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Fix double-wrapping of IssuerSignedItem.
The root problem is that both encodeStaticAuthData() and decodeStaticAuthData() have a bug where IssuerSignedItem is wrapped in a #6.24-tagged bstr twice. For self-signed credentials provisioned on the device via Utility.provisionSelfSignedCredential() this turned out to not be a problem because the two bugs cancel each other out. However for applications where the StaticAuthData (e.g. MSO and the digest id mapping) is generated outside the device - the usual case for production-level mDLs - this ends up being a problem because the generated StaticAuthData CBOR fails to decode because of the bug in decodeStaticAuthData(). Fix this by slightly reworking the API so IssuerSignedItem blobs are passed around, not IssuedSignedItemBytes. Specifically this affects the following public APIs: - Utility.mergeIssuerSigned() - Utility.decodeStaticAuthData() - Utility.encodeStaticAuthData() - DeviceResponseGenerator.addDocument() This change won't affect the common path where the mdoc application is just using DeviceResponseGenerator.addDocument() together with Utility.decodeStaticAuthData(). Additionally, since this is a bug in how StaticAuthData is encoded and this is stored on disk, you'll need to uninstall the reference app and install it again to force creation of a new self-signed credential. Test: New unit tests and all unit tests pass. Test: Manually tested with reference apps.
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identity/src/androidTest/java/com/android/identity/StaticAuthDataTest.java
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| /* | ||
| * Copyright 2022 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. | ||
| */ | ||
|
|
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| package com.android.identity; | ||
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| import android.util.Pair; | ||
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| import androidx.test.ext.junit.runners.AndroidJUnit4; | ||
| import androidx.test.filters.SmallTest; | ||
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| import org.junit.Assert; | ||
| import org.junit.Test; | ||
| import org.junit.runner.RunWith; | ||
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| import java.util.Arrays; | ||
| import java.util.HashMap; | ||
| import java.util.List; | ||
| import java.util.Map; | ||
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| import co.nstant.in.cbor.CborBuilder; | ||
| import co.nstant.in.cbor.builder.MapBuilder; | ||
| import co.nstant.in.cbor.model.DataItem; | ||
| import co.nstant.in.cbor.model.SimpleValue; | ||
| import co.nstant.in.cbor.model.UnicodeString; | ||
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| @SuppressWarnings("deprecation") | ||
| @RunWith(AndroidJUnit4.class) | ||
| public class StaticAuthDataTest { | ||
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| @Test | ||
| @SmallTest | ||
| public void testDecodeStaticAuthData() throws Exception { | ||
| /* Manually builds up CBOR that conforms to EXAMPLE_STATIC_AUTH_DATA_HEX | ||
| * defined in the bottom of this class. Then checks that decodeStaticAuthData() | ||
| * decodes it correctly. | ||
| */ | ||
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| CborBuilder builder = new CborBuilder(); | ||
| MapBuilder<CborBuilder> outerBuilder = builder.addMap(); | ||
| outerBuilder.addKey("org.namespace"); | ||
| outerBuilder.end(); | ||
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| DataItem issuerSignedItem = new CborBuilder() | ||
| .addMap() | ||
| .put("digestID", 42) | ||
