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Merged
merged 2 commits into from
Jun 7, 2022
Merged

Block cmds till negotiation #147

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c406773
Merge pull request #71 from divegeek/Javacard_KM_41_AOSP_UPMERGE_0630
subrahmanyaman Jun 3, 2022
eeb2d76
Do not allow commands till shared secret is negotiated.
subrahmanyaman Jun 6, 2022
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83 changes: 59 additions & 24 deletions Applet/src/com/android/javacard/keymaster/KMKeymasterApplet.java
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -118,7 +118,7 @@ public class KMKeymasterApplet extends Applet implements AppletEvent, ExtendedLe
private static final byte INS_OEM_LOCK_PROVISIONING_CMD = INS_BEGIN_KM_CMD + 6; //0x06
private static final byte INS_GET_PROVISION_STATUS_CMD = INS_BEGIN_KM_CMD + 7; //0x07
private static final byte INS_SET_VERSION_PATCHLEVEL_CMD = INS_BEGIN_KM_CMD + 8; //0x08
private static final byte INS_SET_BOOT_ENDED_CMD = INS_BEGIN_KM_CMD + 9; //0x09
private static final byte INS_SET_BOOT_ENDED_CMD = INS_BEGIN_KM_CMD + 9; //0x09 // Unused
private static final byte INS_SE_FACTORY_LOCK_PROVISIONING_CMD = INS_BEGIN_KM_CMD + 10; //0x0A
private static final byte INS_PROVISION_OEM_ROOT_PUBLIC_KEY_CMD = INS_BEGIN_KM_CMD + 11; //0x0B
private static final byte INS_OEM_UNLOCK_PROVISIONING_CMD = INS_BEGIN_KM_CMD + 12; //0x0C
Expand Down Expand Up @@ -237,6 +237,17 @@ public class KMKeymasterApplet extends Applet implements AppletEvent, ExtendedLe
public static final short KEYBLOB_CURRENT_VERSION = 1;
// KeyBlob Verion 1 constant.
public static final short KEYBLOB_VERSION_0 = 0;
// Device boot states. Applet starts executing the
// core commands once all the states are set. The commands
// that are allowed irrespective of these states are:
// All the provision commands
// INS_GET_HW_INFO_CMD
// INS_ADD_RNG_ENTROPY_CMD
// INS_COMPUTE_SHARED_HMAC_CMD
// INS_GET_HMAC_SHARING_PARAM_CMD
public static final byte SET_BOOT_PARAMS_SUCCESS = 0x01;
public static final byte SET_SYSTEM_PROPERTIES_SUCCESS = 0x02;
public static final byte NEGOTIATED_SHARED_SECRET_SUCCESS = 0x04;

// Keymaster Applet attributes
protected static byte keymasterState = ILLEGAL_STATE;
Expand Down Expand Up @@ -485,23 +496,15 @@ public void process(APDU apdu) {
&& (!seProvider.isDeviceRebooted())) {
ISOException.throwIt(ISO7816.SW_COMMAND_NOT_ALLOWED);
}
// clear the device reboot status
repository.setDeviceBootStatus((byte) 0x00);
processSetBootParamsCmd(apdu);
//set the flag to mark boot started
repository.setDeviceBootStatus(SET_BOOT_PARAMS_SUCCESS);
seProvider.clearDeviceBooted(false);

sendError(apdu, KMError.OK);
return;

case INS_SET_BOOT_ENDED_CMD:
if (seProvider.isBootSignalEventSupported()
&& (keymasterState == KMKeymasterApplet.ACTIVE_STATE)
&& (!seProvider.isDeviceRebooted())) {
ISOException.throwIt(ISO7816.SW_COMMAND_NOT_ALLOWED);
}
//set the flag to mark boot ended
repository.setBootEndedStatus(true);

seProvider.clearDeviceBooted(false);
sendError(apdu, KMError.OK);
return;

case INS_GET_PROVISION_STATUS_CMD:
processGetProvisionStatusCmd(apdu);
Expand All @@ -512,6 +515,10 @@ public void process(APDU apdu) {
if ((keymasterState == KMKeymasterApplet.ACTIVE_STATE)
|| ((keymasterState == KMKeymasterApplet.IN_PROVISION_STATE)
&& isProvisioningComplete())) {

if (!isKeymasterReady(apduIns)) {
KMException.throwIt(KMError.UNKNOWN_ERROR);
}
switch (apduIns) {
case INS_GENERATE_KEY_CMD:
processGenerateKey(apdu);
Expand Down Expand Up @@ -619,6 +626,39 @@ && isProvisioningComplete())) {
}
}

