dbus-marshal-validate.c revision 3ed9db546e1143bc9aa2d83a6f423fdd81227352
1/* -*- mode: C; c-file-style: "gnu" -*- */
2/* dbus-marshal-validate.c Validation routines for marshaled data
3 *
4 * Copyright (C) 2005 Red Hat, Inc.
5 *
6 * Licensed under the Academic Free License version 2.1
7 *
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.
12 *
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.
17 *
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
21 *
22 */
23
24#include "dbus-internals.h"
25#include "dbus-marshal-validate.h"
26#include "dbus-marshal-recursive.h"
27#include "dbus-marshal-basic.h"
28#include "dbus-string.h"
29
30/**
31 * @addtogroup DBusMarshal
32 *
33 * @{
34 */
35
36/**
37 * Verifies that the range of type_str from type_pos to type_end is a
38 * valid signature.  If this function returns #TRUE, it will be safe
39 * to iterate over the signature with a types-only #DBusTypeReader.
40 * The range passed in should NOT include the terminating
41 * nul/DBUS_TYPE_INVALID.
42 *
43 * @param type_str the string
44 * @param type_pos where the typecodes start
45 * @param len length of typecodes
46 * @returns #DBUS_VALID if valid, reason why invalid otherwise
47 */
48DBusValidity
49_dbus_validate_signature_with_reason (const DBusString *type_str,
50                                      int               type_pos,
51                                      int               len)
52{
53  const unsigned char *p;
54  const unsigned char *end;
55  int last;
56  int struct_depth;
57  int array_depth;
58
59  _dbus_assert (type_str != NULL);
60  _dbus_assert (type_pos < _DBUS_INT32_MAX - len);
61  _dbus_assert (len >= 0);
62  _dbus_assert (type_pos >= 0);
63
64  if (len > DBUS_MAXIMUM_SIGNATURE_LENGTH)
65    return DBUS_INVALID_SIGNATURE_TOO_LONG;
66
67  p = _dbus_string_get_const_data_len (type_str, type_pos, 0);
68  end = _dbus_string_get_const_data_len (type_str, type_pos + len, 0);
69  struct_depth = 0;
70  array_depth = 0;
71  last = DBUS_TYPE_INVALID;
72
73  while (p != end)
74    {
75      switch (*p)
76        {
77        case DBUS_TYPE_BYTE:
78        case DBUS_TYPE_BOOLEAN:
79        case DBUS_TYPE_INT16:
80        case DBUS_TYPE_UINT16:
81        case DBUS_TYPE_INT32:
82        case DBUS_TYPE_UINT32:
83        case DBUS_TYPE_INT64:
84        case DBUS_TYPE_UINT64:
85        case DBUS_TYPE_DOUBLE:
86        case DBUS_TYPE_STRING:
87        case DBUS_TYPE_OBJECT_PATH:
88        case DBUS_TYPE_SIGNATURE:
89        case DBUS_TYPE_VARIANT:
90          break;
91
92        case DBUS_TYPE_ARRAY:
93          array_depth += 1;
94          if (array_depth > DBUS_MAXIMUM_TYPE_RECURSION_DEPTH)
95            return DBUS_INVALID_EXCEEDED_MAXIMUM_ARRAY_RECURSION;
96          break;
97
98        case DBUS_STRUCT_BEGIN_CHAR:
99          struct_depth += 1;
100
101          if (struct_depth > DBUS_MAXIMUM_TYPE_RECURSION_DEPTH)
102            return DBUS_INVALID_EXCEEDED_MAXIMUM_STRUCT_RECURSION;
103          break;
104
105        case DBUS_STRUCT_END_CHAR:
106          if (struct_depth == 0)
107            return DBUS_INVALID_STRUCT_ENDED_BUT_NOT_STARTED;
108
109          if (last == DBUS_STRUCT_BEGIN_CHAR)
110            return DBUS_INVALID_STRUCT_HAS_NO_FIELDS;
111
112          struct_depth -= 1;
113          break;
114
115        case DBUS_TYPE_STRUCT: /* doesn't appear in signatures */
116        default:
117          return DBUS_INVALID_UNKNOWN_TYPECODE;
118        }
119
120      if (*p != DBUS_TYPE_ARRAY)
121        array_depth = 0;
122
123      last = *p;
124      ++p;
125    }
126
127  if (array_depth > 0)
128    return DBUS_INVALID_MISSING_ARRAY_ELEMENT_TYPE;
129
130  if (struct_depth > 0)
131    return DBUS_INVALID_STRUCT_STARTED_BUT_NOT_ENDED;
132
133  return DBUS_VALID;
134}
135
136static DBusValidity
137validate_body_helper (DBusTypeReader       *reader,
138                      int                   byte_order,
139                      dbus_bool_t           walk_reader_to_end,
140                      const unsigned char  *p,
141                      const unsigned char  *end,
142                      const unsigned char **new_p)
143{
