reject known bad bucket names in structured cache (#452)v0.2.27-pre0

* added string_view helpers for ParseHexBytes/ParseHexNumber
* reject known bad buckets in structured cache put handler (32-character hex bucket names are rejected)
* also added bucket rejection logic to bucket discovery
* added rejected_writes stat to HttpStructuredCache

1 files changed, 32 insertions, 1 deletions

diff --git a/src/zenserver/cache/cachedisklayer.cpp b/src/zenserver/cache/cachedisklayer.cpp
index 894676d6a..177d37aa9 100644
--- a/src/zenserver/cache/cachedisklayer.cpp
+++ b/src/zenserver/cache/cachedisklayer.cpp
@@ -2145,17 +2145,26 @@ ZenCacheDiskLayer::DiscoverBuckets()
 
 	// Initialize buckets
 
+	std::vector<std::filesystem::path> BadBucketDirectories;
+
 	RwLock::ExclusiveLockScope _(m_Lock);
 
 	for (const std::filesystem::path& BucketPath : DirContent.Directories)
 	{
 		const std::string BucketName = PathToUtf8(BucketPath.stem());
-		// New bucket needs to be created
+
 		if (auto It = m_Buckets.find(BucketName); It != m_Buckets.end())
 		{
 			continue;
 		}
 
+		if (IsKnownBadBucketName(BucketName))
+		{
+			BadBucketDirectories.push_back(BucketPath);
+
+			continue;
+		}
+
 		auto		 InsertResult = m_Buckets.emplace(BucketName, std::make_unique<CacheBucket>(BucketName));
 		CacheBucket& Bucket		  = *InsertResult.first->second;
 
@@ -2176,6 +2185,28 @@ ZenCacheDiskLayer::DiscoverBuckets()
 		}
 		ZEN_INFO("Discovered bucket '{}'", BucketName);
 	}
+
+	for (const std::filesystem::path& BadBucketPath : BadBucketDirectories)
+	{
+		bool IsOk = false;
+
+		try
+		{
+			IsOk = DeleteDirectories(BadBucketPath);
+		}
+		catch (std::exception&)
+		{
+		}
+
+		if (IsOk)
+		{
+			ZEN_INFO("found bad bucket at '{}', deleted contents", BadBucketPath);
+		}
+		else
+		{
+			ZEN_WARN("bad bucket delete failed for '{}'", BadBucketPath);
+		}
+	}
 }
 
 bool