/* -*- mode: C; c-file-style: "gnu" -*- */
/* dbus-marshal-header.c Managing marshaling/demarshaling of message headers
*
* Copyright (C) 2005 Red Hat, Inc.
*
* Licensed under the Academic Free License version 2.1
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
*/
#include "dbus/dbus-shared.h"
#include "dbus-marshal-header.h"
#include "dbus-marshal-recursive.h"
#include "dbus-marshal-byteswap.h"
/**
* @addtogroup DBusMarshal
*
* @{
*/
/* Not thread locked, but strictly const/read-only so should be OK
*/
/** Static #DBusString containing the signature of a message header */
_DBUS_STRING_DEFINE_STATIC(_dbus_header_signature_str, DBUS_HEADER_SIGNATURE);
/** Static #DBusString containing the local interface */
_DBUS_STRING_DEFINE_STATIC(_dbus_local_interface_str, DBUS_INTERFACE_LOCAL);
/** Static #DBusString containing the local path */
_DBUS_STRING_DEFINE_STATIC(_dbus_local_path_str, DBUS_PATH_LOCAL);
/** Offset from start of _dbus_header_signature_str to the signature of the fields array */
#define FIELDS_ARRAY_SIGNATURE_OFFSET 6
/** Offset from start of _dbus_header_signature_str to the signature of an element of the fields array */
#define FIELDS_ARRAY_ELEMENT_SIGNATURE_OFFSET 7
/** Offset to byte order from start of header */
#define BYTE_ORDER_OFFSET 0
/** Offset to type from start of header */
#define TYPE_OFFSET 1
/** Offset to flags from start of header */
#define FLAGS_OFFSET 2
/** Offset to version from start of header */
#define VERSION_OFFSET 3
/** Offset to body length from start of header */
#define BODY_LENGTH_OFFSET 4
/** Offset to client serial from start of header */
#define SERIAL_OFFSET 8
/** Offset to fields array length from start of header */
#define FIELDS_ARRAY_LENGTH_OFFSET 12
/** Offset to first field in header */
#define FIRST_FIELD_OFFSET 16
typedef struct
{
unsigned char code; /**< the field code */
unsigned char type; /**< the value type */
} HeaderFieldType;
static const HeaderFieldType
_dbus_header_field_types[DBUS_HEADER_FIELD_LAST+1] = {
{ DBUS_HEADER_FIELD_INVALID, DBUS_TYPE_INVALID },
{ DBUS_HEADER_FIELD_PATH, DBUS_TYPE_OBJECT_PATH },
{ DBUS_HEADER_FIELD_INTERFACE, DBUS_TYPE_STRING },
{ DBUS_HEADER_FIELD_MEMBER, DBUS_TYPE_STRING },
{ DBUS_HEADER_FIELD_ERROR_NAME, DBUS_TYPE_STRING },
{ DBUS_HEADER_FIELD_REPLY_SERIAL, DBUS_TYPE_UINT32 },
{ DBUS_HEADER_FIELD_DESTINATION, DBUS_TYPE_STRING },
{ DBUS_HEADER_FIELD_SENDER, DBUS_TYPE_STRING },
{ DBUS_HEADER_FIELD_SIGNATURE, DBUS_TYPE_SIGNATURE }
};
/** Macro to look up the correct type for a field */
#define EXPECTED_TYPE_OF_FIELD(field) (_dbus_header_field_types[field].type)
/** The most padding we could ever need for a header */
#define MAX_POSSIBLE_HEADER_PADDING 7
static dbus_bool_t
reserve_header_padding (DBusHeader *header)
{
_dbus_assert (header->padding <= MAX_POSSIBLE_HEADER_PADDING);
if (!_dbus_string_lengthen (&header->data,
MAX_POSSIBLE_HEADER_PADDING - header->padding))
return FALSE;
header->padding = MAX_POSSIBLE_HEADER_PADDING;
return TRUE;
}
static void
correct_header_padding (DBusHeader *header)
{
int unpadded_len;
_dbus_assert (header->padding == 7);
_dbus_string_shorten (&header->data, header->padding);
unpadded_len = _dbus_string_get_length (&header->data);
if (!_dbus_string_align_length (&header->data, 8))
_dbus_assert_not_reached ("couldn't pad header though enough padding was preallocated");
header->padding = _dbus_string_get_length (&header->data) - unpadded_len;
}
/** Compute the end of the header, ignoring padding */
#define HEADER_END_BEFORE_PADDING(header) \
(_dbus_string_get_length (&(header)->data) - (header)->padding)
/**
* Invalidates all fields in the cache. This may be used when the
* cache is totally uninitialized (contains junk) so should not
* look at what's in there now.
