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,
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 type the type of the value
280 * @param value the value as for _dbus_marshal_set_basic()
281 * @returns #FALSE if no memory
284 write_basic_field (DBusTypeWriter *writer,
290 DBusTypeWriter variant;
293 unsigned char field_byte;
294 DBusString contained_type;
297 start = writer->value_pos;
298 padding = _dbus_string_get_length (writer->value_str) - start;
300 if (!_dbus_type_writer_recurse (writer, DBUS_TYPE_STRUCT,
305 if (!_dbus_type_writer_write_basic (&sub, DBUS_TYPE_BYTE,
311 _dbus_string_init_const_len (&contained_type, buf, 1);
313 if (!_dbus_type_writer_recurse (&sub, DBUS_TYPE_VARIANT,
314 &contained_type, 0, &variant))
317 if (!_dbus_type_writer_write_basic (&variant, type, value))
320 if (!_dbus_type_writer_unrecurse (&sub, &variant))
323 if (!_dbus_type_writer_unrecurse (writer, &sub))
329 _dbus_string_delete (writer->value_str,
331 _dbus_string_get_length (writer->value_str) - start - padding);
336 * Sets a struct of { byte, variant } with the given basic type.
338 * @param reader the reader (should be iterating over the array pointing at the field to set)
339 * @param type the type of the value
340 * @param value the value as for _dbus_marshal_set_basic()
341 * @param realign_root where to realign from
342 * @returns #FALSE if no memory
345 set_basic_field (DBusTypeReader *reader,
349 const DBusTypeReader *realign_root)
352 DBusTypeReader variant;
354 _dbus_type_reader_recurse (reader, &sub);
356 _dbus_assert (_dbus_type_reader_get_current_type (&sub) == DBUS_TYPE_BYTE);
357 #ifndef DBUS_DISABLE_ASSERT
359 unsigned char v_BYTE;
360 _dbus_type_reader_read_basic (&sub, &v_BYTE);
361 _dbus_assert (((int) v_BYTE) == field);
365 if (!_dbus_type_reader_next (&sub))
366 _dbus_assert_not_reached ("no variant field?");
368 _dbus_type_reader_recurse (&sub, &variant);
369 _dbus_assert (_dbus_type_reader_get_current_type (&variant) == type);
371 if (!_dbus_type_reader_set_basic (&variant, value, realign_root))
378 * Gets the type of the message.
380 * @param header the header
384 _dbus_header_get_message_type (DBusHeader *header)
388 type = _dbus_string_get_byte (&header->data, TYPE_OFFSET);
389 _dbus_assert (type != DBUS_MESSAGE_TYPE_INVALID);
395 * Sets the serial number of a header. This can only be done once on
398 * @param header the header
399 * @param serial the serial
402 _dbus_header_set_serial (DBusHeader *header,
403 dbus_uint32_t serial)
405 /* we use this function to set the serial on outgoing
406 * messages, and to reset the serial in dbus_message_copy;
407 * this assertion should catch a double-set on outgoing.
409 _dbus_assert (_dbus_header_get_serial (header) == 0 ||
412 _dbus_marshal_set_uint32 (&header->data,
419 * See dbus_message_get_serial()
421 * @param header the header
422 * @returns the client serial
425 _dbus_header_get_serial (DBusHeader *header)
427 return _dbus_marshal_read_uint32 (&header->data,
434 * Re-initializes a header that was previously initialized and never
435 * freed. After this, to make the header valid you have to call
436 * _dbus_header_create().
438 * @param header header to re-initialize
439 * @param byte_order byte order of the header
442 _dbus_header_reinit (DBusHeader *header,
445 _dbus_string_set_length (&header->data, 0);
447 header->byte_order = byte_order;
450 _dbus_header_cache_invalidate_all (header);
454 * Initializes a header, but doesn't prepare it for use;
455 * to make the header valid, you have to call _dbus_header_create().
457 * @param header header to initialize
458 * @param byte_order byte order of the header
459 * @returns #FALSE if not enough memory
462 _dbus_header_init (DBusHeader *header,
465 if (!_dbus_string_init_preallocated (&header->data, 32))
468 _dbus_header_reinit (header, byte_order);
476 * @param header the header
479 _dbus_header_free (DBusHeader *header)
481 _dbus_string_free (&header->data);
485 * Initializes dest with a copy of the given header.
