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Security personalizer rewritten (#794)

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* Removed ability to lock data section
* Introduced "guided mode" to simplify process
* Refactored the sketch to be less monolithic
* Print details and instructions in tables
* Use device unique ID as serial when
* Calculate and store personalization checksum
* Print serial in a copy+paste friendly manner (fixes #804)
* Clarify meaning of UART confirmation (fixes #805)
This commit is contained in:
Patrick Fallberg
2017-04-02 15:37:21 +02:00
committed by GitHub
parent 3350d79fe6
commit 7e6db413c7
14 changed files with 1794 additions and 954 deletions
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core/MySigningAtsha204.cpp
+158 -67
View File
@@ -27,7 +27,13 @@
#include "MySigning.h"
#define SIGNING_IDENTIFIER (1)
#define SIGNING_IDENTIFIER (1) //HMAC-SHA256
#if defined(MY_DEBUG_VERBOSE_SIGNING)
#define SIGN_DEBUG(x,...) hwDebugPrint(x, ##__VA_ARGS__)
#else
#define SIGN_DEBUG(x,...)
#endif
// Define MY_DEBUG_VERBOSE_SIGNING in your sketch to enable signing backend debugprints
@@ -47,59 +53,36 @@ const whitelist_entry_t _signing_whitelist[] = MY_SIGNING_NODE_WHITELISTING;
static void signerCalculateSignature(MyMessage &msg, bool signing);
static uint8_t* signerSha256(const uint8_t* data, size_t sz);
static bool init_ok = false;
#ifdef MY_DEBUG_VERBOSE_SIGNING
static char i2h(uint8_t i)
{
uint8_t k = i & 0x0F;
if (k <= 9) {
return '0' + k;
} else {
return 'A' + k - 10;
}
}
static void DEBUG_SIGNING_PRINTBUF(const __FlashStringHelper* str, uint8_t* buf, uint8_t sz)
{
static char printBuffer[300];
if (NULL == buf) {
return;
}
#ifdef MY_GATEWAY_FEATURE
// prepend debug message to be handled correctly by controller (C_INTERNAL, I_LOG_MESSAGE)
snprintf_P(printBuffer, 299, PSTR("0;255;%d;0;%d;"), C_INTERNAL, I_LOG_MESSAGE);
MY_SERIALDEVICE.print(printBuffer);
#endif
for (int i=0; i<sz; i++) {
printBuffer[i * 2] = i2h(buf[i] >> 4);
printBuffer[(i * 2) + 1] = i2h(buf[i]);
}
printBuffer[sz * 2] = '\0';
#ifdef MY_GATEWAY_FEATURE
// Truncate message if this is gateway node
printBuffer[MY_GATEWAY_MAX_SEND_LENGTH-1-strlen_P((const char*)str)] = '\0';
#endif
MY_SERIALDEVICE.print(str);
if (sz > 0) {
MY_SERIALDEVICE.print(printBuffer);
}
MY_SERIALDEVICE.println("");
}
#else
#define DEBUG_SIGNING_PRINTBUF(str, buf, sz)
#endif
void signerAtsha204Init(void)
bool signerAtsha204Init(void)
{
init_ok = true;
atsha204_init(MY_SIGNING_ATSHA204_PIN);
(void)atsha204_wakeup(_signing_temp_message);
// Read the configuration lock flag to determine if device is personalized or not
if (atsha204_read(_signing_tx_buffer, _signing_rx_buffer,
SHA204_ZONE_CONFIG, 0x15<<2) != SHA204_SUCCESS) {
SIGN_DEBUG(PSTR("Could not read ATSHA204A lock config, refusing to use backend\n"));
init_ok = false;
} else if (_signing_rx_buffer[SHA204_BUFFER_POS_DATA+3] != 0x00) {
SIGN_DEBUG(PSTR("ATSHA204A not personalized, refusing to use backend\n"));
init_ok = false;
}
return init_ok;
}
bool signerAtsha204CheckTimer(void)
{
if (!init_ok) {
SIGN_DEBUG(PSTR("Backend not initialized\n"));
return false;
}
if (_signing_verification_ongoing) {
if (hwMillis() < _signing_timestamp ||
hwMillis() > _signing_timestamp + MY_VERIFICATION_TIMEOUT_MS) {
DEBUG_SIGNING_PRINTBUF(F("Verification timeout"), NULL, 0);
SIGN_DEBUG(PSTR("Verification timeout\n"));
// Purge nonce
memset(_signing_signing_nonce, 0x00, NONCE_NUMIN_SIZE_PASSTHROUGH);
memset(_signing_verifying_nonce, 0x00, NONCE_NUMIN_SIZE_PASSTHROUGH);
@@ -112,14 +95,18 @@ bool signerAtsha204CheckTimer(void)
bool signerAtsha204GetNonce(MyMessage &msg)
{
DEBUG_SIGNING_PRINTBUF(F("Signing backend: ATSHA204"), NULL, 0);
if (!init_ok) {
SIGN_DEBUG(PSTR("Backend not initialized\n"));
return false;
}
SIGN_DEBUG(PSTR("Signing backend: ATSHA204\n"));
// Generate random number for use as nonce
// We used a basic whitening technique that XORs each byte in a 32byte random value with current hwMillis() counter
// This 32-byte random value is then hashed (SHA256) to produce the resulting nonce