*
* @param header the header
*/
static void
_dbus_header_cache_invalidate_all (DBusHeader *header)
{
int i;
i = 0;
while (i <= DBUS_HEADER_FIELD_LAST)
{
header->fields[i].value_pos = _DBUS_HEADER_FIELD_VALUE_UNKNOWN;
++i;
}
}
/**
* Caches one field
*
* @param header the header
* @param field_code the field
* @param variant_reader the reader for the variant in the field
*/
static void
_dbus_header_cache_one (DBusHeader *header,
int field_code,
DBusTypeReader *variant_reader)
{
header->fields[field_code].value_pos =
_dbus_type_reader_get_value_pos (variant_reader);
#if 0
_dbus_verbose ("cached value_pos %d for field %d\n",
header->fields[field_code].value_pos, field_code)
#endif
}
/**
* Revalidates the fields cache
*
* @param header the header
*/
static void
_dbus_header_cache_revalidate (DBusHeader *header)
{
DBusTypeReader array;
DBusTypeReader reader;
int i;
i = 0;
while (i <= DBUS_HEADER_FIELD_LAST)
{
header->fields[i].value_pos = _DBUS_HEADER_FIELD_VALUE_NONEXISTENT;
++i;
}
_dbus_type_reader_init (&reader,
header->byte_order,
&_dbus_header_signature_str,
FIELDS_ARRAY_SIGNATURE_OFFSET,
&header->data,
FIELDS_ARRAY_LENGTH_OFFSET);
_dbus_type_reader_recurse (&reader, &array);
while (_dbus_type_reader_get_current_type (&array) != DBUS_TYPE_INVALID)
{
DBusTypeReader sub;
DBusTypeReader variant;
unsigned char field_code;
_dbus_type_reader_recurse (&array, &sub);
_dbus_assert (_dbus_type_reader_get_current_type (&sub) == DBUS_TYPE_BYTE);
_dbus_type_reader_read_basic (&sub, &field_code);
/* Unknown fields should be ignored */
if (field_code > DBUS_HEADER_FIELD_LAST)
goto next_field;
_dbus_type_reader_next (&sub);
_dbus_assert (_dbus_type_reader_get_current_type (&sub) == DBUS_TYPE_VARIANT);
_dbus_type_reader_recurse (&sub, &variant);
_dbus_header_cache_one (header, field_code, &variant);
next_field:
_dbus_type_reader_next (&array);
}
}
/**
* Checks for a field, updating the cache if required.
*
* @param header the header
* @param field the field to check
* @returns #FALSE if the field doesn't exist
*/
static dbus_bool_t
_dbus_header_cache_check (DBusHeader *header,
int field)
{
_dbus_assert (field <= DBUS_HEADER_FIELD_LAST);
if (header->fields[field].value_pos == _DBUS_HEADER_FIELD_VALUE_UNKNOWN)
_dbus_header_cache_revalidate (header);
if (header->fields[field].value_pos == _DBUS_HEADER_FIELD_VALUE_NONEXISTENT)
return FALSE;
return TRUE;
}
/**
* Checks whether a field is known not to exist. It may exist
* even if it's not known to exist.
*
* @param header the header
* @param field the field to check
* @returns #FALSE if the field definitely doesn't exist
*/
static dbus_bool_t
_dbus_header_cache_known_nonexistent (DBusHeader *header,
int field)
{
_dbus_assert (field <= DBUS_HEADER_FIELD_LAST);
return (header->fields[field].value_pos == _DBUS_HEADER_FIELD_VALUE_NONEXISTENT);
}
/**
* Writes a struct of { byte, variant } with the given basic type.
*
* @param writer the writer (should be ready to write a struct)
* @param type the type of the value
* @param value the value as for _dbus_marshal_set_basic()
* @returns #FALSE if no memory
*/
static dbus_bool_t
write_basic_field (DBusTypeWriter *writer,
int field,
int type,
const void *value)
{
DBusTypeWriter sub;
DBusTypeWriter variant;
int start;
int padding;
unsigned char field_byte;
DBusString contained_type;
char buf[2];
start = writer->value_pos;
padding = _dbus_string_get_length (writer->value_str) - start;
if (!_dbus_type_writer_recurse (writer, DBUS_TYPE_STRUCT,
NULL, 0, &sub))
goto append_failed;
field_byte = field;
if (!_dbus_type_writer_write_basic (&sub, DBUS_TYPE_BYTE,
&field_byte))
goto append_failed;
buf[0] = type;
buf[1] = '\0';
_dbus_string_init_const_len (&contained_type, buf, 1);
if (!_dbus_type_writer_recurse (&sub, DBUS_TYPE_VARIANT,
&contained_type, 0, &variant))
goto append_failed;
if (!_dbus_type_writer_write_basic (&variant, type, value))
goto append_failed;
if (!_dbus_type_writer_unrecurse (&sub, &variant))
goto append_failed;
if (!_dbus_type_writer_unrecurse (writer, &sub))
goto append_failed;
return TRUE;
append_failed:
_dbus_string_delete (writer->value_str,
start,
_dbus_string_get_length (writer->value_str) - start - padding);
return FALSE;
}
/**
* Sets a struct of { byte, variant } with the given basic type.
*
* @param reader the reader (should be iterating over the array pointing at the field to set)
* @param type the type of the value
* @param value the value as for _dbus_marshal_set_basic()
* @param realign_root where to realign from
* @returns #FALSE if no memory
*/
static dbus_bool_t
set_basic_field (DBusTypeReader *reader,
int field,
int type,
const void *value,
const DBusTypeReader *realign_root)
{
DBusTypeReader sub;
DBusTypeReader variant;
_dbus_type_reader_recurse (reader, &sub);
_dbus_assert (_dbus_type_reader_get_current_type (&sub) == DBUS_TYPE_BYTE);
#ifndef DBUS_DISABLE_ASSERT
{
unsigned char v_BYTE;
_dbus_type_reader_read_basic (&sub, &v_BYTE);
_dbus_assert (((int) v_BYTE) == field);
}
#endif
if (!_dbus_type_reader_next (&sub))
_dbus_assert_not_reached ("no variant field?");
_dbus_type_reader_recurse (&sub, &variant);
_dbus_assert (_dbus_type_reader_get_current_type (&variant) == type);
if (!_dbus_type_reader_set_basic (&variant, value, realign_root))
return FALSE;
return TRUE;
}
/**
* Gets the type of the message.
