Line data Source code
1 : /*
2 : *
3 : * Copyright (c) 2020-2023 Project CHIP Authors
4 : *
5 : * Licensed under the Apache License, Version 2.0 (the "License");
6 : * you may not use this file except in compliance with the License.
7 : * You may obtain a copy of the License at
8 : *
9 : * http://www.apache.org/licenses/LICENSE-2.0
10 : *
11 : * Unless required by applicable law or agreed to in writing, software
12 : * distributed under the License is distributed on an "AS IS" BASIS,
13 : * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 : * See the License for the specific language governing permissions and
15 : * limitations under the License.
16 : */
17 :
18 : /**
19 : * @file
20 : * Header that exposes the platform agnostic CHIP crypto primitives
21 : */
22 :
23 : #pragma once
24 :
25 : #if CHIP_HAVE_CONFIG_H
26 : #include <crypto/CryptoBuildConfig.h>
27 : #endif // CHIP_HAVE_CONFIG_H
28 :
29 : #include <system/SystemConfig.h>
30 :
31 : #include <lib/core/CHIPError.h>
32 : #include <lib/core/CHIPVendorIdentifiers.hpp>
33 : #include <lib/core/DataModelTypes.h>
34 : #include <lib/core/Optional.h>
35 : #include <lib/support/Base64.h>
36 : #include <lib/support/BufferReader.h>
37 : #include <lib/support/CodeUtils.h>
38 : #include <lib/support/SafePointerCast.h>
39 : #include <lib/support/Span.h>
40 : #include <lib/support/StringBuilder.h>
41 :
42 : #include <stddef.h>
43 : #include <string.h>
44 :
45 : namespace chip {
46 : namespace Crypto {
47 :
48 : inline constexpr size_t kMax_x509_Certificate_Length = 600;
49 :
50 : inline constexpr size_t kP256_FE_Length = 32;
51 : inline constexpr size_t kP256_ECDSA_Signature_Length_Raw = (2 * kP256_FE_Length);
52 : inline constexpr size_t kP256_Point_Length = (2 * kP256_FE_Length + 1);
53 : inline constexpr size_t kSHA256_Hash_Length = 32;
54 : inline constexpr size_t kSHA1_Hash_Length = 20;
55 : inline constexpr size_t kSubjectKeyIdentifierLength = kSHA1_Hash_Length;
56 : inline constexpr size_t kAuthorityKeyIdentifierLength = kSHA1_Hash_Length;
57 : inline constexpr size_t kMaxCertificateSerialNumberLength = 20;
58 : inline constexpr size_t kMaxCertificateDistinguishedNameLength = 200;
59 : inline constexpr size_t kMaxCRLDistributionPointURLLength = 100;
60 :
61 : inline constexpr char kValidCDPURIHttpPrefix[] = "http://";
62 : inline constexpr char kValidCDPURIHttpsPrefix[] = "https://";
63 :
64 : inline constexpr size_t CHIP_CRYPTO_GROUP_SIZE_BYTES = kP256_FE_Length;
65 : inline constexpr size_t CHIP_CRYPTO_PUBLIC_KEY_SIZE_BYTES = kP256_Point_Length;
66 :
67 : inline constexpr size_t CHIP_CRYPTO_AEAD_MIC_LENGTH_BYTES = 16;
68 : inline constexpr size_t CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES = 16;
69 :
70 : inline constexpr size_t kMax_ECDH_Secret_Length = kP256_FE_Length;
71 : inline constexpr size_t kMax_ECDSA_Signature_Length = kP256_ECDSA_Signature_Length_Raw;
72 : inline constexpr size_t kMAX_FE_Length = kP256_FE_Length;
73 : inline constexpr size_t kMAX_Point_Length = kP256_Point_Length;
74 : inline constexpr size_t kMAX_Hash_Length = kSHA256_Hash_Length;
75 :
76 : // Minimum required CSR length buffer length is relatively small since it's a single
77 : // P256 key and no metadata/extensions are expected to be honored by the CA.
78 : inline constexpr size_t kMIN_CSR_Buffer_Size = 255;
79 :
80 : [[deprecated("This constant is no longer used by common code and should be replaced by kMIN_CSR_Buffer_Size. Checks that a CSR is "
81 : "<= kMAX_CSR_Buffer_size must be updated. This remains to keep valid buffers working from previous public API "
82 : "usage.")]] constexpr size_t kMAX_CSR_Buffer_Size = 255;
83 :
84 : inline constexpr size_t CHIP_CRYPTO_HASH_LEN_BYTES = kSHA256_Hash_Length;
85 :
86 : inline constexpr size_t kSpake2p_Min_PBKDF_Salt_Length = 16;
87 : inline constexpr size_t kSpake2p_Max_PBKDF_Salt_Length = 32;
88 : inline constexpr uint32_t kSpake2p_Min_PBKDF_Iterations = 1000;
89 : inline constexpr uint32_t kSpake2p_Max_PBKDF_Iterations = 100000;
90 :
91 : inline constexpr size_t kP256_PrivateKey_Length = CHIP_CRYPTO_GROUP_SIZE_BYTES;
92 : inline constexpr size_t kP256_PublicKey_Length = CHIP_CRYPTO_PUBLIC_KEY_SIZE_BYTES;
93 :
94 : inline constexpr size_t kAES_CCM128_Key_Length = 128u / 8u;
95 : inline constexpr size_t kAES_CCM128_Block_Length = kAES_CCM128_Key_Length;
96 : inline constexpr size_t kAES_CCM128_Nonce_Length = 13;
97 : inline constexpr size_t kAES_CCM128_Tag_Length = 16;
98 : inline constexpr size_t kHMAC_CCM128_Key_Length = 128u / 8u;
99 :
100 : inline constexpr size_t CHIP_CRYPTO_AEAD_NONCE_LENGTH_BYTES = kAES_CCM128_Nonce_Length;
101 :
102 : /* These sizes are hardcoded here to remove header dependency on underlying crypto library
103 : * in a public interface file. The validity of these sizes is verified by static_assert in
104 : * the implementation files.
105 : */
106 : inline constexpr size_t kMAX_Spake2p_Context_Size = 1024;
107 : inline constexpr size_t kMAX_P256Keypair_Context_Size = 512;
108 :
109 : inline constexpr size_t kEmitDerIntegerWithoutTagOverhead = 1; // 1 sign stuffer
110 : inline constexpr size_t kEmitDerIntegerOverhead = 3; // Tag + Length byte + 1 sign stuffer
111 :
112 : inline constexpr size_t kMAX_Hash_SHA256_Context_Size = CHIP_CONFIG_SHA256_CONTEXT_SIZE;
113 :
114 : inline constexpr size_t kSpake2p_WS_Length = kP256_FE_Length + 8;
115 : inline constexpr size_t kSpake2p_VerifierSerialized_Length = kP256_FE_Length + kP256_Point_Length;
116 :
117 : inline constexpr char kVIDPrefixForCNEncoding[] = "Mvid:";
118 : inline constexpr char kPIDPrefixForCNEncoding[] = "Mpid:";
119 : inline constexpr size_t kVIDandPIDHexLength = sizeof(uint16_t) * 2;
120 : inline constexpr size_t kMax_CommonNameAttr_Length = 64;
121 :
122 : enum class FabricBindingVersion : uint8_t
123 : {
124 : kVersion1 = 0x01 // Initial version using version 1.0 of the Matter Cryptographic Primitives.
125 : };
126 :
127 : // VidVerificationStatementVersion is on purpose different and non-overlapping with FabricBindingVersion.
128 : enum class VidVerificationStatementVersion : uint8_t
129 : {
130 : kVersion1 = 0x21 // Initial version using version 1.0 of the Matter Cryptographic Primitives.
131 : };
132 :
133 : inline constexpr uint8_t kFabricBindingVersionV1 = 1u;
134 :
135 : inline constexpr size_t kVendorIdVerificationClientChallengeSize = 32u;
136 :
137 : // VIDVerificationStatement := statement_version || vid_verification_signer_skid || vid_verification_statement_signature
138 : inline constexpr size_t kVendorIdVerificationStatementV1Size =
139 : sizeof(uint8_t) + kSubjectKeyIdentifierLength + kP256_ECDSA_Signature_Length_Raw;
140 : static_assert(
141 : kVendorIdVerificationStatementV1Size == 85,
142 : "Expected size of VendorIdVerificationStatement version 1 was computed incorrectly due to changes of fundamental constants");
143 :
144 : // vendor_fabric_binding_message := fabric_binding_version (1 byte) || root_public_key || fabric_id || vendor_id
145 : inline constexpr size_t kVendorFabricBindingMessageV1Size =
146 : sizeof(uint8_t) + CHIP_CRYPTO_PUBLIC_KEY_SIZE_BYTES + sizeof(uint64_t) + sizeof(uint16_t);
147 : static_assert(
148 : kVendorFabricBindingMessageV1Size == 76,
149 : "Expected size of VendorFabricBindingMessage version 1 was computed incorrectly due to changes of fundamental constants");
150 :
151 : // vendor_id_verification_tbs := fabric_binding_version || client_challenge || attestation_challenge || fabric_index ||
152 : // vendor_fabric_binding_message || <vid_verification_statement>
153 : inline constexpr size_t kVendorIdVerificationTbsV1MaxSize = sizeof(uint8_t) + kVendorIdVerificationClientChallengeSize +
154 : CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES + sizeof(uint8_t) + kVendorFabricBindingMessageV1Size +
155 : kVendorIdVerificationStatementV1Size;
156 :
157 : /*
158 : * Overhead to encode a raw ECDSA signature in X9.62 format in ASN.1 DER
159 : *
160 : * Ecdsa-Sig-Value ::= SEQUENCE {
161 : * r INTEGER,
162 : * s INTEGER
163 : * }
164 : *
165 : * --> SEQUENCE, universal constructed tag (0x30), length over 2 bytes, up to 255 (to support future larger sizes up to 512 bits)
166 : * -> SEQ_OVERHEAD = 3 bytes
167 : * --> INTEGER, universal primitive tag (0x02), length over 1 byte, one extra byte worst case
168 : * over max for 0x00 when MSB is set.
169 : * -> INT_OVERHEAD = 3 bytes
170 : *
171 : * There is 1 sequence of 2 integers. Overhead is SEQ_OVERHEAD + (2 * INT_OVERHEAD) = 3 + (2 * 3) = 9.
172 : */
173 : inline constexpr size_t kMax_ECDSA_X9Dot62_Asn1_Overhead = 9;
174 : inline constexpr size_t kMax_ECDSA_Signature_Length_Der = kMax_ECDSA_Signature_Length + kMax_ECDSA_X9Dot62_Asn1_Overhead;
175 :
176 : static_assert(kMax_ECDH_Secret_Length >= kP256_FE_Length, "ECDH shared secret is too short for crypto suite");
177 : static_assert(kMax_ECDSA_Signature_Length >= kP256_ECDSA_Signature_Length_Raw,
178 : "ECDSA signature buffer length is too short for crypto suite");
179 :
180 : inline constexpr size_t kCompressedFabricIdentifierSize = 8;
181 :
182 : /**
183 : * Spake2+ parameters for P256
184 : * Defined in https://www.ietf.org/id/draft-bar-cfrg-spake2plus-01.html#name-ciphersuites
185 : */
186 : const uint8_t spake2p_M_p256[] = {
187 : 0x04, 0x88, 0x6e, 0x2f, 0x97, 0xac, 0xe4, 0x6e, 0x55, 0xba, 0x9d, 0xd7, 0x24, 0x25, 0x79, 0xf2, 0x99,
188 : 0x3b, 0x64, 0xe1, 0x6e, 0xf3, 0xdc, 0xab, 0x95, 0xaf, 0xd4, 0x97, 0x33, 0x3d, 0x8f, 0xa1, 0x2f, 0x5f,
189 : 0xf3, 0x55, 0x16, 0x3e, 0x43, 0xce, 0x22, 0x4e, 0x0b, 0x0e, 0x65, 0xff, 0x02, 0xac, 0x8e, 0x5c, 0x7b,
190 : 0xe0, 0x94, 0x19, 0xc7, 0x85, 0xe0, 0xca, 0x54, 0x7d, 0x55, 0xa1, 0x2e, 0x2d, 0x20,
191 : };
192 : const uint8_t spake2p_N_p256[] = {
193 : 0x04, 0xd8, 0xbb, 0xd6, 0xc6, 0x39, 0xc6, 0x29, 0x37, 0xb0, 0x4d, 0x99, 0x7f, 0x38, 0xc3, 0x77, 0x07,
194 : 0x19, 0xc6, 0x29, 0xd7, 0x01, 0x4d, 0x49, 0xa2, 0x4b, 0x4f, 0x98, 0xba, 0xa1, 0x29, 0x2b, 0x49, 0x07,
195 : 0xd6, 0x0a, 0xa6, 0xbf, 0xad, 0xe4, 0x50, 0x08, 0xa6, 0x36, 0x33, 0x7f, 0x51, 0x68, 0xc6, 0x4d, 0x9b,
196 : 0xd3, 0x60, 0x34, 0x80, 0x8c, 0xd5, 0x64, 0x49, 0x0b, 0x1e, 0x65, 0x6e, 0xdb, 0xe7,
197 : };
198 :
199 : /**
200 : * Spake2+ state machine to ensure proper execution of the protocol.
