Add the commitment type indication and the signing certificate v2 att…

…ributes to NuGet signatures (#234)

jsign-core/src/main/java/net/jsign/AuthenticodeSigner.java

@@ -391,7 +391,7 @@ public void sign(Signable file) throws Exception {
     protected CMSSignedData createSignedData(Signable file) throws Exception {
         // compute the signature
         CMSTypedData contentInfo = file.createSignedContent(digestAlgorithm);
-        CMSSignedDataGenerator generator = createSignedDataGenerator(contentInfo);
+        CMSSignedDataGenerator generator = createSignedDataGenerator(file, contentInfo);
         CMSSignedData sigData = generator.generate(contentInfo, true);
 
         // verify the signature
@@ -419,19 +419,19 @@ protected CMSSignedData createSignedData(Signable file) throws Exception {
         return sigData;
     }
 
-    private CMSSignedDataGenerator createSignedDataGenerator(CMSTypedData contentInfo) throws CMSException, OperatorCreationException, CertificateEncodingException {
+    private CMSSignedDataGenerator createSignedDataGenerator(Signable file, CMSTypedData contentInfo) throws CMSException, OperatorCreationException, CertificateEncodingException {
         List<X509Certificate> fullChain = CertificateUtils.getFullCertificateChain((Collection) Arrays.asList(chain));
         fullChain.removeIf(CertificateUtils::isSelfSigned);
 
         boolean authenticode = AuthenticodeObjectIdentifiers.isAuthenticode(contentInfo.getContentType().getId());
         CMSSignedDataGenerator generator = authenticode ? new AuthenticodeSignedDataGenerator() : new CMSSignedDataGenerator();
         generator.addCertificates(new JcaCertStore(fullChain));
-        generator.addSignerInfoGenerator(createSignerInfoGenerator());
+        generator.addSignerInfoGenerator(createSignerInfoGenerator(file, authenticode));
 
         return generator;
     }
 
-    private SignerInfoGenerator createSignerInfoGenerator() throws OperatorCreationException, CertificateEncodingException {
+    private SignerInfoGenerator createSignerInfoGenerator(Signable file, boolean authenticode) throws OperatorCreationException, CertificateEncodingException {
         // create content signer
         JcaContentSignerBuilder contentSignerBuilder = new JcaContentSignerBuilder(getSignatureAlgorithm());
         if (signatureProvider != null) {
@@ -442,8 +442,14 @@ private SignerInfoGenerator createSignerInfoGenerator() throws OperatorCreationE
         DigestCalculatorProvider digestCalculatorProvider = new JcaDigestCalculatorProviderBuilder().build();
 
         // prepare the authenticated attributes
-        CMSAttributeTableGenerator attributeTableGenerator = new DefaultSignedAttributeTableGenerator(createAuthenticatedAttributes());
-        attributeTableGenerator = new FilteredAttributeTableGenerator(attributeTableGenerator, CMSAttributes.signingTime, CMSAttributes.cmsAlgorithmProtect);
+        List<Attribute> attributes = new ArrayList<>(authenticode ? createAuthenticatedAttributes() : file.createSignedAttributes((X509Certificate) chain[0]));
+        AttributeTable attributeTable = new AttributeTable(new DERSet(attributes.toArray(new ASN1Encodable[0])));
+        CMSAttributeTableGenerator attributeTableGenerator = new DefaultSignedAttributeTableGenerator(attributeTable);
+        if (authenticode) {
+            attributeTableGenerator = new FilteredAttributeTableGenerator(attributeTableGenerator, CMSAttributes.cmsAlgorithmProtect, CMSAttributes.signingTime);
+        } else {
+            attributeTableGenerator = new FilteredAttributeTableGenerator(attributeTableGenerator, CMSAttributes.cmsAlgorithmProtect);
+        }
 
         // fetch the signing certificate
         X509CertificateHolder certificate = new JcaX509CertificateHolder((X509Certificate) chain[0]);
@@ -501,7 +507,7 @@ private void verify(CMSSignedData signedData) throws SignatureException, Operato
      * 
      * @return the authenticated attributes
      */
-    private AttributeTable createAuthenticatedAttributes() {
+    private List<Attribute> createAuthenticatedAttributes() {
         List<Attribute> attributes = new ArrayList<>();
 
