[vrs} Relax limit on datalayout content blocks

Summary: In D66209820, we introduced a sanity check on datalayout sizes to make our fuzzer happy. However, we do have incredibly large archives that go beyond these limits. This diff increases the tolerance for huge varsize datalaout sections to what can actually fit in a record.

Reviewed By: finik

Differential Revision: D66338418

fbshipit-source-id: 8426ba613957bd78dc78cb292ed3f43078e10939

vrs/ContentBlockReader.cpp

@@ -20,6 +20,7 @@
 #include <logging/Log.h>
 #include <logging/Verify.h>
 
+#include <vrs/FileFormat.h>
 #include <vrs/helpers/FileMacros.h>
 #include <vrs/helpers/Throttler.h>
 #include <vrs/os/CompilerAttributes.h>
@@ -439,19 +440,20 @@ bool DataLayoutBlockReader::readBlock(
   // The size of the variable size buffer can be read from the var size index, so we read
   // the fixed size buffer first, extract the size of the var size data from the var size index,
   // so we can then read the var size buffer...
-  const size_t kMaxDataSize = 1024 * 1024 * 1024; // 1GB
+  const size_t kMaxFixedDataSize = 1024 * 1024 * 1024; // 1GB, arbitrary limit
+  const size_t kMaxRecordSize = 4 * 1024 * 1024 * 1024UL - sizeof(FileFormat::RecordHeader);
   DataLayout& layout = *blockLayout_;
   vector<int8_t>& fixedData = layout.getFixedData();
   size_t fixedDataSize = layout.getFixedDataSizeNeeded();
-  if (!XR_VERIFY(fixedDataSize <= kMaxDataSize)) {
+  if (!XR_VERIFY(fixedDataSize <= kMaxFixedDataSize)) {
     return false;
   }
   fixedData.resize(fixedDataSize);
   vector<int8_t>& varData = layout.getVarData();
   int readBlockStatus = record.reader->read(fixedData);
   if (readBlockStatus == 0) {
     size_t varDataSize = layout.getVarDataSizeFromIndex();
-    if (!XR_VERIFY(varDataSize <= kMaxDataSize)) {
+    if (!XR_VERIFY(fixedDataSize + varDataSize <= kMaxRecordSize)) {
       return false;
     }
     varData.resize(varDataSize);