486 * Resets the message serial to 0 on the copy.
488 * @param header header to copy
489 * @param dest destination for copy
490 * @returns #FALSE if not enough memory
493 _dbus_header_copy (const DBusHeader *header,
498 if (!_dbus_string_init_preallocated (&dest->data,
499 _dbus_string_get_length (&header->data)))
502 if (!_dbus_string_copy (&header->data, 0, &dest->data, 0))
504 _dbus_string_free (&dest->data);
508 /* Reset the serial */
509 _dbus_header_set_serial (dest, 0);
515 * Fills in the primary fields of the header, so the header is ready
516 * for use. #NULL may be specified for some or all of the fields to
517 * avoid adding those fields. Some combinations of fields don't make
518 * sense, and passing them in will trigger an assertion failure.
520 * @param header the header
521 * @param message_type the message type
522 * @param destination destination field or #NULL
523 * @param path path field or #NULL
524 * @param interface interface field or #NULL
525 * @param member member field or #NULL
526 * @param error_name error name or #NULL
527 * @returns #FALSE if not enough memory
530 _dbus_header_create (DBusHeader *header,
532 const char *destination,
534 const char *interface,
536 const char *error_name)
538 unsigned char v_BYTE;
539 dbus_uint32_t v_UINT32;
540 DBusTypeWriter writer;
541 DBusTypeWriter array;
543 _dbus_assert (((interface || message_type != DBUS_MESSAGE_TYPE_SIGNAL) && member) ||
545 !(interface || member || error_name));
546 _dbus_assert (_dbus_string_get_length (&header->data) == 0);
548 if (!reserve_header_padding (header))
551 _dbus_type_writer_init_values_only (&writer, header->byte_order,
552 &_dbus_header_signature_str, 0,
554 HEADER_END_BEFORE_PADDING (header));
556 v_BYTE = header->byte_order;
557 if (!_dbus_type_writer_write_basic (&writer, DBUS_TYPE_BYTE,
561 v_BYTE = message_type;
562 if (!_dbus_type_writer_write_basic (&writer, DBUS_TYPE_BYTE,
566 v_BYTE = 0; /* flags */
567 if (!_dbus_type_writer_write_basic (&writer, DBUS_TYPE_BYTE,
571 v_BYTE = DBUS_MAJOR_PROTOCOL_VERSION;
572 if (!_dbus_type_writer_write_basic (&writer, DBUS_TYPE_BYTE,
576 v_UINT32 = 0; /* body length */
577 if (!_dbus_type_writer_write_basic (&writer, DBUS_TYPE_UINT32,
581 v_UINT32 = 0; /* serial */
582 if (!_dbus_type_writer_write_basic (&writer, DBUS_TYPE_UINT32,
586 if (!_dbus_type_writer_recurse (&writer, DBUS_TYPE_ARRAY,
587 &_dbus_header_signature_str,
588 FIELDS_ARRAY_SIGNATURE_OFFSET,
592 /* Marshal all the fields (Marshall Fields?) */
596 if (!write_basic_field (&array,
597 DBUS_HEADER_FIELD_PATH,
598 DBUS_TYPE_OBJECT_PATH,
603 if (destination != NULL)
605 if (!write_basic_field (&array,
606 DBUS_HEADER_FIELD_DESTINATION,
612 if (interface != NULL)
614 if (!write_basic_field (&array,
615 DBUS_HEADER_FIELD_INTERFACE,
623 if (!write_basic_field (&array,
624 DBUS_HEADER_FIELD_MEMBER,
630 if (error_name != NULL)
632 if (!write_basic_field (&array,
633 DBUS_HEADER_FIELD_ERROR_NAME,
639 if (!_dbus_type_writer_unrecurse (&writer, &array))
642 correct_header_padding (header);
647 _dbus_string_delete (&header->data, 0,
648 _dbus_string_get_length (&header->data) - header->padding);
649 correct_header_padding (header);
655 * Given data long enough to contain the length of the message body
656 * and the fields array, check whether the data is long enough to
657 * contain the entire message (assuming the claimed lengths are
658 * accurate). Also checks that the lengths are in sanity parameters.
