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
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
|
// Copyright 2021 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "content/browser/webauth/client_data_json.h"
#include <string_view>
#include "base/base64url.h"
#include "base/check.h"
#include "base/containers/span.h"
#include "base/rand_util.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/utf_string_conversion_utils.h"
#include "content/browser/webauth/common_utils.h"
#include "content/public/common/content_features.h"
namespace content {
namespace {
// ToJSONString encodes |in| as a JSON string, using the specific escaping rules
// required by https://github.com/w3c/webauthn/pull/1375.
std::string ToJSONString(std::string_view in) {
std::string ret;
ret.reserve(in.size() + 2);
ret.push_back('"');
base::span<const char> in_bytes = base::span(in);
const size_t length = in.size();
size_t offset = 0;
while (offset < length) {
const size_t prior_offset = offset;
// Input strings must be valid UTF-8.
base_icu::UChar32 codepoint;
CHECK(base::ReadUnicodeCharacter(in_bytes.data(), length, &offset,
&codepoint));
// offset is updated by |ReadUnicodeCharacter| to index the last byte of the
// codepoint. Increment it to index the first byte of the next codepoint for
// the subsequent iteration.
offset++;
if (codepoint == 0x20 || codepoint == 0x21 ||
(codepoint >= 0x23 && codepoint <= 0x5b) || codepoint >= 0x5d) {
ret.append(&in_bytes[prior_offset], offset - prior_offset);
} else if (codepoint == 0x22) {
ret.append("\\\"");
} else if (codepoint == 0x5c) {
ret.append("\\\\");
} else {
ret.append("\\u00");
base::AppendHexEncodedByte(static_cast<uint8_t>(codepoint), ret, false);
}
}
ret.push_back('"');
return ret;
}
} // namespace
ClientDataJsonParams::ClientDataJsonParams(
ClientDataRequestType type,
url::Origin origin,
url::Origin top_origin,
std::optional<std::vector<uint8_t>> challenge,
bool is_cross_origin_iframe)
: type(type),
origin(std::move(origin)),
top_origin(std::move(top_origin)),
challenge(std::move(challenge)),
is_cross_origin_iframe(is_cross_origin_iframe) {}
ClientDataJsonParams::ClientDataJsonParams(ClientDataJsonParams&&) = default;
ClientDataJsonParams& ClientDataJsonParams::operator=(ClientDataJsonParams&&) =
default;
ClientDataJsonParams::~ClientDataJsonParams() = default;
std::string BuildClientDataJson(ClientDataJsonParams params) {
CHECK(params.challenge.has_value());
std::string ret;
ret.reserve(128);
switch (params.type) {
case ClientDataRequestType::kWebAuthnCreate:
ret.append(R"({"type":"webauthn.create")");
break;
case ClientDataRequestType::kWebAuthnGet:
ret.append(R"({"type":"webauthn.get")");
break;
case ClientDataRequestType::kPaymentGet:
ret.append(R"({"type":"payment.get")");
break;
}
ret.append(R"(,"challenge":)");
ret.append(ToJSONString(Base64UrlEncodeOmitPadding(*params.challenge)));
ret.append(R"(,"origin":)");
ret.append(ToJSONString(params.origin.Serialize()));
std::string serialized_top_origin =
ToJSONString(params.top_origin.Serialize());
if (params.is_cross_origin_iframe) {
ret.append(R"(,"crossOrigin":true)");
ret.append(R"(,"topOrigin":)");
ret.append(serialized_top_origin);
} else {
ret.append(R"(,"crossOrigin":false)");
}
if (params.payment_options &&
params.type == ClientDataRequestType::kPaymentGet) {
ret.append(R"(,"payment":{)");
ret.append(R"("rpId":)");
ret.append(ToJSONString(params.payment_rp));
ret.append(R"(,"topOrigin":)");
ret.append(serialized_top_origin);
if (params.payment_options->payee_name.has_value()) {
ret.append(R"(,"payeeName":)");
ret.append(ToJSONString(params.payment_options->payee_name.value()));
}
if (params.payment_options->payee_origin.has_value()) {
ret.append(R"(,"payeeOrigin":)");
ret.append(
ToJSONString(params.payment_options->payee_origin->Serialize()));
}
ret.append(R"(,"total":{)");
ret.append(R"("value":)");
ret.append(ToJSONString(params.payment_options->total->value));
ret.append(R"(,"currency":)");
ret.append(ToJSONString(params.payment_options->total->currency));
ret.append(R"(},"instrument":{)");
ret.append(R"("icon":)");
ret.append(ToJSONString(params.payment_options->instrument->icon.spec()));
ret.append(R"(,"displayName":)");
ret.append(ToJSONString(params.payment_options->instrument->display_name));
ret.append("}");
if (params.payment_options->browser_bound_public_key.has_value()) {
ret.append(R"(,"browserBoundPublicKey":)");
ret.append(ToJSONString(Base64UrlEncodeOmitPadding(
*params.payment_options->browser_bound_public_key)));
}
ret.append("}");
} else if (params.payment_options &&
params.payment_options->browser_bound_public_key.has_value() &&
params.type == ClientDataRequestType::kWebAuthnCreate) {
ret.append(R"(","payment":{"browserBoundPublicKey":)");
ret.append(ToJSONString(Base64UrlEncodeOmitPadding(
*params.payment_options->browser_bound_public_key)));
ret.append("}");
}
if (base::RandDouble() < 0.2) {
// An extra key is sometimes added to ensure that RPs do not make
// unreasonably specific assumptions about the clientData JSON. This is
// done in the fashion of
// https://tools.ietf.org/html/draft-ietf-tls-grease
ret.append(R"(,"other_keys_can_be_added_here":")");
ret.append(
"do not compare clientDataJSON against a template. See "
"https://goo.gl/yabPex\"");
}
ret.append("}");
return ret;
}
} // namespace content
|
