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pigweed / third_party / github / project-chip / connectedhomeip / 918d3ad7b1f341e4a62f5255539c029be633359f / . / src / crypto / CHIPCryptoPALmbedTLS.cpp
blob: 2ce3bc7aba8c3096a28a0859662d362b2efc2b51 [file] [log] [blame]
/*
*
* Copyright (c) 2020-2022 Project CHIP Authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* @file
* mbedTLS based implementation of CHIP crypto primitives
*/
#include "CHIPCryptoPAL.h"
#include <type_traits>
#include <mbedtls/bignum.h>
#include <mbedtls/ccm.h>
#include <mbedtls/ctr_drbg.h>
#include <mbedtls/ecdh.h>
#include <mbedtls/ecdsa.h>
#include <mbedtls/ecp.h>
#include <mbedtls/entropy.h>
#include <mbedtls/error.h>
#include <mbedtls/hkdf.h>
#include <mbedtls/md.h>
#include <mbedtls/pkcs5.h>
#include <mbedtls/sha1.h>
#include <mbedtls/sha256.h>
#if defined(MBEDTLS_X509_CRT_PARSE_C)
#include <mbedtls/x509_crt.h>
#endif // defined(MBEDTLS_X509_CRT_PARSE_C)
#include <mbedtls/oid.h>
#include <mbedtls/x509.h>
#include <mbedtls/x509_csr.h>
#include <lib/core/CHIPSafeCasts.h>
#include <lib/support/BufferWriter.h>
#include <lib/support/BytesToHex.h>
#include <lib/support/CHIPArgParser.hpp>
#include <lib/support/CodeUtils.h>
#include <lib/support/SafeInt.h>
#include <lib/support/SafePointerCast.h>
#include <lib/support/logging/CHIPLogging.h>
#include <string.h>
namespace chip {
namespace Crypto {
#define MAX_ERROR_STR_LEN 128
#define NUM_BYTES_IN_SHA256_HASH 32
// In mbedTLS 3.0.0 direct access to structure fields was replaced with using MBEDTLS_PRIVATE macro.
#if (MBEDTLS_VERSION_NUMBER >= 0x03000000)
#define CHIP_CRYPTO_PAL_PRIVATE(x) MBEDTLS_PRIVATE(x)
#else
#define CHIP_CRYPTO_PAL_PRIVATE(x) x
#endif
#if (MBEDTLS_VERSION_NUMBER >= 0x03000000 && MBEDTLS_VERSION_NUMBER < 0x03010000)
#define CHIP_CRYPTO_PAL_PRIVATE_X509(x) MBEDTLS_PRIVATE(x)
#else
#define CHIP_CRYPTO_PAL_PRIVATE_X509(x) x
#endif
typedef struct
{
bool mInitialized;
bool mDRBGSeeded;
mbedtls_ctr_drbg_context mDRBGCtxt;
mbedtls_entropy_context mEntropy;
} EntropyContext;
static EntropyContext gsEntropyContext;
static void _log_mbedTLS_error(int error_code)
{
if (error_code != 0)
{
#if defined(MBEDTLS_ERROR_C)
char error_str[MAX_ERROR_STR_LEN];
mbedtls_strerror(error_code, error_str, sizeof(error_str));
ChipLogError(Crypto, "mbedTLS error: %s", error_str);
#else
// Error codes defined in 16-bit negative hex numbers. Ease lookup by printing likewise
ChipLogError(Crypto, "mbedTLS error: -0x%04X", -static_cast<uint16_t>(error_code));
#endif
}
}
static bool _isValidTagLength(size_t tag_length)
{
if (tag_length == 8 || tag_length == 12 || tag_length == 16)
{
return true;
}
return false;
}
static bool _isValidKeyLength(size_t length)
{
// 16 bytes key for AES-CCM-128, 32 for AES-CCM-256
if (length == 16 || length == 32)
{
return true;
}
return false;
}
CHIP_ERROR AES_CCM_encrypt(const uint8_t * plaintext, size_t plaintext_length, const uint8_t * aad, size_t aad_length,
const uint8_t * key, size_t key_length, const uint8_t * nonce, size_t nonce_length, uint8_t * ciphertext,
uint8_t * tag, size_t tag_length)
{
CHIP_ERROR error = CHIP_NO_ERROR;
int result = 1;
mbedtls_ccm_context context;
mbedtls_ccm_init(&context);
VerifyOrExit(plaintext != nullptr || plaintext_length == 0, error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(ciphertext != nullptr || plaintext_length == 0, error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(key != nullptr, error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(_isValidKeyLength(key_length), error = CHIP_ERROR_UNSUPPORTED_ENCRYPTION_TYPE);
VerifyOrExit(nonce != nullptr, error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(nonce_length > 0, error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(tag != nullptr, error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(_isValidTagLength(tag_length), error = CHIP_ERROR_INVALID_ARGUMENT);
if (aad_length > 0)
{
VerifyOrExit(aad != nullptr, error = CHIP_ERROR_INVALID_ARGUMENT);
}
// Size of key = key_length * number of bits in a byte (8)
// Cast is safe because we called _isValidKeyLength above.
result =
mbedtls_ccm_setkey(&context, MBEDTLS_CIPHER_ID_AES, Uint8::to_const_uchar(key), static_cast<unsigned int>(key_length * 8));
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
// Encrypt
result = mbedtls_ccm_encrypt_and_tag(&context, plaintext_length, Uint8::to_const_uchar(nonce), nonce_length,
Uint8::to_const_uchar(aad), aad_length, Uint8::to_const_uchar(plaintext),
Uint8::to_uchar(ciphertext), Uint8::to_uchar(tag), tag_length);
_log_mbedTLS_error(result);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
exit:
mbedtls_ccm_free(&context);
return error;
}
CHIP_ERROR AES_CCM_decrypt(const uint8_t * ciphertext, size_t ciphertext_len, const uint8_t * aad, size_t aad_len,
const uint8_t * tag, size_t tag_length, const uint8_t * key, size_t key_length, const uint8_t * nonce,
size_t nonce_length, uint8_t * plaintext)
{
CHIP_ERROR error = CHIP_NO_ERROR;
int result = 1;
mbedtls_ccm_context context;
mbedtls_ccm_init(&context);
VerifyOrExit(plaintext != nullptr || ciphertext_len == 0, error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(ciphertext != nullptr || ciphertext_len == 0, error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(tag != nullptr, error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(_isValidTagLength(tag_length), error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(key != nullptr, error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(_isValidKeyLength(key_length), error = CHIP_ERROR_UNSUPPORTED_ENCRYPTION_TYPE);
VerifyOrExit(nonce != nullptr, error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(nonce_length > 0, error = CHIP_ERROR_INVALID_ARGUMENT);
if (aad_len > 0)
{
VerifyOrExit(aad != nullptr, error = CHIP_ERROR_INVALID_ARGUMENT);
}
// Size of key = key_length * number of bits in a byte (8)
// Cast is safe because we called _isValidKeyLength above.
result =
mbedtls_ccm_setkey(&context, MBEDTLS_CIPHER_ID_AES, Uint8::to_const_uchar(key), static_cast<unsigned int>(key_length * 8));
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
// Decrypt
result = mbedtls_ccm_auth_decrypt(&context, ciphertext_len, Uint8::to_const_uchar(nonce), nonce_length,
Uint8::to_const_uchar(aad), aad_len, Uint8::to_const_uchar(ciphertext),
Uint8::to_uchar(plaintext), Uint8::to_const_uchar(tag), tag_length);
_log_mbedTLS_error(result);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
exit:
mbedtls_ccm_free(&context);
return error;
}
CHIP_ERROR Hash_SHA256(const uint8_t * data, const size_t data_length, uint8_t * out_buffer)
{
// zero data length hash is supported.
VerifyOrReturnError(data != nullptr, CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrReturnError(out_buffer != nullptr, CHIP_ERROR_INVALID_ARGUMENT);
#if (MBEDTLS_VERSION_NUMBER >= 0x03000000)
const int result = mbedtls_sha256(Uint8::to_const_uchar(data), data_length, Uint8::to_uchar(out_buffer), 0);
#else
const int result = mbedtls_sha256_ret(Uint8::to_const_uchar(data), data_length, Uint8::to_uchar(out_buffer), 0);
#endif
VerifyOrReturnError(result == 0, CHIP_ERROR_INTERNAL);
return CHIP_NO_ERROR;
}
CHIP_ERROR Hash_SHA1(const uint8_t * data, const size_t data_length, uint8_t * out_buffer)
{
// zero data length hash is supported.
