Files
HaloKeymind/src/Utils.cpp
T

301 lines
9.4 KiB
C++

#include "Utils.h"
#include <AES.h>
#include <SHA256.h>
#ifdef USE_CC310_HW_CRYPTO
#include "helpers/NRF52Crypto.h"
#include "nrf_cc310/include/crys_hash.h"
#include "nrf_cc310/include/crys_hmac.h"
#include "nrf_cc310/include/ssi_aes.h"
#endif
#ifdef ARDUINO
#include <Arduino.h>
#endif
namespace {
void sha256Software(uint8_t* hash, size_t hash_len, const uint8_t* msg, int msg_len) {
SHA256 sha;
sha.update(msg, msg_len);
sha.finalize(hash, hash_len);
}
void sha256Software(uint8_t* hash, size_t hash_len,
const uint8_t* frag1, int frag1_len,
const uint8_t* frag2, int frag2_len) {
SHA256 sha;
sha.update(frag1, frag1_len);
sha.update(frag2, frag2_len);
sha.finalize(hash, hash_len);
}
int decryptSoftware(const uint8_t* shared_secret, uint8_t* dest,
const uint8_t* src, int src_len) {
AES128 aes;
uint8_t* dp = dest;
const uint8_t* sp = src;
aes.setKey(shared_secret, CIPHER_KEY_SIZE);
while (sp - src < src_len) {
aes.decryptBlock(dp, sp);
dp += CIPHER_BLOCK_SIZE;
sp += CIPHER_BLOCK_SIZE;
}
return static_cast<int>(sp - src);
}
int encryptSoftware(const uint8_t* shared_secret, uint8_t* dest,
const uint8_t* src, int src_len) {
AES128 aes;
uint8_t* dp = dest;
aes.setKey(shared_secret, CIPHER_KEY_SIZE);
while (src_len >= CIPHER_BLOCK_SIZE) {
aes.encryptBlock(dp, src);
dp += CIPHER_BLOCK_SIZE;
src += CIPHER_BLOCK_SIZE;
src_len -= CIPHER_BLOCK_SIZE;
}
if (src_len > 0) {
uint8_t tmp[CIPHER_BLOCK_SIZE] = {};
memcpy(tmp, src, src_len);
aes.encryptBlock(dp, tmp);
dp += CIPHER_BLOCK_SIZE;
}
return static_cast<int>(dp - dest);
}
void hmacSoftware(const uint8_t* shared_secret, uint8_t* dest,
const uint8_t* src, int src_len) {
SHA256 sha;
sha.resetHMAC(shared_secret, PUB_KEY_SIZE);
sha.update(src, src_len);
sha.finalizeHMAC(shared_secret, PUB_KEY_SIZE, dest, CIPHER_MAC_SIZE);
}
#ifdef USE_CC310_HW_CRYPTO
bool rangesOverlap(const uint8_t* first, size_t first_len,
const uint8_t* second, size_t second_len) {
const uintptr_t first_addr = reinterpret_cast<uintptr_t>(first);
const uintptr_t second_addr = reinterpret_cast<uintptr_t>(second);
if (first_addr <= second_addr) return second_addr - first_addr < first_len;
return first_addr - second_addr < second_len;
}
// Returns -1 when the hardware path is unavailable or any CC310 call fails.
// Callers retain the original input and can recompute the complete result in
// software.