144  int current_type;
145
146  while ((current_type = _dbus_type_reader_get_current_type (reader)) != DBUS_TYPE_INVALID)
147    {
148      const unsigned char *a;
149      int alignment;
150
151      _dbus_verbose ("   validating value of type %s type reader %p type_pos %d p %p end %p %d remain\n",
152                     _dbus_type_to_string (current_type), reader, reader->type_pos, p, end,
153                     (int) (end - p));
154
155      /* Guarantee that p has one byte to look at */
156      if (p == end)
157        return DBUS_INVALID_NOT_ENOUGH_DATA;
158
159      switch (current_type)
160        {
161        case DBUS_TYPE_BYTE:
162          ++p;
163          break;
164
165        case DBUS_TYPE_BOOLEAN:
166        case DBUS_TYPE_INT16:
167        case DBUS_TYPE_UINT16:
168        case DBUS_TYPE_INT32:
169        case DBUS_TYPE_UINT32:
170        case DBUS_TYPE_INT64:
171        case DBUS_TYPE_UINT64:
172        case DBUS_TYPE_DOUBLE:
173          alignment = _dbus_type_get_alignment (current_type);
174          a = _DBUS_ALIGN_ADDRESS (p, alignment);
175          if (a >= end)
176            return DBUS_INVALID_NOT_ENOUGH_DATA;
177          while (p != a)
178            {
179              if (*p != '\0')
180                return DBUS_INVALID_ALIGNMENT_PADDING_NOT_NUL;
181              ++p;
182            }
183
184          if (current_type == DBUS_TYPE_BOOLEAN)
185            {
186              dbus_uint32_t v = _dbus_unpack_uint32 (byte_order,
187                                                     p);
188              if (!(v == 0 || v == 1))
189                return DBUS_INVALID_BOOLEAN_NOT_ZERO_OR_ONE;
190            }
191
192          p += alignment;
193          break;
194
195        case DBUS_TYPE_ARRAY:
196        case DBUS_TYPE_STRING:
197        case DBUS_TYPE_OBJECT_PATH:
198          {
199            dbus_uint32_t claimed_len;
200
201            a = _DBUS_ALIGN_ADDRESS (p, 4);
202            if (a + 4 > end)
203              return DBUS_INVALID_NOT_ENOUGH_DATA;
204            while (p != a)
205              {
206                if (*p != '\0')
207                  return DBUS_INVALID_ALIGNMENT_PADDING_NOT_NUL;
208                ++p;
209              }
210
211            claimed_len = _dbus_unpack_uint32 (byte_order, p);
212            p += 4;
213
214            /* p may now be == end */
215            _dbus_assert (p <= end);
216
217            if (current_type == DBUS_TYPE_ARRAY)
218              {
219                int array_elem_type = _dbus_type_reader_get_element_type (reader);
220                alignment = _dbus_type_get_alignment (array_elem_type);
221                p = _DBUS_ALIGN_ADDRESS (p, alignment);
222              }
223
224            if (claimed_len > (unsigned long) (end - p))
225              return DBUS_INVALID_STRING_LENGTH_OUT_OF_BOUNDS;
226
227            if (current_type == DBUS_TYPE_OBJECT_PATH)
228              {
229                DBusString str;
230                _dbus_string_init_const_len (&str, p, claimed_len);
231                if (!_dbus_validate_path (&str, 0,
232                                          _dbus_string_get_length (&str)))
233                  return DBUS_INVALID_BAD_PATH;
234
235                p += claimed_len;
236              }
237            else if (current_type == DBUS_TYPE_STRING)
238              {
239                DBusString str;
240                _dbus_string_init_const_len (&str, p, claimed_len);
241                if (!_dbus_string_validate_utf8 (&str, 0,
242                                                 _dbus_string_get_length (&str)))
243                  return DBUS_INVALID_BAD_UTF8_IN_STRING;
244
245                p += claimed_len;
246              }
247            else if (current_type == DBUS_TYPE_ARRAY && claimed_len > 0)
248              {
249                DBusTypeReader sub;
250                DBusValidity validity;
251                const unsigned char *array_end;
252
253                /* Remember that the reader is types only, so we can't
254                 * use it to iterate over elements. It stays the same
255                 * for all elements.