201 : */
202 : enum class CHIP_SPAKE2P_STATE : uint8_t
203 : {
204 : PREINIT = 0, // Before any initialization
205 : INIT, // First initialization
206 : STARTED, // Prover & Verifier starts
207 : R1, // Round one complete
208 : R2, // Round two complete
209 : KC, // Key confirmation complete
210 : };
211 :
212 : /**
213 : * Spake2+ role.
214 : */
215 : enum class CHIP_SPAKE2P_ROLE : uint8_t
216 : {
217 : VERIFIER = 0, // Accessory
218 : PROVER = 1, // Commissioner
219 : };
220 :
221 : enum class SupportedECPKeyTypes : uint8_t
222 : {
223 : ECP256R1 = 0,
224 : };
225 :
226 : enum class ECPKeyTarget : uint8_t
227 : {
228 : ECDH = 0,
229 : ECDSA = 1,
230 : };
231 :
232 : /** @brief Safely clears the first `len` bytes of memory area `buf`.
233 : * @param buf Pointer to a memory buffer holding secret data that must be cleared.
234 : * @param len Specifies secret data size in bytes.
235 : **/
236 : void ClearSecretData(uint8_t * buf, size_t len);
237 :
238 : /**
239 : * Helper for clearing a C array which auto-deduces the size.
240 : */
241 : template <size_t N>
242 413666 : void ClearSecretData(uint8_t (&buf)[N])
243 : {
244 413666 : ClearSecretData(buf, N);
245 413666 : }
246 :
247 : /**
248 : * @brief Constant-time buffer comparison
249 : *
250 : * This function implements constant time memcmp. It's good practice
251 : * to use constant time functions for cryptographic functions.
252 : *
253 : * @param a Pointer to first buffer
254 : * @param b Pointer to Second buffer
255 : * @param n Number of bytes to compare
256 : * @return true if `n` first bytes of both buffers are equal, false otherwise
257 : */
258 : bool IsBufferContentEqualConstantTime(const void * a, const void * b, size_t n);
259 :
260 : template <typename Sig>
261 : class ECPKey
262 : {
263 : protected:
264 : // This base type can't be copied / assigned directly.
265 : // Sub-types should be either uncopyable or final.
266 90 : ECPKey() = default;
267 : ECPKey(const ECPKey &) = default;
268 1628 : ECPKey & operator=(const ECPKey &) = default;
269 :
270 : public:
271 910 : virtual ~ECPKey() = default;
272 :
273 : virtual SupportedECPKeyTypes Type() const = 0;
274 : virtual size_t Length() const = 0;
275 : virtual bool IsUncompressed() const = 0;
276 : virtual operator const uint8_t *() const = 0;
277 : virtual operator uint8_t *() = 0;
278 : virtual const uint8_t * ConstBytes() const = 0;
279 : virtual uint8_t * Bytes() = 0;
280 :
281 0 : virtual bool Matches(const ECPKey<Sig> & other) const
282 : {
283 0 : return (this->Length() == other.Length()) &&
284 0 : IsBufferContentEqualConstantTime(this->ConstBytes(), other.ConstBytes(), this->Length());
285 : }
286 :
287 : virtual CHIP_ERROR ECDSA_validate_msg_signature(const uint8_t * msg, const size_t msg_length, const Sig & signature) const = 0;
288 : virtual CHIP_ERROR ECDSA_validate_hash_signature(const uint8_t * hash, const size_t hash_length,
289 : const Sig & signature) const = 0;
290 : };
291 :
292 : /**
293 : * @brief Helper class for holding sensitive data that should be erased from memory after use.
294 : *
295 : * The sensitive data buffer is a variable-length, fixed-capacity buffer class that securely erases
296 : * the contents of a buffer when the buffer is destroyed.
297 : */
298 : template <size_t kCapacity>
299 : class SensitiveDataBuffer
300 : {
301 : public:
302 3693 : ~SensitiveDataBuffer()
303 : {
304 : // Sanitize after use
305 3693 : ClearSecretData(mBytes);
306 3693 : }
307 3692 : SensitiveDataBuffer() {}
308 1 : SensitiveDataBuffer(const SensitiveDataBuffer & other) { *this = other; }
309 1 : SensitiveDataBuffer & operator=(const SensitiveDataBuffer & other)
310 : {
311 : // Guard self assignment
312 1 : if (this == &other)
313 0 : return *this;
314 :
315 1 : ClearSecretData(mBytes);
316 1 : SetLength(other.Length());
317 1 : ::memcpy(Bytes(), other.ConstBytes(), other.Length());
318 1 : return *this;
319 : }
320 :
321 : /**
322 : * @brief Set current length of the buffer
323 : * @return Error if new length is exceeds capacity of the buffer
324 : */
325 3565 : CHIP_ERROR SetLength(size_t length)
326 : {
327 3565 : VerifyOrReturnError(length <= kCapacity, CHIP_ERROR_INVALID_ARGUMENT);
328 3565 : mLength = length;
329 3565 : return CHIP_NO_ERROR;
330 : }
331 :
332 : /**
333 : * @brief Returns current length of the buffer
334 : */
335 3769 : size_t Length() const { return mLength; }
336 :
337 : /**
338 : * @brief Returns non-const pointer to start of the underlying buffer
339 : */
340 3956 : uint8_t * Bytes() { return &mBytes[0]; }
341 :
342 : /**
343 : * @brief Returns const pointer to start of the underlying buffer
344 : */
345 6302 : const uint8_t * ConstBytes() const { return &mBytes[0]; }
346 :
347 : /**
348 : * @brief Constructs span from the underlying buffer
349 : */
350 21 : ByteSpan Span() const { return ByteSpan(ConstBytes(), Length()); }
351 :
352 : /**
353 : * @brief Returns capacity of the buffer
354 : */
355 1489 : static constexpr size_t Capacity() { return kCapacity; }
356 :
357 : private:
358 : uint8_t mBytes[kCapacity];
359 : size_t mLength = 0;
360 : };
361 :
362 : /**
363 : * @brief Helper class for holding fixed-sized sensitive data that should be erased from memory after use.
364 : *
365 : * The sensitive data buffer is a fixed-length, fixed-capacity buffer class that securely erases
366 : * the contents of a buffer when the buffer is destroyed.
367 : */
368 : template <size_t kCapacity>
369 : class SensitiveDataFixedBuffer
370 : {
371 : public:
372 : SensitiveDataFixedBuffer() = default;
373 :
374 : constexpr explicit SensitiveDataFixedBuffer(const uint8_t (&rawValue)[kCapacity])
375 : {
376 : memcpy(&mBytes[0], &rawValue[0], kCapacity);
377 : }
378 :
379 0 : constexpr explicit SensitiveDataFixedBuffer(const FixedByteSpan<kCapacity> & value)
380 : {
381 0 : memcpy(&mBytes[0], value.data(), kCapacity);
382 0 : }
383 :
384 135355 : ~SensitiveDataFixedBuffer()
385 : {
386 : // Sanitize after use
387 135355 : ClearSecretData(mBytes);
388 135355 : }
389 :
390 : /**
391 : * @brief Returns fixed length of the buffer
392 : */
393 : constexpr size_t Length() const { return kCapacity; }
394 :
395 : /**
396 : * @brief Returns non-const pointer to start of the underlying buffer
397 : */
398 1573 : uint8_t * Bytes() { return &mBytes[0]; }
399 :
400 : /**
401 : * @brief Returns const pointer to start of the underlying buffer
402 : */
403 : const uint8_t * ConstBytes() const { return &mBytes[0]; }
404 :
405 : /**
406 : * @brief Constructs fixed span from the underlying buffer
407 : */
408 0 : FixedByteSpan<kCapacity> Span() const { return FixedByteSpan<kCapacity>(mBytes); }
409 :
410 : /**
411 : * @brief Returns capacity of the buffer
412 : */
413 1558 : static constexpr size_t Capacity() { return kCapacity; }
414 :
415 : private:
416 : uint8_t mBytes[kCapacity];
417 : };
418 :
419 : using P256ECDSASignature = SensitiveDataBuffer<kMax_ECDSA_Signature_Length>;
420 : using P256ECDHDerivedSecret = SensitiveDataBuffer<kMax_ECDH_Secret_Length>;
421 :
422 : using IdentityProtectionKey = SensitiveDataFixedBuffer<CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES>;
423 : using IdentityProtectionKeySpan = FixedByteSpan<Crypto::CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES>;
424 :
425 : using AttestationChallenge = SensitiveDataFixedBuffer<CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES>;
426 :
427 : class P256PublicKey final // final due to being copyable
428 : : public ECPKey<P256ECDSASignature>
429 : {
430 : public:
431 90 : P256PublicKey() = default;
432 :
433 : template <size_t N>
434 : constexpr P256PublicKey(const uint8_t (&raw_value)[N])
435 : {
436 : static_assert(N == kP256_PublicKey_Length, "Can only array-initialize from proper bounds");
437 : memcpy(&bytes[0], &raw_value[0], N);
438 : }
439 :
440 : template <size_t N>
441 744 : constexpr P256PublicKey(const FixedByteSpan<N> & value)
442 744 : {
443 : static_assert(N == kP256_PublicKey_Length, "Can only initialize from proper sized byte span");
444 744 : memcpy(&bytes[0], value.data(), N);
445 744 : }
446 :
447 : template <size_t N>
448 946 : P256PublicKey & operator=(const FixedByteSpan<N> & value)
449 : {
450 : static_assert(N == kP256_PublicKey_Length, "Can only initialize from proper sized byte span");
451 946 : memcpy(&bytes[0], value.data(), N);
452 946 : return *this;
453 : }
454 :
455 4267 : SupportedECPKeyTypes Type() const override { return SupportedECPKeyTypes::ECP256R1; }
456 14552 : size_t Length() const override { return kP256_PublicKey_Length; }
457 6354 : operator uint8_t *() override { return bytes; }
458 2674 : operator const uint8_t *() const override { return bytes; }
459 3210 : const uint8_t * ConstBytes() const override { return &bytes[0]; }
460 20 : uint8_t * Bytes() override { return &bytes[0]; }
461 814 : bool IsUncompressed() const override
462 : {
463 814 : constexpr uint8_t kUncompressedPointMarker = 0x04;
464 : // SEC1 definition of an uncompressed point is (0x04 || X || Y) where X and Y are
465 : // raw zero-padded big-endian large integers of the group size.
466 814 : return (Length() == ((kP256_FE_Length * 2) + 1)) && (ConstBytes()[0] == kUncompressedPointMarker);
467 : }
468 :
469 : CHIP_ERROR ECDSA_validate_msg_signature(const uint8_t * msg, size_t msg_length,
470 : const P256ECDSASignature & signature) const override;
471 : CHIP_ERROR ECDSA_validate_hash_signature(const uint8_t * hash, size_t hash_length,
472 : const P256ECDSASignature & signature) const override;
473 :
474 : private:
475 : uint8_t bytes[kP256_PublicKey_Length];
476 : };
477 :
478 : template <typename PK, typename Secret, typename Sig>
479 : class ECPKeypair
480 : {
481 : protected:
482 : // This base type can't be copied / assigned directly.
483 : // Sub-types should be either uncopyable or final.
484 1429 : ECPKeypair() = default;
485 : ECPKeypair(const ECPKeypair &) = default;
486 : ECPKeypair & operator=(const ECPKeypair &) = default;
487 :
488 : public:
489 1770 : virtual ~ECPKeypair() = default;
490 :
491 : /** @brief Generate a new Certificate Signing Request (CSR).
492 : * @param csr Newly generated CSR in DER format
493 : * @param csr_length The caller provides the length of input buffer (csr). The function returns the actual length of generated
494 : *CSR.
495 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
496 : **/
497 : virtual CHIP_ERROR NewCertificateSigningRequest(uint8_t * csr, size_t & csr_length) const = 0;
498 :
499 : /**
500 : * @brief A function to sign a msg using ECDSA
501 : * @param msg Message that needs to be signed
502 : * @param msg_length Length of message
503 : * @param out_signature Buffer that will hold the output signature. The signature consists of: 2 EC elements (r and s),
504 : * in raw <r,s> point form (see SEC1).