int aesHardware(bool encrypting, const uint8_t* shared_secret, uint8_t* dest,
const uint8_t* src, int src_len) {
mesh::CC310CryptoSession session;
if (!session) return -1;
static SaSiAesUserContext_t ctx;
SaSiAesUserKeyData_t key_data = {
const_cast<uint8_t*>(shared_secret), CIPHER_KEY_SIZE
};
SaSiError_t rc = SaSi_AesInit(
&ctx, encrypting ? SASI_AES_ENCRYPT : SASI_AES_DECRYPT,
SASI_AES_MODE_ECB, SASI_AES_PADDING_NONE);
const bool initialized = rc == SASI_OK;
if (rc == SASI_OK) {
rc = SaSi_AesSetKey(&ctx, SASI_AES_USER_KEY, &key_data, sizeof(key_data));
}
uint8_t* dp = dest;
const uint8_t* sp = src;
int remaining = src_len;
while (rc == SASI_OK && remaining >= CIPHER_BLOCK_SIZE) {
rc = SaSi_AesBlock(&ctx, const_cast<uint8_t*>(sp), CIPHER_BLOCK_SIZE, dp);
if (rc == SASI_OK) {
dp += CIPHER_BLOCK_SIZE;
sp += CIPHER_BLOCK_SIZE;
remaining -= CIPHER_BLOCK_SIZE;
}
}
if (rc == SASI_OK && encrypting && remaining > 0) {
uint8_t padded[CIPHER_BLOCK_SIZE] = {};
memcpy(padded, sp, remaining);
rc = SaSi_AesBlock(&ctx, padded, CIPHER_BLOCK_SIZE, dp);
if (rc == SASI_OK) dp += CIPHER_BLOCK_SIZE;
}
size_t final_size = 0;
if (rc == SASI_OK) {
rc = SaSi_AesFinish(&ctx, 0, NULL, 0, NULL, &final_size);
}
const SaSiError_t free_rc = initialized ? SaSi_AesFree(&ctx) : SASI_OK;
if (rc != SASI_OK || free_rc != SASI_OK) return -1;
return static_cast<int>(dp - dest);
}
bool hmacHardware(const uint8_t* shared_secret, uint8_t* dest,
const uint8_t* src, int src_len) {
mesh::CC310CryptoSession session;
if (!session) return false;
static CRYS_HASH_Result_t result;
const CRYSError_t rc = CRYS_HMAC(
CRYS_HASH_SHA256_mode, const_cast<uint8_t*>(shared_secret), PUB_KEY_SIZE,
const_cast<uint8_t*>(src), static_cast<size_t>(src_len), result);
if (rc != CRYS_OK) return false;
memcpy(dest, result, CIPHER_MAC_SIZE);
return true;
}
#endif
} // namespace
namespace mesh {
uint32_t RNG::nextInt(uint32_t _min, uint32_t _max) {
uint32_t num;
random((uint8_t *) &num, sizeof(num));
return (num % (_max - _min)) + _min;
}
void Utils::sha256(uint8_t *hash, size_t hash_len, const uint8_t* msg, int msg_len) {
// CC310 can report CRYS_OK yet return a wrong digest when the input is the
// memory-mapped nRF52 application image. SHA-256 protects firmware identity,
// Merkle proofs, and install gates, so a return-code fallback is insufficient:
// always use the deterministic software implementation. CC310 remains in use
// for AES, HMAC, and entropy, where its inputs live in ordinary RAM.
sha256Software(hash, hash_len, msg, msg_len);
}
void Utils::sha256(uint8_t *hash, size_t hash_len, const uint8_t* frag1, int frag1_len, const uint8_t* frag2, int frag2_len) {
sha256Software(hash, hash_len, frag1, frag1_len, frag2, frag2_len);
}
int Utils::decrypt(const uint8_t* shared_secret, uint8_t* dest, const uint8_t* src, int src_len) {
if (shared_secret == NULL || dest == NULL || src == NULL || src_len <= 0
|| (src_len % CIPHER_BLOCK_SIZE) != 0) {
return 0;
}
#ifdef USE_CC310_HW_CRYPTO
if (!rangesOverlap(dest, static_cast<size_t>(src_len),
src, static_cast<size_t>(src_len))) {
const int hardware_len = aesHardware(false, shared_secret, dest, src, src_len);
if (hardware_len >= 0) return hardware_len;
}
#endif
return decryptSoftware(shared_secret, dest, src, src_len);
}
