1 /* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
2 /* dbus-marshal-header.c Managing marshaling/demarshaling of message headers
4 * Copyright (C) 2005 Red Hat, Inc.
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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25 #include "dbus/dbus-shared.h"
26 #include "dbus-marshal-header.h"
27 #include "dbus-marshal-recursive.h"
28 #include "dbus-marshal-byteswap.h"
31 * @addtogroup DBusMarshal
37 /* Not thread locked, but strictly const/read-only so should be OK
39 /** Static #DBusString containing the signature of a message header */
40 _DBUS_STRING_DEFINE_STATIC(_dbus_header_signature_str, DBUS_HEADER_SIGNATURE);
41 /** Static #DBusString containing the local interface */
42 _DBUS_STRING_DEFINE_STATIC(_dbus_local_interface_str, DBUS_INTERFACE_LOCAL);
43 /** Static #DBusString containing the local path */
44 _DBUS_STRING_DEFINE_STATIC(_dbus_local_path_str, DBUS_PATH_LOCAL);
46 /** Offset from start of _dbus_header_signature_str to the signature of the fields array */
47 #define FIELDS_ARRAY_SIGNATURE_OFFSET 6
48 /** Offset from start of _dbus_header_signature_str to the signature of an element of the fields array */
49 #define FIELDS_ARRAY_ELEMENT_SIGNATURE_OFFSET 7
52 /** Offset to byte order from start of header */
53 #define BYTE_ORDER_OFFSET 0
54 /** Offset to type from start of header */
56 /** Offset to flags from start of header */
57 #define FLAGS_OFFSET 2
58 /** Offset to version from start of header */
59 #define VERSION_OFFSET 3
60 /** Offset to body length from start of header */
61 #define BODY_LENGTH_OFFSET 4
62 /** Offset to client serial from start of header */
63 #define SERIAL_OFFSET 8
64 /** Offset to fields array length from start of header */
65 #define FIELDS_ARRAY_LENGTH_OFFSET 12
66 /** Offset to first field in header */
67 #define FIRST_FIELD_OFFSET 16
71 unsigned char code; /**< the field code */
72 unsigned char type; /**< the value type */
75 static const HeaderFieldType
76 _dbus_header_field_types[DBUS_HEADER_FIELD_LAST+1] = {
77 { DBUS_HEADER_FIELD_INVALID, DBUS_TYPE_INVALID },
78 { DBUS_HEADER_FIELD_PATH, DBUS_TYPE_OBJECT_PATH },
79 { DBUS_HEADER_FIELD_INTERFACE, DBUS_TYPE_STRING },
80 { DBUS_HEADER_FIELD_MEMBER, DBUS_TYPE_STRING },
81 { DBUS_HEADER_FIELD_ERROR_NAME, DBUS_TYPE_STRING },
82 { DBUS_HEADER_FIELD_REPLY_SERIAL, DBUS_TYPE_UINT32 },
83 { DBUS_HEADER_FIELD_DESTINATION, DBUS_TYPE_STRING },
84 { DBUS_HEADER_FIELD_SENDER, DBUS_TYPE_STRING },
85 { DBUS_HEADER_FIELD_SIGNATURE, DBUS_TYPE_SIGNATURE },
86 { DBUS_HEADER_FIELD_UNIX_FDS, DBUS_TYPE_UINT32 }
89 /** Macro to look up the correct type for a field */
90 #define EXPECTED_TYPE_OF_FIELD(field) (_dbus_header_field_types[field].type)
92 /** The most padding we could ever need for a header */
93 #define MAX_POSSIBLE_HEADER_PADDING 7
95 reserve_header_padding (DBusHeader *header)
97 _dbus_assert (header->padding <= MAX_POSSIBLE_HEADER_PADDING);
99 if (!_dbus_string_lengthen (&header->data,
100 MAX_POSSIBLE_HEADER_PADDING - header->padding))
102 header->padding = MAX_POSSIBLE_HEADER_PADDING;
107 correct_header_padding (DBusHeader *header)
111 _dbus_assert (header->padding == 7);
113 _dbus_string_shorten (&header->data, header->padding);
114 unpadded_len = _dbus_string_get_length (&header->data);
116 if (!_dbus_string_align_length (&header->data, 8))
117 _dbus_assert_not_reached ("couldn't pad header though enough padding was preallocated");
119 header->padding = _dbus_string_get_length (&header->data) - unpadded_len;
122 /** Compute the end of the header, ignoring padding */
123 #define HEADER_END_BEFORE_PADDING(header) \
124 (_dbus_string_get_length (&(header)->data) - (header)->padding)
127 * Invalidates all fields in the cache. This may be used when the
128 * cache is totally uninitialized (contains junk) so should not
129 * look at what's in there now.
131 * @param header the header
134 _dbus_header_cache_invalidate_all (DBusHeader *header)
139 while (i <= DBUS_HEADER_FIELD_LAST)
141 header->fields[i].value_pos = _DBUS_HEADER_FIELD_VALUE_UNKNOWN;
149 * @param header the header
150 * @param field_code the field
151 * @param variant_reader the reader for the variant in the field
154 _dbus_header_cache_one (DBusHeader *header,
156 DBusTypeReader *variant_reader)
158 header->fields[field_code].value_pos =
159 _dbus_type_reader_get_value_pos (variant_reader);
162 _dbus_verbose ("cached value_pos %d for field %d\n",
163 header->fields[field_code].value_pos, field_code)
168 * Returns the header's byte order.