VerifyOrReturnError(out_buffer != nullptr, CHIP_ERROR_INVALID_ARGUMENT);
#if (MBEDTLS_VERSION_NUMBER >= 0x03000000)
const int result = mbedtls_sha1(Uint8::to_const_uchar(data), data_length, Uint8::to_uchar(out_buffer));
#else
const int result = mbedtls_sha1_ret(Uint8::to_const_uchar(data), data_length, Uint8::to_uchar(out_buffer));
#endif
VerifyOrReturnError(result == 0, CHIP_ERROR_INTERNAL);
return CHIP_NO_ERROR;
}
static_assert(kMAX_Hash_SHA256_Context_Size >= sizeof(mbedtls_sha256_context),
"kMAX_Hash_SHA256_Context_Size is too small for the size of underlying mbedtls_sha256_context");
static inline mbedtls_sha256_context * to_inner_hash_sha256_context(HashSHA256OpaqueContext * context)
{
return SafePointerCast<mbedtls_sha256_context *>(context);
}
Hash_SHA256_stream::Hash_SHA256_stream()
{
mbedtls_sha256_context * context = to_inner_hash_sha256_context(&mContext);
mbedtls_sha256_init(context);
}
Hash_SHA256_stream::~Hash_SHA256_stream()
{
mbedtls_sha256_context * context = to_inner_hash_sha256_context(&mContext);
mbedtls_sha256_free(context);
Clear();
}
CHIP_ERROR Hash_SHA256_stream::Begin()
{
mbedtls_sha256_context * const context = to_inner_hash_sha256_context(&mContext);
#if (MBEDTLS_VERSION_NUMBER >= 0x03000000)
const int result = mbedtls_sha256_starts(context, 0);
#else
const int result = mbedtls_sha256_starts_ret(context, 0);
#endif
VerifyOrReturnError(result == 0, CHIP_ERROR_INTERNAL);
return CHIP_NO_ERROR;
}
CHIP_ERROR Hash_SHA256_stream::AddData(const ByteSpan data)
{
mbedtls_sha256_context * const context = to_inner_hash_sha256_context(&mContext);
#if (MBEDTLS_VERSION_NUMBER >= 0x03000000)
const int result = mbedtls_sha256_update(context, Uint8::to_const_uchar(data.data()), data.size());
#else
const int result = mbedtls_sha256_update_ret(context, Uint8::to_const_uchar(data.data()), data.size());
#endif
VerifyOrReturnError(result == 0, CHIP_ERROR_INTERNAL);
return CHIP_NO_ERROR;
}
CHIP_ERROR Hash_SHA256_stream::GetDigest(MutableByteSpan & out_buffer)
{
mbedtls_sha256_context * context = to_inner_hash_sha256_context(&mContext);
// Back-up context as we are about to finalize the hash to extract digest.
mbedtls_sha256_context previous_ctx;
mbedtls_sha256_init(&previous_ctx);
mbedtls_sha256_clone(&previous_ctx, context);
// Pad + compute digest, then finalize context. It is restored next line to continue.
CHIP_ERROR result = Finish(out_buffer);
// Restore context prior to finalization.
mbedtls_sha256_clone(context, &previous_ctx);
mbedtls_sha256_free(&previous_ctx);
return result;
}
CHIP_ERROR Hash_SHA256_stream::Finish(MutableByteSpan & out_buffer)
{
VerifyOrReturnError(out_buffer.size() >= kSHA256_Hash_Length, CHIP_ERROR_BUFFER_TOO_SMALL);
mbedtls_sha256_context * const context = to_inner_hash_sha256_context(&mContext);
#if (MBEDTLS_VERSION_NUMBER >= 0x03000000)
const int result = mbedtls_sha256_finish(context, Uint8::to_uchar(out_buffer.data()));
#else
const int result = mbedtls_sha256_finish_ret(context, Uint8::to_uchar(out_buffer.data()));
#endif
VerifyOrReturnError(result == 0, CHIP_ERROR_INTERNAL);
out_buffer = out_buffer.SubSpan(0, kSHA256_Hash_Length);
return CHIP_NO_ERROR;
}
void Hash_SHA256_stream::Clear()
{
mbedtls_platform_zeroize(this, sizeof(*this));
}
CHIP_ERROR HKDF_sha::HKDF_SHA256(const uint8_t * secret, const size_t secret_length, const uint8_t * salt, const size_t salt_length,
const uint8_t * info, const size_t info_length, uint8_t * out_buffer, size_t out_length)
{
VerifyOrReturnError(secret != nullptr, CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrReturnError(secret_length > 0, CHIP_ERROR_INVALID_ARGUMENT);
// Salt is optional
if (salt_length > 0)
{
VerifyOrReturnError(salt != nullptr, CHIP_ERROR_INVALID_ARGUMENT);
}
VerifyOrReturnError(info_length > 0, CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrReturnError(info != nullptr, CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrReturnError(out_length > 0, CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrReturnError(out_buffer != nullptr, CHIP_ERROR_INVALID_ARGUMENT);
const mbedtls_md_info_t * const md = mbedtls_md_info_from_type(MBEDTLS_MD_SHA256);
VerifyOrReturnError(md != nullptr, CHIP_ERROR_INTERNAL);
const int result = mbedtls_hkdf(md, Uint8::to_const_uchar(salt), salt_length, Uint8::to_const_uchar(secret), secret_length,
Uint8::to_const_uchar(info), info_length, Uint8::to_uchar(out_buffer), out_length);
_log_mbedTLS_error(result);
VerifyOrReturnError(result == 0, CHIP_ERROR_INTERNAL);
return CHIP_NO_ERROR;
}
CHIP_ERROR HMAC_sha::HMAC_SHA256(const uint8_t * key, size_t key_length, const uint8_t * message, size_t message_length,
uint8_t * out_buffer, size_t out_length)
{
VerifyOrReturnError(key != nullptr, CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrReturnError(key_length > 0, CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrReturnError(message != nullptr, CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrReturnError(message_length > 0, CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrReturnError(out_length >= kSHA256_Hash_Length, CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrReturnError(out_buffer != nullptr, CHIP_ERROR_INVALID_ARGUMENT);
const mbedtls_md_info_t * const md = mbedtls_md_info_from_type(MBEDTLS_MD_SHA256);
VerifyOrReturnError(md != nullptr, CHIP_ERROR_INTERNAL);
const int result =
mbedtls_md_hmac(md, Uint8::to_const_uchar(key), key_length, Uint8::to_const_uchar(message), message_length, out_buffer);
_log_mbedTLS_error(result);
VerifyOrReturnError(result == 0, CHIP_ERROR_INTERNAL);
return CHIP_NO_ERROR;
}
CHIP_ERROR PBKDF2_sha256::pbkdf2_sha256(const uint8_t * password, size_t plen, const uint8_t * salt, size_t slen,
unsigned int iteration_count, uint32_t key_length, uint8_t * output)
{
CHIP_ERROR error = CHIP_NO_ERROR;
int result = 0;
const mbedtls_md_info_t * md_info;
mbedtls_md_context_t md_ctxt;
constexpr int use_hmac = 1;
bool free_md_ctxt = false;
VerifyOrExit(password != nullptr, error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(plen > 0, error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(salt != nullptr, error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(slen >= kSpake2p_Min_PBKDF_Salt_Length, error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(slen <= kSpake2p_Max_PBKDF_Salt_Length, error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(key_length > 0, error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(output != nullptr, error = CHIP_ERROR_INVALID_ARGUMENT);
md_info = mbedtls_md_info_from_type(MBEDTLS_MD_SHA256);
VerifyOrExit(md_info != nullptr, error = CHIP_ERROR_INTERNAL);
mbedtls_md_init(&md_ctxt);
free_md_ctxt = true;
result = mbedtls_md_setup(&md_ctxt, md_info, use_hmac);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
result = mbedtls_pkcs5_pbkdf2_hmac(&md_ctxt, Uint8::to_const_uchar(password), plen, Uint8::to_const_uchar(salt), slen,
iteration_count, key_length, Uint8::to_uchar(output));
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
exit:
_log_mbedTLS_error(result);
if (free_md_ctxt)
{
mbedtls_md_free(&md_ctxt);
}
return error;
}
static EntropyContext * get_entropy_context()
{
if (!gsEntropyContext.mInitialized)
{
mbedtls_entropy_init(&gsEntropyContext.mEntropy);
mbedtls_ctr_drbg_init(&gsEntropyContext.mDRBGCtxt);
gsEntropyContext.mInitialized = true;
}
return &gsEntropyContext;
}
static mbedtls_ctr_drbg_context * get_drbg_context()
{
EntropyContext * const context = get_entropy_context();
mbedtls_ctr_drbg_context * const drbgCtxt = &context->mDRBGCtxt;
if (!context->mDRBGSeeded)
{
const int status = mbedtls_ctr_drbg_seed(drbgCtxt, mbedtls_entropy_func, &context->mEntropy, nullptr, 0);
if (status != 0)
{
_log_mbedTLS_error(status);
return nullptr;
}
context->mDRBGSeeded = true;
}
return drbgCtxt;
}
CHIP_ERROR add_entropy_source(entropy_source fn_source, void * p_source, size_t threshold)
{
VerifyOrReturnError(fn_source != nullptr, CHIP_ERROR_INVALID_ARGUMENT);
EntropyContext * const entropy_ctxt = get_entropy_context();
VerifyOrReturnError(entropy_ctxt != nullptr, CHIP_ERROR_INTERNAL);
const int result =
mbedtls_entropy_add_source(&entropy_ctxt->mEntropy, fn_source, p_source, threshold, MBEDTLS_ENTROPY_SOURCE_STRONG);
VerifyOrReturnError(result == 0, CHIP_ERROR_INTERNAL);
return CHIP_NO_ERROR;
}
CHIP_ERROR DRBG_get_bytes(uint8_t * out_buffer, const size_t out_length)
{
VerifyOrReturnError(out_buffer != nullptr, CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrReturnError(out_length > 0, CHIP_ERROR_INVALID_ARGUMENT);
mbedtls_ctr_drbg_context * const drbg_ctxt = get_drbg_context();
VerifyOrReturnError(drbg_ctxt != nullptr, CHIP_ERROR_INTERNAL);
const int result = mbedtls_ctr_drbg_random(drbg_ctxt, Uint8::to_uchar(out_buffer), out_length);
VerifyOrReturnError(result == 0, CHIP_ERROR_INTERNAL);
return CHIP_NO_ERROR;
}
static int CryptoRNG(void * ctxt, uint8_t * out_buffer, size_t out_length)
{
return (chip::Crypto::DRBG_get_bytes(out_buffer, out_length) == CHIP_NO_ERROR) ? 0 : 1;
}
mbedtls_ecp_group_id MapECPGroupId(SupportedECPKeyTypes keyType)
{
switch (keyType)
{
case SupportedECPKeyTypes::ECP256R1:
return MBEDTLS_ECP_DP_SECP256R1;
default:
return MBEDTLS_ECP_DP_NONE;
}
}
static inline mbedtls_ecp_keypair * to_keypair(P256KeypairContext * context)
{
return SafePointerCast<mbedtls_ecp_keypair *>(context);
}
static inline const mbedtls_ecp_keypair * to_const_keypair(const P256KeypairContext * context)
{
return SafePointerCast<const mbedtls_ecp_keypair *>(context);
}
CHIP_ERROR P256Keypair::ECDSA_sign_msg(const uint8_t * msg, const size_t msg_length, P256ECDSASignature & out_signature) const
{
VerifyOrReturnError(mInitialized, CHIP_ERROR_WELL_UNINITIALIZED);
VerifyOrReturnError((msg != nullptr) && (msg_length > 0), CHIP_ERROR_INVALID_ARGUMENT);
uint8_t digest[kSHA256_Hash_Length];
memset(&digest[0], 0, sizeof(digest));
ReturnErrorOnFailure(Hash_SHA256(msg, msg_length, &digest[0]));
#if defined(MBEDTLS_ECDSA_C)
CHIP_ERROR error = CHIP_NO_ERROR;
int result = 0;
mbedtls_mpi r, s;
mbedtls_mpi_init(&r);
mbedtls_mpi_init(&s);
const mbedtls_ecp_keypair * keypair = to_const_keypair(&mKeypair);
mbedtls_ecdsa_context ecdsa_ctxt;
mbedtls_ecdsa_init(&ecdsa_ctxt);
result = mbedtls_ecdsa_from_keypair(&ecdsa_ctxt, keypair);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
result = mbedtls_ecdsa_sign(&ecdsa_ctxt.CHIP_CRYPTO_PAL_PRIVATE(grp), &r, &s, &ecdsa_ctxt.CHIP_CRYPTO_PAL_PRIVATE(d),
Uint8::to_const_uchar(digest), sizeof(digest), CryptoRNG, nullptr);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
VerifyOrExit((mbedtls_mpi_size(&r) <= kP256_FE_Length) && (mbedtls_mpi_size(&s) <= kP256_FE_Length),
error = CHIP_ERROR_INTERNAL);
// Concatenate r and s to output. Sizes were checked above.