*
* @param header the header
* @returns the type
*/
int
_dbus_header_get_message_type (DBusHeader *header)
{
int type;
type = _dbus_string_get_byte (&header->data, TYPE_OFFSET);
_dbus_assert (type != DBUS_MESSAGE_TYPE_INVALID);
return type;
}
/**
* Sets the serial number of a header. This can only be done once on
* a header.
*
* @param header the header
* @param serial the serial
*/
void
_dbus_header_set_serial (DBusHeader *header,
dbus_uint32_t serial)
{
/* we use this function to set the serial on outgoing
* messages, and to reset the serial in dbus_message_copy;
* this assertion should catch a double-set on outgoing.
*/
_dbus_assert (_dbus_header_get_serial (header) == 0 ||
serial == 0);
_dbus_marshal_set_uint32 (&header->data,
SERIAL_OFFSET,
serial,
header->byte_order);
}
/**
* See dbus_message_get_serial()
*
* @param header the header
* @returns the client serial
*/
dbus_uint32_t
_dbus_header_get_serial (DBusHeader *header)
{
return _dbus_marshal_read_uint32 (&header->data,
SERIAL_OFFSET,
header->byte_order,
NULL);
}
/**
* Re-initializes a header that was previously initialized and never
* freed. After this, to make the header valid you have to call
* _dbus_header_create().
*
* @param header header to re-initialize
* @param byte_order byte order of the header
*/
void
_dbus_header_reinit (DBusHeader *header,
int byte_order)
{
_dbus_string_set_length (&header->data, 0);
header->byte_order = byte_order;
header->padding = 0;
_dbus_header_cache_invalidate_all (header);
}
/**
* Initializes a header, but doesn't prepare it for use;
* to make the header valid, you have to call _dbus_header_create().
*
* @param header header to initialize
* @param byte_order byte order of the header
* @returns #FALSE if not enough memory
*/
dbus_bool_t
_dbus_header_init (DBusHeader *header,
int byte_order)
{
if (!_dbus_string_init_preallocated (&header->data, 32))
return FALSE;
_dbus_header_reinit (header, byte_order);
return TRUE;
}
/**
* Frees a header.
*
* @param header the header
*/
void
_dbus_header_free (DBusHeader *header)
{
_dbus_string_free (&header->data);
}
/**
* Initializes dest with a copy of the given header.
* Resets the message serial to 0 on the copy.
*
* @param header header to copy
* @param dest destination for copy
* @returns #FALSE if not enough memory
*/
dbus_bool_t
_dbus_header_copy (const DBusHeader *header,
DBusHeader *dest)
{
*dest = *header;
if (!_dbus_string_init_preallocated (&dest->data,
_dbus_string_get_length (&header->data)))
return FALSE;
if (!_dbus_string_copy (&header->data, 0, &dest->data, 0))
{
_dbus_string_free (&dest->data);
return FALSE;
}
/* Reset the serial */
_dbus_header_set_serial (dest, 0);
return TRUE;
}
/**
* Fills in the primary fields of the header, so the header is ready
* for use. #NULL may be specified for some or all of the fields to
* avoid adding those fields. Some combinations of fields don't make
* sense, and passing them in will trigger an assertion failure.
*
* @param header the header
* @param message_type the message type
* @param destination destination field or #NULL
* @param path path field or #NULL
* @param interface interface field or #NULL
* @param member member field or #NULL
* @param error_name error name or #NULL
* @returns #FALSE if not enough memory
*/
dbus_bool_t
_dbus_header_create (DBusHeader *header,
int message_type,
const char *destination,
const char *path,
const char *interface,
const char *member,
const char *error_name)
{
unsigned char v_BYTE;
dbus_uint32_t v_UINT32;
DBusTypeWriter writer;
DBusTypeWriter array;
_dbus_assert (((interface || message_type != DBUS_MESSAGE_TYPE_SIGNAL) && member) ||
(error_name) ||
!(interface || member || error_name));
_dbus_assert (_dbus_string_get_length (&header->data) == 0);
if (!reserve_header_padding (header))
return FALSE;
_dbus_type_writer_init_values_only (&writer, header->byte_order,
&_dbus_header_signature_str, 0,
&header->data,
HEADER_END_BEFORE_PADDING (header));
v_BYTE = header->byte_order;
if (!_dbus_type_writer_write_basic (&writer, DBUS_TYPE_BYTE,
&v_BYTE))
goto oom;
v_BYTE = message_type;
if (!_dbus_type_writer_write_basic (&writer, DBUS_TYPE_BYTE,
&v_BYTE))
goto oom;
v_BYTE = 0; /* flags */
if (!_dbus_type_writer_write_basic (&writer, DBUS_TYPE_BYTE,
&v_BYTE))
goto oom;
v_BYTE = DBUS_MAJOR_PROTOCOL_VERSION;
if (!_dbus_type_writer_write_basic (&writer, DBUS_TYPE_BYTE,
&v_BYTE))
goto oom;
v_UINT32 = 0; /* body length */
if (!_dbus_type_writer_write_basic (&writer, DBUS_TYPE_UINT32,
&v_UINT32))
goto oom;
v_UINT32 = 0; /* serial */
if (!_dbus_type_writer_write_basic (&writer, DBUS_TYPE_UINT32,
&v_UINT32))
goto oom;
if (!_dbus_type_writer_recurse (&writer, DBUS_TYPE_ARRAY,
&_dbus_header_signature_str,
FIELDS_ARRAY_SIGNATURE_OFFSET,
&array))
goto oom;
/* Marshal all the fields (Marshall Fields?) */
if (path != NULL)
{
if (!write_basic_field (&array,
DBUS_HEADER_FIELD_PATH,
DBUS_TYPE_OBJECT_PATH,
&path))
goto oom;
}
if (destination != NULL)
{
if (!write_basic_field (&array,
DBUS_HEADER_FIELD_DESTINATION,
DBUS_TYPE_STRING,
&destination))
goto oom;
}
if (interface != NULL)
{
if (!write_basic_field (&array,
DBUS_HEADER_FIELD_INTERFACE,
DBUS_TYPE_STRING,
&interface))
goto oom;
}
if (member != NULL)
{
if (!write_basic_field (&array,
DBUS_HEADER_FIELD_MEMBER,
DBUS_TYPE_STRING,
&member))
goto oom;
}
if (error_name != NULL)
{
if (!write_basic_field (&array,
DBUS_HEADER_FIELD_ERROR_NAME,
DBUS_TYPE_STRING,
&error_name))
goto oom;
}
if (!_dbus_type_writer_unrecurse (&writer, &array))
goto oom;
correct_header_padding (header);
return TRUE;
oom:
_dbus_string_delete (&header->data, 0,
_dbus_string_get_length (&header->data) - header->padding);
correct_header_padding (header);
return FALSE;
}
/**
* Given data long enough to contain the length of the message body
* and the fields array, check whether the data is long enough to
* contain the entire message (assuming the claimed lengths are
* accurate). Also checks that the lengths are in sanity parameters.