| .put("random", new byte[] {0x50, 0x51, 0x52}) | ||
| .put("elementIdentifier", "dataElementName") | ||
| .put(new UnicodeString("elementValue"), SimpleValue.NULL) | ||
| .end() | ||
| .build().get(0); | ||
| byte[] encodedIssuerSignedItem = Util.cborEncode(issuerSignedItem); | ||
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| DataItem issuerSignedItem2 = new CborBuilder() | ||
| .addMap() | ||
| .put("digestID", 43) | ||
| .put("random", new byte[] {0x53, 0x54, 0x55}) | ||
| .put("elementIdentifier", "dataElementName2") | ||
| .put(new UnicodeString("elementValue"), SimpleValue.NULL) | ||
| .end() | ||
| .build().get(0); | ||
| byte[] encodedIssuerSignedItem2 = Util.cborEncodeWithoutCanonicalizing(issuerSignedItem2); | ||
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| DataItem digestIdMappingItem = new CborBuilder() | ||
| .addMap() | ||
| .putArray("org.namespace") | ||
| .add(Util.cborBuildTaggedByteString(encodedIssuerSignedItem)) | ||
| .add(Util.cborBuildTaggedByteString(encodedIssuerSignedItem2)) | ||
| .end() | ||
| .end() | ||
| .build().get(0); | ||
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| byte[] staticAuthData = Util.cborEncode(new CborBuilder() | ||
| .addMap() | ||
| .put(new UnicodeString("digestIdMapping"), digestIdMappingItem) | ||
| // Make issuerAuth look like a valid COSE_Sign1 | ||
| .putArray("issuerAuth") // IssuerAuth | ||
| .addArray().end() | ||
| .add(SimpleValue.NULL) | ||
| .add(new byte[] {0x01, 0x02}) | ||
| .end() | ||
| .end() | ||
| .build().get(0)); | ||
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| Assert.assertEquals(EXAMPLE_STATIC_AUTH_DATA_HEX, Util.toHex(staticAuthData)); | ||
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| // Now check that decodeStaticAuthData() correctly decodes CBOR conforming to this CDDL | ||
| Pair<Map<String, List<byte[]>>, byte[]> val = Utility.decodeStaticAuthData(staticAuthData); | ||
| Map<String, List<byte[]>> digestIdMapping = val.first; | ||
| byte[] encodedStaticAuthData = val.second; | ||
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| // Check that the IssuerSignedItem instances are correctly decoded and the order | ||
| // of the map matches what was put in above | ||
| Assert.assertEquals(1, digestIdMapping.size()); | ||
| List<byte[]> list = digestIdMapping.get("org.namespace"); | ||
| Assert.assertNotNull(list); | ||
| Assert.assertEquals(2, list.size()); | ||
| Assert.assertEquals("{\n" + | ||
| " 'random' : [0x50, 0x51, 0x52],\n" + | ||
| " 'digestID' : 42,\n" + | ||
| " 'elementValue' : null,\n" + | ||
| " 'elementIdentifier' : 'dataElementName'\n" + | ||
| "}", Util.cborPrettyPrint(list.get(0))); | ||
| Assert.assertEquals("{\n" + | ||
| " 'digestID' : 43,\n" + | ||
| " 'random' : [0x53, 0x54, 0x55],\n" + | ||
| " 'elementIdentifier' : 'dataElementName2',\n" + | ||
| " 'elementValue' : null\n" + | ||
| "}", Util.cborPrettyPrint(list.get(1))); | ||
| } | ||
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| @Test | ||
| @SmallTest | ||
| public void testEncodeStaticAuthData() throws Exception { | ||
| /* Uses encodeStaticAuthData() to build up CBOR that conforms to | ||
| * EXAMPLE_STATIC_AUTH_DATA_HEX defined in the bottom of this class. | ||
| * Then checks that the same bytes are produced. | ||
| */ | ||
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| DataItem issuerSignedItem = new CborBuilder() | ||
| .addMap() | ||
| .put("digestID", 42) | ||
| .put("random", new byte[] {0x50, 0x51, 0x52}) | ||
| .put("elementIdentifier", "dataElementName") | ||
| .put(new UnicodeString("elementValue"), SimpleValue.NULL) | ||
| .end() | ||
| .build().get(0); | ||
