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Let signing backend validate personalization (#873)

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For soft signing, let backend handle checksum verification of
personalization data. This ensures that the backends sha256 library is
used and avoids an unnecessary instanitation of the public library.
For atsha204 signing, no checksum verification is made, just chip
locking flags.

Fixes #872
This commit is contained in:
Patrick Fallberg
2017-06-06 09:51:37 +02:00
committed by GitHub
parent e6925f69e8
commit 29fd6d6345
2 changed files with 31 additions and 32 deletions
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core/MySigning.cpp
-30
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@@ -90,7 +90,6 @@ extern bool signerAtsha204SignMsg(MyMessage &msg);
#define signerBackendVerifyMsg signerAtsha204VerifyMsg
#define signerBackendSignMsg signerAtsha204SignMsg
#endif
static bool signerValidatePersonalization(void);
static bool skipSign(MyMessage &msg);
#else // not MY_SIGNING_FEATURE
#define signerBackendCheckTimer() true
@@ -103,8 +102,6 @@ static bool signerInternalProcessNonceResponse(MyMessage &msg);
void signerInit(void)
{
#if defined(MY_SIGNING_FEATURE)
(void)signerValidatePersonalization();
// Read out the signing requirements from EEPROM
hwReadConfigBlock((void*)_doSign, (void*)EEPROM_SIGNING_REQUIREMENT_TABLE_ADDRESS,
sizeof(_doSign));
@@ -341,33 +338,6 @@ int signerMemcmp(const void* a, const void* b, size_t sz)
#if defined(MY_SIGNING_FEATURE)
// Helper function to centralize signing/verification exceptions
static bool signerValidatePersonalization(void)
{
#ifdef MY_SIGNING_SIMPLE_PASSWD
return true;
#else
uint8_t buffer[32];
uint8_t* hash;
uint8_t checksum;
signerSha256Init();
hwReadConfigBlock((void*)buffer, (void*)EEPROM_SIGNING_SOFT_HMAC_KEY_ADDRESS, 32);
signerSha256Update(buffer, 32);
hwReadConfigBlock((void*)buffer, (void*)EEPROM_RF_ENCRYPTION_AES_KEY_ADDRESS, 16);
signerSha256Update(buffer, 16);
hwReadConfigBlock((void*)buffer, (void*)EEPROM_SIGNING_SOFT_SERIAL_ADDRESS, 9);
signerSha256Update(buffer, 9);
hash = signerSha256Final();
hwReadConfigBlock((void*)&checksum, (void*)EEPROM_PERSONALIZATION_CHECKSUM_ADDRESS, 1);
if (checksum != hash[0]) {
SIGN_DEBUG(PSTR("!SGN:PER:TAMPERED\n"));
return false;
} else {
SIGN_DEBUG(PSTR("SGN:PER:OK\n"));
return true;
}
#endif
}
static bool skipSign(MyMessage &msg)
{
bool ret = false;