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pigweed / third_party / github / project-chip / connectedhomeip / 03efab5f3221455886dd33552b40156741d63c89 / . / src / platform / silabs / efr32 / CHIPCryptoPALPsaEfr32.cpp
blob: 9948017c4d3f945173026baa884e7dd05dff91cd [file] [log] [blame]
/*
*
* Copyright (c) 2020-2023 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
* PSA Crypto API based implementation of CHIP crypto primitives
* with Silicon Labs SDK modifications
*/
#include <crypto/CHIPCryptoPAL.h>
#include <type_traits>
// Include version header to get configuration information
#include <mbedtls/version.h>
#if !defined(MBEDTLS_PSA_CRYPTO_C)
#error "This implementation needs PSA Crypto"
#endif
#if !defined(MBEDTLS_USE_PSA_CRYPTO)
#error "This implementation requires that PSA Crypto keys can be used for CSR generation"
#endif
#include "psa/crypto.h"
// Go straight for the driver wrappers for speed on plaintext keys
extern "C" {
#include "psa_crypto_core.h"
#include "psa_crypto_driver_wrappers.h"
}
// Includes needed for SPAKE2+ ECP operations
#include <mbedtls/bignum.h>
#include <mbedtls/ecp.h>
// Includes needed for certificate parsing
#if defined(MBEDTLS_X509_CRT_PARSE_C)
#include <mbedtls/x509_crt.h>
#endif // defined(MBEDTLS_X509_CRT_PARSE_C)
#include <mbedtls/md.h>
#include <mbedtls/x509.h>
#include <mbedtls/x509_csr.h>
#if defined(MBEDTLS_ERROR_C)
#include <mbedtls/error.h>
#endif // defined(MBEDTLS_ERROR_C)
#include <lib/core/CHIPSafeCasts.h>
#include <lib/support/BufferWriter.h>
#include <lib/support/BytesToHex.h>
#include <lib/support/CHIPArgParser.hpp>
#include <lib/support/CHIPMem.h>
#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 {
using chip::Platform::MemoryCalloc;
using chip::Platform::MemoryFree;
#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
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 void _log_PSA_error(psa_status_t status)
{
if (status != 0)
{
// Error codes defined in 16-bit negative hex numbers. Ease lookup by printing likewise
ChipLogError(Crypto, "PSA error: %ld", status);
}
}
static bool _isValidTagLength(size_t tag_length)
{
if (tag_length == 8 || tag_length == 12 || tag_length == 16)
{
return true;
}
return false;
}
/**
* @brief Compare two times
*
* @param t1 First time to compare
* @param t2 Second time to compare
* @return int 0 If both times are idential to the second, -1 if t1 < t2, 1 if t1 > t2.
*/
static int timeCompare(mbedtls_x509_time * t1, mbedtls_x509_time * t2)
{
VerifyOrReturnValue(t1->year >= t2->year, -1);
VerifyOrReturnValue(t1->year <= t2->year, 1);
// Same year
VerifyOrReturnValue(t1->mon >= t2->mon, -1);
VerifyOrReturnValue(t1->mon <= t2->mon, 1);
// Same month
VerifyOrReturnValue(t1->day >= t2->day, -1);
VerifyOrReturnValue(t1->day <= t2->day, 1);
// Same day
VerifyOrReturnValue(t1->hour >= t2->hour, -1);
VerifyOrReturnValue(t1->hour <= t2->hour, 1);
// Same hour
VerifyOrReturnValue(t1->min >= t2->min, -1);
VerifyOrReturnValue(t1->min <= t2->min, 1);
// Same minute
VerifyOrReturnValue(t1->sec >= t2->sec, -1);
VerifyOrReturnValue(t1->sec <= t2->sec, 1);
// Same second
return 0;
}
CHIP_ERROR AES_CCM_encrypt(const uint8_t * plaintext, size_t plaintext_length, const uint8_t * aad, size_t aad_length,
const Aes128KeyHandle & key, const uint8_t * nonce, size_t nonce_length, uint8_t * ciphertext,
uint8_t * tag, size_t tag_length)
{
CHIP_ERROR error = CHIP_NO_ERROR;
psa_status_t status = PSA_ERROR_BAD_STATE;
psa_key_attributes_t attr = PSA_KEY_ATTRIBUTES_INIT;
size_t output_length = 0;
uint8_t * buffer = nullptr;
bool allocated_buffer = false;
VerifyOrExit(_isValidTagLength(tag_length), error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(nonce != nullptr, error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(nonce_length > 0, error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(CanCastTo<int>(nonce_length), error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(tag != nullptr, error = CHIP_ERROR_INVALID_ARGUMENT);
// If the ciphertext and tag outputs aren't a contiguous buffer, the PSA API requires buffer copying
if (Uint8::to_uchar(ciphertext) + plaintext_length != Uint8::to_uchar(tag))
{
buffer = (uint8_t *) MemoryCalloc(1, plaintext_length + tag_length);
allocated_buffer = true;
VerifyOrExit(buffer != nullptr, error = CHIP_ERROR_NO_MEMORY);
}
psa_crypto_init();
psa_set_key_type(&attr, PSA_KEY_TYPE_AES);
psa_set_key_bits(&attr, sizeof(Aes128KeyByteArray) * 8);
psa_set_key_algorithm(&attr, PSA_ALG_AEAD_WITH_AT_LEAST_THIS_LENGTH_TAG(PSA_ALG_CCM, 8));
psa_set_key_usage_flags(&attr, PSA_KEY_USAGE_ENCRYPT);
status = psa_driver_wrapper_aead_encrypt(
&attr, key.As<Aes128KeyByteArray>(), sizeof(Aes128KeyByteArray), PSA_ALG_AEAD_WITH_SHORTENED_TAG(PSA_ALG_CCM, tag_length),
Uint8::to_const_uchar(nonce), nonce_length, Uint8::to_const_uchar(aad), aad_length, Uint8::to_const_uchar(plaintext),
plaintext_length, allocated_buffer ? buffer : ciphertext, plaintext_length + tag_length, &output_length);
VerifyOrExit(status == PSA_SUCCESS, error = CHIP_ERROR_INTERNAL);
VerifyOrExit(output_length == plaintext_length + tag_length, error = CHIP_ERROR_INTERNAL);
if (allocated_buffer)
{
memcpy(Uint8::to_uchar(ciphertext), buffer, plaintext_length);
memcpy(Uint8::to_uchar(tag), buffer + plaintext_length, tag_length);
memset(buffer, 0, plaintext_length + tag_length);
}
exit:
if (allocated_buffer)
{
MemoryFree(buffer);
}
psa_reset_key_attributes(&attr);
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 Aes128KeyHandle & key, const uint8_t * nonce,
size_t nonce_length, uint8_t * plaintext)
{
CHIP_ERROR error = CHIP_NO_ERROR;
psa_status_t status = PSA_ERROR_BAD_STATE;
psa_key_attributes_t attr = PSA_KEY_ATTRIBUTES_INIT;
size_t output_length = 0;
uint8_t * buffer = nullptr;
bool allocated_buffer = false;
VerifyOrExit(_isValidTagLength(tag_length), error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(tag != nullptr, error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(nonce != nullptr, error = CHIP_ERROR_INVALID_ARGUMENT);
