uint8_t aes_decr(const void* in, void* out, uint32_t length, uint8_t mac_len)
{
/* verify parameters */
if(mac_len>AES_BLOCK_SIZE)
return 1;
if(length<=mac_len)
return 2;
/* calculate payload length */
length -= mac_len;
/* re-create IV from end of packet */
memcpy(&g_encrypt.in, ((uint8_t*)in) + length, mac_len);
/* pad IV with 0xFF if needed to generate IV block */
if(mac_len<AES_BLOCK_SIZE)
memset(&g_encrypt.in[mac_len], 0xFF, AES_BLOCK_SIZE-mac_len);
/* decrypt data */
aes_process((uint8_t*)in, (uint8_t*)out, length);
/* verify signature */
if(memcmp(aes_sign(out, length), ((uint8_t*)in) + length, mac_len)==0)
{
/* reset signature in output */
memset(((uint8_t*)out) + length, 0xFF, mac_len);
return 0;
}
else
{
/* erase broken payload */
memset(out, 0, length);
return 3;
}
}
s8t processIncomingMsg_USM(u8t* const input, const u16t input_len, u16t* pos, message_v3_t* request)
{
/* If the value of the msgAuthoritativeEngineID field in the securityParameters is unknown, return usmStatsUnknownEngineIDs */
TRY(decode_USM_parameters(input, input_len, pos, request));
if (request->msgAuthoritativeEngineID.len != getEngineID()->len ||
memcmp(request->msgAuthoritativeEngineID.ptr, getEngineID()->ptr, getEngineID()->len)) {
TRY(report(request, &usmStatsUnknownEngineIDs, &usmStatsUnknownEngineIDCounter));
return ERR_USM;
}
/* check user name */
if (request->msgUserName.len != strlen((char*)getUserName()) || memcmp(request->msgUserName.ptr, getUserName(), request->msgUserName.len) != 0) {
TRY(report(request, &usmStatsUnknownUserNames, &usmStatsUnknownUserNamesCounter));
return ERR_USM;
}
if (request->msgFlags & FLAG_AUTH) {
#if ENABLE_AUTH
/* The timeliness check is only performed if authentication is applied to the message */
if (request->msgAuthenticationParameters.len != 12 || isBadHMAC(input, input_len, request) != ERR_NO_ERROR) {
TRY(report(request, &usmStatsWrongDigests, &usmStatsWrongDigestsCounter));
return ERR_USM;
}
#else
return FAILURE;
#endif
}
if (request->msgAuthoritativeEngineBoots != getMsgAuthoritativeEngineBoots() ||
abs(request->msgAuthoritativeEngineTime - getSysUpTime()) < TIME_WINDOW) {
TRY(report(request, &usmStatsNotInTimeWindows, &usmStatsNotInTimeWindowsCounter));
return ERR_USM;
}
if (request->msgFlags & FLAG_PRIV) {
#if ENABLE_PRIVACY
if (request->msgPrivacyParameters.len != 8) {
TRY(report(request, &usmStatsDecryptionErrors, &usmStatsDecryptionErrorsCounter));
return ERR_USM;
}
/* init IV */
u8t iv[16];
convert_2_octets(iv, request->msgAuthoritativeEngineBoots);
convert_2_octets(iv + 4, request->msgAuthoritativeEngineTime);
memcpy(iv + 8, request->msgPrivacyParameters.ptr, 8);
/* decode the Scoped PDU */
aes_process(getPrivKul(), iv, input + *pos, input + *pos, input_len - *pos, AES_DECRYPT);
#else
return FAILURE;
#endif
}
return 0;
}
// One-time setup on factory install
void memory_setup(void)
{
if (memory_read_setup()) {
memory_erase();
#ifndef TESTING
// Lock Config Memory: OP MODE PARAMETER1 PARAMETER2
