From 8076b5e6f85667916a4ed50a191c4caef8da25b6 Mon Sep 17 00:00:00 2001
From: midipix <writeonce@midipix.org>
Date: Dec 08 2016 21:32:31 +0000
Subject: __ntapi_tt_open_physical_parent_directory(): fix device root dir detection.


---

diff --git a/src/fs/ntapi_tt_open_physical_parent_directory.c b/src/fs/ntapi_tt_open_physical_parent_directory.c
index e80a21a..d28eb1b 100644
--- a/src/fs/ntapi_tt_open_physical_parent_directory.c
+++ b/src/fs/ntapi_tt_open_physical_parent_directory.c
@@ -21,6 +21,7 @@ int32_t __stdcall __ntapi_tt_open_physical_parent_directory(
 	nt_oa				oa;
 	nt_iosb				iosb;
 	wchar16_t *			wch;
+	wchar16_t *			root;
 	nt_unicode_string *		path;
 	uint32_t			len;
 
@@ -35,17 +36,33 @@ int32_t __stdcall __ntapi_tt_open_physical_parent_directory(
 			buffer_size,
 			&len)))
 		return status;
-	else if (len == sizeof(nt_unicode_string))
+
+	/* integrity */
+	if (len == sizeof(nt_unicode_string))
 		return NT_STATUS_BAD_FILE_TYPE;
 
-	wch = path->buffer + (path->strlen / sizeof(uint16_t));
+	/* device root directory */
+	root = path->buffer;
+	wch  = path->buffer + (path->strlen / sizeof(uint16_t));
+
 
-	for (; (wch > path->buffer) && (wch[-1] != '\\'); wch--)
-		(void)0;
+	if ((root[0] != '\\')
+			|| (root[1] != 'D') || (root[2] != 'e')
+			|| (root[3] != 'v') || (root[4] != 'i')
+			|| (root[5] != 'c') || (root[6] != 'e')
+			|| (root[7] != '\\'))
+		return NT_STATUS_INTERNAL_ERROR;
 
-	if (wch == path->buffer)
+	for (root=&root[8]; (root<wch) && (*root!='\\'); )
+		root++;
+
+	if ((uint16_t)((++root - path->buffer) * sizeof(uint16_t)) == path->strlen)
 		return NT_STATUS_MORE_PROCESSING_REQUIRED;
 
+	/* physical parent directory path */
+	for (; (wch>root) && (wch[-1]!='\\'); )
+		wch--;
+
 	path->strlen = sizeof(uint16_t) * (uint16_t)(wch-path->buffer);
 	path->maxlen = 0;