Merge "Revert^2 "MGF1 Digest setter: Handle case of flag off"" into main am: 9fa4063071

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/2854787

Change-Id: Ib7499cf79580cbac70e0cef4eb893ac5acd1e3d9
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

6 files changed, 76 insertions, 12 deletions

diff --git a/core/api/current.txt b/core/api/current.txt
index b44ff6c8e0ea..c600df19a379 100644
--- a/core/api/current.txt
+++ b/core/api/current.txt
@@ -39579,7 +39579,7 @@ package android.security.keystore {
     method @Nullable public java.util.Date getKeyValidityStart();
     method @NonNull public String getKeystoreAlias();
     method public int getMaxUsageCount();
-    method @FlaggedApi("MGF1_DIGEST_SETTER") @NonNull public java.util.Set<java.lang.String> getMgf1Digests();
+    method @FlaggedApi("android.security.mgf1_digest_setter") @NonNull public java.util.Set<java.lang.String> getMgf1Digests();
     method public int getPurposes();
     method @NonNull public String[] getSignaturePaddings();
     method public int getUserAuthenticationType();
@@ -39587,7 +39587,7 @@ package android.security.keystore {
     method public boolean isDevicePropertiesAttestationIncluded();
     method @NonNull public boolean isDigestsSpecified();
     method public boolean isInvalidatedByBiometricEnrollment();
-    method @FlaggedApi("MGF1_DIGEST_SETTER") @NonNull public boolean isMgf1DigestsSpecified();
+    method @FlaggedApi("android.security.mgf1_digest_setter") @NonNull public boolean isMgf1DigestsSpecified();
     method public boolean isRandomizedEncryptionRequired();
     method public boolean isStrongBoxBacked();
     method public boolean isUnlockedDeviceRequired();
@@ -39619,7 +39619,7 @@ package android.security.keystore {
     method @NonNull public android.security.keystore.KeyGenParameterSpec.Builder setKeyValidityForOriginationEnd(java.util.Date);
     method @NonNull public android.security.keystore.KeyGenParameterSpec.Builder setKeyValidityStart(java.util.Date);
     method @NonNull public android.security.keystore.KeyGenParameterSpec.Builder setMaxUsageCount(int);
-    method @FlaggedApi("MGF1_DIGEST_SETTER") @NonNull public android.security.keystore.KeyGenParameterSpec.Builder setMgf1Digests(@NonNull java.lang.String...);
+    method @FlaggedApi("android.security.mgf1_digest_setter") @NonNull public android.security.keystore.KeyGenParameterSpec.Builder setMgf1Digests(@NonNull java.lang.String...);
     method @NonNull public android.security.keystore.KeyGenParameterSpec.Builder setRandomizedEncryptionRequired(boolean);
     method @NonNull public android.security.keystore.KeyGenParameterSpec.Builder setSignaturePaddings(java.lang.String...);
     method @NonNull public android.security.keystore.KeyGenParameterSpec.Builder setUnlockedDeviceRequired(boolean);
@@ -39724,14 +39724,14 @@ package android.security.keystore {
     method @Nullable public java.util.Date getKeyValidityForOriginationEnd();
     method @Nullable public java.util.Date getKeyValidityStart();
     method public int getMaxUsageCount();
-    method @FlaggedApi("MGF1_DIGEST_SETTER") @NonNull public java.util.Set<java.lang.String> getMgf1Digests();
+    method @FlaggedApi("android.security.mgf1_digest_setter") @NonNull public java.util.Set<java.lang.String> getMgf1Digests();
     method public int getPurposes();
     method @NonNull public String[] getSignaturePaddings();
     method public int getUserAuthenticationType();
     method public int getUserAuthenticationValidityDurationSeconds();
     method public boolean isDigestsSpecified();
     method public boolean isInvalidatedByBiometricEnrollment();
-    method @FlaggedApi("MGF1_DIGEST_SETTER") @NonNull public boolean isMgf1DigestsSpecified();
+    method @FlaggedApi("android.security.mgf1_digest_setter") @NonNull public boolean isMgf1DigestsSpecified();
     method public boolean isRandomizedEncryptionRequired();
     method public boolean isUnlockedDeviceRequired();
     method public boolean isUserAuthenticationRequired();
@@ -39753,7 +39753,7 @@ package android.security.keystore {
     method @NonNull public android.security.keystore.KeyProtection.Builder setKeyValidityForOriginationEnd(java.util.Date);
     method @NonNull public android.security.keystore.KeyProtection.Builder setKeyValidityStart(java.util.Date);
     method @NonNull public android.security.keystore.KeyProtection.Builder setMaxUsageCount(int);
-    method @FlaggedApi("MGF1_DIGEST_SETTER") @NonNull public android.security.keystore.KeyProtection.Builder setMgf1Digests(@Nullable java.lang.String...);
+    method @FlaggedApi("android.security.mgf1_digest_setter") @NonNull public android.security.keystore.KeyProtection.Builder setMgf1Digests(@Nullable java.lang.String...);
     method @NonNull public android.security.keystore.KeyProtection.Builder setRandomizedEncryptionRequired(boolean);
     method @NonNull public android.security.keystore.KeyProtection.Builder setSignaturePaddings(java.lang.String...);
     method @NonNull public android.security.keystore.KeyProtection.Builder setUnlockedDeviceRequired(boolean);
diff --git a/core/java/android/security/flags.aconfig b/core/java/android/security/flags.aconfig
index ef1d682ee786..17f750410316 100644
--- a/core/java/android/security/flags.aconfig
+++ b/core/java/android/security/flags.aconfig
@@ -15,6 +15,13 @@ flag {
 }
 
