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/Optional.h>
34 : #include <lib/support/BufferReader.h>
35 : #include <lib/support/CodeUtils.h>
36 : #include <lib/support/SafePointerCast.h>
37 : #include <lib/support/Span.h>
38 :
39 : #include <stddef.h>
40 : #include <string.h>
41 :
42 : namespace chip {
43 : namespace Crypto {
44 :
45 : inline constexpr size_t kMax_x509_Certificate_Length = 600;
46 :
47 : inline constexpr size_t kP256_FE_Length = 32;
48 : inline constexpr size_t kP256_ECDSA_Signature_Length_Raw = (2 * kP256_FE_Length);
49 : inline constexpr size_t kP256_Point_Length = (2 * kP256_FE_Length + 1);
50 : inline constexpr size_t kSHA256_Hash_Length = 32;
51 : inline constexpr size_t kSHA1_Hash_Length = 20;
52 : inline constexpr size_t kSubjectKeyIdentifierLength = kSHA1_Hash_Length;
53 : inline constexpr size_t kAuthorityKeyIdentifierLength = kSHA1_Hash_Length;
54 : inline constexpr size_t kMaxCertificateSerialNumberLength = 20;
55 : inline constexpr size_t kMaxCertificateDistinguishedNameLength = 200;
56 : inline constexpr size_t kMaxCRLDistributionPointURLLength = 100;
57 :
58 : inline constexpr char kValidCDPURIHttpPrefix[] = "http://";
59 : inline constexpr char kValidCDPURIHttpsPrefix[] = "https://";
60 :
61 : inline constexpr size_t CHIP_CRYPTO_GROUP_SIZE_BYTES = kP256_FE_Length;
62 : inline constexpr size_t CHIP_CRYPTO_PUBLIC_KEY_SIZE_BYTES = kP256_Point_Length;
63 :
64 : inline constexpr size_t CHIP_CRYPTO_AEAD_MIC_LENGTH_BYTES = 16;
65 : inline constexpr size_t CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES = 16;
66 :
67 : inline constexpr size_t kMax_ECDH_Secret_Length = kP256_FE_Length;
68 : inline constexpr size_t kMax_ECDSA_Signature_Length = kP256_ECDSA_Signature_Length_Raw;
69 : inline constexpr size_t kMAX_FE_Length = kP256_FE_Length;
70 : inline constexpr size_t kMAX_Point_Length = kP256_Point_Length;
71 : inline constexpr size_t kMAX_Hash_Length = kSHA256_Hash_Length;
72 :
73 : // Minimum required CSR length buffer length is relatively small since it's a single
74 : // P256 key and no metadata/extensions are expected to be honored by the CA.
75 : inline constexpr size_t kMIN_CSR_Buffer_Size = 255;
76 :
77 : [[deprecated("This constant is no longer used by common code and should be replaced by kMIN_CSR_Buffer_Size. Checks that a CSR is "
78 : "<= kMAX_CSR_Buffer_size must be updated. This remains to keep valid buffers working from previous public API "
79 : "usage.")]] constexpr size_t kMAX_CSR_Buffer_Size = 255;
80 :
81 : inline constexpr size_t CHIP_CRYPTO_HASH_LEN_BYTES = kSHA256_Hash_Length;
82 :
83 : inline constexpr size_t kSpake2p_Min_PBKDF_Salt_Length = 16;
84 : inline constexpr size_t kSpake2p_Max_PBKDF_Salt_Length = 32;
85 : inline constexpr uint32_t kSpake2p_Min_PBKDF_Iterations = 1000;
86 : inline constexpr uint32_t kSpake2p_Max_PBKDF_Iterations = 100000;
87 :
88 : inline constexpr size_t kP256_PrivateKey_Length = CHIP_CRYPTO_GROUP_SIZE_BYTES;
89 : inline constexpr size_t kP256_PublicKey_Length = CHIP_CRYPTO_PUBLIC_KEY_SIZE_BYTES;
90 :
91 : inline constexpr size_t kAES_CCM128_Key_Length = 128u / 8u;
92 : inline constexpr size_t kAES_CCM128_Block_Length = kAES_CCM128_Key_Length;
93 : inline constexpr size_t kAES_CCM128_Nonce_Length = 13;
94 : inline constexpr size_t kAES_CCM128_Tag_Length = 16;
95 : inline constexpr size_t kHMAC_CCM128_Key_Length = 128u / 8u;
96 :
97 : inline constexpr size_t CHIP_CRYPTO_AEAD_NONCE_LENGTH_BYTES = kAES_CCM128_Nonce_Length;
98 :
99 : /* These sizes are hardcoded here to remove header dependency on underlying crypto library
100 : * in a public interface file. The validity of these sizes is verified by static_assert in
101 : * the implementation files.
102 : */
103 : inline constexpr size_t kMAX_Spake2p_Context_Size = 1024;
104 : inline constexpr size_t kMAX_P256Keypair_Context_Size = 512;
105 :
106 : inline constexpr size_t kEmitDerIntegerWithoutTagOverhead = 1; // 1 sign stuffer
107 : inline constexpr size_t kEmitDerIntegerOverhead = 3; // Tag + Length byte + 1 sign stuffer
108 :
109 : inline constexpr size_t kMAX_Hash_SHA256_Context_Size = CHIP_CONFIG_SHA256_CONTEXT_SIZE;
110 :
111 : inline constexpr size_t kSpake2p_WS_Length = kP256_FE_Length + 8;
112 : inline constexpr size_t kSpake2p_VerifierSerialized_Length = kP256_FE_Length + kP256_Point_Length;
113 :
114 : inline constexpr char kVIDPrefixForCNEncoding[] = "Mvid:";
115 : inline constexpr char kPIDPrefixForCNEncoding[] = "Mpid:";
116 : inline constexpr size_t kVIDandPIDHexLength = sizeof(uint16_t) * 2;
117 : inline constexpr size_t kMax_CommonNameAttr_Length = 64;
118 :
119 : /*
120 : * Overhead to encode a raw ECDSA signature in X9.62 format in ASN.1 DER
121 : *
122 : * Ecdsa-Sig-Value ::= SEQUENCE {
123 : * r INTEGER,
124 : * s INTEGER
125 : * }
126 : *
127 : * --> SEQUENCE, universal constructed tag (0x30), length over 2 bytes, up to 255 (to support future larger sizes up to 512 bits)
128 : * -> SEQ_OVERHEAD = 3 bytes
129 : * --> INTEGER, universal primitive tag (0x02), length over 1 byte, one extra byte worst case
130 : * over max for 0x00 when MSB is set.
131 : * -> INT_OVERHEAD = 3 bytes
132 : *
133 : * There is 1 sequence of 2 integers. Overhead is SEQ_OVERHEAD + (2 * INT_OVERHEAD) = 3 + (2 * 3) = 9.
134 : */
135 : inline constexpr size_t kMax_ECDSA_X9Dot62_Asn1_Overhead = 9;
136 : inline constexpr size_t kMax_ECDSA_Signature_Length_Der = kMax_ECDSA_Signature_Length + kMax_ECDSA_X9Dot62_Asn1_Overhead;
137 :
138 : static_assert(kMax_ECDH_Secret_Length >= kP256_FE_Length, "ECDH shared secret is too short for crypto suite");
139 : static_assert(kMax_ECDSA_Signature_Length >= kP256_ECDSA_Signature_Length_Raw,
140 : "ECDSA signature buffer length is too short for crypto suite");
141 :
142 : inline constexpr size_t kCompressedFabricIdentifierSize = 8;
143 :
144 : /**
145 : * Spake2+ parameters for P256
146 : * Defined in https://www.ietf.org/id/draft-bar-cfrg-spake2plus-01.html#name-ciphersuites
147 : */
148 : const uint8_t spake2p_M_p256[] = {
149 : 0x04, 0x88, 0x6e, 0x2f, 0x97, 0xac, 0xe4, 0x6e, 0x55, 0xba, 0x9d, 0xd7, 0x24, 0x25, 0x79, 0xf2, 0x99,
150 : 0x3b, 0x64, 0xe1, 0x6e, 0xf3, 0xdc, 0xab, 0x95, 0xaf, 0xd4, 0x97, 0x33, 0x3d, 0x8f, 0xa1, 0x2f, 0x5f,
151 : 0xf3, 0x55, 0x16, 0x3e, 0x43, 0xce, 0x22, 0x4e, 0x0b, 0x0e, 0x65, 0xff, 0x02, 0xac, 0x8e, 0x5c, 0x7b,
152 : 0xe0, 0x94, 0x19, 0xc7, 0x85, 0xe0, 0xca, 0x54, 0x7d, 0x55, 0xa1, 0x2e, 0x2d, 0x20,
153 : };
154 : const uint8_t spake2p_N_p256[] = {
155 : 0x04, 0xd8, 0xbb, 0xd6, 0xc6, 0x39, 0xc6, 0x29, 0x37, 0xb0, 0x4d, 0x99, 0x7f, 0x38, 0xc3, 0x77, 0x07,
156 : 0x19, 0xc6, 0x29, 0xd7, 0x01, 0x4d, 0x49, 0xa2, 0x4b, 0x4f, 0x98, 0xba, 0xa1, 0x29, 0x2b, 0x49, 0x07,
157 : 0xd6, 0x0a, 0xa6, 0xbf, 0xad, 0xe4, 0x50, 0x08, 0xa6, 0x36, 0x33, 0x7f, 0x51, 0x68, 0xc6, 0x4d, 0x9b,
158 : 0xd3, 0x60, 0x34, 0x80, 0x8c, 0xd5, 0x64, 0x49, 0x0b, 0x1e, 0x65, 0x6e, 0xdb, 0xe7,
159 : };
160 :
161 : /**
162 : * Spake2+ state machine to ensure proper execution of the protocol.
163 : */
164 : enum class CHIP_SPAKE2P_STATE : uint8_t
165 : {
166 : PREINIT = 0, // Before any initialization
167 : INIT, // First initialization
168 : STARTED, // Prover & Verifier starts
169 : R1, // Round one complete
170 : R2, // Round two complete
171 : KC, // Key confirmation complete
172 : };
173 :
174 : /**
175 : * Spake2+ role.
176 : */
177 : enum class CHIP_SPAKE2P_ROLE : uint8_t
178 : {
179 : VERIFIER = 0, // Accessory
180 : PROVER = 1, // Commissioner
181 : };
182 :
183 : enum class SupportedECPKeyTypes : uint8_t
184 : {
185 : ECP256R1 = 0,
186 : };
187 :
188 : enum class ECPKeyTarget : uint8_t
189 : {
190 : ECDH = 0,
191 : ECDSA = 1,
192 : };
193 :
194 : /** @brief Safely clears the first `len` bytes of memory area `buf`.
195 : * @param buf Pointer to a memory buffer holding secret data that must be cleared.
196 : * @param len Specifies secret data size in bytes.
197 : **/
198 : void ClearSecretData(uint8_t * buf, size_t len);
199 :
200 : /**
201 : * Helper for clearing a C array which auto-deduces the size.
202 : */
203 : template <size_t N>
204 411446 : void ClearSecretData(uint8_t (&buf)[N])
205 : {
206 411446 : ClearSecretData(buf, N);
207 411446 : }
208 :
209 : /**
210 : * @brief Constant-time buffer comparison
211 : *
212 : * This function implements constant time memcmp. It's good practice
213 : * to use constant time functions for cryptographic functions.