*
* @param max_message_length maximum length of a valid message
* @param validity return location for why the data is invalid if it is
* @param byte_order return location for byte order
* @param fields_array_len return location for claimed fields array length
* @param header_len return location for claimed header length
* @param body_len return location for claimed body length
* @param str the data
* @param start start of data, 8-aligned
* @param len length of data
* @returns #TRUE if the data is long enough for the claimed length, and the lengths were valid
*/
dbus_bool_t
_dbus_header_have_message_untrusted (int max_message_length,
DBusValidity *validity,
int *byte_order,
int *fields_array_len,
int *header_len,
int *body_len,
const DBusString *str,
int start,
int len)
{
dbus_uint32_t header_len_unsigned;
dbus_uint32_t fields_array_len_unsigned;
dbus_uint32_t body_len_unsigned;
_dbus_assert (start >= 0);
_dbus_assert (start < _DBUS_INT32_MAX / 2);
_dbus_assert (len >= 0);
_dbus_assert (start == (int) _DBUS_ALIGN_VALUE (start, 8));
*byte_order = _dbus_string_get_byte (str, start + BYTE_ORDER_OFFSET);
if (*byte_order != DBUS_LITTLE_ENDIAN && *byte_order != DBUS_BIG_ENDIAN)
{
*validity = DBUS_INVALID_BAD_BYTE_ORDER;
return FALSE;
}
_dbus_assert (FIELDS_ARRAY_LENGTH_OFFSET + 4 <= len);
fields_array_len_unsigned = _dbus_marshal_read_uint32 (str, start + FIELDS_ARRAY_LENGTH_OFFSET,
*byte_order, NULL);
if (fields_array_len_unsigned > (unsigned) max_message_length)
{
*validity = DBUS_INVALID_INSANE_FIELDS_ARRAY_LENGTH;
return FALSE;
}
_dbus_assert (BODY_LENGTH_OFFSET + 4 < len);
body_len_unsigned = _dbus_marshal_read_uint32 (str, start + BODY_LENGTH_OFFSET,
*byte_order, NULL);
if (body_len_unsigned > (unsigned) max_message_length)
{
*validity = DBUS_INVALID_INSANE_BODY_LENGTH;
return FALSE;
}
header_len_unsigned = FIRST_FIELD_OFFSET + fields_array_len_unsigned;
header_len_unsigned = _DBUS_ALIGN_VALUE (header_len_unsigned, 8);
/* overflow should be impossible since the lengths aren't allowed to
* be huge.
*/
_dbus_assert (max_message_length < _DBUS_INT32_MAX / 2);
if (body_len_unsigned + header_len_unsigned > (unsigned) max_message_length)
{
*validity = DBUS_INVALID_MESSAGE_TOO_LONG;
return FALSE;
}
_dbus_assert (body_len_unsigned < (unsigned) _DBUS_INT32_MAX);
_dbus_assert (fields_array_len_unsigned < (unsigned) _DBUS_INT32_MAX);
_dbus_assert (header_len_unsigned < (unsigned) _DBUS_INT32_MAX);
*body_len = body_len_unsigned;
*fields_array_len = fields_array_len_unsigned;
*header_len = header_len_unsigned;
*validity = DBUS_VALID;
_dbus_verbose ("have %d bytes, need body %u + header %u = %u\n",
len, body_len_unsigned, header_len_unsigned,
body_len_unsigned + header_len_unsigned);
return (body_len_unsigned + header_len_unsigned) <= (unsigned) len;
}
static DBusValidity
check_mandatory_fields (DBusHeader *header)
{
#define REQUIRE_FIELD(name) do { if (header->fields[DBUS_HEADER_FIELD_##name].value_pos < 0) return DBUS_INVALID_MISSING_##name; } while (0)
switch (_dbus_header_get_message_type (header))
{
case DBUS_MESSAGE_TYPE_SIGNAL:
REQUIRE_FIELD (INTERFACE);
/* FALL THRU - signals also require the path and member */
case DBUS_MESSAGE_TYPE_METHOD_CALL:
REQUIRE_FIELD (PATH);
REQUIRE_FIELD (MEMBER);
break;
case DBUS_MESSAGE_TYPE_ERROR:
REQUIRE_FIELD (ERROR_NAME);
REQUIRE_FIELD (REPLY_SERIAL);
break;
case DBUS_MESSAGE_TYPE_METHOD_RETURN:
REQUIRE_FIELD (REPLY_SERIAL);
break;
default:
/* other message types allowed but ignored */
break;
}
return DBUS_VALID;
}
static DBusValidity
load_and_validate_field (DBusHeader *header,
int field,
DBusTypeReader *variant_reader)
{
int type;
int expected_type;
const DBusString *value_str;
int value_pos;
int str_data_pos;
dbus_uint32_t v_UINT32;
int bad_string_code;
dbus_bool_t (* string_validation_func) (const DBusString *str,
int start, int len);
/* Supposed to have been checked already */
_dbus_assert (field <= DBUS_HEADER_FIELD_LAST);
