/**
* Checks that the given range of the string is a valid message type
* signature in the D-Bus protocol.
*
* @todo this is inconsistent with most of DBusString in that
* it allows a start,len range that extends past the string end.
*
* @param str the string
* @param start first byte index to check
* @param len number of bytes to check
* @returns #TRUE if the byte range exists and is a valid signature
*/
dbus_bool_t
_dbus_validate_signature (const DBusString *str,
int start,
int len)
{
_dbus_assert (start >= 0);
_dbus_assert (start <= _dbus_string_get_length (str));
_dbus_assert (len >= 0);
if (len > _dbus_string_get_length (str) - start)
return FALSE;
return _dbus_validate_signature_with_reason (str, start, len) == DBUS_VALID;
}
/**
* Check a type signature for validity. Remember that #NULL can always
* be passed instead of a DBusError*, if you don't care about having
* an error name and message.
*
* @param signature a potentially invalid type signature
* @param error error return
* @returns #TRUE if signature is valid or #FALSE if an error is set
*/
dbus_bool_t
dbus_signature_validate (const char *signature,
DBusError *error)
{
DBusString str;
DBusValidity reason;
_dbus_string_init_const (&str, signature);
reason = _dbus_validate_signature_with_reason (&str, 0, _dbus_string_get_length (&str));
if (reason == DBUS_VALID)
return TRUE;
else
{
dbus_set_error (error, DBUS_ERROR_INVALID_SIGNATURE, _dbus_validity_to_error_message (reason));
return FALSE;
}
}
static DBusValidity
validate_body_helper (DBusTypeReader *reader,
int byte_order,
dbus_bool_t walk_reader_to_end,
const unsigned char *p,
const unsigned char *end,
const unsigned char **new_p)
{
int current_type;
while ((current_type = _dbus_type_reader_get_current_type (reader)) != DBUS_TYPE_INVALID)
{
const unsigned char *a;
int alignment;
#if 0
_dbus_verbose (" validating value of type %s type reader %p type_pos %d p %p end %p %d remain\n",
_dbus_type_to_string (current_type), reader, reader->type_pos, p, end,
(int) (end - p));
#endif
/* Guarantee that p has one byte to look at */
if (p == end)
return DBUS_INVALID_NOT_ENOUGH_DATA;
switch (current_type)
{
case DBUS_TYPE_BYTE:
++p;
break;
case DBUS_TYPE_BOOLEAN:
case DBUS_TYPE_INT16:
case DBUS_TYPE_UINT16:
case DBUS_TYPE_INT32:
case DBUS_TYPE_UINT32:
case DBUS_TYPE_INT64:
case DBUS_TYPE_UINT64:
case DBUS_TYPE_DOUBLE:
alignment = _dbus_type_get_alignment (current_type);
a = _DBUS_ALIGN_ADDRESS (p, alignment);
if (a >= end)
return DBUS_INVALID_NOT_ENOUGH_DATA;
while (p != a)
{
if (*p != '\0')
return DBUS_INVALID_ALIGNMENT_PADDING_NOT_NUL;
++p;
}
if (current_type == DBUS_TYPE_BOOLEAN)
{
dbus_uint32_t v = _dbus_unpack_uint32 (byte_order,
p);
if (!(v == 0 || v == 1))
return DBUS_INVALID_BOOLEAN_NOT_ZERO_OR_ONE;
}
p += alignment;
break;
case DBUS_TYPE_ARRAY:
case DBUS_TYPE_STRING:
case DBUS_TYPE_OBJECT_PATH:
{
dbus_uint32_t claimed_len;
a = _DBUS_ALIGN_ADDRESS (p, 4);
if (a + 4 > end)
return DBUS_INVALID_NOT_ENOUGH_DATA;
while (p != a)
{
if (*p != '\0')
return DBUS_INVALID_ALIGNMENT_PADDING_NOT_NUL;
++p;
}
claimed_len = _dbus_unpack_uint32 (byte_order, p);
p += 4;
/* p may now be == end */
_dbus_assert (p <= end);
if (current_type == DBUS_TYPE_ARRAY)
{
int array_elem_type = _dbus_type_reader_get_element_type (reader);
alignment = _dbus_type_get_alignment (array_elem_type);
p = _DBUS_ALIGN_ADDRESS (p, alignment);
}
if (claimed_len > (unsigned long) (end - p))
return DBUS_INVALID_LENGTH_OUT_OF_BOUNDS;
if (current_type == DBUS_TYPE_OBJECT_PATH)
{
DBusString str;
_dbus_string_init_const_len (&str, p, claimed_len);
if (!_dbus_validate_path (&str, 0,
_dbus_string_get_length (&str)))
return DBUS_INVALID_BAD_PATH;
p += claimed_len;
}
else if (current_type == DBUS_TYPE_STRING)
{
DBusString str;
_dbus_string_init_const_len (&str, p, claimed_len);
if (!_dbus_string_validate_utf8 (&str, 0,
_dbus_string_get_length (&str)))
return DBUS_INVALID_BAD_UTF8_IN_STRING;
p += claimed_len;
}
else if (current_type == DBUS_TYPE_ARRAY && claimed_len > 0)
{
DBusTypeReader sub;
DBusValidity validity;
const unsigned char *array_end;
if (claimed_len > DBUS_MAXIMUM_ARRAY_LENGTH)
return DBUS_INVALID_ARRAY_LENGTH_EXCEEDS_MAXIMUM;
/* Remember that the reader is types only, so we can't
* use it to iterate over elements. It stays the same
* for all elements.
