Merge remote-tracking branch

'origin/GP-1192_dev747368_DWARF_PE--SQUASHED' (Closes #1267)

Ghidra/Features/Base/src/main/java/ghidra/app/util/bin/format/dwarf4/DWARFCompilationUnit.java

@@ -108,16 +108,20 @@ public class DWARFCompilationUnit {
 	 * from the debug_info section and the debug_abbr section and its compileUnit DIE (ie.
 	 * the first DIE right after the header).
 	 * <p>
-	 * Returns NULL if there was an ignorable error while reading the compilation unit (and
+	 * Returns {@code NULL} if there was an ignorable error while reading the compilation unit (and
 	 * leaves the input stream at the next compilation unit to read), otherwise throws
 	 * an IOException if there was an unrecoverable error.
+	 * <p>
+	 * Also returns {@code NULL} (and leaves the stream at EOF) if the remainder of the stream 
+	 * is filled with null bytes. 
 	 *
 	 * @param dwarfProgram the dwarf program.
 	 * @param debugInfoBR the debug info binary reader.
 	 * @param debugAbbrBR the debug abbreviation binary reader
 	 * @param cuNumber the compilation unit number
 	 * @param monitor the current task monitor
-	 * @return the read compilation unit.
+	 * @return the read compilation unit, or null if the compilation unit was bad/empty and should 
+	 * be ignored
 	 * @throws DWARFException if an invalid or unsupported DWARF version is read.
 	 * @throws IOException if the length of the compilation unit is invalid.
 	 * @throws CancelledException if the task has been canceled.
@@ -129,6 +133,19 @@ public static DWARFCompilationUnit readCompilationUnit(DWARFProgram dwarfProgram
 		long startOffset = debugInfoBR.getPointerIndex();
 		LengthResult lengthInfo =
 			DWARFUtil.readLength(debugInfoBR, dwarfProgram.getGhidraProgram());
+		if (lengthInfo.length == 0) {
+			if (isAllZerosUntilEOF(debugInfoBR)) {
+				// hack to handle trailing padding at end of section.  (similar to the check for
+				// unexpectedTerminator in readDIEs(), when padding occurs inside the bounds
+				// of the compile unit's range after the end of the root DIE's children)
+				debugInfoBR.setPointerIndex(debugInfoBR.length());
+				return null;
+			}
+			else {
+				throw new DWARFException(
+					"Invalid DWARF length 0 at 0x" + Long.toHexString(startOffset));
+			}
+		}
 
 		long endOffset = debugInfoBR.getPointerIndex() + lengthInfo.length;
 		short version = debugInfoBR.readNextShort();
@@ -177,6 +194,16 @@ else if (firstDIEOffset == endOffset) {
 		}
 	}
 
+	private static boolean isAllZerosUntilEOF(BinaryReader reader) throws IOException {
+		reader = reader.clone();
+		while (reader.getPointerIndex() < reader.length()) {
+			if (reader.readNextByte() != 0) {
+				return false;
+			}
+		}
+		return true;
+	}
+
 	/**
 	 * This ctor is public only for junit tests.  Do not use directly.
 	 * 

Ghidra/Features/Base/src/main/java/ghidra/app/util/bin/format/dwarf4/DWARFLine.java

@@ -15,11 +15,12 @@
  */
 package ghidra.app.util.bin.format.dwarf4;
 
-import java.io.File;
-import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 
+import java.io.File;
+import java.io.IOException;
+
 import org.apache.commons.io.FilenameUtils;
 
 import ghidra.app.util.bin.BinaryReader;
@@ -69,6 +70,10 @@ public static DWARFLine read(DIEAggregate diea) throws IOException, DWARFExcepti
 		LengthResult lengthInfo = DWARFUtil.readLength(reader, dProg.getGhidraProgram());
 		result.unit_length = lengthInfo.length;
 		result.format = lengthInfo.format;
+		if (result.unit_length == 0) {
+			throw new DWARFException(
+				"Invalid DWARFLine length 0 at 0x" + Long.toHexString(stmtListOffset));
+		}
 