_dbus_assert (field != DBUS_HEADER_FIELD_INVALID);
/* Before we can cache a field, we need to know it has the right type */
type = _dbus_type_reader_get_current_type (variant_reader);
_dbus_assert (_dbus_header_field_types[field].code == field);
expected_type = EXPECTED_TYPE_OF_FIELD (field);
if (type != expected_type)
{
_dbus_verbose ("Field %d should have type %d but has %d\n",
field, expected_type, type);
return DBUS_INVALID_HEADER_FIELD_HAS_WRONG_TYPE;
}
/* If the field was provided twice, we aren't happy */
if (header->fields[field].value_pos >= 0)
{
_dbus_verbose ("Header field %d seen a second time\n", field);
return DBUS_INVALID_HEADER_FIELD_APPEARS_TWICE;
}
/* Now we can cache and look at the field content */
_dbus_verbose ("initially caching field %d\n", field);
_dbus_header_cache_one (header, field, variant_reader);
string_validation_func = NULL;
/* make compiler happy that all this is initialized */
v_UINT32 = 0;
value_str = NULL;
value_pos = -1;
str_data_pos = -1;
bad_string_code = DBUS_VALID;
if (expected_type == DBUS_TYPE_UINT32)
{
_dbus_header_get_field_basic (header, field, expected_type,
&v_UINT32);
}
else if (expected_type == DBUS_TYPE_STRING ||
expected_type == DBUS_TYPE_OBJECT_PATH ||
expected_type == DBUS_TYPE_SIGNATURE)
{
_dbus_header_get_field_raw (header, field,
&value_str, &value_pos);
str_data_pos = _DBUS_ALIGN_VALUE (value_pos, 4) + 4;
}
else
{
_dbus_assert_not_reached ("none of the known fields should have this type");
}
switch (field)
{
case DBUS_HEADER_FIELD_DESTINATION:
string_validation_func = _dbus_validate_bus_name;
bad_string_code = DBUS_INVALID_BAD_DESTINATION;
break;
case DBUS_HEADER_FIELD_INTERFACE:
string_validation_func = _dbus_validate_interface;
bad_string_code = DBUS_INVALID_BAD_INTERFACE;
if (_dbus_string_equal_substring (&_dbus_local_interface_str,
0,
_dbus_string_get_length (&_dbus_local_interface_str),
value_str, str_data_pos))
{
_dbus_verbose ("Message is on the local interface\n");
return DBUS_INVALID_USES_LOCAL_INTERFACE;
}
break;
case DBUS_HEADER_FIELD_MEMBER:
string_validation_func = _dbus_validate_member;
bad_string_code = DBUS_INVALID_BAD_MEMBER;
break;
case DBUS_HEADER_FIELD_ERROR_NAME:
string_validation_func = _dbus_validate_error_name;
bad_string_code = DBUS_INVALID_BAD_ERROR_NAME;
break;
case DBUS_HEADER_FIELD_SENDER:
string_validation_func = _dbus_validate_bus_name;
bad_string_code = DBUS_INVALID_BAD_SENDER;
break;
case DBUS_HEADER_FIELD_PATH:
/* OBJECT_PATH was validated generically due to its type */
string_validation_func = NULL;
if (_dbus_string_equal_substring (&_dbus_local_path_str,
0,
_dbus_string_get_length (&_dbus_local_path_str),
value_str, str_data_pos))
{
_dbus_verbose ("Message is from the local path\n");
return DBUS_INVALID_USES_LOCAL_PATH;
}
break;
case DBUS_HEADER_FIELD_REPLY_SERIAL:
/* Can't be 0 */
if (v_UINT32 == 0)
{
return DBUS_INVALID_BAD_SERIAL;
}
break;
case DBUS_HEADER_FIELD_SIGNATURE:
/* SIGNATURE validated generically due to its type */
string_validation_func = NULL;
break;
default:
_dbus_assert_not_reached ("unknown field shouldn't be seen here");
break;
}
if (string_validation_func)
{
dbus_uint32_t len;
_dbus_assert (bad_string_code != DBUS_VALID);
len = _dbus_marshal_read_uint32 (value_str, value_pos,
header->byte_order, NULL);
#if 0
_dbus_verbose ("Validating string header field; code %d if fails\n",
bad_string_code);
#endif
if (!(*string_validation_func) (value_str, str_data_pos, len))
return bad_string_code;
}
return DBUS_VALID;
}
/**
* Creates a message header from potentially-untrusted data. The
* return value is #TRUE if there was enough memory and the data was
* valid. If it returns #TRUE, the header will be created. If it
* returns #FALSE and *validity == #DBUS_VALIDITY_UNKNOWN_OOM_ERROR,
* then there wasn't enough memory. If it returns #FALSE
* and *validity != #DBUS_VALIDITY_UNKNOWN_OOM_ERROR then the data was
* invalid.