const uint8_t ataes_cmd[] = {0x0D, 0x02, 0x00, 0x00, 0x00, 0x00};
// Return packet [Count(1) || Return Code (1) || CRC (2)]
uint8_t ataes_ret[4] = {0};
aes_process(ataes_cmd, sizeof(ataes_cmd), ataes_ret, 4);
#endif
memory_write_setup(0x00);
} else {
memory_mempass();
}
}
uint8_t aes_encr(const void* in, void* out, uint32_t length, uint8_t mac_len)
{
/* verify parameters */
if(mac_len>AES_BLOCK_SIZE)
return 1;
if(length<=mac_len)
return 2;
/* calculate payload length */
length -= mac_len;
/* sign payload to create IV */
memcpy(&g_encrypt.in, aes_sign(in, length), mac_len);
/* pad IV with 0xFF if needed to generate IV block */
if(mac_len<AES_BLOCK_SIZE)
memset(&g_encrypt.in[mac_len], 0xFF, AES_BLOCK_SIZE-mac_len);
/* copy IV to payload end */
memcpy((uint8_t*)out + length, &g_encrypt.in, mac_len);
/* encrypt data */
aes_process((uint8_t*)in, (uint8_t*)out, length);
return 0;
}
static s8t encode_USM_parameters(message_v3_t* message, u8t* output, u16t buf_len, s16t* pos) {
if (message->msgFlags & FLAG_PRIV) {
#if ENABLE_PRIVACY
u8t iv[16];
/* IV */
convert_2_octets(iv, message->msgAuthoritativeEngineBoots);
convert_2_octets(iv + 4, message->msgAuthoritativeEngineTime);
/* privace parameters */
convert_2_octets(message->msgPrivacyParameters.ptr, getLPrivacyParameters());
convert_2_octets(message->msgPrivacyParameters.ptr, getHPrivacyParameters());
memcpy(iv + 8, message->msgPrivacyParameters.ptr, 8);
aes_process(getPrivKul(), iv, output + *pos, output + *pos, buf_len - *pos, AES_ENCRYPT);
TRY(ber_encode_type_length(output, pos, BER_TYPE_OCTET_STRING, buf_len - *pos));
#else
return FAILURE;
#endif
}
s16t tmpPos = *pos;
TRY(ber_encode_fixed_string(output, pos, message->msgPrivacyParameters.ptr, message->msgPrivacyParameters.len));
TRY(ber_encode_fixed_string(output, pos, message->msgAuthenticationParameters.ptr, message->msgAuthenticationParameters.len));
message->msgAuthenticationParameters.ptr = &output[*pos + 2];
TRY(ber_encode_fixed_string(output, pos, message->msgUserName.ptr, message->msgUserName.len));
TRY(ber_encode_integer(output, pos, BER_TYPE_INTEGER, message->msgAuthoritativeEngineTime));
TRY(ber_encode_integer(output, pos, BER_TYPE_INTEGER, message->msgAuthoritativeEngineBoots));
TRY(ber_encode_fixed_string(output, pos, message->msgAuthoritativeEngineID.ptr, message->msgAuthoritativeEngineID.len));
TRY(ber_encode_type_length(output, pos, BER_TYPE_SEQUENCE, tmpPos - *pos));
TRY(ber_encode_type_length(output, pos, BER_TYPE_OCTET_STRING, tmpPos - *pos));
return 0;
}
s8t processIncomingMsg_USM(u8t* const input, const u16t input_len, u16t* pos, message_v3_t* request)
{
/* If the value of the msgAuthoritativeEngineID field in the securityParameters is unknown, return usmStatsUnknownEngineIDs */
TRY(decode_USM_parameters(input, input_len, pos, request));
if (request->msgAuthoritativeEngineID.len != getEngineID()->len ||
memcmp(request->msgAuthoritativeEngineID.ptr, getEngineID()->ptr, getEngineID()->len)) {
