[llvm] r268084 - Fix crash in PDB when loading corrupt file.

[Zachary Turner via llvm-commits]

Author: zturner
Date: Fri Apr 29 13:09:19 2016
New Revision: 268084

URL: http://llvm.org/viewvc/llvm-project?rev=268084&view=rev
Log:
Fix crash in PDB when loading corrupt file.

There are probably hundreds of crashers we can find by fuzzing
more.  For now we do the simplest possible validation of the
block size.  Later, more complicated validations can verify that
other fields of the super block such as directory size, number
of blocks, agree with the size of the file etc.

Modified:
    llvm/trunk/lib/DebugInfo/PDB/Raw/PDBFile.cpp

Modified: llvm/trunk/lib/DebugInfo/PDB/Raw/PDBFile.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/DebugInfo/PDB/Raw/PDBFile.cpp?rev=268084&r1=268083&r2=268084&view=diff
==============================================================================
--- llvm/trunk/lib/DebugInfo/PDB/Raw/PDBFile.cpp (original)
+++ llvm/trunk/lib/DebugInfo/PDB/Raw/PDBFile.cpp Fri Apr 29 13:09:19 2016
@@ -123,6 +123,13 @@ std::error_code PDBFile::parseFileHeader
   Context->SB =
       reinterpret_cast<const SuperBlock *>(BufferRef.getBufferStart());
   const SuperBlock *SB = Context->SB;
+  switch (SB->BlockSize) {
+  case 512: case 1024: case 2048: case 4096:
+    break;
+  default:
+    // An invalid block size suggests a corrupt PDB file.
+    return std::make_error_code(std::errc::illegal_byte_sequence);
+  }
 
   // Make sure the file is sufficiently large to hold a super block.
   if (BufferRef.getBufferSize() < sizeof(SuperBlock))