         SpcStatementType spcStatementType = new SpcStatementType(AuthenticodeObjectIdentifiers.SPC_INDIVIDUAL_SP_KEY_PURPOSE_OBJID);
@@ -512,7 +518,7 @@ private AttributeTable createAuthenticatedAttributes() {
             attributes.add(new Attribute(AuthenticodeObjectIdentifiers.SPC_SP_OPUS_INFO_OBJID, new DERSet(spcSpOpusInfo)));
         }
 
-        return new AttributeTable(new DERSet(attributes.toArray(new ASN1Encodable[0])));
+        return attributes;
     }
 
     /**

jsign-core/src/main/java/net/jsign/Signable.java

@@ -22,10 +22,14 @@
 import java.nio.charset.Charset;
 import java.security.MessageDigest;
 import java.security.cert.Certificate;
+import java.security.cert.CertificateEncodingException;
+import java.security.cert.X509Certificate;
+import java.util.ArrayList;
 import java.util.List;
 import java.util.ServiceLoader;
 
 import org.bouncycastle.asn1.ASN1Object;
+import org.bouncycastle.asn1.cms.Attribute;
 import org.bouncycastle.asn1.cms.ContentInfo;
 import org.bouncycastle.cms.CMSSignedData;
 import org.bouncycastle.cms.CMSTypedData;
@@ -99,6 +103,16 @@ default byte[] computeDigest(DigestAlgorithm digestAlgorithm) throws IOException
      */
     ASN1Object createIndirectData(DigestAlgorithm digestAlgorithm) throws IOException;
 
+    /**
+     * Creates the signed attributes to include in the signature.
+     *
+     * @param certificate the signing certificate
+     * @since 7.0
+     */
+    default List<Attribute> createSignedAttributes(X509Certificate certificate) throws CertificateEncodingException {
+        return new ArrayList<>();
+    }
+
     /**
      * Checks if the specified certificate is suitable for signing the file.
      *

jsign-core/src/main/java/net/jsign/nuget/NugetFile.java

@@ -22,13 +22,23 @@
 import java.io.InputStream;
 import java.nio.channels.SeekableByteChannel;
 import java.security.MessageDigest;
+import java.security.cert.CertificateEncodingException;
+import java.security.cert.X509Certificate;
+import java.util.ArrayList;
 import java.util.Base64;
 import java.util.Collections;
 import java.util.List;
 
 import org.apache.poi.util.IOUtils;
 import org.bouncycastle.asn1.ASN1Object;
+import org.bouncycastle.asn1.DERSet;
+import org.bouncycastle.asn1.cms.Attribute;
+import org.bouncycastle.asn1.esf.CommitmentTypeIndication;
+import org.bouncycastle.asn1.ess.ESSCertIDv2;
+import org.bouncycastle.asn1.ess.SigningCertificateV2;
 import org.bouncycastle.asn1.pkcs.PKCSObjectIdentifiers;
+import org.bouncycastle.asn1.x500.X500Name;
+import org.bouncycastle.asn1.x509.IssuerSerial;
 import org.bouncycastle.cms.CMSProcessableByteArray;
 import org.bouncycastle.cms.CMSSignedData;
 import org.bouncycastle.cms.CMSTypedData;
@@ -44,6 +54,7 @@
  * A NuGet package.
  * 
  * @see <a href="https://github.com/NuGet/Home/wiki/Package-Signatures-Technical-Details">NuGet Package Signatures Technical Specification</a>
+ * @see <a href="https://github.com/NuGet/Home/wiki/Repository-Signatures-and-Countersignatures-Technical-Specification">NuGet Repository Signatures and Countersignatures Technical Specification</a>
  *
  * @author Sebastian Stamm
  * @since 7.0
@@ -117,6 +128,24 @@ public ASN1Object createIndirectData(DigestAlgorithm digestAlgorithm) {
         throw new UnsupportedOperationException(); // not applicable here
     }
 
