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Secure random & reject unknown LTK #16

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Jan 4, 2021
Merged

Secure random & reject unknown LTK #16

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d9fb4bc
Secure random & reject unknown LTK
Jan 4, 2021
fb2b817
Merge branch 'master' into secure-random
Jan 4, 2021
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18 changes: 13 additions & 5 deletions src/local/BLELocalDevice.h
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Original file line number Diff line number Diff line change
Expand Up @@ -91,11 +91,19 @@ class BLELocalDevice {
virtual bool pairable();
virtual bool paired();

/// TODO: Put in actual variable names
virtual void setStoreIRK(int (*storeIRK)(uint8_t*, uint8_t*));
virtual void setGetIRKs(int (*getIRKs)(uint8_t* nIRKs, uint8_t** BADDR_type, uint8_t*** BADDRs, uint8_t*** IRKs));
virtual void setStoreLTK(int (*storeLTK)(uint8_t*, uint8_t*));
virtual void setGetLTK(int (*getLTK)(uint8_t*, uint8_t*));
// address - The mac to store
// IRK - The IRK to store with this mac
virtual void setStoreIRK(int (*storeIRK)(uint8_t* address, uint8_t* IRK));
// nIRKs - the number of IRKs being provided.
// BDAddrType - an array containing the type of each address (0 public, 1 static random)
// BDAddrs - an array containing the list of addresses
virtual void setGetIRKs(int (*getIRKs)(uint8_t* nIRKs, uint8_t** BDAddrType, uint8_t*** BDAddrs, uint8_t*** IRKs));
// address - the address to store [6 bytes]
// LTK - the LTK to store with this mac [16 bytes]
virtual void setStoreLTK(int (*storeLTK)(uint8_t* address, uint8_t* LTK));
// address - The mac address needing its LTK
// LTK - 16 octet LTK for the mac address
virtual void setGetLTK(int (*getLTK)(uint8_t* address, uint8_t* LTK));
uint8_t BDaddress[6];

protected:
Expand Down
132 changes: 94 additions & 38 deletions src/utility/HCI.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,8 @@
#include "L2CAPSignaling.h"
#include "btct.h"
#include "HCI.h"
#include "bitDescriptions.h"
// #define _BLE_TRACE_

//#define _BLE_TRACE_

Expand Down Expand Up @@ -1141,50 +1143,63 @@ void HCIClass::handleEventPkt(uint8_t /*plen*/, uint8_t pdata[])
// Load our LTK for this connection.
uint8_t peerAddr[7];
uint8_t resolvableAddr[6];
uint8_t foundLTK;
ATT.getPeerAddrWithType(ltkRequest->connectionHandle, peerAddr);

if(ATT.getPeerResolvedAddress(ltkRequest->connectionHandle, resolvableAddr)
&& !((ATT.getPeerEncryption(ltkRequest->connectionHandle) & PEER_ENCRYPTION::PAIRING_REQUEST)>0)){
_getLTK(resolvableAddr, HCI.LTK);
if((ATT.getPeerEncryption(ltkRequest->connectionHandle) & PEER_ENCRYPTION::PAIRING_REQUEST)>0){
// Pairing request - LTK is one in buffer already
foundLTK = 1;
}else{
_getLTK(&peerAddr[1], HCI.LTK);
if(ATT.getPeerResolvedAddress(ltkRequest->connectionHandle, resolvableAddr)){
foundLTK = getLTK(resolvableAddr, HCI.LTK);
}else{
foundLTK = getLTK(&peerAddr[1], HCI.LTK);
}
}
// }
// } //2d
// Send our LTK back
struct __attribute__ ((packed)) LTKReply
{
uint16_t connectionHandle;
uint8_t LTK[16];
} ltkReply = {0,0};
ltkReply.connectionHandle = ltkRequest->connectionHandle;
for(int i=0; i<16; i++) ltkReply.LTK[15-i] = HCI.LTK[i];
int result = sendCommand(OGF_LE_CTL << 10 | LE_COMMAND::LONG_TERM_KEY_REPLY,sizeof(ltkReply), &ltkReply);

#ifdef _BLE_TRACE_
Serial.println("Sending LTK as: ");
btct.printBytes(ltkReply.LTK,16);
#endif

if(result == 0){
struct __attribute__ ((packed)) LTKReplyResult
if(foundLTK){
struct __attribute__ ((packed)) LTKReply
{
uint8_t status;
uint16_t connectionHandle;
} ltkReplyResult = {0,0};
memcpy(&ltkReplyResult, _cmdResponse, 3);

#ifdef _BLE_TRACE_
Serial.println("LTK send success");
Serial.print("status : ");
btct.printBytes(&ltkReplyResult.status,1);
Serial.print("Conn Handle: ");
btct.printBytes((uint8_t*)&ltkReplyResult.connectionHandle,2);
#endif
uint8_t LTK[16];
} ltkReply = {0,0};
ltkReply.connectionHandle = ltkRequest->connectionHandle;
for(int i=0; i<16; i++) ltkReply.LTK[15-i] = HCI.LTK[i];
int result = sendCommand(OGF_LE_CTL << 10 | LE_COMMAND::LONG_TERM_KEY_REPLY,sizeof(ltkReply), &ltkReply);