170 * @param header the header
171 * @returns the byte order
174 _dbus_header_get_byte_order (const DBusHeader *header)
176 _dbus_assert (_dbus_string_get_length (&header->data) > BYTE_ORDER_OFFSET);
178 return (char) _dbus_string_get_byte (&header->data, BYTE_ORDER_OFFSET);
182 * Revalidates the fields cache
184 * @param header the header
187 _dbus_header_cache_revalidate (DBusHeader *header)
189 DBusTypeReader array;
190 DBusTypeReader reader;
194 while (i <= DBUS_HEADER_FIELD_LAST)
196 header->fields[i].value_pos = _DBUS_HEADER_FIELD_VALUE_NONEXISTENT;
200 _dbus_type_reader_init (&reader,
201 _dbus_header_get_byte_order (header),
202 &_dbus_header_signature_str,
203 FIELDS_ARRAY_SIGNATURE_OFFSET,
205 FIELDS_ARRAY_LENGTH_OFFSET);
207 _dbus_type_reader_recurse (&reader, &array);
209 while (_dbus_type_reader_get_current_type (&array) != DBUS_TYPE_INVALID)
212 DBusTypeReader variant;
213 unsigned char field_code;
215 _dbus_type_reader_recurse (&array, &sub);
217 _dbus_assert (_dbus_type_reader_get_current_type (&sub) == DBUS_TYPE_BYTE);
218 _dbus_type_reader_read_basic (&sub, &field_code);
220 /* Unknown fields should be ignored */
221 if (field_code > DBUS_HEADER_FIELD_LAST)
224 _dbus_type_reader_next (&sub);
226 _dbus_assert (_dbus_type_reader_get_current_type (&sub) == DBUS_TYPE_VARIANT);
227 _dbus_type_reader_recurse (&sub, &variant);
229 _dbus_header_cache_one (header, field_code, &variant);
232 _dbus_type_reader_next (&array);
237 * Checks for a field, updating the cache if required.
239 * @param header the header
240 * @param field the field to check
241 * @returns #FALSE if the field doesn't exist
244 _dbus_header_cache_check (DBusHeader *header,
247 _dbus_assert (field <= DBUS_HEADER_FIELD_LAST);
249 if (header->fields[field].value_pos == _DBUS_HEADER_FIELD_VALUE_UNKNOWN)
250 _dbus_header_cache_revalidate (header);
252 if (header->fields[field].value_pos == _DBUS_HEADER_FIELD_VALUE_NONEXISTENT)
259 * Checks whether a field is known not to exist. It may exist
260 * even if it's not known to exist.
262 * @param header the header
263 * @param field the field to check
264 * @returns #FALSE if the field definitely doesn't exist
267 _dbus_header_cache_known_nonexistent (DBusHeader *header,
270 _dbus_assert (field <= DBUS_HEADER_FIELD_LAST);
272 return (header->fields[field].value_pos == _DBUS_HEADER_FIELD_VALUE_NONEXISTENT);
276 * Writes a struct of { byte, variant } with the given basic type.
278 * @param writer the writer (should be ready to write a struct)
279 * @param field the header field
280 * @param type the type of the value
281 * @param value the value as for _dbus_marshal_set_basic()
282 * @returns #FALSE if no memory
285 write_basic_field (DBusTypeWriter *writer,
291 DBusTypeWriter variant;
294 unsigned char field_byte;
295 DBusString contained_type;
298 start = writer->value_pos;
299 padding = _dbus_string_get_length (writer->value_str) - start;
301 if (!_dbus_type_writer_recurse (writer, DBUS_TYPE_STRUCT,
306 if (!_dbus_type_writer_write_basic (&sub, DBUS_TYPE_BYTE,
312 _dbus_string_init_const_len (&contained_type, buf, 1);
314 if (!_dbus_type_writer_recurse (&sub, DBUS_TYPE_VARIANT,
315 &contained_type, 0, &variant))
318 if (!_dbus_type_writer_write_basic (&variant, type, value))
321 if (!_dbus_type_writer_unrecurse (&sub, &variant))
324 if (!_dbus_type_writer_unrecurse (writer, &sub))
330 _dbus_string_delete (writer->value_str,
332 _dbus_string_get_length (writer->value_str) - start - padding);
337 * Sets a struct of { byte, variant } with the given basic type.
339 * @param reader the reader (should be iterating over the array pointing at the field to set)
340 * @param field the header field
341 * @param type the type of the value
342 * @param value the value as for _dbus_marshal_set_basic()
343 * @param realign_root where to realign from
344 * @returns #FALSE if no memory
347 set_basic_field (DBusTypeReader *reader,
351 const DBusTypeReader *realign_root)
354 DBusTypeReader variant;
356 _dbus_type_reader_recurse (reader, &sub);
358 _dbus_assert (_dbus_type_reader_get_current_type (&sub) == DBUS_TYPE_BYTE);
359 #ifndef DBUS_DISABLE_ASSERT
361 unsigned char v_BYTE;
362 _dbus_type_reader_read_basic (&sub, &v_BYTE);
363 _dbus_assert (((int) v_BYTE) == field);
367 if (!_dbus_type_reader_next (&sub))
368 _dbus_assert_not_reached ("no variant field?");
370 _dbus_type_reader_recurse (&sub, &variant);
371 _dbus_assert (_dbus_type_reader_get_current_type (&variant) == type);
373 if (!_dbus_type_reader_set_basic (&variant, value, realign_root))
380 * Gets the type of the message.
