Passkeys: Set BE and BS flags to true (#13042)

Passkeys: Set BE flag to true

---------

Co-authored-by: varjolintu <sami.vanttinen@ahmala.org>

src/browser/BrowserPasskeys.cpp

@@ -1,5 +1,5 @@
 /*
- *  Copyright (C) 2025 KeePassXC Team <team@keepassxc.org>
+ *  Copyright (C) 2026 KeePassXC Team <team@keepassxc.org>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -125,14 +125,16 @@ PublicKeyCredential BrowserPasskeys::buildRegisterPublicKeyCredential(const QJso
 QJsonObject BrowserPasskeys::buildGetPublicKeyCredential(const QJsonObject& assertionOptions,
                                                          const QString& credentialId,
                                                          const QString& userHandle,
-                                                         const QString& privateKeyPem)
+                                                         const QString& privateKeyPem,
+                                                         const bool beFlag,
+                                                         const bool bsFlag)
 {
     if (!passkeyUtils()->checkCredentialAssertionOptions(assertionOptions)) {
         return {};
     }
 
-    const auto authenticatorData =
+    const auto authenticatorData = buildAuthenticatorData(
-        buildAuthenticatorData(assertionOptions["rpId"].toString(), assertionOptions["extensions"].toString());
+        assertionOptions["rpId"].toString(), assertionOptions["extensions"].toString(), beFlag, bsFlag);
     const auto clientDataJson = assertionOptions["clientDataJson"].toString();
     const auto clientDataArray = clientDataJson.toUtf8();
 
@@ -171,8 +173,12 @@ QByteArray BrowserPasskeys::buildAttestationObject(const QJsonObject& credential
     result.append(rpIdHash);
 
     // Use default flags
-    const auto flags = setFlagsFromJson(QJsonObject(
+    const auto flags = setFlagsFromJson(QJsonObject({{"ED", !extensions.isEmpty()},
-        {{"ED", !extensions.isEmpty()}, {"AT", true}, {"BS", false}, {"BE", false}, {"UV", true}, {"UP", true}}));
+                                                     {"AT", true},
+                                                     {"BS", DEFAULT_BS_FLAG},
+                                                     {"BE", DEFAULT_BE_FLAG},
+                                                     {"UV", true},
+                                                     {"UP", true}}));
     result.append(flags);
 
     // Signature counter (not supported, always 0
@@ -204,7 +210,10 @@ QByteArray BrowserPasskeys::buildAttestationObject(const QJsonObject& credential
 }
 
 // Build a short version of the attestation object for webauthn.get
-QByteArray BrowserPasskeys::buildAuthenticatorData(const QString& rpId, const QString& extensions)
+QByteArray BrowserPasskeys::buildAuthenticatorData(const QString& rpId,
+                                                   const QString& extensions,
+                                                   const bool beFlag,
+                                                   const bool bsFlag)
 {
     QByteArray result;
 
@@ -212,7 +221,7 @@ QByteArray BrowserPasskeys::buildAuthenticatorData(const QString& rpId, const QS
     result.append(rpIdHash);
 
     const auto flags = setFlagsFromJson(QJsonObject(
-        {{"ED", !extensions.isEmpty()}, {"AT", false}, {"BS", false}, {"BE", false}, {"UV", true}, {"UP", true}}));
+        {{"ED", !extensions.isEmpty()}, {"AT", false}, {"BS", bsFlag}, {"BE", beFlag}, {"UV", true}, {"UP", true}}));
     result.append(flags);
 
     // Signature counter (not supported, always 0

src/browser/BrowserPasskeys.h

@@ -1,5 +1,5 @@
 /*
- *  Copyright (C) 2024 KeePassXC Team <team@keepassxc.org>
+ *  Copyright (C) 2026 KeePassXC Team <team@keepassxc.org>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -25,6 +25,8 @@
 #include <botan/asn1_obj.h>
 #include <botan/bigint.h>
 