505 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
506 : **/
507 : virtual CHIP_ERROR ECDSA_sign_msg(const uint8_t * msg, size_t msg_length, Sig & out_signature) const = 0;
508 :
509 : /** @brief A function to derive a shared secret using ECDH
510 : * @param remote_public_key Public key of remote peer with which we are trying to establish secure channel. remote_public_key is
511 : * ASN.1 DER encoded as padded big-endian field elements as described in SEC 1: Elliptic Curve Cryptography
512 : * [https://www.secg.org/sec1-v2.pdf]
513 : * @param out_secret Buffer to write out secret into. This is a byte array representing the x coordinate of the shared secret.
514 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
515 : **/
516 : virtual CHIP_ERROR ECDH_derive_secret(const PK & remote_public_key, Secret & out_secret) const = 0;
517 :
518 : virtual const PK & Pubkey() const = 0;
519 : };
520 :
521 : struct alignas(size_t) P256KeypairContext
522 : {
523 : uint8_t mBytes[kMAX_P256Keypair_Context_Size];
524 : };
525 :
526 : /**
527 : * A serialized P256 key pair is the concatenation of the public and private keys, in that order.
528 : */
529 : using P256SerializedKeypair = SensitiveDataBuffer<kP256_PublicKey_Length + kP256_PrivateKey_Length>;
530 :
531 : class P256KeypairBase : public ECPKeypair<P256PublicKey, P256ECDHDerivedSecret, P256ECDSASignature>
532 : {
533 : protected:
534 : // This base type can't be copied / assigned directly.
535 : // Sub-types should be either uncopyable or final.
536 1429 : P256KeypairBase() = default;
537 : P256KeypairBase(const P256KeypairBase &) = default;
538 : P256KeypairBase & operator=(const P256KeypairBase &) = default;
539 :
540 : public:
541 : /**
542 : * @brief Initialize the keypair.
543 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
544 : **/
545 : virtual CHIP_ERROR Initialize(ECPKeyTarget key_target) = 0;
546 :
547 : /**
548 : * @brief Serialize the keypair.
549 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
550 : **/
551 : virtual CHIP_ERROR Serialize(P256SerializedKeypair & output) const = 0;
552 :
553 : /**
554 : * @brief Deserialize the keypair.
555 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
556 : **/
557 : virtual CHIP_ERROR Deserialize(P256SerializedKeypair & input) = 0;
558 : };
559 :
560 : class P256Keypair : public P256KeypairBase
561 : {
562 : public:
563 1429 : P256Keypair() = default;
564 : ~P256Keypair() override;
565 :
566 : // P256Keypair can't be copied / assigned.
567 : P256Keypair(const P256Keypair &) = delete;
568 : P256Keypair & operator=(const P256Keypair &) = delete;
569 :
570 : /**
571 : * @brief Initialize the keypair.
572 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
573 : **/
574 : CHIP_ERROR Initialize(ECPKeyTarget key_target) override;
575 :
576 : /**
577 : * @brief Serialize the keypair.
578 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
579 : **/
580 : CHIP_ERROR Serialize(P256SerializedKeypair & output) const override;
581 :
582 : /**
583 : * @brief Deserialize the keypair.
584 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
585 : **/
586 : CHIP_ERROR Deserialize(P256SerializedKeypair & input) override;
587 :
588 : /**
589 : * @brief Generate a new Certificate Signing Request (CSR).
590 : * @param csr Newly generated CSR in DER format
591 : * @param csr_length The caller provides the length of input buffer (csr). The function returns the actual length of generated
592 : *CSR.
593 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
594 : **/
595 : CHIP_ERROR NewCertificateSigningRequest(uint8_t * csr, size_t & csr_length) const override;
596 :
597 : /**
598 : * @brief A function to sign a msg using ECDSA
599 : * @param msg Message that needs to be signed
600 : * @param msg_length Length of message
601 : * @param out_signature Buffer that will hold the output signature. The signature consists of: 2 EC elements (r and s),
602 : * in raw <r,s> point form (see SEC1).
603 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
604 : **/
605 : CHIP_ERROR ECDSA_sign_msg(const uint8_t * msg, size_t msg_length, P256ECDSASignature & out_signature) const override;
606 :
607 : /**
608 : * @brief A function to derive a shared secret using ECDH
609 : *
610 : * This implements the CHIP_Crypto_ECDH(PrivateKey myPrivateKey, PublicKey theirPublicKey) cryptographic primitive
611 : * from the specification, using this class's private key from `mKeypair` as `myPrivateKey` and the remote
612 : * public key from `remote_public_key` as `theirPublicKey`.
613 : *
614 : * @param remote_public_key Public key of remote peer with which we are trying to establish secure channel. remote_public_key is
615 : * ASN.1 DER encoded as padded big-endian field elements as described in SEC 1: Elliptic Curve Cryptography
616 : * [https://www.secg.org/sec1-v2.pdf]
617 : * @param out_secret Buffer to write out secret into. This is a byte array representing the x coordinate of the shared secret.
618 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
619 : **/
620 : CHIP_ERROR ECDH_derive_secret(const P256PublicKey & remote_public_key, P256ECDHDerivedSecret & out_secret) const override;
621 :
622 : /** @brief Return public key for the keypair.
623 : **/
624 822 : const P256PublicKey & Pubkey() const override { return mPublicKey; }
625 :
626 : #if CHIP_WITH_NLFAULTINJECTION
627 0 : P256PublicKey & TestOnlyMutablePubkey() { return mPublicKey; }
628 : #endif
629 :
630 : /** Release resources associated with this key pair */
631 : void Clear();
632 :
633 : protected:
634 : #if CHIP_WITH_NLFAULTINJECTION
635 : mutable P256PublicKey mPublicKey;
636 : #else
637 : P256PublicKey mPublicKey;
638 : #endif
639 : // P256PublicKey mPublicKey;
640 : mutable P256KeypairContext mKeypair;
641 : bool mInitialized = false;
642 : };
643 :
644 : /**
645 : * @brief Platform-specific symmetric key handle
646 : *
647 : * The class represents a key used by the Matter stack either in the form of raw key material or key
648 : * reference, depending on the platform. To achieve that, it contains an opaque context that can be
649 : * cast to a concrete representation used by the given platform.
650 : *
651 : * @note SymmetricKeyHandle is an abstract class to force child classes for each key handle type.
652 : * SymmetricKeyHandle class implements all the necessary components for handles.
653 : */
654 : template <size_t ContextSize>
655 : class SymmetricKeyHandle
656 : {
657 : public:
658 : SymmetricKeyHandle(const SymmetricKeyHandle &) = delete;
659 : SymmetricKeyHandle(SymmetricKeyHandle &&) = delete;
660 : void operator=(const SymmetricKeyHandle &) = delete;
661 : void operator=(SymmetricKeyHandle &&) = delete;
662 :
663 : /**
664 : * @brief Get internal context cast to the desired key representation
665 : */
666 : template <class T>
667 30432 : const T & As() const
668 : {
669 30432 : return *SafePointerCast<const T *>(&mContext);
670 : }
671 :
672 : /**
673 : * @brief Get internal context cast to the desired, mutable key representation
674 : */
675 : template <class T>
676 7466 : T & AsMutable()
677 : {
678 7466 : return *SafePointerCast<T *>(&mContext);
679 : }
680 :
681 : protected:
682 271234 : SymmetricKeyHandle() = default;
683 271234 : ~SymmetricKeyHandle() { ClearSecretData(mContext.mOpaque); }
684 :
685 : private:
686 : struct alignas(uintptr_t) OpaqueContext
687 : {
688 : uint8_t mOpaque[ContextSize] = {};
689 : } mContext;
690 : };
691 :
692 : using Symmetric128BitsKeyByteArray = uint8_t[CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES];
693 :
694 : /**
695 : * @brief Platform-specific 128-bit symmetric key handle
696 : */
697 : class Symmetric128BitsKeyHandle : public SymmetricKeyHandle<CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES>
698 : {
699 : };
700 :
701 : /**
702 : * @brief Platform-specific 128-bit AES key handle
703 : */
704 : class Aes128KeyHandle final : public Symmetric128BitsKeyHandle
705 : {
706 : };
707 :
708 : /**
709 : * @brief Platform-specific 128-bit HMAC key handle
710 : */
711 : class Hmac128KeyHandle final : public Symmetric128BitsKeyHandle
712 : {
713 : };
714 :
715 : /**
716 : * @brief Platform-specific HKDF key handle
717 : */
718 : class HkdfKeyHandle final : public SymmetricKeyHandle<CHIP_CONFIG_HKDF_KEY_HANDLE_CONTEXT_SIZE>
719 : {
720 : };
721 :
722 : /**
723 : * @brief Convert a raw ECDSA signature to ASN.1 signature (per X9.62) as used by TLS libraries.
724 : *
725 : * Errors are:
726 : * - CHIP_ERROR_INVALID_ARGUMENT on any argument being invalid (e.g. nullptr), wrong sizes,
727 : * wrong or unsupported format,
728 : * - CHIP_ERROR_BUFFER_TOO_SMALL on running out of space at runtime.
729 : * - CHIP_ERROR_INTERNAL on any unexpected processing error.
730 : *
731 : * @param[in] fe_length_bytes Field Element length in bytes (e.g. 32 for P256 curve)
732 : * @param[in] raw_sig Raw signature of <r,s> concatenated
733 : * @param[out] out_asn1_sig ASN.1 DER signature format output buffer. Size must have space for at least
734 : * kMax_ECDSA_X9Dot62_Asn1_Overhead. On CHIP_NO_ERROR, the out_asn1_sig buffer will be re-assigned
735 : * to have the correct size based on variable-length output.
736 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
737 : */
738 : CHIP_ERROR EcdsaRawSignatureToAsn1(size_t fe_length_bytes, const ByteSpan & raw_sig, MutableByteSpan & out_asn1_sig);
739 :
740 : /**
741 : * @brief Convert an ASN.1 DER signature (per X9.62) as used by TLS libraries to SEC1 raw format
742 : *
743 : * Errors are:
744 : * - CHIP_ERROR_INVALID_ARGUMENT on any argument being invalid (e.g. nullptr), wrong sizes,
745 : * wrong or unsupported format,
746 : * - CHIP_ERROR_BUFFER_TOO_SMALL on running out of space at runtime.
747 : * - CHIP_ERROR_INTERNAL on any unexpected processing error.
748 : *
749 : * @param[in] fe_length_bytes Field Element length in bytes (e.g. 32 for P256 curve)
750 : * @param[in] asn1_sig ASN.1 DER signature input
751 : * @param[out] out_raw_sig Raw signature of <r,s> concatenated format output buffer. Size must be at
752 : * least >= `2 * fe_length_bytes`. On CHIP_NO_ERROR, the out_raw_sig buffer will be re-assigned
753 : * to have the correct size (2 * fe_length_bytes).
754 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
755 : */
756 : CHIP_ERROR EcdsaAsn1SignatureToRaw(size_t fe_length_bytes, const ByteSpan & asn1_sig, MutableByteSpan & out_raw_sig);
757 :
758 : /**
759 : * @brief Utility to read a length field after a tag in a DER-encoded stream.
760 : * @param[in] reader Reader instance from which the input will be read
761 : * @param[out] length Length of the following element read from the stream
762 : * @return CHIP_ERROR_INVALID_ARGUMENT or CHIP_ERROR_BUFFER_TOO_SMALL on error, CHIP_NO_ERROR otherwise
763 : */
764 : CHIP_ERROR ReadDerLength(chip::Encoding::LittleEndian::Reader & reader, size_t & length);
765 :
766 : /**
767 : * @brief Utility to emit a DER-encoded INTEGER given a raw unsigned large integer
768 : * in big-endian order. The `out_der_integer` span is updated to reflect the final
769 : * variable length, including tag and length, and must have at least `kEmitDerIntegerOverhead`
770 : * extra space in addition to the `raw_integer.size()`.
771 : * @param[in] raw_integer Bytes of a large unsigned integer in big-endian, possibly including leading zeroes
772 : * @param[out] out_der_integer Buffer to receive the DER-encoded integer
773 : * @return Returns CHIP_ERROR_INVALID_ARGUMENT or CHIP_ERROR_BUFFER_TOO_SMALL on error, CHIP_NO_ERROR otherwise.
774 : */
775 : CHIP_ERROR ConvertIntegerRawToDer(const ByteSpan & raw_integer, MutableByteSpan & out_der_integer);
776 :
777 : /**
778 : * @brief Utility to emit a DER-encoded INTEGER given a raw unsigned large integer
779 : * in big-endian order. The `out_der_integer` span is updated to reflect the final
780 : * variable length, excluding tag and length, and must have at least `kEmitDerIntegerWithoutTagOverhead`
781 : * extra space in addition to the `raw_integer.size()`.
782 : * @param[in] raw_integer Bytes of a large unsigned integer in big-endian, possibly including leading zeroes
783 : * @param[out] out_der_integer Buffer to receive the DER-encoded integer
784 : * @return Returns CHIP_ERROR_INVALID_ARGUMENT or CHIP_ERROR_BUFFER_TOO_SMALL on error, CHIP_NO_ERROR otherwise.