result = mbedtls_mpi_write_binary(&r, out_signature.Bytes() + 0u, kP256_FE_Length);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
result = mbedtls_mpi_write_binary(&s, out_signature.Bytes() + kP256_FE_Length, kP256_FE_Length);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
VerifyOrExit(out_signature.SetLength(kP256_ECDSA_Signature_Length_Raw) == CHIP_NO_ERROR, error = CHIP_ERROR_INTERNAL);
exit:
keypair = nullptr;
mbedtls_ecdsa_free(&ecdsa_ctxt);
mbedtls_mpi_free(&s);
mbedtls_mpi_free(&r);
_log_mbedTLS_error(result);
return error;
#else
return CHIP_ERROR_NOT_IMPLEMENTED;
#endif
}
CHIP_ERROR P256PublicKey::ECDSA_validate_msg_signature(const uint8_t * msg, const size_t msg_length,
const P256ECDSASignature & signature) const
{
#if defined(MBEDTLS_ECDSA_C)
VerifyOrReturnError((msg != nullptr) && (msg_length > 0), CHIP_ERROR_INVALID_ARGUMENT);
uint8_t digest[kSHA256_Hash_Length];
memset(&digest[0], 0, sizeof(digest));
ReturnErrorOnFailure(Hash_SHA256(msg, msg_length, &digest[0]));
return ECDSA_validate_hash_signature(&digest[0], sizeof(digest), signature);
#else
return CHIP_ERROR_NOT_IMPLEMENTED;
#endif
}
CHIP_ERROR P256PublicKey::ECDSA_validate_hash_signature(const uint8_t * hash, const size_t hash_length,
const P256ECDSASignature & signature) const
{
#if defined(MBEDTLS_ECDSA_C)
VerifyOrReturnError(hash != nullptr, CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrReturnError(hash_length == kSHA256_Hash_Length, CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrReturnError(signature.Length() == kP256_ECDSA_Signature_Length_Raw, CHIP_ERROR_INVALID_ARGUMENT);
CHIP_ERROR error = CHIP_NO_ERROR;
int result = 0;
mbedtls_mpi r, s;
mbedtls_mpi_init(&r);
mbedtls_mpi_init(&s);
mbedtls_ecp_keypair keypair;
mbedtls_ecp_keypair_init(&keypair);
mbedtls_ecdsa_context ecdsa_ctxt;
mbedtls_ecdsa_init(&ecdsa_ctxt);
result = mbedtls_ecp_group_load(&keypair.CHIP_CRYPTO_PAL_PRIVATE(grp), MapECPGroupId(Type()));
VerifyOrExit(result == 0, error = CHIP_ERROR_INVALID_ARGUMENT);
result = mbedtls_ecp_point_read_binary(&keypair.CHIP_CRYPTO_PAL_PRIVATE(grp), &keypair.CHIP_CRYPTO_PAL_PRIVATE(Q),
Uint8::to_const_uchar(*this), Length());
VerifyOrExit(result == 0, error = CHIP_ERROR_INVALID_ARGUMENT);
result = mbedtls_ecdsa_from_keypair(&ecdsa_ctxt, &keypair);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
// Read the <r, s> big nums from the signature
result = mbedtls_mpi_read_binary(&r, Uint8::to_const_uchar(signature.ConstBytes()) + 0u, kP256_FE_Length);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
result = mbedtls_mpi_read_binary(&s, Uint8::to_const_uchar(signature.ConstBytes()) + kP256_FE_Length, kP256_FE_Length);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
result = mbedtls_ecdsa_verify(&ecdsa_ctxt.CHIP_CRYPTO_PAL_PRIVATE(grp), Uint8::to_const_uchar(hash), hash_length,
&ecdsa_ctxt.CHIP_CRYPTO_PAL_PRIVATE(Q), &r, &s);
VerifyOrExit(result == 0, error = CHIP_ERROR_INVALID_SIGNATURE);
exit:
mbedtls_ecdsa_free(&ecdsa_ctxt);
mbedtls_ecp_keypair_free(&keypair);
mbedtls_mpi_free(&s);
mbedtls_mpi_free(&r);
_log_mbedTLS_error(result);
return error;
#else
return CHIP_ERROR_NOT_IMPLEMENTED;
#endif
}
CHIP_ERROR P256Keypair::ECDH_derive_secret(const P256PublicKey & remote_public_key, P256ECDHDerivedSecret & out_secret) const
{
#if defined(MBEDTLS_ECDH_C)
CHIP_ERROR error = CHIP_NO_ERROR;
int result = 0;
size_t secret_length = (out_secret.Length() == 0) ? out_secret.Capacity() : out_secret.Length();
mbedtls_ecp_group ecp_grp;
mbedtls_ecp_group_init(&ecp_grp);
mbedtls_mpi mpi_secret;
mbedtls_mpi_init(&mpi_secret);
mbedtls_ecp_point ecp_pubkey;
mbedtls_ecp_point_init(&ecp_pubkey);
const mbedtls_ecp_keypair * keypair = to_const_keypair(&mKeypair);
VerifyOrExit(mInitialized, error = CHIP_ERROR_WELL_UNINITIALIZED);
result = mbedtls_ecp_group_load(&ecp_grp, MapECPGroupId(remote_public_key.Type()));
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
result =
mbedtls_ecp_point_read_binary(&ecp_grp, &ecp_pubkey, Uint8::to_const_uchar(remote_public_key), remote_public_key.Length());
VerifyOrExit(result == 0, error = CHIP_ERROR_INVALID_ARGUMENT);
result =
mbedtls_ecdh_compute_shared(&ecp_grp, &mpi_secret, &ecp_pubkey, &keypair->CHIP_CRYPTO_PAL_PRIVATE(d), CryptoRNG, nullptr);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
result = mbedtls_mpi_write_binary(&mpi_secret, Uint8::to_uchar(out_secret), secret_length);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
SuccessOrExit(out_secret.SetLength(secret_length));
exit:
keypair = nullptr;
mbedtls_ecp_group_free(&ecp_grp);
mbedtls_mpi_free(&mpi_secret);
mbedtls_ecp_point_free(&ecp_pubkey);
_log_mbedTLS_error(result);
return error;
#else
return CHIP_ERROR_NOT_IMPLEMENTED;
#endif
}
void ClearSecretData(uint8_t * buf, size_t len)
{
mbedtls_platform_zeroize(buf, len);
}
// THE BELOW IS FROM `third_party/openthread/repo/third_party/mbedtls/repo/library/constant_time.c` since
// mbedtls_ct_memcmp is not available on Linux somehow :(
int mbedtls_ct_memcmp_copy(const void * a, const void * b, size_t n)
{
size_t i;
volatile const unsigned char * A = (volatile const unsigned char *) a;
volatile const unsigned char * B = (volatile const unsigned char *) b;
volatile unsigned char diff = 0;
for (i = 0; i < n; i++)
{
/* Read volatile data in order before computing diff.