382 * @param header the header
386 _dbus_header_get_message_type (DBusHeader *header)
390 type = _dbus_string_get_byte (&header->data, TYPE_OFFSET);
391 _dbus_assert (type != DBUS_MESSAGE_TYPE_INVALID);
397 * Sets the serial number of a header. This can only be done once on
400 * @param header the header
401 * @param serial the serial
404 _dbus_header_set_serial (DBusHeader *header,
405 dbus_uint32_t serial)
407 /* we use this function to set the serial on outgoing
408 * messages, and to reset the serial in dbus_message_copy;
409 * this assertion should catch a double-set on outgoing.
411 _dbus_assert (_dbus_header_get_serial (header) == 0 ||
414 _dbus_marshal_set_uint32 (&header->data,
417 _dbus_header_get_byte_order (header));
421 * See dbus_message_get_serial()
423 * @param header the header
424 * @returns the client serial
427 _dbus_header_get_serial (DBusHeader *header)
429 return _dbus_marshal_read_uint32 (&header->data,
431 _dbus_header_get_byte_order (header),
436 * Re-initializes a header that was previously initialized and never
437 * freed. After this, to make the header valid you have to call
438 * _dbus_header_create().
440 * @param header header to re-initialize
443 _dbus_header_reinit (DBusHeader *header)
445 _dbus_string_set_length (&header->data, 0);
449 _dbus_header_cache_invalidate_all (header);
453 * Initializes a header, but doesn't prepare it for use;
454 * to make the header valid, you have to call _dbus_header_create().
456 * @param header header to initialize
457 * @returns #FALSE if not enough memory
460 _dbus_header_init (DBusHeader *header)
462 if (!_dbus_string_init_preallocated (&header->data, 32))
465 _dbus_header_reinit (header);
473 * @param header the header
476 _dbus_header_free (DBusHeader *header)
478 _dbus_string_free (&header->data);
482 * Initializes dest with a copy of the given header.
483 * Resets the message serial to 0 on the copy.
485 * @param header header to copy
486 * @param dest destination for copy
487 * @returns #FALSE if not enough memory
490 _dbus_header_copy (const DBusHeader *header,
495 if (!_dbus_string_init_preallocated (&dest->data,
496 _dbus_string_get_length (&header->data)))
499 if (!_dbus_string_copy (&header->data, 0, &dest->data, 0))
501 _dbus_string_free (&dest->data);
505 /* Reset the serial */
506 _dbus_header_set_serial (dest, 0);
512 * Fills in the primary fields of the header, so the header is ready
513 * for use. #NULL may be specified for some or all of the fields to
514 * avoid adding those fields. Some combinations of fields don't make
515 * sense, and passing them in will trigger an assertion failure.
517 * @param header the header
518 * @param byte_order byte order of the header
519 * @param message_type the message type
520 * @param destination destination field or #NULL
521 * @param path path field or #NULL
522 * @param interface interface field or #NULL
523 * @param member member field or #NULL
524 * @param error_name error name or #NULL
525 * @returns #FALSE if not enough memory
528 _dbus_header_create (DBusHeader *header,
531 const char *destination,
533 const char *interface,
535 const char *error_name)
537 unsigned char v_BYTE;
538 dbus_uint32_t v_UINT32;
539 DBusTypeWriter writer;
540 DBusTypeWriter array;
542 _dbus_assert (byte_order == DBUS_LITTLE_ENDIAN ||
543 byte_order == DBUS_BIG_ENDIAN);
544 _dbus_assert (((interface || message_type != DBUS_MESSAGE_TYPE_SIGNAL) && member) ||
546 !(interface || member || error_name));
547 _dbus_assert (_dbus_string_get_length (&header->data) == 0);
549 if (!reserve_header_padding (header))
552 _dbus_type_writer_init_values_only (&writer, byte_order,
553 &_dbus_header_signature_str, 0,
555 HEADER_END_BEFORE_PADDING (header));
558 if (!_dbus_type_writer_write_basic (&writer, DBUS_TYPE_BYTE,
562 v_BYTE = message_type;
563 if (!_dbus_type_writer_write_basic (&writer, DBUS_TYPE_BYTE,
567 v_BYTE = 0; /* flags */
568 if (!_dbus_type_writer_write_basic (&writer, DBUS_TYPE_BYTE,
572 v_BYTE = DBUS_MAJOR_PROTOCOL_VERSION;
573 if (!_dbus_type_writer_write_basic (&writer, DBUS_TYPE_BYTE,
577 v_UINT32 = 0; /* body length */
578 if (!_dbus_type_writer_write_basic (&writer, DBUS_TYPE_UINT32,
582 v_UINT32 = 0; /* serial */
583 if (!_dbus_type_writer_write_basic (&writer, DBUS_TYPE_UINT32,
587 if (!_dbus_type_writer_recurse (&writer, DBUS_TYPE_ARRAY,
588 &_dbus_header_signature_str,
589 FIELDS_ARRAY_SIGNATURE_OFFSET,
593 /* Marshal all the fields (Marshall Fields?) */
597 if (!write_basic_field (&array,
598 DBUS_HEADER_FIELD_PATH,
599 DBUS_TYPE_OBJECT_PATH,
604 if (destination != NULL)
606 if (!write_basic_field (&array,
607 DBUS_HEADER_FIELD_DESTINATION,
613 if (interface != NULL)
615 if (!write_basic_field (&array,
616 DBUS_HEADER_FIELD_INTERFACE,
624 if (!write_basic_field (&array,
625 DBUS_HEADER_FIELD_MEMBER,
631 if (error_name != NULL)
633 if (!write_basic_field (&array,
634 DBUS_HEADER_FIELD_ERROR_NAME,
640 if (!_dbus_type_writer_unrecurse (&writer, &array))
643 correct_header_padding (header);
648 _dbus_string_delete (&header->data, 0,
649 _dbus_string_get_length (&header->data) - header->padding);
650 correct_header_padding (header);
656 * Given data long enough to contain the length of the message body
657 * and the fields array, check whether the data is long enough to
658 * contain the entire message (assuming the claimed lengths are
659 * accurate). Also checks that the lengths are in sanity parameters.