*/
_dbus_type_reader_recurse (reader, &sub);
array_end = p + claimed_len;
while (p < array_end)
{
/* FIXME we are calling a function per array element! very bad
* need if (dbus_type_is_fixed(elem_type)) here to just skip
* big blocks of ints/bytes/etc.
*/
validity = validate_body_helper (&sub, byte_order, FALSE, p, end, &p);
if (validity != DBUS_VALID)
return validity;
}
if (p != array_end)
return DBUS_INVALID_ARRAY_LENGTH_INCORRECT;
}
/* check nul termination */
if (current_type != DBUS_TYPE_ARRAY)
{
if (p == end)
return DBUS_INVALID_NOT_ENOUGH_DATA;
if (*p != '\0')
return DBUS_INVALID_STRING_MISSING_NUL;
++p;
}
}
break;
case DBUS_TYPE_SIGNATURE:
{
dbus_uint32_t claimed_len;
DBusString str;
DBusValidity validity;
claimed_len = *p;
++p;
/* 1 is for nul termination */
if (claimed_len + 1 > (unsigned long) (end - p))
return DBUS_INVALID_SIGNATURE_LENGTH_OUT_OF_BOUNDS;
_dbus_string_init_const_len (&str, p, claimed_len);
validity =
_dbus_validate_signature_with_reason (&str, 0,
_dbus_string_get_length (&str));
if (validity != DBUS_VALID)
return validity;
p += claimed_len;
_dbus_assert (p < end);
if (*p != DBUS_TYPE_INVALID)
return DBUS_INVALID_SIGNATURE_MISSING_NUL;
++p;
_dbus_verbose ("p = %p end = %p claimed_len %u\n", p, end, claimed_len);
}
break;
case DBUS_TYPE_VARIANT:
{
/* 1 byte sig len, sig typecodes, align to
* contained-type-boundary, values.
*/
/* In addition to normal signature validation, we need to be sure
* the signature contains only a single (possibly container) type.
*/
dbus_uint32_t claimed_len;
DBusString sig;
DBusTypeReader sub;
DBusValidity validity;
int contained_alignment;
int contained_type;
DBusValidity reason;
claimed_len = *p;
++p;
/* + 1 for nul */
if (claimed_len + 1 > (unsigned long) (end - p))
return DBUS_INVALID_VARIANT_SIGNATURE_LENGTH_OUT_OF_BOUNDS;
_dbus_string_init_const_len (&sig, p, claimed_len);
reason = _dbus_validate_signature_with_reason (&sig, 0,
_dbus_string_get_length (&sig));
if (!(reason == DBUS_VALID))
{
if (reason == DBUS_VALIDITY_UNKNOWN_OOM_ERROR)
return reason;
else
return DBUS_INVALID_VARIANT_SIGNATURE_BAD;
}
p += claimed_len;
if (*p != DBUS_TYPE_INVALID)
return DBUS_INVALID_VARIANT_SIGNATURE_MISSING_NUL;
++p;
contained_type = _dbus_first_type_in_signature (&sig, 0);
if (contained_type == DBUS_TYPE_INVALID)
return DBUS_INVALID_VARIANT_SIGNATURE_EMPTY;
contained_alignment = _dbus_type_get_alignment (contained_type);
a = _DBUS_ALIGN_ADDRESS (p, contained_alignment);
if (a > end)
return DBUS_INVALID_NOT_ENOUGH_DATA;
while (p != a)
{
if (*p != '\0')
return DBUS_INVALID_ALIGNMENT_PADDING_NOT_NUL;
++p;
}
_dbus_type_reader_init_types_only (&sub, &sig, 0);
_dbus_assert (_dbus_type_reader_get_current_type (&sub) != DBUS_TYPE_INVALID);
validity = validate_body_helper (&sub, byte_order, FALSE, p, end, &p);
if (validity != DBUS_VALID)
return validity;
if (_dbus_type_reader_next (&sub))
return DBUS_INVALID_VARIANT_SIGNATURE_SPECIFIES_MULTIPLE_VALUES;
_dbus_assert (_dbus_type_reader_get_current_type (&sub) == DBUS_TYPE_INVALID);
}
break;
case DBUS_TYPE_DICT_ENTRY:
case DBUS_TYPE_STRUCT:
{
DBusTypeReader sub;
DBusValidity validity;
a = _DBUS_ALIGN_ADDRESS (p, 8);
