[ViewVC] Diff of: cvs/CBOR-XS/XS.pm

Comparing CBOR-XS/XS.pm (file contents):
Revision 1.67 by root, Thu Nov 15 19:52:41 2018 UTC vs.
Revision 1.85 by root, Thu Nov 4 16:49:35 2021 UTC

…		…
38	with the added ability of supporting serialisation of Perl objects. (JSON	38	with the added ability of supporting serialisation of Perl objects. (JSON
39	often compresses better than CBOR though, so if you plan to compress the	39	often compresses better than CBOR though, so if you plan to compress the
40	data later and speed is less important you might want to compare both	40	data later and speed is less important you might want to compare both
41	formats first).	41	formats first).
42		42
		43	The primary goal of this module is to be I<correct> and the secondary goal
		44	is to be I<fast>. To reach the latter goal it was written in C.
		45
43	To give you a general idea about speed, with texts in the megabyte range,	46	To give you a general idea about speed, with texts in the megabyte range,
44	C<CBOR::XS> usually encodes roughly twice as fast as L<Storable> or	47	C<CBOR::XS> usually encodes roughly twice as fast as L<Storable> or
45	L<JSON::XS> and decodes about 15%-30% faster than those. The shorter the	48	L<JSON::XS> and decodes about 15%-30% faster than those. The shorter the
46	data, the worse L<Storable> performs in comparison.	49	data, the worse L<Storable> performs in comparison.
47		50
…		…
52	In addition to the core CBOR data format, this module implements a	55	In addition to the core CBOR data format, this module implements a
53	number of extensions, to support cyclic and shared data structures	56	number of extensions, to support cyclic and shared data structures
54	(see C<allow_sharing> and C<allow_cycles>), string deduplication (see	57	(see C<allow_sharing> and C<allow_cycles>), string deduplication (see
55	C<pack_strings>) and scalar references (always enabled).	58	C<pack_strings>) and scalar references (always enabled).
56		59
57	The primary goal of this module is to be I<correct> and the secondary goal
58	is to be I<fast>. To reach the latter goal it was written in C.
59
60	See MAPPING, below, on how CBOR::XS maps perl values to CBOR values and	60	See MAPPING, below, on how CBOR::XS maps perl values to CBOR values and
61	vice versa.	61	vice versa.
62		62
63	=cut	63	=cut
64		64
65	package CBOR::XS;	65	package CBOR::XS;
66		66
67	use common::sense;	67	use common::sense;
68		68
69	our $VERSION = 1.71;	69	our $VERSION = 1.86;
70	our @ISA = qw(Exporter);	70	our @ISA = qw(Exporter);
71		71
72	our @EXPORT = qw(encode_cbor decode_cbor);	72	our @EXPORT = qw(encode_cbor decode_cbor);
73		73
74	use Exporter;	74	use Exporter;
…		…
121	but configures the coder object to be safe to use with untrusted	121	but configures the coder object to be safe to use with untrusted
122	data. Currently, this is equivalent to:	122	data. Currently, this is equivalent to:
123		123
124	my $cbor = CBOR::XS	124	my $cbor = CBOR::XS
125	->new	125	->new
		126	->validate_utf8
126	->forbid_objects	127	->forbid_objects
127	->filter (\&CBOR::XS::safe_filter)	128	->filter (\&CBOR::XS::safe_filter)
128	->max_size (1e8);	129	->max_size (1e8);
129		130
130	But is more future proof (it is better to crash because of a change than	131	But is more future proof (it is better to crash because of a change than
…		…
133	=cut	134	=cut
134		135
135	sub new_safe {	136	sub new_safe {
136	CBOR::XS	137	CBOR::XS
137	->new	138	->new
		139	->validate_utf8
138	->forbid_objects	140	->forbid_objects
139	->filter (\&CBOR::XS::safe_filter)	141	->filter (\&CBOR::XS::safe_filter)
140	->max_size (1e8)	142	->max_size (1e8)
141	}	143	}
142		144
…		…
215	(L<http://cbor.schmorp.de/value-sharing>), as without decoder support, the	217	(L<http://cbor.schmorp.de/value-sharing>), as without decoder support, the
216	resulting data structure might be unusable.	218	resulting data structure might be unusable.