660 * @param max_message_length maximum length of a valid message
661 * @param validity return location for why the data is invalid if it is
662 * @param byte_order return location for byte order
663 * @param fields_array_len return location for claimed fields array length
664 * @param header_len return location for claimed header length
665 * @param body_len return location for claimed body length
666 * @param str the data
667 * @param start start of data, 8-aligned
668 * @param len length of data
669 * @returns #TRUE if the data is long enough for the claimed length, and the lengths were valid
672 _dbus_header_have_message_untrusted (int max_message_length,
673 DBusValidity *validity,
675 int *fields_array_len,
678 const DBusString *str,
683 dbus_uint32_t header_len_unsigned;
684 dbus_uint32_t fields_array_len_unsigned;
685 dbus_uint32_t body_len_unsigned;
687 _dbus_assert (start >= 0);
688 _dbus_assert (start < _DBUS_INT32_MAX / 2);
689 _dbus_assert (len >= 0);
691 _dbus_assert (start == (int) _DBUS_ALIGN_VALUE (start, 8));
693 *byte_order = _dbus_string_get_byte (str, start + BYTE_ORDER_OFFSET);
695 if (*byte_order != DBUS_LITTLE_ENDIAN && *byte_order != DBUS_BIG_ENDIAN)
697 *validity = DBUS_INVALID_BAD_BYTE_ORDER;
701 _dbus_assert (FIELDS_ARRAY_LENGTH_OFFSET + 4 <= len);
702 fields_array_len_unsigned = _dbus_marshal_read_uint32 (str, start + FIELDS_ARRAY_LENGTH_OFFSET,
705 if (fields_array_len_unsigned > (unsigned) max_message_length)
707 *validity = DBUS_INVALID_INSANE_FIELDS_ARRAY_LENGTH;
711 _dbus_assert (BODY_LENGTH_OFFSET + 4 < len);
712 body_len_unsigned = _dbus_marshal_read_uint32 (str, start + BODY_LENGTH_OFFSET,
715 if (body_len_unsigned > (unsigned) max_message_length)
717 *validity = DBUS_INVALID_INSANE_BODY_LENGTH;
721 header_len_unsigned = FIRST_FIELD_OFFSET + fields_array_len_unsigned;
722 header_len_unsigned = _DBUS_ALIGN_VALUE (header_len_unsigned, 8);
724 /* overflow should be impossible since the lengths aren't allowed to
727 _dbus_assert (max_message_length < _DBUS_INT32_MAX / 2);
728 if (body_len_unsigned + header_len_unsigned > (unsigned) max_message_length)
730 *validity = DBUS_INVALID_MESSAGE_TOO_LONG;
734 _dbus_assert (body_len_unsigned < (unsigned) _DBUS_INT32_MAX);
735 _dbus_assert (fields_array_len_unsigned < (unsigned) _DBUS_INT32_MAX);
736 _dbus_assert (header_len_unsigned < (unsigned) _DBUS_INT32_MAX);
738 *body_len = body_len_unsigned;
739 *fields_array_len = fields_array_len_unsigned;
740 *header_len = header_len_unsigned;
742 *validity = DBUS_VALID;
744 _dbus_verbose ("have %d bytes, need body %u + header %u = %u\n",
745 len, body_len_unsigned, header_len_unsigned,
746 body_len_unsigned + header_len_unsigned);
748 return (body_len_unsigned + header_len_unsigned) <= (unsigned) len;
752 check_mandatory_fields (DBusHeader *header)
754 #define REQUIRE_FIELD(name) do { if (header->fields[DBUS_HEADER_FIELD_##name].value_pos < 0) return DBUS_INVALID_MISSING_##name; } while (0)
756 switch (_dbus_header_get_message_type (header))
758 case DBUS_MESSAGE_TYPE_SIGNAL:
759 REQUIRE_FIELD (INTERFACE);
760 /* FALL THRU - signals also require the path and member */
761 case DBUS_MESSAGE_TYPE_METHOD_CALL:
762 REQUIRE_FIELD (PATH);
763 REQUIRE_FIELD (MEMBER);
765 case DBUS_MESSAGE_TYPE_ERROR:
766 REQUIRE_FIELD (ERROR_NAME);
767 REQUIRE_FIELD (REPLY_SERIAL);
769 case DBUS_MESSAGE_TYPE_METHOD_RETURN:
770 REQUIRE_FIELD (REPLY_SERIAL);
773 /* other message types allowed but ignored */
781 load_and_validate_field (DBusHeader *header,
783 DBusTypeReader *variant_reader)