661 * @param max_message_length maximum length of a valid message
662 * @param validity return location for why the data is invalid if it is
663 * @param byte_order return location for byte order
664 * @param fields_array_len return location for claimed fields array length
665 * @param header_len return location for claimed header length
666 * @param body_len return location for claimed body length
667 * @param str the data
668 * @param start start of data, 8-aligned
669 * @param len length of data
670 * @returns #TRUE if the data is long enough for the claimed length, and the lengths were valid
673 _dbus_header_have_message_untrusted (int max_message_length,
674 DBusValidity *validity,
676 int *fields_array_len,
679 const DBusString *str,
684 dbus_uint32_t header_len_unsigned;
685 dbus_uint32_t fields_array_len_unsigned;
686 dbus_uint32_t body_len_unsigned;
688 _dbus_assert (start >= 0);
689 _dbus_assert (start < _DBUS_INT32_MAX / 2);
690 _dbus_assert (len >= 0);
692 _dbus_assert (start == (int) _DBUS_ALIGN_VALUE (start, 8));
694 *byte_order = _dbus_string_get_byte (str, start + BYTE_ORDER_OFFSET);
696 if (*byte_order != DBUS_LITTLE_ENDIAN && *byte_order != DBUS_BIG_ENDIAN)
698 *validity = DBUS_INVALID_BAD_BYTE_ORDER;
702 _dbus_assert (FIELDS_ARRAY_LENGTH_OFFSET + 4 <= len);
703 fields_array_len_unsigned = _dbus_marshal_read_uint32 (str, start + FIELDS_ARRAY_LENGTH_OFFSET,
706 if (fields_array_len_unsigned > (unsigned) max_message_length)
708 *validity = DBUS_INVALID_INSANE_FIELDS_ARRAY_LENGTH;
712 _dbus_assert (BODY_LENGTH_OFFSET + 4 < len);
713 body_len_unsigned = _dbus_marshal_read_uint32 (str, start + BODY_LENGTH_OFFSET,
716 if (body_len_unsigned > (unsigned) max_message_length)
718 *validity = DBUS_INVALID_INSANE_BODY_LENGTH;
722 header_len_unsigned = FIRST_FIELD_OFFSET + fields_array_len_unsigned;
723 header_len_unsigned = _DBUS_ALIGN_VALUE (header_len_unsigned, 8);
725 /* overflow should be impossible since the lengths aren't allowed to
728 _dbus_assert (max_message_length < _DBUS_INT32_MAX / 2);
729 if (body_len_unsigned + header_len_unsigned > (unsigned) max_message_length)
731 *validity = DBUS_INVALID_MESSAGE_TOO_LONG;
735 _dbus_assert (body_len_unsigned < (unsigned) _DBUS_INT32_MAX);
736 _dbus_assert (fields_array_len_unsigned < (unsigned) _DBUS_INT32_MAX);
737 _dbus_assert (header_len_unsigned < (unsigned) _DBUS_INT32_MAX);
739 *body_len = body_len_unsigned;
740 *fields_array_len = fields_array_len_unsigned;
741 *header_len = header_len_unsigned;
743 *validity = DBUS_VALID;
745 _dbus_verbose ("have %d bytes, need body %u + header %u = %u\n",
746 len, body_len_unsigned, header_len_unsigned,
747 body_len_unsigned + header_len_unsigned);
749 return (body_len_unsigned + header_len_unsigned) <= (unsigned) len;
753 check_mandatory_fields (DBusHeader *header)
755 #define REQUIRE_FIELD(name) do { if (header->fields[DBUS_HEADER_FIELD_##name].value_pos < 0) return DBUS_INVALID_MISSING_##name; } while (0)
757 switch (_dbus_header_get_message_type (header))
759 case DBUS_MESSAGE_TYPE_SIGNAL:
760 REQUIRE_FIELD (INTERFACE);
761 /* FALL THRU - signals also require the path and member */
762 case DBUS_MESSAGE_TYPE_METHOD_CALL:
763 REQUIRE_FIELD (PATH);
764 REQUIRE_FIELD (MEMBER);
766 case DBUS_MESSAGE_TYPE_ERROR:
767 REQUIRE_FIELD (ERROR_NAME);
768 REQUIRE_FIELD (REPLY_SERIAL);
770 case DBUS_MESSAGE_TYPE_METHOD_RETURN:
771 REQUIRE_FIELD (REPLY_SERIAL);
774 /* other message types allowed but ignored */
782 load_and_validate_field (DBusHeader *header,
784 DBusTypeReader *variant_reader)
788 const DBusString *value_str;
791 dbus_uint32_t v_UINT32;
793 dbus_bool_t (* string_validation_func) (const DBusString *str,
796 /* Supposed to have been checked already */
797 _dbus_assert (field <= DBUS_HEADER_FIELD_LAST);
798 _dbus_assert (field != DBUS_HEADER_FIELD_INVALID);
800 /* Before we can cache a field, we need to know it has the right type */
801 type = _dbus_type_reader_get_current_type (variant_reader);