*
* The byte_order, fields_array_len, and body_len args should be from
* _dbus_header_have_message_untrusted(). Validation performed in
* _dbus_header_have_message_untrusted() is assumed to have been
* already done.
*
* @param header the header (must be initialized)
* @param mode whether to do validation
* @param validity return location for invalidity reason
* @param byte_order byte order from header
* @param fields_array_len claimed length of fields array
* @param body_len claimed length of body
* @param header_len claimed length of header
* @param str a string
* @param start start of header, 8-aligned
* @param len length of string to look at
* @returns #FALSE if no memory or data was invalid, #TRUE otherwise
*/
dbus_bool_t
_dbus_header_load (DBusHeader *header,
DBusValidationMode mode,
DBusValidity *validity,
int byte_order,
int fields_array_len,
int header_len,
int body_len,
const DBusString *str,
int start,
int len)
{
int leftover;
DBusValidity v;
DBusTypeReader reader;
DBusTypeReader array_reader;
unsigned char v_byte;
dbus_uint32_t v_uint32;
dbus_uint32_t serial;
int padding_start;
int padding_len;
int i;
_dbus_assert (start == (int) _DBUS_ALIGN_VALUE (start, 8));
_dbus_assert (header_len <= len);
_dbus_assert (_dbus_string_get_length (&header->data) == 0);
if (!_dbus_string_copy_len (str, start, header_len, &header->data, 0))
{
_dbus_verbose ("Failed to copy buffer into new header\n");
*validity = DBUS_VALIDITY_UNKNOWN_OOM_ERROR;
return FALSE;
}
if (mode == DBUS_VALIDATION_MODE_WE_TRUST_THIS_DATA_ABSOLUTELY)
{
leftover = len - header_len - body_len - start;
}
else
{
v = _dbus_validate_body_with_reason (&_dbus_header_signature_str, 0,
byte_order,
&leftover,
str, start, len);
if (v != DBUS_VALID)
{
*validity = v;
goto invalid;
}
}
_dbus_assert (leftover < len);
padding_len = header_len - (FIRST_FIELD_OFFSET + fields_array_len);
padding_start = start + FIRST_FIELD_OFFSET + fields_array_len;
_dbus_assert (start + header_len == (int) _DBUS_ALIGN_VALUE (padding_start, 8));
_dbus_assert (start + header_len == padding_start + padding_len);
if (mode != DBUS_VALIDATION_MODE_WE_TRUST_THIS_DATA_ABSOLUTELY)
{
if (!_dbus_string_validate_nul (str, padding_start, padding_len))
{
*validity = DBUS_INVALID_ALIGNMENT_PADDING_NOT_NUL;
goto invalid;
}
}
header->padding = padding_len;
if (mode == DBUS_VALIDATION_MODE_WE_TRUST_THIS_DATA_ABSOLUTELY)
{
*validity = DBUS_VALID;
return TRUE;
}
/* We now know the data is well-formed, but we have to check that
* it's valid.
*/
_dbus_type_reader_init (&reader,
byte_order,
&_dbus_header_signature_str, 0,
str, start);
/* BYTE ORDER */
_dbus_assert (_dbus_type_reader_get_current_type (&reader) == DBUS_TYPE_BYTE);
_dbus_assert (_dbus_type_reader_get_value_pos (&reader) == BYTE_ORDER_OFFSET);
_dbus_type_reader_read_basic (&reader, &v_byte);
_dbus_type_reader_next (&reader);
_dbus_assert (v_byte == byte_order);
header->byte_order = byte_order;
/* MESSAGE TYPE */
_dbus_assert (_dbus_type_reader_get_current_type (&reader) == DBUS_TYPE_BYTE);
_dbus_assert (_dbus_type_reader_get_value_pos (&reader) == TYPE_OFFSET);
_dbus_type_reader_read_basic (&reader, &v_byte);
_dbus_type_reader_next (&reader);
/* unknown message types are supposed to be ignored, so only validation here is
* that it isn't invalid
*/
if (v_byte == DBUS_MESSAGE_TYPE_INVALID)
{
*validity = DBUS_INVALID_BAD_MESSAGE_TYPE;
goto invalid;
}
/* FLAGS */
_dbus_assert (_dbus_type_reader_get_current_type (&reader) == DBUS_TYPE_BYTE);
_dbus_assert (_dbus_type_reader_get_value_pos (&reader) == FLAGS_OFFSET);
_dbus_type_reader_read_basic (&reader, &v_byte);
_dbus_type_reader_next (&reader);
/* unknown flags should be ignored */
/* PROTOCOL VERSION */
_dbus_assert (_dbus_type_reader_get_current_type (&reader) == DBUS_TYPE_BYTE);
_dbus_assert (_dbus_type_reader_get_value_pos (&reader) == VERSION_OFFSET);
_dbus_type_reader_read_basic (&reader, &v_byte);
_dbus_type_reader_next (&reader);
if (v_byte != DBUS_MAJOR_PROTOCOL_VERSION)
{
*validity = DBUS_INVALID_BAD_PROTOCOL_VERSION;
goto invalid;
}
/* BODY LENGTH */
_dbus_assert (_dbus_type_reader_get_current_type (&reader) == DBUS_TYPE_UINT32);
_dbus_assert (_dbus_type_reader_get_value_pos (&reader) == BODY_LENGTH_OFFSET);
_dbus_type_reader_read_basic (&reader, &v_uint32);
_dbus_type_reader_next (&reader);
_dbus_assert (body_len == (signed) v_uint32);
/* SERIAL */
_dbus_assert (_dbus_type_reader_get_current_type (&reader) == DBUS_TYPE_UINT32);
_dbus_assert (_dbus_type_reader_get_value_pos (&reader) == SERIAL_OFFSET);