VerifyOrExit(nonce_length > 0, error = CHIP_ERROR_INVALID_ARGUMENT);
// If the ciphertext and tag outputs aren't a contiguous buffer, the PSA API requires buffer copying
if (Uint8::to_const_uchar(ciphertext) + ciphertext_len != Uint8::to_const_uchar(tag))
{
buffer = (uint8_t *) MemoryCalloc(1, ciphertext_len + tag_length);
allocated_buffer = true;
VerifyOrExit(buffer != nullptr, error = CHIP_ERROR_NO_MEMORY);
}
psa_crypto_init();
psa_set_key_type(&attr, PSA_KEY_TYPE_AES);
psa_set_key_bits(&attr, sizeof(Aes128KeyByteArray) * 8);
psa_set_key_algorithm(&attr, PSA_ALG_AEAD_WITH_AT_LEAST_THIS_LENGTH_TAG(PSA_ALG_CCM, 8));
psa_set_key_usage_flags(&attr, PSA_KEY_USAGE_DECRYPT);
if (allocated_buffer)
{
memcpy(buffer, ciphertext, ciphertext_len);
memcpy(buffer + ciphertext_len, tag, tag_length);
}
status = psa_driver_wrapper_aead_decrypt(
&attr, key.As<Aes128KeyByteArray>(), sizeof(Aes128KeyByteArray), PSA_ALG_AEAD_WITH_SHORTENED_TAG(PSA_ALG_CCM, tag_length),
Uint8::to_const_uchar(nonce), nonce_length, Uint8::to_const_uchar(aad), aad_len, allocated_buffer ? buffer : ciphertext,
ciphertext_len + tag_length, plaintext, ciphertext_len, &output_length);
if (allocated_buffer)
{
memset(buffer, 0, ciphertext_len + tag_length);
}
VerifyOrExit(status == PSA_SUCCESS, error = CHIP_ERROR_INTERNAL);
VerifyOrExit(output_length == ciphertext_len, error = CHIP_ERROR_INTERNAL);
exit:
if (allocated_buffer)
{
MemoryFree(buffer);
}
psa_reset_key_attributes(&attr);
return error;
}
CHIP_ERROR Hash_SHA256(const uint8_t * data, const size_t data_length, uint8_t * out_buffer)
{
size_t output_length = 0;
psa_crypto_init();
const psa_status_t result =
psa_hash_compute(PSA_ALG_SHA_256, data, data_length, out_buffer, PSA_HASH_LENGTH(PSA_ALG_SHA_256), &output_length);
VerifyOrReturnError(result == PSA_SUCCESS, CHIP_ERROR_INTERNAL);
VerifyOrReturnError(output_length == PSA_HASH_LENGTH(PSA_ALG_SHA_256), CHIP_ERROR_INTERNAL);
return CHIP_NO_ERROR;
}
CHIP_ERROR Hash_SHA1(const uint8_t * data, const size_t data_length, uint8_t * out_buffer)
{
size_t output_length = 0;
psa_crypto_init();
const psa_status_t result =
psa_hash_compute(PSA_ALG_SHA_1, data, data_length, out_buffer, PSA_HASH_LENGTH(PSA_ALG_SHA_1), &output_length);
VerifyOrReturnError(result == PSA_SUCCESS, CHIP_ERROR_INTERNAL);
VerifyOrReturnError(output_length == PSA_HASH_LENGTH(PSA_ALG_SHA_1), CHIP_ERROR_INTERNAL);
return CHIP_NO_ERROR;
}
static_assert(kMAX_Hash_SHA256_Context_Size >= sizeof(psa_hash_operation_t),
"kMAX_Hash_SHA256_Context_Size is too small for the size of underlying psa_hash_operation_t");
static inline psa_hash_operation_t * to_inner_hash_sha256_context(HashSHA256OpaqueContext * context)
{
return SafePointerCast<psa_hash_operation_t *>(context);
}
Hash_SHA256_stream::Hash_SHA256_stream(void)
{
psa_hash_operation_t * context = to_inner_hash_sha256_context(&mContext);
const psa_hash_operation_t initial_context = PSA_HASH_OPERATION_INIT;
memcpy(context, &initial_context, sizeof(psa_hash_operation_t));
}
Hash_SHA256_stream::~Hash_SHA256_stream(void)
{
psa_hash_operation_t * context = to_inner_hash_sha256_context(&mContext);
psa_hash_abort(context);
Clear();
}
CHIP_ERROR Hash_SHA256_stream::Begin(void)
{
psa_crypto_init();
psa_hash_operation_t * context = to_inner_hash_sha256_context(&mContext);
*context = PSA_HASH_OPERATION_INIT;
const psa_status_t result = psa_hash_setup(context, PSA_ALG_SHA_256);
VerifyOrReturnError(result == PSA_SUCCESS, CHIP_ERROR_INTERNAL);
return CHIP_NO_ERROR;
}
CHIP_ERROR Hash_SHA256_stream::AddData(const ByteSpan data)
{
psa_hash_operation_t * context = to_inner_hash_sha256_context(&mContext);
const psa_status_t result = psa_hash_update(context, Uint8::to_const_uchar(data.data()), data.size());
VerifyOrReturnError(result == PSA_SUCCESS, CHIP_ERROR_INTERNAL);
return CHIP_NO_ERROR;
}
CHIP_ERROR Hash_SHA256_stream::GetDigest(MutableByteSpan & out_buffer)
{
CHIP_ERROR result = CHIP_NO_ERROR;
psa_status_t status = PSA_ERROR_BAD_STATE;
size_t output_length = 0;
psa_hash_operation_t * context = to_inner_hash_sha256_context(&mContext);
VerifyOrReturnError(out_buffer.size() >= kSHA256_Hash_Length, CHIP_ERROR_BUFFER_TOO_SMALL);
// Clone the context first since calculating the digest finishes the operation
psa_hash_operation_t digest_context = PSA_HASH_OPERATION_INIT;
status = psa_hash_clone(context, &digest_context);
VerifyOrReturnError(status == PSA_SUCCESS, CHIP_ERROR_INTERNAL);
// Calculate digest on the cloned context
status = psa_hash_finish(&digest_context, Uint8::to_uchar(out_buffer.data()), out_buffer.size(), &output_length);
VerifyOrExit(status == PSA_SUCCESS, result = CHIP_ERROR_INTERNAL);
VerifyOrExit(output_length == PSA_HASH_LENGTH(PSA_ALG_SHA_256), result = CHIP_ERROR_INTERNAL);
exit:
psa_hash_abort(&digest_context);
return result;
}
CHIP_ERROR Hash_SHA256_stream::Finish(MutableByteSpan & out_buffer)
{
psa_hash_operation_t * context = to_inner_hash_sha256_context(&mContext);
size_t output_length = 0;
VerifyOrReturnError(out_buffer.size() >= kSHA256_Hash_Length, CHIP_ERROR_BUFFER_TOO_SMALL);
const psa_status_t status = psa_hash_finish(context, Uint8::to_uchar(out_buffer.data()), out_buffer.size(), &output_length);
VerifyOrReturnError(status == PSA_SUCCESS, CHIP_ERROR_INTERNAL);
VerifyOrReturnError(output_length == PSA_HASH_LENGTH(PSA_ALG_SHA_256), CHIP_ERROR_INTERNAL);
return CHIP_NO_ERROR;
}
void Hash_SHA256_stream::Clear(void)
{
psa_hash_operation_t * context = to_inner_hash_sha256_context(&mContext);
psa_hash_abort(context);
}
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);
CHIP_ERROR error = CHIP_NO_ERROR;
psa_status_t status = PSA_ERROR_BAD_STATE;
psa_key_derivation_operation_t operation = PSA_KEY_DERIVATION_OPERATION_INIT;
psa_crypto_init();
status = psa_key_derivation_setup(&operation, PSA_ALG_HKDF(PSA_ALG_SHA_256));
VerifyOrExit(status == PSA_SUCCESS, error = CHIP_ERROR_INTERNAL);
if (salt_length > 0)
{
status =
