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Replace AES-CBC with AES-GCM in SecureDataManager #627

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Replace AES-CBC with AES-GCM in SecureDataManager #627

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57 changes: 11 additions & 46 deletions src/lib/data_mgr/SecureDataManager.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -65,9 +65,6 @@ void SecureDataManager::initObject()
// Set the initial login state
soLoggedIn = userLoggedIn = false;

// Set the magic
magic = ByteString("524A52"); // RJR

// Get a mutex
dataMgrMutex = MutexFactory::i()->getMutex();
}
Expand Down Expand Up @@ -131,25 +128,15 @@ bool SecureDataManager::pbeEncryptKey(const ByteString& passphrase, ByteString&

// Encrypt the data
ByteString block;
ByteString aad;

if (!aes->encryptInit(pbeKey, SymMode::CBC, IV))
{
delete pbeKey;

return false;
}

// First, add the magic
if (!aes->encryptUpdate(magic, block))
if (!aes->encryptInit(pbeKey, SymMode::GCM, IV, true, 0, aad, 16))
{
delete pbeKey;

return false;
}

encryptedKey += block;

// Then, add the key itself
ByteString key;

{
Expand Down Expand Up @@ -269,9 +256,10 @@ bool SecureDataManager::login(const ByteString& passphrase, const ByteString& en
// Decrypt the key data
ByteString decryptedKeyData;
ByteString finalBlock;
ByteString aad;

// NOTE: The login will fail here if incorrect passphrase is supplied
if (!aes->decryptInit(pbeKey, SymMode::CBC, IV) ||
if (!aes->decryptInit(pbeKey, SymMode::GCM, IV, 0, true, aad, 16) ||
!aes->decryptUpdate(encryptedKeyData, decryptedKeyData) ||
!aes->decryptFinal(finalBlock))
{
Expand All @@ -284,23 +272,8 @@ bool SecureDataManager::login(const ByteString& passphrase, const ByteString& en

decryptedKeyData += finalBlock;

// Check the magic
if (decryptedKeyData.substr(0, 3) != magic)
{
// The passphrase was incorrect
DEBUG_MSG("Incorrect passphrase supplied");

return false;
}

// Strip off the magic
ByteString key = decryptedKeyData.substr(3);

// And mask the key
decryptedKeyData.wipe();

MutexLocker lock(dataMgrMutex);
remask(key);
remask(decryptedKeyData);

return true;
}
Expand Down Expand Up @@ -340,9 +313,10 @@ bool SecureDataManager::reAuthenticate(const ByteString& passphrase, const ByteS
// Decrypt the key data
ByteString decryptedKeyData;
ByteString finalBlock;
ByteString aad;

// NOTE: The login will fail here if incorrect passphrase is supplied
if (!aes->decryptInit(pbeKey, SymMode::CBC, IV) ||
if (!aes->decryptInit(pbeKey, SymMode::GCM, IV, true, 0, aad, 16) ||
!aes->decryptUpdate(encryptedKeyData, decryptedKeyData) ||
!aes->decryptFinal(finalBlock))
{
Expand All @@ -353,17 +327,6 @@ bool SecureDataManager::reAuthenticate(const ByteString& passphrase, const ByteS

delete pbeKey;

decryptedKeyData += finalBlock;

// Check the magic
if (decryptedKeyData.substr(0, 3) != magic)
{
// The passphrase was incorrect
DEBUG_MSG("Incorrect passphrase supplied");

return false;
}

// And mask the key
decryptedKeyData.wipe();

Expand Down Expand Up @@ -434,8 +397,9 @@ bool SecureDataManager::decrypt(const ByteString& encrypted, ByteString& plainte
}

ByteString finalBlock;
ByteString aad;

if (!aes->decryptInit(&theKey, SymMode::CBC, IV) ||
if (!aes->decryptInit(&theKey, SymMode::GCM, IV, true, 0, aad, 16) ||
!aes->decryptUpdate(encrypted.substr(aes->getBlockSize()), plaintext) ||
!aes->decryptFinal(finalBlock))
{
Expand Down Expand Up @@ -478,8 +442,9 @@ bool SecureDataManager::encrypt(const ByteString& plaintext, ByteString& encrypt
if (!rng->generateRandom(IV, aes->getBlockSize())) return false;

ByteString finalBlock;
ByteString aad;

if (!aes->encryptInit(&theKey, SymMode::CBC, IV) ||
if (!aes->encryptInit(&theKey, SymMode::GCM, IV, true, 0, aad, 16) ||
!aes->encryptUpdate(plaintext, encrypted) ||
!aes->encryptFinal(finalBlock))
{
Expand Down
3 changes: 0 additions & 3 deletions src/lib/data_mgr/SecureDataManager.h
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Original file line number Diff line number Diff line change
Expand Up @@ -132,9 +132,6 @@ class SecureDataManager
// The masked version of the actual key
ByteString maskedKey;

// The "magic" data used to detect if a PIN was likely to be correct
ByteString magic;

// The mask; this is not a stack member but a heap member. This
// hopefully ensures that the mask ends up in a memory location
// that is not logically linked to the masked key
Expand Down