Keymaster INT, LONG and DATE tag values are unsigned.

This CL ensures that Android Keystore framework code complies with
signedness of keymaster tags. In particular:
* INT tags are unsigned 32-bit numbers, and
* LONG and DATE tags are unsigned 64-bit numbers.

The ensure compliance, KeymasterArguments and KeyCharacteristics
classes through which Android Keystore interacts with Keymaster tags
have been modified as follows:
* ENUM and INT tags which used to be conflated are now added/queried
  via separate methods, because ENUM can remain represented as an int
  data type whereas INT is now represented as a long data type with
  permitted range being [0; 2^32).
* Methods for adding/quering LONG tags have been switched from the long
  data type to the BigInteger data type and now ensure that the value
  is in the permitted [0; 2^63).
* Methods for adding/querying DATE tags now ensure the Date value is
  in the permitted range [0; 2^63) ms since Unix epoch.
* Methods for adding tags throw an IllegalArgumentException if the tag
  type is unsuitable for the method. This is to ensure that tags with
  invalid values cannot be added through similar methods (e.g., INT tag
  added via an ENUM tag addition method invoked with a negative value).

Bug: 22008538
Change-Id: I6eefd5cbb561cc52d27de952691af4d9d5e1af1e

1 files changed, 14 insertions, 13 deletions

diff --git a/keystore/java/android/security/keystore/AndroidKeyStoreKeyPairGeneratorSpi.java b/keystore/java/android/security/keystore/AndroidKeyStoreKeyPairGeneratorSpi.java
index ff265cf..3058bd3 100644
--- a/keystore/java/android/security/keystore/AndroidKeyStoreKeyPairGeneratorSpi.java
+++ b/keystore/java/android/security/keystore/AndroidKeyStoreKeyPairGeneratorSpi.java
@@ -160,7 +160,7 @@ public abstract class AndroidKeyStoreKeyPairGeneratorSpi extends KeyPairGenerato
     private int[] mKeymasterSignaturePaddings;
     private int[] mKeymasterDigests;
 
-    private long mRSAPublicExponent;
+    private BigInteger mRSAPublicExponent;
 
     protected AndroidKeyStoreKeyPairGeneratorSpi(int keymasterAlgorithm) {
         mOriginalKeymasterAlgorithm = keymasterAlgorithm;
@@ -320,7 +320,7 @@ public abstract class AndroidKeyStoreKeyPairGeneratorSpi extends KeyPairGenerato
         mKeymasterDigests = null;
         mKeySizeBits = 0;
         mSpec = null;
-        mRSAPublicExponent = -1;
+        mRSAPublicExponent = null;
         mEncryptionAtRestRequired = false;
         mRng = null;
         mKeyStore = null;
@@ -353,12 +353,12 @@ public abstract class AndroidKeyStoreKeyPairGeneratorSpi extends KeyPairGenerato
                     throw new InvalidAlgorithmParameterException(
                             "RSA public exponent must be positive: " + publicExponent);
                 }
-                if (publicExponent.compareTo(BigInteger.valueOf(Long.MAX_VALUE)) > 0) {
+                if (publicExponent.compareTo(KeymasterArguments.UINT64_MAX_VALUE) > 0) {
                     throw new InvalidAlgorithmParameterException(
                             "Unsupported RSA public exponent: " + publicExponent
-                            + ". Only exponents <= " + Long.MAX_VALUE + " supported");
+                            + ". Maximum supported value: " + KeymasterArguments.UINT64_MAX_VALUE);
                 }
-                mRSAPublicExponent = publicExponent.longValue();
+                mRSAPublicExponent = publicExponent;
                 break;
             }
             case KeymasterDefs.KM_ALGORITHM_EC:
@@ -404,13 +404,13 @@ public abstract class AndroidKeyStoreKeyPairGeneratorSpi extends KeyPairGenerato
         }
 
         KeymasterArguments args = new KeymasterArguments();
-        args.addInt(KeymasterDefs.KM_TAG_KEY_SIZE, mKeySizeBits);
-        args.addInt(KeymasterDefs.KM_TAG_ALGORITHM, mKeymasterAlgorithm);
-        args.addInts(KeymasterDefs.KM_TAG_PURPOSE, mKeymasterPurposes);
-        args.addInts(KeymasterDefs.KM_TAG_BLOCK_MODE, mKeymasterBlockModes);
-        args.addInts(KeymasterDefs.KM_TAG_PADDING, mKeymasterEncryptionPaddings);
-        args.addInts(KeymasterDefs.KM_TAG_PADDING, mKeymasterSignaturePaddings);
-        args.addInts(KeymasterDefs.KM_TAG_DIGEST, mKeymasterDigests);
+        args.addUnsignedInt(KeymasterDefs.KM_TAG_KEY_SIZE, mKeySizeBits);
+        args.addEnum(KeymasterDefs.KM_TAG_ALGORITHM, mKeymasterAlgorithm);
+        args.addEnums(KeymasterDefs.KM_TAG_PURPOSE, mKeymasterPurposes);
+        args.addEnums(KeymasterDefs.KM_TAG_BLOCK_MODE, mKeymasterBlockModes);
+        args.addEnums(KeymasterDefs.KM_TAG_PADDING, mKeymasterEncryptionPaddings);
+        args.addEnums(KeymasterDefs.KM_TAG_PADDING, mKeymasterSignaturePaddings);
+        args.addEnums(KeymasterDefs.KM_TAG_DIGEST, mKeymasterDigests);
 
         KeymasterUtils.addUserAuthArgs(args,
                 mSpec.isUserAuthenticationRequired(),
@@ -493,7 +493,8 @@ public abstract class AndroidKeyStoreKeyPairGeneratorSpi extends KeyPairGenerato
     private void addAlgorithmSpecificParameters(KeymasterArguments keymasterArgs) {
         switch (mKeymasterAlgorithm) {
             case KeymasterDefs.KM_ALGORITHM_RSA:
-                keymasterArgs.addLong(KeymasterDefs.KM_TAG_RSA_PUBLIC_EXPONENT, mRSAPublicExponent);
+                keymasterArgs.addUnsignedLong(
+                        KeymasterDefs.KM_TAG_RSA_PUBLIC_EXPONENT, mRSAPublicExponent);
                 break;
             case KeymasterDefs.KM_ALGORITHM_EC:
                 break;