Backport alternative class reading method for invalid class CRCs

src/main/java/me/coley/recaf/workspace/JarResource.java

@@ -6,6 +6,7 @@
 import java.nio.file.Path;
 import java.util.*;
 import java.util.zip.ZipEntry;
+import java.util.zip.ZipException;
 import java.util.zip.ZipFile;
 import java.util.zip.ZipInputStream;
 
@@ -34,21 +35,49 @@ protected Map<String, byte[]> loadClasses() throws IOException {
 		ByteArrayOutputStream out = new ByteArrayOutputStream();
 		byte[] buffer = new byte[8192];
 		EntryLoader loader = getEntryLoader();
-		ZipInputStream zis = new ZipInputStream(new FileInputStream(getPath().toFile()));
-		ZipEntry entry;
-		while ((entry = zis.getNextEntry()) != null) {
-			// verify entries are classes and valid files
-			// - skip intentional garbage / zip file abnormalities
-			if (shouldSkip(entry.getName()))
-				continue;
-			if (loader.isValidClassEntry(entry)) {
+
+		try {
+			ZipInputStream zis = new ZipInputStream(new FileInputStream(getPath().toFile()));
+			ZipEntry entry;
+
+			while ((entry = zis.getNextEntry()) != null) {
+				// verify entries are classes and valid files
+				// - skip intentional garbage / zip file abnormalities
+				if (shouldSkip(entry.getName()))
+					continue;
+				if (!loader.isValidClassEntry(entry))
+					continue;
+
 				out.reset();
 				byte[] in = IOUtil.toByteArray(zis, out, buffer);
+
 				// There is no possible way a "class" under 30 bytes is valid
 				if (in.length < 30)
 					continue;
+
 				loader.onClass(entry.getName(), in);
 			}
+		} catch (ZipException e) {
+			if (e.getMessage().contains("invalid entry CRC")) {
+				// "ZipFile"/"JarFile" reads the entire ZIP file structure before letting us do any entry parsing.
+				// This may not always be ideal, but this way has one major bonus. It totally ignores CRC validity.
+				// It also ignores a few other zip entry values.
+				// Since somebody can intentionally write bogus data there to crash "ZipInputStream" this way works.
+				ZipFile zf = new ZipFile(getPath().toString());
+				Enumeration<? extends ZipEntry> entries = zf.entries();
+				while (entries.hasMoreElements()) {
+					ZipEntry entry = entries.nextElement();
+
+					if (shouldSkip(entry.getName()))
+						continue;
+					if (!loader.isValidClassEntry(entry))
+						continue;
+
+					InputStream zis = zf.getInputStream(entry);
+					byte[] in = IOUtil.toByteArray(zis);
+					loader.onClass(entry.getName(), in);
+				}
+			}
 		}
 		loader.finishClasses();
 		return loader.getClasses();