(void)atsha204_wakeup(_signing_temp_message);
if (atsha204_execute(SHA204_RANDOM, RANDOM_SEED_UPDATE, 0, 0, NULL,
RANDOM_COUNT, _signing_tx_buffer, RANDOM_RSP_SIZE, _signing_rx_buffer) != SHA204_SUCCESS) {
DEBUG_SIGNING_PRINTBUF(F("Failed to generate nonce"), NULL, 0);
SIGN_DEBUG(PSTR("Failed to generate nonce\n"));
return false;
}
for (int i = 0; i < 32; i++) {
@@ -147,7 +134,11 @@ bool signerAtsha204GetNonce(MyMessage &msg)
void signerAtsha204PutNonce(MyMessage &msg)
{
DEBUG_SIGNING_PRINTBUF(F("Signing backend: ATSHA204"), NULL, 0);
if (!init_ok) {
SIGN_DEBUG(PSTR("Backend not initialized\n"));
return;
}
SIGN_DEBUG(PSTR("Signing backend: ATSHA204\n"));
memcpy(_signing_signing_nonce, (uint8_t*)msg.getCustom(), MAX_PAYLOAD);
// We set the part of the 32-byte nonce that does not fit into a message to 0xAA
@@ -158,7 +149,7 @@ bool signerAtsha204SignMsg(MyMessage &msg)
{
// If we cannot fit any signature in the message, refuse to sign it
if (mGetLength(msg) > MAX_PAYLOAD-2) {
DEBUG_SIGNING_PRINTBUF(F("Message too large"), NULL, 0);
SIGN_DEBUG(PSTR("Message too large\n"));
return false;
}
@@ -174,7 +165,10 @@ bool signerAtsha204SignMsg(MyMessage &msg)
atsha204_getSerialNumber(&_signing_signing_nonce[33]);
(void)signerSha256(_signing_signing_nonce,
32+1+SHA204_SERIAL_SZ); // we can 'void' sha256 because the hash is already put in the correct place
DEBUG_SIGNING_PRINTBUF(F("Signature salted with serial"), NULL, 0);
SIGN_DEBUG(PSTR("Signature salted with serial: %02X%02X%02X%02X%02X%02X%02X%02X%02X\n"),
_signing_signing_nonce[33], _signing_signing_nonce[34], _signing_signing_nonce[35],
_signing_signing_nonce[36], _signing_signing_nonce[37], _signing_signing_nonce[38],
_signing_signing_nonce[39], _signing_signing_nonce[40], _signing_signing_nonce[41]);
}
// Put device back to sleep
@@ -186,8 +180,6 @@ bool signerAtsha204SignMsg(MyMessage &msg)
// Transfer as much signature data as the remaining space in the message permits
memcpy(&msg.data[mGetLength(msg)], &_signing_rx_buffer[SHA204_BUFFER_POS_DATA],
MAX_PAYLOAD-mGetLength(msg));
DEBUG_SIGNING_PRINTBUF(F("Signature in message: "), (uint8_t*)&msg.data[mGetLength(msg)],
MAX_PAYLOAD-mGetLength(msg));
return true;
}
@@ -195,7 +187,7 @@ bool signerAtsha204SignMsg(MyMessage &msg)
bool signerAtsha204VerifyMsg(MyMessage &msg)
{
if (!_signing_verification_ongoing) {
DEBUG_SIGNING_PRINTBUF(F("No active verification session"), NULL, 0);
SIGN_DEBUG(PSTR("No active verification session\n"));
return false;
} else {
// Make sure we have not expired
@@ -206,12 +198,10 @@ bool signerAtsha204VerifyMsg(MyMessage &msg)
_signing_verification_ongoing = false;
if (msg.data[mGetLength(msg)] != SIGNING_IDENTIFIER) {
DEBUG_SIGNING_PRINTBUF(F("Incorrect signing identifier"), NULL, 0);
SIGN_DEBUG(PSTR("Incorrect signing identifier\n"));
return false;
}
DEBUG_SIGNING_PRINTBUF(F("Signature in message: "), (uint8_t*)&msg.data[mGetLength(msg)],
MAX_PAYLOAD-mGetLength(msg));
signerCalculateSignature(msg, false); // Get signature of message
#ifdef MY_SIGNING_NODE_WHITELISTING
@@ -219,7 +209,7 @@ bool signerAtsha204VerifyMsg(MyMessage &msg)
size_t j;
for (j=0; j < NUM_OF(_signing_whitelist); j++) {
if (_signing_whitelist[j].nodeId == msg.sender) {
DEBUG_SIGNING_PRINTBUF(F("Sender found in whitelist"), NULL, 0);
SIGN_DEBUG(PSTR("Sender found in whitelist\n"));
memcpy(_signing_verifying_nonce, &_signing_rx_buffer[SHA204_BUFFER_POS_DATA],
32); // We can reuse the nonce buffer now since it is no longer needed
_signing_verifying_nonce[32] = msg.sender;
@@ -230,7 +220,7 @@ bool signerAtsha204VerifyMsg(MyMessage &msg)
}
}
if (j == NUM_OF(_signing_whitelist)) {
DEBUG_SIGNING_PRINTBUF(F("Sender not found in whitelist, message rejected!"), NULL, 0);
SIGN_DEBUG(PSTR("Sender not found in whitelist, message rejected!\n"));
// Put device back to sleep
atsha204_sleep();
return false;
@@ -246,14 +236,13 @@ bool signerAtsha204VerifyMsg(MyMessage &msg)
// Compare the caluclated signature with the provided signature
if (signerMemcmp(&msg.data[mGetLength(msg)], &_signing_rx_buffer[SHA204_BUFFER_POS_DATA],
MAX_PAYLOAD-mGetLength(msg))) {