+#define DEFAULT_BE_FLAG true
+#define DEFAULT_BS_FLAG true
 #define ID_BYTES 32
 #define HASH_BYTES 32
 #define RSA_BITS 2048
@@ -87,7 +89,9 @@ public:
     QJsonObject buildGetPublicKeyCredential(const QJsonObject& assertionOptions,
                                             const QString& credentialId,
                                             const QString& userHandle,
-                                            const QString& privateKeyPem);
+                                            const QString& privateKeyPem,
+                                            const bool beFlag = DEFAULT_BE_FLAG,
+                                            const bool bsFlag = DEFAULT_BE_FLAG);
 
     static const QString AAGUID;
 
@@ -113,7 +117,10 @@ private:
                                       const QString& credentialId,
                                       const QByteArray& cborEncodedPublicKey,
                                       const TestingVariables& testingVariables = {});
-    QByteArray buildAuthenticatorData(const QString& rpId, const QString& extensions);
+    QByteArray buildAuthenticatorData(const QString& rpId,
+                                      const QString& extensions,
+                                      const bool beFlag = DEFAULT_BE_FLAG,
+                                      const bool bsFlag = DEFAULT_BE_FLAG);
     AttestationKeyPair buildCredentialPrivateKey(int alg, const TestingVariables& testingVariables = {});
     QByteArray
     buildSignature(const QByteArray& authenticatorData, const QByteArray& clientData, const QString& privateKeyPem);

src/browser/BrowserService.cpp

@@ -1,5 +1,5 @@
 /*
- *  Copyright (C) 2025 KeePassXC Team <team@keepassxc.org>
+ *  Copyright (C) 2026 KeePassXC Team <team@keepassxc.org>
  *  Copyright (C) 2017 Sami Vänttinen <sami.vanttinen@protonmail.com>
  *  Copyright (C) 2013 Francois Ferrand
  *
@@ -775,8 +775,16 @@ QJsonObject BrowserService::showPasskeysAuthenticationPrompt(const QJsonObject&
         const auto credentialId = passkeyUtils()->getCredentialIdFromEntry(selectedEntry);
         const auto userHandle = selectedEntry->attributes()->value(EntryAttributes::KPEX_PASSKEY_USER_HANDLE);
 
-        auto publicKeyCredential =
+        // Get BE and BS flags if present
-            browserPasskeys()->buildGetPublicKeyCredential(assertionOptions, credentialId, userHandle, privateKeyPem);
+        const auto beFlag = selectedEntry->attributes()->hasKey(EntryAttributes::KPEX_PASSKEY_FLAG_BE)
+                                ? selectedEntry->attributes()->value(EntryAttributes::KPEX_PASSKEY_FLAG_BE) == TRUE_STR
+                                : DEFAULT_BE_FLAG;
+        const auto bsFlag = selectedEntry->attributes()->hasKey(EntryAttributes::KPEX_PASSKEY_FLAG_BS)
+                                ? selectedEntry->attributes()->value(EntryAttributes::KPEX_PASSKEY_FLAG_BS) == TRUE_STR
+                                : DEFAULT_BS_FLAG;
+
+        auto publicKeyCredential = browserPasskeys()->buildGetPublicKeyCredential(
+            assertionOptions, credentialId, userHandle, privateKeyPem, beFlag, bsFlag);
         if (publicKeyCredential.isEmpty()) {
             return getPasskeyError(ERROR_PASSKEYS_UNKNOWN_ERROR);
         }
@@ -856,6 +864,8 @@ void BrowserService::addPasskeyToEntry(Entry* entry,
     entry->attributes()->set(EntryAttributes::KPEX_PASSKEY_PRIVATE_KEY_PEM, privateKey, true);
     entry->attributes()->set(EntryAttributes::KPEX_PASSKEY_RELYING_PARTY, rpId);
     entry->attributes()->set(EntryAttributes::KPEX_PASSKEY_USER_HANDLE, userHandle, true);
+    entry->attributes()->set(EntryAttributes::KPEX_PASSKEY_FLAG_BE, TRUE_STR);
+    entry->attributes()->set(EntryAttributes::KPEX_PASSKEY_FLAG_BS, TRUE_STR);
     entry->addTag(tr("Passkey"));
 