* This avoids IAR compiler warning:
* 'the order of volatile accesses is undefined ..' */
unsigned char x = A[i], y = B[i];
diff |= x ^ y;
}
return ((int) diff);
}
bool IsBufferContentEqualConstantTime(const void * a, const void * b, size_t n)
{
return mbedtls_ct_memcmp_copy(a, b, n) == 0;
}
CHIP_ERROR P256Keypair::Initialize(ECPKeyTarget key_target)
{
CHIP_ERROR error = CHIP_NO_ERROR;
int result = 0;
size_t pubkey_size = 0;
Clear();
mbedtls_ecp_group_id group = MapECPGroupId(mPublicKey.Type());
mbedtls_ecp_keypair * keypair = to_keypair(&mKeypair);
mbedtls_ecp_keypair_init(keypair);
result = mbedtls_ecp_gen_key(group, keypair, CryptoRNG, nullptr);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
result =
mbedtls_ecp_point_write_binary(&keypair->CHIP_CRYPTO_PAL_PRIVATE(grp), &keypair->CHIP_CRYPTO_PAL_PRIVATE(Q),
MBEDTLS_ECP_PF_UNCOMPRESSED, &pubkey_size, Uint8::to_uchar(mPublicKey), mPublicKey.Length());
VerifyOrExit(result == 0, error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(pubkey_size == mPublicKey.Length(), error = CHIP_ERROR_INVALID_ARGUMENT);
keypair = nullptr;
mInitialized = true;
exit:
if (keypair != nullptr)
{
mbedtls_ecp_keypair_free(keypair);
keypair = nullptr;
}
_log_mbedTLS_error(result);
return error;
}
CHIP_ERROR P256Keypair::Serialize(P256SerializedKeypair & output) const
{
const mbedtls_ecp_keypair * keypair = to_const_keypair(&mKeypair);
size_t len = output.Length() == 0 ? output.Capacity() : output.Length();
Encoding::BufferWriter bbuf(output, len);
uint8_t privkey[kP256_PrivateKey_Length];
CHIP_ERROR error = CHIP_NO_ERROR;
int result = 0;
bbuf.Put(mPublicKey, mPublicKey.Length());
VerifyOrExit(bbuf.Available() == sizeof(privkey), error = CHIP_ERROR_INTERNAL);
VerifyOrExit(mbedtls_mpi_size(&keypair->CHIP_CRYPTO_PAL_PRIVATE(d)) <= bbuf.Available(), error = CHIP_ERROR_INTERNAL);
result = mbedtls_mpi_write_binary(&keypair->CHIP_CRYPTO_PAL_PRIVATE(d), Uint8::to_uchar(privkey), sizeof(privkey));
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
bbuf.Put(privkey, sizeof(privkey));
VerifyOrExit(bbuf.Fit(), error = CHIP_ERROR_BUFFER_TOO_SMALL);
output.SetLength(bbuf.Needed());
exit:
ClearSecretData(privkey, sizeof(privkey));
_log_mbedTLS_error(result);
return error;
}
CHIP_ERROR P256Keypair::Deserialize(P256SerializedKeypair & input)
{
Encoding::BufferWriter bbuf(mPublicKey, mPublicKey.Length());
int result = 0;
CHIP_ERROR error = CHIP_NO_ERROR;
Clear();
mbedtls_ecp_keypair * keypair = to_keypair(&mKeypair);
mbedtls_ecp_keypair_init(keypair);
result = mbedtls_ecp_group_load(&keypair->CHIP_CRYPTO_PAL_PRIVATE(grp), MapECPGroupId(mPublicKey.Type()));
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
VerifyOrExit(input.Length() == mPublicKey.Length() + kP256_PrivateKey_Length, error = CHIP_ERROR_INVALID_ARGUMENT);
bbuf.Put((const uint8_t *) input, mPublicKey.Length());
VerifyOrExit(bbuf.Fit(), error = CHIP_ERROR_NO_MEMORY);
result = mbedtls_ecp_point_read_binary(&keypair->CHIP_CRYPTO_PAL_PRIVATE(grp), &keypair->CHIP_CRYPTO_PAL_PRIVATE(Q),
Uint8::to_const_uchar(mPublicKey), mPublicKey.Length());
VerifyOrExit(result == 0, error = CHIP_ERROR_INVALID_ARGUMENT);
{
const uint8_t * privkey = Uint8::to_const_uchar(input) + mPublicKey.Length();
result = mbedtls_mpi_read_binary(&keypair->CHIP_CRYPTO_PAL_PRIVATE(d), privkey, kP256_PrivateKey_Length);
VerifyOrExit(result == 0, error = CHIP_ERROR_INVALID_ARGUMENT);
}
mInitialized = true;
exit:
_log_mbedTLS_error(result);
return error;
}
void P256Keypair::Clear()
{
if (mInitialized)
{
mbedtls_ecp_keypair * keypair = to_keypair(&mKeypair);
mbedtls_ecp_keypair_free(keypair);
mInitialized = false;
}
}
P256Keypair::~P256Keypair()
{
Clear();
}
CHIP_ERROR P256Keypair::NewCertificateSigningRequest(uint8_t * out_csr, size_t & csr_length) const
{
#if defined(MBEDTLS_X509_CSR_WRITE_C)
CHIP_ERROR error = CHIP_NO_ERROR;
int result = 0;
size_t out_length;
mbedtls_x509write_csr csr;
mbedtls_x509write_csr_init(&csr);
mbedtls_pk_context pk;
pk.CHIP_CRYPTO_PAL_PRIVATE(pk_info) = mbedtls_pk_info_from_type(MBEDTLS_PK_ECKEY);
pk.CHIP_CRYPTO_PAL_PRIVATE(pk_ctx) = to_keypair(&mKeypair);
VerifyOrExit(pk.CHIP_CRYPTO_PAL_PRIVATE(pk_info) != nullptr, error = CHIP_ERROR_INTERNAL);
VerifyOrExit(mInitialized, error = CHIP_ERROR_WELL_UNINITIALIZED);
mbedtls_x509write_csr_set_key(&csr, &pk);
mbedtls_x509write_csr_set_md_alg(&csr, MBEDTLS_MD_SHA256);
// TODO: mbedTLS CSR parser fails if the subject name is not set (or if empty).
// CHIP Spec doesn't specify the subject name that can be used.
// Figure out the correct value and update this code.
result = mbedtls_x509write_csr_set_subject_name(&csr, "O=CSR");
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
result = mbedtls_x509write_csr_der(&csr, out_csr, csr_length, CryptoRNG, nullptr);
VerifyOrExit(result > 0, error = CHIP_ERROR_INTERNAL);
VerifyOrExit(CanCastTo<size_t>(result), error = CHIP_ERROR_INTERNAL);
out_length = static_cast<size_t>(result);
result = 0;
VerifyOrExit(out_length <= csr_length, error = CHIP_ERROR_INTERNAL);
if (csr_length != out_length)
{
// mbedTLS API writes the CSR at the end of the provided buffer.
// Let's move it to the start of the buffer.
size_t offset = csr_length - out_length;
memmove(out_csr, &out_csr[offset], out_length);
}
csr_length = out_length;
exit:
mbedtls_x509write_csr_free(&csr);
_log_mbedTLS_error(result);
return error;
#else
ChipLogError(Crypto, "MBEDTLS_X509_CSR_WRITE_C is not enabled. CSR cannot be created");
return CHIP_ERROR_UNSUPPORTED_CHIP_FEATURE;
#endif
}
CHIP_ERROR VerifyCertificateSigningRequest(const uint8_t * csr_buf, size_t csr_length, P256PublicKey & pubkey)
{
#if defined(MBEDTLS_X509_CSR_PARSE_C)
ReturnErrorOnFailure(VerifyCertificateSigningRequestFormat(csr_buf, csr_length));
// TODO: For some embedded targets, mbedTLS library doesn't have mbedtls_x509_csr_parse_der, and mbedtls_x509_csr_parse_free.
// Taking a step back, embedded targets likely will not process CSR requests. Adding this action item to reevaluate
// this if there's a need for this processing for embedded targets.
