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Commit 09c24c3c authored by Michael Groover's avatar Michael Groover
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Resolve IndexOOBException in SigningDetails#hasAncestor 

When a package that is part of a shareduid is installed / updated its
lineage is compared against the current signature / lineage for the
shareduid. If the new package has more than one signature in the lineage
an IndexOutOfBoundsException is thrown by SigningDetails#hasAncestor
crashing the system server. This commit ensures the ancestor check
is only performed against the current signer for the shareduid.

Fixes: 155134046
Test: atest SigningDetailsTest
Change-Id: Icef9f21c6901e255e5276085259d2f773f41e858
parent f51a85f6

core/java/android/content/pm/PackageParser.java

+1 −1
Original line number Diff line number Diff line
@@ -6016,7 +6016,7 @@ public class PackageParser { 


                // the last entry in pastSigningCertificates is the current signer, ignore it

                for (int i = 0; i < pastSigningCertificates.length - 1; i++) {

                    if (pastSigningCertificates[i].equals(oldDetails.signatures[i])) {

                    if (pastSigningCertificates[i].equals(oldDetails.signatures[0])) {

                        return true;

                    }

                }

core/tests/coretests/src/android/content/pm/SigningDetailsTest.java

0 → 100644
+147 −0
Original line number Diff line number Diff line 
/*

 * Copyright (C) 2020 The Android Open Source Project

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package android.content.pm;



import static android.content.pm.PackageParser.SigningDetails.SignatureSchemeVersion.SIGNING_BLOCK_V3;



import static org.junit.Assert.assertFalse;

import static org.junit.Assert.assertTrue;



import android.content.pm.PackageParser.SigningDetails;

import android.util.ArraySet;



import androidx.test.ext.junit.runners.AndroidJUnit4;

import androidx.test.filters.SmallTest;



import org.junit.Test;

import org.junit.runner.RunWith;



import java.security.PublicKey;



@RunWith(AndroidJUnit4.class)

@SmallTest

public class SigningDetailsTest {

    private static final String FIRST_SIGNATURE = "1234";

    private static final String SECOND_SIGNATURE = "5678";

    private static final String THIRD_SIGNATURE = "9abc";



    @Test

    public void hasAncestor_multipleSignersInLineageWithAncestor_returnsTrue() throws Exception {

        SigningDetails twoSignersInLineageDetails = createSigningDetailsWithLineage(FIRST_SIGNATURE,

                SECOND_SIGNATURE, THIRD_SIGNATURE);

        SigningDetails oneSignerInLineageDetails = createSigningDetailsWithLineage(FIRST_SIGNATURE,

                SECOND_SIGNATURE);



        boolean result = twoSignersInLineageDetails.hasAncestor(oneSignerInLineageDetails);



        assertTrue(result);

    }



    @Test

    public void hasAncestor_oneSignerInLineageAgainstMultipleSignersInLineage_returnsFalse()

            throws Exception {

        SigningDetails twoSignersInLineageDetails = createSigningDetailsWithLineage(FIRST_SIGNATURE,

                SECOND_SIGNATURE, THIRD_SIGNATURE);

        SigningDetails oneSignerInLineageDetails = createSigningDetailsWithLineage(FIRST_SIGNATURE,

                SECOND_SIGNATURE);



        boolean result = oneSignerInLineageDetails.hasAncestor(twoSignersInLineageDetails);



        assertFalse(result);

    }



    @Test

    public void hasAncestor_multipleSignersInLineageAgainstSelf_returnsFalse() throws Exception {

        SigningDetails twoSignersInLineageDetails = createSigningDetailsWithLineage(FIRST_SIGNATURE,

                SECOND_SIGNATURE, THIRD_SIGNATURE);



        boolean result = twoSignersInLineageDetails.hasAncestor(twoSignersInLineageDetails);



        assertFalse(result);

    }



    @Test

    public void hasAncestor_oneSignerInLineageWithAncestor_returnsTrue() throws Exception {

        SigningDetails twoSignersInLineageDetails = createSigningDetailsWithLineage(FIRST_SIGNATURE,

                SECOND_SIGNATURE, THIRD_SIGNATURE);

        SigningDetails oneSignerDetails = createSigningDetails(FIRST_SIGNATURE);



        boolean result = twoSignersInLineageDetails.hasAncestor(oneSignerDetails);



        assertTrue(result);

    }



    @Test

    public void hasAncestor_singleSignerAgainstLineage_returnsFalse() throws Exception {

        SigningDetails oneSignerDetails = createSigningDetails(FIRST_SIGNATURE);

        SigningDetails twoSignersInLineageDetails = createSigningDetailsWithLineage(FIRST_SIGNATURE,

                SECOND_SIGNATURE, THIRD_SIGNATURE);



        boolean result = oneSignerDetails.hasAncestor(twoSignersInLineageDetails);



        assertFalse(result);

    }



    @Test

    public void hasAncestor_multipleSigners_returnsFalse() throws Exception {

        SigningDetails twoSignersDetails = createSigningDetails(FIRST_SIGNATURE, SECOND_SIGNATURE);

        SigningDetails twoSignersInLineageDetails = createSigningDetailsWithLineage(FIRST_SIGNATURE,

                SECOND_SIGNATURE, THIRD_SIGNATURE);



        boolean result1 = twoSignersInLineageDetails.hasAncestor(twoSignersDetails);

        boolean result2 = twoSignersDetails.hasAncestor(twoSignersInLineageDetails);



        assertFalse(result1);

        assertFalse(result2);

    }



    @Test

    public void hasAncestor_unknownDetails_returnsFalse() throws Exception {

        SigningDetails unknownDetails = SigningDetails.UNKNOWN;

        SigningDetails twoSignersInLineageDetails = createSigningDetailsWithLineage(FIRST_SIGNATURE,

                SECOND_SIGNATURE, THIRD_SIGNATURE);



        boolean result1 = twoSignersInLineageDetails.hasAncestor(unknownDetails);

        boolean result2 = unknownDetails.hasAncestor(twoSignersInLineageDetails);



        assertFalse(result1);

        assertFalse(result2);

    }



    private SigningDetails createSigningDetailsWithLineage(String... signers) {

        Signature[] signingHistory = new Signature[signers.length];

        for (int i = 0; i < signers.length; i++) {

            signingHistory[i] = new Signature(signers[i]);

        }

        Signature[] currentSignature = new Signature[]{signingHistory[signers.length - 1]};

        // TODO: Since the PublicKey ArraySet is not used by any of the tests a generic empty Set

        // works for now, but if this is needed in the future consider creating mock PublicKeys that

        // can respond as required for the method under test.

        ArraySet<PublicKey> publicKeys = new ArraySet<>();

        return new SigningDetails(currentSignature, SIGNING_BLOCK_V3, publicKeys, signingHistory);

    }



    private SigningDetails createSigningDetails(String... signers) {

        Signature[] currentSignatures = new Signature[signers.length];

        for (int i = 0; i < signers.length; i++) {

            currentSignatures[i] = new Signature(signers[i]);

        }

        // TODO: Similar to above when tests are added that require this it should be updated to use

        // mocked PublicKeys.

        ArraySet<PublicKey> publicKeys = new ArraySet<>();

        return new SigningDetails(currentSignatures, SIGNING_BLOCK_V3, publicKeys, null);

    }

}