     entry->endUpdate();

src/core/EntryAttributes.cpp

@@ -1,5 +1,5 @@
 /*
- *  Copyright (C) 2024 KeePassXC Team <team@keepassxc.org>
+ *  Copyright (C) 2026 KeePassXC Team <team@keepassxc.org>
  *  Copyright (C) 2012 Felix Geyer <debfx@fobos.de>
  *
  *  This program is free software: you can redistribute it and/or modify
@@ -46,6 +46,8 @@ const QString EntryAttributes::KPEX_PASSKEY_RELYING_PARTY = QStringLiteral("KPEX
 const QString EntryAttributes::KPEX_PASSKEY_USER_HANDLE = QStringLiteral("KPEX_PASSKEY_USER_HANDLE");
 const QString EntryAttributes::KPEX_PASSKEY_PRIVATE_KEY_START = QStringLiteral("-----BEGIN PRIVATE KEY-----");
 const QString EntryAttributes::KPEX_PASSKEY_PRIVATE_KEY_END = QStringLiteral("-----END PRIVATE KEY-----");
+const QString EntryAttributes::KPEX_PASSKEY_FLAG_BE = QStringLiteral("KPEX_PASSKEY_FLAG_BE");
+const QString EntryAttributes::KPEX_PASSKEY_FLAG_BS = QStringLiteral("KPEX_PASSKEY_FLAG_BS");
 
 // For compatibility with StrongBox
 const QString EntryAttributes::KPEX_PASSKEY_GENERATED_USER_ID = QStringLiteral("KPEX_PASSKEY_GENERATED_USER_ID");

src/core/EntryAttributes.h

@@ -1,5 +1,5 @@
 /*
- *  Copyright (C) 2024 KeePassXC Team <team@keepassxc.org>
+ *  Copyright (C) 2026 KeePassXC Team <team@keepassxc.org>
  *  Copyright (C) 2012 Felix Geyer <debfx@fobos.de>
  *
  *  This program is free software: you can redistribute it and/or modify
@@ -75,6 +75,8 @@ public:
     static const QString KPEX_PASSKEY_USER_HANDLE;
     static const QString KPEX_PASSKEY_PRIVATE_KEY_START;
     static const QString KPEX_PASSKEY_PRIVATE_KEY_END;
+    static const QString KPEX_PASSKEY_FLAG_BE;
+    static const QString KPEX_PASSKEY_FLAG_BS;
 
     static bool isDefaultAttribute(const QString& key);
     static bool isPasskeyAttribute(const QString& key);

