Allow constructing a PIN LockscreenCredential with mInvalidChars

KeyguardManager#setLock() (both overloads) and LockSettingsShellCommand
can try to set a PIN containing arbitrary characters.  The check for
digits-only happens in PasswordMetrics#validatePasswordMetrics().
However, due to one of my recent changes, before getting to that point,
constructing the LockscreenCredential throws IllegalArgumentException if
the PIN contains any chars outside ASCII 32–127.  This is because I had
thought this case would only be possible for PASSWORD.

As it's needed for PIN too, allow this case.

Bug: 219511761
Bug: 232900169
Bug: 243881358
Bug: 288904180
Test: atest LockscreenCredentialTest
Change-Id: Icd101f2dbb0c700a0cc5442a81c0c9ac345737b3

core/java/com/android/internal/widget/LockscreenCredential.java

@@ -64,9 +64,9 @@ public class LockscreenCredential implements Parcelable, AutoCloseable {
     // is represented as a byte array of length 0.
     private byte[] mCredential;
 
-    // This indicates that the credential is a password that used characters outside ASCII 32–127.
+    // This indicates that the credential used characters outside ASCII 32–127.
     //
-    // Such passwords were never intended to be allowed.  However, Android 10–14 had a bug where
+    // Such credentials were never intended to be allowed.  However, Android 10–14 had a bug where
     // conversion from the chars the user entered to the credential bytes used a simple truncation.
     // Thus, any 'char' whose remainder mod 256 was in the range 32–127 was accepted and was
     // equivalent to some ASCII character.  For example, ™, which is U+2122, was truncated to ASCII
@@ -102,7 +102,6 @@ public class LockscreenCredential implements Parcelable, AutoCloseable {
             // LockscreenCredential object to be constructed so that the validation logic can run,
             // even though the validation logic will ultimately reject the credential as too short.
         }
-        Preconditions.checkArgument(!hasInvalidChars || type == CREDENTIAL_TYPE_PASSWORD);
         mType = type;
         mCredential = credential;
         mHasInvalidChars = hasInvalidChars;
@@ -262,6 +261,9 @@ public class LockscreenCredential implements Parcelable, AutoCloseable {
      * short
      */
     public void validateBasicRequirements() {
+        if (mHasInvalidChars) {
+            throw new IllegalArgumentException("credential contains invalid characters");
+        }
         switch (getType()) {
             case CREDENTIAL_TYPE_PATTERN:
                 if (size() < LockPatternUtils.MIN_LOCK_PATTERN_SIZE) {
@@ -276,9 +278,6 @@ public class LockscreenCredential implements Parcelable, AutoCloseable {
                 }
                 break;
             case CREDENTIAL_TYPE_PASSWORD:
-                if (mHasInvalidChars) {
-                    throw new IllegalArgumentException("password contains invalid characters");
-                }
                 if (size() < LockPatternUtils.MIN_LOCK_PASSWORD_SIZE) {
                     throw new IllegalArgumentException("password must be at least "
                             + LockPatternUtils.MIN_LOCK_PASSWORD_SIZE + " characters long.");

core/tests/coretests/src/com/android/internal/widget/LockscreenCredentialTest.java

@@ -157,6 +157,16 @@ public class LockscreenCredentialTest {
         }
     }
 
+    @Test
+    public void testPinWithInvalidChars() {
+        LockscreenCredential pin = LockscreenCredential.createPin("\n\n\n\n");
+        assertTrue(pin.hasInvalidChars());
+        try {
+            pin.validateBasicRequirements();
+            fail("should not be able to set PIN with invalid chars");
+        } catch (IllegalArgumentException expected) { }
+    }
+
     @Test
     public void testSanitize() {
         LockscreenCredential password = LockscreenCredential.createPassword("password");