT_FOUND, "Could not read nonce from file %s", _dbus_string_get_const_data (fname));
125 if (!_dbus_string_append_len (nonce, buffer, sizeof buffer - 1 ))
127 dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
134 _dbus_accept_with_noncefile (int listen_fd, const DBusNonceFile *noncefile)
139 _dbus_assert (noncefile != NULL);
140 if (!_dbus_string_init (&nonce))
142 //PENDING(kdab): set better errors
143 if (_dbus_read_nonce (_dbus_noncefile_get_path(noncefile), &nonce, NULL) != TRUE)
145 fd = _dbus_accept (listen_fd);
146 if (_dbus_socket_is_invalid (fd))
148 if (do_check_nonce(fd, &nonce, NULL) != TRUE) {
149 _dbus_verbose ("nonce check failed. Closing socket.\n");
150 _dbus_close_socket(fd, NULL);
158 generate_and_write_nonce (const DBusString *filename, DBusError *error)
163 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
165 if (!_dbus_string_init (&nonce))
167 dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
171 if (!_dbus_generate_random_bytes (&nonce, 16))
173 dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
174 _dbus_string_free (&nonce);
178 ret = _dbus_string_save_to_file (&nonce, filename, FALSE, error);
180 _dbus_string_free (&nonce);
186 * sends the nonce over a given socket. Blocks while doing so.
188 * @param fd the file descriptor to write the nonce data to (usually a socket)
189 * @param noncefile the noncefile location to read the nonce from
190 * @param error contains error details if FALSE is returned
191 * @return TRUE iff the nonce was successfully sent. Note that this does not
192 * indicate whether the server accepted the nonce.
195 _dbus_send_nonce (int fd, const DBusString *noncefile, DBusError *error)
197 dbus_bool_t read_result;
202 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
204 if (_dbus_string_get_length (noncefile) == 0)
207 if (!_dbus_string_init (&nonce))
209 dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
213 read_result = _dbus_read_nonce (noncefile, &nonce, error);
216 _DBUS_ASSERT_ERROR_IS_SET (error);
217 _dbus_string_free (&nonce);
220 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
222 send_result = _dbus_write_socket (fd, &nonce, 0, _dbus_string_get_length (&nonce));
224 _dbus_string_free (&nonce);
226 if (send_result == -1)
228 dbus_set_error (error,
229 _dbus_error_from_system_errno (),
230 "Failed to send nonce (fd=%d): %s",
231 fd, _dbus_strerror_from_errno ());
239 do_noncefile_create (DBusNonceFile *noncefile,
241 dbus_bool_t use_subdir)
244 DBusString randomStr;
246 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
248 _dbus_assert (noncefile);
250 if (!_dbus_string_init (&randomStr))
252 dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
256 if (!_dbus_generate_random_ascii (&randomStr, 8))
258 dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
262 if (!_dbus_string_init (&noncefile->dir)
263 || !_dbus_string_append (&noncefile->dir, _dbus_get_tmpdir()))
265 dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
270 if (!_dbus_string_append (&noncefile->dir, "/dbus_nonce-")
271 || !_dbus_string_append (&noncefile->dir, _dbus_string_get_const_data (&randomStr)) )
273 dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
276 if (!_dbus_string_init (&noncefile->path)
277 || !_dbus_string_copy (&noncefile->dir, 0, &noncefile->path, 0)
278 || !_dbus_string_append (&noncefile->path, "/nonce"))
280 dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
283 if (!_dbus_create_directory (&noncefile->dir, error))
285 _DBUS_ASSERT_ERROR_IS_SET (error);
288 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
293 if (!_dbus_string_init (&noncefile->path)
294 || !_dbus_string_copy (&noncefile->dir, 0, &noncefile->path, 0)
295 || !_dbus_string_append (&noncefile->path, "/dbus_nonce-")
296 || !_dbus_string_append (&noncefile->path, _dbus_string_get_const_data (&randomStr)))
298 dbus_set_error (error, DBUS_ERROR_NO_MEMORY, NULL);
304 if (!generate_and_write_nonce (&noncefile->path, error))
306 _DBUS_ASSERT_ERROR_IS_SET (error);
308 _dbus_delete_directory (&noncefile->dir, NULL); //we ignore possible errors deleting the dir and return the write error instead
311 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
313 _dbus_string_free (&randomStr);
318 _dbus_delete_directory (&noncefile->dir, NULL);
319 _dbus_string_free (&noncefile->dir);
320 _dbus_string_free (&noncefile->path);
321 _dbus_string_free (&randomStr);
327 * creates a nonce file in a user-readable location and writes a generated nonce to it
329 * @param noncefile returns the nonce file location
330 * @param error error details if creating the nonce file fails
331 * @return TRUE iff the nonce file was successfully created
334 _dbus_noncefile_create (DBusNonceFile *noncefile,
337 return do_noncefile_create (noncefile, error, /*use_subdir=*/FALSE);
341 * deletes the noncefile and frees the DBusNonceFile object.
343 * @param noncefile the nonce file to delete. Contents will be freed.
344 * @param error error details if the nonce file could not be deleted
348 _dbus_noncefile_delete (DBusNonceFile *noncefile,
351 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
353 _dbus_delete_file (&noncefile->path, error);
354 _dbus_string_free (&noncefile->dir);
355 _dbus_string_free (&noncefile->path);
361 * creates a nonce file in a user-readable location and writes a generated nonce to it.
362 * Initializes the noncefile object.
364 * @param noncefile returns the nonce file location
365 * @param error error details if creating the nonce file fails
366 * @return TRUE iff the nonce file was successfully created
369 _dbus_noncefile_create (DBusNonceFile *noncefile,
372 return do_noncefile_create (noncefile, error, /*use_subdir=*/TRUE);
376 * deletes the noncefile and frees the DBusNonceFile object.
378 * @param noncefile the nonce file to delete. Contents will be freed.
379 * @param error error details if the nonce file could not be deleted
383 _dbus_noncefile_delete (DBusNonceFile *noncefile,
386 _DBUS_ASSERT_ERROR_IS_CLEAR (error);
388 _dbus_delete_directory (&noncefile->dir, error);
389 _dbus_string_free (&noncefile->dir);
390 _dbus_string_free (&noncefile->path);
397 * returns the absolute file path of the nonce file
399 * @param noncefile an initialized noncefile object
400 * @return the absolute path of the nonce file
403 _dbus_noncefile_get_path (const DBusNonceFile *noncefile)
405 _dbus_assert (noncefile);
406 return &noncefile->path;
410 * reads data from a file descriptor and checks if the received data matches
411 * the data in the given noncefile.
413 * @param fd the file descriptor to read the nonce from
414 * @param noncefile the nonce file to check the received data against
415 * @param error error details on fail
416 * @return TRUE iff a nonce could be successfully read from the file descriptor
417 * and matches the nonce from the given nonce file
420 _dbus_noncefile_check_nonce (int fd,
421 const DBusNonceFile *noncefile,
424 return do_check_nonce (fd, _dbus_noncefile_get_path (noncefile), error);
428 /** @} end of nonce */