From 90028919e4ca20cc6ff04fc2d1114c928d6f0260 Mon Sep 17 00:00:00 2001
From: midipix <writeonce@midipix.org>
Date: Jun 29 2016 23:16:44 +0000
Subject: __ntapi_tt_istat: refactor, explicit string comparison.


---

diff --git a/src/fs/ntapi_tt_istat.c b/src/fs/ntapi_tt_istat.c
index bd1b92d..bdfa09f 100644
--- a/src/fs/ntapi_tt_istat.c
+++ b/src/fs/ntapi_tt_istat.c
@@ -26,7 +26,6 @@ int32_t __stdcall __ntapi_tt_istat(
 	nt_oa			oa;
 	nt_iosb			iosb;
 	nt_unicode_string *	sdev;
-	uint32_t		hash;
 	wchar16_t *		wch;
 	wchar16_t *		wch_mark;
 
@@ -45,15 +44,15 @@ int32_t __stdcall __ntapi_tt_istat(
 		oa.sec_qos = 0;
 
 		/* open file/folder */
-		status = __ntapi->zw_open_file(
-			&hfile,
-			NT_SEC_SYNCHRONIZE | NT_FILE_READ_ATTRIBUTES | NT_FILE_READ_ACCESS,
-			&oa,
-			&iosb,
-			NT_FILE_SHARE_READ | NT_FILE_SHARE_WRITE,
-			open_options | NT_FILE_SYNCHRONOUS_IO_ALERT);
-
-		if (status != NT_STATUS_SUCCESS)
+		if ((status = __ntapi->zw_open_file(
+				&hfile,
+				NT_SEC_SYNCHRONIZE
+					| NT_FILE_READ_ATTRIBUTES
+					| NT_FILE_READ_ACCESS,
+				&oa,
+				&iosb,
+				NT_FILE_SHARE_READ | NT_FILE_SHARE_WRITE,
+				open_options | NT_FILE_SYNCHRONOUS_IO_ALERT)))
 			return status;
 
 		istat->flags_out = NT_STAT_NEW_HANDLE;
@@ -63,60 +62,57 @@ int32_t __stdcall __ntapi_tt_istat(
 	istat->flags_in = flags;
 
 	/* file index number */
-	status = __ntapi->zw_query_information_file(
-		hfile,
-		&iosb,
-		&istat->fii,
-		sizeof(istat->fii),
-		NT_FILE_INTERNAL_INFORMATION);
-
-	if (status != NT_STATUS_SUCCESS)
+	if ((status = __ntapi->zw_query_information_file(
+			hfile,
+			&iosb,
+			&istat->fii,
+			sizeof(istat->fii),
+			NT_FILE_INTERNAL_INFORMATION)))
 		return status;
 
 	/* attributes & reparse tag information */
-	status = __ntapi->zw_query_information_file(
-		hfile,
-		&iosb,
-		&istat->ftagi,
-		sizeof(istat->ftagi),
-		NT_FILE_ATTRIBUTE_TAG_INFORMATION);
-
-	if (status != NT_STATUS_SUCCESS)
+	if ((status = __ntapi->zw_query_information_file(
+			hfile,
+			&iosb,
+			&istat->ftagi,
+			sizeof(istat->ftagi),
+			NT_FILE_ATTRIBUTE_TAG_INFORMATION)))
 		return status;
 
-	/* TODO: consolidate with statfs */
 	/* system-unique device name */
-	iosb.info = 0;
-	status = __ntapi->zw_query_object(
-		hfile,
-		NT_OBJECT_NAME_INFORMATION,
-		buffer,
-		buffer_size,
-		(uint32_t *)&iosb.info);
-
-	if (status != NT_STATUS_SUCCESS)
+	if ((status = __ntapi->zw_query_object(
+			hfile,
+			NT_OBJECT_NAME_INFORMATION,
+			buffer,
+			buffer_size,
+			(uint32_t *)&iosb.info)))
 		return status;
 
 	sdev = (nt_unicode_string *)buffer;
+	wch  = sdev->buffer;
 
 	if (sdev->strlen < __DEVICE_PATH_PREFIX_LEN)
 		return NT_STATUS_INVALID_HANDLE;
 
-	hash = __ntapi->tt_buffer_crc32(
-		0,
-		sdev->buffer,
-		__DEVICE_PATH_PREFIX_LEN);
-
-	if (hash != __DEVICE_PATH_PREFIX_HASH)
+	if ((wch[0] != '\\')
+			|| (wch[1] != 'D')
+			|| (wch[2] != 'e')
+			|| (wch[3] != 'v')
+			|| (wch[4] != 'i')
+			|| (wch[5] != 'c')
+			|| (wch[6] != 'e')
+			|| (wch[7] != '\\'))
 		return NT_STATUS_INVALID_HANDLE;
 
-	wch_mark = sdev->buffer + __DEVICE_PATH_PREFIX_LEN/sizeof(wchar16_t);
-	wch = wch_mark;
-	while (*wch != '\\') wch++;
-	istat->dev_name_strlen = (uint16_t)((wch - sdev->buffer) * sizeof(uint16_t));
+	wch_mark = &wch[8];
+	wch      = wch_mark;
 
-	istat->dev_name_hash = __ntapi->tt_buffer_crc32(
-		hash,
+	while (*wch != '\\')
+		wch++;
+
+	istat->dev_name_strlen = (uint16_t)((wch - sdev->buffer) * sizeof(uint16_t));
+	istat->dev_name_hash   = __ntapi->tt_buffer_crc32(
+		__DEVICE_PATH_PREFIX_HASH,
 		wch_mark,
 		(uintptr_t)wch - (uintptr_t)wch_mark);