785 : */
786 : CHIP_ERROR ConvertIntegerRawToDerWithoutTag(const ByteSpan & raw_integer, MutableByteSpan & out_der_integer);
787 :
788 : /**
789 : * @brief A function that implements AES-CCM encryption
790 : *
791 : * This implements the CHIP_Crypto_AEAD_GenerateEncrypt() cryptographic primitive
792 : * from the specification. For an empty plaintext, the user of the API can provide
793 : * an empty string, or a nullptr, and provide plaintext_length as 0. The output buffer,
794 : * ciphertext can also be an empty string, or a nullptr for this case.
795 : *
796 : * @param plaintext Plaintext to encrypt
797 : * @param plaintext_length Length of plain_text
798 : * @param aad Additional authentication data
799 : * @param aad_length Length of additional authentication data
800 : * @param key Encryption key
801 : * @param nonce Encryption nonce
802 : * @param nonce_length Length of encryption nonce
803 : * @param ciphertext Buffer to write ciphertext into. Caller must ensure this is large enough to hold the ciphertext
804 : * @param tag Buffer to write tag into. Caller must ensure this is large enough to hold the tag
805 : * @param tag_length Expected length of tag
806 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
807 : * */
808 : CHIP_ERROR AES_CCM_encrypt(const uint8_t * plaintext, size_t plaintext_length, const uint8_t * aad, size_t aad_length,
809 : const Aes128KeyHandle & key, const uint8_t * nonce, size_t nonce_length, uint8_t * ciphertext,
810 : uint8_t * tag, size_t tag_length);
811 :
812 : /**
813 : * @brief A function that implements AES-CCM decryption
814 : *
815 : * This implements the CHIP_Crypto_AEAD_DecryptVerify() cryptographic primitive
816 : * from the specification. For an empty ciphertext, the user of the API can provide
817 : * an empty string, or a nullptr, and provide ciphertext_length as 0. The output buffer,
818 : * plaintext can also be an empty string, or a nullptr for this case.
819 : *
820 : * @param ciphertext Ciphertext to decrypt
821 : * @param ciphertext_length Length of ciphertext
822 : * @param aad Additional authentical data.
823 : * @param aad_length Length of additional authentication data
824 : * @param tag Tag to use to decrypt
825 : * @param tag_length Length of tag
826 : * @param key Decryption key
827 : * @param nonce Encryption nonce
828 : * @param nonce_length Length of encryption nonce
829 : * @param plaintext Buffer to write plaintext into
830 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
831 : **/
832 : CHIP_ERROR AES_CCM_decrypt(const uint8_t * ciphertext, size_t ciphertext_length, const uint8_t * aad, size_t aad_length,
833 : const uint8_t * tag, size_t tag_length, const Aes128KeyHandle & key, const uint8_t * nonce,
834 : size_t nonce_length, uint8_t * plaintext);
835 :
836 : /**
837 : * @brief A function that implements AES-CTR encryption/decryption
838 : *
839 : * This implements the AES-CTR-Encrypt/Decrypt() cryptographic primitives per sections
840 : * 3.7.1 and 3.7.2 of the specification. For an empty input, the user of the API
841 : * can provide an empty string, or a nullptr, and provide input as 0.
842 : * The output buffer can also be an empty string, or a nullptr for this case.
843 : *
844 : * @param input Input text to encrypt/decrypt
845 : * @param input_length Length of ciphertext
846 : * @param key Decryption key
847 : * @param nonce Encryption nonce
848 : * @param nonce_length Length of encryption nonce
849 : * @param output Buffer to write output into
850 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
851 : **/
852 : CHIP_ERROR AES_CTR_crypt(const uint8_t * input, size_t input_length, const Aes128KeyHandle & key, const uint8_t * nonce,
853 : size_t nonce_length, uint8_t * output);
854 :
855 : /**
856 : * @brief Generate a PKCS#10 CSR, usable for Matter, from a P256Keypair.
857 : *
858 : * This uses first principles ASN.1 encoding to avoid relying on the CHIPCryptoPAL backend
859 : * itself, other than to provide an implementation of a P256Keypair * that supports
860 : * at least `::Pubkey()` and `::ECDSA_sign_msg`. This allows using it with
861 : * OS/Platform-bridged private key handling, without requiring a specific
862 : * implementation of other bits like ASN.1.
863 : *
864 : * The CSR will have subject OU set to `CSA`. This is needed since omiting
865 : * subject altogether often trips CSR parsing code. The profile at the CA can
866 : * be configured to ignore CSR requested subject.
867 : *
868 : * @param keypair The key pair for which a CSR should be generated. Must not be null.
869 : * @param csr_span Span to hold the resulting CSR. Must have size at least kMIN_CSR_Buffer_Size.
870 : * Otherwise returns CHIP_ERROR_BUFFER_TOO_SMALL. It will get resized to
871 : * actual size needed on success.
872 :
873 : * @return Returns a CHIP_ERROR from P256Keypair or ASN.1 backend on error, CHIP_NO_ERROR otherwise
874 : **/
875 : CHIP_ERROR GenerateCertificateSigningRequest(const P256Keypair * keypair, MutableByteSpan & csr_span);
876 :
877 : /**
878 : * @brief Common code to validate ASN.1 format/size of a CSR, used by VerifyCertificateSigningRequest.
879 : *
880 : * Ensures it's not obviously malformed and doesn't have trailing garbage.
881 : *
882 : * @param csr CSR in DER format
883 : * @param csr_length The length of the CSR buffer
884 : * @return CHIP_ERROR_UNSUPPORTED_CERT_FORMAT on invalid format, CHIP_NO_ERROR otherwise.
885 : */
886 : CHIP_ERROR VerifyCertificateSigningRequestFormat(const uint8_t * csr, size_t csr_length);
887 :
888 : /**
889 : * @brief Verify the Certificate Signing Request (CSR). If successfully verified, it outputs the public key from the CSR.
890 : *
891 : * The CSR is valid if the format is correct, the signature validates with the embedded public
892 : * key, and there is no trailing garbage data.
893 : *
894 : * @param csr CSR in DER format
895 : * @param csr_length The length of the CSR
896 : * @param pubkey The public key from the verified CSR
897 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
898 : **/
899 : CHIP_ERROR VerifyCertificateSigningRequest(const uint8_t * csr, size_t csr_length, P256PublicKey & pubkey);
900 :
901 : /**
902 : * @brief A function that implements SHA-256 hash
903 : *
904 : * This implements the CHIP_Crypto_Hash() cryptographic primitive
905 : * in the the specification.
906 : *
907 : * @param data The data to hash
908 : * @param data_length Length of the data
909 : * @param out_buffer Pointer to buffer to write output into
910 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
911 : **/
912 :
913 : CHIP_ERROR Hash_SHA256(const uint8_t * data, size_t data_length, uint8_t * out_buffer);
914 :
915 : /**
916 : * @brief A function that implements SHA-1 hash
917 : * @param data The data to hash
918 : * @param data_length Length of the data
919 : * @param out_buffer Pointer to buffer to write output into
920 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
921 : **/
922 :
923 : CHIP_ERROR Hash_SHA1(const uint8_t * data, size_t data_length, uint8_t * out_buffer);
924 :
925 : /**
926 : * @brief A class that defines stream based implementation of SHA-256 hash
927 : * It's expected that the object of this class can be safely copied.
928 : * All implementations must check for std::is_trivially_copyable.
929 : **/
930 :
931 : struct alignas(CHIP_CONFIG_SHA256_CONTEXT_ALIGN) HashSHA256OpaqueContext
932 : {
933 : uint8_t mOpaque[kMAX_Hash_SHA256_Context_Size];
934 : };
935 :
936 : class Hash_SHA256_stream
937 : {
938 : public:
939 : Hash_SHA256_stream();
940 : ~Hash_SHA256_stream();
941 :
942 : /**
943 : * @brief Re-initialize digest computation to an empty context.
944 : *
945 : * @return CHIP_ERROR_INTERNAL on failure to initialize the context,
946 : * CHIP_NO_ERROR otherwise.
947 : */
948 : CHIP_ERROR Begin();
949 :
950 : /**
951 : * @brief Add some data to the digest computation, updating internal state.
952 : *
953 : * @param[in] data The span of bytes to include in the digest update process.
954 : *
955 : * @return CHIP_ERROR_INTERNAL on failure to ingest the data, CHIP_NO_ERROR otherwise.
956 : */
957 : CHIP_ERROR AddData(const ByteSpan data);
958 :
959 : /**
960 : * @brief Get the intermediate padded digest for the current state of the stream.
961 : *
962 : * More data can be added before finish is called.
963 : *
964 : * @param[in,out] out_buffer Output buffer to receive the digest. `out_buffer` must
965 : * be at least `kSHA256_Hash_Length` bytes long. The `out_buffer` size
966 : * will be set to `kSHA256_Hash_Length` on success.
967 : *
968 : * @return CHIP_ERROR_INTERNAL on failure to compute the digest, CHIP_ERROR_BUFFER_TOO_SMALL
969 : * if out_buffer is too small, CHIP_NO_ERROR otherwise.
970 : */
971 : CHIP_ERROR GetDigest(MutableByteSpan & out_buffer);
972 :
973 : /**
974 : * @brief Finalize the stream digest computation, getting the final digest.
975 : *
976 : * @param[in,out] out_buffer Output buffer to receive the digest. `out_buffer` must
977 : * be at least `kSHA256_Hash_Length` bytes long. The `out_buffer` size
978 : * will be set to `kSHA256_Hash_Length` on success.
979 : *
980 : * @return CHIP_ERROR_INTERNAL on failure to compute the digest, CHIP_ERROR_BUFFER_TOO_SMALL
981 : * if out_buffer is too small, CHIP_NO_ERROR otherwise.
982 : */
983 : CHIP_ERROR Finish(MutableByteSpan & out_buffer);
984 :
985 : /**
986 : * @brief Clear-out internal digest data to avoid lingering the state.
987 : */
988 : void Clear();
989 :
990 : private:
991 : // Check if the digest computation has been initialized; implement this if your backend needs it.
992 : bool IsInitialized();
993 :
994 : HashSHA256OpaqueContext mContext;
995 : };
996 :
997 : class HKDF_sha
998 : {
999 : public:
1000 : HKDF_sha() = default;
1001 3895 : virtual ~HKDF_sha() = default;
1002 :
1003 : /**
1004 : * @brief A function that implements SHA-256 based HKDF
1005 : *
1006 : * This implements the CHIP_Crypto_KDF() cryptographic primitive
1007 : * in the the specification.
1008 : *
1009 : * Error values are:
1010 : * - CHIP_ERROR_INVALID_ARGUMENT: for any bad arguments or nullptr input on
1011 : * any pointer.
1012 : * - CHIP_ERROR_INTERNAL: for any unexpected error arising in the underlying
1013 : * cryptographic layers.
1014 : *
1015 : * @param secret The secret to use as the key to the HKDF
1016 : * @param secret_length Length of the secret
1017 : * @param salt Optional salt to use as input to the HKDF
1018 : * @param salt_length Length of the salt
1019 : * @param info Optional info to use as input to the HKDF
1020 : * @param info_length Length of the info
1021 : * @param out_buffer Pointer to buffer to write output into.
1022 : * @param out_length Size of the underlying out_buffer. That length of output key material will be generated in out_buffer.
1023 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1024 : **/
1025 :
1026 : virtual CHIP_ERROR HKDF_SHA256(const uint8_t * secret, size_t secret_length, const uint8_t * salt, size_t salt_length,
1027 : const uint8_t * info, size_t info_length, uint8_t * out_buffer, size_t out_length);
1028 : };
1029 :
1030 : class HMAC_sha
1031 : {
1032 : public:
1033 : HMAC_sha() = default;
1034 96 : virtual ~HMAC_sha() = default;
1035 :
1036 : /**
1037 : * @brief A function that implements SHA-256 based HMAC per FIPS1981.
1038 : *
1039 : * This implements the CHIP_Crypto_HMAC() cryptographic primitive
1040 : * in the the specification.
1041 : *
1042 : * The `out_length` must be at least kSHA256_Hash_Length, and only
1043 : * kSHA256_Hash_Length bytes are written to out_buffer.
1044 : *
1045 : * Error values are:
1046 : * - CHIP_ERROR_INVALID_ARGUMENT: for any bad arguments or nullptr input on
1047 : * any pointer.
1048 : * - CHIP_ERROR_INTERNAL: for any unexpected error arising in the underlying
1049 : * cryptographic layers.
1050 : *
1051 : * @param key The key to use for the HMAC operation
1052 : * @param key_length Length of the key
1053 : * @param message Message over which to compute the HMAC
1054 : * @param message_length Length of the message over which to compute the HMAC
1055 : * @param out_buffer Pointer to buffer into which to write the output.