214 : *
215 : * @param a Pointer to first buffer
216 : * @param b Pointer to Second buffer
217 : * @param n Number of bytes to compare
218 : * @return true if `n` first bytes of both buffers are equal, false otherwise
219 : */
220 : bool IsBufferContentEqualConstantTime(const void * a, const void * b, size_t n);
221 :
222 : template <typename Sig>
223 : class ECPKey
224 : {
225 : protected:
226 : // This base type can't be copied / assigned directly.
227 : // Sub-types should be either uncopyable or final.
228 7896 : ECPKey() = default;
229 : ECPKey(const ECPKey &) = default;
230 1348 : ECPKey & operator=(const ECPKey &) = default;
231 :
232 : public:
233 7896 : virtual ~ECPKey() = default;
234 :
235 : virtual SupportedECPKeyTypes Type() const = 0;
236 : virtual size_t Length() const = 0;
237 : virtual bool IsUncompressed() const = 0;
238 : virtual operator const uint8_t *() const = 0;
239 : virtual operator uint8_t *() = 0;
240 : virtual const uint8_t * ConstBytes() const = 0;
241 : virtual uint8_t * Bytes() = 0;
242 :
243 676 : virtual bool Matches(const ECPKey<Sig> & other) const
244 : {
245 1352 : return (this->Length() == other.Length()) &&
246 1352 : IsBufferContentEqualConstantTime(this->ConstBytes(), other.ConstBytes(), this->Length());
247 : }
248 :
249 : virtual CHIP_ERROR ECDSA_validate_msg_signature(const uint8_t * msg, const size_t msg_length, const Sig & signature) const = 0;
250 : virtual CHIP_ERROR ECDSA_validate_hash_signature(const uint8_t * hash, const size_t hash_length,
251 : const Sig & signature) const = 0;
252 : };
253 :
254 : /**
255 : * @brief Helper class for holding sensitive data that should be erased from memory after use.
256 : *
257 : * The sensitive data buffer is a variable-length, fixed-capacity buffer class that securely erases
258 : * the contents of a buffer when the buffer is destroyed.
259 : */
260 : template <size_t kCapacity>
261 : class SensitiveDataBuffer
262 : {
263 : public:
264 3123 : ~SensitiveDataBuffer()
265 : {
266 : // Sanitize after use
267 3123 : ClearSecretData(mBytes);
268 3123 : }
269 :
270 : SensitiveDataBuffer & operator=(const SensitiveDataBuffer & other)
271 : {
272 : // Guard self assignment
273 : if (this == &other)
274 : return *this;
275 :
276 : ClearSecretData(mBytes);
277 : SetLength(other.Length());
278 : ::memcpy(Bytes(), other.ConstBytes(), other.Length());
279 : return *this;
280 : }
281 :
282 : /**
283 : * @brief Set current length of the buffer
284 : * @return Error if new length is exceeds capacity of the buffer
285 : */
286 3876 : CHIP_ERROR SetLength(size_t length)
287 : {
288 3876 : VerifyOrReturnError(length <= kCapacity, CHIP_ERROR_INVALID_ARGUMENT);
289 3876 : mLength = length;
290 3876 : return CHIP_NO_ERROR;
291 : }
292 :
293 : /**
294 : * @brief Returns current length of the buffer
295 : */
296 4465 : size_t Length() const { return mLength; }
297 :
298 : /**
299 : * @brief Returns non-const pointer to start of the underlying buffer
300 : */
301 5310 : uint8_t * Bytes() { return &mBytes[0]; }
302 :
303 : /**
304 : * @brief Returns const pointer to start of the underlying buffer
305 : */
306 6348 : const uint8_t * ConstBytes() const { return &mBytes[0]; }
307 :
308 : /**
309 : * @brief Constructs span from the underlying buffer
310 : */
311 21 : ByteSpan Span() const { return ByteSpan(ConstBytes(), Length()); }
312 :
313 : /**
314 : * @brief Returns capacity of the buffer
315 : */
316 1710 : static constexpr size_t Capacity() { return kCapacity; }
317 :
318 : private:
319 : uint8_t mBytes[kCapacity];
320 : size_t mLength = 0;
321 : };
322 :
323 : /**
324 : * @brief Helper class for holding fixed-sized sensitive data that should be erased from memory after use.
325 : *
326 : * The sensitive data buffer is a fixed-length, fixed-capacity buffer class that securely erases
327 : * the contents of a buffer when the buffer is destroyed.
328 : */
329 : template <size_t kCapacity>
330 : class SensitiveDataFixedBuffer
331 : {
332 : public:
333 : SensitiveDataFixedBuffer() = default;
334 :
335 : constexpr explicit SensitiveDataFixedBuffer(const uint8_t (&rawValue)[kCapacity])
336 : {
337 : memcpy(&mBytes[0], &rawValue[0], kCapacity);
338 : }
339 :
340 0 : constexpr explicit SensitiveDataFixedBuffer(const FixedByteSpan<kCapacity> & value)
341 : {
342 0 : memcpy(&mBytes[0], value.data(), kCapacity);
343 0 : }
344 :
345 135111 : ~SensitiveDataFixedBuffer()
346 : {
347 : // Sanitize after use
348 135111 : ClearSecretData(mBytes);
349 135111 : }
350 :
351 : /**
352 : * @brief Returns fixed length of the buffer
353 : */
354 : constexpr size_t Length() const { return kCapacity; }
355 :
356 : /**
357 : * @brief Returns non-const pointer to start of the underlying buffer
358 : */
359 1333 : uint8_t * Bytes() { return &mBytes[0]; }
360 :
361 : /**
362 : * @brief Returns const pointer to start of the underlying buffer
363 : */
364 : const uint8_t * ConstBytes() const { return &mBytes[0]; }
365 :
366 : /**
367 : * @brief Constructs fixed span from the underlying buffer
368 : */
369 0 : FixedByteSpan<kCapacity> Span() const { return FixedByteSpan<kCapacity>(mBytes); }
370 :
371 : /**
372 : * @brief Returns capacity of the buffer
373 : */
374 1318 : static constexpr size_t Capacity() { return kCapacity; }
375 :
376 : private:
377 : uint8_t mBytes[kCapacity];
378 : };
379 :
380 : using P256ECDSASignature = SensitiveDataBuffer<kMax_ECDSA_Signature_Length>;
381 : using P256ECDHDerivedSecret = SensitiveDataBuffer<kMax_ECDH_Secret_Length>;
382 :
383 : using IdentityProtectionKey = SensitiveDataFixedBuffer<CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES>;
384 : using IdentityProtectionKeySpan = FixedByteSpan<Crypto::CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES>;
385 :
386 : using AttestationChallenge = SensitiveDataFixedBuffer<CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES>;
387 :
388 : class P256PublicKey final // final due to being copyable
389 : : public ECPKey<P256ECDSASignature>
390 : {
391 : public:
392 7202 : P256PublicKey() = default;
393 :
394 : template <size_t N>
395 : constexpr P256PublicKey(const uint8_t (&raw_value)[N])
396 : {
397 : static_assert(N == kP256_PublicKey_Length, "Can only array-initialize from proper bounds");
398 : memcpy(&bytes[0], &raw_value[0], N);
399 : }
400 :
401 : template <size_t N>
402 625 : constexpr P256PublicKey(const FixedByteSpan<N> & value)
403 625 : {
404 : static_assert(N == kP256_PublicKey_Length, "Can only initialize from proper sized byte span");
405 625 : memcpy(&bytes[0], value.data(), N);
406 625 : }
407 :
408 : template <size_t N>
409 799 : P256PublicKey & operator=(const FixedByteSpan<N> & value)
410 : {
411 : static_assert(N == kP256_PublicKey_Length, "Can only initialize from proper sized byte span");
412 799 : memcpy(&bytes[0], value.data(), N);
413 799 : return *this;
414 : }
415 :
416 3625 : SupportedECPKeyTypes Type() const override { return SupportedECPKeyTypes::ECP256R1; }
417 13903 : size_t Length() const override { return kP256_PublicKey_Length; }
418 4804 : operator uint8_t *() override { return bytes; }
419 2801 : operator const uint8_t *() const override { return bytes; }
420 2759 : const uint8_t * ConstBytes() const override { return &bytes[0]; }
421 17 : uint8_t * Bytes() override { return &bytes[0]; }
422 681 : bool IsUncompressed() const override
423 : {
424 681 : constexpr uint8_t kUncompressedPointMarker = 0x04;
425 : // SEC1 definition of an uncompressed point is (0x04 || X || Y) where X and Y are
426 : // raw zero-padded big-endian large integers of the group size.
427 681 : return (Length() == ((kP256_FE_Length * 2) + 1)) && (ConstBytes()[0] == kUncompressedPointMarker);
428 : }
429 :
430 : CHIP_ERROR ECDSA_validate_msg_signature(const uint8_t * msg, size_t msg_length,
431 : const P256ECDSASignature & signature) const override;
432 : CHIP_ERROR ECDSA_validate_hash_signature(const uint8_t * hash, size_t hash_length,
433 : const P256ECDSASignature & signature) const override;
434 :
435 : private:
436 : uint8_t bytes[kP256_PublicKey_Length];
437 : };
438 :
439 : template <typename PK, typename Secret, typename Sig>
440 : class ECPKeypair
441 : {
442 : protected:
443 : // This base type can't be copied / assigned directly.
444 : // Sub-types should be either uncopyable or final.
445 1197 : ECPKeypair() = default;
446 : ECPKeypair(const ECPKeypair &) = default;
447 : ECPKeypair & operator=(const ECPKeypair &) = default;
448 :
449 : public:
450 1489 : virtual ~ECPKeypair() = default;
451 :
452 : /** @brief Generate a new Certificate Signing Request (CSR).
453 : * @param csr Newly generated CSR in DER format
454 : * @param csr_length The caller provides the length of input buffer (csr). The function returns the actual length of generated
455 : *CSR.
456 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
457 : **/
458 : virtual CHIP_ERROR NewCertificateSigningRequest(uint8_t * csr, size_t & csr_length) const = 0;
459 :
460 : /**
461 : * @brief A function to sign a msg using ECDSA
462 : * @param msg Message that needs to be signed
463 : * @param msg_length Length of message
464 : * @param out_signature Buffer that will hold the output signature. The signature consists of: 2 EC elements (r and s),
465 : * in raw <r,s> point form (see SEC1).
466 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
467 : **/
468 : virtual CHIP_ERROR ECDSA_sign_msg(const uint8_t * msg, size_t msg_length, Sig & out_signature) const = 0;
469 :
470 : /** @brief A function to derive a shared secret using ECDH
471 : * @param remote_public_key Public key of remote peer with which we are trying to establish secure channel. remote_public_key is
472 : * ASN.1 DER encoded as padded big-endian field elements as described in SEC 1: Elliptic Curve Cryptography
473 : * [https://www.secg.org/sec1-v2.pdf]
474 : * @param out_secret Buffer to write out secret into. This is a byte array representing the x coordinate of the shared secret.
475 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
476 : **/
477 : virtual CHIP_ERROR ECDH_derive_secret(const PK & remote_public_key, Secret & out_secret) const = 0;
478 :
479 : virtual const PK & Pubkey() const = 0;
480 : };
481 :
482 : struct alignas(size_t) P256KeypairContext
483 : {
484 : uint8_t mBytes[kMAX_P256Keypair_Context_Size];
485 : };
486 :
487 : /**
488 : * A serialized P256 key pair is the concatenation of the public and private keys, in that order.
