From d8c79c5d2a44b4c49f85d243f613bc9b90c80575 Mon Sep 17 00:00:00 2001
From: Pengfei <zhupf321@gmail.com>
Date: Tue, 27 Jul 2021 19:48:33 +0800
Subject: [PATCH] Critical bug fix

---
 src/core/ncch/ncch_container.cpp | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/core/ncch/ncch_container.cpp b/src/core/ncch/ncch_container.cpp
index d16b334..5183ce2 100644
--- a/src/core/ncch/ncch_container.cpp
+++ b/src/core/ncch/ncch_container.cpp
@@ -500,8 +500,20 @@ ResultStatus NCCHContainer::DecryptToFile(std::shared_ptr<FileUtil::IOFile> dest
             return false;
         }
         ASSERT_MSG(written <= offset, "Offsets are not in increasing order");
+
+        // Zero out the gap manually to ensure correct hashes when used with CIAs, etc.
+        const std::array<u8, 1024> zeroes{};
+        std::size_t zeroes_left = offset - written;
+        while (zeroes_left > 0) {
+            const auto to_write = std::min(zeroes.size(), zeroes_left);
+            if (dest_file->WriteBytes(zeroes.data(), to_write) != to_write) {
+                LOG_ERROR(Core, "Could not write zeroes before {}", name);
+                return false;
+            }
+            zeroes_left -= to_write;
+        }
+
         file->Seek(offset, SEEK_SET);
-        dest_file->Seek(offset, SEEK_SET);
 
         if (aborted.exchange(false)) {
             return false;