// After every device boot, the Keymaster becomes ready to execute all the commands only after
// 1. boot parameters are set,
// 2. system properties are set and
// 3. computed the shared secret successfully.
private boolean isKeymasterReady(byte apduIns) {
byte deviceBootStatus =
(SET_BOOT_PARAMS_SUCCESS | SET_SYSTEM_PROPERTIES_SUCCESS |
NEGOTIATED_SHARED_SECRET_SUCCESS);
if (repository.getDeviceBootStatus() == deviceBootStatus) {
// Keymaster is ready to execute all the commands.
return true;
}
// Below commands are allowed even if the Keymaster is not ready.
switch (apduIns) {
case INS_GET_HW_INFO_CMD:
case INS_ADD_RNG_ENTROPY_CMD:
case INS_GET_HMAC_SHARING_PARAM_CMD:
case INS_COMPUTE_SHARED_HMAC_CMD:
case INS_SET_VERSION_PATCHLEVEL_CMD:
case INS_OEM_UNLOCK_PROVISIONING_CMD:
return true;
default:
break;
}
return false;
}

private void setDeviceBootStatus(byte deviceRebootStatus) {
byte status = repository.getDeviceBootStatus();
status |= deviceRebootStatus;
repository.setDeviceBootStatus(status);
}

private void generateUniqueOperationHandle(byte[] buf, short offset, short len) {
do {
seProvider.newRandomNumber(buf, offset, len);
Expand Down Expand Up @@ -854,6 +894,7 @@ private void processSetVersionAndPatchLevels(APDU apdu) {
KMInteger.cast(tmpVariables[2]).getStartOff(),
KMInteger.cast(tmpVariables[2]).length());

setDeviceBootStatus(SET_SYSTEM_PROPERTIES_SUCCESS);
sendError(apdu, KMError.OK);
}

Expand Down Expand Up @@ -1337,6 +1378,7 @@ private void processComputeSharedHmacCmd(APDU apdu) {
(short) sharingCheck.length,
scratchPad,
tmpVariables[6]);
setDeviceBootStatus(NEGOTIATED_SHARED_SECRET_SUCCESS);
// verification signature blob - 32 bytes
tmpVariables[1] = KMByteBlob.instance(scratchPad, tmpVariables[6], tmpVariables[5]);
// prepare the response
Expand Down Expand Up @@ -1682,7 +1724,7 @@ private void processAttestKeyCmd(APDU apdu) {
addTags(
KMKeyCharacteristics.cast(data[KEY_CHARACTERISTICS]).getSoftwareEnforced(), false, cert);

cert.deviceLocked(repository.getBootLoaderLock());
cert.deviceLocked(repository.getBootDeviceLocked());
cert.issuer(getProvisionedCertificateData(KMSEProvider.CERTIFICATE_ISSUER));
cert.publicKey(data[PUB_KEY]);
cert.verifiedBootHash(repository.getVerifiedBootHash());
Expand Down Expand Up @@ -2775,7 +2817,7 @@ private void authorizeAndBeginOperation(KMOperationState op, byte[] scratchPad)
//Validate bootloader only
tmpVariables[0] =
KMKeyParameters.findTag(KMType.BOOL_TAG, KMType.BOOTLOADER_ONLY, data[HW_PARAMETERS]);
if (tmpVariables[0] != KMType.INVALID_VALUE && repository.getBootEndedStatus()) {
if (tmpVariables[0] != KMType.INVALID_VALUE) {
KMException.throwIt(KMError.INVALID_KEY_BLOB);
}

Expand Down Expand Up @@ -3674,11 +3716,7 @@ private void processSetBootParamsCmd(APDU apdu) {
repository.setBootState(enumVal);

enumVal = KMEnum.cast(tmpVariables[4]).getVal();
repository.setBootloaderLocked(enumVal == KMType.DEVICE_LOCKED_TRUE);

// Clear Android system properties expect boot patch level as it is
// already set.
repository.clearAndroidSystemProperties();
repository.setBootDeviceLocked(enumVal == KMType.DEVICE_LOCKED_TRUE);

