From be10891cab6ef8942cdeb6fd36920804199161a5 Mon Sep 17 00:00:00 2001
From: Allen Webb <allenwebb@google.com>
Date: Thu, 29 Mar 2018 09:50:45 -0700
Subject: [PATCH] keystore: Change superclass of
 UserPresenceUnavailableException.

Also add additional comments to isTrustedUserPresenceRequired().

Test: m -j KeystoreTests && adb install -r
out/target/product/${TARGET_PRODUCT}/data/app/KeystoreTests/KeystoreTests.apk
    adb shell am instrument

Bug: 73392697
Bug: 76462141
Change-Id: Iabcc331adda53e2a5cad5ead6002dfbc29188da2
Signed-off-by: Allen Webb <allenwebb@google.com>
---
 api/current.txt                                               | 2 +-
 keystore/java/android/security/keystore/KeyProtection.java    | 3 +++
 .../security/keystore/UserPresenceUnavailableException.java   | 4 ++--
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/api/current.txt b/api/current.txt
index d0eee5c1a438c..5471a5614bf52 100644
--- a/api/current.txt
+++ b/api/current.txt
@@ -38717,7 +38717,7 @@ package android.security.keystore {
     ctor public UserNotAuthenticatedException(java.lang.String, java.lang.Throwable);
   }
 
-  public class UserPresenceUnavailableException extends java.security.InvalidAlgorithmParameterException {
+  public class UserPresenceUnavailableException extends java.security.InvalidKeyException {
     ctor public UserPresenceUnavailableException();
     ctor public UserPresenceUnavailableException(java.lang.String);
     ctor public UserPresenceUnavailableException(java.lang.String, java.lang.Throwable);
diff --git a/keystore/java/android/security/keystore/KeyProtection.java b/keystore/java/android/security/keystore/KeyProtection.java
index cc7870ce1889d..181a46aafcb50 100644
--- a/keystore/java/android/security/keystore/KeyProtection.java
+++ b/keystore/java/android/security/keystore/KeyProtection.java
@@ -445,6 +445,9 @@ public final class KeyProtection implements ProtectionParameter, UserAuthArgs {
     /**
      * Returns {@code true} if the key is authorized to be used only if a test of user presence has
      * been performed between the {@code Signature.initSign()} and {@code Signature.sign()} calls.
+     * It requires that the KeyStore implementation have a direct way to validate the user presence
+     * for example a KeyStore hardware backed strongbox can use a button press that is observable
+     * in hardware.
      */
     public boolean isTrustedUserPresenceRequired() {
         return mTrustedUserPresenceRequired;
diff --git a/keystore/java/android/security/keystore/UserPresenceUnavailableException.java b/keystore/java/android/security/keystore/UserPresenceUnavailableException.java
index cf4099efc6695..1b053a5c857ea 100644
--- a/keystore/java/android/security/keystore/UserPresenceUnavailableException.java
+++ b/keystore/java/android/security/keystore/UserPresenceUnavailableException.java
@@ -16,13 +16,13 @@
 
 package android.security.keystore;
 
-import java.security.InvalidAlgorithmParameterException;
+import java.security.InvalidKeyException;
 
 /**
  * Indicates the condition that a proof of user-presence was
  * requested but this proof was not presented.
  */
-public class UserPresenceUnavailableException extends InvalidAlgorithmParameterException {
+public class UserPresenceUnavailableException extends InvalidKeyException {
     /**
      * Constructs a {@code UserPresenceUnavailableException} without a detail message or cause.
      */