uint8_t SNMPv3AESEncryptResponseScopedPdu(SNMPV3_RESPONSE_WHOLEMSG* plain_text/*uint8_t userDBIndex*/)
{
uint8_t* cryptoKey;
uint8_t* initVector;
uint8_t* plainText;
uint16_t plaintextLen;
uint8_t* encrypted_text;
uint8_t extraMemReqd;
AES_ROUND_KEYS_128_BIT round_keys;
AES_CFB_STATE_DATA current_stream;
SNMPV3_PROCESSING_MEM_INFO_PTRS snmpv3PktProcessingMemPntr;
SNMPV3_STACK_DCPT_STUB * snmpv3EngnDcptMemoryStubPtr=0;
SNMPv3GetPktProcessingDynMemStubPtrs(&snmpv3PktProcessingMemPntr);
snmpv3EngnDcptMemoryStubPtr=snmpv3PktProcessingMemPntr.snmpv3StkProcessingDynMemStubPtr;
//This is a secured request. Compute the AES Encryption IV
SNMPv3UsmAesEncryptDecrptInitVector(SNMP_RESPONSE_PDU);
plaintextLen= (plain_text->scopedPduStructLen);
cryptoKey=snmpv3EngnDcptMemoryStubPtr->UserInfoDataBase[snmpv3EngnDcptMemoryStubPtr->UserInfoDataBaseIndx].userPrivPswdLoclizdKey;
initVector=snmpV3AesEncryptInitVector;
plainText=(plain_text->scopedPduOffset);
extraMemReqd=(16-(plaintextLen%16)); //AES Blocks are in multiples of 16 Bytes
encrypted_text=(uint8_t*)(TCPIP_HEAP_Calloc(snmpv3PktProcessingMemPntr.snmpHeapMemHandler,1,(size_t)plaintextLen+extraMemReqd));
if(encrypted_text != NULL)
{
AESCreateRoundKeys (&round_keys,cryptoKey,AES_KEY_SIZE_128_BIT);
memcpy(current_stream.initial_vector,initVector,16);
AESCFBEncrypt(encrypted_text,plainText, plaintextLen,
&round_keys, ¤t_stream,
AES_STREAM_START | AES_USE_CFB128 );
}
else
return SNMPV3_MSG_PRIV_FAIL;
//Copy decrypted text to already allocated WholeMsg dynamic memory Buffer.
memcpy(plainText,encrypted_text,plaintextLen);
//free this temp buffer used for decryption purpose.
TCPIP_HEAP_Free(snmpv3PktProcessingMemPntr.snmpHeapMemHandler, encrypted_text);
return SNMPV3_MSG_PRIV_PASS;
}
/****************************************************************************
Function:
uint8_t SNMPv3AESDecryptRxedScopedPdu(void)
Summary:
Incoming SNMPv3 scoped PDU decryption using AES decryption protocol.
Description:
This routine decrypts SNMPV3 incoming PDU using AES protocol , but before this
encrypted data length is verified.If the length of the encrypted OCTECT-STRING
is not multiple of 8, then dryption will be halted.
RFC - 3414. ( section 8)
Precondition:
SNMPv3Init() and ProcessVariabels() are called.
Parameters:
None
Return Values:
SNMPV3_MSG_PRIV_FAIL - Failure
SNMPV3_MSG_PRIV_PASS - Success
Remarks:
None
***************************************************************************/
uint8_t SNMPv3AESDecryptRxedScopedPdu(/*uint8_t userDBIndex*/)
{
uint8_t* cryptoKey;
uint8_t* initVector;
uint8_t* snmpv3_cipher_text;
uint16_t cipherTextLen;
uint8_t* decrypted_text;
uint16_t temp;
uint8_t extraMemReqd;
AES_ROUND_KEYS_128_BIT round_keys;
AES_CFB_STATE_DATA current_stream;
SNMPV3_PROCESSING_MEM_INFO_PTRS snmpv3PktProcessingMemPntr;
SNMPV3_STACK_DCPT_STUB * snmpv3EngnDcptMemoryStubPtr=0;
SNMPv3GetPktProcessingDynMemStubPtrs(&snmpv3PktProcessingMemPntr);
snmpv3EngnDcptMemoryStubPtr=snmpv3PktProcessingMemPntr.snmpv3StkProcessingDynMemStubPtr;
cryptoKey=snmpv3EngnDcptMemoryStubPtr->UserInfoDataBase[snmpv3EngnDcptMemoryStubPtr->UserInfoDataBaseIndx].userPrivPswdLoclizdKey;
initVector=snmpV3AesDecryptInitVector;
temp=snmpv3EngnDcptMemoryStubPtr->InPduWholeMsgBuf.scopedPduOffset;
snmpv3_cipher_text=(snmpv3EngnDcptMemoryStubPtr->InPduWholeMsgBuf.snmpMsgHead+temp);
cipherTextLen= snmpv3EngnDcptMemoryStubPtr->InPduWholeMsgBuf.scopedPduStructLen;
extraMemReqd=(16-(cipherTextLen%16)); //AES Blocks are in multiples of 16 Bytes
decrypted_text=(uint8_t*)(TCPIP_HEAP_Calloc(snmpv3PktProcessingMemPntr.snmpHeapMemHandler,1,(size_t)cipherTextLen+extraMemReqd));
if(decrypted_text != NULL)
{
AESCreateRoundKeys (&round_keys,cryptoKey,AES_KEY_SIZE_128_BIT);
memcpy(current_stream.initial_vector,initVector,16);
AESCFBDecrypt(decrypted_text,snmpv3_cipher_text, cipherTextLen,
&round_keys, ¤t_stream,
AES_STREAM_START | AES_USE_CFB128);
}
else
return SNMPV3_MSG_PRIV_FAIL;
//Copy decrypted text to already allocated WholeMsg dynamic memory Buffer.