 		// A version number for this line number information section
 		result.version = reader.readNextUnsignedShort();

Ghidra/Features/Base/src/main/java/ghidra/app/util/bin/format/dwarf4/DWARFUtil.java

@@ -15,13 +15,14 @@
  */
 package ghidra.app.util.bin.format.dwarf4;
 
-import java.io.IOException;
-import java.lang.reflect.Field;
-import java.lang.reflect.Modifier;
 import java.util.*;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
+import java.io.IOException;
+import java.lang.reflect.Field;
+import java.lang.reflect.Modifier;
+
 import ghidra.app.util.bin.BinaryReader;
 import ghidra.app.util.bin.format.dwarf4.attribs.DWARFAttributeValue;
 import ghidra.app.util.bin.format.dwarf4.attribs.DWARFNumericAttribute;
@@ -584,13 +585,13 @@ private LengthResult(long length, int format) {
 	 * 
 	 * @param reader {@link BinaryReader} stream to read from
 	 * @param program Ghidra {@link Program} 
-	 * @return new {@link LengthResult}, never null
+	 * @return new {@link LengthResult}, never null; length == 0 should be checked for and treated
+	 * specially
 	 * @throws IOException if io error
 	 * @throws DWARFException if invalid values
 	 */
 	public static LengthResult readLength(BinaryReader reader, Program program)
 			throws IOException, DWARFException {
-		long startOffset = reader.getPointerIndex();
 		long length = reader.readNextUnsignedInt();
 		int format;
 
@@ -617,8 +618,8 @@ else if (length == 0) {
 				format = DWARFCompilationUnit.DWARF_64;
 			}
 			else {
-				throw new DWARFException(
-					"Invalid DWARF length 0 at 0x" + Long.toHexString(startOffset));
+				// length 0 signals an error to caller
+				format = DWARFCompilationUnit.DWARF_32; // doesn't matter
 			}
 		}
 		else {

Ghidra/Features/Base/src/main/java/ghidra/app/util/bin/format/dwarf4/next/DWARFProgram.java

@@ -15,9 +15,10 @@
  */
 package ghidra.app.util.bin.format.dwarf4.next;
 
+import java.util.*;
+
 import java.io.Closeable;
 import java.io.IOException;
-import java.util.*;
 
 import org.apache.commons.collections4.ListValuedMap;
 import org.apache.commons.collections4.multimap.ArrayListValuedHashMap;
@@ -28,8 +29,7 @@
 import ghidra.app.util.bin.format.dwarf4.encoding.*;
 import ghidra.app.util.bin.format.dwarf4.expression.DWARFExpressionException;
 import ghidra.app.util.bin.format.dwarf4.next.sectionprovider.*;
-import ghidra.app.util.opinion.ElfLoader;
-import ghidra.app.util.opinion.MachoLoader;
+import ghidra.app.util.opinion.*;
 import ghidra.program.model.address.Address;
 import ghidra.program.model.address.AddressSet;
 import ghidra.program.model.data.CategoryPath;
@@ -67,15 +67,17 @@ public class DWARFProgram implements Closeable {
 	 * @return boolean true if program has DWARF info, false if not
 	 */
 	public static boolean isDWARF(Program program) {
-		String format = program.getExecutableFormat();
-
-		if (ElfLoader.ELF_NAME.equals(format) &&
-			DWARFSectionProviderFactory.createSectionProviderFor(program) != null) {
-			return true;
-		}
-		if (MachoLoader.MACH_O_NAME.equals(format) &&
-			DSymSectionProvider.getDSYMForProgram(program) != null) {
-			return true;
+		String format = Objects.requireNonNullElse(program.getExecutableFormat(), "");
+
+		switch (format) {
+			case ElfLoader.ELF_NAME:
+			case PeLoader.PE_NAME:
+				try (DWARFSectionProvider dsp =
+					DWARFSectionProviderFactory.createSectionProviderFor(program)) {
+					return dsp != null;
+				}
+			case MachoLoader.MACH_O_NAME:
+				return DSymSectionProvider.getDSYMForProgram(program) != null;
 		}
 		return false;
 	}