1056 : * @param out_length Underlying size of the `out_buffer`.
1057 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1058 : **/
1059 :
1060 : virtual CHIP_ERROR HMAC_SHA256(const uint8_t * key, size_t key_length, const uint8_t * message, size_t message_length,
1061 : uint8_t * out_buffer, size_t out_length);
1062 :
1063 : /**
1064 : * @brief A function that implements SHA-256 based HMAC per FIPS1981.
1065 : *
1066 : * This implements the CHIP_Crypto_HMAC() cryptographic primitive
1067 : * in the the specification.
1068 : *
1069 : * The `out_length` must be at least kSHA256_Hash_Length, and only
1070 : * kSHA256_Hash_Length bytes are written to out_buffer.
1071 : *
1072 : * Error values are:
1073 : * - CHIP_ERROR_INVALID_ARGUMENT: for any bad arguments or nullptr input on
1074 : * any pointer.
1075 : * - CHIP_ERROR_INTERNAL: for any unexpected error arising in the underlying
1076 : * cryptographic layers.
1077 : *
1078 : * @param key The HMAC Key handle to use for the HMAC operation
1079 : * @param message Message over which to compute the HMAC
1080 : * @param message_length Length of the message over which to compute the HMAC
1081 : * @param out_buffer Pointer to buffer into which to write the output.
1082 : * @param out_length Underlying size of the `out_buffer`.
1083 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1084 : **/
1085 : virtual CHIP_ERROR HMAC_SHA256(const Hmac128KeyHandle & key, const uint8_t * message, size_t message_length,
1086 : uint8_t * out_buffer, size_t out_length);
1087 : };
1088 :
1089 : /**
1090 : * @brief A cryptographically secure random number generator based on NIST SP800-90A
1091 : * @param out_buffer Buffer into which to write random bytes
1092 : * @param out_length Number of random bytes to generate
1093 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1094 : **/
1095 : CHIP_ERROR DRBG_get_bytes(uint8_t * out_buffer, size_t out_length);
1096 :
1097 : /** @brief Entropy callback function
1098 : * @param data Callback-specific data pointer
1099 : * @param output Output data to fill
1100 : * @param len Length of output buffer
1101 : * @param olen The actual amount of data that was written to output buffer
1102 : * @return 0 if success
1103 : */
1104 : typedef int (*entropy_source)(void * data, uint8_t * output, size_t len, size_t * olen);
1105 :
1106 : /** @brief A function to add entropy sources to crypto library
1107 : *
1108 : * This function can be called multiple times to add multiple entropy sources. However,
1109 : * once the entropy source is added, it cannot be removed. Please make sure that the
1110 : * entropy source is valid for the lifetime of the application. Also, make sure that the
1111 : * same entropy source is not added multiple times, e.g.: by calling this function
1112 : * in class constructor or initialization function.
1113 : *
1114 : * @param fn_source Function pointer to the entropy source
1115 : * @param p_source Data that should be provided when fn_source is called
1116 : * @param threshold Minimum required from source before entropy is released
1117 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1118 : **/
1119 : CHIP_ERROR add_entropy_source(entropy_source fn_source, void * p_source, size_t threshold);
1120 :
1121 : class PBKDF2_sha256
1122 : {
1123 : public:
1124 : PBKDF2_sha256() = default;
1125 9 : virtual ~PBKDF2_sha256() = default;
1126 :
1127 : /** @brief Function to derive key using password. SHA256 hashing algorithm is used for calculating hmac.
1128 : * @param password password used for key derivation
1129 : * @param plen length of buffer containing password
1130 : * @param salt salt to use as input to the KDF
1131 : * @param slen length of salt
1132 : * @param iteration_count number of iterations to run
1133 : * @param key_length length of output key
1134 : * @param output output buffer where the key will be written
1135 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1136 : **/
1137 : virtual CHIP_ERROR pbkdf2_sha256(const uint8_t * password, size_t plen, const uint8_t * salt, size_t slen,
1138 : unsigned int iteration_count, uint32_t key_length, uint8_t * output);
1139 : };
1140 :
1141 : // TODO: Extract Spake2p to a separate header and replace the forward declaration with #include SessionKeystore.h
1142 : class SessionKeystore;
1143 :
1144 : /**
1145 : * The below class implements the draft 01 version of the Spake2+ protocol as
1146 : * defined in https://www.ietf.org/id/draft-bar-cfrg-spake2plus-01.html.
1147 : *
1148 : * The following describes the protocol flows:
1149 : *
1150 : * Commissioner Accessory
1151 : * ------------ ---------
1152 : *
1153 : * Init
1154 : * BeginProver
1155 : * ComputeRoundOne ------------->
1156 : * Init
1157 : * BeginVerifier
1158 : * /- ComputeRoundOne
1159 : * <------------- ComputeRoundTwo
1160 : * ComputeRoundTwo ------------->
1161 : * KeyConfirm KeyConfirm
1162 : * GetKeys GetKeys
1163 : *
1164 : **/
1165 : class Spake2p
1166 : {
1167 : public:
1168 : Spake2p(size_t fe_size, size_t point_size, size_t hash_size);
1169 25 : virtual ~Spake2p() = default;
1170 :
1171 : /**
1172 : * @brief Initialize Spake2+ with some context specific information.
1173 : *
1174 : * @param context The context is arbitrary but should include information about the
1175 : * protocol being run, contain the transcript for negotiation, include
1176 : * the PKBDF parameters, etc.
1177 : * @param context_len The length of the context.
1178 : *
1179 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1180 : **/
1181 : virtual CHIP_ERROR Init(const uint8_t * context, size_t context_len);
1182 :
1183 : /**
1184 : * @brief Free Spake2+ underlying objects.
1185 : **/
1186 : virtual void Clear() = 0;
1187 :
1188 : /**
1189 : * @brief Start the Spake2+ process as a verifier (i.e. an accessory being provisioned).
1190 : *
1191 : * @param my_identity The verifier identity. May be NULL if identities are not established.
1192 : * @param my_identity_len The verifier identity length.
1193 : * @param peer_identity The peer identity. May be NULL if identities are not established.
1194 : * @param peer_identity_len The peer identity length.
1195 : * @param w0in The input w0 (a parameter baked into the device or computed with ComputeW0).
1196 : * @param w0in_len The input w0 length.
1197 : * @param Lin The input L (a parameter baked into the device or computed with ComputeL).
1198 : * @param Lin_len The input L length.
1199 : *
1200 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1201 : **/
1202 : virtual CHIP_ERROR BeginVerifier(const uint8_t * my_identity, size_t my_identity_len, const uint8_t * peer_identity,
1203 : size_t peer_identity_len, const uint8_t * w0in, size_t w0in_len, const uint8_t * Lin,
1204 : size_t Lin_len);
1205 :
1206 : /**
1207 : * @brief Start the Spake2+ process as a prover (i.e. a commissioner).
1208 : *
1209 : * @param my_identity The prover identity. May be NULL if identities are not established.
1210 : * @param my_identity_len The prover identity length.
1211 : * @param peer_identity The peer identity. May be NULL if identities are not established.
1212 : * @param peer_identity_len The peer identity length.
1213 : * @param w0sin The input w0s (an output from the PBKDF).
1214 : * @param w0sin_len The input w0s length.
1215 : * @param w1sin The input w1s (an output from the PBKDF).
1216 : * @param w1sin_len The input w1s length.
1217 : *
1218 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1219 : **/
1220 : virtual CHIP_ERROR BeginProver(const uint8_t * my_identity, size_t my_identity_len, const uint8_t * peer_identity,
1221 : size_t peer_identity_len, const uint8_t * w0sin, size_t w0sin_len, const uint8_t * w1sin,
1222 : size_t w1sin_len);
1223 :
1224 : /**
1225 : * @brief Compute the first round of the protocol.
1226 : *
1227 : * @param pab X value from commissioner.
1228 : * @param pab_len X length.
1229 : * @param out The output first round Spake2+ contribution.
1230 : * @param out_len The output first round Spake2+ contribution length.
1231 : *
1232 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1233 : **/
1234 : virtual CHIP_ERROR ComputeRoundOne(const uint8_t * pab, size_t pab_len, uint8_t * out, size_t * out_len);
1235 :
1236 : /**
1237 : * @brief Compute the second round of the protocol.
1238 : *
1239 : * @param in The peer first round Spake2+ contribution.
1240 : * @param in_len The peer first round Spake2+ contribution length.
1241 : * @param out The output second round Spake2+ contribution.
1242 : * @param out_len The output second round Spake2+ contribution length.
1243 : *
1244 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1245 : **/
1246 : virtual CHIP_ERROR ComputeRoundTwo(const uint8_t * in, size_t in_len, uint8_t * out, size_t * out_len);
1247 :
1248 : /**
1249 : * @brief Confirm that each party computed the same keys.
1250 : *
1251 : * @param in The peer second round Spake2+ contribution.
1252 : * @param in_len The peer second round Spake2+ contribution length.
1253 : *
1254 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1255 : **/
1256 : virtual CHIP_ERROR KeyConfirm(const uint8_t * in, size_t in_len);
1257 :
1258 : /**
1259 : * @brief Return the shared HKDF key.
1260 : *
1261 : * Returns the shared key established during the Spake2+ process, which can be used
1262 : * to derive application-specific keys using HKDF.
1263 : *
1264 : * @param keystore The session keystore for managing the HKDF key lifetime.
1265 : * @param key The output HKDF key.
1266 : *
1267 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1268 : **/
1269 : CHIP_ERROR GetKeys(SessionKeystore & keystore, HkdfKeyHandle & key);
1270 :
1271 : CHIP_ERROR InternalHash(const uint8_t * in, size_t in_len);
1272 : CHIP_ERROR WriteMN();
1273 : CHIP_ERROR GenerateKeys();
1274 :
1275 : /**
1276 : * @brief Load a field element.
1277 : *
1278 : * @param in The input big endian field element.
1279 : * @param in_len The size of the input buffer in bytes.
1280 : * @param fe A pointer to an initialized implementation dependant field element.
1281 : *
1282 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1283 : **/
1284 : virtual CHIP_ERROR FELoad(const uint8_t * in, size_t in_len, void * fe) = 0;
1285 :
1286 : /**
1287 : * @brief Write a field element in big-endian format.
1288 : *
1289 : * @param fe The field element to write.
1290 : * @param out The output buffer.
1291 : * @param out_len The length of the output buffer.
1292 : *
1293 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1294 : **/
1295 : virtual CHIP_ERROR FEWrite(const void * fe, uint8_t * out, size_t out_len) = 0;
1296 :
1297 : /**
1298 : * @brief Generate a field element.
1299 : *
1300 : * @param fe A pointer to an initialized implementation dependant field element.
1301 : *
1302 : * @note The implementation must generate a random element from [0, q) where q is the curve order.
1303 : *
1304 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1305 : **/
1306 : virtual CHIP_ERROR FEGenerate(void * fe) = 0;
1307 :
1308 : /**
1309 : * @brief Multiply two field elements, fer = fe1 * fe2.
1310 : *
1311 : * @param fer A pointer to an initialized implementation dependant field element.
1312 : * @param fe1 A pointer to an initialized implementation dependant field element.
1313 : * @param fe2 A pointer to an initialized implementation dependant field element.
1314 : *
1315 : * @note The result must be a field element (i.e. reduced by the curve order).
1316 : *
1317 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1318 : **/
1319 : virtual CHIP_ERROR FEMul(void * fer, const void * fe1, const void * fe2) = 0;
1320 :
1321 : /**
1322 : * @brief Load a point from 0x04 || X || Y format
1323 : *
1324 : * @param in Input buffer
1325 : * @param in_len Input buffer length
1326 : * @param R A pointer to an initialized implementation dependant point.
1327 : *
1328 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1329 : **/
1330 : virtual CHIP_ERROR PointLoad(const uint8_t * in, size_t in_len, void * R) = 0;
1331 :
1332 : /**
1333 : * @brief Write a point in 0x04 || X || Y format
1334 : *
1335 : * @param R A pointer to an initialized implementation dependant point.
1336 : * @param out Output buffer
1337 : * @param out_len Length of the output buffer
1338 : *
1339 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1340 : **/
1341 : virtual CHIP_ERROR PointWrite(const void * R, uint8_t * out, size_t out_len) = 0;
1342 :
1343 : /**
1344 : * @brief Scalar multiplication, R = fe1 * P1.
1345 : *
1346 : * @param R Resultant point
1347 : * @param P1 Input point
1348 : * @param fe1 Input field element.
1349 : *
1350 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1351 : **/
1352 : virtual CHIP_ERROR PointMul(void * R, const void * P1, const void * fe1) = 0;
1353 :
1354 : /**
1355 : * @brief Scalar multiplication with addition, R = fe1 * P1 + fe2 * P2.