DEBUG_SIGNING_PRINTBUF(F("Signature bad: "), &_signing_rx_buffer[SHA204_BUFFER_POS_DATA],
MAX_PAYLOAD-mGetLength(msg));
SIGN_DEBUG(PSTR("Signature bad\n"));
#ifdef MY_SIGNING_NODE_WHITELISTING
DEBUG_SIGNING_PRINTBUF(F("Is the sender whitelisted and serial correct?"), NULL, 0);
SIGN_DEBUG(PSTR("Is the sender whitelisted and serial correct?\n"));
#endif
return false;
} else {
DEBUG_SIGNING_PRINTBUF(F("Signature OK"), NULL, 0);
SIGN_DEBUG(PSTR("Signature OK\n"));
return true;
}
}
@@ -268,10 +257,42 @@ static void signerCalculateSignature(MyMessage &msg, bool signing)
MAX_MESSAGE_LENGTH-1-(MAX_PAYLOAD-mGetLength(msg)));
// Program the data to sign into the ATSHA204
DEBUG_SIGNING_PRINTBUF(F("Message to process: "), (uint8_t*)&msg.data[1-HEADER_SIZE],
MAX_MESSAGE_LENGTH-1-(MAX_PAYLOAD-mGetLength(msg)));
DEBUG_SIGNING_PRINTBUF(F("Current nonce: "),
signing ? _signing_signing_nonce : _signing_verifying_nonce, 32);
SIGN_DEBUG(PSTR("Current nonce: "
"%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X"
"%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X\n"),
signing ? _signing_signing_nonce[0] : _signing_verifying_nonce[0],
signing ? _signing_signing_nonce[1] : _signing_verifying_nonce[1],
signing ? _signing_signing_nonce[2] : _signing_verifying_nonce[2],
signing ? _signing_signing_nonce[3] : _signing_verifying_nonce[3],
signing ? _signing_signing_nonce[4] : _signing_verifying_nonce[4],
signing ? _signing_signing_nonce[5] : _signing_verifying_nonce[5],
signing ? _signing_signing_nonce[6] : _signing_verifying_nonce[6],
signing ? _signing_signing_nonce[7] : _signing_verifying_nonce[7],
signing ? _signing_signing_nonce[8] : _signing_verifying_nonce[8],
signing ? _signing_signing_nonce[9] : _signing_verifying_nonce[9],
signing ? _signing_signing_nonce[10] : _signing_verifying_nonce[10],
signing ? _signing_signing_nonce[11] : _signing_verifying_nonce[11],
signing ? _signing_signing_nonce[12] : _signing_verifying_nonce[12],
signing ? _signing_signing_nonce[13] : _signing_verifying_nonce[13],
signing ? _signing_signing_nonce[14] : _signing_verifying_nonce[14],
signing ? _signing_signing_nonce[15] : _signing_verifying_nonce[15],
signing ? _signing_signing_nonce[16] : _signing_verifying_nonce[16],
signing ? _signing_signing_nonce[17] : _signing_verifying_nonce[17],
signing ? _signing_signing_nonce[18] : _signing_verifying_nonce[18],
signing ? _signing_signing_nonce[19] : _signing_verifying_nonce[19],
signing ? _signing_signing_nonce[20] : _signing_verifying_nonce[20],
signing ? _signing_signing_nonce[21] : _signing_verifying_nonce[21],
signing ? _signing_signing_nonce[22] : _signing_verifying_nonce[22],
signing ? _signing_signing_nonce[23] : _signing_verifying_nonce[23],
signing ? _signing_signing_nonce[24] : _signing_verifying_nonce[24],
signing ? _signing_signing_nonce[25] : _signing_verifying_nonce[25],
signing ? _signing_signing_nonce[26] : _signing_verifying_nonce[26],
signing ? _signing_signing_nonce[27] : _signing_verifying_nonce[27],
signing ? _signing_signing_nonce[28] : _signing_verifying_nonce[28],
signing ? _signing_signing_nonce[29] : _signing_verifying_nonce[29],
signing ? _signing_signing_nonce[30] : _signing_verifying_nonce[30],
signing ? _signing_signing_nonce[31] : _signing_verifying_nonce[31]
);
(void)atsha204_execute(SHA204_WRITE, SHA204_ZONE_DATA | SHA204_ZONE_COUNT_FLAG, 8 << 3, 32,
_signing_temp_message,
WRITE_COUNT_LONG, _signing_tx_buffer, WRITE_RSP_SIZE, _signing_rx_buffer);
@@ -293,7 +314,42 @@ static void signerCalculateSignature(MyMessage &msg, bool signing)
(void)atsha204_execute(SHA204_HMAC, HMAC_MODE_SOURCE_FLAG_MATCH, 0, 0, NULL,
HMAC_COUNT, _signing_tx_buffer, HMAC_RSP_SIZE, _signing_rx_buffer);
DEBUG_SIGNING_PRINTBUF(F("HMAC: "), &_signing_rx_buffer[SHA204_BUFFER_POS_DATA], 32);
SIGN_DEBUG(PSTR("HMAC: "
"%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X"
"%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X\n"),