tests/TestPasskeys.cpp

@@ -1,5 +1,5 @@
 /*
- *  Copyright (C) 2025 KeePassXC Team <team@keepassxc.org>
+ *  Copyright (C) 2026 KeePassXC Team <team@keepassxc.org>
  *
  *  This program is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -77,7 +77,7 @@ const QString PublicKeyCredential = R"(
         "id": "yrzFJ5lwcpTwYMOdXSmxF5b5cYQlqBMzbbU_d-oFLO8",
         "rawId": "cabcc52799707294f060c39d5d29b11796f9718425a813336db53f77ea052cef",
         "response": {
-            "attestationObject": "o2NmbXRkbm9uZWdhdHRTdG10oGhhdXRoRGF0YVikdKbqkhPJnC90siSSsyDPQCYqlMGpUKA5fyklC2CEHvBFAAAAAP2xQbJdhEQ-ijVGmMIFpQIAIMq8xSeZcHKU8GDDnV0psReW-XGEJagTM221P3fqBSzvpQECAyYgASFYIHK1iVimeR02UYipyiEKrKhhfhJRMew8EbDWGKtMZ2wUIlggbtZ70X11SLx17QFDWVAR3_qqk5OqrRS--Whc7hyw9YU",
+            "attestationObject": "o2NmbXRkbm9uZWdhdHRTdG10oGhhdXRoRGF0YVikdKbqkhPJnC90siSSsyDPQCYqlMGpUKA5fyklC2CEHvBdAAAAAP2xQbJdhEQ-ijVGmMIFpQIAIMq8xSeZcHKU8GDDnV0psReW-XGEJagTM221P3fqBSzvpQECAyYgASFYIHK1iVimeR02UYipyiEKrKhhfhJRMew8EbDWGKtMZ2wUIlggbtZ70X11SLx17QFDWVAR3_qqk5OqrRS--Whc7hyw9YU",
             "clientDataJSON": "eyJ0eXBlIjoid2ViYXV0aG4uY3JlYXRlIiwiY2hhbGxlbmdlIjoibFZlSHpWeFdzcjhNUXhNa1pGMHRpNkZYaGRnTWxqcUt6Z0EtcV96azJNbmlpM2VKNDdWRjk3c3FVb1lrdFZDODVXQVoxdUlBU20tYV9sREZad3NMZnciLCJvcmlnaW4iOiJodHRwczovL3dlYmF1dGhuLmlvIiwiY3Jvc3NPcmlnaW4iOmZhbHNlfQ"
         },
         "type": "public-key"
@@ -185,6 +185,8 @@ void TestPasskeys::testDecodeResponseData()
     QCOMPARE(authData["rpIdHash"].toString(), QString("dKbqkhPJnC90siSSsyDPQCYqlMGpUKA5fyklC2CEHvA"));
     QCOMPARE(flags["AT"], true);
     QCOMPARE(flags["UP"], true);
+    QCOMPARE(flags["BE"], true);
+    QCOMPARE(flags["BS"], true);
     QCOMPARE(publicKey["1"], 2);
     QCOMPARE(publicKey["3"], -7);
     QCOMPARE(publicKey["-1"], 1);
@@ -285,13 +287,18 @@ void TestPasskeys::testCreatingAttestationObjectWithEC()
         result,
         QString("\xA3"
                 "cfmtdnonegattStmt\xA0hauthDataX\xA4t\xA6\xEA\x92\x13\xC9\x9C/t\xB2$\x92\xB3 \xCF@&*\x94\xC1\xA9P\xA0"
-                "9\x7F)%\x0B`\x84\x1E\xF0"
+                "9\x7F)%\x0B`\x84\x1E\xF0]\x00\x00\x00\x00\xFD\xB1"
-                "E\x00\x00\x00\x01\x01\x02\x03\x04\x05\x06\x07\b\x01\x02\x03\x04\x05\x06\x07\b\x00 \x8B\xB0\xCA"
+                "A\xB2]\x84"
-                "6\x17\xD6\xDE\x01\x11|\xEA\x94\r\xA0R\xC0\x80_\xF3r\xFBr\xB5\x02\x03:"
+                "D>\x8A"
-                "\xBAr\x0Fi\x81\xFE\xA5\x01\x02\x03& \x01!X "
+                "5F\x98\xC2\x05\xA5\x02\x00 \xCA\xBC\xC5'\x99pr\x94\xF0`\xC3\x9D])\xB1\x17\x96\xF9q\x84%\xA8\x13"
-                "e\xE2\xF2\x1F:cq\xD3G\xEA\xE0\xF7\x1F\xCF\xFA\\\xABO\xF6\x86\x88\x80\t\xAE\x81\x8BT\xB2\x9B\x15\x85~"
+                "3m\xB5?w\xEA\x05,\xEF\xA5\x01\x02\x03& \x01!X \x06\xEC\xAF"
-                "\"X \\\x8E\x1E@\xDB\x97T-\xF8\x9B\xB0\xAD"
+                "4[b\x91"
-                "5\xDC\x12^\xC3\x95\x05\xC6\xDF^\x03\xCB\xB4Q\x91\xFF|\xDB\x94\xB7"));
+                "am\x19Y\x03\xA6P*\xCA"
+                "1\xC4\x95\xA8i\xE5\xF0\x87\xE5\xD4\xB8"
+                "2\xCD\b\x85\xDD\"X \xE2\xEE\x7F\xE9\x0F\x0E\xE9\x1D\x07\x83J\x03\t\xDB"
+                "B$\xB1\x0B\xD3%\xFF\x18"
+                "2\xE1S\x99\xB7\x1D"
+                "B\x04\xE7\x83"));
 
