[lld] 5279f96 - [MachO] Fix detecting malformed DWARF.

[Igor Kudrin via llvm-commits]

Author: Igor Kudrin
Date: 2019-12-17T15:03:23+07:00
New Revision: 5279f96577af1457a973c071ec5ee3554c9f6cbe

URL: https://github.com/llvm/llvm-project/commit/5279f96577af1457a973c071ec5ee3554c9f6cbe
DIFF: https://github.com/llvm/llvm-project/commit/5279f96577af1457a973c071ec5ee3554c9f6cbe.diff

LOG: [MachO] Fix detecting malformed DWARF.

This fixes an invalid constant used to detect the reserved range when
reading the compilation unit header. See also: D64622 and D65039.

Differential Revision: https://reviews.llvm.org/D71546

Added: 
    

Modified: 
    lld/lib/ReaderWriter/MachO/MachONormalizedFileToAtoms.cpp

Removed: 
    


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diff  --git a/lld/lib/ReaderWriter/MachO/MachONormalizedFileToAtoms.cpp b/lld/lib/ReaderWriter/MachO/MachONormalizedFileToAtoms.cpp
index 0163c90189fd..6f294b1ecd0f 100644
--- a/lld/lib/ReaderWriter/MachO/MachONormalizedFileToAtoms.cpp
+++ b/lld/lib/ReaderWriter/MachO/MachONormalizedFileToAtoms.cpp
@@ -879,11 +879,11 @@ readCompUnit(const NormalizedFile &normalizedFile,
   llvm::dwarf::DwarfFormat Format = llvm::dwarf::DwarfFormat::DWARF32;
   auto infoData = dataExtractorFromSection(normalizedFile, info);
   uint32_t length = infoData.getU32(&offset);
-  if (length == 0xffffffff) {
+  if (length == llvm::dwarf::DW_LENGTH_DWARF64) {
     Format = llvm::dwarf::DwarfFormat::DWARF64;
     infoData.getU64(&offset);
   }
-  else if (length > 0xffffff00)
+  else if (length >= llvm::dwarf::DW_LENGTH_lo_reserved)
     return llvm::make_error<GenericError>("Malformed DWARF in " + path);
 
   uint16_t version = infoData.getU16(&offset);