psa_key_derivation_input_bytes(&operation, PSA_KEY_DERIVATION_INPUT_SALT, Uint8::to_const_uchar(salt), salt_length);
VerifyOrExit(status == PSA_SUCCESS, error = CHIP_ERROR_INTERNAL);
}
status =
psa_key_derivation_input_bytes(&operation, PSA_KEY_DERIVATION_INPUT_SECRET, Uint8::to_const_uchar(secret), secret_length);
VerifyOrExit(status == PSA_SUCCESS, error = CHIP_ERROR_INTERNAL);
status = psa_key_derivation_input_bytes(&operation, PSA_KEY_DERIVATION_INPUT_INFO, Uint8::to_const_uchar(info), info_length);
VerifyOrExit(status == PSA_SUCCESS, error = CHIP_ERROR_INTERNAL);
status = psa_key_derivation_output_bytes(&operation, out_buffer, out_length);
VerifyOrExit(status == PSA_SUCCESS, error = CHIP_ERROR_INTERNAL);
exit:
psa_key_derivation_abort(&operation);
return 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);
CHIP_ERROR error = CHIP_NO_ERROR;
psa_status_t status = PSA_ERROR_BAD_STATE;
psa_key_attributes_t attr = PSA_KEY_ATTRIBUTES_INIT;
psa_mac_operation_t operation = PSA_MAC_OPERATION_INIT;
size_t output_length = 0;
psa_crypto_init();
psa_set_key_type(&attr, PSA_KEY_TYPE_HMAC);
psa_set_key_bits(&attr, key_length * 8);
psa_set_key_usage_flags(&attr, PSA_KEY_USAGE_SIGN_HASH);
psa_set_key_algorithm(&attr, PSA_ALG_HMAC(PSA_ALG_SHA_256));
status = psa_driver_wrapper_mac_compute(&attr, Uint8::to_const_uchar(key), key_length, PSA_ALG_HMAC(PSA_ALG_SHA_256),
Uint8::to_const_uchar(message), message_length, out_buffer, out_length, &output_length);
VerifyOrExit(status == PSA_SUCCESS, error = CHIP_ERROR_INTERNAL);
VerifyOrExit(output_length == PSA_HASH_LENGTH(PSA_ALG_SHA_256), error = CHIP_ERROR_INTERNAL);
exit:
psa_mac_abort(&operation);
psa_reset_key_attributes(&attr);
return 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)
{
// TODO: replace inlined algorithm with usage of the PSA key derivation API once implemented
CHIP_ERROR error = CHIP_NO_ERROR;
psa_status_t status = PSA_ERROR_BAD_STATE;
psa_key_attributes_t attr = PSA_KEY_ATTRIBUTES_INIT;
size_t output_length = 0;
// Align these buffers on the native data size to speed up the XOR
static const size_t hash_size_in_native =
((PSA_HASH_LENGTH(PSA_ALG_SHA_256) + sizeof(unsigned int) - 1) / sizeof(unsigned int));
static_assert(hash_size_in_native * sizeof(unsigned int) >= PSA_HASH_LENGTH(PSA_ALG_SHA_256));
unsigned int md1_buffer[hash_size_in_native];
unsigned int work_buffer[hash_size_in_native];
uint8_t * md1 = (uint8_t *) md1_buffer;
uint8_t * work = (uint8_t *) work_buffer;
size_t use_len;
unsigned char * out_p = output;
uint8_t * U1 = (uint8_t *) MemoryCalloc(1, slen + 4);
VerifyOrExit(U1 != nullptr, error = CHIP_ERROR_NO_MEMORY);
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);
psa_crypto_init();
psa_set_key_type(&attr, PSA_KEY_TYPE_HMAC);
psa_set_key_bits(&attr, plen * 8);
psa_set_key_usage_flags(&attr, PSA_KEY_USAGE_SIGN_HASH);
psa_set_key_algorithm(&attr, PSA_ALG_HMAC(PSA_ALG_SHA_256));
// Start with initializing the salt + counter
memcpy(U1, salt, slen);
U1[slen] = 0;
U1[slen + 1] = 0;
U1[slen + 2] = 0;
U1[slen + 3] = 1;
// Loop until we have generated the requested key length
while (key_length)
{
// U1 ends up in work
status = psa_driver_wrapper_mac_compute(&attr, password, plen, PSA_ALG_HMAC(PSA_ALG_SHA_256), U1, slen + 4, work,
PSA_HASH_LENGTH(PSA_ALG_SHA_256), &output_length);
VerifyOrExit(status == PSA_SUCCESS, error = CHIP_ERROR_INTERNAL);
VerifyOrExit(output_length == PSA_HASH_LENGTH(PSA_ALG_SHA_256), error = CHIP_ERROR_INTERNAL);
memcpy(md1, work, PSA_HASH_LENGTH(PSA_ALG_SHA_256));
for (size_t i = 1; i < iteration_count; i++)
{
// U2 ends up in md1
//
status = psa_driver_wrapper_mac_compute(&attr, password, plen, PSA_ALG_HMAC(PSA_ALG_SHA_256), md1, sizeof(md1_buffer),
md1, sizeof(md1_buffer), &output_length);
VerifyOrExit(status == PSA_SUCCESS, error = CHIP_ERROR_INTERNAL);
VerifyOrExit(output_length == PSA_HASH_LENGTH(PSA_ALG_SHA_256), error = CHIP_ERROR_INTERNAL);
// U1 xor U2
//
for (size_t j = 0; j < hash_size_in_native; j++)
{
work_buffer[j] ^= md1_buffer[j];
}
}
use_len = (key_length < PSA_HASH_LENGTH(PSA_ALG_SHA_256)) ? key_length : PSA_HASH_LENGTH(PSA_ALG_SHA_256);
memcpy(out_p, work, use_len);
key_length -= (uint32_t) use_len;
out_p += use_len;
for (size_t i = 4; i > 0; i--)
{
if (++U1[slen + i - 1] != 0)
{
break;
}
}
}
exit:
MemoryFree(U1);
psa_reset_key_attributes(&attr);
return error;
}
CHIP_ERROR add_entropy_source(entropy_source fn_source, void * p_source, size_t threshold)
{
// PSA Crypto has its own entropy and doesn't support an override mechanism
(void) fn_source;
(void) p_source;
(void) threshold;
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);
psa_crypto_init();
const psa_status_t result = psa_generate_random(Uint8::to_uchar(out_buffer), out_length);
VerifyOrReturnError(result == PSA_SUCCESS, CHIP_ERROR_INTERNAL);
return CHIP_NO_ERROR;
}
// CryptoRNG's definition is needed to use the mbedTLS-backed SPAKE2+ and certificate operations
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;
}
// Mapping function is used as part of the certificate operations
mbedtls_ecp_group_id MapECPGroupId(SupportedECPKeyTypes keyType)
{
switch (keyType)
{
case SupportedECPKeyTypes::ECP256R1:
return MBEDTLS_ECP_DP_SECP256R1;
default:
return MBEDTLS_ECP_DP_NONE;
}
}
/*******************************************************************************
*
* WARNING: The default (base) implementation of P256Keypair is UNSAFE!
*
* Because of the way CHIPCryptoPAL has evolved, it is dictating how a base
* P256Keypair should behave. This includes:
* * Allowing using a P256 key for both ECDSA and ECDH operations
* * Needing to support copying a key through Serialize()/Deserialize()
* operations. This can't easily be done opaquely on an opaque backend
* without convoluted forms of reference tracking.
* * Not including a way to figure out whether the created key is supposed
* to be ephemeral or long-lived.
* * Needing to support ingestion of specific-format keys through
* Deserialize() (to support e.g. the example DAC provider).