489 : */
490 : using P256SerializedKeypair = SensitiveDataBuffer<kP256_PublicKey_Length + kP256_PrivateKey_Length>;
491 :
492 : class P256KeypairBase : public ECPKeypair<P256PublicKey, P256ECDHDerivedSecret, P256ECDSASignature>
493 : {
494 : protected:
495 : // This base type can't be copied / assigned directly.
496 : // Sub-types should be either uncopyable or final.
497 1197 : P256KeypairBase() = default;
498 : P256KeypairBase(const P256KeypairBase &) = default;
499 : P256KeypairBase & operator=(const P256KeypairBase &) = default;
500 :
501 : public:
502 : /**
503 : * @brief Initialize the keypair.
504 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
505 : **/
506 : virtual CHIP_ERROR Initialize(ECPKeyTarget key_target) = 0;
507 :
508 : /**
509 : * @brief Serialize the keypair.
510 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
511 : **/
512 : virtual CHIP_ERROR Serialize(P256SerializedKeypair & output) const = 0;
513 :
514 : /**
515 : * @brief Deserialize the keypair.
516 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
517 : **/
518 : virtual CHIP_ERROR Deserialize(P256SerializedKeypair & input) = 0;
519 : };
520 :
521 : class P256Keypair : public P256KeypairBase
522 : {
523 : public:
524 1197 : P256Keypair() = default;
525 : ~P256Keypair() override;
526 :
527 : // P256Keypair can't be copied / assigned.
528 : P256Keypair(const P256Keypair &) = delete;
529 : P256Keypair & operator=(const P256Keypair &) = delete;
530 :
531 : /**
532 : * @brief Initialize the keypair.
533 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
534 : **/
535 : CHIP_ERROR Initialize(ECPKeyTarget key_target) override;
536 :
537 : /**
538 : * @brief Serialize the keypair.
539 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
540 : **/
541 : CHIP_ERROR Serialize(P256SerializedKeypair & output) const override;
542 :
543 : /**
544 : * @brief Deserialize the keypair.
545 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
546 : **/
547 : CHIP_ERROR Deserialize(P256SerializedKeypair & input) override;
548 :
549 : /**
550 : * @brief Generate a new Certificate Signing Request (CSR).
551 : * @param csr Newly generated CSR in DER format
552 : * @param csr_length The caller provides the length of input buffer (csr). The function returns the actual length of generated
553 : *CSR.
554 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
555 : **/
556 : CHIP_ERROR NewCertificateSigningRequest(uint8_t * csr, size_t & csr_length) const override;
557 :
558 : /**
559 : * @brief A function to sign a msg using ECDSA
560 : * @param msg Message that needs to be signed
561 : * @param msg_length Length of message
562 : * @param out_signature Buffer that will hold the output signature. The signature consists of: 2 EC elements (r and s),
563 : * in raw <r,s> point form (see SEC1).
564 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
565 : **/
566 : CHIP_ERROR ECDSA_sign_msg(const uint8_t * msg, size_t msg_length, P256ECDSASignature & out_signature) const override;
567 :
568 : /**
569 : * @brief A function to derive a shared secret using ECDH
570 : *
571 : * This implements the CHIP_Crypto_ECDH(PrivateKey myPrivateKey, PublicKey theirPublicKey) cryptographic primitive
572 : * from the specification, using this class's private key from `mKeypair` as `myPrivateKey` and the remote
573 : * public key from `remote_public_key` as `theirPublicKey`.
574 : *
575 : * @param remote_public_key Public key of remote peer with which we are trying to establish secure channel. remote_public_key is
576 : * ASN.1 DER encoded as padded big-endian field elements as described in SEC 1: Elliptic Curve Cryptography
577 : * [https://www.secg.org/sec1-v2.pdf]
578 : * @param out_secret Buffer to write out secret into. This is a byte array representing the x coordinate of the shared secret.
579 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
580 : **/
581 : CHIP_ERROR ECDH_derive_secret(const P256PublicKey & remote_public_key, P256ECDHDerivedSecret & out_secret) const override;
582 :
583 : /** @brief Return public key for the keypair.
584 : **/
585 978 : const P256PublicKey & Pubkey() const override { return mPublicKey; }
586 :
587 : /** Release resources associated with this key pair */
588 : void Clear();
589 :
590 : protected:
591 : P256PublicKey mPublicKey;
592 : mutable P256KeypairContext mKeypair;
593 : bool mInitialized = false;
594 : };
595 :
596 : /**
597 : * @brief Platform-specific symmetric key handle
598 : *
599 : * The class represents a key used by the Matter stack either in the form of raw key material or key
600 : * reference, depending on the platform. To achieve that, it contains an opaque context that can be
601 : * cast to a concrete representation used by the given platform.
602 : *
603 : * @note SymmetricKeyHandle is an abstract class to force child classes for each key handle type.
604 : * SymmetricKeyHandle class implements all the necessary components for handles.
605 : */
606 : template <size_t ContextSize>
607 : class SymmetricKeyHandle
608 : {
609 : public:
610 : SymmetricKeyHandle(const SymmetricKeyHandle &) = delete;
611 : SymmetricKeyHandle(SymmetricKeyHandle &&) = delete;
612 : void operator=(const SymmetricKeyHandle &) = delete;
613 : void operator=(SymmetricKeyHandle &&) = delete;
614 :
615 : /**
616 : * @brief Get internal context cast to the desired key representation
617 : */
618 : template <class T>
619 19247 : const T & As() const
620 : {
621 19247 : return *SafePointerCast<const T *>(&mContext);
622 : }
623 :
624 : /**
625 : * @brief Get internal context cast to the desired, mutable key representation
626 : */
627 : template <class T>
628 6046 : T & AsMutable()
629 : {
630 6046 : return *SafePointerCast<T *>(&mContext);
631 : }
632 :
633 : protected:
634 270388 : SymmetricKeyHandle() = default;
635 270388 : ~SymmetricKeyHandle() { ClearSecretData(mContext.mOpaque); }
636 :
637 : private:
638 : struct alignas(uintptr_t) OpaqueContext
639 : {
640 : uint8_t mOpaque[ContextSize] = {};
641 : } mContext;
642 : };
643 :
644 : using Symmetric128BitsKeyByteArray = uint8_t[CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES];
645 :
646 : /**
647 : * @brief Platform-specific 128-bit symmetric key handle
648 : */
649 : class Symmetric128BitsKeyHandle : public SymmetricKeyHandle<CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES>
650 : {
651 : };
652 :
653 : /**
654 : * @brief Platform-specific 128-bit AES key handle
655 : */
656 : class Aes128KeyHandle final : public Symmetric128BitsKeyHandle
657 : {
658 : };
659 :
660 : /**
661 : * @brief Platform-specific 128-bit HMAC key handle
662 : */
663 : class Hmac128KeyHandle final : public Symmetric128BitsKeyHandle
664 : {
665 : };
666 :
667 : /**
668 : * @brief Platform-specific HKDF key handle
669 : */
670 : class HkdfKeyHandle final : public SymmetricKeyHandle<CHIP_CONFIG_HKDF_KEY_HANDLE_CONTEXT_SIZE>
671 : {
672 : };
673 :
674 : /**
675 : * @brief Convert a raw ECDSA signature to ASN.1 signature (per X9.62) as used by TLS libraries.
676 : *
677 : * Errors are:
678 : * - CHIP_ERROR_INVALID_ARGUMENT on any argument being invalid (e.g. nullptr), wrong sizes,
679 : * wrong or unsupported format,
680 : * - CHIP_ERROR_BUFFER_TOO_SMALL on running out of space at runtime.
681 : * - CHIP_ERROR_INTERNAL on any unexpected processing error.
682 : *
683 : * @param[in] fe_length_bytes Field Element length in bytes (e.g. 32 for P256 curve)
684 : * @param[in] raw_sig Raw signature of <r,s> concatenated
685 : * @param[out] out_asn1_sig ASN.1 DER signature format output buffer. Size must have space for at least
686 : * kMax_ECDSA_X9Dot62_Asn1_Overhead. On CHIP_NO_ERROR, the out_asn1_sig buffer will be re-assigned
687 : * to have the correct size based on variable-length output.
688 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
689 : */
690 : CHIP_ERROR EcdsaRawSignatureToAsn1(size_t fe_length_bytes, const ByteSpan & raw_sig, MutableByteSpan & out_asn1_sig);
691 :
692 : /**
693 : * @brief Convert an ASN.1 DER signature (per X9.62) as used by TLS libraries to SEC1 raw format
694 : *
695 : * Errors are:
696 : * - CHIP_ERROR_INVALID_ARGUMENT on any argument being invalid (e.g. nullptr), wrong sizes,
697 : * wrong or unsupported format,
698 : * - CHIP_ERROR_BUFFER_TOO_SMALL on running out of space at runtime.
699 : * - CHIP_ERROR_INTERNAL on any unexpected processing error.
700 : *
701 : * @param[in] fe_length_bytes Field Element length in bytes (e.g. 32 for P256 curve)
702 : * @param[in] asn1_sig ASN.1 DER signature input
703 : * @param[out] out_raw_sig Raw signature of <r,s> concatenated format output buffer. Size must be at
704 : * least >= `2 * fe_length_bytes`. On CHIP_NO_ERROR, the out_raw_sig buffer will be re-assigned
705 : * to have the correct size (2 * fe_length_bytes).
706 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
707 : */
708 : CHIP_ERROR EcdsaAsn1SignatureToRaw(size_t fe_length_bytes, const ByteSpan & asn1_sig, MutableByteSpan & out_raw_sig);
709 :
710 : /**
711 : * @brief Utility to read a length field after a tag in a DER-encoded stream.
712 : * @param[in] reader Reader instance from which the input will be read
713 : * @param[out] length Length of the following element read from the stream
714 : * @return CHIP_ERROR_INVALID_ARGUMENT or CHIP_ERROR_BUFFER_TOO_SMALL on error, CHIP_NO_ERROR otherwise
715 : */
716 : CHIP_ERROR ReadDerLength(chip::Encoding::LittleEndian::Reader & reader, size_t & length);
717 :
718 : /**
719 : * @brief Utility to emit a DER-encoded INTEGER given a raw unsigned large integer
720 : * in big-endian order. The `out_der_integer` span is updated to reflect the final
721 : * variable length, including tag and length, and must have at least `kEmitDerIntegerOverhead`
722 : * extra space in addition to the `raw_integer.size()`.
723 : * @param[in] raw_integer Bytes of a large unsigned integer in big-endian, possibly including leading zeroes
724 : * @param[out] out_der_integer Buffer to receive the DER-encoded integer
725 : * @return Returns CHIP_ERROR_INVALID_ARGUMENT or CHIP_ERROR_BUFFER_TOO_SMALL on error, CHIP_NO_ERROR otherwise.
726 : */
727 : CHIP_ERROR ConvertIntegerRawToDer(const ByteSpan & raw_integer, MutableByteSpan & out_der_integer);
728 :
729 : /**
730 : * @brief Utility to emit a DER-encoded INTEGER given a raw unsigned large integer
731 : * in big-endian order. The `out_der_integer` span is updated to reflect the final
732 : * variable length, excluding tag and length, and must have at least `kEmitDerIntegerWithoutTagOverhead`
733 : * extra space in addition to the `raw_integer.size()`.