CHIP_ERROR error = CHIP_NO_ERROR;
size_t pubkey_size = 0;
mbedtls_ecp_keypair * keypair = nullptr;
P256ECDSASignature signature;
MutableByteSpan out_raw_sig_span(signature.Bytes(), signature.Capacity());
mbedtls_x509_csr csr;
mbedtls_x509_csr_init(&csr);
int result = mbedtls_x509_csr_parse_der(&csr, csr_buf, csr_length);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
// Verify the signature algorithm and public key type
VerifyOrExit(csr.CHIP_CRYPTO_PAL_PRIVATE(sig_md) == MBEDTLS_MD_SHA256, error = CHIP_ERROR_UNSUPPORTED_SIGNATURE_TYPE);
VerifyOrExit(csr.CHIP_CRYPTO_PAL_PRIVATE(sig_pk) == MBEDTLS_PK_ECDSA, error = CHIP_ERROR_WRONG_KEY_TYPE);
keypair = mbedtls_pk_ec(csr.CHIP_CRYPTO_PAL_PRIVATE_X509(pk));
// Copy the public key from the CSR
result = mbedtls_ecp_point_write_binary(&keypair->CHIP_CRYPTO_PAL_PRIVATE(grp), &keypair->CHIP_CRYPTO_PAL_PRIVATE(Q),
MBEDTLS_ECP_PF_UNCOMPRESSED, &pubkey_size, Uint8::to_uchar(pubkey), pubkey.Length());
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
VerifyOrExit(pubkey_size == pubkey.Length(), error = CHIP_ERROR_INTERNAL);
// Convert DER signature to raw signature
error = EcdsaAsn1SignatureToRaw(kP256_FE_Length,
ByteSpan{ csr.CHIP_CRYPTO_PAL_PRIVATE(sig).CHIP_CRYPTO_PAL_PRIVATE_X509(p),
csr.CHIP_CRYPTO_PAL_PRIVATE(sig).CHIP_CRYPTO_PAL_PRIVATE_X509(len) },
out_raw_sig_span);
VerifyOrExit(error == CHIP_NO_ERROR, error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(out_raw_sig_span.size() == (kP256_FE_Length * 2), error = CHIP_ERROR_INTERNAL);
signature.SetLength(out_raw_sig_span.size());
// Verify the signature using the public key
error = pubkey.ECDSA_validate_msg_signature(csr.CHIP_CRYPTO_PAL_PRIVATE_X509(cri).CHIP_CRYPTO_PAL_PRIVATE_X509(p),
csr.CHIP_CRYPTO_PAL_PRIVATE_X509(cri).CHIP_CRYPTO_PAL_PRIVATE_X509(len), signature);
SuccessOrExit(error);
exit:
mbedtls_x509_csr_free(&csr);
_log_mbedTLS_error(result);
return error;
#else
ChipLogError(Crypto, "MBEDTLS_X509_CSR_PARSE_C is not enabled. CSR cannot be parsed");
return CHIP_ERROR_UNSUPPORTED_CHIP_FEATURE;
#endif
}
typedef struct Spake2p_Context
{
mbedtls_ecp_group curve;
mbedtls_ecp_point M;
mbedtls_ecp_point N;
mbedtls_ecp_point X;
mbedtls_ecp_point Y;
mbedtls_ecp_point L;
mbedtls_ecp_point Z;
mbedtls_ecp_point V;
mbedtls_mpi w0;
mbedtls_mpi w1;
mbedtls_mpi xy;
mbedtls_mpi tempbn;
} Spake2p_Context;
static inline Spake2p_Context * to_inner_spake2p_context(Spake2pOpaqueContext * context)
{
return SafePointerCast<Spake2p_Context *>(context);
}
CHIP_ERROR Spake2p_P256_SHA256_HKDF_HMAC::InitInternal()
{
CHIP_ERROR error = CHIP_NO_ERROR;
int result = 0;
Spake2p_Context * context = to_inner_spake2p_context(&mSpake2pContext);
memset(context, 0, sizeof(Spake2p_Context));
mbedtls_ecp_group_init(&context->curve);
result = mbedtls_ecp_group_load(&context->curve, MBEDTLS_ECP_DP_SECP256R1);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
VerifyOrExit(mbedtls_md_info_from_type(MBEDTLS_MD_SHA256) != nullptr, error = CHIP_ERROR_INTERNAL);
mbedtls_ecp_point_init(&context->M);
mbedtls_ecp_point_init(&context->N);
mbedtls_ecp_point_init(&context->X);
mbedtls_ecp_point_init(&context->Y);
mbedtls_ecp_point_init(&context->L);
mbedtls_ecp_point_init(&context->V);
mbedtls_ecp_point_init(&context->Z);
M = &context->M;
N = &context->N;
X = &context->X;
Y = &context->Y;
L = &context->L;
V = &context->V;
Z = &context->Z;
mbedtls_mpi_init(&context->w0);
mbedtls_mpi_init(&context->w1);
mbedtls_mpi_init(&context->xy);
mbedtls_mpi_init(&context->tempbn);
w0 = &context->w0;
w1 = &context->w1;
xy = &context->xy;
tempbn = &context->tempbn;
G = &context->curve.G;
order = &context->curve.N;
return error;
exit:
_log_mbedTLS_error(result);
Clear();
return error;
}
void Spake2p_P256_SHA256_HKDF_HMAC::Clear()
{
VerifyOrReturn(state != CHIP_SPAKE2P_STATE::PREINIT);
Spake2p_Context * context = to_inner_spake2p_context(&mSpake2pContext);
mbedtls_ecp_point_free(&context->M);
mbedtls_ecp_point_free(&context->N);
mbedtls_ecp_point_free(&context->X);
mbedtls_ecp_point_free(&context->Y);
mbedtls_ecp_point_free(&context->L);
mbedtls_ecp_point_free(&context->Z);
mbedtls_ecp_point_free(&context->V);
mbedtls_mpi_free(&context->w0);
mbedtls_mpi_free(&context->w1);
mbedtls_mpi_free(&context->xy);
mbedtls_mpi_free(&context->tempbn);
mbedtls_ecp_group_free(&context->curve);
state = CHIP_SPAKE2P_STATE::PREINIT;
}
CHIP_ERROR Spake2p_P256_SHA256_HKDF_HMAC::Mac(const uint8_t * key, size_t key_len, const uint8_t * in, size_t in_len,
MutableByteSpan & out_span)
{
HMAC_sha hmac;
VerifyOrReturnError(out_span.size() >= kSHA256_Hash_Length, CHIP_ERROR_BUFFER_TOO_SMALL);
ReturnErrorOnFailure(hmac.HMAC_SHA256(key, key_len, in, in_len, out_span.data(), kSHA256_Hash_Length));
out_span = out_span.SubSpan(0, kSHA256_Hash_Length);
return CHIP_NO_ERROR;
}
CHIP_ERROR Spake2p_P256_SHA256_HKDF_HMAC::MacVerify(const uint8_t * key, size_t key_len, const uint8_t * mac, size_t mac_len,
const uint8_t * in, size_t in_len)
{
CHIP_ERROR error = CHIP_NO_ERROR;
int result = 0;
uint8_t computed_mac[kSHA256_Hash_Length];
MutableByteSpan computed_mac_span{ computed_mac };
VerifyOrExit(mac_len == kSHA256_Hash_Length, error = CHIP_ERROR_INVALID_ARGUMENT);
SuccessOrExit(error = Mac(key, key_len, in, in_len, computed_mac_span));
VerifyOrExit(computed_mac_span.size() == mac_len, error = CHIP_ERROR_INTERNAL);
VerifyOrExit(IsBufferContentEqualConstantTime(mac, computed_mac, kSHA256_Hash_Length), error = CHIP_ERROR_INTERNAL);
exit:
_log_mbedTLS_error(result);
return error;
}
CHIP_ERROR Spake2p_P256_SHA256_HKDF_HMAC::FELoad(const uint8_t * in, size_t in_len, void * fe)
{
CHIP_ERROR error = CHIP_NO_ERROR;
int result = 0;
result = mbedtls_mpi_read_binary((mbedtls_mpi *) fe, Uint8::to_const_uchar(in), in_len);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
result = mbedtls_mpi_mod_mpi((mbedtls_mpi *) fe, (mbedtls_mpi *) fe, (const mbedtls_mpi *) order);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
exit:
_log_mbedTLS_error(result);
return error;
}
CHIP_ERROR Spake2p_P256_SHA256_HKDF_HMAC::FEWrite(const void * fe, uint8_t * out, size_t out_len)
{
if (mbedtls_mpi_write_binary((const mbedtls_mpi *) fe, Uint8::to_uchar(out), out_len) != 0)
{
return CHIP_ERROR_INTERNAL;
}
return CHIP_NO_ERROR;
}
CHIP_ERROR Spake2p_P256_SHA256_HKDF_HMAC::FEGenerate(void * fe)
{
CHIP_ERROR error = CHIP_NO_ERROR;
int result = 0;
Spake2p_Context * context = to_inner_spake2p_context(&mSpake2pContext);
result = mbedtls_ecp_gen_privkey(&context->curve, (mbedtls_mpi *) fe, CryptoRNG, nullptr);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
exit:
_log_mbedTLS_error(result);
return error;
}
CHIP_ERROR Spake2p_P256_SHA256_HKDF_HMAC::FEMul(void * fer, const void * fe1, const void * fe2)
{
CHIP_ERROR error = CHIP_NO_ERROR;
int result = 0;
result = mbedtls_mpi_mul_mpi((mbedtls_mpi *) fer, (const mbedtls_mpi *) fe1, (const mbedtls_mpi *) fe2);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
result = mbedtls_mpi_mod_mpi((mbedtls_mpi *) fer, (mbedtls_mpi *) fer, (const mbedtls_mpi *) order);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
exit:
_log_mbedTLS_error(result);
return error;
}
CHIP_ERROR Spake2p_P256_SHA256_HKDF_HMAC::PointLoad(const uint8_t * in, size_t in_len, void * R)
{
Spake2p_Context * context = to_inner_spake2p_context(&mSpake2pContext);
if (mbedtls_ecp_point_read_binary(&context->curve, (mbedtls_ecp_point *) R, Uint8::to_const_uchar(in), in_len) != 0)
{
return CHIP_ERROR_INTERNAL;
}
return CHIP_NO_ERROR;
}
CHIP_ERROR Spake2p_P256_SHA256_HKDF_HMAC::PointWrite(const void * R, uint8_t * out, size_t out_len)
{
memset(out, 0, out_len);
size_t mbedtls_out_len = out_len;
Spake2p_Context * context = to_inner_spake2p_context(&mSpake2pContext);
if (mbedtls_ecp_point_write_binary(&context->curve, (const mbedtls_ecp_point *) R, MBEDTLS_ECP_PF_UNCOMPRESSED,
&mbedtls_out_len, Uint8::to_uchar(out), out_len) != 0)
{
return CHIP_ERROR_INTERNAL;
}
return CHIP_NO_ERROR;
}
CHIP_ERROR Spake2p_P256_SHA256_HKDF_HMAC::PointMul(void * R, const void * P1, const void * fe1)
{
Spake2p_Context * context = to_inner_spake2p_context(&mSpake2pContext);
if (mbedtls_ecp_mul(&context->curve, (mbedtls_ecp_point *) R, (const mbedtls_mpi *) fe1, (const mbedtls_ecp_point *) P1,
CryptoRNG, nullptr) != 0)
{
return CHIP_ERROR_INTERNAL;
}
return CHIP_NO_ERROR;
}
CHIP_ERROR Spake2p_P256_SHA256_HKDF_HMAC::PointAddMul(void * R, const void * P1, const void * fe1, const void * P2,
const void * fe2)
{
Spake2p_Context * context = to_inner_spake2p_context(&mSpake2pContext);
if (mbedtls_ecp_muladd(&context->curve, (mbedtls_ecp_point *) R, (const mbedtls_mpi *) fe1, (const mbedtls_ecp_point *) P1,
(const mbedtls_mpi *) fe2, (const mbedtls_ecp_point *) P2) != 0)
{
return CHIP_ERROR_INTERNAL;
}
return CHIP_NO_ERROR;
}
CHIP_ERROR Spake2p_P256_SHA256_HKDF_HMAC::PointInvert(void * R)
{
mbedtls_ecp_point * Rp = (mbedtls_ecp_point *) R;
Spake2p_Context * context = to_inner_spake2p_context(&mSpake2pContext);
if (mbedtls_mpi_sub_mpi(&Rp->CHIP_CRYPTO_PAL_PRIVATE(Y), &context->curve.P, &Rp->CHIP_CRYPTO_PAL_PRIVATE(Y)) != 0)
{
return CHIP_ERROR_INTERNAL;
}
return CHIP_NO_ERROR;
}
CHIP_ERROR Spake2p_P256_SHA256_HKDF_HMAC::PointCofactorMul(void * R)
{
return CHIP_NO_ERROR;
}
CHIP_ERROR Spake2p_P256_SHA256_HKDF_HMAC::ComputeL(uint8_t * Lout, size_t * L_len, const uint8_t * w1in, size_t w1in_len)
{
CHIP_ERROR error = CHIP_NO_ERROR;
int result = 0;
mbedtls_ecp_group curve;
mbedtls_mpi w1_bn;
mbedtls_ecp_point Ltemp;
mbedtls_ecp_group_init(&curve);
mbedtls_mpi_init(&w1_bn);
mbedtls_ecp_point_init(&Ltemp);
result = mbedtls_ecp_group_load(&curve, MBEDTLS_ECP_DP_SECP256R1);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
result = mbedtls_mpi_read_binary(&w1_bn, Uint8::to_const_uchar(w1in), w1in_len);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
result = mbedtls_mpi_mod_mpi(&w1_bn, &w1_bn, &curve.N);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
result = mbedtls_ecp_mul(&curve, &Ltemp, &w1_bn, &curve.G, CryptoRNG, nullptr);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
memset(Lout, 0, *L_len);
result = mbedtls_ecp_point_write_binary(&curve, &Ltemp, MBEDTLS_ECP_PF_UNCOMPRESSED, L_len, Uint8::to_uchar(Lout), *L_len);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
exit:
_log_mbedTLS_error(result);
mbedtls_ecp_point_free(&Ltemp);
mbedtls_mpi_free(&w1_bn);
mbedtls_ecp_group_free(&curve);
return error;
}
CHIP_ERROR Spake2p_P256_SHA256_HKDF_HMAC::PointIsValid(void * R)
{
Spake2p_Context * context = to_inner_spake2p_context(&mSpake2pContext);
if (mbedtls_ecp_check_pubkey(&context->curve, (mbedtls_ecp_point *) R) != 0)
{
return CHIP_ERROR_INTERNAL;
}
return CHIP_NO_ERROR;
}
namespace {
#if defined(MBEDTLS_X509_CRT_PARSE_C)
bool IsTimeGreaterThanEqual(const mbedtls_x509_time * const timeA, const mbedtls_x509_time * const timeB)
{
// checks if two values are different and if yes, then returns first > second.
