1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
|
// Copyright 2017 The Chromium Authors. All rights reserved.
// Copyright (C) 2018 Apple Inc. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#pragma once
#if ENABLE(WEB_AUTHN)
#include "CBORValue.h"
#include <stddef.h>
// A basic Concise Binary Object Representation (CBOR) encoder as defined by
// https://tools.ietf.org/html/rfc7049. This is a generic encoder that supplies
// canonical, well-formed CBOR values but does not guarantee their validity
// (see https://tools.ietf.org/html/rfc7049#section-3.2).
// Supported:
// * Major types:
// * 0: Unsigned integers, up to INT64_MAX.
// * 1: Negative integers, to INT64_MIN.
// * 2: Byte strings.
// * 3: UTF-8 strings.
// * 4: Arrays, with the number of elements known at the start.
// * 5: Maps, with the number of elements known at the start
// of the container.
// * 7: Simple values.
//
// Unsupported:
// * Floating-point numbers.
// * Indefinite-length encodings.
// * Parsing.
//
// Requirements for canonical CBOR as suggested by RFC 7049 are:
// 1) All major data types for the CBOR values must be as short as possible.
// * Unsigned integer between 0 to 23 must be expressed in same byte as
// the major type.
// * 24 to 255 must be expressed only with an additional uint8_t.
// * 256 to 65535 must be expressed only with an additional uint16_t.
// * 65536 to 4294967295 must be expressed only with an additional
// uint32_t. * The rules for expression of length in major types
// 2 to 5 follow the above rule for integers.
// 2) Keys in every map must be sorted (first by major type, then by key
// length, then by value in byte-wise lexical order).
// 3) Indefinite length items must be converted to definite length items.
// 4) All maps must not have duplicate keys.
//
// Current implementation of CBORWriter encoder meets all the requirements of
// canonical CBOR.
namespace cbor {
class CBORWriter {
WTF_MAKE_NONCOPYABLE(CBORWriter);
public:
// Default that should be sufficiently large for most use cases.
static constexpr size_t kDefaultMaxNestingDepth = 16;
~CBORWriter();
// Returns the CBOR byte string representation of |node|, unless its nesting
// depth is greater than |max_nesting_depth|, in which case an empty optional
// value is returned. The nesting depth of |node| is defined as the number of
// arrays/maps that has to be traversed to reach the most nested CBORValue
// contained in |node|. Primitive values and empty containers have nesting
// depths of 0.
WEBCORE_EXPORT static std::optional<Vector<uint8_t>> write(const CBORValue&, size_t maxNestingLevel = kDefaultMaxNestingDepth);
private:
explicit CBORWriter(Vector<uint8_t>*);
// Called recursively to build the CBOR bytestring. When completed,
// |m_encodedCBOR| will contain the CBOR.
bool encodeCBOR(const CBORValue&, int maxNestingLevel);
// Encodes the type and size of the data being added.
void startItem(CBORValue::Type, uint64_t size);
// Encodes the additional information for the data.
void setAdditionalInformation(uint8_t);
// Encodes an unsigned integer value. This is used to both write
// unsigned integers and to encode the lengths of other major types.
void setUint(uint64_t value);
// Get the number of bytes needed to store the unsigned integer.
size_t getNumUintBytes(uint64_t value);
// Holds the encoded CBOR data.
Vector<uint8_t>* m_encodedCBOR;
};
} // namespace cbor
#endif // ENABLE(WEB_AUTHN)
|