if (a > end)
return DBUS_INVALID_NOT_ENOUGH_DATA;
while (p != a)
{
if (*p != '\0')
return DBUS_INVALID_ALIGNMENT_PADDING_NOT_NUL;
++p;
}
_dbus_type_reader_recurse (reader, &sub);
validity = validate_body_helper (&sub, byte_order, TRUE, p, end, &p);
if (validity != DBUS_VALID)
return validity;
}
break;
default:
_dbus_assert_not_reached ("invalid typecode in supposedly-validated signature");
break;
}
#if 0
_dbus_verbose (" validated value of type %s type reader %p type_pos %d p %p end %p %d remain\n",
_dbus_type_to_string (current_type), reader, reader->type_pos, p, end,
(int) (end - p));
#endif
if (p > end)
{
_dbus_verbose ("not enough data!!! p = %p end = %p end-p = %d\n",
p, end, (int) (end - p));
return DBUS_INVALID_NOT_ENOUGH_DATA;
}
if (walk_reader_to_end)
_dbus_type_reader_next (reader);
else
break;
}
if (new_p)
*new_p = p;
return DBUS_VALID;
}
/* note: this function is also used to validate the header's values,
* since the header is a valid body with a particular signature.
*/
static DBusValidity
validate_body_helper (DBusTypeReader *reader,
int byte_order,
dbus_bool_t walk_reader_to_end,
int total_depth,
const unsigned char *p,
const unsigned char *end,
const unsigned char **new_p)
{
int current_type;
/* The spec allows arrays and structs to each nest 32, for total
* nesting of 2*32. We want to impose the same limit on "dynamic"
* value nesting (not visible in the signature) which is introduced
* by DBUS_TYPE_VARIANT.
*/
if (total_depth > (DBUS_MAXIMUM_TYPE_RECURSION_DEPTH * 2))
{
return DBUS_INVALID_NESTED_TOO_DEEPLY;
}
while ((current_type = _dbus_type_reader_get_current_type (reader)) != DBUS_TYPE_INVALID)
{
const unsigned char *a;
int alignment;
#if 0
_dbus_verbose (" validating value of type %s type reader %p type_pos %d p %p end %p %d remain\n",
_dbus_type_to_string (current_type), reader, reader->type_pos, p, end,
(int) (end - p));
#endif
/* Guarantee that p has one byte to look at */
if (p == end)
return DBUS_INVALID_NOT_ENOUGH_DATA;
switch (current_type)
{
case DBUS_TYPE_BYTE:
++p;
break;
case DBUS_TYPE_BOOLEAN:
case DBUS_TYPE_INT16:
case DBUS_TYPE_UINT16:
case DBUS_TYPE_INT32:
case DBUS_TYPE_UINT32:
case DBUS_TYPE_UNIX_FD:
case DBUS_TYPE_INT64:
case DBUS_TYPE_UINT64:
case DBUS_TYPE_DOUBLE:
alignment = _dbus_type_get_alignment (current_type);
a = _DBUS_ALIGN_ADDRESS (p, alignment);
if (a >= end)
return DBUS_INVALID_NOT_ENOUGH_DATA;
while (p != a)
{
if (*p != '\0')
return DBUS_INVALID_ALIGNMENT_PADDING_NOT_NUL;
++p;
}
if (current_type == DBUS_TYPE_BOOLEAN)
{
dbus_uint32_t v = _dbus_unpack_uint32 (byte_order,
p);
if (!(v == 0 || v == 1))
return DBUS_INVALID_BOOLEAN_NOT_ZERO_OR_ONE;
}
p += alignment;
break;
case DBUS_TYPE_ARRAY:
case DBUS_TYPE_STRING:
case DBUS_TYPE_OBJECT_PATH:
{
dbus_uint32_t claimed_len;
a = _DBUS_ALIGN_ADDRESS (p, 4);
if (a + 4 > end)
return DBUS_INVALID_NOT_ENOUGH_DATA;
while (p != a)
{
if (*p != '\0')
return DBUS_INVALID_ALIGNMENT_PADDING_NOT_NUL;
++p;
}
claimed_len = _dbus_unpack_uint32 (byte_order, p);
p += 4;
/* p may now be == end */
_dbus_assert (p <= end);
if (current_type == DBUS_TYPE_ARRAY)
{
int array_elem_type = _dbus_type_reader_get_element_type (reader);
