From 39a02e649d88ba226340607c5d92768b615d24f7 Mon Sep 17 00:00:00 2001
From: John Preston <johnprestonmail@gmail.com>
Date: Mon, 2 May 2022 15:36:34 +0400
Subject: [PATCH] Fix crash on invalid data in local cache.

---
 Telegram/SourceFiles/storage/serialize_document.cpp | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/Telegram/SourceFiles/storage/serialize_document.cpp b/Telegram/SourceFiles/storage/serialize_document.cpp
index 50e4c51ac..fef3bdd21 100644
--- a/Telegram/SourceFiles/storage/serialize_document.cpp
+++ b/Telegram/SourceFiles/storage/serialize_document.cpp
@@ -150,14 +150,17 @@ DocumentData *Document::readFromStreamHelper(
 		}
 	}
 
-	const auto storage = std::get_if<StorageFileLocation>(
-		&thumb->file().data);
 	if ((stream.status() != QDataStream::Ok)
 		|| (!dc && !access)
 		|| !thumb
-		|| !videoThumb
-		|| (thumb->valid()
-			&& (!storage || !storage->isDocumentThumbnail()))) {
+		|| !videoThumb) {
+		stream.setStatus(QDataStream::ReadCorruptData);
+		return nullptr;
+	}
+	const auto storage = std::get_if<StorageFileLocation>(
+		&thumb->file().data);
+	if (thumb->valid()
+		&& (!storage || !storage->isDocumentThumbnail())) {
 		stream.setStatus(QDataStream::ReadCorruptData);
 		// We can't convert legacy thumbnail location to modern, because
 		// size letter ('s' or 'm') is lost, it was not saved in legacy.