1356 : *
1357 : * @param R Resultant point
1358 : * @param P1 Input point
1359 : * @param fe1 Input field element.
1360 : * @param P2 Input point
1361 : * @param fe2 Input field element.
1362 : *
1363 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1364 : **/
1365 : virtual CHIP_ERROR PointAddMul(void * R, const void * P1, const void * fe1, const void * P2, const void * fe2) = 0;
1366 :
1367 : /**
1368 : * @brief Point inversion.
1369 : *
1370 : * @param R Input/Output point to point_invert
1371 : *
1372 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1373 : **/
1374 : virtual CHIP_ERROR PointInvert(void * R) = 0;
1375 :
1376 : /**
1377 : * @brief Multiply a point by the curve cofactor.
1378 : *
1379 : * @param R Input/Output point to point_invert
1380 : *
1381 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1382 : **/
1383 : virtual CHIP_ERROR PointCofactorMul(void * R) = 0;
1384 :
1385 : /*
1386 : * @synopsis Check if a point is on the curve.
1387 : *
1388 : * @param R Input point to check.
1389 : *
1390 : * @return CHIP_NO_ERROR if the point is valid, CHIP_ERROR otherwise.
1391 : */
1392 : virtual CHIP_ERROR PointIsValid(void * R) = 0;
1393 :
1394 : /*
1395 : * @synopsis Compute w0sin mod p
1396 : *
1397 : * @param w0out Output field element w0
1398 : * @param w0_len Output field element length
1399 : * @param w0sin Input field element
1400 : * @param w0sin_len Input field element length
1401 : *
1402 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1403 : **/
1404 : virtual CHIP_ERROR ComputeW0(uint8_t * w0out, size_t * w0_len, const uint8_t * w0sin, size_t w0sin_len) = 0;
1405 :
1406 : /*
1407 : * @synopsis Compute w1in*G where w1in is w1sin mod p
1408 : *
1409 : * @param Lout Output point in 0x04 || X || Y format.
1410 : * @param L_len Output point length
1411 : * @param w1sin Input field element
1412 : * @param w1sin_len Input field element size
1413 : *
1414 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1415 : **/
1416 : virtual CHIP_ERROR ComputeL(uint8_t * Lout, size_t * L_len, const uint8_t * w1sin, size_t w1sin_len) = 0;
1417 :
1418 : void * M;
1419 : void * N;
1420 : const void * G;
1421 : void * X;
1422 : void * Y;
1423 : void * L;
1424 : void * Z;
1425 : void * V;
1426 : void * w0;
1427 : void * w1;
1428 : void * xy;
1429 : void * order;
1430 : void * tempbn;
1431 :
1432 : protected:
1433 : /**
1434 : * @brief Initialize underlying implementation curve, points, field elements, etc.
1435 : *
1436 : * @details The implementation needs to:
1437 : * 1. Initialize each of the points below and set the relevant pointers on the class:
1438 : * a. M
1439 : * b. N
1440 : * c. G
1441 : * d. X
1442 : * e. Y
1443 : * f. L
1444 : * g. Z
1445 : * h. V
1446 : *
1447 : * As an example:
1448 : * this.M = implementation_alloc_point();
1449 : * 2. Initialize each of the field elements below and set the relevant pointers on the class:
1450 : * a. w0
1451 : * b. w1
1452 : * c. xy
1453 : * d. tempbn
1454 : * 3. The hashing context should be initialized
1455 : *
1456 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1457 : **/
1458 : virtual CHIP_ERROR InitImpl() = 0;
1459 :
1460 : /**
1461 : * @brief Hash in_len bytes of in into the internal hash context.
1462 : *
1463 : * @param in The input buffer.
1464 : * @param in_len Size of the input buffer in bytes.
1465 : *
1466 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1467 : **/
1468 : virtual CHIP_ERROR Hash(const uint8_t * in, size_t in_len) = 0;
1469 :
1470 : /**
1471 : * @brief Return the hash.
1472 : *
1473 : * @param out_span Output buffer. The size available must be >= the hash size. It gets resized
1474 : * to hash size on success.
1475 : *
1476 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1477 : **/
1478 : virtual CHIP_ERROR HashFinalize(MutableByteSpan & out_span) = 0;
1479 :
1480 : /**
1481 : * @brief Generate a message authentication code.
1482 : *
1483 : * @param key The MAC key buffer.
1484 : * @param key_len The size of the MAC key in bytes.
1485 : * @param in The input buffer.
1486 : * @param in_len The size of the input data to MAC in bytes.
1487 : * @param out_span The output MAC buffer span. Size must be >= the hash_size. Output size is updated to fit on success.
1488 : *
1489 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1490 : **/
1491 : virtual CHIP_ERROR Mac(const uint8_t * key, size_t key_len, const uint8_t * in, size_t in_len, MutableByteSpan & out_span) = 0;
1492 :
1493 : /**
1494 : * @brief Verify a message authentication code.
1495 : *
1496 : * @param key The MAC key buffer.
1497 : * @param key_len The size of the MAC key in bytes.
1498 : * @param mac The input MAC buffer.
1499 : * @param mac_len The size of the MAC in bytes.
1500 : * @param in The input buffer to verify.
1501 : * @param in_len The size of the input data to verify in bytes.
1502 : *
1503 : * @return Returns a CHIP_ERROR when the MAC doesn't validate, CHIP_NO_ERROR otherwise.
1504 : **/
1505 : virtual CHIP_ERROR MacVerify(const uint8_t * key, size_t key_len, const uint8_t * mac, size_t mac_len, const uint8_t * in,
1506 : size_t in_len) = 0;
1507 :
1508 : /**
1509 : * @brief Derive an key of length out_len.
1510 : *
1511 : * @param ikm The input key material buffer.
1512 : * @param ikm_len The input key material length.
1513 : * @param salt The optional salt. This may be NULL.
1514 : * @param salt_len The size of the salt in bytes.
1515 : * @param info The info.
1516 : * @param info_len The size of the info in bytes.
1517 : * @param out The output key
1518 : * @param out_len The output key length
1519 : *
1520 : * @return Returns a CHIP_ERROR when the MAC doesn't validate, CHIP_NO_ERROR otherwise.
1521 : **/
1522 : virtual CHIP_ERROR KDF(const uint8_t * ikm, size_t ikm_len, const uint8_t * salt, size_t salt_len, const uint8_t * info,
1523 : size_t info_len, uint8_t * out, size_t out_len) = 0;
1524 :
1525 : CHIP_SPAKE2P_ROLE role;
1526 : CHIP_SPAKE2P_STATE state = CHIP_SPAKE2P_STATE::PREINIT;
1527 : size_t fe_size;
1528 : size_t hash_size;
1529 : size_t point_size;
1530 : uint8_t Kcab[kMAX_Hash_Length];
1531 : uint8_t Kae[kMAX_Hash_Length];
1532 : uint8_t * Kca;
1533 : uint8_t * Kcb;
1534 : uint8_t * Ka;
1535 : uint8_t * Ke;
1536 : };
1537 :
1538 : struct alignas(size_t) Spake2pOpaqueContext
1539 : {
1540 : uint8_t mOpaque[kMAX_Spake2p_Context_Size];
1541 : };
1542 :
1543 : class Spake2p_P256_SHA256_HKDF_HMAC : public Spake2p
1544 : {
1545 : public:
1546 10 : Spake2p_P256_SHA256_HKDF_HMAC() : Spake2p(kP256_FE_Length, kP256_Point_Length, kSHA256_Hash_Length)
1547 : {
1548 10 : memset(&mSpake2pContext, 0, sizeof(mSpake2pContext));
1549 10 : }
1550 :
1551 25 : ~Spake2p_P256_SHA256_HKDF_HMAC() override { Spake2p_P256_SHA256_HKDF_HMAC::Clear(); }
1552 :
1553 : void Clear() override;
1554 : CHIP_ERROR Mac(const uint8_t * key, size_t key_len, const uint8_t * in, size_t in_len, MutableByteSpan & out_span) override;
1555 : CHIP_ERROR MacVerify(const uint8_t * key, size_t key_len, const uint8_t * mac, size_t mac_len, const uint8_t * in,
1556 : size_t in_len) override;
1557 : CHIP_ERROR FELoad(const uint8_t * in, size_t in_len, void * fe) override;
1558 : CHIP_ERROR FEWrite(const void * fe, uint8_t * out, size_t out_len) override;
1559 : CHIP_ERROR FEGenerate(void * fe) override;
1560 : CHIP_ERROR FEMul(void * fer, const void * fe1, const void * fe2) override;
1561 :
1562 : CHIP_ERROR PointLoad(const uint8_t * in, size_t in_len, void * R) override;
1563 : CHIP_ERROR PointWrite(const void * R, uint8_t * out, size_t out_len) override;
1564 : CHIP_ERROR PointMul(void * R, const void * P1, const void * fe1) override;
1565 : CHIP_ERROR PointAddMul(void * R, const void * P1, const void * fe1, const void * P2, const void * fe2) override;
1566 : CHIP_ERROR PointInvert(void * R) override;
1567 : CHIP_ERROR PointCofactorMul(void * R) override;
1568 : CHIP_ERROR PointIsValid(void * R) override;
1569 :
1570 : CHIP_ERROR ComputeW0(uint8_t * w0out, size_t * w0_len, const uint8_t * w0sin, size_t w0sin_len) override;
1571 : CHIP_ERROR ComputeL(uint8_t * Lout, size_t * L_len, const uint8_t * w1sin, size_t w1sin_len) override;
1572 :
1573 : protected:
1574 : CHIP_ERROR InitImpl() override;
1575 : CHIP_ERROR Hash(const uint8_t * in, size_t in_len) override;
1576 : CHIP_ERROR HashFinalize(MutableByteSpan & out_span) override;
1577 : CHIP_ERROR KDF(const uint8_t * secret, size_t secret_length, const uint8_t * salt, size_t salt_length, const uint8_t * info,
1578 : size_t info_length, uint8_t * out, size_t out_length) override;
1579 :
1580 : private:
1581 : CHIP_ERROR InitInternal();
1582 : Hash_SHA256_stream sha256_hash_ctx;
1583 :
1584 : Spake2pOpaqueContext mSpake2pContext;
1585 : };
1586 :
1587 : /**
1588 : * @brief Class used for verifying PASE secure sessions.
1589 : **/
1590 : class Spake2pVerifier
1591 : {
1592 : public:
1593 : uint8_t mW0[kP256_FE_Length];
1594 : uint8_t mL[kP256_Point_Length];
1595 :
1596 : CHIP_ERROR Serialize(MutableByteSpan & outSerialized) const;
1597 : CHIP_ERROR Deserialize(const ByteSpan & inSerialized);
1598 :
1599 : /**
1600 : * @brief Generate the Spake2+ verifier.
1601 : *
1602 : * @param pbkdf2IterCount Iteration count for PBKDF2 function
1603 : * @param salt Salt to be used for Spake2+ operation
1604 : * @param setupPin Provided setup PIN (passcode)
1605 : *
1606 : * @return CHIP_ERROR The result of Spake2+ verifier generation
1607 : */
1608 : CHIP_ERROR Generate(uint32_t pbkdf2IterCount, const ByteSpan & salt, uint32_t setupPin);
1609 :
1610 : /**
1611 : * @brief Compute the initiator values (w0s, w1s) used for PAKE input.
1612 : *
1613 : * @param pbkdf2IterCount Iteration count for PBKDF2 function
1614 : * @param salt Salt to be used for Spake2+ operation
1615 : * @param setupPin Provided setup PIN (passcode)
1616 : * @param ws The output pair (w0s, w1s) stored sequentially
1617 : * @param ws_len The output length
1618 : *
1619 : * @return CHIP_ERROR The result from running PBKDF2
1620 : */
1621 : static CHIP_ERROR ComputeWS(uint32_t pbkdf2IterCount, const ByteSpan & salt, uint32_t setupPin, uint8_t * ws, uint32_t ws_len);
1622 : };
1623 :
1624 : /**
1625 : * @brief Serialized format of the Spake2+ Verifier components.
1626 : *
1627 : * This is used when the Verifier should be presented in a serialized form.
1628 : * For example, when it is generated using PBKDF function, when stored in the
1629 : * memory or when sent over the wire.
1630 : * The serialized format is concatentation of 'W0' and 'L' verifier components:
1631 : * { Spake2pVerifier.mW0[kP256_FE_Length], Spake2pVerifier.mL[kP256_Point_Length] }
1632 : **/
1633 : typedef uint8_t Spake2pVerifierSerialized[kSpake2p_VerifierSerialized_Length];
1634 :
1635 : /**
1636 : * @brief Compute the compressed fabric identifier used for operational discovery service
1637 : * records from a Node's root public key and Fabric ID. On success, out_compressed_fabric_id
1638 : * will have a size of exactly kCompressedFabricIdentifierSize.