if (!dbus_type_is_valid (array_elem_type))
{
return DBUS_INVALID_UNKNOWN_TYPECODE;
}
alignment = _dbus_type_get_alignment (array_elem_type);
a = _DBUS_ALIGN_ADDRESS (p, alignment);
/* a may now be == end */
if (a > end)
return DBUS_INVALID_NOT_ENOUGH_DATA;
while (p != a)
{
if (*p != '\0')
return DBUS_INVALID_ALIGNMENT_PADDING_NOT_NUL;
++p;
}
}
if (claimed_len > (unsigned long) (end - p))
return DBUS_INVALID_LENGTH_OUT_OF_BOUNDS;
if (current_type == DBUS_TYPE_OBJECT_PATH)
{
DBusString str;
_dbus_string_init_const_len (&str, (const char *) p, claimed_len);
if (!_dbus_validate_path (&str, 0,
_dbus_string_get_length (&str)))
return DBUS_INVALID_BAD_PATH;
p += claimed_len;
}
else if (current_type == DBUS_TYPE_STRING)
{
DBusString str;
_dbus_string_init_const_len (&str, (const char *) p, claimed_len);
if (!_dbus_string_validate_utf8 (&str, 0,
_dbus_string_get_length (&str)))
return DBUS_INVALID_BAD_UTF8_IN_STRING;
p += claimed_len;
}
else if (current_type == DBUS_TYPE_ARRAY && claimed_len > 0)
{
DBusTypeReader sub;
DBusValidity validity;
const unsigned char *array_end;
int array_elem_type;
if (claimed_len > DBUS_MAXIMUM_ARRAY_LENGTH)
return DBUS_INVALID_ARRAY_LENGTH_EXCEEDS_MAXIMUM;
/* Remember that the reader is types only, so we can't
* use it to iterate over elements. It stays the same
* for all elements.
*/
_dbus_type_reader_recurse (reader, &sub);
array_end = p + claimed_len;
array_elem_type = _dbus_type_reader_get_element_type (reader);
/* avoid recursive call to validate_body_helper if this is an array
* of fixed-size elements
*/
if (dbus_type_is_fixed (array_elem_type))
{
/* bools need to be handled differently, because they can
* have an invalid value
*/
if (array_elem_type == DBUS_TYPE_BOOLEAN)
{
dbus_uint32_t v;
alignment = _dbus_type_get_alignment (array_elem_type);
while (p < array_end)
{
v = _dbus_unpack_uint32 (byte_order, p);
if (!(v == 0 || v == 1))
return DBUS_INVALID_BOOLEAN_NOT_ZERO_OR_ONE;
p += alignment;
}
}
else
{
p = array_end;
}
}
else
{
while (p < array_end)
{
validity = validate_body_helper (&sub, byte_order, FALSE,
total_depth + 1,
p, end, &p);
if (validity != DBUS_VALID)
return validity;
}
}
if (p != array_end)
return DBUS_INVALID_ARRAY_LENGTH_INCORRECT;
}
/* check nul termination */
if (current_type != DBUS_TYPE_ARRAY)
{
if (p == end)
return DBUS_INVALID_NOT_ENOUGH_DATA;
if (*p != '\0')
return DBUS_INVALID_STRING_MISSING_NUL;
++p;
}
}
break;
case DBUS_TYPE_SIGNATURE:
{
dbus_uint32_t claimed_len;
DBusString str;
DBusValidity validity;
claimed_len = *p;
++p;
/* 1 is for nul termination */
if (claimed_len + 1 > (unsigned long) (end - p))
return DBUS_INVALID_SIGNATURE_LENGTH_OUT_OF_BOUNDS;
_dbus_string_init_const_len (&str, (const char *) p, claimed_len);
validity =
_dbus_validate_signature_with_reason (&str, 0,
_dbus_string_get_length (&str));
if (validity != DBUS_VALID)
return validity;
p += claimed_len;
_dbus_assert (p < end);
if (*p != DBUS_TYPE_INVALID)
return DBUS_INVALID_SIGNATURE_MISSING_NUL;
++p;
_dbus_verbose ("p = %p end = %p claimed_len %u\n", p, end, claimed_len);
}
break;
case DBUS_TYPE_VARIANT:
{
/* 1 byte sig len, sig typecodes, align to
* contained-type-boundary, values.