#ifdef _BLE_TRACE_
Serial.println("Sending LTK as: ");
btct.printBytes(ltkReply.LTK,16);
#endif

if(result == 0){
struct __attribute__ ((packed)) LTKReplyResult
{
uint8_t status;
uint16_t connectionHandle;
} ltkReplyResult = {0,0};
memcpy(&ltkReplyResult, _cmdResponse, 3);

#ifdef _BLE_TRACE_
Serial.println("LTK send success");
Serial.print("status : ");
btct.printBytes(&ltkReplyResult.status,1);
Serial.print("Conn Handle: ");
btct.printBytes((uint8_t*)&ltkReplyResult.connectionHandle,2);
#endif
}else{
#ifdef _BLE_TRACE_
Serial.print("Failed to send LTK...: ");
btct.printBytes((uint8_t*)&result,2);
#endif
}
}else{
/// do LTK rejection
#ifdef _BLE_TRACE_
Serial.print("Failed to send LTK...: ");
btct.printBytes((uint8_t*)&result,2);
Serial.println("LTK not found, rejecting");
#endif
sendCommand(OGF_LE_CTL << 10 | LE_COMMAND::LONG_TERM_KEY_NEGATIVE_REPLY,2, &ltkRequest->connectionHandle);
}
break;
}
Expand Down Expand Up @@ -1258,10 +1273,10 @@ void HCIClass::handleEventPkt(uint8_t /*plen*/, uint8_t pdata[])


uint8_t Z = 0;
for(int i=0; i<16; i++){
/// TODO: Implement secure random
Nb[i] = rand(); //// Should use ESP or ECCx08
}

HCI.leRand(Nb);
HCI.leRand(&Nb[8]);

#ifdef _BLE_TRACE_
Serial.print("nb: ");
btct.printBytes(Nb, 16);
Expand Down Expand Up @@ -1413,6 +1428,47 @@ int HCIClass::leEncrypt(uint8_t* key, uint8_t* plaintext, uint8_t* status, uint8
#endif
return res;
}
int HCIClass::leRand(uint8_t rand[]){
int res = sendCommand(OGF_LE_CTL << 10 | LE_COMMAND::RANDOM);
if(res == 0){
memcpy(rand,_cmdResponse, 8); /// backwards but it's a random number
}
return res;
}
int HCIClass::getLTK(uint8_t* address, uint8_t* LTK){
if(_getLTK!=0){
return _getLTK(address, LTK);
}else{
return 0;
}
}
int HCIClass::storeIRK(uint8_t* address, uint8_t* IRK){
if(_storeIRK!=0){
return _storeIRK(address, IRK);
}else{
return 0;
}
}
int HCIClass::storeLTK(uint8_t* address, uint8_t* LTK){
if(_storeLTK!=0){
return _storeLTK(address, LTK);
}else{
return 0;
}
}

/// Stub function to generate parameters for local authreq
AuthReq HCIClass::localAuthreq(){
// If get, set, IRK, LTK all set then we can bond.
AuthReq local = AuthReq();
if(_storeIRK!=0 && _storeLTK!=0 && _getLTK!=0 && _getIRKs!=0){
local.setBonding(true);
}
local.setSC(true);
local.setMITM(true);
local.setCT2(true);
return LOCAL_AUTHREQ;
}

void HCIClass::dumpPkt(const char* prefix, uint8_t plen, uint8_t pdata[])
{
Expand Down
30 changes: 19 additions & 11 deletions src/utility/HCI.h
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Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,7 @@
#define _HCI_H_

#include <Arduino.h>
#include "bitDescriptions.h"

#include "L2CAPSignaling.h"

Expand All @@ -31,11 +32,13 @@
#define OGF_LE_CTL 0x08

enum LE_COMMAND {
ENCRYPT = 0x0017,
LONG_TERM_KEY_REPLY = 0x001A,
READ_LOCAL_P256 = 0x0025,
GENERATE_DH_KEY_V1 = 0x0026,
GENERATE_DH_KEY_V2 = 0x005E
ENCRYPT = 0x0017,
RANDOM = 0x0018,
LONG_TERM_KEY_REPLY = 0x001A,
LONG_TERM_KEY_NEGATIVE_REPLY = 0x1B,
READ_LOCAL_P256 = 0x0025,
GENERATE_DH_KEY_V1 = 0x0026,
GENERATE_DH_KEY_V2 = 0x005E
};
enum LE_META_EVENT {
CONN_COMPLETE = 0x01,
Expand Down Expand Up @@ -91,6 +94,9 @@ class HCIClass {
uint16_t latency, uint16_t supervisionTimeout);
virtual int leCancelConn();
virtual int leEncrypt(uint8_t* Key, uint8_t* plaintext, uint8_t* status, uint8_t* ciphertext);
// Generate a 64 bit random number
virtual int leRand(uint8_t rand[]);
virtual AuthReq localAuthreq();

virtual int saveNewAddress(uint8_t addressType, uint8_t* address, uint8_t* peerIrk, uint8_t* remoteIrk);
virtual int leAddResolvingAddress(uint8_t addressType, uint8_t* address, uint8_t* peerIrk, uint8_t* remoteIrk);
Expand All @@ -110,7 +116,7 @@ class HCIClass {
virtual void debug(Stream& stream);
virtual void noDebug();

