Fix another case of RK overwrite statekeeping loss

BryanJacobs · BryanJacobs · commit e8e8f399f1a6 · 2026-02-27T18:57:21.000+11:00
Fixes #50 (for real this time)
diff --git a/python_tests/ctap/test_cred_mgmt.py b/python_tests/ctap/test_cred_mgmt.py
@@ -199,3 +199,53 @@ def test_rk_overwrite(self):
 
             creds = cm.enumerate_creds(rp_id_hash=self.rp_id_hash(self.rp_id))
             self.assertEqual(1, len(creds))
+
+    def test_rk_overwrite_multiple_creds(self):
+        pin_client = self.get_high_level_client(user_interaction=FixedPinUserInteraction(self.pin))
+        self.basic_makecred_params['options'] = {
+            'rk': True
+        }
+
+        cm = self.get_credential_management()
+
+        user_id_1 = secrets.token_bytes(30)
+        user_id_2 = secrets.token_bytes(30)
+
+        res_1 = pin_client.make_credential(
+            self.get_high_level_make_cred_options(
+                ResidentKeyRequirement.REQUIRED, user_id=user_id_1
+            )
+        )
+
+        rps = cm.enumerate_rps()
+        self.assertEqual(1, len(rps))
+        creds = cm.enumerate_creds(rp_id_hash=self.rp_id_hash(self.rp_id))
+        self.assertEqual(1, len(creds))
+
+        pin_client.make_credential(
+            self.get_high_level_make_cred_options(
+                ResidentKeyRequirement.REQUIRED, user_id=user_id_2
+            )
+        )
+        rps = cm.enumerate_rps()
+        self.assertEqual(1, len(rps))
+        creds = cm.enumerate_creds(rp_id_hash=self.rp_id_hash(self.rp_id))
+        self.assertEqual(2, len(creds))
+
+        pin_client.get_assertion(self.get_high_level_assertion_opts_from_cred(cred=res_1, rp_id=self.rp_id))
+
+        rps = cm.enumerate_rps()
+        self.assertEqual(1, len(rps))
+        creds = cm.enumerate_creds(rp_id_hash=self.rp_id_hash(self.rp_id))
+        self.assertEqual(2, len(creds))
+
+        pin_client.make_credential(
+            self.get_high_level_make_cred_options(
+                ResidentKeyRequirement.REQUIRED, user_id=user_id_1
+            )
+        )
+
+        rps = cm.enumerate_rps()
+        self.assertEqual(1, len(rps))
+        creds = cm.enumerate_creds(rp_id_hash=self.rp_id_hash(self.rp_id))
+        self.assertEqual(2, len(creds))
diff --git a/src/main/java/us/q3q/fido2/FIDO2Applet.java b/src/main/java/us/q3q/fido2/FIDO2Applet.java
@@ -14,7 +14,7 @@ public final class FIDO2Applet extends Applet implements ExtendedLength {
     /**
      * The version of this applet in use
      */
-    private static final byte FIRMWARE_VERSION = 0x06;
+    private static final byte FIRMWARE_VERSION = 0x07;
 
     /**
      * The AID to which this applet should respond (ignoring any other AIDs sent to it)
@@ -1056,15 +1056,15 @@ private void makeCredential(APDU apdu, short lc, byte[] buffer) {
                     }
                 } else {
                     // Found a matching RK - overwrite it
+                    uniqueRP = residentKeys[targetRKSlot].isUniqueRP();
+
                     if (targetRKSlot < (short) (numResidentCredentials - 1)) {
                         // We need to put the credential at the end of the list so it's still the "most recent" one
                         for (short i = targetRKSlot; i < (short) (numResidentCredentials - 1); i++) {
                             residentKeys[i] = residentKeys[(short) (i + 1)];
                         }
                         targetRKSlot = (short) (numResidentCredentials - 1);
                     }
-
-                    uniqueRP = residentKeys[targetRKSlot].isUniqueRP();
                 }
 
                 byte effectiveCredBlobLen = credBlobLen;

Original file line number	Diff line number	Diff line change
`@@ -14,7 +14,7 @@ public final class FIDO2Applet extends Applet implements ExtendedLength {`
`14`	`14`	`/**`
`15`	`15`	`* The version of this applet in use`
`16`	`16`	`*/`
`17`		`- private static final byte FIRMWARE_VERSION = 0x06;`
	`17`	`+ private static final byte FIRMWARE_VERSION = 0x07;`
`18`	`18`
`19`	`19`	`/**`
`20`	`20`	`* The AID to which this applet should respond (ignoring any other AIDs sent to it)`
`@@ -1056,15 +1056,15 @@ private void makeCredential(APDU apdu, short lc, byte[] buffer) {`
`1056`	`1056`	`}`
`1057`	`1057`	`} else {`
`1058`	`1058`	`// Found a matching RK - overwrite it`
	`1059`	`+ uniqueRP = residentKeys[targetRKSlot].isUniqueRP();`
	`1060`	`+`
`1059`	`1061`	`if (targetRKSlot < (short) (numResidentCredentials - 1)) {`
`1060`	`1062`	`// We need to put the credential at the end of the list so it's still the "most recent" one`
`1061`	`1063`	`for (short i = targetRKSlot; i < (short) (numResidentCredentials - 1); i++) {`
`1062`	`1064`	`residentKeys[i] = residentKeys[(short) (i + 1)];`
`1063`	`1065`	`}`
`1064`	`1066`	`targetRKSlot = (short) (numResidentCredentials - 1);`
`1065`	`1067`	`}`
`1066`		`-`
`1067`		`- uniqueRP = residentKeys[targetRKSlot].isUniqueRP();`
`1068`	`1068`	`}`
`1069`	`1069`
`1070`	`1070`	`byte effectiveCredBlobLen = credBlobLen;`