int com_mac_block_compute_impl(char* arg, int update) {
char* block_str = strtok(arg, " ");
if (!block_str) {
printf("Too few arguments: #block\n");
return -1;
}
unsigned int block = (unsigned int) strtoul(block_str, &block_str, 16);
if (*block_str != '\0') {
printf("Invalid block character (non hex): %s\n", block_str);
return -1;
}
if (block < 0 || block > 0xff) {
printf("Invalid block [0,ff]: %x\n", block);
return -1;
}
// Use the key
unsigned char* mac = compute_block_mac(block, current_mac_key, update);
// MAC is null on error, else 8 bytes
if (mac == 0)
return -1;
// Only need 16 MSBs.
printf("Block %2.2x, MAC : ", block);
print_hex_array_sep(mac, 2, " ");
printf("\n");
return 0;
}
int com_mac_validate(char* arg) {
char* a = strtok(arg, " ");
if (a && strtok(NULL, " ") != (char*)NULL) {
printf("Too many arguments\n");
return -1;
}
mf_size_t size = parse_size_default(a, MF_1K);
if (size == MF_INVALID_SIZE) {
printf("Unknown argument: %s\n", a);
return -1;
}
for(size_t i = 1; i < block_count(size); i++)
{
if(is_trailer_block(i))
{
continue;
}
unsigned char* mac = compute_block_mac(i, current_mac_key, 0);
printf("Block: %2x ", i);
printf("Tag: ");
print_hex_array_sep(¤t_tag.amb[i].mbd.abtData[14], 2, " ");
printf(" Computed: ");
print_hex_array_sep(mac, 2, " ");
printf(" Result: ");
if(memcmp(mac, ¤t_tag.amb[i].mbd.abtData[14], 2) == 0)
{
printf("VALID");
} else {
printf("IN-VALID");
}
printf("\n");
}
return 0;
}
int com_mac_key_get_set(char* arg) {
char* key_str = strtok(arg, " ");
if (key_str == 0) {
printf("Current MAC key: \n");
print_hex_array_sep(current_mac_key, 8, " ");
printf("\n");
return 0;
}
uint8_t key[8];
int key_ptr = 0;
// Consume the key tokens
do {
long int byte = strtol(key_str, &key_str, 16);
if (*key_str != '\0') {
printf("Invalid key character (non hex): %s\n", key_str);
return -1;
}
if (byte < 0 || byte > 0xff) {
printf("Invalid byte value [0,ff]: %lx\n", byte);
return -1;
}
if (key_ptr > sizeof(key)) {
printf("Too many bytes specified in key (should be 8).\n");
return -1;
}
// Accept the byte and add it to the key
key[key_ptr++] = (uint8_t)byte;
} while((key_str = strtok(NULL, " ")) != (char*)NULL);
if (key_ptr != sizeof(key)) {
printf("Too few bytes specified in key (should be 8).\n");
return -1;
}
// Everything ok, so update the global
memcpy(current_mac_key, key, 8);
return 0;
}
void print_hex_array(const unsigned char* data, size_t nbytes) {
print_hex_array_sep(data, nbytes, NULL);
}
