Fix producer line when LTA signatures are used

DEVSIX-9024

Author: Alexandr Pliushchou

commons/src/main/java/com/itextpdf/commons/actions/producer/ProducerBuilder.java

@@ -109,16 +109,31 @@ public static String modifyProducer(List<? extends AbstractProductProcessITextEv
         }
 
         final String newProducer = buildProducer(confirmedEvents);
-        if (oldProducer == null || oldProducer.isEmpty()) {
-            return newProducer;
+        //if the last time document was modified or created with the itext of the same version,
+        //then no changes occur.
+        return mergeProducerLines(oldProducer, newProducer);
+    }
+
+    /**
+     * Merges two producer lines. If first producer line <code>null</code> or empty, it will be replaced with the second one.
+     * Otherwise second producer line will be attached with <code>modified using</code> prefix. If first producer line
+     * already contains <code>modified using</code> substring with the second producer line at the end, first producer
+     * line will be returned unchanged.
+     *
+     * @param firstProducer first producer line
+     * @param secondProducer second producer line
+
+     * @return modified producer line
+     */
+    public static String mergeProducerLines(String firstProducer, String secondProducer) {
+        if (firstProducer == null || firstProducer.isEmpty()) {
+            return secondProducer;
         } else {
-            //if the last time document was modified or created with the itext of the same version,
-            //then no changes occur.
-            if (oldProducer.equals(newProducer)
-                    || oldProducer.endsWith(MODIFIED_USING + newProducer)) {
-                return oldProducer;
+            if (firstProducer.equals(secondProducer)
+                    || firstProducer.endsWith(MODIFIED_USING + secondProducer)) {
+                return firstProducer;
             } else {
-                return oldProducer + MODIFIED_USING + newProducer;
+                return firstProducer + MODIFIED_USING + secondProducer;
             }
         }
     }

commons/src/test/java/com/itextpdf/commons/actions/producer/ProducerBuilderTest.java

@@ -220,6 +220,29 @@ public void oldProducerEqualsCurrentProducerTest() {
         Assertions.assertEquals("some Author", newProducerLine);
     }
 
+    @Test
+    public void mergeEquivalentProducersTest() {
+        String producerLine = "some producer";
+        String result = ProducerBuilder.mergeProducerLines(producerLine, producerLine);
+        Assertions.assertEquals(producerLine, result);
+    }
+
+    @Test
+    public void mergeDifferentProducersTest() {
+        String producerLine = "some producer";
+        String secondProducerLine = "another producer";
+        String result = ProducerBuilder.mergeProducerLines(producerLine, secondProducerLine);
+        Assertions.assertEquals(producerLine + "; modified using " + secondProducerLine, result);
+    }
+
+    @Test
+    public void mergeProducerEndsWithSecondProducerTest() {
+        String producerLine = "some producer; modified using another producer";
+        String secondProducerLine = "another producer";
+        String result = ProducerBuilder.mergeProducerLines(producerLine, secondProducerLine);
+        Assertions.assertEquals(producerLine, result);
+    }
+
     private List<ConfirmedEventWrapper> getEvents(String initialProducerLine, int ... indexes) {
         List<ConfirmedEventWrapper> events = new ArrayList<>();
 

kernel/src/main/java/com/itextpdf/kernel/actions/events/FlushPdfDocumentEvent.java

@@ -74,33 +74,35 @@ protected void doAction() {
         }
         List<AbstractProductProcessITextEvent> events = getEvents(pdfDocument.getDocumentIdWrapper());
 
+        final String oldProducer = pdfDocument.getDocumentInfo().getProducer();
+        String newProducer;
         if (events == null || events.isEmpty()) {
             final ProductData productData = ITextCoreProductData.getInstance();
-            final String noEventProducer = "iText\u00ae \u00a9" + productData.getSinceCopyrightYear() + "-"
-                    + productData.getToCopyrightYear() + " Apryse Group NV (no registered products)";
-            pdfDocument.getDocumentInfo().setProducer(noEventProducer);
-            return;
-        }
-
-        final Set<String> products = new HashSet<>();
-        for (final AbstractProductProcessITextEvent event : events) {
-            pdfDocument.getFingerPrint().registerProduct(event.getProductData());
-            if (event.getConfirmationType() == EventConfirmationType.ON_CLOSE) {
-                EventManager.getInstance().onEvent(new ConfirmEvent(pdfDocument.getDocumentIdWrapper(), event));
+            final String noEventProducer = "iText\u00ae " + productData.getPublicProductName() + " " +
+                    productData.getVersion() + " \u00a9" + productData.getSinceCopyrightYear() + "-"
+                    + productData.getToCopyrightYear() + " Apryse Group NV";
+            newProducer = ProducerBuilder.mergeProducerLines(oldProducer, noEventProducer);
+        } else {
+            final Set<String> products = new HashSet<>();
+            for (final AbstractProductProcessITextEvent event : events) {
+                pdfDocument.getFingerPrint().registerProduct(event.getProductData());
+                if (event.getConfirmationType() == EventConfirmationType.ON_CLOSE) {
+                    EventManager.getInstance().onEvent(new ConfirmEvent(pdfDocument.getDocumentIdWrapper(), event));
+                }
+                products.add(event.getProductName());
             }
-            products.add(event.getProductName());
-        }
 