*
* These conditions have lead to the base implementation of this class in this
* crypto backend being backed by a plaintext key buffer instead of opaque key
* references. Usage of the base class is strongly discouraged, and is only
* implemented to support the in-tree examples which instantiate keys of this
* base class.
*
******************************************************************************/
typedef struct
{
uint8_t privkey[32];
size_t bitlen;
} psa_plaintext_ecp_keypair;
static inline psa_plaintext_ecp_keypair * to_keypair(P256KeypairContext * context)
{
return SafePointerCast<psa_plaintext_ecp_keypair *>(context);
}
static inline const psa_plaintext_ecp_keypair * to_const_keypair(const P256KeypairContext * context)
{
return SafePointerCast<const psa_plaintext_ecp_keypair *>(context);
}
CHIP_ERROR P256Keypair::ECDSA_sign_msg(const uint8_t * msg, const size_t msg_length, P256ECDSASignature & out_signature) const
{
CHIP_ERROR error = CHIP_NO_ERROR;
psa_status_t status = PSA_ERROR_BAD_STATE;
psa_key_attributes_t attr = PSA_KEY_ATTRIBUTES_INIT;
size_t output_length = 0;
const psa_plaintext_ecp_keypair * keypair = to_const_keypair(&mKeypair);
VerifyOrExit(mInitialized, error = CHIP_ERROR_WELL_UNINITIALIZED);
VerifyOrExit((msg != nullptr) && (msg_length > 0), error = CHIP_ERROR_INVALID_ARGUMENT);
psa_crypto_init();
psa_set_key_type(&attr, PSA_KEY_TYPE_ECC_KEY_PAIR(PSA_ECC_FAMILY_SECP_R1));
psa_set_key_bits(&attr, keypair->bitlen);
psa_set_key_algorithm(&attr, PSA_ALG_ECDSA(PSA_ALG_SHA_256));
psa_set_key_usage_flags(&attr, PSA_KEY_USAGE_SIGN_MESSAGE);
// use imported key to sign a message
status =
psa_driver_wrapper_sign_message(&attr, keypair->privkey, PSA_BITS_TO_BYTES(keypair->bitlen), PSA_ALG_ECDSA(PSA_ALG_SHA_256),
msg, msg_length, out_signature.Bytes(), out_signature.Capacity(), &output_length);
VerifyOrReturnError(status == PSA_SUCCESS, CHIP_ERROR_INTERNAL);
VerifyOrReturnError(output_length == kP256_ECDSA_Signature_Length_Raw, CHIP_ERROR_INTERNAL);
VerifyOrReturnError(out_signature.SetLength(output_length) == CHIP_NO_ERROR, CHIP_ERROR_INTERNAL);
exit:
_log_PSA_error(status);
psa_reset_key_attributes(&attr);
return error;
}
CHIP_ERROR P256PublicKey::ECDSA_validate_msg_signature(const uint8_t * msg, const size_t msg_length,
const P256ECDSASignature & signature) const
{
CHIP_ERROR error = CHIP_NO_ERROR;
psa_status_t status = PSA_ERROR_BAD_STATE;
psa_key_attributes_t attr = PSA_KEY_ATTRIBUTES_INIT;
VerifyOrExit((msg != nullptr) && (msg_length > 0), error = CHIP_ERROR_INVALID_ARGUMENT);
psa_crypto_init();
psa_set_key_type(&attr, PSA_KEY_TYPE_ECC_PUBLIC_KEY(PSA_ECC_FAMILY_SECP_R1));
psa_set_key_bits(&attr, 256);
psa_set_key_usage_flags(&attr, PSA_KEY_USAGE_VERIFY_MESSAGE);
psa_set_key_algorithm(&attr, PSA_ALG_ECDSA(PSA_ALG_SHA_256));
// use imported key to verify a message
status = psa_driver_wrapper_verify_message(&attr, Uint8::to_const_uchar(*this), Length(), PSA_ALG_ECDSA(PSA_ALG_SHA_256), msg,
msg_length, signature.ConstBytes(), signature.Length());
VerifyOrExit(status == PSA_SUCCESS, error = CHIP_ERROR_INVALID_SIGNATURE);
exit:
_log_PSA_error(status);
psa_reset_key_attributes(&attr);
return error;
}
CHIP_ERROR P256PublicKey::ECDSA_validate_hash_signature(const uint8_t * hash, const size_t hash_length,
const P256ECDSASignature & signature) const
{
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;
psa_status_t status = PSA_ERROR_BAD_STATE;
psa_key_attributes_t attr = PSA_KEY_ATTRIBUTES_INIT;
// Step 1: import public key as volatile
psa_crypto_init();
psa_set_key_type(&attr, PSA_KEY_TYPE_ECC_PUBLIC_KEY(PSA_ECC_FAMILY_SECP_R1));
psa_set_key_bits(&attr, 256);
psa_set_key_usage_flags(&attr, PSA_KEY_USAGE_VERIFY_HASH);
psa_set_key_algorithm(&attr, PSA_ALG_ECDSA(PSA_ALG_SHA_256));
// use imported key to verify a hash
status = psa_driver_wrapper_verify_hash(&attr, Uint8::to_const_uchar(*this), Length(), PSA_ALG_ECDSA(PSA_ALG_SHA_256), hash,
hash_length, signature.ConstBytes(), signature.Length());
VerifyOrExit(status == PSA_SUCCESS, error = CHIP_ERROR_INVALID_SIGNATURE);
exit:
_log_PSA_error(status);
psa_reset_key_attributes(&attr);
return error;
}
CHIP_ERROR P256Keypair::ECDH_derive_secret(const P256PublicKey & remote_public_key, P256ECDHDerivedSecret & out_secret) const
{
// Todo: replace with driver call once key derivation through the driver wrapper has been figured out
CHIP_ERROR error = CHIP_NO_ERROR;
psa_status_t status = PSA_ERROR_BAD_STATE;
mbedtls_svc_key_id_t key_id = 0;
psa_key_attributes_t attr = PSA_KEY_ATTRIBUTES_INIT;
size_t output_length = 0;
const psa_plaintext_ecp_keypair * keypair = to_const_keypair(&mKeypair);
VerifyOrExit(mInitialized, error = CHIP_ERROR_WELL_UNINITIALIZED);
// Step 1: import plaintext key as volatile for ECDH
psa_crypto_init();
psa_set_key_type(&attr, PSA_KEY_TYPE_ECC_KEY_PAIR(PSA_ECC_FAMILY_SECP_R1));
psa_set_key_bits(&attr, keypair->bitlen);
psa_set_key_algorithm(&attr, PSA_ALG_ECDH);
psa_set_key_usage_flags(&attr, PSA_KEY_USAGE_DERIVE);
status = psa_import_key(&attr, keypair->privkey, PSA_BITS_TO_BYTES(keypair->bitlen), &key_id);
VerifyOrExit(status == PSA_SUCCESS, error = CHIP_ERROR_INTERNAL);
// Step 2: do key derivation
status = psa_raw_key_agreement(PSA_ALG_ECDH, key_id, Uint8::to_const_uchar(remote_public_key), remote_public_key.Length(),
out_secret.Bytes(), (out_secret.Length() == 0) ? out_secret.Capacity() : out_secret.Length(),
&output_length);
VerifyOrExit(status == PSA_SUCCESS, error = CHIP_ERROR_INTERNAL);
SuccessOrExit(error = out_secret.SetLength(output_length));
exit:
_log_PSA_error(status);
// Step 3: destroy imported key
psa_reset_key_attributes(&attr);
if (key_id != 0)
{
psa_destroy_key(key_id);
}