787 const DBusString *value_str;
790 dbus_uint32_t v_UINT32;
792 dbus_bool_t (* string_validation_func) (const DBusString *str,
795 /* Supposed to have been checked already */
796 _dbus_assert (field <= DBUS_HEADER_FIELD_LAST);
797 _dbus_assert (field != DBUS_HEADER_FIELD_INVALID);
799 /* Before we can cache a field, we need to know it has the right type */
800 type = _dbus_type_reader_get_current_type (variant_reader);
802 _dbus_assert (_dbus_header_field_types[field].code == field);
804 expected_type = EXPECTED_TYPE_OF_FIELD (field);
805 if (type != expected_type)
807 _dbus_verbose ("Field %d should have type %d but has %d\n",
808 field, expected_type, type);
809 return DBUS_INVALID_HEADER_FIELD_HAS_WRONG_TYPE;
812 /* If the field was provided twice, we aren't happy */
813 if (header->fields[field].value_pos >= 0)
815 _dbus_verbose ("Header field %d seen a second time\n", field);
816 return DBUS_INVALID_HEADER_FIELD_APPEARS_TWICE;
819 /* Now we can cache and look at the field content */
820 _dbus_verbose ("initially caching field %d\n", field);
821 _dbus_header_cache_one (header, field, variant_reader);
823 string_validation_func = NULL;
825 /* make compiler happy that all this is initialized */
830 bad_string_code = DBUS_VALID;
832 if (expected_type == DBUS_TYPE_UINT32)
834 _dbus_header_get_field_basic (header, field, expected_type,
837 else if (expected_type == DBUS_TYPE_STRING ||
838 expected_type == DBUS_TYPE_OBJECT_PATH ||
839 expected_type == DBUS_TYPE_SIGNATURE)
841 _dbus_header_get_field_raw (header, field,
842 &value_str, &value_pos);
843 str_data_pos = _DBUS_ALIGN_VALUE (value_pos, 4) + 4;
847 _dbus_assert_not_reached ("none of the known fields should have this type");
852 case DBUS_HEADER_FIELD_DESTINATION:
853 string_validation_func = _dbus_validate_bus_name;
854 bad_string_code = DBUS_INVALID_BAD_DESTINATION;
856 case DBUS_HEADER_FIELD_INTERFACE:
857 string_validation_func = _dbus_validate_interface;
858 bad_string_code = DBUS_INVALID_BAD_INTERFACE;
860 if (_dbus_string_equal_substring (&_dbus_local_interface_str,
862 _dbus_string_get_length (&_dbus_local_interface_str),
863 value_str, str_data_pos))
865 _dbus_verbose ("Message is on the local interface\n");
866 return DBUS_INVALID_USES_LOCAL_INTERFACE;
870 case DBUS_HEADER_FIELD_MEMBER:
871 string_validation_func = _dbus_validate_member;
872 bad_string_code = DBUS_INVALID_BAD_MEMBER;
875 case DBUS_HEADER_FIELD_ERROR_NAME:
876 string_validation_func = _dbus_validate_error_name;
877 bad_string_code = DBUS_INVALID_BAD_ERROR_NAME;
880 case DBUS_HEADER_FIELD_SENDER:
881 string_validation_func = _dbus_validate_bus_name;
882 bad_string_code = DBUS_INVALID_BAD_SENDER;
885 case DBUS_HEADER_FIELD_PATH:
886 /* OBJECT_PATH was validated generically due to its type */
887 string_validation_func = NULL;
889 if (_dbus_string_equal_substring (&_dbus_local_path_str,
891 _dbus_string_get_length (&_dbus_local_path_str),
892 value_str, str_data_pos))
894 _dbus_verbose ("Message is from the local path\n");
895 return DBUS_INVALID_USES_LOCAL_PATH;
899 case DBUS_HEADER_FIELD_REPLY_SERIAL:
903 return DBUS_INVALID_BAD_SERIAL;
907 case DBUS_HEADER_FIELD_UNIX_FDS:
908 /* Every value makes sense */
911 case DBUS_HEADER_FIELD_SIGNATURE:
912 /* SIGNATURE validated generically due to its type */
913 string_validation_func = NULL;
917 _dbus_assert_not_reached ("unknown field shouldn't be seen here");
921 if (string_validation_func)
925 _dbus_assert (bad_string_code != DBUS_VALID);
927 len = _dbus_marshal_read_uint32 (value_str, value_pos,