-        for (final String product : products) {
-            final ITextProductEventProcessor processor = getActiveProcessor(product);
-            if (processor == null && LOGGER.isWarnEnabled()) {
-                LOGGER.warn(MessageFormatUtil.format(KernelLogMessageConstant.UNKNOWN_PRODUCT_INVOLVED, product));
+            for (final String product : products) {
+                final ITextProductEventProcessor processor = getActiveProcessor(product);
+                if (processor == null && LOGGER.isWarnEnabled()) {
+                    LOGGER.warn(MessageFormatUtil.format(KernelLogMessageConstant.UNKNOWN_PRODUCT_INVOLVED, product));
+                }
             }
+
+            newProducer = ProducerBuilder.modifyProducer(getConfirmedEvents(pdfDocument.getDocumentIdWrapper()),
+                    oldProducer);
         }
 
-        final String oldProducer = pdfDocument.getDocumentInfo().getProducer();
-        final String newProducer =
-                ProducerBuilder.modifyProducer(getConfirmedEvents(pdfDocument.getDocumentIdWrapper()), oldProducer);
         pdfDocument.getDocumentInfo().setProducer(newProducer);
     }
 

kernel/src/test/java/com/itextpdf/kernel/actions/events/FlushPdfDocumentEventTest.java

@@ -142,10 +142,14 @@ public void doActionNullDocumentTest() {
 
     @Test
     public void doActionNullEventMapTest() throws IOException {
+        final ProductData productData = ITextCoreProductData.getInstance();
+        final String expectedProducer = "iText\u00ae " + productData.getPublicProductName() + " " +
+                productData.getVersion() + " \u00a9" + productData.getSinceCopyrightYear() + "-"
+                + productData.getToCopyrightYear() + " Apryse Group NV";
         try (PdfDocument document = new DummyPdfDocument(new PdfReader(SOURCE_FOLDER + "hello.pdf"))) {
             AssertUtil.doesNotThrow(() -> new FlushPdfDocumentEvent(document).doAction());
             Assertions.assertTrue(document.getDocumentInfo().getProducer()
-                    .contains("Apryse Group NV (no registered products)"));
+                    .contains(expectedProducer));
         }
     }
 

sign/src/test/java/com/itextpdf/signatures/sign/PdfPadesSignerTest.java

@@ -23,16 +23,21 @@ This file is part of the iText (R) project.
 package com.itextpdf.signatures.sign;
 
 import com.itextpdf.bouncycastleconnector.BouncyCastleFactoryCreator;
+import com.itextpdf.commons.actions.data.ProductData;
 import com.itextpdf.commons.bouncycastle.IBouncyCastleFactory;
 import com.itextpdf.commons.bouncycastle.operator.AbstractOperatorCreationException;
 import com.itextpdf.commons.bouncycastle.pkcs.AbstractPKCSException;
 import com.itextpdf.commons.utils.FileUtil;
 import com.itextpdf.commons.utils.MessageFormatUtil;
 import com.itextpdf.forms.form.element.SignatureFieldAppearance;
+import com.itextpdf.io.source.ByteArrayOutputStream;
+import com.itextpdf.kernel.actions.data.ITextCoreProductData;
 import com.itextpdf.kernel.crypto.DigestAlgorithms;
 import com.itextpdf.kernel.exceptions.PdfException;
 import com.itextpdf.kernel.geom.Rectangle;
+import com.itextpdf.kernel.pdf.PdfDocument;
 import com.itextpdf.kernel.pdf.PdfReader;
+import com.itextpdf.kernel.pdf.PdfWriter;
 import com.itextpdf.signatures.ICrlClient;
 import com.itextpdf.signatures.IExternalSignature;
 import com.itextpdf.signatures.PdfPadesSigner;
@@ -48,6 +53,7 @@ This file is part of the iText (R) project.
 import com.itextpdf.test.ExtendedITextTest;
 import com.itextpdf.test.TestUtil;
 