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+0],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+1],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+2],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+3],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+4],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+5],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+6],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+7],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+8],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+9],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+10],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+11],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+12],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+13],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+14],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+15],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+16],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+17],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+18],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+19],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+20],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+21],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+22],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+23],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+24],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+25],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+26],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+27],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+28],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+29],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+30],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+31]
);
}
// Helper to calculate a generic SHA256 digest of provided buffer (only supports one block)
@@ -314,6 +370,41 @@ static uint8_t* signerSha256(const uint8_t* data, size_t sz)
(void)atsha204_execute(SHA204_SHA, SHA_CALC, 0, SHA_MSG_SIZE, _signing_temp_message,
SHA_COUNT_LONG, _signing_tx_buffer, SHA_RSP_SIZE_LONG, _signing_rx_buffer);
DEBUG_SIGNING_PRINTBUF(F("SHA256: "), &_signing_rx_buffer[SHA204_BUFFER_POS_DATA], 32);
SIGN_DEBUG(PSTR("SHA256: "
"%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X"
"%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X\n"),
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+0],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+1],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+2],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+3],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+4],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+5],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+6],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+7],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+8],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+9],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+10],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+11],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+12],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+13],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+14],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+15],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+16],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+17],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+18],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+19],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+20],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+21],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+22],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+23],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+24],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+25],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+26],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+27],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+28],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+29],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+30],
_signing_rx_buffer[SHA204_BUFFER_POS_DATA+31]
);
return &_signing_rx_buffer[SHA204_BUFFER_POS_DATA];
}