*/
/* In addition to normal signature validation, we need to be sure
* the signature contains only a single (possibly container) type.
*/
dbus_uint32_t claimed_len;
DBusString sig;
DBusTypeReader sub;
DBusValidity validity;
int contained_alignment;
int contained_type;
DBusValidity reason;
claimed_len = *p;
++p;
/* + 1 for nul */
if (claimed_len + 1 > (unsigned long) (end - p))
return DBUS_INVALID_VARIANT_SIGNATURE_LENGTH_OUT_OF_BOUNDS;
_dbus_string_init_const_len (&sig, (const char *) p, claimed_len);
reason = _dbus_validate_signature_with_reason (&sig, 0,
_dbus_string_get_length (&sig));
if (!(reason == DBUS_VALID))
{
if (reason == DBUS_VALIDITY_UNKNOWN_OOM_ERROR)
return reason;
else
return DBUS_INVALID_VARIANT_SIGNATURE_BAD;
}
p += claimed_len;
if (*p != DBUS_TYPE_INVALID)
return DBUS_INVALID_VARIANT_SIGNATURE_MISSING_NUL;
++p;
contained_type = _dbus_first_type_in_signature (&sig, 0);
if (contained_type == DBUS_TYPE_INVALID)
return DBUS_INVALID_VARIANT_SIGNATURE_EMPTY;
contained_alignment = _dbus_type_get_alignment (contained_type);
a = _DBUS_ALIGN_ADDRESS (p, contained_alignment);
if (a > end)
return DBUS_INVALID_NOT_ENOUGH_DATA;
while (p != a)
{
if (*p != '\0')
return DBUS_INVALID_ALIGNMENT_PADDING_NOT_NUL;
++p;
}
_dbus_type_reader_init_types_only (&sub, &sig, 0);
_dbus_assert (_dbus_type_reader_get_current_type (&sub) != DBUS_TYPE_INVALID);
validity = validate_body_helper (&sub, byte_order, FALSE,
total_depth + 1,
p, end, &p);
if (validity != DBUS_VALID)
return validity;
if (_dbus_type_reader_next (&sub))
return DBUS_INVALID_VARIANT_SIGNATURE_SPECIFIES_MULTIPLE_VALUES;
_dbus_assert (_dbus_type_reader_get_current_type (&sub) == DBUS_TYPE_INVALID);
}
break;
case DBUS_TYPE_DICT_ENTRY:
case DBUS_TYPE_STRUCT:
{
DBusTypeReader sub;
DBusValidity validity;
a = _DBUS_ALIGN_ADDRESS (p, 8);
if (a > end)
return DBUS_INVALID_NOT_ENOUGH_DATA;
while (p != a)
{
if (*p != '\0')
return DBUS_INVALID_ALIGNMENT_PADDING_NOT_NUL;
++p;
}
_dbus_type_reader_recurse (reader, &sub);
validity = validate_body_helper (&sub, byte_order, TRUE,
total_depth + 1,
p, end, &p);
if (validity != DBUS_VALID)
return validity;
}
break;
default:
_dbus_assert_not_reached ("invalid typecode in supposedly-validated signature");
break;
}
#if 0
_dbus_verbose (" validated value of type %s type reader %p type_pos %d p %p end %p %d remain\n",
_dbus_type_to_string (current_type), reader, reader->type_pos, p, end,
(int) (end - p));
#endif
if (p > end)
{
_dbus_verbose ("not enough data!!! p = %p end = %p end-p = %d\n",
p, end, (int) (end - p));
return DBUS_INVALID_NOT_ENOUGH_DATA;
}
if (walk_reader_to_end)
_dbus_type_reader_next (reader);
else
break;
}
if (new_p)
*new_p = p;
return DBUS_VALID;
}