734 : * @param[in] raw_integer Bytes of a large unsigned integer in big-endian, possibly including leading zeroes
735 : * @param[out] out_der_integer Buffer to receive the DER-encoded integer
736 : * @return Returns CHIP_ERROR_INVALID_ARGUMENT or CHIP_ERROR_BUFFER_TOO_SMALL on error, CHIP_NO_ERROR otherwise.
737 : */
738 : CHIP_ERROR ConvertIntegerRawToDerWithoutTag(const ByteSpan & raw_integer, MutableByteSpan & out_der_integer);
739 :
740 : /**
741 : * @brief A function that implements AES-CCM encryption
742 : *
743 : * This implements the CHIP_Crypto_AEAD_GenerateEncrypt() cryptographic primitive
744 : * from the specification. For an empty plaintext, the user of the API can provide
745 : * an empty string, or a nullptr, and provide plaintext_length as 0. The output buffer,
746 : * ciphertext can also be an empty string, or a nullptr for this case.
747 : *
748 : * @param plaintext Plaintext to encrypt
749 : * @param plaintext_length Length of plain_text
750 : * @param aad Additional authentication data
751 : * @param aad_length Length of additional authentication data
752 : * @param key Encryption key
753 : * @param nonce Encryption nonce
754 : * @param nonce_length Length of encryption nonce
755 : * @param ciphertext Buffer to write ciphertext into. Caller must ensure this is large enough to hold the ciphertext
756 : * @param tag Buffer to write tag into. Caller must ensure this is large enough to hold the tag
757 : * @param tag_length Expected length of tag
758 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
759 : * */
760 : CHIP_ERROR AES_CCM_encrypt(const uint8_t * plaintext, size_t plaintext_length, const uint8_t * aad, size_t aad_length,
761 : const Aes128KeyHandle & key, const uint8_t * nonce, size_t nonce_length, uint8_t * ciphertext,
762 : uint8_t * tag, size_t tag_length);
763 :
764 : /**
765 : * @brief A function that implements AES-CCM decryption
766 : *
767 : * This implements the CHIP_Crypto_AEAD_DecryptVerify() cryptographic primitive
768 : * from the specification. For an empty ciphertext, the user of the API can provide
769 : * an empty string, or a nullptr, and provide ciphertext_length as 0. The output buffer,
770 : * plaintext can also be an empty string, or a nullptr for this case.
771 : *
772 : * @param ciphertext Ciphertext to decrypt
773 : * @param ciphertext_length Length of ciphertext
774 : * @param aad Additional authentical data.
775 : * @param aad_length Length of additional authentication data
776 : * @param tag Tag to use to decrypt
777 : * @param tag_length Length of tag
778 : * @param key Decryption key
779 : * @param nonce Encryption nonce
780 : * @param nonce_length Length of encryption nonce
781 : * @param plaintext Buffer to write plaintext into
782 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
783 : **/
784 : CHIP_ERROR AES_CCM_decrypt(const uint8_t * ciphertext, size_t ciphertext_length, const uint8_t * aad, size_t aad_length,
785 : const uint8_t * tag, size_t tag_length, const Aes128KeyHandle & key, const uint8_t * nonce,
786 : size_t nonce_length, uint8_t * plaintext);
787 :
788 : /**
789 : * @brief A function that implements AES-CTR encryption/decryption
790 : *
791 : * This implements the AES-CTR-Encrypt/Decrypt() cryptographic primitives per sections
792 : * 3.7.1 and 3.7.2 of the specification. For an empty input, the user of the API
793 : * can provide an empty string, or a nullptr, and provide input as 0.
794 : * The output buffer can also be an empty string, or a nullptr for this case.
795 : *
796 : * @param input Input text to encrypt/decrypt
797 : * @param input_length Length of ciphertext
798 : * @param key Decryption key
799 : * @param nonce Encryption nonce
800 : * @param nonce_length Length of encryption nonce
801 : * @param output Buffer to write output into
802 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
803 : **/
804 : CHIP_ERROR AES_CTR_crypt(const uint8_t * input, size_t input_length, const Aes128KeyHandle & key, const uint8_t * nonce,
805 : size_t nonce_length, uint8_t * output);
806 :
807 : /**
808 : * @brief Generate a PKCS#10 CSR, usable for Matter, from a P256Keypair.
809 : *
810 : * This uses first principles ASN.1 encoding to avoid relying on the CHIPCryptoPAL backend
811 : * itself, other than to provide an implementation of a P256Keypair * that supports
812 : * at least `::Pubkey()` and `::ECDSA_sign_msg`. This allows using it with
813 : * OS/Platform-bridged private key handling, without requiring a specific
814 : * implementation of other bits like ASN.1.
815 : *
816 : * The CSR will have subject OU set to `CSA`. This is needed since omiting
817 : * subject altogether often trips CSR parsing code. The profile at the CA can
818 : * be configured to ignore CSR requested subject.
819 : *
820 : * @param keypair The key pair for which a CSR should be generated. Must not be null.
821 : * @param csr_span Span to hold the resulting CSR. Must have size at least kMIN_CSR_Buffer_Size.
822 : * Otherwise returns CHIP_ERROR_BUFFER_TOO_SMALL. It will get resized to
823 : * actual size needed on success.
824 :
825 : * @return Returns a CHIP_ERROR from P256Keypair or ASN.1 backend on error, CHIP_NO_ERROR otherwise
826 : **/
827 : CHIP_ERROR GenerateCertificateSigningRequest(const P256Keypair * keypair, MutableByteSpan & csr_span);
828 :
829 : /**
830 : * @brief Common code to validate ASN.1 format/size of a CSR, used by VerifyCertificateSigningRequest.
831 : *
832 : * Ensures it's not obviously malformed and doesn't have trailing garbage.
833 : *
834 : * @param csr CSR in DER format
835 : * @param csr_length The length of the CSR buffer
836 : * @return CHIP_ERROR_UNSUPPORTED_CERT_FORMAT on invalid format, CHIP_NO_ERROR otherwise.
837 : */
838 : CHIP_ERROR VerifyCertificateSigningRequestFormat(const uint8_t * csr, size_t csr_length);
839 :
840 : /**
841 : * @brief Verify the Certificate Signing Request (CSR). If successfully verified, it outputs the public key from the CSR.
842 : *
843 : * The CSR is valid if the format is correct, the signature validates with the embedded public
844 : * key, and there is no trailing garbage data.
845 : *
846 : * @param csr CSR in DER format
847 : * @param csr_length The length of the CSR
848 : * @param pubkey The public key from the verified CSR
849 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
850 : **/
851 : CHIP_ERROR VerifyCertificateSigningRequest(const uint8_t * csr, size_t csr_length, P256PublicKey & pubkey);
852 :
853 : /**
854 : * @brief A function that implements SHA-256 hash
855 : *
856 : * This implements the CHIP_Crypto_Hash() cryptographic primitive
857 : * in the the specification.
858 : *
859 : * @param data The data to hash
860 : * @param data_length Length of the data
861 : * @param out_buffer Pointer to buffer to write output into
862 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
863 : **/
864 :
865 : CHIP_ERROR Hash_SHA256(const uint8_t * data, size_t data_length, uint8_t * out_buffer);
866 :
867 : /**
868 : * @brief A function that implements SHA-1 hash
869 : * @param data The data to hash
870 : * @param data_length Length of the data
871 : * @param out_buffer Pointer to buffer to write output into
872 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
873 : **/
874 :
875 : CHIP_ERROR Hash_SHA1(const uint8_t * data, size_t data_length, uint8_t * out_buffer);
876 :
877 : /**
878 : * @brief A class that defines stream based implementation of SHA-256 hash
879 : * It's expected that the object of this class can be safely copied.
880 : * All implementations must check for std::is_trivially_copyable.
881 : **/
882 :
883 : struct alignas(CHIP_CONFIG_SHA256_CONTEXT_ALIGN) HashSHA256OpaqueContext
884 : {
885 : uint8_t mOpaque[kMAX_Hash_SHA256_Context_Size];
886 : };
887 :
888 : class Hash_SHA256_stream
889 : {
890 : public:
891 : Hash_SHA256_stream();
892 : ~Hash_SHA256_stream();
893 :
894 : /**
895 : * @brief Re-initialize digest computation to an empty context.
896 : *
897 : * @return CHIP_ERROR_INTERNAL on failure to initialize the context,
898 : * CHIP_NO_ERROR otherwise.
899 : */
900 : CHIP_ERROR Begin();
901 :
902 : /**
903 : * @brief Add some data to the digest computation, updating internal state.
904 : *
905 : * @param[in] data The span of bytes to include in the digest update process.
906 : *
907 : * @return CHIP_ERROR_INTERNAL on failure to ingest the data, CHIP_NO_ERROR otherwise.
908 : */
909 : CHIP_ERROR AddData(const ByteSpan data);
910 :
911 : /**
912 : * @brief Get the intermediate padded digest for the current state of the stream.
913 : *
914 : * More data can be added before finish is called.
915 : *
916 : * @param[in,out] out_buffer Output buffer to receive the digest. `out_buffer` must
917 : * be at least `kSHA256_Hash_Length` bytes long. The `out_buffer` size
918 : * will be set to `kSHA256_Hash_Length` on success.
919 : *
920 : * @return CHIP_ERROR_INTERNAL on failure to compute the digest, CHIP_ERROR_BUFFER_TOO_SMALL
921 : * if out_buffer is too small, CHIP_NO_ERROR otherwise.
922 : */
923 : CHIP_ERROR GetDigest(MutableByteSpan & out_buffer);
924 :
925 : /**
926 : * @brief Finalize the stream digest computation, getting the final digest.
927 : *
928 : * @param[in,out] out_buffer Output buffer to receive the digest. `out_buffer` must
929 : * be at least `kSHA256_Hash_Length` bytes long. The `out_buffer` size
930 : * will be set to `kSHA256_Hash_Length` on success.
931 : *
932 : * @return CHIP_ERROR_INTERNAL on failure to compute the digest, CHIP_ERROR_BUFFER_TOO_SMALL
933 : * if out_buffer is too small, CHIP_NO_ERROR otherwise.
934 : */
935 : CHIP_ERROR Finish(MutableByteSpan & out_buffer);
936 :
937 : /**
938 : * @brief Clear-out internal digest data to avoid lingering the state.
939 : */
940 : void Clear();
941 :
942 : private:
943 : HashSHA256OpaqueContext mContext;
944 : };
945 :
946 : class HKDF_sha
947 : {
948 : public:
949 : HKDF_sha() = default;
950 3477 : virtual ~HKDF_sha() = default;
951 :
952 : /**
953 : * @brief A function that implements SHA-256 based HKDF
954 : *
955 : * This implements the CHIP_Crypto_KDF() cryptographic primitive
956 : * in the the specification.
957 : *
958 : * Error values are:
959 : * - CHIP_ERROR_INVALID_ARGUMENT: for any bad arguments or nullptr input on
960 : * any pointer.
961 : * - CHIP_ERROR_INTERNAL: for any unexpected error arising in the underlying
962 : * cryptographic layers.
963 : *
964 : * @param secret The secret to use as the key to the HKDF
965 : * @param secret_length Length of the secret
966 : * @param salt Optional salt to use as input to the HKDF
967 : * @param salt_length Length of the salt
968 : * @param info Optional info to use as input to the HKDF
969 : * @param info_length Length of the info
970 : * @param out_buffer Pointer to buffer to write output into.
