Take PIN ownership to minimze memory copy-s

followup WE2-479 Signed-off-by: Raul Metsma <[email protected]>
metsma · Aug 6, 2024 · 11cc03f · 11cc03f
1 parent 0fbaab4
commit 11cc03f
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Showing 3 changed files with 9 additions and 23 deletions.
diff --git a/lib/libelectronic-id b/lib/libelectronic-id
diff --git a/src/controller/command-handlers/authenticate.cpp b/src/controller/command-handlers/authenticate.cpp
@@ -56,7 +56,7 @@ QVariantMap createAuthenticationToken(const QString& signatureAlgorithm,
 }
 
 QByteArray createSignature(const QString& origin, const QString& challengeNonce,
-                           const ElectronicID& eid, const pcsc_cpp::byte_vector& pin)
+                           const ElectronicID& eid, pcsc_cpp::byte_vector&& pin)
 {
     static const std::map<JsonWebSignatureAlgorithm, QCryptographicHash::Algorithm>
         SIGNATURE_ALGO_TO_HASH {
@@ -85,7 +85,7 @@ QByteArray createSignature(const QString& origin, const QString& challengeNonce,
     const pcsc_cpp::byte_vector hashToBeSigned {hashToBeSignedQBytearray.cbegin(),
                                                 hashToBeSignedQBytearray.cend()};
 
-    const auto signature = eid.signWithAuthKey(pin, hashToBeSigned);
+    const auto signature = eid.signWithAuthKey(std::move(pin), hashToBeSigned);
 
     return QByteArray::fromRawData(reinterpret_cast<const char*>(signature.data()),
                                    int(signature.size()))
@@ -122,17 +122,10 @@ QVariantMap Authenticate::onConfirm(WebEidUI* window,
     const auto signatureAlgorithm =
         QString::fromStdString(cardCertAndPin.cardInfo->eid().authSignatureAlgorithm());
 
-    auto pin = getPin(cardCertAndPin.cardInfo->eid(), window);
-
     try {
+        auto pin = getPin(cardCertAndPin.cardInfo->eid(), window);
         const auto signature =
-            createSignature(origin.url(), challengeNonce, cardCertAndPin.cardInfo->eid(), pin);
-
-        // Erase the PIN memory.
-        // TODO: Use a scope guard. Verify that the buffers are actually zeroed and no copies
-        // remain.
-        std::fill(pin.begin(), pin.end(), '\0');
-
+            createSignature(origin.url(), challengeNonce, cardCertAndPin.cardInfo->eid(), std::move(pin));
         return createAuthenticationToken(signatureAlgorithm, cardCertAndPin.certificateBytesInDer,
                                          signature);
 

diff --git a/src/controller/command-handlers/sign.cpp b/src/controller/command-handlers/sign.cpp
@@ -30,11 +30,11 @@ using namespace electronic_id;
 namespace
 {
 
-QPair<QString, QVariantMap> signHash(const ElectronicID& eid, const pcsc_cpp::byte_vector& pin,
+QPair<QString, QVariantMap> signHash(const ElectronicID& eid, pcsc_cpp::byte_vector&& pin,
                                      const QByteArray& docHash, const HashAlgorithm hashAlgo)
 {
     const auto hashBytes = pcsc_cpp::byte_vector {docHash.begin(), docHash.end()};
-    const auto signature = eid.signWithSigningKey(pin, hashBytes, hashAlgo);
+    const auto signature = eid.signWithSigningKey(std::move(pin), hashBytes, hashAlgo);
 
     const auto signatureBase64 =
         QByteArray::fromRawData(reinterpret_cast<const char*>(signature.first.data()),
@@ -95,16 +95,9 @@ void Sign::emitCertificatesReady(const std::vector<CardCertificateAndPinInfo>& c
 
 QVariantMap Sign::onConfirm(WebEidUI* window, const CardCertificateAndPinInfo& cardCertAndPin)
 {
-    auto pin = getPin(cardCertAndPin.cardInfo->eid(), window);
-
     try {
-        const auto signature = signHash(cardCertAndPin.cardInfo->eid(), pin, docHash, hashAlgo);
-
-        // Erase PIN memory.
-        // TODO: Use a scope guard. Verify that the buffers are actually zeroed
-        // and no copies remain.
-        std::fill(pin.begin(), pin.end(), '\0');
-
+        auto pin = getPin(cardCertAndPin.cardInfo->eid(), window);
+        const auto signature = signHash(cardCertAndPin.cardInfo->eid(), std::move(pin), docHash, hashAlgo);
         return {{QStringLiteral("signature"), signature.first},
                 {QStringLiteral("signatureAlgorithm"), signature.second}};