#define RETURN_STRICTLY_GREATER_IF_DIFFERENT(component) \
{ \
auto valueA = timeA->CHIP_CRYPTO_PAL_PRIVATE_X509(component); \
auto valueB = timeB->CHIP_CRYPTO_PAL_PRIVATE_X509(component); \
\
if (valueA != valueB) \
{ \
return valueA > valueB; \
} \
}
RETURN_STRICTLY_GREATER_IF_DIFFERENT(year);
RETURN_STRICTLY_GREATER_IF_DIFFERENT(mon);
RETURN_STRICTLY_GREATER_IF_DIFFERENT(day);
RETURN_STRICTLY_GREATER_IF_DIFFERENT(hour);
RETURN_STRICTLY_GREATER_IF_DIFFERENT(min);
RETURN_STRICTLY_GREATER_IF_DIFFERENT(sec);
// all above are equal
return true;
}
CHIP_ERROR IsCertificateValidAtIssuance(const mbedtls_x509_crt * candidateCertificate, const mbedtls_x509_crt * issuerCertificate)
{
mbedtls_x509_time candidateNotBeforeTime = candidateCertificate->CHIP_CRYPTO_PAL_PRIVATE_X509(valid_from);
mbedtls_x509_time issuerNotBeforeTime = issuerCertificate->CHIP_CRYPTO_PAL_PRIVATE_X509(valid_from);
mbedtls_x509_time issuerNotAfterTime = issuerCertificate->CHIP_CRYPTO_PAL_PRIVATE_X509(valid_to);
// check if candidateCertificate is issued at or after issuerCertificate's notBefore timestamp
VerifyOrReturnError(IsTimeGreaterThanEqual(&candidateNotBeforeTime, &issuerNotBeforeTime), CHIP_ERROR_CERT_EXPIRED);
// check if candidateCertificate is issued at or before issuerCertificate's notAfter timestamp
VerifyOrReturnError(IsTimeGreaterThanEqual(&issuerNotAfterTime, &candidateNotBeforeTime), CHIP_ERROR_CERT_EXPIRED);
return CHIP_NO_ERROR;
}
int CallbackForCustomValidityCheck(void * data, mbedtls_x509_crt * crt, int depth, uint32_t * flags)
{
mbedtls_x509_crt * leafCert = reinterpret_cast<mbedtls_x509_crt *>(data);
mbedtls_x509_crt * issuerCert = crt;
// Ignore any time validy error performed by the standard mbedTLS code.
*flags &= ~(static_cast<uint32_t>(MBEDTLS_X509_BADCERT_EXPIRED | MBEDTLS_X509_BADCERT_FUTURE));
// Verify that the leaf certificate has a notBefore time valid within the validity period of the issuerCertificate.
// Note that this callback is invoked for each certificate in the chain.
if (IsCertificateValidAtIssuance(leafCert, issuerCert) != CHIP_NO_ERROR)
{
return MBEDTLS_ERR_X509_INVALID_DATE;
}
return 0;
}
constexpr uint8_t sOID_AttributeType_CommonName[] = { 0x55, 0x04, 0x03 };
constexpr uint8_t sOID_AttributeType_MatterVendorId[] = { 0x2B, 0x06, 0x01, 0x04, 0x01, 0x82, 0xA2, 0x7C, 0x02, 0x01 };
constexpr uint8_t sOID_AttributeType_MatterProductId[] = { 0x2B, 0x06, 0x01, 0x04, 0x01, 0x82, 0xA2, 0x7C, 0x02, 0x02 };
constexpr uint8_t sOID_SigAlgo_ECDSAWithSHA256[] = { 0x2A, 0x86, 0x48, 0xCE, 0x3D, 0x04, 0x03, 0x02 };
constexpr uint8_t sOID_Extension_BasicConstraints[] = { 0x55, 0x1D, 0x13 };
constexpr uint8_t sOID_Extension_KeyUsage[] = { 0x55, 0x1D, 0x0F };
constexpr uint8_t sOID_Extension_SubjectKeyIdentifier[] = { 0x55, 0x1D, 0x0E };
constexpr uint8_t sOID_Extension_AuthorityKeyIdentifier[] = { 0x55, 0x1D, 0x23 };
/**
* Compares an mbedtls_asn1_buf structure (oidBuf) to a reference OID represented as uint8_t array (oid).
*/
#define OID_CMP(oid, oidBuf) \
((MBEDTLS_ASN1_OID == (oidBuf).CHIP_CRYPTO_PAL_PRIVATE_X509(tag)) && \
(sizeof(oid) == (oidBuf).CHIP_CRYPTO_PAL_PRIVATE_X509(len)) && \
(memcmp((oid), (oidBuf).CHIP_CRYPTO_PAL_PRIVATE_X509(p), (oidBuf).CHIP_CRYPTO_PAL_PRIVATE_X509(len)) == 0))
#endif // defined(MBEDTLS_X509_CRT_PARSE_C)
} // anonymous namespace
CHIP_ERROR VerifyAttestationCertificateFormat(const ByteSpan & cert, AttestationCertType certType)
{
#if defined(MBEDTLS_X509_CRT_PARSE_C)
CHIP_ERROR error = CHIP_NO_ERROR;
int result = 0;
mbedtls_x509_crt mbed_cert;
unsigned char * p = nullptr;
const unsigned char * end = nullptr;
size_t len = 0;
bool extBasicPresent = false;
bool extKeyUsagePresent = false;
VerifyOrReturnError(!cert.empty(), CHIP_ERROR_INVALID_ARGUMENT);
mbedtls_x509_crt_init(&mbed_cert);
result = mbedtls_x509_crt_parse(&mbed_cert, Uint8::to_const_uchar(cert.data()), cert.size());
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
// "version" value is 1 higher than the actual encoded value.
VerifyOrExit(mbed_cert.CHIP_CRYPTO_PAL_PRIVATE_X509(version) - 1 == 2, error = CHIP_ERROR_INTERNAL);
// Verify signature algorithms is ECDSA with SHA256.
VerifyOrExit(OID_CMP(sOID_SigAlgo_ECDSAWithSHA256, mbed_cert.CHIP_CRYPTO_PAL_PRIVATE_X509(sig_oid)),
error = CHIP_ERROR_INTERNAL);
// Verify public key presence and format.
