Rewrite security personalization data validation (#885)
* Data is not validated on Linux systems * If encryption is enabled, data is also validated even if signing is disabled.
This commit is contained in:
Patrick Fallberg
committed by
Thomas Mørch
Thomas Mørch
parent
ff0953dd05
commit
4ea0c88ac8
+92
-34
@@ -38,10 +38,11 @@
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#error You have to pick one and only one signing backend
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#endif
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#ifdef MY_SIGNING_FEATURE
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uint8_t _doSign[32]; // Bitfield indicating which sensors require signed communication
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uint8_t _doWhitelist[32]; // Bitfield indicating which sensors require serial salted signatures
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MyMessage _msgSign; // Buffer for message to sign.
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uint8_t _signingNonceStatus;
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static uint8_t _doSign[32]; // Bitfield indicating which sensors require signed communication
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static uint8_t _doWhitelist[32]; // Bitfield indicating which sensors require salted signatures
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static MyMessage _msgSign; // Buffer for message to sign.
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static uint8_t _signingNonceStatus;
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static bool stateValid = false;
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#ifdef MY_NODE_LOCK_FEATURE
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static uint8_t nof_nonce_requests = 0;
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@@ -98,9 +99,25 @@ static void prepareSigningPresentation(MyMessage &msg, uint8_t destination);
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static bool signerInternalProcessPresentation(MyMessage &msg);
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static bool signerInternalProcessNonceRequest(MyMessage &msg);
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static bool signerInternalProcessNonceResponse(MyMessage &msg);
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#if defined(MY_ENCRYPTION_FEATURE) || defined(MY_SIGNING_FEATURE)
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static bool signerInternalValidatePersonalization(void);
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#endif
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void signerInit(void)
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{
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#if defined(MY_SIGNING_FEATURE)
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stateValid = true;
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#endif
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#if defined (MY_ENCRYPTION_FEATURE) || defined (MY_SIGNING_FEATURE)
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if (!signerInternalValidatePersonalization()) {
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SIGN_DEBUG(PSTR("!SGN:PER:TAMPERED\n"));
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#if defined(MY_SIGNING_FEATURE)
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stateValid = false;
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#endif
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} else {
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SIGN_DEBUG(PSTR("SGN:PER:OK\n"));
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}
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#endif
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#if defined(MY_SIGNING_FEATURE)
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// Read out the signing requirements from EEPROM
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hwReadConfigBlock((void*)_doSign, (void*)EEPROM_SIGNING_REQUIREMENT_TABLE_ADDRESS,
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@@ -182,38 +199,44 @@ bool signerSignMsg(MyMessage &msg)
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if (skipSign(msg)) {
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ret = true;
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} else {
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// Send nonce-request
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_signingNonceStatus=SIGN_WAITING_FOR_NONCE;
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if (!_sendRoute(build(_msgSign, msg.destination, msg.sensor, C_INTERNAL,
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I_NONCE_REQUEST).set(""))) {
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SIGN_DEBUG(PSTR("!SGN:SGN:NCE REQ,TO=%d FAIL\n"),
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msg.destination); // Failed to transmit nonce request!
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// Before starting, validate that our state is good, or signing will fail
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if (!stateValid) {
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SIGN_DEBUG(PSTR("!SGN:SGN:STATE\n")); // Signing system is not in a valid state
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ret = false;
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} else {
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SIGN_DEBUG(PSTR("SGN:SGN:NCE REQ,TO=%d\n"), msg.destination); // Nonce requested
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// We have to wait for the nonce to arrive before we can sign our original message
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// Other messages could come in-between. We trust _process() takes care of them
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unsigned long enter = hwMillis();
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_msgSign = msg; // Copy the message to sign since buffer might be touched in _process()
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while (hwMillis() - enter < MY_VERIFICATION_TIMEOUT_MS &&
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_signingNonceStatus==SIGN_WAITING_FOR_NONCE) {
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_process();
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}
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if (hwMillis() - enter > MY_VERIFICATION_TIMEOUT_MS) {
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SIGN_DEBUG(PSTR("!SGN:SGN:NCE TMO\n")); // Timeout waiting for nonce!
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// Send nonce-request
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_signingNonceStatus=SIGN_WAITING_FOR_NONCE;
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if (!_sendRoute(build(_msgSign, msg.destination, msg.sensor, C_INTERNAL,
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I_NONCE_REQUEST).set(""))) {
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SIGN_DEBUG(PSTR("!SGN:SGN:NCE REQ,TO=%d FAIL\n"),
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msg.destination); // Failed to transmit nonce request!