// Clear the Computed SharedHmac and Hmac nonce from persistent memory.
Util.arrayFillNonAtomic(scratchPad, (short) 0, KMRepository.COMPUTED_HMAC_KEY_SIZE, (byte) 0);
Expand All @@ -3692,9 +3730,6 @@ private void processSetBootParamsCmd(APDU apdu) {
seProvider.newRandomNumber(scratchPad, (short) 0, KMRepository.HMAC_SEED_NONCE_SIZE);
repository.initHmacNonce(scratchPad, (short) 0, KMRepository.HMAC_SEED_NONCE_SIZE);

//flag to maintain the boot state
repository.setBootEndedStatus(false);

//flag to maintain early boot ended state
repository.setEarlyBootEndedStatus(false);

Expand Down
32 changes: 14 additions & 18 deletions Applet/src/com/android/javacard/keymaster/KMRepository.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -70,7 +70,7 @@ public class KMRepository implements KMUpgradable {
public static final byte DEVICE_LOCKED_PASSWORD_ONLY = 22;
// Total 8 auth tags, so the next offset is AUTH_TAG_1 + 8
public static final byte AUTH_TAG_1 = 23;
public static final byte BOOT_ENDED_STATUS = 31;
public static final byte DEVICE_STATUS = 31;
public static final byte EARLY_BOOT_ENDED_STATUS = 32;

// Data Item sizes
Expand All @@ -94,7 +94,7 @@ public class KMRepository implements KMUpgradable {
public static final short AUTH_TAG_LENGTH = 16;
public static final short AUTH_TAG_COUNTER_SIZE = 4;
public static final short AUTH_TAG_ENTRY_SIZE = (AUTH_TAG_LENGTH + AUTH_TAG_COUNTER_SIZE + 1);
public static final short BOOT_ENDED_FLAG_SIZE = 1;
public static final short DEVICE_STATUS_FLAG_SIZE = 1;
public static final short EARLY_BOOT_ENDED_FLAG_SIZE = 1;
private static final byte[] zero = {0, 0, 0, 0, 0, 0, 0, 0};

Expand Down Expand Up @@ -698,7 +698,7 @@ public short getVerifiedBootHash() {
return blob;
}

public boolean getBootLoaderLock() {
public boolean getBootDeviceLocked() {
short blob = readData(BOOT_DEVICE_LOCKED_STATUS);
if (blob == KMType.INVALID_VALUE) {
KMException.throwIt(KMError.INVALID_DATA);
Expand Down Expand Up @@ -770,7 +770,7 @@ public void clearAndroidSystemProperties() {
// boot parameters.
}

public void setBootloaderLocked(boolean flag) {
public void setBootDeviceLocked(boolean flag) {
short start = alloc(BOOT_DEVICE_LOCK_FLAG_SIZE);
if (flag) {
(getHeap())[start] = (byte) 0x01;
Expand Down Expand Up @@ -975,24 +975,20 @@ public short getBackupObjectCount() {
return (short) 1;
}

public boolean getBootEndedStatus() {
short blob = readData(BOOT_ENDED_STATUS);
public byte getDeviceBootStatus() {
short blob = readData(DEVICE_STATUS);
if (blob == KMType.INVALID_VALUE) {
KMException.throwIt(KMError.INVALID_DATA);
}
return (byte) ((getHeap())[KMByteBlob.cast(blob).getStartOff()]) == 0x01;
return (byte) ((getHeap())[KMByteBlob.cast(blob).getStartOff()]);
}

public void setBootEndedStatus(boolean flag) {
short start = alloc(BOOT_ENDED_STATUS);
if (flag) {
(getHeap())[start] = (byte) 0x01;
} else {
(getHeap())[start] = (byte) 0x00;
}
writeDataEntry(BOOT_ENDED_STATUS, getHeap(), start, BOOT_ENDED_FLAG_SIZE);

public void setDeviceBootStatus(byte deviceStatus) {
short start = alloc(DEVICE_STATUS_FLAG_SIZE);
(getHeap())[start] = deviceStatus;
writeDataEntry(DEVICE_STATUS, getHeap(), start, DEVICE_STATUS_FLAG_SIZE);
}

public boolean getEarlyBootEndedStatus() {
short blob = readData(EARLY_BOOT_ENDED_STATUS);
if (blob == KMType.INVALID_VALUE) {
Expand All @@ -1002,7 +998,7 @@ public boolean getEarlyBootEndedStatus() {
}

public void setEarlyBootEndedStatus(boolean flag) {
short start = alloc(EARLY_BOOT_ENDED_STATUS);
short start = alloc(EARLY_BOOT_ENDED_FLAG_SIZE);
if (flag) {
(getHeap())[start] = (byte) 0x01;
} else {
Expand Down