glib/glib/gvarianttype.h
Philip Withnall 7c4e6e9fbe gvarianttype: Impose a recursion limit of 128 on variant types
Previously, GVariant has allowed ‘arbitrary’ recursion on GVariantTypes,
but this isn’t really feasible. We have to deal with GVariants from
untrusted sources, and the nature of GVariantType means that another
level of recursion (and hence, for example, another stack frame in your
application) can be added with a single byte in a variant type signature
in the input. This gives malicious input sources far too much leverage
to cause deep stack recursion or massive memory allocations which can
DoS an application.

Limit recursion to 128 levels (which should be more than enough for
anyone™), document it and add a test. This is, handily, also the limit
of 64 applied by the D-Bus specification (§(Valid Signatures)), plus a
bit to allow wrapping of D-Bus messages in additional layers of
variants.

oss-fuzz#9857

Signed-off-by: Philip Withnall <withnall@endlessm.com>
2018-10-23 17:01:51 +13:00

383 lines
13 KiB
C

/*
* Copyright © 2007, 2008 Ryan Lortie
* Copyright © 2009, 2010 Codethink Limited
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*
* Author: Ryan Lortie <desrt@desrt.ca>
*/
#ifndef __G_VARIANT_TYPE_H__
#define __G_VARIANT_TYPE_H__
#if !defined (__GLIB_H_INSIDE__) && !defined (GLIB_COMPILATION)
#error "Only <glib.h> can be included directly."
#endif
#include <glib/gtypes.h>
G_BEGIN_DECLS
/**
* GVariantType:
*
* A type in the GVariant type system.
*
* Two types may not be compared by value; use g_variant_type_equal() or
* g_variant_type_is_subtype_of(). May be copied using
* g_variant_type_copy() and freed using g_variant_type_free().
**/
typedef struct _GVariantType GVariantType;
/**
* G_VARIANT_TYPE_BOOLEAN:
*
* The type of a value that can be either %TRUE or %FALSE.
**/
#define G_VARIANT_TYPE_BOOLEAN ((const GVariantType *) "b")
/**
* G_VARIANT_TYPE_BYTE:
*
* The type of an integer value that can range from 0 to 255.
**/
#define G_VARIANT_TYPE_BYTE ((const GVariantType *) "y")
/**
* G_VARIANT_TYPE_INT16:
*
* The type of an integer value that can range from -32768 to 32767.
**/
#define G_VARIANT_TYPE_INT16 ((const GVariantType *) "n")
/**
* G_VARIANT_TYPE_UINT16:
*
* The type of an integer value that can range from 0 to 65535.
* There were about this many people living in Toronto in the 1870s.
**/
#define G_VARIANT_TYPE_UINT16 ((const GVariantType *) "q")
/**
* G_VARIANT_TYPE_INT32:
*
* The type of an integer value that can range from -2147483648 to
* 2147483647.
**/
#define G_VARIANT_TYPE_INT32 ((const GVariantType *) "i")
/**
* G_VARIANT_TYPE_UINT32:
*
* The type of an integer value that can range from 0 to 4294967295.
* That's one number for everyone who was around in the late 1970s.
**/
#define G_VARIANT_TYPE_UINT32 ((const GVariantType *) "u")
/**
* G_VARIANT_TYPE_INT64:
*
* The type of an integer value that can range from
* -9223372036854775808 to 9223372036854775807.
**/
#define G_VARIANT_TYPE_INT64 ((const GVariantType *) "x")
/**
* G_VARIANT_TYPE_UINT64:
*
* The type of an integer value that can range from 0
* to 18446744073709551615 (inclusive). That's a really big number,
* but a Rubik's cube can have a bit more than twice as many possible
* positions.
**/
#define G_VARIANT_TYPE_UINT64 ((const GVariantType *) "t")
/**
* G_VARIANT_TYPE_DOUBLE:
*
* The type of a double precision IEEE754 floating point number.
* These guys go up to about 1.80e308 (plus and minus) but miss out on
* some numbers in between. In any case, that's far greater than the
* estimated number of fundamental particles in the observable
* universe.
**/
#define G_VARIANT_TYPE_DOUBLE ((const GVariantType *) "d")
/**
* G_VARIANT_TYPE_STRING:
*
* The type of a string. "" is a string. %NULL is not a string.
**/
#define G_VARIANT_TYPE_STRING ((const GVariantType *) "s")