803 _dbus_assert (_dbus_header_field_types[field].code == field);
805 expected_type = EXPECTED_TYPE_OF_FIELD (field);
806 if (type != expected_type)
808 _dbus_verbose ("Field %d should have type %d but has %d\n",
809 field, expected_type, type);
810 return DBUS_INVALID_HEADER_FIELD_HAS_WRONG_TYPE;
813 /* If the field was provided twice, we aren't happy */
814 if (header->fields[field].value_pos >= 0)
816 _dbus_verbose ("Header field %d seen a second time\n", field);
817 return DBUS_INVALID_HEADER_FIELD_APPEARS_TWICE;
820 /* Now we can cache and look at the field content */
821 _dbus_verbose ("initially caching field %d\n", field);
822 _dbus_header_cache_one (header, field, variant_reader);
824 string_validation_func = NULL;
826 /* make compiler happy that all this is initialized */
831 bad_string_code = DBUS_VALID;
833 if (expected_type == DBUS_TYPE_UINT32)
835 _dbus_header_get_field_basic (header, field, expected_type,
838 else if (expected_type == DBUS_TYPE_STRING ||
839 expected_type == DBUS_TYPE_OBJECT_PATH ||
840 expected_type == DBUS_TYPE_SIGNATURE)
842 _dbus_header_get_field_raw (header, field,
843 &value_str, &value_pos);
844 str_data_pos = _DBUS_ALIGN_VALUE (value_pos, 4) + 4;
848 _dbus_assert_not_reached ("none of the known fields should have this type");
853 case DBUS_HEADER_FIELD_DESTINATION:
854 string_validation_func = _dbus_validate_bus_name;
855 bad_string_code = DBUS_INVALID_BAD_DESTINATION;
857 case DBUS_HEADER_FIELD_INTERFACE:
858 string_validation_func = _dbus_validate_interface;
859 bad_string_code = DBUS_INVALID_BAD_INTERFACE;
861 if (_dbus_string_equal_substring (&_dbus_local_interface_str,
863 _dbus_string_get_length (&_dbus_local_interface_str),
864 value_str, str_data_pos))
866 _dbus_verbose ("Message is on the local interface\n");
867 return DBUS_INVALID_USES_LOCAL_INTERFACE;
871 case DBUS_HEADER_FIELD_MEMBER:
872 string_validation_func = _dbus_validate_member;
873 bad_string_code = DBUS_INVALID_BAD_MEMBER;
876 case DBUS_HEADER_FIELD_ERROR_NAME:
877 string_validation_func = _dbus_validate_error_name;
878 bad_string_code = DBUS_INVALID_BAD_ERROR_NAME;
881 case DBUS_HEADER_FIELD_SENDER:
882 string_validation_func = _dbus_validate_bus_name;
883 bad_string_code = DBUS_INVALID_BAD_SENDER;
886 case DBUS_HEADER_FIELD_PATH:
887 /* OBJECT_PATH was validated generically due to its type */
888 string_validation_func = NULL;
890 if (_dbus_string_equal_substring (&_dbus_local_path_str,
892 _dbus_string_get_length (&_dbus_local_path_str),
893 value_str, str_data_pos))
895 _dbus_verbose ("Message is from the local path\n");
896 return DBUS_INVALID_USES_LOCAL_PATH;
900 case DBUS_HEADER_FIELD_REPLY_SERIAL:
904 return DBUS_INVALID_BAD_SERIAL;
908 case DBUS_HEADER_FIELD_UNIX_FDS:
909 /* Every value makes sense */
912 case DBUS_HEADER_FIELD_SIGNATURE:
913 /* SIGNATURE validated generically due to its type */
914 string_validation_func = NULL;
918 _dbus_assert_not_reached ("unknown field shouldn't be seen here");
922 if (string_validation_func)
926 _dbus_assert (bad_string_code != DBUS_VALID);
928 len = _dbus_marshal_read_uint32 (value_str, value_pos,
929 _dbus_header_get_byte_order (header),
933 _dbus_verbose ("Validating string header field; code %d if fails\n",
936 if (!(*string_validation_func) (value_str, str_data_pos, len))
937 return bad_string_code;
944 * Creates a message header from potentially-untrusted data. The
945 * return value is #TRUE if there was enough memory and the data was
946 * valid. If it returns #TRUE, the header will be created. If it
947 * returns #FALSE and *validity == #DBUS_VALIDITY_UNKNOWN_OOM_ERROR,
948 * then there wasn't enough memory. If it returns #FALSE
949 * and *validity != #DBUS_VALIDITY_UNKNOWN_OOM_ERROR then the data was
952 * The byte_order, fields_array_len, and body_len args should be from
953 * _dbus_header_have_message_untrusted(). Validation performed in
954 * _dbus_header_have_message_untrusted() is assumed to have been
