feat: restrict obfuscation to font core media types

EPUB 3.3 explicitly restricts the font obfuscation algorithm to resources being declared as dont Core Media Types. This commit: - registers obfuscated resources to the OCFPackage when parsing the `encyrption.xml` file (with parsing location) - checks that if obfuscated resources are declared in Package Documents, they have a font core media type - add and tweak tests Fix #1291
w3c · Jan 24, 2022 · a229edf · a229edf
1 parent 73fe57c
commit a229edf
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Showing 29 changed files with 141 additions and 23 deletions.
diff --git a/src/main/java/com/adobe/epubcheck/messages/DefaultSeverities.java b/src/main/java/com/adobe/epubcheck/messages/DefaultSeverities.java
@@ -302,6 +302,7 @@ private void initialize()
     severities.put(MessageId.PKG_023, Severity.USAGE);
     severities.put(MessageId.PKG_024, Severity.INFO);
     severities.put(MessageId.PKG_025, Severity.ERROR);
+    severities.put(MessageId.PKG_026, Severity.ERROR);
 
     // Resources
     severities.put(MessageId.RSC_001, Severity.ERROR);

diff --git a/src/main/java/com/adobe/epubcheck/messages/MessageId.java b/src/main/java/com/adobe/epubcheck/messages/MessageId.java
@@ -296,6 +296,7 @@ public enum MessageId implements Comparable<MessageId>
   PKG_023("PKG-023"),
   PKG_024("PKG-024"),
   PKG_025("PKG-025"),
+  PKG_026("PKG-026"),
 
   // Messages relating to resources
   RSC_001("RSC-001"),

diff --git a/src/main/java/com/adobe/epubcheck/ocf/EncryptionHandler.java b/src/main/java/com/adobe/epubcheck/ocf/EncryptionHandler.java
@@ -22,14 +22,15 @@
 
 package com.adobe.epubcheck.ocf;
 
+import java.io.UnsupportedEncodingException;
+import java.net.URLDecoder;
+
+import com.adobe.epubcheck.api.EPUBLocation;
 import com.adobe.epubcheck.util.HandlerUtil;
 import com.adobe.epubcheck.xml.XMLElement;
 import com.adobe.epubcheck.xml.XMLHandler;
 import com.adobe.epubcheck.xml.XMLParser;
 
-import java.io.UnsupportedEncodingException;
-import java.net.URLDecoder;
-
 public class EncryptionHandler implements XMLHandler
 {
   private final OCFPackage ocf;
@@ -83,6 +84,7 @@ public void startElement()
       if (algorithm.equals("http://www.idpf.org/2008/embedding"))
       {
         ocf.setEncryption(entryName, new IDPFFontManglingFilter(null));
+        ocf.setObfuscated(entryName, parser.getLocation());
       }
       else if (algorithm.equals("http://ns.adobe.com/pdf/enc#RC"))
       {

