[clang] Fix out-of-bounds memory access in ComputeLineNumbers

Differential Revision: https://reviews.llvm.org/D72409

1 files changed, 24 insertions, 0 deletions

diff --git a/clang/unittests/Basic/SourceManagerTest.cpp b/clang/unittests/Basic/SourceManagerTest.cpp
index 465f7a06f71..07c72e27f9f 100644
--- a/clang/unittests/Basic/SourceManagerTest.cpp
+++ b/clang/unittests/Basic/SourceManagerTest.cpp
@@ -20,7 +20,9 @@
 #include "clang/Lex/PreprocessorOptions.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/Config/llvm-config.h"
+#include "llvm/Support/Process.h"
 #include "gtest/gtest.h"
+#include <cstddef>
 
 using namespace clang;
 
@@ -241,6 +243,28 @@ TEST_F(SourceManagerTest, getInvalidBOM) {
             "UTF-32 (LE)");
 }
 
+// Regression test - there was an out of bound access for buffers not terminated by zero.
+TEST_F(SourceManagerTest, getLineNumber) {
+  const unsigned pageSize = llvm::sys::Process::getPageSizeEstimate();
+  std::unique_ptr<char[]> source(new char[pageSize]);
+  for(unsigned i = 0; i < pageSize; ++i) {
+    source[i] = 'a';
+  }
+
+  std::unique_ptr<llvm::MemoryBuffer> Buf =
+      llvm::MemoryBuffer::getMemBuffer(
+        llvm::MemoryBufferRef(
+          llvm::StringRef(source.get(), 3), "whatever"
+        ),
+        false
+      );
+
+  FileID mainFileID = SourceMgr.createFileID(std::move(Buf));
+  SourceMgr.setMainFileID(mainFileID);
+
+  ASSERT_NO_FATAL_FAILURE(SourceMgr.getLineNumber(mainFileID, 1, nullptr));
+}
+
 #if defined(LLVM_ON_UNIX)
 
 TEST_F(SourceManagerTest, getMacroArgExpandedLocation) {