_dbus_type_reader_read_basic (&reader, &serial);
_dbus_type_reader_next (&reader);
if (serial == 0)
{
*validity = DBUS_INVALID_BAD_SERIAL;
goto invalid;
}
_dbus_assert (_dbus_type_reader_get_current_type (&reader) == DBUS_TYPE_ARRAY);
_dbus_assert (_dbus_type_reader_get_value_pos (&reader) == FIELDS_ARRAY_LENGTH_OFFSET);
_dbus_type_reader_recurse (&reader, &array_reader);
while (_dbus_type_reader_get_current_type (&array_reader) != DBUS_TYPE_INVALID)
{
DBusTypeReader struct_reader;
DBusTypeReader variant_reader;
unsigned char field_code;
_dbus_assert (_dbus_type_reader_get_current_type (&array_reader) == DBUS_TYPE_STRUCT);
_dbus_type_reader_recurse (&array_reader, &struct_reader);
_dbus_assert (_dbus_type_reader_get_current_type (&struct_reader) == DBUS_TYPE_BYTE);
_dbus_type_reader_read_basic (&struct_reader, &field_code);
_dbus_type_reader_next (&struct_reader);
if (field_code == DBUS_HEADER_FIELD_INVALID)
{
_dbus_verbose ("invalid header field code\n");
*validity = DBUS_INVALID_HEADER_FIELD_CODE;
goto invalid;
}
if (field_code > DBUS_HEADER_FIELD_LAST)
{
_dbus_verbose ("unknown header field code %d, skipping\n",
field_code);
goto next_field;
}
_dbus_assert (_dbus_type_reader_get_current_type (&struct_reader) == DBUS_TYPE_VARIANT);
_dbus_type_reader_recurse (&struct_reader, &variant_reader);
v = load_and_validate_field (header, field_code, &variant_reader);
if (v != DBUS_VALID)
{
_dbus_verbose ("Field %d was invalid\n", field_code);
*validity = v;
goto invalid;
}
next_field:
_dbus_type_reader_next (&array_reader);
}
/* Anything we didn't fill in is now known not to exist */
i = 0;
while (i <= DBUS_HEADER_FIELD_LAST)
{
if (header->fields[i].value_pos == _DBUS_HEADER_FIELD_VALUE_UNKNOWN)
header->fields[i].value_pos = _DBUS_HEADER_FIELD_VALUE_NONEXISTENT;
++i;
}
v = check_mandatory_fields (header);
if (v != DBUS_VALID)
{
_dbus_verbose ("Mandatory fields were missing, code %d\n", v);
*validity = v;
goto invalid;
}
*validity = DBUS_VALID;
return TRUE;
invalid:
_dbus_string_set_length (&header->data, 0);
return FALSE;
}
/**
* Fills in the correct body length.
*
* @param header the header
* @param body_len the length of the body
*/
void
_dbus_header_update_lengths (DBusHeader *header,
int body_len)
{
_dbus_marshal_set_uint32 (&header->data,
BODY_LENGTH_OFFSET,
body_len,
header->byte_order);
}
static dbus_bool_t
find_field_for_modification (DBusHeader *header,
int field,
DBusTypeReader *reader,
DBusTypeReader *realign_root)
{
dbus_bool_t retval;
retval = FALSE;
_dbus_type_reader_init (realign_root,
header->byte_order,
&_dbus_header_signature_str,
FIELDS_ARRAY_SIGNATURE_OFFSET,
&header->data,
FIELDS_ARRAY_LENGTH_OFFSET);
_dbus_type_reader_recurse (realign_root, reader);
while (_dbus_type_reader_get_current_type (reader) != DBUS_TYPE_INVALID)
{
DBusTypeReader sub;
unsigned char field_code;
_dbus_type_reader_recurse (reader, &sub);
_dbus_assert (_dbus_type_reader_get_current_type (&sub) == DBUS_TYPE_BYTE);
_dbus_type_reader_read_basic (&sub, &field_code);
if (field_code == (unsigned) field)
{
_dbus_assert (_dbus_type_reader_get_current_type (reader) == DBUS_TYPE_STRUCT);
retval = TRUE;
goto done;
}
_dbus_type_reader_next (reader);
}
done:
return retval;
}
/**
* Sets the value of a field with basic type. If the value is a string
* value, it isn't allowed to be #NULL. If the field doesn't exist,
* it will be created.
*
* @param header the header
* @param field the field to set
* @param type the type of the value
* @param value the value as for _dbus_marshal_set_basic()
* @returns #FALSE if no memory
*/
dbus_bool_t
_dbus_header_set_field_basic (DBusHeader *header,
int field,
int type,
const void *value)
{
_dbus_assert (field <= DBUS_HEADER_FIELD_LAST);
if (!reserve_header_padding (header))
return FALSE;
/* If the field exists we set, otherwise we append */
if (_dbus_header_cache_check (header, field))
{
DBusTypeReader reader;
DBusTypeReader realign_root;
if (!find_field_for_modification (header, field,
&reader, &realign_root))
_dbus_assert_not_reached ("field was marked present in cache but wasn't found");
if (!set_basic_field (&reader, field, type, value, &realign_root))
return FALSE;
}
else
{
DBusTypeWriter writer;
DBusTypeWriter array;
_dbus_type_writer_init_values_only (&writer,
header->byte_order,
&_dbus_header_signature_str,
FIELDS_ARRAY_SIGNATURE_OFFSET,
&header->data,
FIELDS_ARRAY_LENGTH_OFFSET);
/* recurse into array without creating a new length, and jump to
* end of array.