928 header->byte_order, NULL);
931 _dbus_verbose ("Validating string header field; code %d if fails\n",
934 if (!(*string_validation_func) (value_str, str_data_pos, len))
935 return bad_string_code;
942 * Creates a message header from potentially-untrusted data. The
943 * return value is #TRUE if there was enough memory and the data was
944 * valid. If it returns #TRUE, the header will be created. If it
945 * returns #FALSE and *validity == #DBUS_VALIDITY_UNKNOWN_OOM_ERROR,
946 * then there wasn't enough memory. If it returns #FALSE
947 * and *validity != #DBUS_VALIDITY_UNKNOWN_OOM_ERROR then the data was
950 * The byte_order, fields_array_len, and body_len args should be from
951 * _dbus_header_have_message_untrusted(). Validation performed in
952 * _dbus_header_have_message_untrusted() is assumed to have been
955 * @param header the header (must be initialized)
956 * @param mode whether to do validation
957 * @param validity return location for invalidity reason
958 * @param byte_order byte order from header
959 * @param fields_array_len claimed length of fields array
960 * @param body_len claimed length of body
961 * @param header_len claimed length of header
962 * @param str a string
963 * @param start start of header, 8-aligned
964 * @param len length of string to look at
965 * @returns #FALSE if no memory or data was invalid, #TRUE otherwise
968 _dbus_header_load (DBusHeader *header,
969 DBusValidationMode mode,
970 DBusValidity *validity,
972 int fields_array_len,
975 const DBusString *str,
981 DBusTypeReader reader;
982 DBusTypeReader array_reader;
983 unsigned char v_byte;
984 dbus_uint32_t v_uint32;
985 dbus_uint32_t serial;
990 _dbus_assert (start == (int) _DBUS_ALIGN_VALUE (start, 8));
991 _dbus_assert (header_len <= len);
992 _dbus_assert (_dbus_string_get_length (&header->data) == 0);
994 if (!_dbus_string_copy_len (str, start, header_len, &header->data, 0))
996 _dbus_verbose ("Failed to copy buffer into new header\n");
997 *validity = DBUS_VALIDITY_UNKNOWN_OOM_ERROR;
1001 if (mode == DBUS_VALIDATION_MODE_WE_TRUST_THIS_DATA_ABSOLUTELY)
1003 leftover = len - header_len - body_len - start;
1007 v = _dbus_validate_body_with_reason (&_dbus_header_signature_str, 0,
1012 if (v != DBUS_VALID)
1019 _dbus_assert (leftover < len);
1021 padding_len = header_len - (FIRST_FIELD_OFFSET + fields_array_len);
1022 padding_start = start + FIRST_FIELD_OFFSET + fields_array_len;
1023 _dbus_assert (start + header_len == (int) _DBUS_ALIGN_VALUE (padding_start, 8));
1024 _dbus_assert (start + header_len == padding_start + padding_len);
1026 if (mode != DBUS_VALIDATION_MODE_WE_TRUST_THIS_DATA_ABSOLUTELY)
1028 if (!_dbus_string_validate_nul (str, padding_start, padding_len))
1030 *validity = DBUS_INVALID_ALIGNMENT_PADDING_NOT_NUL;
1035 header->padding = padding_len;
1037 if (mode == DBUS_VALIDATION_MODE_WE_TRUST_THIS_DATA_ABSOLUTELY)
1039 *validity = DBUS_VALID;
1043 /* We now know the data is well-formed, but we have to check that
1047 _dbus_type_reader_init (&reader,
1049 &_dbus_header_signature_str, 0,
1053 _dbus_assert (_dbus_type_reader_get_current_type (&reader) == DBUS_TYPE_BYTE);
1054 _dbus_assert (_dbus_type_reader_get_value_pos (&reader) == BYTE_ORDER_OFFSET);
1055 _dbus_type_reader_read_basic (&reader, &v_byte);
1056 _dbus_type_reader_next (&reader);
1058 _dbus_assert (v_byte == byte_order);
1059 header->byte_order = byte_order;
1062 _dbus_assert (_dbus_type_reader_get_current_type (&reader) == DBUS_TYPE_BYTE);
1063 _dbus_assert (_dbus_type_reader_get_value_pos (&reader) == TYPE_OFFSET);