memcpy(snmpv3_cipher_text,decrypted_text,cipherTextLen);
//free this temp buffer used for decryption purpose.
TCPIP_HEAP_Free(snmpv3PktProcessingMemPntr.snmpHeapMemHandler, decrypted_text);
return SNMPV3_MSG_PRIV_PASS;
}
BYTE Snmpv3AESEncryptResponseScopedPdu(SNMPV3_RESPONSE_WHOLEMSG* plain_text)
{
UINT8* cryptoKey;
UINT8* initVector;
UINT8* plainText;
WORD plaintextLen;
UINT8* encrypted_text;
BYTE extraMemReqd;
AES_ROUND_KEYS_128_BIT round_keys;
AES_CFB_STATE_DATA current_stream;
//This is a secured request. Compute the AES Encryption IV
Snmpv3UsmAesEncryptDecryptInitVector(SNMP_RESPONSE_PDU);
plaintextLen= (plain_text->scopedPduStructLen);
cryptoKey=snmpV3UserDataBase[gSnmpv3UserDBIndex].userPrivPswdLoclizdKey;
initVector=snmpV3AesEncryptInitVector;
plainText=(plain_text->scopedPduOffset);
extraMemReqd=(16-(plaintextLen%16)); //AES Blocks are in multiples of 16 Bytes
encrypted_text=(UINT8*)(malloc((size_t)plaintextLen+extraMemReqd));
if(encrypted_text != NULL)
{
AESCreateRoundKeys (&round_keys,cryptoKey,AES_KEY_SIZE_128_BIT);
memcpy(current_stream.initial_vector,initVector,16);
AESCFBEncrypt(encrypted_text,plainText, plaintextLen,
&round_keys, ¤t_stream,
AES_STREAM_START | AES_USE_CFB128 );
}
else
return SNMPV3_MSG_PRIV_FAIL;
//Copy decrypted text to already allocated WholeMsg dynamic memory Buffer.
memcpy(plainText,encrypted_text,plaintextLen);
//free this temp buffer used for decryption purpose.
free(encrypted_text);
return SNMPV3_MSG_PRIV_PASS;
}
BYTE Snmpv3AESDecryptRxedScopedPdu(void)
{
UINT8* cryptoKey;
UINT8* initVector;
UINT8* cipher_text;
WORD cipherTextLen;
UINT8* decrypted_text;
WORD temp;
BYTE extraMemReqd;
AES_ROUND_KEYS_128_BIT round_keys;
AES_CFB_STATE_DATA current_stream;
cryptoKey=snmpV3UserDataBase[gSnmpv3UserDBIndex].userPrivPswdLoclizdKey;
initVector=snmpV3AesDecryptInitVector;
temp=gSnmpV3InPduWholeMsgBuf.scopedPduOffset;
cipher_text=(gSnmpV3InPduWholeMsgBuf.snmpMsgHead+temp);
cipherTextLen= gSnmpV3InPduWholeMsgBuf.scopedPduStructLen;
extraMemReqd=(16-(cipherTextLen%16)); //AES Blocks are in multiples of 16 Bytes
decrypted_text=(BYTE*)(malloc((size_t)cipherTextLen+extraMemReqd));
if(decrypted_text != NULL)
{
AESCreateRoundKeys (&round_keys,cryptoKey,AES_KEY_SIZE_128_BIT);
memcpy(current_stream.initial_vector,initVector,16);
AESCFBDecrypt(decrypted_text,cipher_text, cipherTextLen,
&round_keys, ¤t_stream,
AES_STREAM_START | AES_USE_CFB128);
}
else
return SNMPV3_MSG_PRIV_FAIL;
//Copy decrypted text to already allocated WholeMsg dynamic memory Buffer.
memcpy(cipher_text,decrypted_text,cipherTextLen);
//free this temp buffer used for decryption purpose.
free(decrypted_text);
return SNMPV3_MSG_PRIV_PASS;
}