256                 */
257                _dbus_type_reader_recurse (reader, &sub);
258
259                array_end = p + claimed_len;
260
261                while (p < array_end)
262                  {
263                    /* FIXME we are calling a function per array element! very bad
264                     * need if (dbus_type_is_fixed(elem_type)) here to just skip
265                     * big blocks of ints/bytes/etc.
266                     */
267
268                    validity = validate_body_helper (&sub, byte_order, FALSE, p, end, &p);
269                    if (validity != DBUS_VALID)
270                      return validity;
271                  }
272
273                if (p != array_end)
274                  return DBUS_INVALID_ARRAY_LENGTH_INCORRECT;
275              }
276
277            /* check nul termination */
278            if (current_type != DBUS_TYPE_ARRAY)
279              {
280                if (p == end)
281                  return DBUS_INVALID_NOT_ENOUGH_DATA;
282
283                if (*p != '\0')
284                  return DBUS_INVALID_STRING_MISSING_NUL;
285                ++p;
286              }
287          }
288          break;
289
290        case DBUS_TYPE_SIGNATURE:
291          {
292            dbus_uint32_t claimed_len;
293            DBusString str;
294
295            claimed_len = *p;
296            ++p;
297
298            /* 1 is for nul termination */
299            if (claimed_len + 1 > (unsigned long) (end - p))
300              return DBUS_INVALID_SIGNATURE_LENGTH_OUT_OF_BOUNDS;
301
302            _dbus_string_init_const_len (&str, p, claimed_len);
303            if (!_dbus_validate_signature (&str, 0,
304                                           _dbus_string_get_length (&str)))
305              return DBUS_INVALID_BAD_SIGNATURE;
306
307            p += claimed_len;
308
309            _dbus_assert (p < end);
310            if (*p != DBUS_TYPE_INVALID)
311              return DBUS_INVALID_SIGNATURE_MISSING_NUL;
312
313            ++p;
314
315            _dbus_verbose ("p = %p end = %p claimed_len %u\n", p, end, claimed_len);
316          }
317          break;
318
319        case DBUS_TYPE_VARIANT:
320          {
321            /* 1 byte sig len, sig typecodes, align to
322             * contained-type-boundary, values.
323             */
324
325            /* In addition to normal signature validation, we need to be sure
326             * the signature contains only a single (possibly container) type.
