Verify sizes when trying to read a BitcodeAbbrevOp
Summary:
Make sure the abbrev operands are valid and that we can read/skip them
afterwards.
Bug found with AFL fuzz.
Reviewers: rafael
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D9030
llvm-svn: 235595
diff --git a/llvm/lib/Bitcode/Reader/BitstreamReader.cpp b/llvm/lib/Bitcode/Reader/BitstreamReader.cpp
index beaaf7a..ff37b8e 100644
--- a/llvm/lib/Bitcode/Reader/BitstreamReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitstreamReader.cpp
@@ -60,8 +60,10 @@
case BitCodeAbbrevOp::Blob:
llvm_unreachable("Should not reach here");
case BitCodeAbbrevOp::Fixed:
+ assert((unsigned)Op.getEncodingData() <= Cursor.MaxChunkSize);
return Cursor.Read((unsigned)Op.getEncodingData());
case BitCodeAbbrevOp::VBR:
+ assert((unsigned)Op.getEncodingData() <= Cursor.MaxChunkSize);
return Cursor.ReadVBR64((unsigned)Op.getEncodingData());
case BitCodeAbbrevOp::Char6:
return BitCodeAbbrevOp::DecodeChar6(Cursor.Read(6));
@@ -79,9 +81,11 @@
case BitCodeAbbrevOp::Blob:
llvm_unreachable("Should not reach here");
case BitCodeAbbrevOp::Fixed:
+ assert((unsigned)Op.getEncodingData() <= Cursor.MaxChunkSize);
Cursor.Read((unsigned)Op.getEncodingData());
break;
case BitCodeAbbrevOp::VBR:
+ assert((unsigned)Op.getEncodingData() <= Cursor.MaxChunkSize);
Cursor.ReadVBR64((unsigned)Op.getEncodingData());
break;
case BitCodeAbbrevOp::Char6:
@@ -264,6 +268,11 @@
continue;
}
+ if ((E == BitCodeAbbrevOp::Fixed || E == BitCodeAbbrevOp::VBR) &&
+ Data > MaxChunkSize)
+ report_fatal_error(
+ "Fixed or VBR abbrev record with size > MaxChunkData");
+
Abbv->Add(BitCodeAbbrevOp(E, Data));
} else
Abbv->Add(BitCodeAbbrevOp(E));