diff --git a/src/main/java/com/adobe/epubcheck/ocf/OCFChecker.java b/src/main/java/com/adobe/epubcheck/ocf/OCFChecker.java
@@ -51,9 +51,11 @@
 import com.adobe.epubcheck.api.Report;
 import com.adobe.epubcheck.messages.MessageId;
 import com.adobe.epubcheck.opf.OPFChecker;
+import com.adobe.epubcheck.opf.OPFChecker30;
 import com.adobe.epubcheck.opf.OPFData;
 import com.adobe.epubcheck.opf.OPFHandler;
 import com.adobe.epubcheck.opf.OPFHandler30;
+import com.adobe.epubcheck.opf.OPFItem;
 import com.adobe.epubcheck.opf.ValidationContext;
 import com.adobe.epubcheck.opf.ValidationContext.ValidationContextBuilder;
 import com.adobe.epubcheck.util.CheckUtil;
@@ -64,6 +66,7 @@
 import com.adobe.epubcheck.xml.XMLParser;
 import com.adobe.epubcheck.xml.XMLValidator;
 import com.adobe.epubcheck.xml.XMLValidators;
+import com.google.common.base.Optional;
 import com.google.common.base.Preconditions;
 import com.google.common.base.Predicate;
 import com.google.common.base.Predicates;
@@ -349,7 +352,7 @@ else if (!normalizedEntriesSet.add(Normalizer.normalize(entry, Form.NFC)))
       for (final String entry : ocf.getFileEntries())
       {
         ocf.reportMetadata(entry, report);
-
+        
         // if the entry is not in the whitelist (META-INF/* + mimetype)
         // and not declared in (one of) the OPF document(s)
         if (!entry.startsWith("META-INF/") && !entry.startsWith("META-INF\\")
@@ -371,6 +374,27 @@ public boolean apply(OPFHandler opfHandler)
           report.message(MessageId.OPF_003, EPUBLocation.create(ocf.getName()), entry);
         }
         OCFFilenameChecker.checkCompatiblyEscaped(entry, report, validationVersion);
+
+        // check obfuscated resource are Font Core Media Types
+        if (ocf.isObfuscatedFont(entry))
+        {
+          for (OPFHandler opf : opfHandlers)
+          {
+            // try to find the first Package Document where the entry is
+            // declared
+            Optional<OPFItem> item = opf.getItemByPath(entry);
+            if (item.isPresent())
+            {
+              // report if it is not a font core media type
+              if (!OPFChecker30.isBlessedFontType(item.get().getMimeType()))
+              {
+                report.message(MessageId.PKG_026, ocf.getObfuscationDeclarationLocation(entry),
+                    item.get().getMimeType(), opf.getPath());
+              }
+              break;
+            }
+          }
+        }
       }
 
       // check all directory entries without duplicates

diff --git a/src/main/java/com/adobe/epubcheck/ocf/OCFPackage.java b/src/main/java/com/adobe/epubcheck/ocf/OCFPackage.java
@@ -4,7 +4,6 @@
 import java.io.InputStream;
 import java.util.Collections;
 import java.util.HashMap;
-import java.util.Hashtable;
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
@@ -26,7 +25,8 @@
 
 public abstract class OCFPackage implements GenericResourceProvider
 {
-  final Hashtable<String, EncryptionFilter> enc;
+  final Map<String, EncryptionFilter> enc = new HashMap<>();
+  final Map<String, EPUBLocation> obfuscated = new HashMap<>();
   String uniqueIdentifier;
   private Report reporter;
   private final Supplier<OCFData> ocfData = Suppliers.memoize(new Supplier<OCFData>()
@@ -72,16 +72,17 @@ public Map<String, OPFData> get()
         }
       });
 
-  public OCFPackage()
-  {
-    this.enc = new Hashtable<String, EncryptionFilter>();
-  }
 
   public void setEncryption(String name, EncryptionFilter encryptionFilter)
   {
     enc.put(name, encryptionFilter);
   }
 
+  public void setObfuscated(String name, EPUBLocation location)
+  {
+    obfuscated.put(name, location);
+  }
+
   /**
    * @param name
    *          the name of a relative file that is possibly in the container
@@ -133,6 +134,27 @@ public boolean canDecrypt(String fileName)
     return filter == null || filter.canDecrypt();
   }
 
+  /**
+   * @param path path of the resource to test
+   * @return true if that resource is encrypted with the font obfuscation algorithm
+   */
+  public boolean isObfuscatedFont(String path)
+  {
+    return obfuscated.containsKey(path);
+  }
+
+  /**
+   * Returns the location in META-INF/encryption.xml where the given resource
+   * is declared as an obfuscated font, or <code>null</code> if it is not.
+   * 
+   * @param path path of the resource to test
+   * @return the location in META-INF/encryption.xml, or null
+   */
+  public EPUBLocation getObfuscationDeclarationLocation(String path)
+  {
+    return obfuscated.get(path);
+  }
+
   /**
    * This method parses the container entry and stores important data, but does
    * /not/ validate the container against a schema definition.