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ret = false;
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} else {
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if (_signingNonceStatus == SIGN_OK) {
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// process() received a nonce and signerProcessInternal successfully signed the message
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msg = _msgSign; // Write the signed message back
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SIGN_DEBUG(PSTR("SGN:SGN:SGN\n")); // Message to send has been signed
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ret = true;
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// After this point, only the 'last' member of the message structure is allowed to be
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// altered if the message has been signed, or signature will become invalid and the
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// message rejected by the receiver
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} else {
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SIGN_DEBUG(PSTR("!SGN:SGN:SGN FAIL\n")); // Message to send could not be signed!
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SIGN_DEBUG(PSTR("SGN:SGN:NCE REQ,TO=%d\n"), msg.destination); // Nonce requested
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// We have to wait for the nonce to arrive before we can sign our original message
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// Other messages could come in-between. We trust _process() takes care of them
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unsigned long enter = hwMillis();
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_msgSign = msg; // Copy the message to sign since buffer might be touched in _process()
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while (hwMillis() - enter < MY_VERIFICATION_TIMEOUT_MS &&
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_signingNonceStatus==SIGN_WAITING_FOR_NONCE) {
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_process();
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}
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if (hwMillis() - enter > MY_VERIFICATION_TIMEOUT_MS) {
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SIGN_DEBUG(PSTR("!SGN:SGN:NCE TMO\n")); // Timeout waiting for nonce!
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ret = false;
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} else {
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if (_signingNonceStatus == SIGN_OK) {
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// process() received a nonce and signerProcessInternal successfully signed the message
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msg = _msgSign; // Write the signed message back
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SIGN_DEBUG(PSTR("SGN:SGN:SGN\n")); // Message to send has been signed
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ret = true;
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// After this point, only the 'last' member of the message structure is allowed to be
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// altered if the message has been signed, or signature will become invalid and the
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// message rejected by the receiver
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} else {
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SIGN_DEBUG(PSTR("!SGN:SGN:SGN FAIL\n")); // Message to send could not be signed!
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ret = false;
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}
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}
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}
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}
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@@ -256,11 +279,17 @@ bool signerVerifyMsg(MyMessage &msg)
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SIGN_DEBUG(PSTR("!SGN:VER:NSG\n")); // Message is not signed, but it should have been!
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verificationResult = false;
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} else {
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if (!signerBackendVerifyMsg(msg)) {
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SIGN_DEBUG(PSTR("!SGN:VER:FAIL\n")); // Signature verification failed!
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// Before starting, validate that our state is good, or signing will fail
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if (!stateValid) {
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SIGN_DEBUG(PSTR("!SGN:VER:STATE\n")); // Signing system is not in a valid state
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verificationResult = false;
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} else {
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SIGN_DEBUG(PSTR("SGN:VER:OK\n"));
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if (!signerBackendVerifyMsg(msg)) {
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SIGN_DEBUG(PSTR("!SGN:VER:FAIL\n")); // Signature verification failed!
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verificationResult = false;
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} else {
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SIGN_DEBUG(PSTR("SGN:VER:OK\n"));
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}
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}
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#if defined(MY_NODE_LOCK_FEATURE)
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if (verificationResult) {
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@@ -533,3 +562,32 @@ static bool signerInternalProcessNonceResponse(MyMessage &msg)
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#endif
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return true; // No need to further process I_NONCE_RESPONSE
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}
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#if defined(MY_ENCRYPTION_FEATURE) || defined(MY_SIGNING_FEATURE)
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static bool signerInternalValidatePersonalization(void)
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{
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#ifdef __linux__
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// Personalization on linux is a bit more crude
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return true;
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#else
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uint8_t buffer[32];
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uint8_t* hash;
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uint8_t checksum;
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signerSha256Init();
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hwReadConfigBlock((void*)buffer, (void*)EEPROM_SIGNING_SOFT_HMAC_KEY_ADDRESS, 32);
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signerSha256Update(buffer, 32);
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hwReadConfigBlock((void*)buffer, (void*)EEPROM_RF_ENCRYPTION_AES_KEY_ADDRESS, 16);
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signerSha256Update(buffer, 16);
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hwReadConfigBlock((void*)buffer, (void*)EEPROM_SIGNING_SOFT_SERIAL_ADDRESS, 9);
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signerSha256Update(buffer, 9);
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hash = signerSha256Final();
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hwReadConfigBlock((void*)&checksum, (void*)EEPROM_PERSONALIZATION_CHECKSUM_ADDRESS, 1);
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if (checksum != hash[0]) {
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return false;
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} else {
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return true;
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}
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#endif
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}
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#endif
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