| byte[] encodedIssuerSignedItem = Util.cborEncode(issuerSignedItem); | ||
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| DataItem issuerSignedItem2 = new CborBuilder() | ||
| .addMap() | ||
| .put("digestID", 43) | ||
| .put("random", new byte[] {0x53, 0x54, 0x55}) | ||
| .put("elementIdentifier", "dataElementName2") | ||
| .put(new UnicodeString("elementValue"), SimpleValue.NULL) | ||
| .end() | ||
| .build().get(0); | ||
| byte[] encodedIssuerSignedItem2 = Util.cborEncodeWithoutCanonicalizing(issuerSignedItem2); | ||
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| Map<String, List<byte[]>> issuerSignedMapping = new HashMap<>(); | ||
| issuerSignedMapping.put("org.namespace", | ||
| Arrays.asList(encodedIssuerSignedItem, encodedIssuerSignedItem2)); | ||
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| byte[] encodedIssuerAuth = Util.cborEncode(new CborBuilder() | ||
| .addArray() | ||
| .addArray() | ||
| .end() | ||
| .add(SimpleValue.NULL) | ||
| .add(new byte[] {0x01, 0x02}) | ||
| .end() | ||
| .build().get(0)); | ||
|
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| byte[] staticAuthData = Utility.encodeStaticAuthData(issuerSignedMapping, encodedIssuerAuth); | ||
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| Assert.assertEquals(EXAMPLE_STATIC_AUTH_DATA_HEX, Util.toHex(staticAuthData)); | ||
| } | ||
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| // If you go to cbor.me with the hex value below you'll get | ||
| // | ||
| // { | ||
| // "issuerAuth": [[], null, << 1, 2 >>], | ||
| // "digestIdMapping": { | ||
| // "org.namespace": [ | ||
| // 24(<< { | ||
| // "random": h'505152', | ||
| // "digestID": 42, | ||
| // "elementValue": null, | ||
| // "elementIdentifier": "dataElementName" | ||
| // } >>), | ||
| // 24(<< { | ||
| // "digestID": 43, | ||
| // "random": h'535455', | ||
| // "elementIdentifier": "dataElementName2", | ||
| // "elementValue": null | ||
| // } >>) | ||
| // ] | ||
| // } | ||
| // } | ||
| // | ||
| // which by inspection matches this CDDL: | ||
| // | ||
| // StaticAuthData = { | ||
| // "digestIdMapping": DigestIdMapping, | ||
| // "issuerAuth" : IssuerAuth | ||
| // } | ||
| // | ||
| // DigestIdMapping = { | ||
| // NameSpace => [ + IssuerSignedItemBytes ] | ||
| // } | ||
| // | ||
| // ; Defined in ISO 18013-5 | ||
| // ; | ||
| // NameSpace = String | ||
| // DataElementIdentifier = String | ||
| // DigestID = uint | ||
| // IssuerAuth = COSE_Sign1 ; The payload is MobileSecurityObjectBytes | ||
| // | ||
| // IssuerSignedItemBytes = #6.24(bstr .cbor IssuerSignedItem) | ||
| // | ||
| // IssuerSignedItem = { | ||
| // "digestID" : uint, ; Digest ID for issuer data auth | ||
| // "random" : bstr, ; Random value for issuer data auth | ||
| // "elementIdentifier" : DataElementIdentifier, ; Data element identifier | ||
| // "elementValue" : NULL ; Placeholder for Data element value | ||
| // } | ||
| // | ||
| // TODO: We should add support for 'emb cbor' in Util.cborPrettyPrint() so we can just | ||
| // compare against a printed value instead of a hexdump. | ||
| // | ||
| private final String EXAMPLE_STATIC_AUTH_DATA_HEX = | ||
| "a26a697373756572417574688380f64201026f64696765737449644d61707069" | ||
| + "6e67a16d6f72672e6e616d65737061636582d8185847a46672616e646f6d4350" | ||
| + "5152686469676573744944182a6c656c656d656e7456616c7565f671656c656d" | ||
| + "656e744964656e7469666965726f64617461456c656d656e744e616d65d81858" | ||
| + "48a4686469676573744944182b6672616e646f6d4353545571656c656d656e74" | ||
| + "4964656e7469666965727064617461456c656d656e744e616d65326c656c656d" | ||
| + "656e7456616c7565f6"; | ||
| } |
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