957 * @param header the header (must be initialized)
958 * @param mode whether to do validation
959 * @param validity return location for invalidity reason
960 * @param byte_order byte order from header
961 * @param fields_array_len claimed length of fields array
962 * @param body_len claimed length of body
963 * @param header_len claimed length of header
964 * @param str a string
965 * @param start start of header, 8-aligned
966 * @param len length of string to look at
967 * @returns #FALSE if no memory or data was invalid, #TRUE otherwise
970 _dbus_header_load (DBusHeader *header,
971 DBusValidationMode mode,
972 DBusValidity *validity,
974 int fields_array_len,
977 const DBusString *str,
983 DBusTypeReader reader;
984 DBusTypeReader array_reader;
985 unsigned char v_byte;
986 dbus_uint32_t v_uint32;
987 dbus_uint32_t serial;
992 _dbus_assert (start == (int) _DBUS_ALIGN_VALUE (start, 8));
993 _dbus_assert (header_len <= len);
994 _dbus_assert (_dbus_string_get_length (&header->data) == 0);
996 if (!_dbus_string_copy_len (str, start, header_len, &header->data, 0))
998 _dbus_verbose ("Failed to copy buffer into new header\n");
999 *validity = DBUS_VALIDITY_UNKNOWN_OOM_ERROR;
1003 if (mode == DBUS_VALIDATION_MODE_WE_TRUST_THIS_DATA_ABSOLUTELY)
1005 leftover = len - header_len - body_len - start;
1009 v = _dbus_validate_body_with_reason (&_dbus_header_signature_str, 0,
1014 if (v != DBUS_VALID)
1021 _dbus_assert (leftover < len);
1023 padding_len = header_len - (FIRST_FIELD_OFFSET + fields_array_len);
1024 padding_start = start + FIRST_FIELD_OFFSET + fields_array_len;
1025 _dbus_assert (start + header_len == (int) _DBUS_ALIGN_VALUE (padding_start, 8));
1026 _dbus_assert (start + header_len == padding_start + padding_len);
1028 if (mode != DBUS_VALIDATION_MODE_WE_TRUST_THIS_DATA_ABSOLUTELY)
1030 if (!_dbus_string_validate_nul (str, padding_start, padding_len))
1032 *validity = DBUS_INVALID_ALIGNMENT_PADDING_NOT_NUL;
1037 header->padding = padding_len;
1039 if (mode == DBUS_VALIDATION_MODE_WE_TRUST_THIS_DATA_ABSOLUTELY)
1041 *validity = DBUS_VALID;
1045 /* We now know the data is well-formed, but we have to check that
1049 _dbus_type_reader_init (&reader,
1051 &_dbus_header_signature_str, 0,
1055 _dbus_assert (_dbus_type_reader_get_current_type (&reader) == DBUS_TYPE_BYTE);
1056 _dbus_assert (_dbus_type_reader_get_value_pos (&reader) == BYTE_ORDER_OFFSET);
1057 _dbus_type_reader_read_basic (&reader, &v_byte);
1058 _dbus_type_reader_next (&reader);
1060 _dbus_assert (v_byte == byte_order);
1063 _dbus_assert (_dbus_type_reader_get_current_type (&reader) == DBUS_TYPE_BYTE);
1064 _dbus_assert (_dbus_type_reader_get_value_pos (&reader) == TYPE_OFFSET);
1065 _dbus_type_reader_read_basic (&reader, &v_byte);
1066 _dbus_type_reader_next (&reader);
1068 /* unknown message types are supposed to be ignored, so only validation here is
1069 * that it isn't invalid
1071 if (v_byte == DBUS_MESSAGE_TYPE_INVALID)
1073 *validity = DBUS_INVALID_BAD_MESSAGE_TYPE;
1078 _dbus_assert (_dbus_type_reader_get_current_type (&reader) == DBUS_TYPE_BYTE);
1079 _dbus_assert (_dbus_type_reader_get_value_pos (&reader) == FLAGS_OFFSET);
1080 _dbus_type_reader_read_basic (&reader, &v_byte);
1081 _dbus_type_reader_next (&reader);
1083 /* unknown flags should be ignored */
1085 /* PROTOCOL VERSION */
1086 _dbus_assert (_dbus_type_reader_get_current_type (&reader) == DBUS_TYPE_BYTE);
1087 _dbus_assert (_dbus_type_reader_get_value_pos (&reader) == VERSION_OFFSET);
1088 _dbus_type_reader_read_basic (&reader, &v_byte);
1089 _dbus_type_reader_next (&reader);
1091 if (v_byte != DBUS_MAJOR_PROTOCOL_VERSION)
1093 *validity = DBUS_INVALID_BAD_PROTOCOL_VERSION;
1098 _dbus_assert (_dbus_type_reader_get_current_type (&reader) == DBUS_TYPE_UINT32);
1099 _dbus_assert (_dbus_type_reader_get_value_pos (&reader) == BODY_LENGTH_OFFSET);
1100 _dbus_type_reader_read_basic (&reader, &v_uint32);
1101 _dbus_type_reader_next (&reader);