TRY(report(request, &usmStatsUnknownEngineIDs, &usmStatsUnknownEngineIDCounter));
#if PDEBUG
printf("USM Modul: Error! Wrong Engine ID!\n");
#endif
return ERR_USM;
}
/* check user name */
if (request->msgUserName.len != strlen((char*)getUserName()) || memcmp(request->msgUserName.ptr, getUserName(), request->msgUserName.len) != 0) {
TRY(report(request, &usmStatsUnknownUserNames, &usmStatsUnknownUserNamesCounter));
#if PDEBUG
printf("USM Modul: Error! Wrong Username\n");
#endif
return ERR_USM;
}
/*sz*/
#if ENABLE_AUTH
if (!(request->msgFlags & FLAG_AUTH))
{
#if PDEBUG
printf("USM Modul: Error! User needs Authentication\n");
#endif
TRY(report(request, &usmStatsUnsupportedSecurityLevel, &usmStatsUnsupportedSecurityLevelCounter));
return ERR_USM;
}
#endif
/*sz*/
if (request->msgFlags & FLAG_AUTH) {
#if ENABLE_AUTH
/* The timeliness check is only performed if authentication is applied to the message */
if (request->msgAuthenticationParameters.len != 12 || isBadHMAC(input, input_len, request) != ERR_NO_ERROR) {
#ifndef DISABLE_HMAC
TRY(report(request, &usmStatsWrongDigests, &usmStatsWrongDigestsCounter));
#if PDEBUG
printf("USM Modul: Error! Authentication Failed!\n");
#endif
return ERR_USM;
#endif /* Disable HMAC */
}
#else
return FAILURE;
#endif
}
#if ENABLE_AUTH /*sz*/
#if PDEBUG
printf("Checking Engine Time getsysuptime()/100: %d\n",(getSysUpTime()/100));
printf("Request EngineTime:%d\n", request->msgAuthoritativeEngineTime);
printf("RequestTime - getSysUpTime/100: %d \n", (request->msgAuthoritativeEngineTime - (getSysUpTime()/100)));
printf("abs of RequestTime - getSysUpTime/100: %d \n",(abs(request->msgAuthoritativeEngineTime - (getSysUpTime()/100))));
printf("Checking if it is in the time window (1 if it is not!!!) %d\n", (abs(request->msgAuthoritativeEngineTime - (getSysUpTime()/100)) > TIME_WINDOW));
if (request->msgAuthoritativeEngineBoots == 0){
printf("USM Modul: request->msgAuthoritativeEngineBoots == 0\n");
}
if (request->msgAuthoritativeEngineBoots != getMsgAuthoritativeEngineBoots()){
printf("USM Modul: request->msgAuthoritativeEngineBoots != getMsgAuthoritativeEngineBoots()\n");
}
if (abs(request->msgAuthoritativeEngineTime - getSysUpTime()) < TIME_WINDOW){
printf("USM Modul: abs(request->msgAuthoritativeEngineTime - getSysUpTime()) < TIME_WINDOW\n");
}
if (getMsgAuthoritativeEngineBoots()>=2147483647){
printf("USM Modul: getMsgAuthoritativeEngineBoots()>=2147483647\n");
}
#endif
#if DISABLE_MAET == 0
if (request->msgAuthoritativeEngineBoots != getMsgAuthoritativeEngineBoots() ||
abs(request->msgAuthoritativeEngineTime - (getSysUpTime()/100)) > TIME_WINDOW ||
getMsgAuthoritativeEngineBoots()>=2147483647){
#endif
#if DISABLE_MAET == 1
if (request->msgAuthoritativeEngineBoots != getMsgAuthoritativeEngineBoots() ||
getMsgAuthoritativeEngineBoots()>=2147483647){
#endif
/*sz*/
/* Changed not working abs(request->msgAuthoritativeEngineTime - getSysUpTime()) < TIME_WINDOW)*/
/* to line above.