217		219
218	Detecting shared values incurs a runtime overhead when values are encoded	220	Detecting shared values incurs a runtime overhead when values are encoded
219	that have a reference counter large than one, and might unnecessarily	221	that have a reference counter large than one, and might unnecessarily
220	increase the encoded size, as potentially shared values are encode as	222	increase the encoded size, as potentially shared values are encoded as
221	shareable whether or not they are actually shared.	223	shareable whether or not they are actually shared.
222		224
223	At the moment, only targets of references can be shared (e.g. scalars,	225	At the moment, only targets of references can be shared (e.g. scalars,
224	arrays or hashes pointed to by a reference). Weirder constructs, such as	226	arrays or hashes pointed to by a reference). Weirder constructs, such as
225	an array with multiple "copies" of the I<same> string, which are hard but	227	an array with multiple "copies" of the I<same> string, which are hard but
…		…
330	strings as CBOR byte strings.	332	strings as CBOR byte strings.
331		333
332	This option does not affect C<decode> in any way.	334	This option does not affect C<decode> in any way.
333		335
334	This option has similar advantages and disadvantages as C<text_keys>. In	336	This option has similar advantages and disadvantages as C<text_keys>. In
335	addition, this option effectively removes the ability to encode byte	337	addition, this option effectively removes the ability to automatically
336	strings, which might break some C<FREEZE> and C<TO_CBOR> methods that rely	338	encode byte strings, which might break some C<FREEZE> and C<TO_CBOR>
337	on this, such as bignum encoding, so this option is mainly useful for very	339	methods that rely on this.
338	simple data.	340
		341	A workaround is to use explicit type casts, which are unaffected by this option.
339		342
340	=item $cbor = $cbor->validate_utf8 ([$enable])	343	=item $cbor = $cbor->validate_utf8 ([$enable])
341		344
342	=item $enabled = $cbor->get_validate_utf8	345	=item $enabled = $cbor->get_validate_utf8
343		346
…		…
453	when there is trailing garbage after the CBOR string, it will silently	456	when there is trailing garbage after the CBOR string, it will silently
454	stop parsing there and return the number of characters consumed so far.	457	stop parsing there and return the number of characters consumed so far.
455		458
456	This is useful if your CBOR texts are not delimited by an outer protocol	459	This is useful if your CBOR texts are not delimited by an outer protocol
457	and you need to know where the first CBOR string ends amd the next one	460	and you need to know where the first CBOR string ends amd the next one
458	starts.	461	starts - CBOR strings are self-delimited, so it is possible to concatenate
		462	CBOR strings without any delimiters or size fields and recover their data.
459		463
460	CBOR::XS->new->decode_prefix ("......")	464	CBOR::XS->new->decode_prefix ("......")
461	=> ("...", 3)	465	=> ("...", 3)
462		466
463	=back	467	=back
…		…
667	"$x"; # stringified	671	"$x"; # stringified
668	$x .= ""; # another, more awkward way to stringify	672	$x .= ""; # another, more awkward way to stringify
669	print $x; # perl does it for you, too, quite often	673	print $x; # perl does it for you, too, quite often
670		674
671	You can force whether a string is encoded as byte or text string by using	675	You can force whether a string is encoded as byte or text string by using
672	C<utf8::upgrade> and C<utf8::downgrade> (if C<text_strings> is disabled):	676	C<utf8::upgrade> and C<utf8::downgrade> (if C<text_strings> is disabled).
673		677
674	utf8::upgrade $x; # encode $x as text string	678	utf8::upgrade $x; # encode $x as text string
675	utf8::downgrade $x; # encode $x as byte string	679	utf8::downgrade $x; # encode $x as byte string
		680
		681	More options are available, see L<TYPE CASTS>, below, and the C<text_keys>
		682	and C<text_strings> options.
676		683
677	Perl doesn't define what operations up- and downgrade strings, so if the	684	Perl doesn't define what operations up- and downgrade strings, so if the
678	difference between byte and text is important, you should up- or downgrade	685	difference between byte and text is important, you should up- or downgrade
679	your string as late as possible before encoding. You can also force the	686	your string as late as possible before encoding. You can also force the
680	use of CBOR text strings by using C<text_keys> or C<text_strings>.	687	use of CBOR text strings by using C<text_keys> or C<text_strings>.
