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#include "Utils.h"
#include <AES.h>
#include <SHA256.h>
#ifdef ARDUINO
#include <Arduino.h>
#endif
namespace mesh {
extern "C" void MeshCoreWatchdogStage(uint8_t stage) __attribute__((weak));
namespace {
#ifdef AVR_PLATFORM
typedef AESSmall128 MeshAES128;
#else
typedef AES128 MeshAES128;
#endif
void watchdogStage(uint8_t stage) {
if (MeshCoreWatchdogStage) {
MeshCoreWatchdogStage(stage);
}
}
}
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) {
SHA256 sha;
if (msg && msg_len > 0) {
sha.update(msg, (size_t)msg_len);
}
sha.finalize(hash, hash_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) {
SHA256 sha;
if (frag1 && frag1_len > 0) {
sha.update(frag1, (size_t)frag1_len);
}
if (frag2 && frag2_len > 0) {
sha.update(frag2, (size_t)frag2_len);
}
sha.finalize(hash, hash_len);
}
int Utils::decrypt(const uint8_t* shared_secret, uint8_t* dest, const uint8_t* src, int src_len) {
if (src_len <= 0 || (src_len % CIPHER_BLOCK_SIZE) != 0 || src_len > MAX_PACKET_PAYLOAD) {
return 0;
}
MeshAES128 aes;
uint8_t* dp = dest;
const uint8_t* sp = src;
uint8_t block = 0;
watchdogStage('k');
aes.setKey(shared_secret, CIPHER_KEY_SIZE);
while (sp - src < src_len) {
watchdogStage((uint8_t)('0' + block));
aes.decryptBlock(dp, sp);
dp += 16; sp += 16;
if (block < 9) {
++block;
}
}
watchdogStage('d');
return sp - src; // will always be multiple of 16
}
int Utils::encrypt(const uint8_t* shared_secret, uint8_t* dest, const uint8_t* src, int src_len) {
if (src_len < 0 || src_len > MAX_PACKET_PAYLOAD) {
return 0;
}
int enc_len = ((src_len + CIPHER_BLOCK_SIZE - 1) / CIPHER_BLOCK_SIZE) * CIPHER_BLOCK_SIZE;
if (enc_len > MAX_PACKET_PAYLOAD) {
return 0;
}
MeshAES128 aes;
uint8_t* dp = dest;
watchdogStage('K');
aes.setKey(shared_secret, CIPHER_KEY_SIZE);
while (src_len >= 16) {
watchdogStage('E');
aes.encryptBlock(dp, src);
dp += 16; src += 16; src_len -= 16;
}
if (src_len > 0) { // remaining partial block
uint8_t tmp[16];
memset(tmp, 0, 16);
memcpy(tmp, src, src_len);
watchdogStage('e');
aes.encryptBlock(dp, tmp);
dp += 16;
}
return dp - dest; // will always be multiple of 16
}
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);
SHA256 sha;
sha.resetHMAC(shared_secret, PUB_KEY_SIZE);
sha.update(dest + CIPHER_MAC_SIZE, enc_len);
sha.finalizeHMAC(shared_secret, PUB_KEY_SIZE, dest, CIPHER_MAC_SIZE);
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 (src_len <= CIPHER_MAC_SIZE) return 0; // invalid src bytes
int cipher_len = src_len - CIPHER_MAC_SIZE;
if ((cipher_len % CIPHER_BLOCK_SIZE) != 0 || cipher_len > MAX_PACKET_PAYLOAD) {
return 0;
}
uint8_t hmac[CIPHER_MAC_SIZE];
{
watchdogStage('h');
SHA256 sha;
sha.resetHMAC(shared_secret, PUB_KEY_SIZE);
sha.update(src + CIPHER_MAC_SIZE, cipher_len);
sha.finalizeHMAC(shared_secret, PUB_KEY_SIZE, hmac, CIPHER_MAC_SIZE);
}
if (memcmp(hmac, src, CIPHER_MAC_SIZE) == 0) {
watchdogStage('a');
return decrypt(shared_secret, dest, src + CIPHER_MAC_SIZE, cipher_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) {
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++;
*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;
}
}
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