971 : * @param out_length Size of the underlying out_buffer. That length of output key material will be generated in out_buffer.
972 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
973 : **/
974 :
975 : virtual CHIP_ERROR HKDF_SHA256(const uint8_t * secret, size_t secret_length, const uint8_t * salt, size_t salt_length,
976 : const uint8_t * info, size_t info_length, uint8_t * out_buffer, size_t out_length);
977 : };
978 :
979 : class HMAC_sha
980 : {
981 : public:
982 : HMAC_sha() = default;
983 98 : virtual ~HMAC_sha() = default;
984 :
985 : /**
986 : * @brief A function that implements SHA-256 based HMAC per FIPS1981.
987 : *
988 : * This implements the CHIP_Crypto_HMAC() cryptographic primitive
989 : * in the the specification.
990 : *
991 : * The `out_length` must be at least kSHA256_Hash_Length, and only
992 : * kSHA256_Hash_Length bytes are written to out_buffer.
993 : *
994 : * Error values are:
995 : * - CHIP_ERROR_INVALID_ARGUMENT: for any bad arguments or nullptr input on
996 : * any pointer.
997 : * - CHIP_ERROR_INTERNAL: for any unexpected error arising in the underlying
998 : * cryptographic layers.
999 : *
1000 : * @param key The key to use for the HMAC operation
1001 : * @param key_length Length of the key
1002 : * @param message Message over which to compute the HMAC
1003 : * @param message_length Length of the message over which to compute the HMAC
1004 : * @param out_buffer Pointer to buffer into which to write the output.
1005 : * @param out_length Underlying size of the `out_buffer`.
1006 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1007 : **/
1008 :
1009 : virtual CHIP_ERROR HMAC_SHA256(const uint8_t * key, size_t key_length, const uint8_t * message, size_t message_length,
1010 : uint8_t * out_buffer, size_t out_length);
1011 :
1012 : /**
1013 : * @brief A function that implements SHA-256 based HMAC per FIPS1981.
1014 : *
1015 : * This implements the CHIP_Crypto_HMAC() cryptographic primitive
1016 : * in the the specification.
1017 : *
1018 : * The `out_length` must be at least kSHA256_Hash_Length, and only
1019 : * kSHA256_Hash_Length bytes are written to out_buffer.
1020 : *
1021 : * Error values are:
1022 : * - CHIP_ERROR_INVALID_ARGUMENT: for any bad arguments or nullptr input on
1023 : * any pointer.
1024 : * - CHIP_ERROR_INTERNAL: for any unexpected error arising in the underlying
1025 : * cryptographic layers.
1026 : *
1027 : * @param key The HMAC Key handle to use for the HMAC operation
1028 : * @param message Message over which to compute the HMAC
1029 : * @param message_length Length of the message over which to compute the HMAC
1030 : * @param out_buffer Pointer to buffer into which to write the output.
1031 : * @param out_length Underlying size of the `out_buffer`.
1032 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1033 : **/
1034 : virtual CHIP_ERROR HMAC_SHA256(const Hmac128KeyHandle & key, const uint8_t * message, size_t message_length,
1035 : uint8_t * out_buffer, size_t out_length);
1036 : };
1037 :
1038 : /**
1039 : * @brief A cryptographically secure random number generator based on NIST SP800-90A
1040 : * @param out_buffer Buffer into which to write random bytes
1041 : * @param out_length Number of random bytes to generate
1042 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1043 : **/
1044 : CHIP_ERROR DRBG_get_bytes(uint8_t * out_buffer, size_t out_length);
1045 :
1046 : /** @brief Entropy callback function
1047 : * @param data Callback-specific data pointer
1048 : * @param output Output data to fill
1049 : * @param len Length of output buffer
1050 : * @param olen The actual amount of data that was written to output buffer
1051 : * @return 0 if success
1052 : */
1053 : typedef int (*entropy_source)(void * data, uint8_t * output, size_t len, size_t * olen);
1054 :
1055 : /** @brief A function to add entropy sources to crypto library
1056 : *
1057 : * This function can be called multiple times to add multiple entropy sources. However,
1058 : * once the entropy source is added, it cannot be removed. Please make sure that the
1059 : * entropy source is valid for the lifetime of the application. Also, make sure that the
1060 : * same entropy source is not added multiple times, e.g.: by calling this function
1061 : * in class constructor or initialization function.
1062 : *
1063 : * @param fn_source Function pointer to the entropy source
1064 : * @param p_source Data that should be provided when fn_source is called
1065 : * @param threshold Minimum required from source before entropy is released
1066 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1067 : **/
1068 : CHIP_ERROR add_entropy_source(entropy_source fn_source, void * p_source, size_t threshold);
1069 :
1070 : class PBKDF2_sha256
1071 : {
1072 : public:
1073 : PBKDF2_sha256() = default;
1074 7 : virtual ~PBKDF2_sha256() = default;
1075 :
1076 : /** @brief Function to derive key using password. SHA256 hashing algorithm is used for calculating hmac.
1077 : * @param password password used for key derivation
1078 : * @param plen length of buffer containing password
1079 : * @param salt salt to use as input to the KDF
1080 : * @param slen length of salt
1081 : * @param iteration_count number of iterations to run
1082 : * @param key_length length of output key
1083 : * @param output output buffer where the key will be written
1084 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1085 : **/
1086 : virtual CHIP_ERROR pbkdf2_sha256(const uint8_t * password, size_t plen, const uint8_t * salt, size_t slen,
1087 : unsigned int iteration_count, uint32_t key_length, uint8_t * output);
1088 : };
1089 :
1090 : // TODO: Extract Spake2p to a separate header and replace the forward declaration with #include SessionKeystore.h
1091 : class SessionKeystore;
1092 :
1093 : /**
1094 : * The below class implements the draft 01 version of the Spake2+ protocol as
1095 : * defined in https://www.ietf.org/id/draft-bar-cfrg-spake2plus-01.html.
1096 : *
1097 : * The following describes the protocol flows:
1098 : *
1099 : * Commissioner Accessory
1100 : * ------------ ---------
1101 : *
1102 : * Init
1103 : * BeginProver
1104 : * ComputeRoundOne ------------->
1105 : * Init
1106 : * BeginVerifier
1107 : * /- ComputeRoundOne
1108 : * <------------- ComputeRoundTwo
1109 : * ComputeRoundTwo ------------->
1110 : * KeyConfirm KeyConfirm
1111 : * GetKeys GetKeys
1112 : *
1113 : **/
1114 : class Spake2p
1115 : {
1116 : public:
1117 : Spake2p(size_t fe_size, size_t point_size, size_t hash_size);
1118 147 : virtual ~Spake2p() = default;
1119 :
1120 : /**
1121 : * @brief Initialize Spake2+ with some context specific information.
1122 : *
1123 : * @param context The context is arbitrary but should include information about the
1124 : * protocol being run, contain the transcript for negotiation, include
1125 : * the PKBDF parameters, etc.
1126 : * @param context_len The length of the context.
1127 : *
1128 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1129 : **/
1130 : virtual CHIP_ERROR Init(const uint8_t * context, size_t context_len);
1131 :
1132 : /**
1133 : * @brief Free Spake2+ underlying objects.
1134 : **/
1135 : virtual void Clear() = 0;
1136 :
1137 : /**
1138 : * @brief Start the Spake2+ process as a verifier (i.e. an accessory being provisioned).
1139 : *
1140 : * @param my_identity The verifier identity. May be NULL if identities are not established.
1141 : * @param my_identity_len The verifier identity length.
1142 : * @param peer_identity The peer identity. May be NULL if identities are not established.
1143 : * @param peer_identity_len The peer identity length.
1144 : * @param w0in The input w0 (a parameter baked into the device or computed with ComputeW0).
1145 : * @param w0in_len The input w0 length.
1146 : * @param Lin The input L (a parameter baked into the device or computed with ComputeL).
1147 : * @param Lin_len The input L length.
1148 : *
1149 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1150 : **/
1151 : virtual CHIP_ERROR BeginVerifier(const uint8_t * my_identity, size_t my_identity_len, const uint8_t * peer_identity,
1152 : size_t peer_identity_len, const uint8_t * w0in, size_t w0in_len, const uint8_t * Lin,
1153 : size_t Lin_len);
1154 :
1155 : /**
1156 : * @brief Start the Spake2+ process as a prover (i.e. a commissioner).
1157 : *
1158 : * @param my_identity The prover identity. May be NULL if identities are not established.
1159 : * @param my_identity_len The prover identity length.
1160 : * @param peer_identity The peer identity. May be NULL if identities are not established.
1161 : * @param peer_identity_len The peer identity length.
1162 : * @param w0in The input w0 (an output from the PBKDF).
1163 : * @param w0in_len The input w0 length.
1164 : * @param w1in The input w1 (an output from the PBKDF).
1165 : * @param w1in_len The input w1 length.
1166 : *
1167 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1168 : **/
1169 : virtual CHIP_ERROR BeginProver(const uint8_t * my_identity, size_t my_identity_len, const uint8_t * peer_identity,
1170 : size_t peer_identity_len, const uint8_t * w0in, size_t w0in_len, const uint8_t * w1in,
1171 : size_t w1in_len);
1172 :
1173 : /**
1174 : * @brief Compute the first round of the protocol.
1175 : *
1176 : * @param pab X value from commissioner.
1177 : * @param pab_len X length.
1178 : * @param out The output first round Spake2+ contribution.
1179 : * @param out_len The output first round Spake2+ contribution length.
1180 : *
1181 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1182 : **/
1183 : virtual CHIP_ERROR ComputeRoundOne(const uint8_t * pab, size_t pab_len, uint8_t * out, size_t * out_len);
1184 :
1185 : /**
1186 : * @brief Compute the second round of the protocol.
1187 : *
1188 : * @param in The peer first round Spake2+ contribution.
1189 : * @param in_len The peer first round Spake2+ contribution length.
1190 : * @param out The output second round Spake2+ contribution.
1191 : * @param out_len The output second round Spake2+ contribution length.
1192 : *
1193 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1194 : **/
1195 : virtual CHIP_ERROR ComputeRoundTwo(const uint8_t * in, size_t in_len, uint8_t * out, size_t * out_len);
1196 :
1197 : /**
1198 : * @brief Confirm that each party computed the same keys.
1199 : *
1200 : * @param in The peer second round Spake2+ contribution.
1201 : * @param in_len The peer second round Spake2+ contribution length.
1202 : *
1203 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1204 : **/
1205 : virtual CHIP_ERROR KeyConfirm(const uint8_t * in, size_t in_len);
1206 :
1207 : /**
1208 : * @brief Return the shared HKDF key.
1209 : *
1210 : * Returns the shared key established during the Spake2+ process, which can be used
1211 : * to derive application-specific keys using HKDF.
1212 : *
1213 : * @param keystore The session keystore for managing the HKDF key lifetime.
1214 : * @param key The output HKDF key.
1215 : *
1216 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1217 : **/
1218 : CHIP_ERROR GetKeys(SessionKeystore & keystore, HkdfKeyHandle & key) const;
1219 :
1220 : CHIP_ERROR InternalHash(const uint8_t * in, size_t in_len);
1221 : CHIP_ERROR WriteMN();
1222 : CHIP_ERROR GenerateKeys();
1223 :
1224 : /**
1225 : * @brief Load a field element.
1226 : *
1227 : * @param in The input big endian field element.
1228 : * @param in_len The size of the input buffer in bytes.