…		…
695	format will be used. Perls that use formats other than IEEE double to	702	format will be used. Perls that use formats other than IEEE double to
696	represent numerical values are supported, but might suffer loss of	703	represent numerical values are supported, but might suffer loss of
697	precision.	704	precision.
698		705
699	=back	706	=back
		707
		708	=head2 TYPE CASTS
		709
		710	B<EXPERIMENTAL>: As an experimental extension, C<CBOR::XS> allows you to
		711	force specific CBOR types to be used when encoding. That allows you to
		712	encode types not normally accessible (e.g. half floats) as well as force
		713	string types even when C<text_strings> is in effect.
		714
		715	Type forcing is done by calling a special "cast" function which keeps a
		716	copy of the value and returns a new value that can be handed over to any
		717	CBOR encoder function.
		718
		719	The following casts are currently available (all of which are unary
		720	operators, that is, have a prototype of C<$>):
		721
		722	=over
		723
		724	=item CBOR::XS::as_int $value
		725
		726	Forces the value to be encoded as some form of (basic, not bignum) integer
		727	type.
		728
		729	=item CBOR::XS::as_text $value
		730
		731	Forces the value to be encoded as (UTF-8) text values.
		732
		733	=item CBOR::XS::as_bytes $value
		734
		735	Forces the value to be encoded as a (binary) string value.
		736
		737	Example: encode a perl string as binary even though C<text_strings> is in
		738	effect.
		739
		740	CBOR::XS->new->text_strings->encode ([4, "text", CBOR::XS::bytes "bytevalue"]);
		741
		742	=item CBOR::XS::as_bool $value
		743
		744	Converts a Perl boolean (which can be any kind of scalar) into a CBOR
		745	boolean. Strictly the same, but shorter to write, than:
		746
		747	$value ? Types::Serialiser::true : Types::Serialiser::false
		748
		749	=item CBOR::XS::as_float16 $value
		750
		751	Forces half-float (IEEE 754 binary16) encoding of the given value.
		752
		753	=item CBOR::XS::as_float32 $value
		754
		755	Forces single-float (IEEE 754 binary32) encoding of the given value.
		756
		757	=item CBOR::XS::as_float64 $value
		758
		759	Forces double-float (IEEE 754 binary64) encoding of the given value.
		760
		761	=item CBOR::XS::as_cbor $cbor_text
		762
		763	Not a type cast per-se, this type cast forces the argument to be encoded
		764	as-is. This can be used to embed pre-encoded CBOR data.
		765
		766	Note that no checking on the validity of the C<$cbor_text> is done - it's
		767	the callers responsibility to correctly encode values.
		768
		769	=item CBOR::XS::as_map [key => value...]
		770
		771	Treat the array reference as key value pairs and output a CBOR map. This
		772	allows you to generate CBOR maps with arbitrary key types (or, if you
		773	don't care about semantics, duplicate keys or pairs in a custom order),
		774	which is otherwise hard to do with Perl.
		775
		776	The single argument must be an array reference with an even number of
		777	elements.
		778
		779	Note that only the reference to the array is copied, the array itself is
		780	not. Modifications done to the array before calling an encoding function
		781	will be reflected in the encoded output.