1639 : *
1640 : * Errors are:
1641 : * - CHIP_ERROR_INVALID_ARGUMENT if root_public_key is invalid
1642 : * - CHIP_ERROR_BUFFER_TOO_SMALL if out_compressed_fabric_id is too small for serialization
1643 : * - CHIP_ERROR_INTERNAL on any unexpected crypto or data conversion errors.
1644 : *
1645 : * @param[in] root_public_key The root public key associated with the node's fabric
1646 : * @param[in] fabric_id The fabric ID associated with the node's fabric
1647 : * @param[out] out_compressed_fabric_id Span where output will be written. Its size must be >= kCompressedFabricIdentifierSize.
1648 : * @returns a CHIP_ERROR (see above) on failure or CHIP_NO_ERROR otherwise.
1649 : */
1650 : CHIP_ERROR GenerateCompressedFabricId(const Crypto::P256PublicKey & root_public_key, uint64_t fabric_id,
1651 : MutableByteSpan & out_compressed_fabric_id);
1652 :
1653 : /**
1654 : * @brief Compute the compressed fabric identifier used for operational discovery service
1655 : * records from a Node's root public key and Fabric ID. This is a conveniance
1656 : * overload that writes to a uint64_t (CompressedFabricId) type.
1657 : *
1658 : * @param[in] rootPublicKey The root public key associated with the node's fabric
1659 : * @param[in] fabricId The fabric ID associated with the node's fabric
1660 : * @param[out] compressedFabricId output location for compressed fabric ID
1661 : * @returns a CHIP_ERROR on failure or CHIP_NO_ERROR otherwise.
1662 : */
1663 : CHIP_ERROR GenerateCompressedFabricId(const Crypto::P256PublicKey & rootPublicKey, uint64_t fabricId,
1664 : uint64_t & compressedFabricId);
1665 :
1666 : enum class CertificateChainValidationResult
1667 : {
1668 : kSuccess = 0,
1669 :
1670 : kRootFormatInvalid = 100,
1671 : kRootArgumentInvalid = 101,
1672 :
1673 : kICAFormatInvalid = 200,
1674 : kICAArgumentInvalid = 201,
1675 :
1676 : kLeafFormatInvalid = 300,
1677 : kLeafArgumentInvalid = 301,
1678 :
1679 : kChainInvalid = 400,
1680 :
1681 : kNoMemory = 500,
1682 :
1683 : kInternalFrameworkError = 600,
1684 : };
1685 :
1686 : CHIP_ERROR ValidateCertificateChain(const uint8_t * rootCertificate, size_t rootCertificateLen, const uint8_t * caCertificate,
1687 : size_t caCertificateLen, const uint8_t * leafCertificate, size_t leafCertificateLen,
1688 : CertificateChainValidationResult & result);
1689 :
1690 : enum class AttestationCertType
1691 : {
1692 : kPAA = 0,
1693 : kPAI = 1,
1694 : kDAC = 2,
1695 : };
1696 :
1697 : CHIP_ERROR VerifyAttestationCertificateFormat(const ByteSpan & cert, AttestationCertType certType);
1698 :
1699 : /**
1700 : * @brief Generate a VendorFabricBindingMessage as used by the Fabric Table Vendor ID Verification Procedure.
1701 : *
1702 : * @param[in] fabricBindingVersion - Version of binding payload to generate. outputSpan size requirements are based on this.
1703 : * @param[in] rootPublicKey - Root public key for the fabric in question
1704 : * @param[in] fabricId - Fabric ID for the fabric in question
1705 : * @param[in] vendorId - Vendor ID for the fabric in question
1706 : * @param[inout] outputSpan - Span that will receive the binding message. Must be large enough for the
1707 : * payload (otherwise CHIP_ERROR_BUFFER_TOO_SMALL) and will be resized to fit.
1708 : * @return CHIP_NO_ERROR on success, otherwise another CHIP_ERROR value representative of the failure.
1709 : */
1710 : CHIP_ERROR GenerateVendorFabricBindingMessage(FabricBindingVersion fabricBindingVersion, const P256PublicKey & rootPublicKey,
1711 : FabricId fabricId, uint16_t vendorId, MutableByteSpan & outputSpan);
1712 :
1713 : /**
1714 : * @brief Generate the message to be signed for the Fabric Table Vendor ID Verification Procedure.
1715 : *
1716 : * The Fabric Binding Version value will be recovered from the vendorFabricBindingMessage.
1717 : *
1718 : * @param fabricIndex - Fabric Index for the fabric in question
1719 : * @param clientChallenge - Client challenge to use
1720 : * @param attestationChallenge - Attestation challenge to use
1721 : * @param vendorFabricBindingMessage - The VendorFabricBindingMessage previously computed for the fabric
1722 : * @param vidVerificationStatement - The VID Verification Statement to include in signature (may be empty)
1723 : * @param outputSpan - Span that will receive the to-be-signed message. Must be large enough for the
1724 : * payload (otherwise CHIP_ERROR_BUFFER_TOO_SMALL) and will be resized to fit.
1725 : * @return CHIP_NO_ERROR on success, otherwise another CHIP_ERROR value representative of the failure.
1726 : */
1727 : CHIP_ERROR GenerateVendorIdVerificationToBeSigned(FabricIndex fabricIndex, const ByteSpan & clientChallenge,
1728 : const ByteSpan & attestationChallenge,
1729 : const ByteSpan & vendorFabricBindingMessage,
1730 : const ByteSpan & vidVerificationStatement, MutableByteSpan & outputSpan);
1731 :
1732 : /**
1733 : * @brief Validate notBefore timestamp of a certificate (candidateCertificate) against validity period of the
1734 : * issuer certificate (issuerCertificate).
1735 : *
1736 : * Errors are:
1737 : * - CHIP_ERROR_CERT_EXPIRED if the candidateCertificate timestamp does not satisfy the issuerCertificate's timestamp.
1738 : * - CHIP_ERROR_INVALID_ARGUMENT when passing an invalid argument.
1739 : * - CHIP_ERROR_INTERNAL on any unexpected crypto or data conversion errors.
1740 : *
1741 : * @param candidateCertificate A DER Certificate ByteSpan those notBefore timestamp to be evaluated.
1742 : * @param issuerCertificate A DER Certificate ByteSpan used to evaluate validity timestamp of the candidateCertificate.
1743 : *
1744 : * @returns a CHIP_ERROR (see above) on failure or CHIP_NO_ERROR otherwise.
1745 : **/
1746 : CHIP_ERROR IsCertificateValidAtIssuance(const ByteSpan & candidateCertificate, const ByteSpan & issuerCertificate);
1747 :
1748 : /**
1749 : * @brief Validate a certificate's validity date against current time.
1750 : *
1751 : * Errors are:
1752 : * - CHIP_ERROR_CERT_EXPIRED if the certificate has expired.
1753 : * - CHIP_ERROR_INVALID_ARGUMENT when passing an invalid argument.
1754 : * - CHIP_ERROR_INTERNAL on any unexpected crypto or data conversion errors.
1755 : *
1756 : * @param certificate A DER Certificate ByteSpan used as the validity reference to be checked against current time.
1757 : *
1758 : * @returns a CHIP_ERROR (see above) on failure or CHIP_NO_ERROR otherwise.
1759 : **/
1760 : CHIP_ERROR IsCertificateValidAtCurrentTime(const ByteSpan & certificate);
1761 :
1762 : CHIP_ERROR ExtractPubkeyFromX509Cert(const ByteSpan & certificate, Crypto::P256PublicKey & pubkey);
1763 :
1764 : /**
1765 : * @brief Extracts the Subject Key Identifier from an X509 Certificate.
1766 : **/
1767 : CHIP_ERROR ExtractSKIDFromX509Cert(const ByteSpan & certificate, MutableByteSpan & skid);
1768 :
1769 : /**
1770 : * @brief Extracts the Authority Key Identifier from an X509 Certificate.
1771 : **/
1772 : CHIP_ERROR ExtractAKIDFromX509Cert(const ByteSpan & certificate, MutableByteSpan & akid);
1773 :
1774 : /**
1775 : * @brief Extracts the CRL Distribution Point (CDP) extension from an X509 ASN.1 Encoded Certificate.
1776 : * The returned value only covers the URI of the CDP. Only a single URI distribution point
1777 : * GeneralName is supported, and only those that start with "http://" and "https://".
1778 : *
1779 : * @returns CHIP_ERROR_NOT_FOUND if not found or wrong format.
1780 : * CHIP_NO_ERROR otherwise.
1781 : **/
1782 : CHIP_ERROR ExtractCRLDistributionPointURIFromX509Cert(const ByteSpan & certificate, MutableCharSpan & cdpurl);
1783 :
1784 : /**
1785 : * @brief Extracts the CRL Distribution Point (CDP) extension's cRLIssuer Name from an X509 ASN.1 Encoded Certificate.
1786 : * The value is copied into buffer in a raw ASN.1 X.509 format. This format should be directly comparable
1787 : * with the result of ExtractSubjectFromX509Cert().
1788 : *
1789 : * @returns CHIP_ERROR_NOT_FOUND if not found or wrong format.
1790 : * CHIP_NO_ERROR otherwise.
1791 : **/
1792 : CHIP_ERROR ExtractCDPExtensionCRLIssuerFromX509Cert(const ByteSpan & certificate, MutableByteSpan & crlIssuer);
1793 :
1794 : /**
1795 : * @brief Extracts Serial Number from X509 Certificate.
1796 : **/
1797 : CHIP_ERROR ExtractSerialNumberFromX509Cert(const ByteSpan & certificate, MutableByteSpan & serialNumber);
1798 :
1799 : /**
1800 : * @brief Extracts Subject Distinguished Name from X509 Certificate. The value is copied into buffer in a raw ASN.1 X.509 format.
1801 : **/
1802 : CHIP_ERROR ExtractSubjectFromX509Cert(const ByteSpan & certificate, MutableByteSpan & subject);
1803 :
1804 : /**
1805 : * @brief Extracts Issuer Distinguished Name from X509 Certificate. The value is copied into buffer in a raw ASN.1 X.509 format.
1806 : **/
1807 : CHIP_ERROR ExtractIssuerFromX509Cert(const ByteSpan & certificate, MutableByteSpan & issuer);
1808 :
1809 : class PemEncoder
1810 : {
1811 : public:
1812 : /**
1813 : * @brief Construct a PEM encoder for element type `encodedElement` whose DER data is in `derBytes` span.
1814 : *
1815 : * LIFETIME: both encodedElement and derBytes lifetime must be >= PemEncoder lifetime.
1816 : * PemEncoder references these while processing `NextLine()` calls.
1817 : *
1818 : * @param encodedElement - Element type string to include in header/footer (e.g. "CERTIFICATE"). Caller must provide correct
1819 : * uppercase.
1820 : * @param derBytes - Byte span containing data to encode. May be empty.
1821 : */
1822 3 : explicit PemEncoder(const char * encodedElement, ByteSpan derBytes) : mEncodedElement(encodedElement), mDerBytes(derBytes) {}
1823 :
1824 : // No copies.
1825 : PemEncoder(const PemEncoder &) = delete;
1826 : PemEncoder & operator=(const PemEncoder &) = delete;
1827 :
1828 : /**
1829 : * @brief Returns the pointer to the next null-terminated line of the encoding, or nullptr if done.
1830 : *
1831 : * The returned pointer has the lifetime of this class and during that lifetime will always point
1832 : * to valid memory.
1833 : *
1834 : * When header/footer are written, the heading type (`encodedElement` value) such as
1835 : * `CERTIFICATE` is clamped so that the entire header line with `-----BEGIN ${encodedElement}-----`
1836 : * and footer line with `-----END ${encodedElement}-----` are not wider than 64 bytes. This
1837 : * will not happen in practice with the types of things this is meant to encode.
1838 : *
1839 : * Usage should be in a loop, for example:
1840 : *
1841 : * std::vector<std::string> pemLines;
1842 : *
1843 : * PemEncoder encoder("CERTIFICATE", TestCerts::sTestCert_PAA_FFF1_Cert);
1844 : *
1845 : * const char* line = encoder.NextLine();
1846 : * while (line)
1847 : * {
1848 : * pemLines.push_back(std::string{ line });
1849 : * line = encoder.NextLine();
1850 : * }
1851 : *
1852 : * @return a pointer to the internal line buffer for next line or nullptr when done.
1853 : */
1854 : const char * NextLine();
1855 :
1856 : private:
1857 : static constexpr size_t kNumBytesPerLine = 48u;
1858 : static constexpr size_t kLineBufferSize = 64u + 1u; // PEM expects 64 characters wide and a null terminator at least.