/**
* G_VARIANT_TYPE_OBJECT_PATH:
*
* The type of a D-Bus object reference. These are strings of a
* specific format used to identify objects at a given destination on
* the bus.
*
* If you are not interacting with D-Bus, then there is no reason to make
* use of this type. If you are, then the D-Bus specification contains a
* precise description of valid object paths.
**/
#define G_VARIANT_TYPE_OBJECT_PATH ((const GVariantType *) "o")
/**
* G_VARIANT_TYPE_SIGNATURE:
*
* The type of a D-Bus type signature. These are strings of a specific
* format used as type signatures for D-Bus methods and messages.
*
* If you are not interacting with D-Bus, then there is no reason to make
* use of this type. If you are, then the D-Bus specification contains a
* precise description of valid signature strings.
**/
#define G_VARIANT_TYPE_SIGNATURE ((const GVariantType *) "g")
/**
* G_VARIANT_TYPE_VARIANT:
*
* The type of a box that contains any other value (including another
* variant).
**/
#define G_VARIANT_TYPE_VARIANT ((const GVariantType *) "v")
/**
* G_VARIANT_TYPE_HANDLE:
*
* The type of a 32bit signed integer value, that by convention, is used
* as an index into an array of file descriptors that are sent alongside
* a D-Bus message.
*
* If you are not interacting with D-Bus, then there is no reason to make
* use of this type.
**/
#define G_VARIANT_TYPE_HANDLE ((const GVariantType *) "h")
/**
* G_VARIANT_TYPE_UNIT:
*
* The empty tuple type. Has only one instance. Known also as "triv"
* or "void".
**/
#define G_VARIANT_TYPE_UNIT ((const GVariantType *) "()")
/**
* G_VARIANT_TYPE_ANY:
*
* An indefinite type that is a supertype of every type (including
* itself).
**/
#define G_VARIANT_TYPE_ANY ((const GVariantType *) "*")
/**
* G_VARIANT_TYPE_BASIC:
*
* An indefinite type that is a supertype of every basic (ie:
* non-container) type.
**/
#define G_VARIANT_TYPE_BASIC ((const GVariantType *) "?")
/**
* G_VARIANT_TYPE_MAYBE:
*
* An indefinite type that is a supertype of every maybe type.
**/
#define G_VARIANT_TYPE_MAYBE ((const GVariantType *) "m*")
/**
* G_VARIANT_TYPE_ARRAY:
*
* An indefinite type that is a supertype of every array type.
**/
#define G_VARIANT_TYPE_ARRAY ((const GVariantType *) "a*")
/**
* G_VARIANT_TYPE_TUPLE:
*
* An indefinite type that is a supertype of every tuple type,
* regardless of the number of items in the tuple.
**/
#define G_VARIANT_TYPE_TUPLE ((const GVariantType *) "r")
/**
* G_VARIANT_TYPE_DICT_ENTRY:
*
* An indefinite type that is a supertype of every dictionary entry
* type.
**/
#define G_VARIANT_TYPE_DICT_ENTRY ((const GVariantType *) "{?*}")
/**
* G_VARIANT_TYPE_DICTIONARY:
*
* An indefinite type that is a supertype of every dictionary type --
* that is, any array type that has an element type equal to any
* dictionary entry type.
**/
#define G_VARIANT_TYPE_DICTIONARY ((const GVariantType *) "a{?*}")
/**
* G_VARIANT_TYPE_STRING_ARRAY:
*
* The type of an array of strings.
**/
#define G_VARIANT_TYPE_STRING_ARRAY ((const GVariantType *) "as")
/**
* G_VARIANT_TYPE_OBJECT_PATH_ARRAY:
*
* The type of an array of object paths.
**/
#define G_VARIANT_TYPE_OBJECT_PATH_ARRAY ((const GVariantType *) "ao")
/**
* G_VARIANT_TYPE_BYTESTRING:
*
* The type of an array of bytes. This type is commonly used to pass
* around strings that may not be valid utf8. In that case, the
* convention is that the nul terminator character should be included as
* the last character in the array.
**/
#define G_VARIANT_TYPE_BYTESTRING ((const GVariantType *) "ay")
/**
* G_VARIANT_TYPE_BYTESTRING_ARRAY:
*
* The type of an array of byte strings (an array of arrays of bytes).
**/
#define G_VARIANT_TYPE_BYTESTRING_ARRAY ((const GVariantType *) "aay")
/**
* G_VARIANT_TYPE_VARDICT:
*
* The type of a dictionary mapping strings to variants (the ubiquitous