return error;
}
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;
psa_status_t status = PSA_ERROR_BAD_STATE;
psa_plaintext_ecp_keypair * keypair = to_keypair(&mKeypair);
size_t output_length;
if (mInitialized)
{
return CHIP_ERROR_INCORRECT_STATE;
}
// Step 1: Generate a volatile new key
psa_key_attributes_t attr = PSA_KEY_ATTRIBUTES_INIT;
psa_crypto_init();
psa_set_key_type(&attr, PSA_KEY_TYPE_ECC_KEY_PAIR(PSA_ECC_FAMILY_SECP_R1));
psa_set_key_bits(&attr, 256);
psa_set_key_algorithm(&attr, PSA_ALG_ECDH);
psa_set_key_usage_flags(&attr, PSA_KEY_USAGE_DERIVE | PSA_KEY_USAGE_EXPORT);
status = psa_driver_wrapper_generate_key(&attr, keypair->privkey, sizeof(keypair->privkey), &output_length);
VerifyOrExit(status == PSA_SUCCESS, error = CHIP_ERROR_INTERNAL);
VerifyOrExit(output_length == kP256_PrivateKey_Length, error = CHIP_ERROR_INTERNAL);
keypair->bitlen = 256;
// Step 2: Export the public key into the pubkey member
status = psa_driver_wrapper_export_public_key(&attr, keypair->privkey, sizeof(keypair->privkey), Uint8::to_uchar(mPublicKey),
mPublicKey.Length(), &output_length);
VerifyOrExit(status == PSA_SUCCESS, error = CHIP_ERROR_INTERNAL);
VerifyOrExit(output_length == kP256_PublicKey_Length, error = CHIP_ERROR_INTERNAL);
exit:
_log_PSA_error(status);
if (error == CHIP_NO_ERROR)
{
mInitialized = true;
}
psa_reset_key_attributes(&attr);
return error;
}
CHIP_ERROR P256Keypair::Serialize(P256SerializedKeypair & output) const
{
CHIP_ERROR error = CHIP_NO_ERROR;
const psa_plaintext_ecp_keypair * keypair = to_const_keypair(&mKeypair);
size_t len = output.Length() == 0 ? output.Capacity() : output.Length();
Encoding::BufferWriter bbuf(output.Bytes(), len);
VerifyOrExit(mInitialized, error = CHIP_ERROR_WELL_UNINITIALIZED);
bbuf.Put(mPublicKey, mPublicKey.Length());
VerifyOrExit(bbuf.Available() == sizeof(keypair->privkey), error = CHIP_ERROR_INTERNAL);
bbuf.Put(keypair->privkey, PSA_BITS_TO_BYTES(keypair->bitlen));
VerifyOrExit(bbuf.Fit(), error = CHIP_ERROR_BUFFER_TOO_SMALL);
output.SetLength(bbuf.Needed());
exit:
return error;
}
CHIP_ERROR P256Keypair::Deserialize(P256SerializedKeypair & input)
{
CHIP_ERROR error = CHIP_NO_ERROR;
psa_plaintext_ecp_keypair * keypair = to_keypair(&mKeypair);
Encoding::BufferWriter bbuf(mPublicKey, mPublicKey.Length());
VerifyOrExit(input.Length() == mPublicKey.Length() + kP256_PrivateKey_Length, error = CHIP_ERROR_INVALID_ARGUMENT);
Clear();
memcpy(keypair->privkey, input.ConstBytes() + mPublicKey.Length(), kP256_PrivateKey_Length);
keypair->bitlen = 256;
bbuf.Put(input.ConstBytes(), mPublicKey.Length());
VerifyOrExit(bbuf.Fit(), error = CHIP_ERROR_NO_MEMORY);
mInitialized = true;
exit:
return error;
}
void P256Keypair::Clear()
{
if (mInitialized)
{
psa_plaintext_ecp_keypair * keypair = to_keypair(&mKeypair);
memset(keypair, 0, sizeof(psa_plaintext_ecp_keypair));
mInitialized = false;
}
}
P256Keypair::~P256Keypair()
{
Clear();
}
CHIP_ERROR P256Keypair::NewCertificateSigningRequest(uint8_t * out_csr, size_t & csr_length) const
{
MutableByteSpan csr(out_csr, csr_length);
CHIP_ERROR err = GenerateCertificateSigningRequest(this, csr);
csr_length = (CHIP_NO_ERROR == err) ? csr.size() : 0;
return err;
}
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(void)
{
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;
}
extern "C" {
#include "em_device.h"
}
#if defined(SEMAILBOX_PRESENT)
// Add inlined optimisation which can use the SE to do point multiplication operations using
// the ECDH primitive as a proxy for scalar multiplication.
extern "C" {
#include "sl_se_manager.h"
#include "sl_se_manager_key_derivation.h"
#include "sl_se_manager_util.h"
#include "sli_se_driver_key_management.h"
#include "sli_se_manager_internal.h"
}
#endif /* SEMAILBOX_PRESENT */
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 defined(SEMAILBOX_PRESENT)
psa_status_t status = PSA_SUCCESS;
uint8_t point[2 * kP256_FE_Length] = { 0 };
uint8_t scalar[kP256_FE_Length] = { 0 };
// This inlined implementation only supports P256, but check assumptions
if (context->curve.id != MBEDTLS_ECP_DP_SECP256R1)
{
return CHIP_ERROR_INVALID_ARGUMENT;
}
/* pull out key info from mbedtls structures */
status = mbedtls_mpi_write_binary((const mbedtls_mpi *) fe1, scalar, sizeof(scalar));
if (status != PSA_SUCCESS)
{
return CHIP_ERROR_INTERNAL;
}
status = mbedtls_mpi_write_binary(&((const mbedtls_ecp_point *) P1)->MBEDTLS_PRIVATE(X), point, kP256_FE_Length);
if (status != PSA_SUCCESS)
{
return CHIP_ERROR_INTERNAL;
}
status =
mbedtls_mpi_write_binary(&((const mbedtls_ecp_point *) P1)->MBEDTLS_PRIVATE(Y), point + kP256_FE_Length, kP256_FE_Length);
if (status != PSA_SUCCESS)
{
return CHIP_ERROR_INTERNAL;
}
{
sl_se_key_descriptor_t priv_desc = { 0 };
sl_se_key_descriptor_t pub_desc = { 0 };
sl_se_key_descriptor_t shared_desc = { 0 };
sl_se_command_context_t cmd_ctx = SL_SE_COMMAND_CONTEXT_INIT;
sl_status_t sl_status = SL_STATUS_FAIL;
// Set private key to scalar
priv_desc.type = SL_SE_KEY_TYPE_ECC_P256;
priv_desc.flags |= SL_SE_KEY_FLAG_ASYMMETRIC_BUFFER_HAS_PRIVATE_KEY;
sli_se_key_descriptor_set_plaintext(&priv_desc, scalar, sizeof(scalar));
// Set public key to point
pub_desc.type = SL_SE_KEY_TYPE_ECC_P256;
pub_desc.flags |= SL_SE_KEY_FLAG_ASYMMETRIC_BUFFER_HAS_PUBLIC_KEY;
sli_se_key_descriptor_set_plaintext(&pub_desc, point, sizeof(point));
// Set output to point
shared_desc.type = SL_SE_KEY_TYPE_SYMMETRIC;
shared_desc.size = sizeof(point);
sli_se_key_descriptor_set_plaintext(&shared_desc, point, sizeof(point));
// Re-init SE command context.
sl_status = sl_se_init_command_context(&cmd_ctx);
if (sl_status != SL_STATUS_OK)
{
return CHIP_ERROR_INTERNAL;
}
// Perform key agreement algorithm (ECDH).