1229 : * @param fe A pointer to an initialized implementation dependant field element.
1230 : *
1231 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1232 : **/
1233 : virtual CHIP_ERROR FELoad(const uint8_t * in, size_t in_len, void * fe) = 0;
1234 :
1235 : /**
1236 : * @brief Write a field element in big-endian format.
1237 : *
1238 : * @param fe The field element to write.
1239 : * @param out The output buffer.
1240 : * @param out_len The length of the output buffer.
1241 : *
1242 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1243 : **/
1244 : virtual CHIP_ERROR FEWrite(const void * fe, uint8_t * out, size_t out_len) = 0;
1245 :
1246 : /**
1247 : * @brief Generate a field element.
1248 : *
1249 : * @param fe A pointer to an initialized implementation dependant field element.
1250 : *
1251 : * @note The implementation must generate a random element from [0, q) where q is the curve order.
1252 : *
1253 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1254 : **/
1255 : virtual CHIP_ERROR FEGenerate(void * fe) = 0;
1256 :
1257 : /**
1258 : * @brief Multiply two field elements, fer = fe1 * fe2.
1259 : *
1260 : * @param fer A pointer to an initialized implementation dependant field element.
1261 : * @param fe1 A pointer to an initialized implementation dependant field element.
1262 : * @param fe2 A pointer to an initialized implementation dependant field element.
1263 : *
1264 : * @note The result must be a field element (i.e. reduced by the curve order).
1265 : *
1266 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1267 : **/
1268 : virtual CHIP_ERROR FEMul(void * fer, const void * fe1, const void * fe2) = 0;
1269 :
1270 : /**
1271 : * @brief Load a point from 0x04 || X || Y format
1272 : *
1273 : * @param in Input buffer
1274 : * @param in_len Input buffer length
1275 : * @param R A pointer to an initialized implementation dependant point.
1276 : *
1277 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1278 : **/
1279 : virtual CHIP_ERROR PointLoad(const uint8_t * in, size_t in_len, void * R) = 0;
1280 :
1281 : /**
1282 : * @brief Write a point in 0x04 || X || Y format
1283 : *
1284 : * @param R A pointer to an initialized implementation dependant point.
1285 : * @param out Output buffer
1286 : * @param out_len Length of the output buffer
1287 : *
1288 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1289 : **/
1290 : virtual CHIP_ERROR PointWrite(const void * R, uint8_t * out, size_t out_len) = 0;
1291 :
1292 : /**
1293 : * @brief Scalar multiplication, R = fe1 * P1.
1294 : *
1295 : * @param R Resultant point
1296 : * @param P1 Input point
1297 : * @param fe1 Input field element.
1298 : *
1299 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1300 : **/
1301 : virtual CHIP_ERROR PointMul(void * R, const void * P1, const void * fe1) = 0;
1302 :
1303 : /**
1304 : * @brief Scalar multiplication with addition, R = fe1 * P1 + fe2 * P2.
1305 : *
1306 : * @param R Resultant point
1307 : * @param P1 Input point
1308 : * @param fe1 Input field element.
1309 : * @param P2 Input point
1310 : * @param fe2 Input field element.
1311 : *
1312 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1313 : **/
1314 : virtual CHIP_ERROR PointAddMul(void * R, const void * P1, const void * fe1, const void * P2, const void * fe2) = 0;
1315 :
1316 : /**
1317 : * @brief Point inversion.
1318 : *
1319 : * @param R Input/Output point to point_invert
1320 : *
1321 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1322 : **/
1323 : virtual CHIP_ERROR PointInvert(void * R) = 0;
1324 :
1325 : /**
1326 : * @brief Multiply a point by the curve cofactor.
1327 : *
1328 : * @param R Input/Output point to point_invert
1329 : *
1330 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1331 : **/
1332 : virtual CHIP_ERROR PointCofactorMul(void * R) = 0;
1333 :
1334 : /*
1335 : * @synopsis Check if a point is on the curve.
1336 : *
1337 : * @param R Input point to check.
1338 : *
1339 : * @return CHIP_NO_ERROR if the point is valid, CHIP_ERROR otherwise.
1340 : */
1341 : virtual CHIP_ERROR PointIsValid(void * R) = 0;
1342 :
1343 : /*
1344 : * @synopsis Compute w0sin mod p
1345 : *
1346 : * @param w0out Output field element (modulo p)
1347 : * @param w0_len Output field element length
1348 : * @param w1sin Input field element
1349 : * @param w1sin_len Input field element length
1350 : *
1351 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1352 : **/
1353 : virtual CHIP_ERROR ComputeW0(uint8_t * w0out, size_t * w0_len, const uint8_t * w0sin, size_t w0sin_len) = 0;
1354 :
1355 : /*
1356 : * @synopsis Compute w1in*G
1357 : *
1358 : * @param Lout Output point in 0x04 || X || Y format.
1359 : * @param L_len Output point length
1360 : * @param w1in Input field element
1361 : * @param w1in_len Input field element size
1362 : *
1363 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1364 : **/
1365 : virtual CHIP_ERROR ComputeL(uint8_t * Lout, size_t * L_len, const uint8_t * w1in, size_t w1in_len) = 0;
1366 :
1367 : void * M;
1368 : void * N;
1369 : const void * G;
1370 : void * X;
1371 : void * Y;
1372 : void * L;
1373 : void * Z;
1374 : void * V;
1375 : void * w0;
1376 : void * w1;
1377 : void * xy;
1378 : void * order;
1379 : void * tempbn;
1380 :
1381 : protected:
1382 : /**
1383 : * @brief Initialize underlying implementation curve, points, field elements, etc.
1384 : *
1385 : * @details The implementation needs to:
1386 : * 1. Initialize each of the points below and set the relevant pointers on the class:
1387 : * a. M
1388 : * b. N
1389 : * c. G
1390 : * d. X
1391 : * e. Y
1392 : * f. L
1393 : * g. Z
1394 : * h. V
1395 : *
1396 : * As an example:
1397 : * this.M = implementation_alloc_point();
1398 : * 2. Initialize each of the field elements below and set the relevant pointers on the class:
1399 : * a. w0
1400 : * b. w1
1401 : * c. xy
1402 : * d. tempbn
1403 : * 3. The hashing context should be initialized
1404 : *
1405 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1406 : **/
1407 : virtual CHIP_ERROR InitImpl() = 0;
1408 :
1409 : /**
1410 : * @brief Hash in_len bytes of in into the internal hash context.
1411 : *
1412 : * @param in The input buffer.
1413 : * @param in_len Size of the input buffer in bytes.
1414 : *
1415 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1416 : **/
1417 : virtual CHIP_ERROR Hash(const uint8_t * in, size_t in_len) = 0;
1418 :
1419 : /**
1420 : * @brief Return the hash.
1421 : *
1422 : * @param out_span Output buffer. The size available must be >= the hash size. It gets resized
1423 : * to hash size on success.
1424 : *
1425 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1426 : **/
1427 : virtual CHIP_ERROR HashFinalize(MutableByteSpan & out_span) = 0;
1428 :
1429 : /**
1430 : * @brief Generate a message authentication code.
1431 : *
1432 : * @param key The MAC key buffer.
1433 : * @param key_len The size of the MAC key in bytes.
1434 : * @param in The input buffer.
1435 : * @param in_len The size of the input data to MAC in bytes.
1436 : * @param out_span The output MAC buffer span. Size must be >= the hash_size. Output size is updated to fit on success.
1437 : *
1438 : * @return Returns a CHIP_ERROR on error, CHIP_NO_ERROR otherwise
1439 : **/
1440 : virtual CHIP_ERROR Mac(const uint8_t * key, size_t key_len, const uint8_t * in, size_t in_len, MutableByteSpan & out_span) = 0;
1441 :
1442 : /**
1443 : * @brief Verify a message authentication code.
1444 : *
1445 : * @param key The MAC key buffer.
1446 : * @param key_len The size of the MAC key in bytes.
1447 : * @param mac The input MAC buffer.
1448 : * @param mac_len The size of the MAC in bytes.
1449 : * @param in The input buffer to verify.
1450 : * @param in_len The size of the input data to verify in bytes.
1451 : *
1452 : * @return Returns a CHIP_ERROR when the MAC doesn't validate, CHIP_NO_ERROR otherwise.
1453 : **/
1454 : virtual CHIP_ERROR MacVerify(const uint8_t * key, size_t key_len, const uint8_t * mac, size_t mac_len, const uint8_t * in,
1455 : size_t in_len) = 0;
1456 :
1457 : /**
1458 : * @brief Derive an key of length out_len.
1459 : *
1460 : * @param ikm The input key material buffer.
1461 : * @param ikm_len The input key material length.
1462 : * @param salt The optional salt. This may be NULL.
1463 : * @param salt_len The size of the salt in bytes.
1464 : * @param info The info.
1465 : * @param info_len The size of the info in bytes.
1466 : * @param out The output key
1467 : * @param out_len The output key length
1468 : *
1469 : * @return Returns a CHIP_ERROR when the MAC doesn't validate, CHIP_NO_ERROR otherwise.
1470 : **/
1471 : virtual CHIP_ERROR KDF(const uint8_t * ikm, size_t ikm_len, const uint8_t * salt, size_t salt_len, const uint8_t * info,
1472 : size_t info_len, uint8_t * out, size_t out_len) = 0;
1473 :
1474 : CHIP_SPAKE2P_ROLE role;
1475 : CHIP_SPAKE2P_STATE state = CHIP_SPAKE2P_STATE::PREINIT;
1476 : size_t fe_size;
1477 : size_t hash_size;
1478 : size_t point_size;
1479 : uint8_t Kcab[kMAX_Hash_Length];
1480 : uint8_t Kae[kMAX_Hash_Length];
1481 : uint8_t * Kca;
1482 : uint8_t * Kcb;
1483 : uint8_t * Ka;
1484 : uint8_t * Ke;
1485 : };
1486 :
1487 : struct alignas(size_t) Spake2pOpaqueContext
1488 : {
1489 : uint8_t mOpaque[kMAX_Spake2p_Context_Size];
1490 : };
1491 :
1492 : class Spake2p_P256_SHA256_HKDF_HMAC : public Spake2p
1493 : {
1494 : public:
1495 1 : Spake2p_P256_SHA256_HKDF_HMAC() : Spake2p(kP256_FE_Length, kP256_Point_Length, kSHA256_Hash_Length)
1496 : {
1497 1 : memset(&mSpake2pContext, 0, sizeof(mSpake2pContext));
1498 1 : }
1499 :
1500 147 : ~Spake2p_P256_SHA256_HKDF_HMAC() override { Spake2p_P256_SHA256_HKDF_HMAC::Clear(); }
1501 :
1502 : void Clear() override;
1503 : CHIP_ERROR Mac(const uint8_t * key, size_t key_len, const uint8_t * in, size_t in_len, MutableByteSpan & out_span) override;
1504 : CHIP_ERROR MacVerify(const uint8_t * key, size_t key_len, const uint8_t * mac, size_t mac_len, const uint8_t * in,
1505 : size_t in_len) override;
1506 : CHIP_ERROR FELoad(const uint8_t * in, size_t in_len, void * fe) override;
1507 : CHIP_ERROR FEWrite(const void * fe, uint8_t * out, size_t out_len) override;
1508 : CHIP_ERROR FEGenerate(void * fe) override;
1509 : CHIP_ERROR FEMul(void * fer, const void * fe1, const void * fe2) override;
1510 :
1511 : CHIP_ERROR PointLoad(const uint8_t * in, size_t in_len, void * R) override;
1512 : CHIP_ERROR PointWrite(const void * R, uint8_t * out, size_t out_len) override;
1513 : CHIP_ERROR PointMul(void * R, const void * P1, const void * fe1) override;
1514 : CHIP_ERROR PointAddMul(void * R, const void * P1, const void * fe1, const void * P2, const void * fe2) override;
1515 : CHIP_ERROR PointInvert(void * R) override;
1516 : CHIP_ERROR PointCofactorMul(void * R) override;
1517 : CHIP_ERROR PointIsValid(void * R) override;
1518 :
1519 : CHIP_ERROR ComputeW0(uint8_t * w0out, size_t * w0_len, const uint8_t * w0sin, size_t w0sin_len) override;
1520 : CHIP_ERROR ComputeL(uint8_t * Lout, size_t * L_len, const uint8_t * w1in, size_t w1in_len) override;
1521 :
1522 : protected:
1523 : CHIP_ERROR InitImpl() override;
1524 : CHIP_ERROR Hash(const uint8_t * in, size_t in_len) override;
1525 : CHIP_ERROR HashFinalize(MutableByteSpan & out_span) override;
1526 : CHIP_ERROR KDF(const uint8_t * secret, size_t secret_length, const uint8_t * salt, size_t salt_length, const uint8_t * info,
1527 : size_t info_length, uint8_t * out, size_t out_length) override;
1528 :
1529 : private:
1530 : CHIP_ERROR InitInternal();
1531 : Hash_SHA256_stream sha256_hash_ctx;
1532 :
1533 : Spake2pOpaqueContext mSpake2pContext;
1534 : };
1535 :
1536 : /**
1537 : * @brief Class used for verifying PASE secure sessions.