1064 _dbus_type_reader_read_basic (&reader, &v_byte);
1065 _dbus_type_reader_next (&reader);
1067 /* unknown message types are supposed to be ignored, so only validation here is
1068 * that it isn't invalid
1070 if (v_byte == DBUS_MESSAGE_TYPE_INVALID)
1072 *validity = DBUS_INVALID_BAD_MESSAGE_TYPE;
1077 _dbus_assert (_dbus_type_reader_get_current_type (&reader) == DBUS_TYPE_BYTE);
1078 _dbus_assert (_dbus_type_reader_get_value_pos (&reader) == FLAGS_OFFSET);
1079 _dbus_type_reader_read_basic (&reader, &v_byte);
1080 _dbus_type_reader_next (&reader);
1082 /* unknown flags should be ignored */
1084 /* PROTOCOL VERSION */
1085 _dbus_assert (_dbus_type_reader_get_current_type (&reader) == DBUS_TYPE_BYTE);
1086 _dbus_assert (_dbus_type_reader_get_value_pos (&reader) == VERSION_OFFSET);
1087 _dbus_type_reader_read_basic (&reader, &v_byte);
1088 _dbus_type_reader_next (&reader);
1090 if (v_byte != DBUS_MAJOR_PROTOCOL_VERSION)
1092 *validity = DBUS_INVALID_BAD_PROTOCOL_VERSION;
1097 _dbus_assert (_dbus_type_reader_get_current_type (&reader) == DBUS_TYPE_UINT32);
1098 _dbus_assert (_dbus_type_reader_get_value_pos (&reader) == BODY_LENGTH_OFFSET);
1099 _dbus_type_reader_read_basic (&reader, &v_uint32);
1100 _dbus_type_reader_next (&reader);
1102 _dbus_assert (body_len == (signed) v_uint32);
1105 _dbus_assert (_dbus_type_reader_get_current_type (&reader) == DBUS_TYPE_UINT32);
1106 _dbus_assert (_dbus_type_reader_get_value_pos (&reader) == SERIAL_OFFSET);
1107 _dbus_type_reader_read_basic (&reader, &serial);
1108 _dbus_type_reader_next (&reader);
1112 *validity = DBUS_INVALID_BAD_SERIAL;
1116 _dbus_assert (_dbus_type_reader_get_current_type (&reader) == DBUS_TYPE_ARRAY);
1117 _dbus_assert (_dbus_type_reader_get_value_pos (&reader) == FIELDS_ARRAY_LENGTH_OFFSET);
1119 _dbus_type_reader_recurse (&reader, &array_reader);
1120 while (_dbus_type_reader_get_current_type (&array_reader) != DBUS_TYPE_INVALID)
1122 DBusTypeReader struct_reader;
1123 DBusTypeReader variant_reader;
1124 unsigned char field_code;
1126 _dbus_assert (_dbus_type_reader_get_current_type (&array_reader) == DBUS_TYPE_STRUCT);
1128 _dbus_type_reader_recurse (&array_reader, &struct_reader);
1130 _dbus_assert (_dbus_type_reader_get_current_type (&struct_reader) == DBUS_TYPE_BYTE);
1131 _dbus_type_reader_read_basic (&struct_reader, &field_code);
1132 _dbus_type_reader_next (&struct_reader);
1134 if (field_code == DBUS_HEADER_FIELD_INVALID)
1136 _dbus_verbose ("invalid header field code\n");
1137 *validity = DBUS_INVALID_HEADER_FIELD_CODE;
1141 if (field_code > DBUS_HEADER_FIELD_LAST)
1143 _dbus_verbose ("unknown header field code %d, skipping\n",
1148 _dbus_assert (_dbus_type_reader_get_current_type (&struct_reader) == DBUS_TYPE_VARIANT);
1149 _dbus_type_reader_recurse (&struct_reader, &variant_reader);
1151 v = load_and_validate_field (header, field_code, &variant_reader);
1152 if (v != DBUS_VALID)
1154 _dbus_verbose ("Field %d was invalid\n", field_code);
1160 _dbus_type_reader_next (&array_reader);
1163 /* Anything we didn't fill in is now known not to exist */
1165 while (i <= DBUS_HEADER_FIELD_LAST)
1167 if (header->fields[i].value_pos == _DBUS_HEADER_FIELD_VALUE_UNKNOWN)
1168 header->fields[i].value_pos = _DBUS_HEADER_FIELD_VALUE_NONEXISTENT;
1172 v = check_mandatory_fields (header);
1173 if (v != DBUS_VALID)
1175 _dbus_verbose ("Mandatory fields were missing, code %d\n", v);
1180 *validity = DBUS_VALID;
1184 _dbus_string_set_length (&header->data, 0);
1189 * Fills in the correct body length.