1103 _dbus_assert (body_len == (signed) v_uint32);
1106 _dbus_assert (_dbus_type_reader_get_current_type (&reader) == DBUS_TYPE_UINT32);
1107 _dbus_assert (_dbus_type_reader_get_value_pos (&reader) == SERIAL_OFFSET);
1108 _dbus_type_reader_read_basic (&reader, &serial);
1109 _dbus_type_reader_next (&reader);
1113 *validity = DBUS_INVALID_BAD_SERIAL;
1117 _dbus_assert (_dbus_type_reader_get_current_type (&reader) == DBUS_TYPE_ARRAY);
1118 _dbus_assert (_dbus_type_reader_get_value_pos (&reader) == FIELDS_ARRAY_LENGTH_OFFSET);
1120 _dbus_type_reader_recurse (&reader, &array_reader);
1121 while (_dbus_type_reader_get_current_type (&array_reader) != DBUS_TYPE_INVALID)
1123 DBusTypeReader struct_reader;
1124 DBusTypeReader variant_reader;
1125 unsigned char field_code;
1127 _dbus_assert (_dbus_type_reader_get_current_type (&array_reader) == DBUS_TYPE_STRUCT);
1129 _dbus_type_reader_recurse (&array_reader, &struct_reader);
1131 _dbus_assert (_dbus_type_reader_get_current_type (&struct_reader) == DBUS_TYPE_BYTE);
1132 _dbus_type_reader_read_basic (&struct_reader, &field_code);
1133 _dbus_type_reader_next (&struct_reader);
1135 if (field_code == DBUS_HEADER_FIELD_INVALID)
1137 _dbus_verbose ("invalid header field code\n");
1138 *validity = DBUS_INVALID_HEADER_FIELD_CODE;
1142 if (field_code > DBUS_HEADER_FIELD_LAST)
1144 _dbus_verbose ("unknown header field code %d, skipping\n",
1149 _dbus_assert (_dbus_type_reader_get_current_type (&struct_reader) == DBUS_TYPE_VARIANT);
1150 _dbus_type_reader_recurse (&struct_reader, &variant_reader);
1152 v = load_and_validate_field (header, field_code, &variant_reader);
1153 if (v != DBUS_VALID)
1155 _dbus_verbose ("Field %d was invalid\n", field_code);
1161 _dbus_type_reader_next (&array_reader);
1164 /* Anything we didn't fill in is now known not to exist */
1166 while (i <= DBUS_HEADER_FIELD_LAST)
1168 if (header->fields[i].value_pos == _DBUS_HEADER_FIELD_VALUE_UNKNOWN)
1169 header->fields[i].value_pos = _DBUS_HEADER_FIELD_VALUE_NONEXISTENT;
1173 v = check_mandatory_fields (header);
1174 if (v != DBUS_VALID)
1176 _dbus_verbose ("Mandatory fields were missing, code %d\n", v);
1181 *validity = DBUS_VALID;
1185 _dbus_string_set_length (&header->data, 0);
1190 * Fills in the correct body length.
1192 * @param header the header
1193 * @param body_len the length of the body
1196 _dbus_header_update_lengths (DBusHeader *header,
1199 _dbus_marshal_set_uint32 (&header->data,
1202 _dbus_header_get_byte_order (header));
1206 * Try to find the given field.
1208 * @param header the header
1209 * @param field the field code
1210 * @param reader a type reader; on success this is left pointing at the struct
1211 * (uv) for the field, while on failure it is left pointing into empty space
1212 * at the end of the header fields
1213 * @param realign_root another type reader; on success or failure it is left
1214 * pointing to the beginning of the array of fields (i.e. the thing that might
1216 * @returns #TRUE on success
1219 find_field_for_modification (DBusHeader *header,
1221 DBusTypeReader *reader,
1222 DBusTypeReader *realign_root)
1228 _dbus_type_reader_init (realign_root,
1229 _dbus_header_get_byte_order (header),
1230 &_dbus_header_signature_str,
1231 FIELDS_ARRAY_SIGNATURE_OFFSET,
1233 FIELDS_ARRAY_LENGTH_OFFSET);
1235 _dbus_type_reader_recurse (realign_root, reader);
1237 while (_dbus_type_reader_get_current_type (reader) != DBUS_TYPE_INVALID)
1240 unsigned char field_code;
1242 _dbus_type_reader_recurse (reader, &sub);
1244 _dbus_assert (_dbus_type_reader_get_current_type (&sub) == DBUS_TYPE_BYTE);
1245 _dbus_type_reader_read_basic (&sub, &field_code);
1247 if (field_code == (unsigned) field)
1249 _dbus_assert (_dbus_type_reader_get_current_type (reader) == DBUS_TYPE_STRUCT);
1254 _dbus_type_reader_next (reader);
1262 * Sets the value of a field with basic type. If the value is a string
1263 * value, it isn't allowed to be #NULL. If the field doesn't exist,
1264 * it will be created.