1859 : static_assert(kLineBufferSize == (BASE64_ENCODED_LEN(kNumBytesPerLine) + 1), "Internal incoherence of library configuration!");
1860 :
1861 : enum State : int
1862 : {
1863 : kPrintHeader = 0,
1864 : kPrintBody = 1,
1865 : kPrintFooter = 2,
1866 : kDone = 3,
1867 : };
1868 :
1869 : const char * mEncodedElement; // "CERTIFICATE", "EC PUBLIC KEY", etc. Must be capitalized by caller.
1870 : ByteSpan mDerBytes;
1871 : State mState = State::kPrintHeader;
1872 : size_t mProcessedBytes = 0;
1873 : StringBuilder<kLineBufferSize> mStringBuilder{};
1874 : };
1875 :
1876 : // Utility class to take subject Key IDs (AKID/SKID) and convert them to DCL format ("A5:FF:00.....:DE:AD").
1877 : class KeyIdStringifier
1878 : {
1879 : public:
1880 9 : KeyIdStringifier() = default;
1881 :
1882 : /**
1883 : * @brief Returns the null-terminated string buffer owned by the class containing converted KeyID.
1884 : *
1885 : * LIFETIME NOTE: The last returned value from KeyIdToHex is valid until the next call.
1886 : *
1887 : * This is optimized for standard 20-byte AKID/SKID but works for any length, truncating very long ones.
1888 : *
1889 : * @param keyIdBuffer - buffer of bytes of the key ID.
1890 : * @return pointer to class-owned storage of a null-terminated string in DCL format.
1891 : */
1892 9 : const char * KeyIdToHex(ByteSpan keyIdBuffer)
1893 : {
1894 9 : mStringBuilder.Reset();
1895 9 : if (keyIdBuffer.empty())
1896 : {
1897 0 : mStringBuilder.Add("<EMPTY KEY ID>");
1898 0 : return mStringBuilder.c_str();
1899 : }
1900 :
1901 9 : mStringBuilder.AddFormat("%02X", keyIdBuffer[0]);
1902 180 : for (size_t i = 1; i < keyIdBuffer.size(); ++i)
1903 : {
1904 171 : mStringBuilder.Add(":");
1905 171 : mStringBuilder.AddFormat("%02X", keyIdBuffer[i]);
1906 : }
1907 :
1908 9 : return mStringBuilder.AddMarkerIfOverflow().c_str();
1909 : }
1910 :
1911 : private:
1912 : StringBuilder<(Crypto::kAuthorityKeyIdentifierLength * 3) + 1> mStringBuilder;
1913 : };
1914 :
1915 : /**
1916 : * @brief Checks for resigned version of the certificate in the list and returns it.
1917 : *
1918 : * The following conditions SHOULD be satisfied for the certificate to qualify as
1919 : * a resigned version of a reference certificate:
1920 : * - SKID of the candidate and the reference certificate should match.
1921 : * - SubjectDN of the candidate and the reference certificate should match.
1922 : *
1923 : * If no resigned version is found then reference certificate itself is returned.
1924 : *
1925 : * @param referenceCertificate A DER certificate.
1926 : * @param candidateCertificates A pointer to the list of DER Certificates, which should be searched
1927 : * for the resigned version of `referenceCertificate`.
1928 : * @param candidateCertificatesCount Number of certificates in the `candidateCertificates` list.
1929 : * @param outCertificate A reference to the certificate or it's resigned version if found.
1930 : * Note that it points to either `referenceCertificate` or one of
1931 : * `candidateCertificates`, but it doesn't copy data.
1932 : *
1933 : * @returns error if there is certificate parsing/format issue or CHIP_NO_ERROR otherwise.
1934 : **/
1935 : CHIP_ERROR ReplaceCertIfResignedCertFound(const ByteSpan & referenceCertificate, const ByteSpan * candidateCertificates,
1936 : size_t candidateCertificatesCount, ByteSpan & outCertificate);
1937 :
1938 : /**
1939 : * Defines DN attribute types that can include endocing of VID/PID parameters.
1940 : */
1941 : enum class DNAttrType
1942 : {
1943 : kUnspecified = 0,
1944 : kCommonName = 1,
1945 : kMatterVID = 2,
1946 : kMatterPID = 3,
1947 : };
1948 :
1949 : /**
1950 : * @struct AttestationCertVidPid
1951 : *
1952 : * @brief
1953 : * A data structure representing Attestation Certificate VID and PID attributes.
1954 : */
1955 : struct AttestationCertVidPid
1956 : {
1957 : Optional<VendorId> mVendorId;
1958 : Optional<uint16_t> mProductId;
1959 :
1960 620 : bool Initialized() const { return (mVendorId.HasValue() || mProductId.HasValue()); }
1961 : };
1962 :
1963 : /**
1964 : * @brief Extracts VID and PID attributes from the DN Attribute string.
1965 : * If attribute is not present the corresponding output value stays uninitialized.
1966 : *
1967 : * @return CHIP_ERROR_INVALID_ARGUMENT if wrong input is provided.
1968 : * CHIP_ERROR_WRONG_CERT_DN if encoding of kMatterVID and kMatterPID attributes is wrong.
1969 : * CHIP_NO_ERROR otherwise.
1970 : **/
1971 : CHIP_ERROR ExtractVIDPIDFromAttributeString(DNAttrType attrType, const ByteSpan & attr,
1972 : AttestationCertVidPid & vidpidFromMatterAttr, AttestationCertVidPid & vidpidFromCNAttr);
1973 :
1974 : /**
1975 : * @brief Extracts VID and PID attributes from the Subject DN of an X509 Certificate.
1976 : * If attribute is not present the corresponding output value stays uninitialized.
1977 : **/
1978 : CHIP_ERROR ExtractVIDPIDFromX509Cert(const ByteSpan & x509Cert, AttestationCertVidPid & vidpid);
1979 :
1980 : /**
1981 : * @brief The set of credentials needed to operate group message security with symmetric keys.
1982 : */
1983 : typedef struct GroupOperationalCredentials
1984 : {
1985 : /// Validity start time in microseconds since 2000-01-01T00:00:00 UTC ("the Epoch")
1986 : uint64_t start_time;
1987 : /// Session Id
1988 : uint16_t hash;
1989 : /// Operational group key
1990 : uint8_t encryption_key[Crypto::CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES];
1991 : /// Privacy key
1992 : uint8_t privacy_key[Crypto::CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES];
1993 : } GroupOperationalCredentials;
1994 :
1995 : /**
1996 : * @brief Opaque context used to protect a symmetric key. The key operations must
1997 : * be performed without exposing the protected key value.
1998 : */
1999 : class SymmetricKeyContext
2000 : {
2001 : public:
2002 : /**
2003 : * @brief Returns the symmetric key hash
2004 : *
2005 : * TODO: Replace GetKeyHash() with DeriveGroupSessionId(SymmetricKeyContext &, uint16_t & session_id)
2006 : *
2007 : * @return Group Key Hash
2008 : */
2009 : virtual uint16_t GetKeyHash() = 0;
2010 :
2011 11 : virtual ~SymmetricKeyContext() = default;
2012 : /**
2013 : * @brief Perform the message encryption as described in 4.7.2. (Security Processing of Outgoing Messages)
2014 : * @param[in] plaintext Outgoing message payload.
2015 : * @param[in] aad Additional data (message header contents)
2016 : * @param[in] nonce Nonce (Security Flags | Message Counter | Source Node ID)
2017 : * @param[out] mic Outgoing Message Integrity Check
2018 : * @param[out] ciphertext Outgoing encrypted payload. Must be at least as big as plaintext. The same buffer may be used both
2019 : * for ciphertext, and plaintext.
2020 : * @return CHIP_ERROR
2021 : */
2022 : virtual CHIP_ERROR MessageEncrypt(const ByteSpan & plaintext, const ByteSpan & aad, const ByteSpan & nonce,
2023 : MutableByteSpan & mic, MutableByteSpan & ciphertext) const = 0;
2024 : /**
2025 : * @brief Perform the message decryption as described in 4.7.3.(Security Processing of Incoming Messages)
2026 : * @param[in] ciphertext Incoming encrypted payload
2027 : * @param[in] aad Additional data (message header contents)
2028 : * @param[in] nonce Nonce (Security Flags | Message Counter | Source Node ID)
2029 : * @param[in] mic Incoming Message Integrity Check
2030 : * @param[out] plaintext Incoming message payload. Must be at least as big as ciphertext. The same buffer may be used both
2031 : * for plaintext, and ciphertext.
2032 : * @return CHIP_ERROR
2033 : */
2034 : virtual CHIP_ERROR MessageDecrypt(const ByteSpan & ciphertext, const ByteSpan & aad, const ByteSpan & nonce,
2035 : const ByteSpan & mic, MutableByteSpan & plaintext) const = 0;
2036 :
2037 : /**
2038 : * @brief Perform privacy encoding as described in 4.8.2. (Privacy Processing of Outgoing Messages)
2039 : * @param[in] input Message header to privacy encrypt
2040 : * @param[in] nonce Privacy Nonce = session_id | mic
2041 : * @param[out] output Message header obfuscated
2042 : * @return CHIP_ERROR
2043 : */
2044 : virtual CHIP_ERROR PrivacyEncrypt(const ByteSpan & input, const ByteSpan & nonce, MutableByteSpan & output) const = 0;
2045 :
2046 : /**
2047 : * @brief Perform privacy decoding as described in 4.8.3. (Privacy Processing of Incoming Messages)
2048 : * @param[in] input Message header to privacy decrypt
2049 : * @param[in] nonce Privacy Nonce = session_id | mic
2050 : * @param[out] output Message header deobfuscated
2051 : * @return CHIP_ERROR
2052 : */
2053 : virtual CHIP_ERROR PrivacyDecrypt(const ByteSpan & input, const ByteSpan & nonce, MutableByteSpan & output) const = 0;
2054 :
2055 : /**
2056 : * @brief Release resources such as dynamic memory used to allocate this instance of the SymmetricKeyContext
2057 : */
2058 : virtual void Release() = 0;
2059 : };
2060 :
2061 : /**
2062 : * @brief Derives the Operational Group Key using the Key Derivation Function (KDF) from the given epoch key.
2063 : * @param[in] epoch_key The epoch key. Must be CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES bytes length.
2064 : * @param[in] compressed_fabric_id The compressed fabric ID for the fabric (big endian byte string)
2065 : * @param[out] out_key Symmetric key used as the encryption key during message processing for group communication.
2066 : The buffer size must be at least CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES bytes length.
2067 : * @return Returns a CHIP_NO_ERROR on succcess, or CHIP_ERROR_INTERNAL if the provided key is invalid.
2068 : **/
2069 : CHIP_ERROR DeriveGroupOperationalKey(const ByteSpan & epoch_key, const ByteSpan & compressed_fabric_id, MutableByteSpan & out_key);
2070 :
2071 : /**
2072 : * @brief Derives the Group Session ID from a given operational group key using
2073 : * the Key Derivation Function (Group Key Hash)
2074 : * @param[in] operational_key The operational group key. Must be CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES bytes length.
2075 : * @param[out] session_id Output of the Group Key Hash
2076 : * @return Returns a CHIP_NO_ERROR on succcess, or CHIP_ERROR_INVALID_ARGUMENT if the provided key is invalid.
2077 : **/
2078 : CHIP_ERROR DeriveGroupSessionId(const ByteSpan & operational_key, uint16_t & session_id);
2079 :
2080 : /**
2081 : * @brief Derives the Privacy Group Key using the Key Derivation Function (KDF) from the given epoch key.
2082 : * @param[in] epoch_key The epoch key. Must be CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES bytes length.
2083 : * @param[out] out_key Symmetric key used as the privacy key during message processing for group communication.
2084 : * The buffer size must be at least CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES bytes length.
2085 : * @return Returns a CHIP_NO_ERROR on succcess, or CHIP_ERROR_INTERNAL if the provided key is invalid.
2086 : **/
2087 : CHIP_ERROR DeriveGroupPrivacyKey(const ByteSpan & epoch_key, MutableByteSpan & out_key);
2088 :
2089 : /**
2090 : * @brief Derives the complete set of credentials needed for group security.
2091 : *
2092 : * This function will derive the Encryption Key, Group Key Hash (Session Id), and Privacy Key
2093 : * for the given Epoch Key and Compressed Fabric Id.
2094 : * @param[in] epoch_key The epoch key. Must be CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES bytes length.
2095 : * @param[in] compressed_fabric_id The compressed fabric ID for the fabric (big endian byte string)
2096 : * @param[out] operational_credentials The set of Symmetric keys used during message processing for group communication.
2097 : * @return Returns a CHIP_NO_ERROR on succcess, or CHIP_ERROR_INTERNAL if the provided key is invalid.
2098 : **/
2099 : CHIP_ERROR DeriveGroupOperationalCredentials(const ByteSpan & epoch_key, const ByteSpan & compressed_fabric_id,
2100 : GroupOperationalCredentials & operational_credentials);
2101 : } // namespace Crypto
2102 : } // namespace chip
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