{
Crypto::P256PublicKey pubkey;
SuccessOrExit(error = ExtractPubkeyFromX509Cert(cert, pubkey));
}
p = mbed_cert.CHIP_CRYPTO_PAL_PRIVATE_X509(v3_ext).CHIP_CRYPTO_PAL_PRIVATE_X509(p);
end = p + mbed_cert.CHIP_CRYPTO_PAL_PRIVATE_X509(v3_ext).CHIP_CRYPTO_PAL_PRIVATE_X509(len);
result = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
while (p < end)
{
mbedtls_x509_buf extOID = { 0, 0, nullptr };
int extCritical = 0;
result = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
/* Get extension ID */
result = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_OID);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
extOID.CHIP_CRYPTO_PAL_PRIVATE_X509(tag) = MBEDTLS_ASN1_OID;
extOID.CHIP_CRYPTO_PAL_PRIVATE_X509(len) = len;
extOID.CHIP_CRYPTO_PAL_PRIVATE_X509(p) = p;
p += len;
/* Get optional critical */
result = mbedtls_asn1_get_bool(&p, end, &extCritical);
VerifyOrExit(result == 0 || result == MBEDTLS_ERR_ASN1_UNEXPECTED_TAG, error = CHIP_ERROR_INTERNAL);
/* Data should be octet string type */
result = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_OCTET_STRING);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
if (OID_CMP(sOID_Extension_BasicConstraints, extOID))
{
int isCA = 0;
int pathLen = -1;
unsigned char * seqStart = p;
VerifyOrExit(extCritical, error = CHIP_ERROR_INTERNAL);
extBasicPresent = true;
result = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
if (len > 0)
{
result = mbedtls_asn1_get_bool(&p, end, &isCA);
VerifyOrExit(result == 0 || result == MBEDTLS_ERR_ASN1_UNEXPECTED_TAG, error = CHIP_ERROR_INTERNAL);
if (p != seqStart + len)
{
result = mbedtls_asn1_get_int(&p, end, &pathLen);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
}
}
if (certType == AttestationCertType::kDAC)
{
VerifyOrExit(!isCA && pathLen == -1, error = CHIP_ERROR_INTERNAL);
}
else if (certType == AttestationCertType::kPAI)
{
VerifyOrExit(isCA && pathLen == 0, error = CHIP_ERROR_INTERNAL);
}
else
{
VerifyOrExit(isCA && (pathLen == -1 || pathLen == 0 || pathLen == 1), error = CHIP_ERROR_INTERNAL);
}
}
else if (OID_CMP(sOID_Extension_KeyUsage, extOID))
{
mbedtls_x509_bitstring bs = { 0, 0, nullptr };
unsigned int keyUsage = 0;
VerifyOrExit(extCritical, error = CHIP_ERROR_INTERNAL);
extKeyUsagePresent = true;
result = mbedtls_asn1_get_bitstring(&p, p + len, &bs);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
for (size_t i = 0; i < bs.CHIP_CRYPTO_PAL_PRIVATE_X509(len) && i < sizeof(unsigned int); i++)
{
keyUsage |= static_cast<unsigned int>(bs.CHIP_CRYPTO_PAL_PRIVATE_X509(p)[i]) << (8 * i);
}
if (certType == AttestationCertType::kDAC)
{
// SHALL only have the digitalSignature bit set.
VerifyOrExit(keyUsage == MBEDTLS_X509_KU_DIGITAL_SIGNATURE, error = CHIP_ERROR_INTERNAL);
}
else
{
bool keyCertSignFlag = keyUsage & MBEDTLS_X509_KU_KEY_CERT_SIGN;
bool crlSignFlag = keyUsage & MBEDTLS_X509_KU_CRL_SIGN;
bool otherFlags =
keyUsage & ~(MBEDTLS_X509_KU_CRL_SIGN | MBEDTLS_X509_KU_KEY_CERT_SIGN | MBEDTLS_X509_KU_DIGITAL_SIGNATURE);
VerifyOrExit(keyCertSignFlag && crlSignFlag && !otherFlags, error = CHIP_ERROR_INTERNAL);
}
}
else
{
p += len;
}
}
// Verify basic and key usage extensions are present.
VerifyOrExit(extBasicPresent && extKeyUsagePresent, error = CHIP_ERROR_INTERNAL);
// Verify that SKID and AKID extensions are present.
{
uint8_t kidBuf[kSubjectKeyIdentifierLength];
MutableByteSpan kid(kidBuf);
SuccessOrExit(error = ExtractSKIDFromX509Cert(cert, kid));
if (certType == AttestationCertType::kDAC || certType == AttestationCertType::kPAI)
{
// Mandatory extension for DAC and PAI certs.
SuccessOrExit(error = ExtractAKIDFromX509Cert(cert, kid));
}
}
exit:
_log_mbedTLS_error(result);
mbedtls_x509_crt_free(&mbed_cert);
#else
(void) cert;
(void) certType;
CHIP_ERROR error = CHIP_ERROR_NOT_IMPLEMENTED;
#endif // defined(MBEDTLS_X509_CRT_PARSE_C)
return error;
}
CHIP_ERROR ValidateCertificateChain(const uint8_t * rootCertificate, size_t rootCertificateLen, const uint8_t * caCertificate,
size_t caCertificateLen, const uint8_t * leafCertificate, size_t leafCertificateLen,
CertificateChainValidationResult & result)
{
#if defined(MBEDTLS_X509_CRT_PARSE_C)
CHIP_ERROR error = CHIP_NO_ERROR;
mbedtls_x509_crt certChain;
mbedtls_x509_crt rootCert;
int mbedResult;
uint32_t flags = 0;
result = CertificateChainValidationResult::kInternalFrameworkError;
VerifyOrReturnError(rootCertificate != nullptr && rootCertificateLen != 0,
(result = CertificateChainValidationResult::kRootArgumentInvalid, CHIP_ERROR_INVALID_ARGUMENT));
VerifyOrReturnError(leafCertificate != nullptr && leafCertificateLen != 0,
(result = CertificateChainValidationResult::kLeafArgumentInvalid, CHIP_ERROR_INVALID_ARGUMENT));
mbedtls_x509_crt_init(&certChain);
mbedtls_x509_crt_init(&rootCert);
/* Start of chain */
mbedResult = mbedtls_x509_crt_parse(&certChain, Uint8::to_const_uchar(leafCertificate), leafCertificateLen);
VerifyOrExit(mbedResult == 0, (result = CertificateChainValidationResult::kLeafFormatInvalid, error = CHIP_ERROR_INTERNAL));
/* Add the intermediate to the chain, if present */
if (caCertificate != nullptr && caCertificateLen > 0)
{
mbedResult = mbedtls_x509_crt_parse(&certChain, Uint8::to_const_uchar(caCertificate), caCertificateLen);
VerifyOrExit(mbedResult == 0, (result = CertificateChainValidationResult::kICAFormatInvalid, error = CHIP_ERROR_INTERNAL));
}
/* Parse the root cert */
mbedResult = mbedtls_x509_crt_parse(&rootCert, Uint8::to_const_uchar(rootCertificate), rootCertificateLen);
VerifyOrExit(mbedResult == 0, (result = CertificateChainValidationResult::kRootFormatInvalid, error = CHIP_ERROR_INTERNAL));
/* Verify the chain against the root */
mbedResult =
mbedtls_x509_crt_verify(&certChain, &rootCert, nullptr, nullptr, &flags, CallbackForCustomValidityCheck, &certChain);
switch (mbedResult)
{
case 0:
VerifyOrExit(flags == 0, (result = CertificateChainValidationResult::kInternalFrameworkError, error = CHIP_ERROR_INTERNAL));
result = CertificateChainValidationResult::kSuccess;
break;
case MBEDTLS_ERR_X509_INVALID_DATE:
case MBEDTLS_ERR_X509_CERT_VERIFY_FAILED:
result = CertificateChainValidationResult::kChainInvalid;
error = CHIP_ERROR_CERT_NOT_TRUSTED;
break;
default:
SuccessOrExit((result = CertificateChainValidationResult::kInternalFrameworkError, error = CHIP_ERROR_INTERNAL));
}
exit:
_log_mbedTLS_error(mbedResult);
mbedtls_x509_crt_free(&certChain);
mbedtls_x509_crt_free(&rootCert);
#else
(void) rootCertificate;
(void) rootCertificateLen;
(void) caCertificate;
(void) caCertificateLen;
(void) leafCertificate;
(void) leafCertificateLen;
(void) result;
CHIP_ERROR error = CHIP_ERROR_NOT_IMPLEMENTED;
#endif // defined(MBEDTLS_X509_CRT_PARSE_C)
return error;
}
CHIP_ERROR IsCertificateValidAtIssuance(const ByteSpan & candidateCertificate, const ByteSpan & issuerCertificate)
{
#if defined(MBEDTLS_X509_CRT_PARSE_C)
CHIP_ERROR error = CHIP_NO_ERROR;
mbedtls_x509_crt mbedCandidateCertificate;
mbedtls_x509_crt mbedIssuerCertificate;
int result;
VerifyOrReturnError(!candidateCertificate.empty() && !issuerCertificate.empty(), CHIP_ERROR_INVALID_ARGUMENT);
mbedtls_x509_crt_init(&mbedCandidateCertificate);
mbedtls_x509_crt_init(&mbedIssuerCertificate);
result = mbedtls_x509_crt_parse(&mbedCandidateCertificate, Uint8::to_const_uchar(candidateCertificate.data()),
candidateCertificate.size());
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
result =
mbedtls_x509_crt_parse(&mbedIssuerCertificate, Uint8::to_const_uchar(issuerCertificate.data()), issuerCertificate.size());
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
// Verify that the candidateCertificate has a notBefore time valid within the validity period of the issuerCertificate.