327             */
328            dbus_uint32_t claimed_len;
329            DBusString sig;
330            DBusTypeReader sub;
331            DBusValidity validity;
332            int contained_alignment;
333
334            claimed_len = *p;
335            ++p;
336
337            /* + 1 for nul */
338            if (claimed_len + 1 > (unsigned long) (end - p))
339              return DBUS_INVALID_VARIANT_SIGNATURE_LENGTH_OUT_OF_BOUNDS;
340
341            _dbus_string_init_const_len (&sig, p, claimed_len);
342            if (!_dbus_validate_signature (&sig, 0,
343                                           _dbus_string_get_length (&sig)))
344              return DBUS_INVALID_VARIANT_SIGNATURE_BAD;
345
346            p += claimed_len;
347
348            if (*p != DBUS_TYPE_INVALID)
349              return DBUS_INVALID_VARIANT_SIGNATURE_MISSING_NUL;
350            ++p;
351
352            contained_alignment = _dbus_type_get_alignment (_dbus_first_type_in_signature (&sig, 0));
353
354            a = _DBUS_ALIGN_ADDRESS (p, contained_alignment);
355            if (a > end)
356              return DBUS_INVALID_NOT_ENOUGH_DATA;
357            while (p != a)
358              {
359                if (*p != '\0')
360                  return DBUS_INVALID_ALIGNMENT_PADDING_NOT_NUL;
361                ++p;
362              }
363
364            _dbus_type_reader_init_types_only (&sub, &sig, 0);
365
366            if (_dbus_type_reader_get_current_type (&sub) == DBUS_TYPE_INVALID)
367              return DBUS_INVALID_VARIANT_SIGNATURE_EMPTY;
368
369            validity = validate_body_helper (&sub, byte_order, FALSE, p, end, &p);
370            if (validity != DBUS_VALID)
371              return validity;
372
373            if (_dbus_type_reader_next (&sub))
374              return DBUS_INVALID_VARIANT_SIGNATURE_SPECIFIES_MULTIPLE_VALUES;
375
376            _dbus_assert (_dbus_type_reader_get_current_type (&sub) == DBUS_TYPE_INVALID);
377          }
378          break;
379
380        case DBUS_TYPE_STRUCT:
381          {
382            DBusTypeReader sub;
383            DBusValidity validity;
384
385            a = _DBUS_ALIGN_ADDRESS (p, 8);
386            if (a > end)
387              return DBUS_INVALID_NOT_ENOUGH_DATA;
388            while (p != a)
389              {
390                if (*p != '\0')
391                  return DBUS_INVALID_ALIGNMENT_PADDING_NOT_NUL;
392                ++p;
393              }
394
395            _dbus_type_reader_recurse (reader, &sub);
396
397            validity = validate_body_helper (&sub, byte_order, TRUE, p, end, &p);
398            if (validity != DBUS_VALID)
399              return validity;
400          }
401          break;
402
403        default:
404          _dbus_assert_not_reached ("invalid typecode in supposedly-validated signature");
405          break;
406        }
407
408      _dbus_verbose ("   validated value of type %s type reader %p type_pos %d p %p end %p %d remain\n",
409                     _dbus_type_to_string (current_type), reader, reader->type_pos, p, end,
410                     (int) (end - p));
411
412      if (p > end)
413        {
414          _dbus_verbose ("not enough data!!! p = %p end = %p end-p = %d\n",
415                         p, end, (int) (end - p));
416          return DBUS_INVALID_NOT_ENOUGH_DATA;
417        }
418
419      if (walk_reader_to_end)
420        _dbus_type_reader_next (reader);
421      else
422        break;
423    }
424
425  if (new_p)
426    *new_p = p;
427
428  return DBUS_VALID;
429}
430
431/**
432 * Verifies that the range of value_str from value_pos to value_end is
433 * a legitimate value of type expected_signature.  If this function
434 * returns #TRUE, it will be safe to iterate over the values with
435 * #DBusTypeReader. The signature is assumed to be already valid.
436 *
437 * If bytes_remaining is not #NULL, then leftover bytes will be stored
438 * there and #DBUS_VALID returned. If it is #NULL, then
439 * #DBUS_INVALID_TOO_MUCH_DATA will be returned if bytes are left
440 * over.