1191 * @param header the header
1192 * @param body_len the length of the body
1195 _dbus_header_update_lengths (DBusHeader *header,
1198 _dbus_marshal_set_uint32 (&header->data,
1201 header->byte_order);
1205 find_field_for_modification (DBusHeader *header,
1207 DBusTypeReader *reader,
1208 DBusTypeReader *realign_root)
1214 _dbus_type_reader_init (realign_root,
1216 &_dbus_header_signature_str,
1217 FIELDS_ARRAY_SIGNATURE_OFFSET,
1219 FIELDS_ARRAY_LENGTH_OFFSET);
1221 _dbus_type_reader_recurse (realign_root, reader);
1223 while (_dbus_type_reader_get_current_type (reader) != DBUS_TYPE_INVALID)
1226 unsigned char field_code;
1228 _dbus_type_reader_recurse (reader, &sub);
1230 _dbus_assert (_dbus_type_reader_get_current_type (&sub) == DBUS_TYPE_BYTE);
1231 _dbus_type_reader_read_basic (&sub, &field_code);
1233 if (field_code == (unsigned) field)
1235 _dbus_assert (_dbus_type_reader_get_current_type (reader) == DBUS_TYPE_STRUCT);
1240 _dbus_type_reader_next (reader);
1248 * Sets the value of a field with basic type. If the value is a string
1249 * value, it isn't allowed to be #NULL. If the field doesn't exist,
1250 * it will be created.
1252 * @param header the header
1253 * @param field the field to set
1254 * @param type the type of the value
1255 * @param value the value as for _dbus_marshal_set_basic()
1256 * @returns #FALSE if no memory
1259 _dbus_header_set_field_basic (DBusHeader *header,
1264 _dbus_assert (field <= DBUS_HEADER_FIELD_LAST);
1266 if (!reserve_header_padding (header))
1269 /* If the field exists we set, otherwise we append */
1270 if (_dbus_header_cache_check (header, field))
1272 DBusTypeReader reader;
1273 DBusTypeReader realign_root;
1275 if (!find_field_for_modification (header, field,
1276 &reader, &realign_root))
1277 _dbus_assert_not_reached ("field was marked present in cache but wasn't found");
1279 if (!set_basic_field (&reader, field, type, value, &realign_root))
1284 DBusTypeWriter writer;
1285 DBusTypeWriter array;
1287 _dbus_type_writer_init_values_only (&writer,
1289 &_dbus_header_signature_str,
1290 FIELDS_ARRAY_SIGNATURE_OFFSET,
1292 FIELDS_ARRAY_LENGTH_OFFSET);
1294 /* recurse into array without creating a new length, and jump to
1297 if (!_dbus_type_writer_append_array (&writer,
1298 &_dbus_header_signature_str,
1299 FIELDS_ARRAY_ELEMENT_SIGNATURE_OFFSET,
1301 _dbus_assert_not_reached ("recurse into ARRAY should not have used memory");
1303 _dbus_assert (array.u.array.len_pos == FIELDS_ARRAY_LENGTH_OFFSET);
1304 _dbus_assert (array.u.array.start_pos == FIRST_FIELD_OFFSET);
1305 _dbus_assert (array.value_pos == HEADER_END_BEFORE_PADDING (header));
1307 if (!write_basic_field (&array,
1308 field, type, value))
1311 if (!_dbus_type_writer_unrecurse (&writer, &array))
1312 _dbus_assert_not_reached ("unrecurse from ARRAY should not have used memory");
1315 correct_header_padding (header);
1317 /* We could be smarter about this (only invalidate fields after the
1318 * one we modified, or even only if the one we modified changed
1319 * length). But this hack is a start.