		782
		783	Example: encode a CBOR map with a string and an integer as keys.
		784
		785	encode_cbor CBOR::XS::as_map [string => "value", 5 => "value"]
		786
		787	=back
		788
		789	=cut
		790
		791	sub CBOR::XS::as_cbor ($) { bless [$_[0], 0, undef], CBOR::XS::Tagged:: }
		792	sub CBOR::XS::as_int ($) { bless [$_[0], 1, undef], CBOR::XS::Tagged:: }
		793	sub CBOR::XS::as_bytes ($) { bless [$_[0], 2, undef], CBOR::XS::Tagged:: }
		794	sub CBOR::XS::as_text ($) { bless [$_[0], 3, undef], CBOR::XS::Tagged:: }
		795	sub CBOR::XS::as_float16 ($) { bless [$_[0], 4, undef], CBOR::XS::Tagged:: }
		796	sub CBOR::XS::as_float32 ($) { bless [$_[0], 5, undef], CBOR::XS::Tagged:: }
		797	sub CBOR::XS::as_float64 ($) { bless [$_[0], 6, undef], CBOR::XS::Tagged:: }
		798
		799	sub CBOR::XS::as_bool ($) { $_[0] ? $Types::Serialiser::true : $Types::Serialiser::false }
		800
		801	sub CBOR::XS::as_map ($) {
		802	ARRAY:: eq ref $_[0]
		803	and $#{ $_[0] } & 1
		804	or do { require Carp; Carp::croak ("CBOR::XS::as_map only acepts array references with an even number of elements, caught") };
		805
		806	bless [$_[0], 7, undef], CBOR::XS::Tagged::
		807	}
700		808
701	=head2 OBJECT SERIALISATION	809	=head2 OBJECT SERIALISATION
702		810
703	This module implements both a CBOR-specific and the generic	811	This module implements both a CBOR-specific and the generic
704	L<Types::Serialier> object serialisation protocol. The following	812	L<Types::Serialier> object serialisation protocol. The following
…		…
1057		1165
1058		1166
1059	=head1 SECURITY CONSIDERATIONS	1167	=head1 SECURITY CONSIDERATIONS
1060		1168
1061	Tl;dr... if you want to decode or encode CBOR from untrusted sources, you	1169	Tl;dr... if you want to decode or encode CBOR from untrusted sources, you
1062	should start with a coder object created via C<new_safe>:	1170	should start with a coder object created via C<new_safe> (which implements
		1171	the mitigations explained below):
1063		1172
1064	my $coder = CBOR::XS->new_safe;	1173	my $coder = CBOR::XS->new_safe;
1065		1174
1066	my $data = $coder->decode ($cbor_text);	1175	my $data = $coder->decode ($cbor_text);
1067	my $cbor = $coder->encode ($data);	1176	my $cbor = $coder->encode ($data);
…		…
1089	even if all your C<THAW> methods are secure, encoding data structures from	1198	even if all your C<THAW> methods are secure, encoding data structures from
1090	untrusted sources can invoke those and trigger bugs in those.	1199	untrusted sources can invoke those and trigger bugs in those.
1091		1200
1092	So, if you are not sure about the security of all the modules you	1201	So, if you are not sure about the security of all the modules you
1093	have loaded (you shouldn't), you should disable this part using	1202	have loaded (you shouldn't), you should disable this part using
1094	C<forbid_objects>.	1203	C<forbid_objects> or using C<new_safe>.
1095		1204
1096	=item CBOR can be extended with tags that call library code	1205	=item CBOR can be extended with tags that call library code
1097		1206
1098	CBOR can be extended with tags, and C<CBOR::XS> has a registry of	1207	CBOR can be extended with tags, and C<CBOR::XS> has a registry of
1099	conversion functions for many existing tags that can be extended via	1208	conversion functions for many existing tags that can be extended via
1100	third-party modules (see the C<filter> method).	1209	third-party modules (see the C<filter> method).
1101		1210
1102	If you don't trust these, you should configure the "safe" filter function,	1211	If you don't trust these, you should configure the "safe" filter function,
1103	C<CBOR::XS::safe_filter>, which by default only includes conversion	1212	C<CBOR::XS::safe_filter> (C<new_safe> does this), which by default only
1104	functions that are considered "safe" by the author (but again, they can be	1213	includes conversion functions that are considered "safe" by the author
1105	extended by third party modules).	1214	(but again, they can be extended by third party modules).