+    @Override
+    public List<Attribute> createSignedAttributes(X509Certificate certificate) throws CertificateEncodingException {
+        List<Attribute> attributes = new ArrayList<>();
+
+        CommitmentTypeIndication commitmentTypeIndication = new CommitmentTypeIndication(PKCSObjectIdentifiers.id_cti_ets_proofOfOrigin);
+        attributes.add(new Attribute(PKCSObjectIdentifiers.id_aa_ets_commitmentType, new DERSet(commitmentTypeIndication)));
+        // todo use the id-cti-ets-proofOfReceipt type for repository signatures
+
+        // todo add the nuget-v3-service-index-url and nuget-package-owners attributes for repository signatures
+
+        byte[] certHash = DigestAlgorithm.SHA256.getMessageDigest().digest(certificate.getEncoded());
+        IssuerSerial issuerSerial = new IssuerSerial(X500Name.getInstance(certificate.getIssuerX500Principal().getEncoded()), certificate.getSerialNumber());
+        SigningCertificateV2 signingCertificateV2 = new SigningCertificateV2(new ESSCertIDv2(certHash, issuerSerial));
+        attributes.add(new Attribute(PKCSObjectIdentifiers.id_aa_signingCertificateV2, new DERSet(signingCertificateV2)));
+
+        return attributes;
+    }
+
     @Override
     public List<CMSSignedData> getSignatures() throws IOException {
         if (centralDirectory.entries.containsKey(SIGNATURE_ENTRY)) {

jsign-core/src/test/java/net/jsign/NugetSignerTest.java

@@ -21,6 +21,8 @@
 
 import org.apache.commons.compress.utils.SeekableInMemoryByteChannel;
 import org.apache.commons.io.FileUtils;
+import org.bouncycastle.asn1.cms.CMSAttributes;
+import org.bouncycastle.asn1.pkcs.PKCSObjectIdentifiers;
 import org.junit.Test;
 
 import net.jsign.nuget.NugetFile;
@@ -51,6 +53,11 @@ public void testSign() throws Exception {
             signer.sign(file);
 
             SignatureAssert.assertSigned(file, SHA256);
+
+            // verify the signed attributes
+            SignatureAssert.assertSignedAttribute("commitment type indication", file, PKCSObjectIdentifiers.id_aa_ets_commitmentType);
+            SignatureAssert.assertSignedAttribute("signing certificate v2", file, PKCSObjectIdentifiers.id_aa_signingCertificateV2);
+            SignatureAssert.assertSignedAttribute("signing time", file, CMSAttributes.signingTime);
         }
     }
 

jsign-core/src/test/java/net/jsign/SignatureAssert.java

@@ -19,6 +19,7 @@
 import java.io.IOException;
 import java.util.List;
 
+import org.bouncycastle.asn1.ASN1ObjectIdentifier;
 import org.bouncycastle.asn1.ASN1Sequence;
 import org.bouncycastle.asn1.ASN1TaggedObject;
 import org.bouncycastle.asn1.DEROctetString;
@@ -90,7 +91,9 @@ public static void assertSigned(Signable signable, DigestAlgorithm... algorithms
             assertEquals("Digest algorithm of signature " + i, algorithms[i].oid, si.getDigestAlgorithmID().getAlgorithm());
 
             // Check if the signingTime attribute is present
-            assertNull("signingTime attribute found in signature " + i, signature.getSignerInfos().iterator().next().getSignedAttributes().get(CMSAttributes.signingTime));
+            if (isAuthenticode(signature.getSignedContentTypeOID())) {
+                assertNull("signingTime attribute found in signature " + i, signature.getSignerInfos().iterator().next().getSignedAttributes().get(CMSAttributes.signingTime));
+            }
         }
     }
 
@@ -108,4 +111,14 @@ public static void assertUuidEquals(Signable signable, String expected) throws I
 
         assertEquals("Authenticode UUID", expected.toUpperCase().replaceAll("-", ""), Hex.toHexString(uuid.getOctets()).toUpperCase());
     }
+
+    public static void assertSignedAttribute(String message, Signable signable, ASN1ObjectIdentifier oid) throws IOException {
+        SignerInformation signerInformation = signable.getSignatures().get(0).getSignerInfos().getSigners().iterator().next();
+
+        AttributeTable attributes = signerInformation.getSignedAttributes();
+        assertNotNull(message + " (missing signed attributes)", attributes);
+
+        Attribute attribute = attributes.get(oid);
+        assertNotNull(message + " (missing " + oid + " attribute)", attribute);
+    }
 }