// TODO: Send command be private again & use ATT implementation within ATT.
// TODO: Send command be private again & use ATT implementation of send command within ATT.
virtual int sendCommand(uint16_t opcode, uint8_t plen = 0, void* parameters = NULL);
uint8_t remotePublicKeyBuffer[64];
uint8_t remoteDHKeyCheckBuffer[16];
Expand All @@ -119,11 +125,13 @@ class HCIClass {
uint8_t DHKey[32];
uint8_t localAddr[6];
uint8_t LTK[16];

int (*_storeIRK)(uint8_t* address, uint8_t* peerIrk);
int (*_getIRKs)(uint8_t* nIRKs,uint8_t** BADDR_type, uint8_t*** BADDRs, uint8_t*** IRKs);
int (*_storeLTK)(uint8_t*, uint8_t*);
int (*_getLTK)(uint8_t*, uint8_t*);
virtual int getLTK(uint8_t* address, uint8_t* LTK);
virtual int storeLTK(uint8_t* address, uint8_t* LTK);
virtual int storeIRK(uint8_t* address, uint8_t* IRK);
int (*_storeIRK)(uint8_t* address, uint8_t* peerIrk) = 0;
int (*_getIRKs)(uint8_t* nIRKs,uint8_t** BADDR_type, uint8_t*** BADDRs, uint8_t*** IRKs) = 0;
int (*_storeLTK)(uint8_t*, uint8_t*) = 0;
int (*_getLTK)(uint8_t*, uint8_t*) = 0;

private:

Expand Down
20 changes: 10 additions & 10 deletions src/utility/L2CAPSignaling.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -31,8 +31,8 @@
L2CAPSignalingClass::L2CAPSignalingClass() :
_minInterval(0),
_maxInterval(0),
_supervisionTimeout(0)
,_pairing_enabled(1)
_supervisionTimeout(0),
_pairing_enabled(1)
{
}

Expand Down Expand Up @@ -145,14 +145,14 @@ void L2CAPSignalingClass::handleSecurityData(uint16_t connectionHandle, uint8_t
uint8_t initiatorKeyDistribution;
uint8_t responderKeyDistribution;
} *pairingRequest = (PairingRequest*)l2capSignalingHdr->data;


ATT.remoteKeyDistribution = KeyDistribution(pairingRequest->initiatorKeyDistribution);
ATT.localKeyDistribution = KeyDistribution(pairingRequest->responderKeyDistribution);
KeyDistribution rkd(pairingRequest->responderKeyDistribution);
AuthReq req(pairingRequest->authReq);

KeyDistribution responseKD = KeyDistribution();
responseKD.setIdKey(true);

ATT.remoteKeyDistribution = responseKD;// KeyDistribution(pairingRequest->initiatorKeyDistribution);
ATT.localKeyDistribution = responseKD; //KeyDistribution(pairingRequest->responderKeyDistribution);
// KeyDistribution rkd(pairingRequest->responderKeyDistribution);
AuthReq req(pairingRequest->authReq);
#ifdef _BLE_TRACE_
Serial.print("Req has properties: ");
Serial.print(req.Bonding()?"bonding, ":"no bonding, ");
Expand Down Expand Up @@ -180,7 +180,7 @@ void L2CAPSignalingClass::handleSecurityData(uint16_t connectionHandle, uint8_t
uint8_t maxEncSize;
uint8_t initiatorKeyDistribution;
uint8_t responderKeyDistribution;
} response = { CONNECTION_PAIRING_RESPONSE, LOCAL_IOCAP, 0, LOCAL_AUTHREQ, 0x10, responseKD.getOctet(), responseKD.getOctet()};
} response = { CONNECTION_PAIRING_RESPONSE, LOCAL_IOCAP, 0, HCI.localAuthreq().getOctet(), 0x10, responseKD.getOctet(), responseKD.getOctet()};

HCI.sendAclPkt(connectionHandle, SECURITY_CID, sizeof(response), &response);

Expand Down Expand Up @@ -338,7 +338,7 @@ void L2CAPSignalingClass::smCalculateLTKandConfirm(uint16_t handle, uint8_t expe
uint8_t Eb[16];
uint8_t R[16];
uint8_t MasterIOCap[3];
uint8_t SlaveIOCap[3] = {LOCAL_AUTHREQ, 0x0, LOCAL_IOCAP};
uint8_t SlaveIOCap[3] = {HCI.localAuthreq().getOctet(), 0x0, LOCAL_IOCAP};

ATT.getPeerIOCap(handle, MasterIOCap);
for(int i=0; i<16; i++) R[i] = 0;
Expand Down