     // Double check that the result can be decoded
     BrowserCbor browserCbor;
@@ -312,6 +319,8 @@ void TestPasskeys::testCreatingAttestationObjectWithEC()
     QCOMPARE(authData["rpIdHash"].toString(), QString("dKbqkhPJnC90siSSsyDPQCYqlMGpUKA5fyklC2CEHvA"));
     QCOMPARE(flags["AT"], true);
     QCOMPARE(flags["UP"], true);
+    QCOMPARE(flags["BE"], true);
+    QCOMPARE(flags["BS"], true);
     QCOMPARE(publicKey["1"], WebAuthnCoseKeyType::EC2);
     QCOMPARE(publicKey["3"], WebAuthnAlgorithms::ES256);
     QCOMPARE(publicKey["-1"], 1);
@@ -368,6 +377,8 @@ void TestPasskeys::testCreatingAttestationObjectWithRSA()
     QCOMPARE(authData["rpIdHash"].toString(), QString("dKbqkhPJnC90siSSsyDPQCYqlMGpUKA5fyklC2CEHvA"));
     QCOMPARE(flags["AT"], true);
     QCOMPARE(flags["UP"], true);
+    QCOMPARE(flags["BE"], true);
+    QCOMPARE(flags["BS"], true);
     QCOMPARE(publicKey["1"], WebAuthnCoseKeyType::RSA);
     QCOMPARE(publicKey["3"], WebAuthnAlgorithms::RS256);
     QCOMPARE(publicKey["-1"], predefinedModulus);
@@ -438,14 +449,14 @@ void TestPasskeys::testGet()
     QCOMPARE(publicKeyCredential["id"].toString(), id);
 
     auto response = publicKeyCredential["response"].toObject();
-    QCOMPARE(response["authenticatorData"].toString(), QString("dKbqkhPJnC90siSSsyDPQCYqlMGpUKA5fyklC2CEHvAFAAAAAA"));
+    QCOMPARE(response["authenticatorData"].toString(), QString("dKbqkhPJnC90siSSsyDPQCYqlMGpUKA5fyklC2CEHvAdAAAAAA"));
     QCOMPARE(response["clientDataJSON"].toString(),
              QString("eyJ0eXBlIjoid2ViYXV0aG4uZ2V0IiwiY2hhbGxlbmdlIjoiOXozNnZUZlFUTDk1TGY3V25aZ3l0ZTdvaEdlRi1YUmlMeGtML"
                      "Ux1R1Uxem9wUm1NSVVBMUxWd3pHcHlJbTFmT0JuMVFuUmEwUUgyN0FEQWFKR0h5c1EiLCJvcmlnaW4iOiJodHRwczovL3dlYm"
                      "F1dGhuLmlvIiwiY3Jvc3NPcmlnaW4iOmZhbHNlfQ"));
     QCOMPARE(
         response["signature"].toString(),
-        QString("MEYCIQCpbDaYJ4b2ofqWBxfRNbH3XCpsyao7Iui5lVuJRU9HIQIhAPl5moNZgJu5zmurkKK_P900Ct6wd3ahVIqCEqTeeRdE"));
+        QString("MEUCIQCvg3nXO2fiNK9ockxscgPtoM9_u6ERaW2-F1L99YasOAIgNhYOjPJyKJ-W8roV531kC59ss1USas7jy8TfRnbJLtg"));
 
     auto clientDataJson = response["clientDataJSON"].toString();
     auto clientDataByteArray = browserMessageBuilder()->getArrayFromBase64(clientDataJson);