sl_status = sl_se_ecdh_compute_shared_secret(&cmd_ctx, &priv_desc, &pub_desc, &shared_desc);
if (sl_status != SL_STATUS_OK)
{
ChipLogError(Crypto, "ECDH SL failure %lx", sl_status);
if (sl_status == SL_STATUS_COMMAND_IS_INVALID)
{
// This error will be returned if the key type isn't supported.
return CHIP_ERROR_NOT_IMPLEMENTED;
}
else
{
// If the ECDH operation failed, this is most likely due to the peer key
// being an invalid elliptic curve point. Other sources for failure should
// hopefully have been caught during parameter validation.
return CHIP_ERROR_INVALID_ARGUMENT;
}
}
}
status = mbedtls_mpi_read_binary(&((mbedtls_ecp_point *) R)->MBEDTLS_PRIVATE(X), point, kP256_FE_Length);
if (status != PSA_SUCCESS)
{
return CHIP_ERROR_INTERNAL;
}
status = mbedtls_mpi_read_binary(&((mbedtls_ecp_point *) R)->MBEDTLS_PRIVATE(Y), point + kP256_FE_Length, kP256_FE_Length);
if (status != PSA_SUCCESS)
{
return CHIP_ERROR_INTERNAL;
}
status = mbedtls_mpi_lset(&((mbedtls_ecp_point *) R)->MBEDTLS_PRIVATE(Z), 1);
if (status != PSA_SUCCESS)
{
return CHIP_ERROR_INTERNAL;
}
#else /* SEMAILBOX_PRESENT */
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;
}
#endif /* SEMAILBOX_PRESENT */
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 defined(SEMAILBOX_PRESENT)
CHIP_ERROR error = CHIP_NO_ERROR;
int result;
// Accelerate 'muladd' using separate point multiplication operations
mbedtls_ecp_point fe1P1, fe2P2;
mbedtls_mpi one;
mbedtls_mpi_init(&one);
mbedtls_ecp_point_init(&fe1P1);
mbedtls_ecp_point_init(&fe2P2);
result = mbedtls_mpi_lset(&one, 1);
VerifyOrExit(result == 0, error = CHIP_ERROR_NO_MEMORY);
// Do fe1P1 = fe1 * P1 and fe2P2 = fe2 * P2 since those can be accelerated
SuccessOrExit(error = PointMul(&fe1P1, P1, fe1));
SuccessOrExit(error = PointMul(&fe2P2, P2, fe2));
// Do R = (1 * fe1P1) + (1 * fe2P2) since point addition is not a public mbedTLS API
// mbedTLS will apply a shortcut since (1 * A) == A
result = mbedtls_ecp_muladd(&context->curve, (mbedtls_ecp_point *) R, &one, &fe1P1, &one, &fe2P2);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
exit:
mbedtls_mpi_free(&one);
mbedtls_ecp_point_free(&fe1P1);
mbedtls_ecp_point_free(&fe2P2);
return error;
#else /* SEMAILBOX_PRESENT */
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;
#endif /* SEMAILBOX_PRESENT */
}
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;
Spake2p_Context * context = to_inner_spake2p_context(&mSpake2pContext);
mbedtls_mpi w1_bn;
mbedtls_ecp_point Ltemp;
mbedtls_mpi_init(&w1_bn);
mbedtls_ecp_point_init(&Ltemp);
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, &context->curve.N);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
#if defined(SEMAILBOX_PRESENT)
// Do the point multiplication using hardware acceleration via ECDH primitive
error = PointMul(&Ltemp, &context->curve.G, &w1_bn);
if (error != CHIP_NO_ERROR)
{
goto exit;
}
#else /* SEMAILBOX_PRESENT */
result = mbedtls_ecp_mul(&context->curve, &Ltemp, &w1_bn, &context->curve.G, CryptoRNG, nullptr);
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
#endif /* SEMAILBOX_PRESENT */
memset(Lout, 0, *L_len);
result =
mbedtls_ecp_point_write_binary(&context->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);
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;
}
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 };
constexpr uint8_t sOID_Extension_CRLDistributionPoint[] = { 0x55, 0x1D, 0x1F };
/**
* 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))
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;
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)
{
unsigned char * seqStart = p;
result = mbedtls_asn1_get_bool(&p, end, &isCA);
VerifyOrExit(result == 0 || result == MBEDTLS_ERR_ASN1_UNEXPECTED_TAG, error = CHIP_ERROR_INTERNAL);
// Check if pathLen is there by validating if the cursor didn't get to the end of
// of the internal SEQUENCE for the basic constraints encapsulation.
// Missing pathLen optional tag will leave pathLen == -1 for following checks.
bool hasPathLen = (p != (seqStart + len));
if (hasPathLen)
{
// Extract pathLen value, making sure it's a valid format.
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
{
// For PAA, pathlen must be absent or equal to 1 (see Matter 1.1 spec 6.2.2.5)
VerifyOrExit(isCA && (pathLen == -1 || 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;
mbedtls_x509_time leaf_valid_from;
mbedtls_x509_crt * cert = NULL;
int mbedResult;
uint32_t flags;
int compare_from = 0;
int compare_until = 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));
leaf_valid_from = certChain.valid_from;
/* 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));
/* Validates that intermediate and root certificates are valid at the time of the leaf certificate's start time. */
compare_from = timeCompare(&leaf_valid_from, &rootCert.valid_from);
compare_until = timeCompare(&leaf_valid_from, &rootCert.valid_to);
VerifyOrExit((compare_from >= 0) && (compare_until <= 0),
(result = CertificateChainValidationResult::kChainInvalid, error = CHIP_ERROR_CERT_NOT_TRUSTED));
cert = certChain.next;
while (cert)
{
compare_from = timeCompare(&leaf_valid_from, &cert->valid_from);
compare_until = timeCompare(&leaf_valid_from, &cert->valid_to);
VerifyOrExit((compare_from >= 0) && (compare_until <= 0),
(result = CertificateChainValidationResult::kChainInvalid, error = CHIP_ERROR_CERT_NOT_TRUSTED));
cert = cert->next;
}
/* Verify the chain against the root */
mbedResult = mbedtls_x509_crt_verify(&certChain, &rootCert, NULL, NULL, &flags, NULL, NULL);
switch (mbedResult)
{
case 0:
VerifyOrExit(flags == 0, (result = CertificateChainValidationResult::kInternalFrameworkError, error = CHIP_ERROR_INTERNAL));
result = CertificateChainValidationResult::kSuccess;
break;
case MBEDTLS_ERR_X509_CERT_VERIFY_FAILED:
result = CertificateChainValidationResult::kChainInvalid;
error = CHIP_ERROR_CERT_NOT_TRUSTED;
break;
default:
result = CertificateChainValidationResult::kInternalFrameworkError;
error = CHIP_ERROR_INTERNAL;
break;
}
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;
}
inline 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 ByteSpan & referenceCertificate, const ByteSpan & toBeEvaluatedCertificate)
{
#if defined(MBEDTLS_X509_CRT_PARSE_C)
CHIP_ERROR error = CHIP_NO_ERROR;
mbedtls_x509_crt mbedReferenceCertificate;
mbedtls_x509_crt mbedToBeEvaluatedCertificate;
mbedtls_x509_time refNotBeforeTime;
mbedtls_x509_time tbeNotBeforeTime;
mbedtls_x509_time tbeNotAfterTime;
int result;
VerifyOrReturnError(!referenceCertificate.empty() && !toBeEvaluatedCertificate.empty(), CHIP_ERROR_INVALID_ARGUMENT);
mbedtls_x509_crt_init(&mbedReferenceCertificate);
mbedtls_x509_crt_init(&mbedToBeEvaluatedCertificate);
result = mbedtls_x509_crt_parse(&mbedReferenceCertificate, Uint8::to_const_uchar(referenceCertificate.data()),
referenceCertificate.size());
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
result = mbedtls_x509_crt_parse(&mbedToBeEvaluatedCertificate, Uint8::to_const_uchar(toBeEvaluatedCertificate.data()),
toBeEvaluatedCertificate.size());
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
refNotBeforeTime = mbedReferenceCertificate.CHIP_CRYPTO_PAL_PRIVATE_X509(valid_from);
tbeNotBeforeTime = mbedToBeEvaluatedCertificate.CHIP_CRYPTO_PAL_PRIVATE_X509(valid_from);
tbeNotAfterTime = mbedToBeEvaluatedCertificate.CHIP_CRYPTO_PAL_PRIVATE_X509(valid_to);
// check if referenceCertificate is issued at or after tbeCertificate's notBefore timestamp
VerifyOrExit(IsTimeGreaterThanEqual(&refNotBeforeTime, &tbeNotBeforeTime), error = CHIP_ERROR_CERT_EXPIRED);
// check if referenceCertificate is issued at or before tbeCertificate's notAfter timestamp
VerifyOrExit(IsTimeGreaterThanEqual(&tbeNotAfterTime, &refNotBeforeTime), error = CHIP_ERROR_CERT_EXPIRED);
exit:
_log_mbedTLS_error(result);
mbedtls_x509_crt_free(&mbedReferenceCertificate);
mbedtls_x509_crt_free(&mbedToBeEvaluatedCertificate);
#else
(void) referenceCertificate;
(void) toBeEvaluatedCertificate;
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 ExtractCRLDistributionPointURIFromX509Cert(const ByteSpan & certificate, MutableCharSpan & cdpurl)
{
#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;
size_t cdpExtCount = 0;
VerifyOrReturnError(!certificate.empty() && CanCastTo<long>(certificate.size()), CHIP_ERROR_INVALID_ARGUMENT);
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);
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 isCurrentExtCDP = OID_CMP(sOID_Extension_CRLDistributionPoint, 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);
unsigned char * end_of_ext = p + len;
if (isCurrentExtCDP)
{
// Only one CRL Distribution Point Extension is allowed.
