diff --git a/common/utils.cc b/common/utils.cc
index 5dbb445..25df540 100644
--- a/common/utils.cc
+++ b/common/utils.cc
@@ -1040,6 +1040,11 @@
   return ErrorCode::kSuccess;
 }
 
+std::unique_ptr<android::base::MappedFile> GetReadonlyZeroBlock(size_t size) {
+  android::base::unique_fd fd{HANDLE_EINTR(open("/dev/zero", O_RDONLY))};
+  return android::base::MappedFile::FromFd(fd, 0, size, PROT_READ);
+}
+
 }  // namespace utils
 
 }  // namespace chromeos_update_engine
diff --git a/common/utils.h b/common/utils.h
index 4e78097..9ed0c7b 100644
--- a/common/utils.h
+++ b/common/utils.h
@@ -36,6 +36,7 @@
 #include <brillo/key_value_store.h>
 #include <brillo/secure_blob.h>
 
+#include "android-base/mapped_file.h"
 #include "update_engine/common/action.h"
 #include "update_engine/common/action_processor.h"
 #include "update_engine/common/constants.h"
@@ -357,6 +358,8 @@
 ErrorCode IsTimestampNewer(const std::string& old_version,
                            const std::string& new_version);
 
+std::unique_ptr<android::base::MappedFile> GetReadonlyZeroBlock(size_t size);
+
 }  // namespace utils
 
 // Utility class to close a file descriptor