1321 _dbus_header_cache_invalidate_all (header);
1327 * Gets the value of a field with basic type. If the field
1328 * doesn't exist, returns #FALSE, otherwise returns #TRUE.
1330 * @param header the header
1331 * @param field the field to get
1332 * @param type the type of the value
1333 * @param value the value as for _dbus_marshal_read_basic()
1334 * @returns #FALSE if the field doesn't exist
1337 _dbus_header_get_field_basic (DBusHeader *header,
1342 _dbus_assert (field != DBUS_HEADER_FIELD_INVALID);
1343 _dbus_assert (field <= DBUS_HEADER_FIELD_LAST);
1344 _dbus_assert (_dbus_header_field_types[field].code == field);
1345 /* in light of this you might ask why the type is passed in;
1346 * the only rationale I can think of is so the caller has
1347 * to specify its expectation and breaks if we change it
1349 _dbus_assert (type == EXPECTED_TYPE_OF_FIELD (field));
1351 if (!_dbus_header_cache_check (header, field))
1354 _dbus_assert (header->fields[field].value_pos >= 0);
1356 _dbus_marshal_read_basic (&header->data,
1357 header->fields[field].value_pos,
1358 type, value, header->byte_order,
1365 * Gets the raw marshaled data for a field. If the field doesn't
1366 * exist, returns #FALSE, otherwise returns #TRUE. Returns the start
1367 * of the marshaled data, i.e. usually the byte where the length
1368 * starts (for strings and arrays) or for basic types just the value
1371 * @param header the header
1372 * @param field the field to get
1373 * @param str return location for the data string
1374 * @param pos return location for start of field value
1375 * @returns #FALSE if the field doesn't exist
1378 _dbus_header_get_field_raw (DBusHeader *header,
1380 const DBusString **str,
1383 if (!_dbus_header_cache_check (header, field))
1387 *str = &header->data;
1389 *pos = header->fields[field].value_pos;
1395 * Deletes a field, if it exists.
1397 * @param header the header
1398 * @param field the field to delete
1399 * @returns #FALSE if no memory
1402 _dbus_header_delete_field (DBusHeader *header,
1405 DBusTypeReader reader;
1406 DBusTypeReader realign_root;
1408 if (_dbus_header_cache_known_nonexistent (header, field))
1409 return TRUE; /* nothing to do */
1411 /* Scan to the field we want, delete and realign, reappend
1412 * padding. Field may turn out not to exist.
1414 if (!find_field_for_modification (header, field,
1415 &reader, &realign_root))
1416 return TRUE; /* nothing to do */
1418 if (!reserve_header_padding (header))
1421 if (!_dbus_type_reader_delete (&reader,
1425 correct_header_padding (header);
1427 _dbus_header_cache_invalidate_all (header);
1429 _dbus_assert (!_dbus_header_cache_check (header, field)); /* Expensive assertion ... */
1435 * Toggles a message flag bit, turning on the bit if value = TRUE and
1436 * flipping it off if value = FALSE.
1438 * @param header the header
1439 * @param flag the message flag to toggle
1440 * @param value toggle on or off
1443 _dbus_header_toggle_flag (DBusHeader *header,
1447 unsigned char *flags_p;
1449 flags_p = _dbus_string_get_data_len (&header->data, FLAGS_OFFSET, 1);
1458 * Gets a message flag bit, returning TRUE if the bit is set.
1460 * @param header the header
1461 * @param flag the message flag to get
1462 * @returns #TRUE if the flag is set
1465 _dbus_header_get_flag (DBusHeader *header,
1468 const unsigned char *flags_p;
1470 flags_p = _dbus_string_get_const_data_len (&header->data, FLAGS_OFFSET, 1);
1472 return (*flags_p & flag) != 0;
1476 * Swaps the header into the given order if required.
1478 * @param header the header
1479 * @param new_order the new byte order
1482 _dbus_header_byteswap (DBusHeader *header,
1487 byte_order = _dbus_header_get_byte_order (header);
1489 if (byte_order == new_order)
1492 _dbus_marshal_byteswap (&_dbus_header_signature_str,
1497 _dbus_string_set_byte (&header->data, BYTE_ORDER_OFFSET, new_order);
1502 #ifdef DBUS_BUILD_TESTS
1503 #include "dbus-test.h"
1507 _dbus_marshal_header_test (void)
1513 #endif /* DBUS_BUILD_TESTS */