cdpExtCount++;
VerifyOrExit(cdpExtCount <= 1, error = CHIP_ERROR_NOT_FOUND);
// CRL Distribution Point Extension is encoded as a sequence of DistributionPoint:
// CRLDistributionPoints ::= SEQUENCE SIZE (1..MAX) OF DistributionPoint
//
// This implementation only supports a single DistributionPoint (sequence of size 1),
// which is verified by comparing (p + len == end_of_ext)
result = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE);
VerifyOrExit(result == 0, error = CHIP_ERROR_NOT_FOUND);
VerifyOrExit(p + len == end_of_ext, error = CHIP_ERROR_NOT_FOUND);
// The DistributionPoint is a sequence of three optional elements:
// DistributionPoint ::= SEQUENCE {
// distributionPoint [0] DistributionPointName OPTIONAL,
// reasons [1] ReasonFlags OPTIONAL,
// cRLIssuer [2] GeneralNames OPTIONAL }
result = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE);
VerifyOrExit(result == 0, error = CHIP_ERROR_NOT_FOUND);
VerifyOrExit(p + len == end_of_ext, error = CHIP_ERROR_NOT_FOUND);
// The DistributionPointName is:
// DistributionPointName ::= CHOICE {
// fullName [0] GeneralNames,
// nameRelativeToCRLIssuer [1] RelativeDistinguishedName }
//
// The URI should be encoded in the fullName element.
result = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | 0);
VerifyOrExit(result == 0, error = CHIP_ERROR_NOT_FOUND);
// GeneralNames ::= SEQUENCE SIZE (1..MAX) OF GeneralName
result = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED);
VerifyOrExit(result == 0, error = CHIP_ERROR_NOT_FOUND);
unsigned char * end_of_general_names = p + len;
// The CDP URI is encoded as a uniformResourceIdentifier field of the GeneralName:
// GeneralName ::= CHOICE {
// otherName [0] OtherName,
// rfc822Name [1] IA5String,
// dNSName [2] IA5String,
// x400Address [3] ORAddress,
// directoryName [4] Name,
// ediPartyName [5] EDIPartyName,
// uniformResourceIdentifier [6] IA5String,
// iPAddress [7] OCTET STRING,
// registeredID [8] OBJECT IDENTIFIER }
result =
mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_X509_SAN_UNIFORM_RESOURCE_IDENTIFIER);
VerifyOrExit(result == 0, error = CHIP_ERROR_NOT_FOUND);
// Only single URI instance in the GeneralNames is supported
VerifyOrExit(p + len == end_of_general_names, error = CHIP_ERROR_NOT_FOUND);
const char * urlptr = reinterpret_cast<const char *>(p);
VerifyOrExit((len > strlen(kValidCDPURIHttpPrefix) &&
strncmp(urlptr, kValidCDPURIHttpPrefix, strlen(kValidCDPURIHttpPrefix)) == 0) ||
(len > strlen(kValidCDPURIHttpsPrefix) &&
strncmp(urlptr, kValidCDPURIHttpsPrefix, strlen(kValidCDPURIHttpsPrefix)) == 0),
error = CHIP_ERROR_NOT_FOUND);
error = CopyCharSpanToMutableCharSpan(CharSpan(urlptr, len), cdpurl);
SuccessOrExit(error);
}
p = end_of_ext;
}
VerifyOrExit(cdpExtCount == 1, error = CHIP_ERROR_NOT_FOUND);
exit:
_log_mbedTLS_error(result);
mbedtls_x509_crt_free(&mbed_cert);
#else
(void) certificate;
(void) cdpurl;
CHIP_ERROR error = CHIP_ERROR_NOT_IMPLEMENTED;
#endif // defined(MBEDTLS_X509_CRT_PARSE_C)
return error;
}
CHIP_ERROR ExtractCDPExtensionCRLIssuerFromX509Cert(const ByteSpan & certificate, MutableByteSpan & crlIssuer)
{
#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;
size_t cdpExtCount = 0;
VerifyOrReturnError(!certificate.empty() && CanCastTo<long>(certificate.size()), CHIP_ERROR_INVALID_ARGUMENT);
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);
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 isCurrentExtCDP = OID_CMP(sOID_Extension_CRLDistributionPoint, 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);
unsigned char * end_of_ext = p + len;
if (isCurrentExtCDP)
{
// Only one CRL Distribution Point Extension is allowed.