int Utils::encrypt(const uint8_t* shared_secret, uint8_t* dest, const uint8_t* src, int src_len) {
if (shared_secret == NULL || dest == NULL || src == NULL || src_len <= 0) return 0;
#ifdef USE_CC310_HW_CRYPTO
const size_t output_len = static_cast<size_t>(
(src_len + CIPHER_BLOCK_SIZE - 1) / CIPHER_BLOCK_SIZE * CIPHER_BLOCK_SIZE);
if (!rangesOverlap(dest, output_len, src, static_cast<size_t>(src_len))) {
const int hardware_len = aesHardware(true, shared_secret, dest, src, src_len);
if (hardware_len >= 0) return hardware_len;
}
#endif
return encryptSoftware(shared_secret, dest, src, src_len);
}
int Utils::encryptThenMAC(const uint8_t* shared_secret, uint8_t* dest, const uint8_t* src, int src_len) {
int enc_len = encrypt(shared_secret, dest + CIPHER_MAC_SIZE, src, src_len);
#ifdef USE_CC310_HW_CRYPTO
if (!hmacHardware(shared_secret, dest, dest + CIPHER_MAC_SIZE, enc_len))
#endif
{
hmacSoftware(shared_secret, dest, dest + CIPHER_MAC_SIZE, enc_len);
}
return CIPHER_MAC_SIZE + enc_len;
}
int Utils::MACThenDecrypt(const uint8_t* shared_secret, uint8_t* dest, const uint8_t* src, int src_len) {
if (shared_secret == NULL || dest == NULL || src == NULL || src_len <= CIPHER_MAC_SIZE) return 0;
const int enc_len = src_len - CIPHER_MAC_SIZE;
if ((enc_len % CIPHER_BLOCK_SIZE) != 0) return 0; // reject partial AES blocks before hashing/decrypting
uint8_t hmac[CIPHER_MAC_SIZE];
#ifdef USE_CC310_HW_CRYPTO
if (!hmacHardware(shared_secret, hmac, src + CIPHER_MAC_SIZE, enc_len))
#endif
{
hmacSoftware(shared_secret, hmac, src + CIPHER_MAC_SIZE, enc_len);
}
if (memcmp(hmac, src, CIPHER_MAC_SIZE) == 0) {
return decrypt(shared_secret, dest, src + CIPHER_MAC_SIZE, enc_len);
}
return 0; // invalid HMAC
}
static const char hex_chars[] = "0123456789ABCDEF";
void Utils::toHex(char* dest, const uint8_t* src, size_t len) {
while (len > 0) {
uint8_t b = *src++;
*dest++ = hex_chars[b >> 4];
*dest++ = hex_chars[b & 0x0F];
len--;
}
*dest = 0;
}
void Utils::printHex(Stream& s, const uint8_t* src, size_t len) {
while (len > 0) {
uint8_t b = *src++;
s.print(hex_chars[b >> 4]);
s.print(hex_chars[b & 0x0F]);
len--;
}
}
static uint8_t hexVal(char c) {
if (c >= 'A' && c <= 'F') return c - 'A' + 10;
if (c >= 'a' && c <= 'f') return c - 'a' + 10;
if (c >= '0' && c <= '9') return c - '0';
return 0;
}
bool Utils::isHexChar(char c) {
return c == '0' || hexVal(c) > 0;
}
bool Utils::fromHex(uint8_t* dest, int dest_size, const char *src_hex) {
if (dest == NULL || src_hex == NULL || dest_size < 0) return false;
int len = strlen(src_hex);
if (len != dest_size*2) return false; // incorrect length
uint8_t* dp = dest;
while (dp - dest < dest_size) {
char ch = *src_hex++;
char cl = *src_hex++;
if (!isHexChar(ch) || !isHexChar(cl)) return false;
*dp++ = (hexVal(ch) << 4) | hexVal(cl);
}
return true;
}
int Utils::parseTextParts(char* text, const char* parts[], int max_num, char separator) {
int num = 0;
char* sp = text;
while (*sp && num < max_num) {
parts[num++] = sp;
while (*sp && *sp != separator) sp++;
if (*sp) {
*sp++ = 0; // replace the seperator with a null, and skip past it
}
}
// if we hit the maximum parts, make sure LAST entry does NOT have separator
while (*sp && *sp != separator) sp++;
if (*sp) {
*sp = 0; // replace the separator with null
}
return num;
}
}