Backport of:

From 2aaf593a9eb96d84fe3be740aca2810a97d95592 Mon Sep 17 00:00:00 2001
From: Philip Withnall <pwithnall@endlessos.org>
Date: Thu, 4 Feb 2021 13:50:37 +0000
Subject: [PATCH 07/11] gwin32: Use gsize internally in g_wcsdup()
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This allows it to handle strings up to length `G_MAXSIZE` — previously
it would overflow with such strings.

Update the several copies of it identically.

Signed-off-by: Philip Withnall <pwithnall@endlessos.org>
Helps: #2319
---
 gio/gwin32appinfo.c     | 33 ++++++++++++++++++++++++++-------
 gio/gwin32registrykey.c | 34 ++++++++++++++++++++++++++--------
 2 files changed, 52 insertions(+), 15 deletions(-)

diff --git a/gio/gwin32appinfo.c b/gio/gwin32appinfo.c
index 9f335b370..dd7a96a4a 100644
--- a/gio/gwin32appinfo.c
+++ b/gio/gwin32appinfo.c
@@ -464,15 +464,34 @@ static GWin32RegistryKey *applications_key;
 /* Watch this key */
 static GWin32RegistryKey *classes_root_key;
 
+static gsize
+g_utf16_len (const gunichar2 *str)
+{
+  gsize result;
+
+  for (result = 0; str[0] != 0; str++, result++)
+    ;
+
+  return result;
+}
+
 static gunichar2 *
-g_wcsdup (const gunichar2 *str, gssize str_size)
+g_wcsdup (const gunichar2 *str, gssize str_len)
 {
-  if (str_size == -1)
-    {
-      str_size = wcslen (str) + 1;
-      str_size *= sizeof (gunichar2);
-    }
-  return g_memdup (str, str_size);
+  gsize str_len_unsigned;
+  gsize str_size;
+
+  g_return_val_if_fail (str != NULL, NULL);
+
+  if (str_len < 0)
+    str_len_unsigned = g_utf16_len (str);
+  else
+    str_len_unsigned = (gsize) str_len;
+
+  g_assert (str_len_unsigned <= G_MAXSIZE / sizeof (gunichar2) - 1);
+  str_size = (str_len_unsigned + 1) * sizeof (gunichar2);
+
+  return g_memdup2 (str, str_size);
 }
 
 #define URL_ASSOCIATIONS L"HKEY_CURRENT_USER\\Software\\Microsoft\\Windows\\Shell\\Associations\\UrlAssociations\\"
diff --git a/gio/gwin32registrykey.c b/gio/gwin32registrykey.c
index 619fd48af..fbd65311a 100644
--- a/gio/gwin32registrykey.c
+++ b/gio/gwin32registrykey.c
@@ -127,16 +127,34 @@ typedef enum
   G_WIN32_REGISTRY_UPDATED_PATH = 1,
 } GWin32RegistryKeyUpdateFlag;
 
+static gsize
+g_utf16_len (const gunichar2 *str)
+{
+  gsize result;
+
+  for (result = 0; str[0] != 0; str++, result++)
+    ;
+
+  return result;
+}
+
 static gunichar2 *
-g_wcsdup (const gunichar2 *str,
-          gssize           str_size)
+g_wcsdup (const gunichar2 *str, gssize str_len)
 {
-  if (str_size == -1)
-    {
-      str_size = wcslen (str) + 1;
-      str_size *= sizeof (gunichar2);
-    }
-  return g_memdup (str, str_size);
+  gsize str_len_unsigned;
+  gsize str_size;
+
+  g_return_val_if_fail (str != NULL, NULL);
+
+  if (str_len < 0)
+    str_len_unsigned = g_utf16_len (str);
+  else
+    str_len_unsigned = (gsize) str_len;
+
+  g_assert (str_len_unsigned <= G_MAXSIZE / sizeof (gunichar2) - 1);
+  str_size = (str_len_unsigned + 1) * sizeof (gunichar2);
+
+  return g_memdup2 (str, str_size);
 }
 
 /**
-- 
2.30.1