/* added line getMsgAuthoritativeEngineBoots()>=2147483647 in if above */
/* to stop the SNMP Agent when the maximum snmpEngineBoots is reached*/
/* and send an Not in Time Window Message back.*/
/*sz*/
TRY(report(request, &usmStatsNotInTimeWindows, &usmStatsNotInTimeWindowsCounter));
return ERR_USM;
}
/*sz*/
#endif /*#if ENABLE_AUTH*/ /*sz*/
#if ENABLE_PRIVACY
if (!(request->msgFlags & FLAG_PRIV))
{
#if PDEBUG
printf("USM Modul: Error! User needs Privacy\n");
#endif
TRY(report(request, &usmStatsUnsupportedSecurityLevel, &usmStatsUnsupportedSecurityLevelCounter));
return ERR_USM;
}
#endif
/*sz*/
if (request->msgFlags & FLAG_PRIV) {
#if ENABLE_PRIVACY
if (request->msgPrivacyParameters.len != 8) {
TRY(report(request, &usmStatsDecryptionErrors, &usmStatsDecryptionErrorsCounter));
return ERR_USM;
}
/* init IV */
u8t iv[16];
convert_2_octets(iv, request->msgAuthoritativeEngineBoots);
convert_2_octets(iv + 4, request->msgAuthoritativeEngineTime);
memcpy(iv + 8, request->msgPrivacyParameters.ptr, 8);
/* decode the Scoped PDU */
aes_process(getPrivKul(), iv, input + *pos, input + *pos, input_len - *pos, AES_DECRYPT);
#else
return FAILURE;
#endif
}
return 0;
}
static s8t encode_USM_parameters(message_v3_t* message, u8t* output, u16t buf_len, s16t* pos) {
if (message->msgFlags & FLAG_PRIV) {
#if ENABLE_PRIVACY
u8t iv[16];
/* IV */
convert_2_octets(iv, message->msgAuthoritativeEngineBoots);
convert_2_octets(iv + 4, message->msgAuthoritativeEngineTime);
/* privace parameters */
convert_2_octets(message->msgPrivacyParameters.ptr, getLPrivacyParameters());
convert_2_octets(message->msgPrivacyParameters.ptr, getHPrivacyParameters());
memcpy(iv + 8, message->msgPrivacyParameters.ptr, 8);
aes_process(getPrivKul(), iv, output + *pos, output + *pos, buf_len - *pos, AES_ENCRYPT);
TRY(ber_encode_type_length(output, pos, BER_TYPE_OCTET_STRING, buf_len - *pos));
#else
return FAILURE;
#endif
}
s16t tmpPos = *pos;
TRY(ber_encode_fixed_string(output, pos, message->msgPrivacyParameters.ptr, message->msgPrivacyParameters.len));
TRY(ber_encode_fixed_string(output, pos, message->msgAuthenticationParameters.ptr, message->msgAuthenticationParameters.len));
message->msgAuthenticationParameters.ptr = &output[*pos + 2];
TRY(ber_encode_fixed_string(output, pos, message->msgUserName.ptr, message->msgUserName.len));
TRY(ber_encode_integer(output, pos, BER_TYPE_INTEGER, message->msgAuthoritativeEngineTime));
TRY(ber_encode_integer(output, pos, BER_TYPE_INTEGER, message->msgAuthoritativeEngineBoots));
TRY(ber_encode_fixed_string(output, pos, message->msgAuthoritativeEngineID.ptr, message->msgAuthoritativeEngineID.len));
TRY(ber_encode_type_length(output, pos, BER_TYPE_SEQUENCE, tmpPos - *pos));
TRY(ber_encode_type_length(output, pos, BER_TYPE_OCTET_STRING, tmpPos - *pos));
return 0;
}
s8t prepareOutgoingMsg_USM(message_v3_t* message, u8t* output, u16t output_len, s16t* pos)
{
memcpy(&message->msgAuthoritativeEngineID, getEngineID(), sizeof(ptr_t));
message->msgAuthoritativeEngineBoots = getMsgAuthoritativeEngineBoots();
message->msgAuthoritativeEngineTime = getSysUpTime()/100;
encode_USM_parameters(message, output, output_len, pos);
return 0;
}