1106		1215
1107	Depending on your level of paranoia, you can use the "safe" filter:	1216	Depending on your level of paranoia, you can use the "safe" filter:
1108		1217
1109	$cbor->filter (\&CBOR::XS::safe_filter);	1218	$cbor->filter (\&CBOR::XS::safe_filter);
1110		1219
…		…
1125	the size of CBOR data you accept, or make sure then when your resources	1234	the size of CBOR data you accept, or make sure then when your resources
1126	run out, that's just fine (e.g. by using a separate process that can	1235	run out, that's just fine (e.g. by using a separate process that can
1127	crash safely). The size of a CBOR string in octets is usually a good	1236	crash safely). The size of a CBOR string in octets is usually a good
1128	indication of the size of the resources required to decode it into a Perl	1237	indication of the size of the resources required to decode it into a Perl
1129	structure. While CBOR::XS can check the size of the CBOR text (using	1238	structure. While CBOR::XS can check the size of the CBOR text (using
1130	C<max_size>), it might be too late when you already have it in memory, so	1239	C<max_size> - done by C<new_safe>), it might be too late when you already
1131	you might want to check the size before you accept the string.	1240	have it in memory, so you might want to check the size before you accept
		1241	the string.
1132		1242
1133	As for encoding, it is possible to construct data structures that are	1243	As for encoding, it is possible to construct data structures that are
1134	relatively small but result in large CBOR texts (for example by having an	1244	relatively small but result in large CBOR texts (for example by having an
1135	array full of references to the same big data structure, which will all be	1245	array full of references to the same big data structure, which will all be
1136	deep-cloned during encoding by default). This is rarely an actual issue	1246	deep-cloned during encoding by default). This is rarely an actual issue
…		…
1149	method.	1259	method.
1150		1260
1151	=item Resource-starving attacks: CPU en-/decoding complexity	1261	=item Resource-starving attacks: CPU en-/decoding complexity
1152		1262
1153	CBOR::XS will use the L<Math::BigInt>, L<Math::BigFloat> and	1263	CBOR::XS will use the L<Math::BigInt>, L<Math::BigFloat> and
1154	L<Math::BigRat> libraries to represent encode/decode bignums. These can	1264	L<Math::BigRat> libraries to represent encode/decode bignums. These can be
1155	be very slow (as in, centuries of CPU time) and can even crash your	1265	very slow (as in, centuries of CPU time) and can even crash your program
1156	program (and are generally not very trustworthy). See the next section for	1266	(and are generally not very trustworthy). See the next section on bignum
1157	details.	1267	security for details.
1158		1268
1159	=item Data breaches: leaking information in error messages	1269	=item Data breaches: leaking information in error messages
1160		1270
1161	CBOR::XS might leak contents of your Perl data structures in its error	1271	CBOR::XS might leak contents of your Perl data structures in its error
1162	messages, so when you serialise sensitive information you might want to	1272	messages, so when you serialise sensitive information you might want to
…		…
1225	=head1 LIMITATIONS ON PERLS WITHOUT 64-BIT INTEGER SUPPORT	1335	=head1 LIMITATIONS ON PERLS WITHOUT 64-BIT INTEGER SUPPORT
1226		1336
1227	On perls that were built without 64 bit integer support (these are rare	1337	On perls that were built without 64 bit integer support (these are rare
1228	nowadays, even on 32 bit architectures, as all major Perl distributions	1338	nowadays, even on 32 bit architectures, as all major Perl distributions
1229	are built with 64 bit integer support), support for any kind of 64 bit	1339	are built with 64 bit integer support), support for any kind of 64 bit
1230	integer in CBOR is very limited - most likely, these 64 bit values will	1340	value in CBOR is very limited - most likely, these 64 bit values will
1231	be truncated, corrupted, or otherwise not decoded correctly. This also	1341	be truncated, corrupted, or otherwise not decoded correctly. This also
1232	includes string, array and map sizes that are stored as 64 bit integers.	1342	includes string, float, array and map sizes that are stored as 64 bit
		1343	integers.
1233		1344
1234		1345
1235	=head1 THREADS	1346	=head1 THREADS
1236		1347
1237	This module is I<not> guaranteed to be thread safe and there are no	1348	This module is I<not> guaranteed to be thread safe and there are no

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Comparing CBOR-XS/XS.pm (file contents): Revision 1.67 by root, Thu Nov 15 19:52:41 2018 UTC vs. Revision 1.85 by root, Thu Nov 4 16:49:35 2021 UTC

Diff Legend

Comparing CBOR-XS/XS.pm (file contents):
Revision 1.67 by root, Thu Nov 15 19:52:41 2018 UTC vs.
Revision 1.85 by root, Thu Nov 4 16:49:35 2021 UTC