1538 : **/
1539 : class Spake2pVerifier
1540 : {
1541 : public:
1542 : uint8_t mW0[kP256_FE_Length];
1543 : uint8_t mL[kP256_Point_Length];
1544 :
1545 : CHIP_ERROR Serialize(MutableByteSpan & outSerialized) const;
1546 : CHIP_ERROR Deserialize(const ByteSpan & inSerialized);
1547 :
1548 : /**
1549 : * @brief Generate the Spake2+ verifier.
1550 : *
1551 : * @param pbkdf2IterCount Iteration count for PBKDF2 function
1552 : * @param salt Salt to be used for Spake2+ operation
1553 : * @param setupPin Provided setup PIN (passcode)
1554 : *
1555 : * @return CHIP_ERROR The result of Spake2+ verifier generation
1556 : */
1557 : CHIP_ERROR Generate(uint32_t pbkdf2IterCount, const ByteSpan & salt, uint32_t setupPin);
1558 :
1559 : /**
1560 : * @brief Compute the initiator values (w0, w1) used for PAKE input.
1561 : *
1562 : * @param pbkdf2IterCount Iteration count for PBKDF2 function
1563 : * @param salt Salt to be used for Spake2+ operation
1564 : * @param setupPin Provided setup PIN (passcode)
1565 : * @param ws The output pair (w0, w1) stored sequentially
1566 : * @param ws_len The output length
1567 : *
1568 : * @return CHIP_ERROR The result from running PBKDF2
1569 : */
1570 : static CHIP_ERROR ComputeWS(uint32_t pbkdf2IterCount, const ByteSpan & salt, uint32_t setupPin, uint8_t * ws, uint32_t ws_len);
1571 : };
1572 :
1573 : /**
1574 : * @brief Serialized format of the Spake2+ Verifier components.
1575 : *
1576 : * This is used when the Verifier should be presented in a serialized form.
1577 : * For example, when it is generated using PBKDF function, when stored in the
1578 : * memory or when sent over the wire.
1579 : * The serialized format is concatentation of 'W0' and 'L' verifier components:
1580 : * { Spake2pVerifier.mW0[kP256_FE_Length], Spake2pVerifier.mL[kP256_Point_Length] }
1581 : **/
1582 : typedef uint8_t Spake2pVerifierSerialized[kSpake2p_VerifierSerialized_Length];
1583 :
1584 : /**
1585 : * @brief Compute the compressed fabric identifier used for operational discovery service
1586 : * records from a Node's root public key and Fabric ID. On success, out_compressed_fabric_id
1587 : * will have a size of exactly kCompressedFabricIdentifierSize.
1588 : *
1589 : * Errors are:
1590 : * - CHIP_ERROR_INVALID_ARGUMENT if root_public_key is invalid
1591 : * - CHIP_ERROR_BUFFER_TOO_SMALL if out_compressed_fabric_id is too small for serialization
1592 : * - CHIP_ERROR_INTERNAL on any unexpected crypto or data conversion errors.
1593 : *
1594 : * @param[in] root_public_key The root public key associated with the node's fabric
1595 : * @param[in] fabric_id The fabric ID associated with the node's fabric
1596 : * @param[out] out_compressed_fabric_id Span where output will be written. Its size must be >= kCompressedFabricIdentifierSize.
1597 : * @returns a CHIP_ERROR (see above) on failure or CHIP_NO_ERROR otherwise.
1598 : */
1599 : CHIP_ERROR GenerateCompressedFabricId(const Crypto::P256PublicKey & root_public_key, uint64_t fabric_id,
1600 : MutableByteSpan & out_compressed_fabric_id);
1601 :
1602 : /**
1603 : * @brief Compute the compressed fabric identifier used for operational discovery service
1604 : * records from a Node's root public key and Fabric ID. This is a conveniance
1605 : * overload that writes to a uint64_t (CompressedFabricId) type.
1606 : *
1607 : * @param[in] rootPublicKey The root public key associated with the node's fabric
1608 : * @param[in] fabricId The fabric ID associated with the node's fabric
1609 : * @param[out] compressedFabricId output location for compressed fabric ID
1610 : * @returns a CHIP_ERROR on failure or CHIP_NO_ERROR otherwise.
1611 : */
1612 : CHIP_ERROR GenerateCompressedFabricId(const Crypto::P256PublicKey & rootPublicKey, uint64_t fabricId,
1613 : uint64_t & compressedFabricId);
1614 :
1615 : enum class CertificateChainValidationResult
1616 : {
1617 : kSuccess = 0,
1618 :
1619 : kRootFormatInvalid = 100,
1620 : kRootArgumentInvalid = 101,
1621 :
1622 : kICAFormatInvalid = 200,
1623 : kICAArgumentInvalid = 201,
1624 :
1625 : kLeafFormatInvalid = 300,
1626 : kLeafArgumentInvalid = 301,
1627 :
1628 : kChainInvalid = 400,
1629 :
1630 : kNoMemory = 500,
1631 :
1632 : kInternalFrameworkError = 600,
1633 : };
1634 :
1635 : CHIP_ERROR ValidateCertificateChain(const uint8_t * rootCertificate, size_t rootCertificateLen, const uint8_t * caCertificate,
1636 : size_t caCertificateLen, const uint8_t * leafCertificate, size_t leafCertificateLen,
1637 : CertificateChainValidationResult & result);
1638 :
1639 : enum class AttestationCertType
1640 : {
1641 : kPAA = 0,
1642 : kPAI = 1,
1643 : kDAC = 2,
1644 : };
1645 :
1646 : CHIP_ERROR VerifyAttestationCertificateFormat(const ByteSpan & cert, AttestationCertType certType);
1647 :
1648 : /**
1649 : * @brief Validate notBefore timestamp of a certificate (candidateCertificate) against validity period of the
1650 : * issuer certificate (issuerCertificate).
1651 : *
1652 : * Errors are:
1653 : * - CHIP_ERROR_CERT_EXPIRED if the candidateCertificate timestamp does not satisfy the issuerCertificate's timestamp.
1654 : * - CHIP_ERROR_INVALID_ARGUMENT when passing an invalid argument.
1655 : * - CHIP_ERROR_INTERNAL on any unexpected crypto or data conversion errors.
1656 : *
1657 : * @param candidateCertificate A DER Certificate ByteSpan those notBefore timestamp to be evaluated.
1658 : * @param issuerCertificate A DER Certificate ByteSpan used to evaluate validity timestamp of the candidateCertificate.
1659 : *
1660 : * @returns a CHIP_ERROR (see above) on failure or CHIP_NO_ERROR otherwise.
1661 : **/
1662 : CHIP_ERROR IsCertificateValidAtIssuance(const ByteSpan & candidateCertificate, const ByteSpan & issuerCertificate);
1663 :
1664 : /**
1665 : * @brief Validate a certificate's validity date against current time.
1666 : *
1667 : * Errors are:
1668 : * - CHIP_ERROR_CERT_EXPIRED if the certificate has expired.
1669 : * - CHIP_ERROR_INVALID_ARGUMENT when passing an invalid argument.
1670 : * - CHIP_ERROR_INTERNAL on any unexpected crypto or data conversion errors.
1671 : *
1672 : * @param certificate A DER Certificate ByteSpan used as the validity reference to be checked against current time.
1673 : *
1674 : * @returns a CHIP_ERROR (see above) on failure or CHIP_NO_ERROR otherwise.
1675 : **/
1676 : CHIP_ERROR IsCertificateValidAtCurrentTime(const ByteSpan & certificate);
1677 :
1678 : CHIP_ERROR ExtractPubkeyFromX509Cert(const ByteSpan & certificate, Crypto::P256PublicKey & pubkey);
1679 :
1680 : /**
1681 : * @brief Extracts the Subject Key Identifier from an X509 Certificate.
1682 : **/
1683 : CHIP_ERROR ExtractSKIDFromX509Cert(const ByteSpan & certificate, MutableByteSpan & skid);
1684 :
1685 : /**
1686 : * @brief Extracts the Authority Key Identifier from an X509 Certificate.
1687 : **/
1688 : CHIP_ERROR ExtractAKIDFromX509Cert(const ByteSpan & certificate, MutableByteSpan & akid);
1689 :
1690 : /**
1691 : * @brief Extracts the CRL Distribution Point (CDP) extension from an X509 ASN.1 Encoded Certificate.
1692 : * The returned value only covers the URI of the CDP. Only a single URI distribution point
1693 : * GeneralName is supported, and only those that start with "http://" and "https://".
1694 : *
1695 : * @returns CHIP_ERROR_NOT_FOUND if not found or wrong format.
1696 : * CHIP_NO_ERROR otherwise.
1697 : **/
1698 : CHIP_ERROR ExtractCRLDistributionPointURIFromX509Cert(const ByteSpan & certificate, MutableCharSpan & cdpurl);
1699 :
1700 : /**
1701 : * @brief Extracts the CRL Distribution Point (CDP) extension's cRLIssuer Name from an X509 ASN.1 Encoded Certificate.
1702 : * The value is copied into buffer in a raw ASN.1 X.509 format. This format should be directly comparable
1703 : * with the result of ExtractSubjectFromX509Cert().
1704 : *
1705 : * @returns CHIP_ERROR_NOT_FOUND if not found or wrong format.
1706 : * CHIP_NO_ERROR otherwise.
1707 : **/
1708 : CHIP_ERROR ExtractCDPExtensionCRLIssuerFromX509Cert(const ByteSpan & certificate, MutableByteSpan & crlIssuer);
1709 :
1710 : /**
1711 : * @brief Extracts Serial Number from X509 Certificate.