diff --git a/src/main/java/com/adobe/epubcheck/opf/OPFHandler.java b/src/main/java/com/adobe/epubcheck/opf/OPFHandler.java
@@ -127,6 +127,10 @@ public OPFHandler(ValidationContext context, XMLParser parser)
     this.report = context.report;
     this.parser = parser;
   }
+
+  public String getPath() {
+    return path;
+  }
 
   public boolean getOpf12PackageFile()
   {

diff --git a/src/main/resources/com/adobe/epubcheck/messages/MessageBundle.properties b/src/main/resources/com/adobe/epubcheck/messages/MessageBundle.properties
@@ -313,7 +313,8 @@ PKG_022=Wrong file extension for image. The image is a "%1$s" file but has the f
 PKG_023=Validating the EPUB against version 2.0, default validation profile will be used.
 PKG_024=Uncommon EPUB file extension.
 PKG_024_SUG=For maximum compatibility, use ".epub".
-PKG_025=Publication resource must not be located in the META-INF directory 
+PKG_025=Publication resource must not be located in the META-INF directory
+PKG_026=Obfuscated resource must be a Font Core Media Type (was declared as "%1$s" in "%2$s").  
 
 #Resources
 RSC_001=File "%1$s" could not be found.

diff --git a/src/test/resources/epub3/container-publication.feature b/src/test/resources/epub3/container-publication.feature
@@ -119,9 +119,10 @@ Feature: EPUB 3 ▸ Open Container Format ▸ Full Publication Checks
     And the message contains 'expected element "encryption"'
     And no other errors or warnings are reported
 
-  Scenario: Report an unknown encryption scheme
+  Scenario: Verify encryption can be used
+    (but file will not be parsed)
     Given the reporting level is set to INFO
-    When checking EPUB 'ocf-encryption-unknown-error'
+    When checking EPUB 'ocf-encryption-unknown-valid'
     Then info RSC-004 is reported
     And no other errors or warnings are reported
 
@@ -180,16 +181,21 @@ Feature: EPUB 3 ▸ Open Container Format ▸ Full Publication Checks
 
 
   ## 5. Resource Obfuscation
-  
-  Scenario: Verify a publication with obfuscated resource (here a font file)
+
+  Scenario: Verify a publication with obfuscated font
     When checking EPUB 'ocf-obfuscation-valid'
     Then no errors or warnings are reported
 
-  Scenario: Verify a publication with obfuscation of a usually-parsed resource (here an SVG image)
-    When checking EPUB 'ocf-obfuscation-svg-valid'
-    Then info RSC-004 is reported
+  Scenario: Report an obfuscated font that is not a Core Media Type
+    When checking EPUB 'ocf-obfuscation-not-cmt-error'
+    Then error PKG-026 is reported
     And no errors or warnings are reported
-
+
+  Scenario: Report an obfuscated font that is not a font
+    When checking EPUB 'ocf-obfuscation-not-font-error'
+    Then error PKG-026 is reported
+    And no errors or warnings are reported
+
 