441 *
442 * @param expected_signature the expected types in the value_str
443 * @param expected_signature_start where in expected_signature is the signature
444 * @param byte_order the byte order
445 * @param bytes_remaining place to store leftover bytes
446 * @param value_str the string containing the body
447 * @param value_pos where the values start
448 * @param len length of values after value_pos
449 * @returns #DBUS_VALID if valid, reason why invalid otherwise
450 */
451DBusValidity
452_dbus_validate_body_with_reason (const DBusString *expected_signature,
453                                 int               expected_signature_start,
454                                 int               byte_order,
455                                 int              *bytes_remaining,
456                                 const DBusString *value_str,
457                                 int               value_pos,
458                                 int               len)
459{
460  DBusTypeReader reader;
461  const unsigned char *p;
462  const unsigned char *end;
463  DBusValidity validity;
464
465  _dbus_assert (len >= 0);
466  _dbus_assert (value_pos >= 0);
467  _dbus_assert (value_pos <= _dbus_string_get_length (value_str) - len);
468
469  _dbus_verbose ("validating body from pos %d len %d sig '%s'\n",
470                 value_pos, len, _dbus_string_get_const_data_len (expected_signature,
471                                                                  expected_signature_start,
472                                                                  0));
473
474  _dbus_type_reader_init_types_only (&reader,
475                                     expected_signature, expected_signature_start);
476
477  p = _dbus_string_get_const_data_len (value_str, value_pos, len);
478  end = p + len;
479
480  validity = validate_body_helper (&reader, byte_order, TRUE, p, end, &p);
481  if (validity != DBUS_VALID)
482    return validity;
483
484  if (bytes_remaining)
485    {
486      *bytes_remaining = end - p;
487      return DBUS_VALID;
488    }
489  else if (p < end)
490    return DBUS_INVALID_TOO_MUCH_DATA;
491  else
492    {
493      _dbus_assert (p == end);
494      return DBUS_VALID;
495    }
496}
497
498/**
499 * Determine wether the given charater is valid as the first charater
500 * in a name.
501 */
502#define VALID_INITIAL_NAME_CHARACTER(c)         \
503  ( ((c) >= 'A' && (c) <= 'Z') ||               \
504    ((c) >= 'a' && (c) <= 'z') ||               \
505    ((c) == '_') )
506
507/**
508 * Determine wether the given charater is valid as a second or later
509 * character in a name
510 */
511#define VALID_NAME_CHARACTER(c)                 \
512  ( ((c) >= '0' && (c) <= '9') ||               \
513    ((c) >= 'A' && (c) <= 'Z') ||               \
514    ((c) >= 'a' && (c) <= 'z') ||               \
515    ((c) == '_') )
516
517/**
518 * Checks that the given range of the string is a valid object path
519 * name in the D-BUS protocol. Part of the validation ensures that
520 * the object path contains only ASCII.
521 *
522 * @todo this is inconsistent with most of DBusString in that
523 * it allows a start,len range that extends past the string end.
524 *
525 * @todo change spec to disallow more things, such as spaces in the
526 * path name
527 *
528 * @param str the string
529 * @param start first byte index to check
530 * @param len number of bytes to check
531 * @returns #TRUE if the byte range exists and is a valid name
532 */
533dbus_bool_t
534_dbus_validate_path (const DBusString  *str,
535                     int                start,
536                     int                len)
537{
538  const unsigned char *s;
539  const unsigned char *end;
540  const unsigned char *last_slash;
541
542  _dbus_assert (start >= 0);
543  _dbus_assert (len >= 0);
544  _dbus_assert (start <= _dbus_string_get_length (str));
545
546  if (len > _dbus_string_get_length (str) - start)
547    return FALSE;
548
549  if (len == 0)
550    return FALSE;
551
552  s = _dbus_string_get_const_data (str) + start;
553  end = s + len;
554
555  if (*s != '/')
556    return FALSE;
557  last_slash = s;
558  ++s;
559
560  while (s != end)
561    {
562      if (*s == '/')
563        {
564          if ((s - last_slash) < 2)
565            return FALSE; /* no empty path components allowed */
566
567          last_slash = s;
568        }
569      else
570        {
571          if (_DBUS_UNLIKELY (!VALID_NAME_CHARACTER (*s)))
572            return FALSE;
573        }
574
575      ++s;
576    }
577
578  if ((end - last_slash) < 2 &&
579      len > 1)
580    return FALSE; /* trailing slash not allowed unless the string is "/" */
581
582  return TRUE;
583}
584
585/**
586 * Checks that the given range of the string is a valid interface name
587 * in the D-BUS protocol. This includes a length restriction and an
588 * ASCII subset, see the specification.
589 *
590 * @todo this is inconsistent with most of DBusString in that
591 * it allows a start,len range that extends past the string end.