 flag {
+    name: "mgf1_digest_setter"
+    namespace: "hardware_backed_security"
+    description: "Feature flag for mgf1 digest setter in key generation and import parameters."
+    bug: "308378912"
+}
+
+flag {
     name: "fix_unlocked_device_required_keys_v2"
     namespace: "hardware_backed_security"
     description: "Fix bugs in behavior of UnlockedDeviceRequired keystore keys"
diff --git a/keystore/java/android/security/keystore/KeyGenParameterSpec.java b/keystore/java/android/security/keystore/KeyGenParameterSpec.java
index 231fa4837441..4982f3732089 100644
--- a/keystore/java/android/security/keystore/KeyGenParameterSpec.java
+++ b/keystore/java/android/security/keystore/KeyGenParameterSpec.java
@@ -618,7 +618,7 @@ public final class KeyGenParameterSpec implements AlgorithmParameterSpec, UserAu
      * @see #isMgf1DigestsSpecified()
      */
     @NonNull
-    @FlaggedApi("MGF1_DIGEST_SETTER")
+    @FlaggedApi(android.security.Flags.FLAG_MGF1_DIGEST_SETTER)
     public @KeyProperties.DigestEnum Set<String> getMgf1Digests() {
         if (mMgf1Digests.isEmpty()) {
             throw new IllegalStateException("Mask generation function (MGF) not specified");
@@ -633,7 +633,7 @@ public final class KeyGenParameterSpec implements AlgorithmParameterSpec, UserAu
      * @see #getMgf1Digests()
      */
     @NonNull
-    @FlaggedApi("MGF1_DIGEST_SETTER")
+    @FlaggedApi(android.security.Flags.FLAG_MGF1_DIGEST_SETTER)
     public boolean isMgf1DigestsSpecified() {
         return !mMgf1Digests.isEmpty();
     }
@@ -1292,7 +1292,7 @@ public final class KeyGenParameterSpec implements AlgorithmParameterSpec, UserAu
          * <p>See {@link KeyProperties}.{@code DIGEST} constants.
          */
         @NonNull
-        @FlaggedApi("MGF1_DIGEST_SETTER")
+        @FlaggedApi(android.security.Flags.FLAG_MGF1_DIGEST_SETTER)
         public Builder setMgf1Digests(@NonNull @KeyProperties.DigestEnum String... mgf1Digests) {
             mMgf1Digests = Set.of(mgf1Digests);
             return this;
diff --git a/keystore/java/android/security/keystore/KeyProtection.java b/keystore/java/android/security/keystore/KeyProtection.java
index c1e3bab5d37c..7b6b2d142f95 100644
--- a/keystore/java/android/security/keystore/KeyProtection.java
+++ b/keystore/java/android/security/keystore/KeyProtection.java
@@ -401,7 +401,7 @@ public final class KeyProtection implements ProtectionParameter, UserAuthArgs {
      * @see #isMgf1DigestsSpecified()
      */
     @NonNull
-    @FlaggedApi("MGF1_DIGEST_SETTER")
+    @FlaggedApi(android.security.Flags.FLAG_MGF1_DIGEST_SETTER)
     public @KeyProperties.DigestEnum Set<String> getMgf1Digests() {
         if (mMgf1Digests.isEmpty()) {
             throw new IllegalStateException("Mask generation function (MGF) not specified");
@@ -416,7 +416,7 @@ public final class KeyProtection implements ProtectionParameter, UserAuthArgs {
      * @see #getMgf1Digests()
      */
     @NonNull
-    @FlaggedApi("MGF1_DIGEST_SETTER")
+    @FlaggedApi(android.security.Flags.FLAG_MGF1_DIGEST_SETTER)
     public boolean isMgf1DigestsSpecified() {
         return !mMgf1Digests.isEmpty();
     }
@@ -799,7 +799,7 @@ public final class KeyProtection implements ProtectionParameter, UserAuthArgs {
          * <p>See {@link KeyProperties}.{@code DIGEST} constants.
          */
         @NonNull
-        @FlaggedApi("MGF1_DIGEST_SETTER")
+        @FlaggedApi(android.security.Flags.FLAG_MGF1_DIGEST_SETTER)
         public Builder setMgf1Digests(@Nullable @KeyProperties.DigestEnum String... mgf1Digests) {
             mMgf1Digests = Set.of(mgf1Digests);
             return this;
diff --git a/keystore/java/android/security/keystore2/AndroidKeyStoreKeyPairGeneratorSpi.java b/keystore/java/android/security/keystore2/AndroidKeyStoreKeyPairGeneratorSpi.java
index ed4b485f3927..9c05a3a768a0 100644
--- a/keystore/java/android/security/keystore2/AndroidKeyStoreKeyPairGeneratorSpi.java
+++ b/keystore/java/android/security/keystore2/AndroidKeyStoreKeyPairGeneratorSpi.java
@@ -28,6 +28,7 @@ import android.hardware.security.keymint.SecurityLevel;
 import android.hardware.security.keymint.Tag;
 import android.os.Build;
 import android.os.StrictMode;
+import android.security.Flags;
 import android.security.KeyPairGeneratorSpec;
 import android.security.KeyStore2;
 import android.security.KeyStoreException;
@@ -853,6 +854,22 @@ public abstract class AndroidKeyStoreKeyPairGeneratorSpi extends KeyPairGenerato
                             KeymasterDefs.KM_TAG_RSA_OAEP_MGF_DIGEST, mgf1Digest
                     ));
                 });
+
+                /* If the MGF1 Digest setter is not set, fall back to the previous behaviour:
+                 * Add, as MGF1 Digest function, all the primary digests.
+                 * Avoid adding the default MGF1 digest as it will have been included in the
+                 * mKeymasterMgf1Digests field.
+                 */
+                if (!getMgf1DigestSetterFlag()) {
+                    final int defaultMgf1Digest = KeyProperties.Digest.toKeymaster(
+                            DEFAULT_MGF1_DIGEST);
+                    ArrayUtils.forEach(mKeymasterDigests, (digest) -> {
+                        if (digest != defaultMgf1Digest) {
+                            params.add(KeyStore2ParameterUtils.makeEnum(
+                                    KeymasterDefs.KM_TAG_RSA_OAEP_MGF_DIGEST, digest));
+                        }
+                    });
+                }
             }
         });
         ArrayUtils.forEach(mKeymasterSignaturePaddings, (padding) -> {
@@ -928,6 +945,16 @@ public abstract class AndroidKeyStoreKeyPairGeneratorSpi extends KeyPairGenerato
         return params;
     }
 