   ## C. the 'application/epub+zip' Media Type
 

diff --git a/...tion-unknown-error/EPUB/content_001.xhtml → ...tion-unknown-valid/EPUB/content_001.xhtml b/...tion-unknown-error/EPUB/content_001.xhtml → ...tion-unknown-valid/EPUB/content_001.xhtml
diff --git a/...f-encryption-unknown-error/EPUB/nav.xhtml → ...f-encryption-unknown-valid/EPUB/nav.xhtml b/...f-encryption-unknown-error/EPUB/nav.xhtml → ...f-encryption-unknown-valid/EPUB/nav.xhtml
diff --git a/...encryption-unknown-error/EPUB/package.opf → ...encryption-unknown-valid/EPUB/package.opf b/...encryption-unknown-error/EPUB/package.opf → ...encryption-unknown-valid/EPUB/package.opf
diff --git a/...tion-unknown-error/META-INF/container.xml → ...tion-unknown-valid/META-INF/container.xml b/...tion-unknown-error/META-INF/container.xml → ...tion-unknown-valid/META-INF/container.xml
diff --git a/...ion-unknown-error/META-INF/encryption.xml → ...ion-unknown-valid/META-INF/encryption.xml b/...ion-unknown-error/META-INF/encryption.xml → ...ion-unknown-valid/META-INF/encryption.xml
diff --git a/...pub/ocf-encryption-unknown-error/mimetype → ...pub/ocf-encryption-unknown-valid/mimetype b/...pub/ocf-encryption-unknown-error/mimetype → ...pub/ocf-encryption-unknown-valid/mimetype
diff --git a/src/test/resources/epub3/files/epub/ocf-obfuscation-not-cmt-error/EPUB/content_001.xhtml b/src/test/resources/epub3/files/epub/ocf-obfuscation-not-cmt-error/EPUB/content_001.xhtml
@@ -0,0 +1,11 @@
+<!DOCTYPE html>
+<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
+	<head>
+		<meta charset="utf-8"/>
+		<title>Minimal EPUB</title>
+	</head>
+	<body>
+		<h1>Loomings</h1>
+		<p>Call me Ishmael.</p>
+	</body>
+</html>
diff --git a/src/test/resources/epub3/files/epub/ocf-obfuscation-not-cmt-error/EPUB/nav.xhtml b/src/test/resources/epub3/files/epub/ocf-obfuscation-not-cmt-error/EPUB/nav.xhtml
@@ -0,0 +1,14 @@
+<!DOCTYPE html>
+<html xmlns="http://www.w3.org/1999/xhtml" xmlns:epub="http://www.idpf.org/2007/ops" xml:lang="en" lang="en">
+	<head>
+		<meta charset="utf-8"/>
+		<title>Minimal Nav</title>
+	</head>
+	<body>
+		<nav epub:type="toc">
+			<ol>
+				<li><a href="content_001.xhtml">content 001</a></li>
+			</ol>
+		</nav>
+	</body>
+</html>
diff --git a/src/test/resources/epub3/files/epub/ocf-obfuscation-not-cmt-error/EPUB/obfuscated-font.otf b/src/test/resources/epub3/files/epub/ocf-obfuscation-not-cmt-error/EPUB/obfuscated-font.otf
diff --git a/src/test/resources/epub3/files/epub/ocf-obfuscation-not-cmt-error/EPUB/package.opf b/src/test/resources/epub3/files/epub/ocf-obfuscation-not-cmt-error/EPUB/package.opf
@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<package xmlns="http://www.idpf.org/2007/opf" version="3.0" xml:lang="en" unique-identifier="q">
+<metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
+  <dc:title id="title">Minimal EPUB 3.0</dc:title>
+  <dc:language>en</dc:language>
+  <dc:identifier id="q">NOID</dc:identifier>
+  <meta property="dcterms:modified">2017-06-14T00:00:01Z</meta>
+</metadata>
+<manifest>
+  <item id="content_001"  href="content_001.xhtml" media-type="application/xhtml+xml"/>
+  <item id="nav"  href="nav.xhtml" media-type="application/xhtml+xml" properties="nav"/>
+  <item id="font" href="obfuscated-font.otf" media-type="font/opentype"/>
+</manifest>
+<spine>
+  <itemref idref="content_001" />
+</spine>
+</package>
diff --git a/src/test/resources/epub3/files/epub/ocf-obfuscation-not-cmt-error/META-INF/container.xml b/src/test/resources/epub3/files/epub/ocf-obfuscation-not-cmt-error/META-INF/container.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<container version="1.0" xmlns="urn:oasis:names:tc:opendocument:xmlns:container">
+	<rootfiles>
+		<rootfile full-path="EPUB/package.opf" media-type="application/oebps-package+xml"/>
+	</rootfiles>
+</container>
diff --git a/src/test/resources/epub3/files/epub/ocf-obfuscation-not-cmt-error/META-INF/encryption.xml b/src/test/resources/epub3/files/epub/ocf-obfuscation-not-cmt-error/META-INF/encryption.xml
@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<encryption xmlns="urn:oasis:names:tc:opendocument:xmlns:container">
+  <EncryptedData xmlns="http://www.w3.org/2001/04/xmlenc#">
+    <EncryptionMethod Algorithm="http://www.idpf.org/2008/embedding"/>
+    <CipherData>
+      <CipherReference URI="EPUB/obfuscated-font.otf"/>
+    </CipherData>
+  </EncryptedData>
+</encryption>
diff --git a/...s/epub/ocf-obfuscation-svg-valid/mimetype → ...ub/ocf-obfuscation-not-cmt-error/mimetype b/...s/epub/ocf-obfuscation-svg-valid/mimetype → ...ub/ocf-obfuscation-not-cmt-error/mimetype
diff --git a/...uscation-svg-valid/EPUB/content_001.xhtml → ...ion-not-font-error/EPUB/content_001.xhtml b/...uscation-svg-valid/EPUB/content_001.xhtml → ...ion-not-font-error/EPUB/content_001.xhtml
@@ -7,6 +7,5 @@
 	<body epub:type="bodymatter">
 		<h1>Loomings</h1>
 		<p>Call me Ishmael.</p>
-		<img src="emoji.svg" alt="a smiling emoji" />
 	</body>
 </html>
diff --git a/.../ocf-obfuscation-svg-valid/EPUB/emoji.svg → ...f-obfuscation-not-font-error/EPUB/doc.xml b/.../ocf-obfuscation-svg-valid/EPUB/emoji.svg → ...f-obfuscation-not-font-error/EPUB/doc.xml
diff --git a/.../ocf-obfuscation-svg-valid/EPUB/nav.xhtml → ...obfuscation-not-font-error/EPUB/nav.xhtml b/.../ocf-obfuscation-svg-valid/EPUB/nav.xhtml → ...obfuscation-not-font-error/EPUB/nav.xhtml
diff --git a/...cf-obfuscation-svg-valid/EPUB/package.opf → ...fuscation-not-font-error/EPUB/package.opf b/...cf-obfuscation-svg-valid/EPUB/package.opf → ...fuscation-not-font-error/EPUB/package.opf
@@ -9,7 +9,7 @@
 <manifest>
   <item id="content_001"  href="content_001.xhtml" media-type="application/xhtml+xml"/>
   <item id="nav"  href="nav.xhtml" media-type="application/xhtml+xml" properties="nav"/>
-  <item id="emoji" href="emoji.svg" media-type="image/svg+xml"/>
+  <item id="doc" href="doc.xml" media-type="application/xml"/>
 </manifest>
 <spine>
   <itemref idref="content_001" />