592 *
593 * @param str the string
594 * @param start first byte index to check
595 * @param len number of bytes to check
596 * @returns #TRUE if the byte range exists and is a valid name
597 */
598dbus_bool_t
599_dbus_validate_interface (const DBusString  *str,
600                          int                start,
601                          int                len)
602{
603  const unsigned char *s;
604  const unsigned char *end;
605  const unsigned char *iface;
606  const unsigned char *last_dot;
607
608  _dbus_assert (start >= 0);
609  _dbus_assert (len >= 0);
610  _dbus_assert (start <= _dbus_string_get_length (str));
611
612  if (len > _dbus_string_get_length (str) - start)
613    return FALSE;
614
615  if (len > DBUS_MAXIMUM_NAME_LENGTH)
616    return FALSE;
617
618  if (len == 0)
619    return FALSE;
620
621  last_dot = NULL;
622  iface = _dbus_string_get_const_data (str) + start;
623  end = iface + len;
624  s = iface;
625
626  /* check special cases of first char so it doesn't have to be done
627   * in the loop. Note we know len > 0
628   */
629  if (_DBUS_UNLIKELY (*s == '.')) /* disallow starting with a . */
630    return FALSE;
631  else if (_DBUS_UNLIKELY (!VALID_INITIAL_NAME_CHARACTER (*s)))
632    return FALSE;
633  else
634    ++s;
635
636  while (s != end)
637    {
638      if (*s == '.')
639        {
640          if (_DBUS_UNLIKELY ((s + 1) == end))
641            return FALSE;
642          else if (_DBUS_UNLIKELY (!VALID_INITIAL_NAME_CHARACTER (*(s + 1))))
643            return FALSE;
644          last_dot = s;
645          ++s; /* we just validated the next char, so skip two */
646        }
647      else if (_DBUS_UNLIKELY (!VALID_NAME_CHARACTER (*s)))
648        {
649          return FALSE;
650        }
651
652      ++s;
653    }
654
655  if (_DBUS_UNLIKELY (last_dot == NULL))
656    return FALSE;
657
658  return TRUE;
659}
660
661/**
662 * Checks that the given range of the string is a valid member name
663 * in the D-BUS protocol. This includes a length restriction, etc.,
664 * see the specification.
665 *
666 * @todo this is inconsistent with most of DBusString in that
667 * it allows a start,len range that extends past the string end.
668 *
669 * @param str the string
670 * @param start first byte index to check
671 * @param len number of bytes to check
672 * @returns #TRUE if the byte range exists and is a valid name
673 */
674dbus_bool_t
675_dbus_validate_member (const DBusString  *str,
676                       int                start,
677                       int                len)
678{
679  const unsigned char *s;
680  const unsigned char *end;
681  const unsigned char *member;
682
683  _dbus_assert (start >= 0);
684  _dbus_assert (len >= 0);
685  _dbus_assert (start <= _dbus_string_get_length (str));
686
687  if (len > _dbus_string_get_length (str) - start)
688    return FALSE;
689
690  if (len > DBUS_MAXIMUM_NAME_LENGTH)
691    return FALSE;
692
693  if (len == 0)
694    return FALSE;
695
696  member = _dbus_string_get_const_data (str) + start;
697  end = member + len;
698  s = member;
699
700  /* check special cases of first char so it doesn't have to be done
701   * in the loop. Note we know len > 0
702   */
703
704  if (_DBUS_UNLIKELY (!VALID_INITIAL_NAME_CHARACTER (*s)))
705    return FALSE;
706  else
707    ++s;
708
709  while (s != end)
710    {
711      if (_DBUS_UNLIKELY (!VALID_NAME_CHARACTER (*s)))
712        {
713          return FALSE;
714        }
715
716      ++s;
717    }
718
719  return TRUE;
720}
721
722/**
723 * Checks that the given range of the string is a valid error name
724 * in the D-BUS protocol. This includes a length restriction, etc.,
725 * see the specification.
726 *
727 * @todo this is inconsistent with most of DBusString in that
728 * it allows a start,len range that extends past the string end.
