1/*
2 * Copyright (C) 2017 Apple Inc. All rights reserved.
3 * Copyright (C) 2017 Metrological Group B.V.
4 * Copyright (C) 2017 Igalia S.L.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
16 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
17 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
18 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
19 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
20 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
21 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
22 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
23 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
24 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
25 * THE POSSIBILITY OF SUCH DAMAGE.
26 */
27
28#include "config.h"
29#include "CryptoAlgorithmECDSA.h"
30
31#if ENABLE(WEB_CRYPTO)
32
33#include "CryptoAlgorithmEcdsaParams.h"
34#include "CryptoKeyEC.h"
35#include "GCryptUtilities.h"
36#include <pal/crypto/CryptoDigest.h>
37
38namespace WebCore {
39
40static bool extractECDSASignatureInteger(Vector<uint8_t>& signature, gcry_sexp_t signatureSexp, const char* integerName, size_t keySizeInBytes)
41{
42 // Retrieve byte data of the specified integer.
43 PAL::GCrypt::Handle<gcry_sexp_t> integerSexp(gcry_sexp_find_token(signatureSexp, integerName, 0));
44 if (!integerSexp)
45 return false;
46
47 auto integerData = mpiData(integerSexp);
48 if (!integerData)
49 return false;
50
51 size_t dataSize = integerData->size();
52 if (dataSize >= keySizeInBytes) {
53 // Append the last `keySizeInBytes` bytes of the data Vector, if available.
54 signature.append(&integerData->at(dataSize - keySizeInBytes), keySizeInBytes);
55 } else {
56 // If not, prefix the binary data with zero bytes.
57 for (size_t paddingSize = keySizeInBytes - dataSize; paddingSize > 0; --paddingSize)
58 signature.uncheckedAppend(0x00);
59 signature.appendVector(*integerData);
60 }
61
62 return true;
63}
64
65static Optional<Vector<uint8_t>> gcryptSign(gcry_sexp_t keySexp, const Vector<uint8_t>& data, CryptoAlgorithmIdentifier hashAlgorithmIdentifier, size_t keySizeInBytes)
66{
67 // Perform digest operation with the specified algorithm on the given data.
68 Vector<uint8_t> dataHash;
69 {
70 auto digestAlgorithm = hashCryptoDigestAlgorithm(hashAlgorithmIdentifier);
71 if (!digestAlgorithm)
72 return WTF::nullopt;
73
74 auto digest = PAL::CryptoDigest::create(*digestAlgorithm);
75 if (!digest)
76 return WTF::nullopt;
77
78 digest->addBytes(data.data(), data.size());
79 dataHash = digest->computeHash();
80 }
81
82 // Construct the data s-expression that contains raw hashed data.
83 PAL::GCrypt::Handle<gcry_sexp_t> dataSexp;
84 {
85 auto shaAlgorithm = hashAlgorithmName(hashAlgorithmIdentifier);
86 if (!shaAlgorithm)
87 return WTF::nullopt;
88
89 gcry_error_t error = gcry_sexp_build(&dataSexp, nullptr, "(data(flags raw)(hash %s %b))",
90 *shaAlgorithm, dataHash.size(), dataHash.data());
91 if (error != GPG_ERR_NO_ERROR) {
92 PAL::GCrypt::logError(error);
93 return WTF::nullopt;
94 }
95 }
96
97 // Perform the PK signing, retrieving a sig-val s-expression of the following form:
98 // (sig-val
99 // (dsa
100 // (r r-mpi)
101 // (s s-mpi)))
102 PAL::GCrypt::Handle<gcry_sexp_t> signatureSexp;
103 gcry_error_t error = gcry_pk_sign(&signatureSexp, dataSexp, keySexp);
104 if (error != GPG_ERR_NO_ERROR) {
105 PAL::GCrypt::logError(error);
106 return WTF::nullopt;
107 }
108
109 // Retrieve MPI data of the resulting r and s integers. They are concatenated into
110 // a single buffer, properly accounting for integers that don't match the key in size.