cdpExtCount++;
VerifyOrExit(cdpExtCount <= 1, error = CHIP_ERROR_NOT_FOUND);
// CRL Distribution Point Extension is encoded as a sequence of DistributionPoint:
// CRLDistributionPoints ::= SEQUENCE SIZE (1..MAX) OF DistributionPoint
//
// This implementation only supports a single DistributionPoint (sequence of size 1),
// which is verified by comparing (p + len == end_of_ext)
result = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE);
VerifyOrExit(result == 0, error = CHIP_ERROR_NOT_FOUND);
VerifyOrExit(p + len == end_of_ext, error = CHIP_ERROR_NOT_FOUND);
// The DistributionPoint is a sequence of three optional elements:
// DistributionPoint ::= SEQUENCE {
// distributionPoint [0] DistributionPointName OPTIONAL,
// reasons [1] ReasonFlags OPTIONAL,
// cRLIssuer [2] GeneralNames OPTIONAL }
result = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE);
VerifyOrExit(result == 0, error = CHIP_ERROR_NOT_FOUND);
VerifyOrExit(p + len == end_of_ext, error = CHIP_ERROR_NOT_FOUND);
// If distributionPoint element presents, ignore it
result = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | 0);
if (result == 0)
{
p += len;
VerifyOrExit(p < end_of_ext, error = CHIP_ERROR_NOT_FOUND);
}
// Check if cRLIssuer element present
result = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | 2);
VerifyOrExit(result == 0, error = CHIP_ERROR_NOT_FOUND);
// The CRL Issuer is encoded as a directoryName field of the GeneralName:
// GeneralName ::= CHOICE {
// otherName [0] OtherName,
// rfc822Name [1] IA5String,
// dNSName [2] IA5String,
// x400Address [3] ORAddress,
// directoryName [4] Name,
// ediPartyName [5] EDIPartyName,
// uniformResourceIdentifier [6] IA5String,
// iPAddress [7] OCTET STRING,
// registeredID [8] OBJECT IDENTIFIER }
result = mbedtls_asn1_get_tag(
&p, end, &len, MBEDTLS_ASN1_CONTEXT_SPECIFIC | MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_X509_SAN_DIRECTORY_NAME);
VerifyOrExit(result == 0, error = CHIP_ERROR_NOT_FOUND);
VerifyOrExit(p + len == end_of_ext, error = CHIP_ERROR_NOT_FOUND);
error = CopySpanToMutableSpan(ByteSpan(p, len), crlIssuer);
SuccessOrExit(error);
}
p = end_of_ext;
}
VerifyOrExit(cdpExtCount == 1, error = CHIP_ERROR_NOT_FOUND);
exit:
_log_mbedTLS_error(result);
mbedtls_x509_crt_free(&mbed_cert);
#else
(void) certificate;
(void) crlIssuer;
CHIP_ERROR error = CHIP_ERROR_NOT_IMPLEMENTED;
#endif // defined(MBEDTLS_X509_CRT_PARSE_C)
return error;
}
CHIP_ERROR ExtractSerialNumberFromX509Cert(const ByteSpan & certificate, MutableByteSpan & serialNumber)
{
#if defined(MBEDTLS_X509_CRT_PARSE_C)
CHIP_ERROR error = CHIP_NO_ERROR;
int result = 0;
uint8_t * p = nullptr;
size_t len = 0;
mbedtls_x509_crt mbed_cert;
mbedtls_x509_crt_init(&mbed_cert);
result = mbedtls_x509_crt_parse(&mbed_cert, Uint8::to_const_uchar(certificate.data()), certificate.size());
VerifyOrExit(result == 0, error = CHIP_ERROR_INTERNAL);
p = mbed_cert.CHIP_CRYPTO_PAL_PRIVATE_X509(serial).CHIP_CRYPTO_PAL_PRIVATE_X509(p);
len = mbed_cert.CHIP_CRYPTO_PAL_PRIVATE_X509(serial).CHIP_CRYPTO_PAL_PRIVATE_X509(len);
VerifyOrExit(len <= serialNumber.size(), error = CHIP_ERROR_BUFFER_TOO_SMALL);
memcpy(serialNumber.data(), p, len);
serialNumber.reduce_size(len);
exit:
_log_mbedTLS_error(result);
mbedtls_x509_crt_free(&mbed_cert);
#else
(void) certificate;
(void) serialNumber;
CHIP_ERROR error = CHIP_ERROR_NOT_IMPLEMENTED;
#endif // defined(MBEDTLS_X509_CRT_PARSE_C)
return error;
}
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 {
CHIP_ERROR ExtractRawDNFromX509Cert(bool extractSubject, const ByteSpan & certificate, MutableByteSpan & dn)
{
#if defined(MBEDTLS_X509_CRT_PARSE_C)
CHIP_ERROR error = CHIP_NO_ERROR;
int result = 0;
uint8_t * p = nullptr;
size_t len = 0;
mbedtls_x509_crt mbedCertificate;
ReturnErrorCodeIf(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);
if (extractSubject)
{
len = mbedCertificate.CHIP_CRYPTO_PAL_PRIVATE_X509(subject_raw).CHIP_CRYPTO_PAL_PRIVATE_X509(len);
p = mbedCertificate.CHIP_CRYPTO_PAL_PRIVATE_X509(subject_raw).CHIP_CRYPTO_PAL_PRIVATE_X509(p);
}
else
{
len = mbedCertificate.CHIP_CRYPTO_PAL_PRIVATE_X509(issuer_raw).CHIP_CRYPTO_PAL_PRIVATE_X509(len);
p = mbedCertificate.CHIP_CRYPTO_PAL_PRIVATE_X509(issuer_raw).CHIP_CRYPTO_PAL_PRIVATE_X509(p);
}
VerifyOrExit(len <= dn.size(), error = CHIP_ERROR_BUFFER_TOO_SMALL);
memcpy(dn.data(), p, len);
dn.reduce_size(len);
exit:
_log_mbedTLS_error(result);
mbedtls_x509_crt_free(&mbedCertificate);
#else
(void) certificate;
(void) dn;
CHIP_ERROR error = CHIP_ERROR_NOT_IMPLEMENTED;
#endif // defined(MBEDTLS_X509_CRT_PARSE_C)
return error;
}
} // namespace
CHIP_ERROR ExtractSubjectFromX509Cert(const ByteSpan & certificate, MutableByteSpan & subject)
{
return ExtractRawDNFromX509Cert(true, certificate, subject);
}
CHIP_ERROR ExtractIssuerFromX509Cert(const ByteSpan & certificate, MutableByteSpan & issuer)
{
return ExtractRawDNFromX509Cert(false, certificate, issuer);
}
CHIP_ERROR ReplaceCertIfResignedCertFound(const ByteSpan & referenceCertificate, const ByteSpan * candidateCertificates,
size_t candidateCertificatesCount, ByteSpan & outCertificate)
{
#if defined(MBEDTLS_X509_CRT_PARSE_C)
uint8_t referenceSubjectBuf[kMaxCertificateDistinguishedNameLength];
uint8_t referenceSKIDBuf[kSubjectKeyIdentifierLength];
MutableByteSpan referenceSubject(referenceSubjectBuf);
MutableByteSpan referenceSKID(referenceSKIDBuf);
outCertificate = referenceCertificate;
ReturnErrorCodeIf(candidateCertificates == nullptr || candidateCertificatesCount == 0, CHIP_NO_ERROR);
ReturnErrorOnFailure(ExtractSubjectFromX509Cert(referenceCertificate, referenceSubject));
ReturnErrorOnFailure(ExtractSKIDFromX509Cert(referenceCertificate, referenceSKID));
for (size_t i = 0; i < candidateCertificatesCount; i++)
{
const ByteSpan candidateCertificate = candidateCertificates[i];
uint8_t candidateSubjectBuf[kMaxCertificateDistinguishedNameLength];
uint8_t candidateSKIDBuf[kSubjectKeyIdentifierLength];
MutableByteSpan candidateSubject(candidateSubjectBuf);
MutableByteSpan candidateSKID(candidateSKIDBuf);
ReturnErrorOnFailure(ExtractSubjectFromX509Cert(candidateCertificate, candidateSubject));
ReturnErrorOnFailure(ExtractSKIDFromX509Cert(candidateCertificate, candidateSKID));
if (referenceSKID.data_equal(candidateSKID) && referenceSubject.data_equal(candidateSubject))
{
outCertificate = candidateCertificate;
return CHIP_NO_ERROR;
}
}
return CHIP_NO_ERROR;
#else
(void) referenceCertificate;
(void) candidateCertificates;
(void) candidateCertificatesCount;
(void) outCertificate;
return CHIP_ERROR_NOT_IMPLEMENTED;
#endif // defined(MBEDTLS_X509_CRT_PARSE_C)
}
} // namespace Crypto
} // namespace chip