From 454f4679ef838f866faf26e8f20c960ae5191795 Mon Sep 17 00:00:00 2001
From: Marc Mutz <marc.mutz@qt.io>
Date: Thu, 8 Sep 2022 16:26:01 +0200
Subject: [PATCH] qUncompress: make a narrowing conversion explicit

... and add an assertion. The assertion can only trigger if our
definition of MaxDecompressedSize is wrong.

Pick-to: 6.4 6.3 6.2
Task-number: QTBUG-104972
Change-Id: Ifa375f59fb6ff5e0324d2208f4c2882174f9a44d
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
---
 src/corelib/text/qbytearray.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/corelib/text/qbytearray.cpp b/src/corelib/text/qbytearray.cpp
index 826c0b2be0..f5b468ad6e 100644
--- a/src/corelib/text/qbytearray.cpp
+++ b/src/corelib/text/qbytearray.cpp
@@ -633,7 +633,8 @@ QByteArray qUncompress(const uchar* data, qsizetype nbytes)
     if (len > MaxDecompressedSize)
         return invalidCompressedData();
 
-    QByteArray::DataPointer d(QByteArray::Data::allocate(len));
+    Q_ASSERT(len <= size_t((std::numeric_limits<qsizetype>::max)()));
+    QByteArray::DataPointer d(QByteArray::Data::allocate(qsizetype(len)));
     if (d.data() == nullptr) // allocation failed
         return invalidCompressedData();