+import java.io.ByteArrayInputStream;
 import java.io.IOException;
 import java.security.GeneralSecurityException;
 import java.security.PrivateKey;
@@ -56,6 +62,7 @@ This file is part of the iText (R) project.
 import java.security.cert.CertificateException;
 import java.security.cert.X509Certificate;
 import java.util.Arrays;
+
 import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.Assumptions;
 import org.junit.jupiter.api.BeforeAll;
@@ -298,6 +305,58 @@ private SignerProperties createSignerProperties() {
         return signerProperties;
     }
 
+    @Test
+    public void producerLineWithMetaInfoUsedTest()
+            throws IOException, GeneralSecurityException, AbstractOperatorCreationException, AbstractPKCSException {
+        String fileName = "producerLineWithMetaInfoUsed.pdf";
+        String outFileName = destinationFolder + fileName;
+        String srcFileName = sourceFolder + "helloWorldDoc.pdf";
+        String signCertFileName = certsSrc + "signCertRsa01.pem";
+        String tsaCertFileName = certsSrc + "tsCertRsa.pem";
+        String caCertFileName = certsSrc + "rootRsa.pem";
+
+        Certificate[] signRsaChain = PemFileHelper.readFirstChain(signCertFileName);
+        PrivateKey signRsaPrivateKey = PemFileHelper.readFirstKey(signCertFileName, password);
+        IExternalSignature pks =
+                new PrivateKeySignature(signRsaPrivateKey, DigestAlgorithms.SHA256, FACTORY.getProviderName());
+        Certificate[] tsaChain = PemFileHelper.readFirstChain(tsaCertFileName);
+        PrivateKey tsaPrivateKey = PemFileHelper.readFirstKey(tsaCertFileName, password);
+        X509Certificate caCert = (X509Certificate) PemFileHelper.readFirstChain(caCertFileName)[0];
+        PrivateKey caPrivateKey = PemFileHelper.readFirstKey(caCertFileName, password);
+
+        SignerProperties signerProperties = new SignerProperties();
+
+        PdfPadesSigner padesSigner = createPdfPadesSigner(srcFileName, outFileName);
+
+        TestTsaClient testTsa = new TestTsaClient(Arrays.asList(tsaChain), tsaPrivateKey);
+        ICrlClient crlClient = new TestCrlClient().addBuilderForCertIssuer(caCert, caPrivateKey);
+        TestOcspClient ocspClient = new TestOcspClient().addBuilderForCertIssuer(caCert, caPrivateKey);
+
+        padesSigner.setOcspClient(ocspClient).setCrlClient(crlClient);
+
+        padesSigner.signWithBaselineLTAProfile(signerProperties, signRsaChain, pks, testTsa);
+
+        byte[] docBytes;
+        try (ByteArrayOutputStream outputStream = new ByteArrayOutputStream()) {
+            new PdfDocument(new PdfReader(srcFileName) ,new PdfWriter(outputStream)).close();
+            docBytes = outputStream.toByteArray();
+        }
+
+        try (PdfDocument signedPdf = new PdfDocument(new PdfReader(outFileName))) {
+            try (PdfDocument regularPdf = new PdfDocument(new PdfReader(new ByteArrayInputStream(docBytes)))) {
+                ProductData productData = ITextCoreProductData.getInstance();
+                String newlyAddedProducer = "iText\u00ae " + productData.getPublicProductName() + " " +
+                        productData.getVersion() + " \u00a9" + productData.getSinceCopyrightYear() + "-"
+                        + productData.getToCopyrightYear() + " Apryse Group NV";
+                String actualProducerLine = signedPdf.getDocumentInfo().getProducer();
+                String regularProducerLine = regularPdf.getDocumentInfo().getProducer();
+
+                Assertions.assertTrue(actualProducerLine.contains(regularProducerLine));
+                Assertions.assertTrue(actualProducerLine.contains(newlyAddedProducer));
+            }
+        }
+    }
+
     private PdfPadesSigner createPdfPadesSigner(String srcFileName, String outFileName) throws IOException {
         return new PdfPadesSigner(new PdfReader(FileUtil.getInputStreamForFile(srcFileName)),
                 FileUtil.getFileOutputStream(outFileName));