*/
if (!_dbus_type_writer_append_array (&writer,
&_dbus_header_signature_str,
FIELDS_ARRAY_ELEMENT_SIGNATURE_OFFSET,
&array))
_dbus_assert_not_reached ("recurse into ARRAY should not have used memory");
_dbus_assert (array.u.array.len_pos == FIELDS_ARRAY_LENGTH_OFFSET);
_dbus_assert (array.u.array.start_pos == FIRST_FIELD_OFFSET);
_dbus_assert (array.value_pos == HEADER_END_BEFORE_PADDING (header));
if (!write_basic_field (&array,
field, type, value))
return FALSE;
if (!_dbus_type_writer_unrecurse (&writer, &array))
_dbus_assert_not_reached ("unrecurse from ARRAY should not have used memory");
}
correct_header_padding (header);
/* We could be smarter about this (only invalidate fields after the
* one we modified, or even only if the one we modified changed
* length). But this hack is a start.
*/
_dbus_header_cache_invalidate_all (header);
return TRUE;
}
/**
* Gets the value of a field with basic type. If the field
* doesn't exist, returns #FALSE, otherwise returns #TRUE.
*
* @param header the header
* @param field the field to get
* @param type the type of the value
* @param value the value as for _dbus_marshal_read_basic()
* @returns #FALSE if the field doesn't exist
*/
dbus_bool_t
_dbus_header_get_field_basic (DBusHeader *header,
int field,
int type,
void *value)
{
_dbus_assert (field != DBUS_HEADER_FIELD_INVALID);
_dbus_assert (field <= DBUS_HEADER_FIELD_LAST);
_dbus_assert (_dbus_header_field_types[field].code == field);
/* in light of this you might ask why the type is passed in;
* the only rationale I can think of is so the caller has
* to specify its expectation and breaks if we change it
*/
_dbus_assert (type == EXPECTED_TYPE_OF_FIELD (field));
if (!_dbus_header_cache_check (header, field))
return FALSE;
_dbus_assert (header->fields[field].value_pos >= 0);
_dbus_marshal_read_basic (&header->data,
header->fields[field].value_pos,
type, value, header->byte_order,
NULL);
return TRUE;
}
/**
* Gets the raw marshaled data for a field. If the field doesn't
* exist, returns #FALSE, otherwise returns #TRUE. Returns the start
* of the marshaled data, i.e. usually the byte where the length
* starts (for strings and arrays) or for basic types just the value
* itself.
*
* @param header the header
* @param field the field to get
* @param str return location for the data string
* @param pos return location for start of field value
* @returns #FALSE if the field doesn't exist
*/
dbus_bool_t
_dbus_header_get_field_raw (DBusHeader *header,
int field,
const DBusString **str,
int *pos)
{
if (!_dbus_header_cache_check (header, field))
return FALSE;
if (str)
*str = &header->data;
if (pos)
*pos = header->fields[field].value_pos;
return TRUE;
}
/**
* Deletes a field, if it exists.
*
* @param header the header
* @param field the field to delete
* @returns #FALSE if no memory
*/
dbus_bool_t
_dbus_header_delete_field (DBusHeader *header,
int field)
{
DBusTypeReader reader;
DBusTypeReader realign_root;
if (_dbus_header_cache_known_nonexistent (header, field))
return TRUE; /* nothing to do */
/* Scan to the field we want, delete and realign, reappend
* padding. Field may turn out not to exist.
*/
if (!find_field_for_modification (header, field,
&reader, &realign_root))
return TRUE; /* nothing to do */
if (!reserve_header_padding (header))
return FALSE;
if (!_dbus_type_reader_delete (&reader,
&realign_root))
return FALSE;
correct_header_padding (header);
_dbus_header_cache_invalidate_all (header);
_dbus_assert (!_dbus_header_cache_check (header, field)); /* Expensive assertion ... */
return TRUE;
}
/**
* Toggles a message flag bit, turning on the bit if value = TRUE and
* flipping it off if value = FALSE.
*
* @param header the header
* @param flag the message flag to toggle
* @param value toggle on or off
*/
void
_dbus_header_toggle_flag (DBusHeader *header,
dbus_uint32_t flag,
dbus_bool_t value)
{
unsigned char *flags_p;
flags_p = _dbus_string_get_data_len (&header->data, FLAGS_OFFSET, 1);
if (value)
*flags_p |= flag;
else
*flags_p &= ~flag;
}
/**
* Gets a message flag bit, returning TRUE if the bit is set.
*
* @param header the header
* @param flag the message flag to get
* @returns #TRUE if the flag is set
*/
dbus_bool_t
_dbus_header_get_flag (DBusHeader *header,
dbus_uint32_t flag)
{
const unsigned char *flags_p;
flags_p = _dbus_string_get_const_data_len (&header->data, FLAGS_OFFSET, 1);
return (*flags_p & flag) != 0;
}
/**
* Swaps the header into the given order if required.
*
* @param header the header
* @param new_order the new byte order
*/
void
_dbus_header_byteswap (DBusHeader *header,
int new_order)
{
if (header->byte_order == new_order)
return;
_dbus_marshal_byteswap (&_dbus_header_signature_str,
0, header->byte_order,
new_order,
&header->data, 0);
header->byte_order = new_order;
}
/** @} */
#ifdef DBUS_BUILD_TESTS
#include "dbus-test.h"
#include <stdio.h>
dbus_bool_t
_dbus_marshal_header_test (void)
{
return TRUE;
}
#endif /* DBUS_BUILD_TESTS */