1266 * @param header the header
1267 * @param field the field to set
1268 * @param type the type of the value
1269 * @param value the value as for _dbus_marshal_set_basic()
1270 * @returns #FALSE if no memory
1273 _dbus_header_set_field_basic (DBusHeader *header,
1278 _dbus_assert (field <= DBUS_HEADER_FIELD_LAST);
1280 if (!reserve_header_padding (header))
1283 /* If the field exists we set, otherwise we append */
1284 if (_dbus_header_cache_check (header, field))
1286 DBusTypeReader reader;
1287 DBusTypeReader realign_root;
1289 if (!find_field_for_modification (header, field,
1290 &reader, &realign_root))
1291 _dbus_assert_not_reached ("field was marked present in cache but wasn't found");
1293 if (!set_basic_field (&reader, field, type, value, &realign_root))
1298 DBusTypeWriter writer;
1299 DBusTypeWriter array;
1301 _dbus_type_writer_init_values_only (&writer,
1302 _dbus_header_get_byte_order (header),
1303 &_dbus_header_signature_str,
1304 FIELDS_ARRAY_SIGNATURE_OFFSET,
1306 FIELDS_ARRAY_LENGTH_OFFSET);
1308 /* recurse into array without creating a new length, and jump to
1311 if (!_dbus_type_writer_append_array (&writer,
1312 &_dbus_header_signature_str,
1313 FIELDS_ARRAY_ELEMENT_SIGNATURE_OFFSET,
1315 _dbus_assert_not_reached ("recurse into ARRAY should not have used memory");
1317 _dbus_assert (array.u.array.len_pos == FIELDS_ARRAY_LENGTH_OFFSET);
1318 _dbus_assert (array.u.array.start_pos == FIRST_FIELD_OFFSET);
1319 _dbus_assert (array.value_pos == HEADER_END_BEFORE_PADDING (header));
1321 if (!write_basic_field (&array,
1322 field, type, value))
1325 if (!_dbus_type_writer_unrecurse (&writer, &array))
1326 _dbus_assert_not_reached ("unrecurse from ARRAY should not have used memory");
1329 correct_header_padding (header);
1331 /* We could be smarter about this (only invalidate fields after the
1332 * one we modified, or even only if the one we modified changed
1333 * length). But this hack is a start.
1335 _dbus_header_cache_invalidate_all (header);
1341 * Gets the value of a field with basic type. If the field
1342 * doesn't exist, returns #FALSE, otherwise returns #TRUE.
1344 * @param header the header
1345 * @param field the field to get
1346 * @param type the type of the value
1347 * @param value the value as for _dbus_marshal_read_basic()
1348 * @returns #FALSE if the field doesn't exist
1351 _dbus_header_get_field_basic (DBusHeader *header,
1356 _dbus_assert (field != DBUS_HEADER_FIELD_INVALID);
1357 _dbus_assert (field <= DBUS_HEADER_FIELD_LAST);
1358 _dbus_assert (_dbus_header_field_types[field].code == field);
1359 /* in light of this you might ask why the type is passed in;
1360 * the only rationale I can think of is so the caller has
1361 * to specify its expectation and breaks if we change it
1363 _dbus_assert (type == EXPECTED_TYPE_OF_FIELD (field));
1365 if (!_dbus_header_cache_check (header, field))
1368 _dbus_assert (header->fields[field].value_pos >= 0);
1370 _dbus_marshal_read_basic (&header->data,
1371 header->fields[field].value_pos,
1372 type, value, _dbus_header_get_byte_order (header),
1379 * Gets the raw marshaled data for a field. If the field doesn't
1380 * exist, returns #FALSE, otherwise returns #TRUE. Returns the start
1381 * of the marshaled data, i.e. usually the byte where the length
1382 * starts (for strings and arrays) or for basic types just the value
1385 * @param header the header
1386 * @param field the field to get
1387 * @param str return location for the data string
1388 * @param pos return location for start of field value
1389 * @returns #FALSE if the field doesn't exist
1392 _dbus_header_get_field_raw (DBusHeader *header,
1394 const DBusString **str,
1397 if (!_dbus_header_cache_check (header, field))
1401 *str = &header->data;
1403 *pos = header->fields[field].value_pos;
1409 * Deletes a field, if it exists.
1411 * @param header the header
1412 * @param field the field to delete
1413 * @returns #FALSE if no memory
1416 _dbus_header_delete_field (DBusHeader *header,
1419 DBusTypeReader reader;
1420 DBusTypeReader realign_root;
1422 if (_dbus_header_cache_known_nonexistent (header, field))
1423 return TRUE; /* nothing to do */
1425 /* Scan to the field we want, delete and realign, reappend
1426 * padding. Field may turn out not to exist.
1428 if (!find_field_for_modification (header, field,
1429 &reader, &realign_root))
1430 return TRUE; /* nothing to do */
1432 if (!reserve_header_padding (header))
1435 if (!_dbus_type_reader_delete (&reader,
1439 correct_header_padding (header);
1441 _dbus_header_cache_invalidate_all (header);
1443 _dbus_assert (!_dbus_header_cache_check (header, field)); /* Expensive assertion ... */
1449 * Toggles a message flag bit, turning on the bit if value = TRUE and
1450 * flipping it off if value = FALSE.
1452 * @param header the header
1453 * @param flag the message flag to toggle
1454 * @param value toggle on or off
1457 _dbus_header_toggle_flag (DBusHeader *header,
1461 unsigned char *flags_p;
1463 flags_p = _dbus_string_get_data_len (&header->data, FLAGS_OFFSET, 1);
1472 * Gets a message flag bit, returning TRUE if the bit is set.
1474 * @param header the header
1475 * @param flag the message flag to get
1476 * @returns #TRUE if the flag is set
1479 _dbus_header_get_flag (DBusHeader *header,
1482 const unsigned char *flags_p;
1484 flags_p = _dbus_string_get_const_data_len (&header->data, FLAGS_OFFSET, 1);
1486 return (*flags_p & flag) != 0;
1490 * Swaps the header into the given order if required.
1492 * @param header the header
1493 * @param new_order the new byte order
1496 _dbus_header_byteswap (DBusHeader *header,
1501 byte_order = _dbus_header_get_byte_order (header);
1503 if (byte_order == new_order)
1506 _dbus_marshal_byteswap (&_dbus_header_signature_str,
1511 _dbus_string_set_byte (&header->data, BYTE_ORDER_OFFSET, new_order);