diff --git a/...uscation-svg-valid/META-INF/container.xml → ...ion-not-font-error/META-INF/container.xml b/...uscation-svg-valid/META-INF/container.xml → ...ion-not-font-error/META-INF/container.xml
diff --git a/...scation-svg-valid/META-INF/encryption.xml → ...on-not-font-error/META-INF/encryption.xml b/...scation-svg-valid/META-INF/encryption.xml → ...on-not-font-error/META-INF/encryption.xml
@@ -4,7 +4,7 @@
   <enc:EncryptedData>
     <enc:EncryptionMethod Algorithm="http://www.idpf.org/2008/embedding"/>
     <enc:CipherData>
-      <enc:CipherReference URI="EPUB/emoji.svg"/>
+      <enc:CipherReference URI="EPUB/doc.xml"/>
     </enc:CipherData>
   </enc:EncryptedData>
 </encryption>
diff --git a/src/test/resources/epub3/files/epub/ocf-obfuscation-not-font-error/mimetype b/src/test/resources/epub3/files/epub/ocf-obfuscation-not-font-error/mimetype
@@ -0,0 +1 @@
+application/epub+zip
diff --git a/src/test/resources/epub3/files/epub/ocf-obfuscation-valid/EPUB/package.opf b/src/test/resources/epub3/files/epub/ocf-obfuscation-valid/EPUB/package.opf
@@ -9,7 +9,7 @@
 <manifest>
   <item id="content_001"  href="content_001.xhtml" media-type="application/xhtml+xml"/>
   <item id="nav"  href="nav.xhtml" media-type="application/xhtml+xml" properties="nav"/>
-  <item id="font" href="obfuscated-font.otf" media-type="font/opentype"/>
+  <item id="font" href="obfuscated-font.otf" media-type="font/otf"/>
 </manifest>
 <spine>
   <itemref idref="content_001" />