1712 : **/
1713 : CHIP_ERROR ExtractSerialNumberFromX509Cert(const ByteSpan & certificate, MutableByteSpan & serialNumber);
1714 :
1715 : /**
1716 : * @brief Extracts Subject Distinguished Name from X509 Certificate. The value is copied into buffer in a raw ASN.1 X.509 format.
1717 : **/
1718 : CHIP_ERROR ExtractSubjectFromX509Cert(const ByteSpan & certificate, MutableByteSpan & subject);
1719 :
1720 : /**
1721 : * @brief Extracts Issuer Distinguished Name from X509 Certificate. The value is copied into buffer in a raw ASN.1 X.509 format.
1722 : **/
1723 : CHIP_ERROR ExtractIssuerFromX509Cert(const ByteSpan & certificate, MutableByteSpan & issuer);
1724 :
1725 : /**
1726 : * @brief Checks for resigned version of the certificate in the list and returns it.
1727 : *
1728 : * The following conditions SHOULD be satisfied for the certificate to qualify as
1729 : * a resigned version of a reference certificate:
1730 : * - SKID of the candidate and the reference certificate should match.
1731 : * - SubjectDN of the candidate and the reference certificate should match.
1732 : *
1733 : * If no resigned version is found then reference certificate itself is returned.
1734 : *
1735 : * @param referenceCertificate A DER certificate.
1736 : * @param candidateCertificates A pointer to the list of DER Certificates, which should be searched
1737 : * for the resigned version of `referenceCertificate`.
1738 : * @param candidateCertificatesCount Number of certificates in the `candidateCertificates` list.
1739 : * @param outCertificate A reference to the certificate or it's resigned version if found.
1740 : * Note that it points to either `referenceCertificate` or one of
1741 : * `candidateCertificates`, but it doesn't copy data.
1742 : *
1743 : * @returns error if there is certificate parsing/format issue or CHIP_NO_ERROR otherwise.
1744 : **/
1745 : CHIP_ERROR ReplaceCertIfResignedCertFound(const ByteSpan & referenceCertificate, const ByteSpan * candidateCertificates,
1746 : size_t candidateCertificatesCount, ByteSpan & outCertificate);
1747 :
1748 : /**
1749 : * Defines DN attribute types that can include endocing of VID/PID parameters.
1750 : */
1751 : enum class DNAttrType
1752 : {
1753 : kUnspecified = 0,
1754 : kCommonName = 1,
1755 : kMatterVID = 2,
1756 : kMatterPID = 3,
1757 : };
1758 :
1759 : /**
1760 : * @struct AttestationCertVidPid
1761 : *
1762 : * @brief
1763 : * A data structure representing Attestation Certificate VID and PID attributes.
1764 : */
1765 : struct AttestationCertVidPid
1766 : {
1767 : Optional<VendorId> mVendorId;
1768 : Optional<uint16_t> mProductId;
1769 :
1770 659 : bool Initialized() const { return (mVendorId.HasValue() || mProductId.HasValue()); }
1771 : };
1772 :
1773 : /**
1774 : * @brief Extracts VID and PID attributes from the DN Attribute string.
1775 : * If attribute is not present the corresponding output value stays uninitialized.
1776 : *
1777 : * @return CHIP_ERROR_INVALID_ARGUMENT if wrong input is provided.
1778 : * CHIP_ERROR_WRONG_CERT_DN if encoding of kMatterVID and kMatterPID attributes is wrong.
1779 : * CHIP_NO_ERROR otherwise.
1780 : **/
1781 : CHIP_ERROR ExtractVIDPIDFromAttributeString(DNAttrType attrType, const ByteSpan & attr,
1782 : AttestationCertVidPid & vidpidFromMatterAttr, AttestationCertVidPid & vidpidFromCNAttr);
1783 :
1784 : /**
1785 : * @brief Extracts VID and PID attributes from the Subject DN of an X509 Certificate.
1786 : * If attribute is not present the corresponding output value stays uninitialized.
1787 : **/
1788 : CHIP_ERROR ExtractVIDPIDFromX509Cert(const ByteSpan & x509Cert, AttestationCertVidPid & vidpid);
1789 :
1790 : /**
1791 : * @brief The set of credentials needed to operate group message security with symmetric keys.
1792 : */
1793 : typedef struct GroupOperationalCredentials
1794 : {
1795 : /// Validity start time in microseconds since 2000-01-01T00:00:00 UTC ("the Epoch")
1796 : uint64_t start_time;
1797 : /// Session Id
1798 : uint16_t hash;
1799 : /// Operational group key
1800 : uint8_t encryption_key[Crypto::CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES];
1801 : /// Privacy key
1802 : uint8_t privacy_key[Crypto::CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES];
1803 : } GroupOperationalCredentials;
1804 :
1805 : /**
1806 : * @brief Opaque context used to protect a symmetric key. The key operations must
1807 : * be performed without exposing the protected key value.
1808 : */
1809 : class SymmetricKeyContext
1810 : {
1811 : public:
1812 : /**
1813 : * @brief Returns the symmetric key hash
1814 : *
1815 : * TODO: Replace GetKeyHash() with DeriveGroupSessionId(SymmetricKeyContext &, uint16_t & session_id)
1816 : *
1817 : * @return Group Key Hash
1818 : */
1819 : virtual uint16_t GetKeyHash() = 0;
1820 :
1821 9 : virtual ~SymmetricKeyContext() = default;
1822 : /**
1823 : * @brief Perform the message encryption as described in 4.7.2. (Security Processing of Outgoing Messages)
1824 : * @param[in] plaintext Outgoing message payload.
1825 : * @param[in] aad Additional data (message header contents)
1826 : * @param[in] nonce Nonce (Security Flags | Message Counter | Source Node ID)
1827 : * @param[out] mic Outgoing Message Integrity Check
1828 : * @param[out] ciphertext Outgoing encrypted payload. Must be at least as big as plaintext. The same buffer may be used both
1829 : * for ciphertext, and plaintext.
1830 : * @return CHIP_ERROR
1831 : */
1832 : virtual CHIP_ERROR MessageEncrypt(const ByteSpan & plaintext, const ByteSpan & aad, const ByteSpan & nonce,
1833 : MutableByteSpan & mic, MutableByteSpan & ciphertext) const = 0;
1834 : /**
1835 : * @brief Perform the message decryption as described in 4.7.3.(Security Processing of Incoming Messages)
1836 : * @param[in] ciphertext Incoming encrypted payload
1837 : * @param[in] aad Additional data (message header contents)
1838 : * @param[in] nonce Nonce (Security Flags | Message Counter | Source Node ID)
1839 : * @param[in] mic Incoming Message Integrity Check
1840 : * @param[out] plaintext Incoming message payload. Must be at least as big as ciphertext. The same buffer may be used both
1841 : * for plaintext, and ciphertext.
1842 : * @return CHIP_ERROR
1843 : */
1844 : virtual CHIP_ERROR MessageDecrypt(const ByteSpan & ciphertext, const ByteSpan & aad, const ByteSpan & nonce,
1845 : const ByteSpan & mic, MutableByteSpan & plaintext) const = 0;
1846 :
1847 : /**
1848 : * @brief Perform privacy encoding as described in 4.8.2. (Privacy Processing of Outgoing Messages)
1849 : * @param[in] input Message header to privacy encrypt
1850 : * @param[in] nonce Privacy Nonce = session_id | mic
1851 : * @param[out] output Message header obfuscated
1852 : * @return CHIP_ERROR
1853 : */
1854 : virtual CHIP_ERROR PrivacyEncrypt(const ByteSpan & input, const ByteSpan & nonce, MutableByteSpan & output) const = 0;
1855 :
1856 : /**
1857 : * @brief Perform privacy decoding as described in 4.8.3. (Privacy Processing of Incoming Messages)
1858 : * @param[in] input Message header to privacy decrypt
1859 : * @param[in] nonce Privacy Nonce = session_id | mic
1860 : * @param[out] output Message header deobfuscated
1861 : * @return CHIP_ERROR
1862 : */
1863 : virtual CHIP_ERROR PrivacyDecrypt(const ByteSpan & input, const ByteSpan & nonce, MutableByteSpan & output) const = 0;
1864 :
1865 : /**
1866 : * @brief Release resources such as dynamic memory used to allocate this instance of the SymmetricKeyContext
1867 : */
1868 : virtual void Release() = 0;
1869 : };
1870 :
1871 : /**
1872 : * @brief Derives the Operational Group Key using the Key Derivation Function (KDF) from the given epoch key.
1873 : * @param[in] epoch_key The epoch key. Must be CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES bytes length.
1874 : * @param[in] compressed_fabric_id The compressed fabric ID for the fabric (big endian byte string)
1875 : * @param[out] out_key Symmetric key used as the encryption key during message processing for group communication.
1876 : The buffer size must be at least CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES bytes length.
1877 : * @return Returns a CHIP_NO_ERROR on succcess, or CHIP_ERROR_INTERNAL if the provided key is invalid.
1878 : **/
1879 : CHIP_ERROR DeriveGroupOperationalKey(const ByteSpan & epoch_key, const ByteSpan & compressed_fabric_id, MutableByteSpan & out_key);
1880 :
1881 : /**
1882 : * @brief Derives the Group Session ID from a given operational group key using
1883 : * the Key Derivation Function (Group Key Hash)
1884 : * @param[in] operational_key The operational group key. Must be CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES bytes length.
1885 : * @param[out] session_id Output of the Group Key Hash
1886 : * @return Returns a CHIP_NO_ERROR on succcess, or CHIP_ERROR_INVALID_ARGUMENT if the provided key is invalid.
1887 : **/
1888 : CHIP_ERROR DeriveGroupSessionId(const ByteSpan & operational_key, uint16_t & session_id);
1889 :
1890 : /**
1891 : * @brief Derives the Privacy Group Key using the Key Derivation Function (KDF) from the given epoch key.
1892 : * @param[in] epoch_key The epoch key. Must be CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES bytes length.
1893 : * @param[out] out_key Symmetric key used as the privacy key during message processing for group communication.
1894 : * The buffer size must be at least CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES bytes length.
1895 : * @return Returns a CHIP_NO_ERROR on succcess, or CHIP_ERROR_INTERNAL if the provided key is invalid.
1896 : **/
1897 : CHIP_ERROR DeriveGroupPrivacyKey(const ByteSpan & epoch_key, MutableByteSpan & out_key);
1898 :
1899 : /**
1900 : * @brief Derives the complete set of credentials needed for group security.
1901 : *
1902 : * This function will derive the Encryption Key, Group Key Hash (Session Id), and Privacy Key
1903 : * for the given Epoch Key and Compressed Fabric Id.
1904 : * @param[in] epoch_key The epoch key. Must be CHIP_CRYPTO_SYMMETRIC_KEY_LENGTH_BYTES bytes length.
1905 : * @param[in] compressed_fabric_id The compressed fabric ID for the fabric (big endian byte string)
1906 : * @param[out] operational_credentials The set of Symmetric keys used during message processing for group communication.
1907 : * @return Returns a CHIP_NO_ERROR on succcess, or CHIP_ERROR_INTERNAL if the provided key is invalid.
1908 : **/
1909 : CHIP_ERROR DeriveGroupOperationalCredentials(const ByteSpan & epoch_key, const ByteSpan & compressed_fabric_id,
1910 : GroupOperationalCredentials & operational_credentials);
1911 : } // namespace Crypto
1912 : } // namespace chip
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