[DebugInfo] Don't crash when given invalid DWARFv5 line table prologue.

This patch replaces an assertion with an explicit check for the validity
of the FORM parameters. The assertion was triggered when the DWARFv5
line table contained a zero address size.

This fixes OSS-Fuzz Issue 4644
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=4644

Differential revision: https://reviews.llvm.org/D41615

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@321863 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/llvm/DebugInfo/DWARF/DWARFFormValue.h b/include/llvm/DebugInfo/DWARF/DWARFFormValue.h
index d320535..2c0a942 100644 (file)
--- a/include/llvm/DebugInfo/DWARF/DWARFFormValue.h
+++ b/include/llvm/DebugInfo/DWARF/DWARFFormValue.h
@@ -50,6 +50,8 @@ struct DWARFFormParams {
     }
     llvm_unreachable("Invalid Format value");
   }
+
+  explicit operator bool() const { return Version && AddrSize; }
 };
 
 class DWARFFormValue {

diff --git a/lib/DebugInfo/DWARF/DWARFDebugLine.cpp b/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
index e5ef4ea..861122c 100644 (file)
--- a/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
+++ b/lib/DebugInfo/DWARF/DWARFDebugLine.cpp
@@ -268,7 +268,7 @@ bool DWARFDebugLine::Prologue::parse(const DWARFDataExtractor &DebugLineData,
 
   if (getVersion() >= 5) {
     if (!parseV5DirFileTables(DebugLineData, OffsetPtr, EndPrologueOffset,
-                              getFormParams(), U, HasMD5, IncludeDirectories,
+                              FormParams, U, HasMD5, IncludeDirectories,
                               FileNames)) {
       fprintf(stderr,
               "warning: parsing line table prologue at 0x%8.8" PRIx64

diff --git a/lib/DebugInfo/DWARF/DWARFFormValue.cpp b/lib/DebugInfo/DWARF/DWARFFormValue.cpp
index 44886de..769ac37 100644 (file)
--- a/lib/DebugInfo/DWARF/DWARFFormValue.cpp
+++ b/lib/DebugInfo/DWARF/DWARFFormValue.cpp
@@ -64,8 +64,9 @@ DWARFFormValue::getFixedByteSize(dwarf::Form Form,
                                  const DWARFFormParams Params) {
   switch (Form) {
   case DW_FORM_addr:
-    assert(Params.Version && Params.AddrSize && "Invalid Params for form");
-    return Params.AddrSize;
+    if (Params)
+      return Params.AddrSize;
+    return None;
 
   case DW_FORM_block:          // ULEB128 length L followed by L bytes.
   case DW_FORM_block1:         // 1 byte length L followed by L bytes.
@@ -86,8 +87,9 @@ DWARFFormValue::getFixedByteSize(dwarf::Form Form,
     return None;
 
   case DW_FORM_ref_addr:
-    assert(Params.Version && Params.AddrSize && "Invalid Params for form");
-    return Params.getRefAddrByteSize();
+    if (Params)
+      return Params.getRefAddrByteSize();
+    return None;
 
   case DW_FORM_flag:
   case DW_FORM_data1:
@@ -118,8 +120,9 @@ DWARFFormValue::getFixedByteSize(dwarf::Form Form,
   case DW_FORM_line_strp:
   case DW_FORM_sec_offset:
   case DW_FORM_strp_sup:
-    assert(Params.Version && Params.AddrSize && "Invalid Params for form");
-    return Params.getDwarfOffsetByteSize();
+    if (Params)
+      return Params.getDwarfOffsetByteSize();
+    return None;
 
   case DW_FORM_data8:
   case DW_FORM_ref8:

diff --git a/test/DebugInfo/Inputs/invalid.linetable b/test/DebugInfo/Inputs/invalid.linetable
new file mode 100644 (file)
index 0000000..5df4139
Binary files /dev/null and b/test/DebugInfo/Inputs/invalid.linetable differ

diff --git a/test/DebugInfo/dwarfdump-invalid-line-table.test b/test/DebugInfo/dwarfdump-invalid-line-table.test
new file mode 100644 (file)
index 0000000..afcaec0
--- /dev/null
+++ b/test/DebugInfo/dwarfdump-invalid-line-table.test
@@ -0,0 +1,5 @@
+Verify that dwarfdump doesn't crash on invalid line table prologue.
+OSS-Fuzz Issue 4644 (https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=4644)
+
+RUN: llvm-dwarfdump --verbose %p/Inputs/invalid.linetable 2>&1 | FileCheck %s --check-prefix=INVALID-LINE-TABLE
+INVALID-LINE-TABLE: invalid directory or file table description