From bc1a5b1393b08be6871835a25cb23f6528965650 Mon Sep 17 00:00:00 2001
From: Kelvin Zhang <zhangkelvin@google.com>
Date: Fri, 2 Dec 2022 09:50:44 -0800
Subject: [PATCH] Fix nullptr access when cow reader open fails

Bug: 260805150
Test: th
Change-Id: Id945cc4fa0fce141e3d52b8259241e22ba590ebd
---
 fs_mgr/libsnapshot/snapshot_writer.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs_mgr/libsnapshot/snapshot_writer.cpp b/fs_mgr/libsnapshot/snapshot_writer.cpp
index 6aad3d108..82a7fd7d6 100644
--- a/fs_mgr/libsnapshot/snapshot_writer.cpp
+++ b/fs_mgr/libsnapshot/snapshot_writer.cpp
@@ -93,6 +93,9 @@ bool CompressedSnapshotWriter::VerifyMergeOps() const noexcept {
 
 std::unique_ptr<FileDescriptor> CompressedSnapshotWriter::OpenReader() {
     auto cow = OpenCowReader();
+    if (cow == nullptr) {
+        return nullptr;
+    }
 
     auto reader = std::make_unique<CompressedSnapshotReader>();
     if (!reader->SetCow(std::move(cow))) {