* "a{sv}" type).
*
* Since: 2.30
**/
#define G_VARIANT_TYPE_VARDICT ((const GVariantType *) "a{sv}")
/**
* G_VARIANT_TYPE:
* @type_string: a well-formed #GVariantType type string
*
* Converts a string to a const #GVariantType. Depending on the
* current debugging level, this function may perform a runtime check
* to ensure that @string is a valid GVariant type string.
*
* It is always a programmer error to use this macro with an invalid
* type string. If in doubt, use g_variant_type_string_is_valid() to
* check if the string is valid.
*
* Since 2.24
**/
#ifndef G_DISABLE_CHECKS
# define G_VARIANT_TYPE(type_string) (g_variant_type_checked_ ((type_string)))
#else
# define G_VARIANT_TYPE(type_string) ((const GVariantType *) (type_string))
#endif
/* type string checking */
GLIB_AVAILABLE_IN_ALL
gboolean g_variant_type_string_is_valid (const gchar *type_string);
GLIB_AVAILABLE_IN_ALL
gboolean g_variant_type_string_scan (const gchar *string,
const gchar *limit,
const gchar **endptr);
/* create/destroy */
GLIB_AVAILABLE_IN_ALL
void g_variant_type_free (GVariantType *type);
GLIB_AVAILABLE_IN_ALL
GVariantType * g_variant_type_copy (const GVariantType *type);
GLIB_AVAILABLE_IN_ALL
GVariantType * g_variant_type_new (const gchar *type_string);
/* getters */
GLIB_AVAILABLE_IN_ALL
gsize g_variant_type_get_string_length (const GVariantType *type);
GLIB_AVAILABLE_IN_ALL
const gchar * g_variant_type_peek_string (const GVariantType *type);
GLIB_AVAILABLE_IN_ALL
gchar * g_variant_type_dup_string (const GVariantType *type);
/* classification */
GLIB_AVAILABLE_IN_ALL
gboolean g_variant_type_is_definite (const GVariantType *type);
GLIB_AVAILABLE_IN_ALL
gboolean g_variant_type_is_container (const GVariantType *type);
GLIB_AVAILABLE_IN_ALL
gboolean g_variant_type_is_basic (const GVariantType *type);
GLIB_AVAILABLE_IN_ALL
gboolean g_variant_type_is_maybe (const GVariantType *type);
GLIB_AVAILABLE_IN_ALL
gboolean g_variant_type_is_array (const GVariantType *type);
GLIB_AVAILABLE_IN_ALL
gboolean g_variant_type_is_tuple (const GVariantType *type);
GLIB_AVAILABLE_IN_ALL
gboolean g_variant_type_is_dict_entry (const GVariantType *type);
GLIB_AVAILABLE_IN_ALL
gboolean g_variant_type_is_variant (const GVariantType *type);
/* for hash tables */
GLIB_AVAILABLE_IN_ALL
guint g_variant_type_hash (gconstpointer type);
GLIB_AVAILABLE_IN_ALL
gboolean g_variant_type_equal (gconstpointer type1,
gconstpointer type2);
/* subtypes */
GLIB_AVAILABLE_IN_ALL
gboolean g_variant_type_is_subtype_of (const GVariantType *type,
const GVariantType *supertype);
/* type iterator interface */
GLIB_AVAILABLE_IN_ALL
const GVariantType * g_variant_type_element (const GVariantType *type);
GLIB_AVAILABLE_IN_ALL
const GVariantType * g_variant_type_first (const GVariantType *type);
GLIB_AVAILABLE_IN_ALL
const GVariantType * g_variant_type_next (const GVariantType *type);
GLIB_AVAILABLE_IN_ALL
gsize g_variant_type_n_items (const GVariantType *type);
GLIB_AVAILABLE_IN_ALL
const GVariantType * g_variant_type_key (const GVariantType *type);
GLIB_AVAILABLE_IN_ALL
const GVariantType * g_variant_type_value (const GVariantType *type);
/* constructors */
GLIB_AVAILABLE_IN_ALL
GVariantType * g_variant_type_new_array (const GVariantType *element);
GLIB_AVAILABLE_IN_ALL
GVariantType * g_variant_type_new_maybe (const GVariantType *element);
GLIB_AVAILABLE_IN_ALL
GVariantType * g_variant_type_new_tuple (const GVariantType * const *items,
gint length);
GLIB_AVAILABLE_IN_ALL
GVariantType * g_variant_type_new_dict_entry (const GVariantType *key,
const GVariantType *value);
/*< private >*/
GLIB_AVAILABLE_IN_ALL
const GVariantType * g_variant_type_checked_ (const gchar *);
GLIB_AVAILABLE_IN_2_60
gsize g_variant_type_string_get_depth_ (const gchar *type_string);
G_END_DECLS
#endif /* __G_VARIANT_TYPE_H__ */