Fix opcode handling when reading DWARF line number programs (#482)

* Fix OpCode handling * update ReleaseHistory.md * fix ordering
microsoft · Sep 9, 2021 · 374c420 · 374c420
1 parent fbcdacb
commit 374c420
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Showing 3 changed files with 16 additions and 7 deletions.
diff --git a/src/BinaryParsers/ElfBinary/Dwarf/DwarfEnums.cs b/src/BinaryParsers/ElfBinary/Dwarf/DwarfEnums.cs
@@ -415,6 +415,9 @@ public enum DwarfAttribute
     /// </summary>
     public enum DwarfLineNumberStandardOpcode
     {
+        // Extended opcodes (0)
+        // Standard opcodes (1 to 12)
+        // Special opcodes (13 or greater)
         Extended = 0,
         Copy = 0x01,
         AdvancePc = 0x02,

diff --git a/src/BinaryParsers/ElfBinary/Dwarf/DwarfLineNumberProgram.cs b/src/BinaryParsers/ElfBinary/Dwarf/DwarfLineNumberProgram.cs
@@ -1,7 +1,6 @@
 // Copyright (c) Microsoft. All rights reserved.
 // Licensed under the MIT license. See LICENSE file in the project root for full license information.
 
-using System;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
@@ -193,6 +192,11 @@ private static List<DwarfFileInformation> ReadData(DwarfMemoryReader debugLine,
             byte lineRange = debugLine.ReadByte();
             byte operationCodeBase = debugLine.ReadByte();
 
+            if (operationCodeBase <= 0)
+            {
+                return new List<DwarfFileInformation>();
+            }
+
             // Read operation code lengths
             uint[] operationCodeLengths = new uint[operationCodeBase];
 
@@ -312,7 +316,11 @@ private static List<DwarfFileInformation> ReadData(DwarfMemoryReader debugLine,
                             break;
 
                         case DwarfLineNumberStandardOpcode.SetFile:
-                            state.File = files[(int)debugLine.LEB128() - 1];
+                            int index = (int)debugLine.LEB128() - 1;
+                            if (index >= 0 && index < files.Count)
+                            {
+                                state.File = files[index];
+                            }
                             break;
 
                         case DwarfLineNumberStandardOpcode.SetColumn:
@@ -348,12 +356,9 @@ private static List<DwarfFileInformation> ReadData(DwarfMemoryReader debugLine,
                             state.Isa = debugLine.LEB128();
                             break;
 
-                        case (DwarfLineNumberStandardOpcode)13:
-                            // when reading some dwarf debugline data, get OpCode 13 which is not in dwarf official document
-                            break;
-
                         default:
-                            throw new Exception($"Unsupported DwarfLineNumberStandardOpcode: {(DwarfLineNumberStandardOpcode)operationCode}");
+                            // Special opcodes(13 or greater)
+                            break;
                     }
                 }
             }

diff --git a/src/ReleaseHistory.md b/src/ReleaseHistory.md
@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+* BUGFIX: Fix opcode handling when reading DWARF line number programs. [#482](https://github.com/microsoft/binskim/pull/482)
 * BUGFIX: Fix exception `System.ArgumentException` when checking file format. [#481](https://github.com/microsoft/binskim/pull/481)
 * BUGFIX: Change compiler report rule to report all modules in file. [#476](https://github.com/microsoft/binskim/pull/476)
 * FEATURE: Add dialects to the reporting rules. [#475](https://github.com/microsoft/binskim/pull/475)