Merge pull request swiftlang#10596 from cachemeifyoucan/eng/PR-150386374-stable

[6.2][CAS] Fix an off-by-one error in CAS validation

Author: akyrtzi

llvm/lib/CAS/OnDiskGraphDB.cpp

@@ -966,7 +966,7 @@ Error OnDiskGraphDB::validate(bool Deep, HashingFuncT Hasher) const {
       llvm_unreachable("already handled");
     case TrieRecord::StorageKind::DataPool: {
       auto DataRecord = DataRecordHandle::get(DataPool.beginData(D.Offset));
-      if (DataRecord.getTotalSize() + D.Offset.get() >= DataPool.size())
+      if (DataRecord.getTotalSize() + D.Offset.get() > DataPool.size())
         return dataError("data record span passed the end of the data pool");
       for (auto InternRef : DataRecord.getRefs()) {
         auto Index = getIndexProxyFromRef(InternRef);

llvm/test/tools/llvm-cas/validation.test

@@ -1,6 +1,13 @@
 RUN: rm -rf %t
 RUN: mkdir %t
 
+# Ingest a blob which just fits inside the CAS data pool to make sure the validate passes.
+RUN: truncate -s 7 %t/file
+RUN: cat %t/file | \
+RUN:   llvm-cas --cas %t/cas  --make-blob \
+RUN:   --data -
+RUN: llvm-cas --cas %t/cas --validate --check-hash
+
 RUN: llvm-cas --cas %t/cas --ingest %S/Inputs > %t/cas.id
 RUN: llvm-cas --cas %t/cas --validate
 RUN: llvm-cas --cas %t/cas --validate --check-hash