+    private static boolean getMgf1DigestSetterFlag() {
+        try {
+            return Flags.mgf1DigestSetter();
+        } catch (SecurityException e) {
+            Log.w(TAG, "Cannot read MGF1 Digest setter flag value", e);
+            return false;
+        }
+    }
+
+
     private void addAlgorithmSpecificParameters(List<KeyParameter> params) {
         switch (mKeymasterAlgorithm) {
             case KeymasterDefs.KM_ALGORITHM_RSA:
diff --git a/keystore/java/android/security/keystore2/AndroidKeyStoreSpi.java b/keystore/java/android/security/keystore2/AndroidKeyStoreSpi.java
index ddbd93e458fd..2d8c5a380c6b 100644
--- a/keystore/java/android/security/keystore2/AndroidKeyStoreSpi.java
+++ b/keystore/java/android/security/keystore2/AndroidKeyStoreSpi.java
@@ -25,6 +25,7 @@ import android.hardware.security.keymint.HardwareAuthenticatorType;
 import android.hardware.security.keymint.KeyParameter;
 import android.hardware.security.keymint.SecurityLevel;
 import android.os.StrictMode;
+import android.security.Flags;
 import android.security.GateKeeper;
 import android.security.KeyStore2;
 import android.security.KeyStoreParameter;
@@ -256,6 +257,15 @@ public class AndroidKeyStoreSpi extends KeyStoreSpi {
         }
     }
 