111 Vector<uint8_t> signature;
112 signature.reserveInitialCapacity(keySizeInBytes * 2);
113
114 if (!extractECDSASignatureInteger(signature, signatureSexp, "r", keySizeInBytes)
115 || !extractECDSASignatureInteger(signature, signatureSexp, "s", keySizeInBytes))
116 return WTF::nullopt;
117
118 return signature;
119}
120
121static Optional<bool> gcryptVerify(gcry_sexp_t keySexp, const Vector<uint8_t>& signature, const Vector<uint8_t>& data, CryptoAlgorithmIdentifier hashAlgorithmIdentifier, size_t keySizeInBytes)
122{
123 // Bail if the signature size isn't double the key size (i.e. concatenated r and s components).
124 if (signature.size() != keySizeInBytes * 2)
125 return false;
126
127 // Perform digest operation with the specified algorithm on the given data.
128 Vector<uint8_t> dataHash;
129 {
130 auto digestAlgorithm = hashCryptoDigestAlgorithm(hashAlgorithmIdentifier);
131 if (!digestAlgorithm)
132 return WTF::nullopt;
133
134 auto digest = PAL::CryptoDigest::create(*digestAlgorithm);
135 if (!digest)
136 return WTF::nullopt;
137
138 digest->addBytes(data.data(), data.size());
139 dataHash = digest->computeHash();
140 }
141
142 // Construct the sig-val s-expression, extracting the r and s components from the signature vector.
143 PAL::GCrypt::Handle<gcry_sexp_t> signatureSexp;
144 gcry_error_t error = gcry_sexp_build(&signatureSexp, nullptr, "(sig-val(ecdsa(r %b)(s %b)))",
145 keySizeInBytes, signature.data(), keySizeInBytes, signature.data() + keySizeInBytes);
146 if (error != GPG_ERR_NO_ERROR) {
147 PAL::GCrypt::logError(error);
148 return WTF::nullopt;
149 }
150
151 // Construct the data s-expression that contains raw hashed data.
152 PAL::GCrypt::Handle<gcry_sexp_t> dataSexp;
153 {
154 auto shaAlgorithm = hashAlgorithmName(hashAlgorithmIdentifier);
155 if (!shaAlgorithm)
156 return WTF::nullopt;
157
158 error = gcry_sexp_build(&dataSexp, nullptr, "(data(flags raw)(hash %s %b))",
159 *shaAlgorithm, dataHash.size(), dataHash.data());
160 if (error != GPG_ERR_NO_ERROR) {
161 PAL::GCrypt::logError(error);
162 return WTF::nullopt;
163 }
164 }
165
166 // Perform the PK verification. We report success if there's no error returned, or
167 // a failure in any other case. OperationError should not be returned at this point,
168 // avoiding spilling information about the exact cause of verification failure.
169 error = gcry_pk_verify(signatureSexp, dataSexp, keySexp);
170 return { error == GPG_ERR_NO_ERROR };
171}
172
173ExceptionOr<Vector<uint8_t>> CryptoAlgorithmECDSA::platformSign(const CryptoAlgorithmEcdsaParams& parameters, const CryptoKeyEC& key, const Vector<uint8_t>& data)
174{
175 auto output = gcryptSign(key.platformKey(), data, parameters.hashIdentifier, (key.keySizeInBits() + 7) / 8);
176 if (!output)
177 return Exception { OperationError };
178 return WTFMove(*output);
179}
180
181ExceptionOr<bool> CryptoAlgorithmECDSA::platformVerify(const CryptoAlgorithmEcdsaParams& parameters, const CryptoKeyEC& key, const Vector<uint8_t>& signature, const Vector<uint8_t>& data)
182{
183 auto output = gcryptVerify(key.platformKey(), signature, data, parameters.hashIdentifier, (key.keySizeInBits() + 7)/ 8);
184 if (!output)
185 return Exception { OperationError };
186 return WTFMove(*output);
187}
188
189} // namespace WebCore
190
191#endif // ENABLE(WEB_CRYPTO)
192