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esphome/esphome/components/hmac_sha256/hmac_sha256.cpp

100 lines
2.9 KiB
C++

#include <cstring>
#include "hmac_sha256.h"
#if defined(USE_ESP32) || defined(USE_ESP8266) || defined(USE_RP2040) || defined(USE_LIBRETINY) || defined(USE_HOST)
#include "esphome/core/helpers.h"
namespace esphome::hmac_sha256 {
constexpr size_t SHA256_DIGEST_SIZE = 32;
#if defined(USE_ESP32) || defined(USE_LIBRETINY)
HmacSHA256::~HmacSHA256() { mbedtls_md_free(&this->ctx_); }
void HmacSHA256::init(const uint8_t *key, size_t len) {
mbedtls_md_init(&this->ctx_);
const mbedtls_md_info_t *md_info = mbedtls_md_info_from_type(MBEDTLS_MD_SHA256);
mbedtls_md_setup(&this->ctx_, md_info, 1); // 1 = HMAC mode
mbedtls_md_hmac_starts(&this->ctx_, key, len);
}
void HmacSHA256::add(const uint8_t *data, size_t len) { mbedtls_md_hmac_update(&this->ctx_, data, len); }
void HmacSHA256::calculate() { mbedtls_md_hmac_finish(&this->ctx_, this->digest_); }
void HmacSHA256::get_bytes(uint8_t *output) { memcpy(output, this->digest_, SHA256_DIGEST_SIZE); }
void HmacSHA256::get_hex(char *output) {
format_hex_to(output, SHA256_DIGEST_SIZE * 2 + 1, this->digest_, SHA256_DIGEST_SIZE);
}
bool HmacSHA256::equals_bytes(const uint8_t *expected) {
return memcmp(this->digest_, expected, SHA256_DIGEST_SIZE) == 0;
}
bool HmacSHA256::equals_hex(const char *expected) {
char hex_output[SHA256_DIGEST_SIZE * 2 + 1];
this->get_hex(hex_output);
hex_output[SHA256_DIGEST_SIZE * 2] = '\0';
return strncmp(hex_output, expected, SHA256_DIGEST_SIZE * 2) == 0;
}
#else
HmacSHA256::~HmacSHA256() = default;
// HMAC block size for SHA256 (RFC 2104)
constexpr size_t HMAC_BLOCK_SIZE = 64;
void HmacSHA256::init(const uint8_t *key, size_t len) {
uint8_t ipad[HMAC_BLOCK_SIZE], opad[HMAC_BLOCK_SIZE];
memset(ipad, 0, sizeof(ipad));
if (len > HMAC_BLOCK_SIZE) {
sha256::SHA256 keysha256;
keysha256.init();
keysha256.add(key, len);
keysha256.calculate();
keysha256.get_bytes(ipad);
} else {
memcpy(ipad, key, len);
}
memcpy(opad, ipad, sizeof(opad));
for (size_t i = 0; i < HMAC_BLOCK_SIZE; i++) {
ipad[i] ^= 0x36;
opad[i] ^= 0x5c;
}
this->ihash_.init();
this->ihash_.add(ipad, sizeof(ipad));
this->ohash_.init();
this->ohash_.add(opad, sizeof(opad));
}
void HmacSHA256::add(const uint8_t *data, size_t len) { this->ihash_.add(data, len); }
void HmacSHA256::calculate() {
uint8_t ibytes[32];
this->ihash_.calculate();
this->ihash_.get_bytes(ibytes);
this->ohash_.add(ibytes, sizeof(ibytes));
this->ohash_.calculate();
}
void HmacSHA256::get_bytes(uint8_t *output) { this->ohash_.get_bytes(output); }
void HmacSHA256::get_hex(char *output) { this->ohash_.get_hex(output); }
bool HmacSHA256::equals_bytes(const uint8_t *expected) { return this->ohash_.equals_bytes(expected); }
bool HmacSHA256::equals_hex(const char *expected) { return this->ohash_.equals_hex(expected); }
#endif // USE_ESP32 || USE_LIBRETINY
} // namespace esphome::hmac_sha256
#endif