+    private static boolean getMgf1DigestSetterFlag() {
+        try {
+            return Flags.mgf1DigestSetter();
+        } catch (SecurityException e) {
+            Log.w(NAME, "Cannot read MGF1 Digest setter flag value", e);
+            return false;
+        }
+    }
+
     @Override
     public Date engineGetCreationDate(String alias) {
         KeyEntryResponse response = getKeyMetadata(alias);
@@ -537,11 +547,31 @@ public class AndroidKeyStoreSpi extends KeyStoreSpi {
                         /* Because of default MGF1 digest is SHA-1. It has to be added in Key
                          * characteristics. Otherwise, crypto operations will fail with Incompatible
                          * MGF1 digest.
+                         * If the MGF1 Digest setter flag isn't set, then the condition in the
+                         * if clause above must be false (cannot have MGF1 digests specified if the
+                         * flag was off). In that case, in addition to adding the default MGF1
+                         * digest, we have to add all the other digests as MGF1 Digests.
+                         *
                          */
                         importArgs.add(KeyStore2ParameterUtils.makeEnum(
                                 KeymasterDefs.KM_TAG_RSA_OAEP_MGF_DIGEST,
                                 KeyProperties.Digest.toKeymaster(DEFAULT_MGF1_DIGEST)
                         ));
+                        if (!getMgf1DigestSetterFlag()) {
+                            final int defaultMgf1Digest = KeyProperties.Digest.toKeymaster(
+                                    DEFAULT_MGF1_DIGEST);
+                            for (String digest : spec.getDigests()) {
+                                int digestToAddAsMgf1Digest = KeyProperties.Digest.toKeymaster(
+                                        digest);
+                                // Do not add the default MGF1 digest as it has been added above.
+                                if (digestToAddAsMgf1Digest != defaultMgf1Digest) {
+                                    importArgs.add(KeyStore2ParameterUtils.makeEnum(
+                                            KeymasterDefs.KM_TAG_RSA_OAEP_MGF_DIGEST,
+                                            digestToAddAsMgf1Digest
+                                    ));
+                                }
+                            }
+                        }
                     }
                 }
             }