SuccessOrExit(error = IsCertificateValidAtIssuance(&mbedCandidateCertificate, &mbedIssuerCertificate));
exit:
_log_mbedTLS_error(result);
mbedtls_x509_crt_free(&mbedCandidateCertificate);
mbedtls_x509_crt_free(&mbedIssuerCertificate);
#else
(void) candidateCertificate;
(void) issuerCertificate;
CHIP_ERROR error = CHIP_ERROR_NOT_IMPLEMENTED;
#endif // defined(MBEDTLS_X509_CRT_PARSE_C)
return error;
}
CHIP_ERROR IsCertificateValidAtCurrentTime(const ByteSpan & certificate)
{
#if defined(MBEDTLS_X509_CRT_PARSE_C)
CHIP_ERROR error = CHIP_NO_ERROR;
mbedtls_x509_crt mbedCertificate;
int result;
VerifyOrReturnError(!certificate.empty(), CHIP_ERROR_INVALID_ARGUMENT);
mbedtls_x509_crt_init(&mbedCertificate);
result = mbedtls_x509_crt_parse(&mbedCertificate, Uint8::to_const_uchar(certificate.data()), certificate.size());
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
// check if certificate's notBefore timestamp is earlier than or equal to current time.
result = mbedtls_x509_time_is_past(&mbedCertificate.CHIP_CRYPTO_PAL_PRIVATE_X509(valid_from));
VerifyOrExit(result == 1, error = CHIP_ERROR_CERT_EXPIRED);
// check if certificate's notAfter timestamp is later than current time.
result = mbedtls_x509_time_is_future(&mbedCertificate.CHIP_CRYPTO_PAL_PRIVATE_X509(valid_to));
VerifyOrExit(result == 1, error = CHIP_ERROR_CERT_EXPIRED);
exit:
_log_mbedTLS_error(result);
mbedtls_x509_crt_free(&mbedCertificate);
#else
(void) certificate;
CHIP_ERROR error = CHIP_ERROR_NOT_IMPLEMENTED;
#endif // defined(MBEDTLS_X509_CRT_PARSE_C)
return error;
}
CHIP_ERROR ExtractPubkeyFromX509Cert(const ByteSpan & certificate, Crypto::P256PublicKey & pubkey)
{
#if defined(MBEDTLS_X509_CRT_PARSE_C)
CHIP_ERROR error = CHIP_NO_ERROR;
mbedtls_x509_crt mbed_cert;
mbedtls_ecp_keypair * keypair = nullptr;
size_t pubkey_size = 0;
mbedtls_x509_crt_init(&mbed_cert);
int result = mbedtls_x509_crt_parse(&mbed_cert, Uint8::to_const_uchar(certificate.data()), certificate.size());
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
VerifyOrExit(mbedtls_pk_get_type(&(mbed_cert.CHIP_CRYPTO_PAL_PRIVATE_X509(pk))) == MBEDTLS_PK_ECKEY,
error = CHIP_ERROR_INVALID_ARGUMENT);
keypair = mbedtls_pk_ec(mbed_cert.CHIP_CRYPTO_PAL_PRIVATE_X509(pk));
VerifyOrExit(keypair->CHIP_CRYPTO_PAL_PRIVATE(grp).id == MapECPGroupId(pubkey.Type()), error = CHIP_ERROR_INVALID_ARGUMENT);
// Copy the public key from the cert in raw point format
result =
mbedtls_ecp_point_write_binary(&keypair->CHIP_CRYPTO_PAL_PRIVATE(grp), &keypair->CHIP_CRYPTO_PAL_PRIVATE(Q),
MBEDTLS_ECP_PF_UNCOMPRESSED, &pubkey_size, Uint8::to_uchar(pubkey.Bytes()), pubkey.Length());
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
VerifyOrExit(pubkey_size == pubkey.Length(), error = CHIP_ERROR_INTERNAL);
exit:
_log_mbedTLS_error(result);
mbedtls_x509_crt_free(&mbed_cert);
#else
(void) certificate;
(void) pubkey;
CHIP_ERROR error = CHIP_ERROR_NOT_IMPLEMENTED;
#endif // defined(MBEDTLS_X509_CRT_PARSE_C)
return error;
}
namespace {
CHIP_ERROR ExtractKIDFromX509Cert(bool extractSKID, const ByteSpan & certificate, MutableByteSpan & kid)
{
#if defined(MBEDTLS_X509_CRT_PARSE_C)
CHIP_ERROR error = CHIP_ERROR_NOT_FOUND;
mbedtls_x509_crt mbed_cert;
unsigned char * p = nullptr;
const unsigned char * end = nullptr;
size_t len = 0;
mbedtls_x509_crt_init(&mbed_cert);
int result = mbedtls_x509_crt_parse(&mbed_cert, Uint8::to_const_uchar(certificate.data()), certificate.size());
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
// TODO: The mbedTLS team is working on supporting SKID and AKID extensions processing.
// Once it is supported, this code should be updated.
p = mbed_cert.CHIP_CRYPTO_PAL_PRIVATE_X509(v3_ext).CHIP_CRYPTO_PAL_PRIVATE_X509(p);
end = mbed_cert.CHIP_CRYPTO_PAL_PRIVATE_X509(v3_ext).CHIP_CRYPTO_PAL_PRIVATE_X509(p) +
mbed_cert.CHIP_CRYPTO_PAL_PRIVATE_X509(v3_ext).CHIP_CRYPTO_PAL_PRIVATE_X509(len);
result = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE);
VerifyOrExit(result == 0, error = CHIP_ERROR_WRONG_CERT_TYPE);
while (p < end)
{
result = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE);
VerifyOrExit(result == 0, error = CHIP_ERROR_WRONG_CERT_TYPE);
result = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_OID);
VerifyOrExit(result == 0, error = CHIP_ERROR_WRONG_CERT_TYPE);
mbedtls_x509_buf extOID = { MBEDTLS_ASN1_OID, len, p };
bool extractCurrentExtSKID = extractSKID && OID_CMP(sOID_Extension_SubjectKeyIdentifier, extOID);
bool extractCurrentExtAKID = !extractSKID && OID_CMP(sOID_Extension_AuthorityKeyIdentifier, extOID);
p += len;
int is_critical = 0;
result = mbedtls_asn1_get_bool(&p, end, &is_critical);
VerifyOrExit(result == 0 || result == MBEDTLS_ERR_ASN1_UNEXPECTED_TAG, error = CHIP_ERROR_WRONG_CERT_TYPE);
result = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_OCTET_STRING);
VerifyOrExit(result == 0, error = CHIP_ERROR_WRONG_CERT_TYPE);
if (extractCurrentExtSKID || extractCurrentExtAKID)
{
if (extractCurrentExtSKID)
{
result = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_OCTET_STRING);
VerifyOrExit(result == 0, error = CHIP_ERROR_WRONG_CERT_TYPE);
}
else
{
result = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE);
VerifyOrExit(result == 0, error = CHIP_ERROR_WRONG_CERT_TYPE);
result = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONTEXT_SPECIFIC);
VerifyOrExit(result == 0, error = CHIP_ERROR_WRONG_CERT_TYPE);
// Other optional fields, authorityCertIssuer and authorityCertSerialNumber,
// will be skipped if present.
}
VerifyOrExit(len == kSubjectKeyIdentifierLength, error = CHIP_ERROR_WRONG_CERT_TYPE);
VerifyOrExit(len <= kid.size(), error = CHIP_ERROR_BUFFER_TOO_SMALL);
memcpy(kid.data(), p, len);
if (kid.size() > len)
{
kid.reduce_size(len);
}
ExitNow(error = CHIP_NO_ERROR);
break;
}
p += len;
}
exit:
_log_mbedTLS_error(result);
mbedtls_x509_crt_free(&mbed_cert);
#else
(void) certificate;
(void) kid;
CHIP_ERROR error = CHIP_ERROR_NOT_IMPLEMENTED;
#endif // defined(MBEDTLS_X509_CRT_PARSE_C)
return error;
}
} // namespace
CHIP_ERROR ExtractSKIDFromX509Cert(const ByteSpan & certificate, MutableByteSpan & skid)
{
return ExtractKIDFromX509Cert(true, certificate, skid);
}
CHIP_ERROR ExtractAKIDFromX509Cert(const ByteSpan & certificate, MutableByteSpan & akid)
{
return ExtractKIDFromX509Cert(false, certificate, akid);
}
CHIP_ERROR ExtractVIDPIDFromX509Cert(const ByteSpan & certificate, AttestationCertVidPid & vidpid)
{
#if defined(MBEDTLS_X509_CRT_PARSE_C)
CHIP_ERROR error = CHIP_NO_ERROR;
mbedtls_x509_crt mbed_cert;
mbedtls_asn1_named_data * dnIterator = nullptr;
AttestationCertVidPid vidpidFromCN;
mbedtls_x509_crt_init(&mbed_cert);
int result = mbedtls_x509_crt_parse(&mbed_cert, Uint8::to_const_uchar(certificate.data()), certificate.size());
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
for (dnIterator = &mbed_cert.CHIP_CRYPTO_PAL_PRIVATE_X509(subject); dnIterator != nullptr;
dnIterator = dnIterator->CHIP_CRYPTO_PAL_PRIVATE_X509(next))
{
DNAttrType attrType = DNAttrType::kUnspecified;
if (OID_CMP(sOID_AttributeType_CommonName, dnIterator->CHIP_CRYPTO_PAL_PRIVATE_X509(oid)))
{
attrType = DNAttrType::kCommonName;
}
else if (OID_CMP(sOID_AttributeType_MatterVendorId, dnIterator->CHIP_CRYPTO_PAL_PRIVATE_X509(oid)))
{
attrType = DNAttrType::kMatterVID;
}
else if (OID_CMP(sOID_AttributeType_MatterProductId, dnIterator->CHIP_CRYPTO_PAL_PRIVATE_X509(oid)))
{
attrType = DNAttrType::kMatterPID;
}
size_t val_len = dnIterator->CHIP_CRYPTO_PAL_PRIVATE_X509(val).CHIP_CRYPTO_PAL_PRIVATE_X509(len);
uint8_t * val_p = dnIterator->CHIP_CRYPTO_PAL_PRIVATE_X509(val).CHIP_CRYPTO_PAL_PRIVATE_X509(p);
error = ExtractVIDPIDFromAttributeString(attrType, ByteSpan(val_p, val_len), vidpid, vidpidFromCN);
SuccessOrExit(error);
}
// If Matter Attributes were not found use values extracted from the CN Attribute,
// which might be uninitialized as well.
if (!vidpid.Initialized())
{
vidpid = vidpidFromCN;
}
exit:
_log_mbedTLS_error(result);
mbedtls_x509_crt_free(&mbed_cert);
#else
(void) certificate;
(void) vidpid;
CHIP_ERROR error = CHIP_ERROR_NOT_IMPLEMENTED;
#endif // defined(MBEDTLS_X509_CRT_PARSE_C)
return error;
}
} // namespace Crypto
} // namespace chip