729 *
730 * @param str the string
731 * @param start first byte index to check
732 * @param len number of bytes to check
733 * @returns #TRUE if the byte range exists and is a valid name
734 */
735dbus_bool_t
736_dbus_validate_error_name (const DBusString  *str,
737                           int                start,
738                           int                len)
739{
740  /* Same restrictions as interface name at the moment */
741  return _dbus_validate_interface (str, start, len);
742}
743
744/* This assumes the first char exists and is ':' */
745static dbus_bool_t
746_dbus_validate_unique_name (const DBusString  *str,
747                            int                start,
748                            int                len)
749{
750  const unsigned char *s;
751  const unsigned char *end;
752  const unsigned char *name;
753
754  _dbus_assert (start >= 0);
755  _dbus_assert (len >= 0);
756  _dbus_assert (start <= _dbus_string_get_length (str));
757
758  if (len > _dbus_string_get_length (str) - start)
759    return FALSE;
760
761  if (len > DBUS_MAXIMUM_NAME_LENGTH)
762    return FALSE;
763
764  _dbus_assert (len > 0);
765
766  name = _dbus_string_get_const_data (str) + start;
767  end = name + len;
768  _dbus_assert (*name == ':');
769  s = name + 1;
770
771  while (s != end)
772    {
773      if (*s == '.')
774        {
775          if (_DBUS_UNLIKELY ((s + 1) == end))
776            return FALSE;
777          if (_DBUS_UNLIKELY (!VALID_NAME_CHARACTER (*(s + 1))))
778            return FALSE;
779          ++s; /* we just validated the next char, so skip two */
780        }
781      else if (_DBUS_UNLIKELY (!VALID_NAME_CHARACTER (*s)))
782        {
783          return FALSE;
784        }
785
786      ++s;
787    }
788
789  return TRUE;
790}
791
792/**
793 * Checks that the given range of the string is a valid bus name in
794 * the D-BUS protocol. This includes a length restriction, etc., see
795 * the specification.
796 *
797 * @todo this is inconsistent with most of DBusString in that
798 * it allows a start,len range that extends past the string end.
799 *
800 * @param str the string
801 * @param start first byte index to check
802 * @param len number of bytes to check
803 * @returns #TRUE if the byte range exists and is a valid name
804 */
805dbus_bool_t
806_dbus_validate_bus_name (const DBusString  *str,
807                         int                start,
808                         int                len)
809{
810  if (_DBUS_UNLIKELY (len == 0))
811    return FALSE;
812  if (_dbus_string_get_byte (str, start) == ':')
813    return _dbus_validate_unique_name (str, start, len);
814  else
815    return _dbus_validate_interface (str, start, len);
816}
817
818/**
819 * Checks that the given range of the string is a valid message type
820 * signature in the D-BUS protocol.
821 *
822 * @todo this is inconsistent with most of DBusString in that
823 * it allows a start,len range that extends past the string end.
824 *
825 * @param str the string
826 * @param start first byte index to check
827 * @param len number of bytes to check
828 * @returns #TRUE if the byte range exists and is a valid signature
829 */
830dbus_bool_t
831_dbus_validate_signature (const DBusString  *str,
832                          int                start,
833                          int                len)
834{
835  _dbus_assert (start >= 0);
836  _dbus_assert (start <= _dbus_string_get_length (str));
837  _dbus_assert (len >= 0);
838
839  if (len > _dbus_string_get_length (str) - start)
840    return FALSE;
841
842  return _dbus_validate_signature_with_reason (str, start, len) == DBUS_VALID;
843}
844
845/** define _dbus_check_is_valid_path() */
846DEFINE_DBUS_NAME_CHECK(path);
847/** define _dbus_check_is_valid_interface() */
848DEFINE_DBUS_NAME_CHECK(interface);
849/** define _dbus_check_is_valid_member() */
850DEFINE_DBUS_NAME_CHECK(member);
851/** define _dbus_check_is_valid_error_name() */
852DEFINE_DBUS_NAME_CHECK(error_name);
853/** define _dbus_check_is_valid_bus_name() */
854DEFINE_DBUS_NAME_CHECK(bus_name);
855/** define _dbus_check_is_valid_signature() */
856DEFINE_DBUS_NAME_CHECK(signature);
857
858/** @} */
859
860/* tests in dbus-marshal-validate-util.c */
861