From 12058b79d7ba17902b90c3e777b10a8c4403fe5e Mon Sep 17 00:00:00 2001
From: Dan Engelbrecht <dan.engelbrecht@epicgames.com>
Date: Tue, 9 May 2023 14:50:41 +0200
Subject: Validate that entries points inside valid blocks at startup (#280)

* Separate initialization of block store from pruning of unknown blocks
* Validate that entries points inside valid blocks
---
 src/zenserver/cache/structuredcachestore.cpp | 48 +++++++++++++++++++++++++---
 1 file changed, 44 insertions(+), 4 deletions(-)

(limited to 'src/zenserver/cache/structuredcachestore.cpp')

diff --git a/src/zenserver/cache/structuredcachestore.cpp b/src/zenserver/cache/structuredcachestore.cpp
index 26e970073..99ca23407 100644
--- a/src/zenserver/cache/structuredcachestore.cpp
+++ b/src/zenserver/cache/structuredcachestore.cpp
@@ -1002,6 +1002,11 @@ ZenCacheDiskLayer::CacheBucket::OpenLog(const bool IsNew)
 		fs::remove_all(m_BlocksBasePath);
 	}
 
+	CreateDirectories(m_BucketDir);
+
+	std::unordered_map<uint32_t, uint64_t> BlockSizes =
+		m_BlockStore.Initialize(m_BlocksBasePath, MaxBlockSize, BlockStoreDiskLocation::MaxBlockIndex + 1);
+
 	uint64_t LogEntryCount = 0;
 	{
 		uint32_t IndexVersion = 0;
@@ -1023,12 +1028,11 @@ ZenCacheDiskLayer::CacheBucket::OpenLog(const bool IsNew)
 		}
 	}
 
-	CreateDirectories(m_BucketDir);
-
 	m_SlogFile.Open(LogPath, CasLogFile::Mode::kWrite);
 
 	std::vector<BlockStoreLocation> KnownLocations;
 	KnownLocations.reserve(m_Index.size());
+	std::vector<DiskIndexEntry> BadEntries;
 	for (const auto& Entry : m_Index)
 	{
 		size_t				 EntryIndex = Entry.second;
@@ -1041,10 +1045,46 @@ ZenCacheDiskLayer::CacheBucket::OpenLog(const bool IsNew)
 			continue;
 		}
 		const BlockStoreLocation& BlockLocation = Location.GetBlockLocation(m_PayloadAlignment);
-		KnownLocations.push_back(BlockLocation);
+
+		auto BlockIt = BlockSizes.find(BlockLocation.BlockIndex);
+		if (BlockIt == BlockSizes.end())
+		{
+			ZEN_WARN("Unknown block {} for entry {}", BlockLocation.BlockIndex, Entry.first.ToHexString());
+		}
+		else
+		{
+			uint64_t BlockSize = BlockIt->second;
+			if (BlockLocation.Offset + BlockLocation.Size > BlockSize)
+			{
+				ZEN_WARN("Range is outside of block {} for entry {}", BlockLocation.BlockIndex, Entry.first.ToHexString());
+			}
+			else
+			{
+				KnownLocations.push_back(BlockLocation);
+				continue;
+			}
+		}
+
+		DiskLocation NewLocation = Payload.Location;
+		NewLocation.Flags |= DiskLocation::kTombStone;
+		BadEntries.push_back(DiskIndexEntry{.Key = Entry.first, .Location = NewLocation});
 	}
 
-	m_BlockStore.Initialize(m_BlocksBasePath, MaxBlockSize, BlockStoreDiskLocation::MaxBlockIndex + 1, KnownLocations);
+	if (!BadEntries.empty())
+	{
+		m_SlogFile.Append(BadEntries);
+		m_SlogFile.Flush();
+
+		LogEntryCount += BadEntries.size();
+
+		for (const DiskIndexEntry& BadEntry : BadEntries)
+		{
+			m_Index.erase(BadEntry.Key);
+		}
+	}
+
+	m_BlockStore.Prune(KnownLocations);
+
 	if (IsNew || LogEntryCount > 0)
 	{
 		MakeIndexSnapshot();
-- 
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