ShellPkg/Type.c: Add value check before (LoopVar - 1)

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1964

If the file begin with single line Feed ('\n'), then
"AsciiChar == '\n' && ((CHAR8*)Buffer)[LoopVar-1] != '\r'"
would cause a underflow. Add this condition
"(AsciiChar == '\n' && LoopVar == 0)" before it to make sure
(LoopVar - 1) would never encounter a underflow.

Same change in Unicode section.

Cc: Jaben Carsey <jaben.carsey@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Andrew Fish <afish@apple.com>
Signed-off-by: Zhichao Gao <zhichao.gao@intel.com>
Reviewed-by: Jaben Carsey <jaben.carsey@intel.com>
Reviewed-by: Andrew Fish <afish@apple.com>
This commit is contained in:
Zhichao Gao 2019-07-15 14:11:49 +08:00 committed by Jaben Carsey
parent 5d3ef15da7
commit ef2360569d
1 changed files with 13 additions and 11 deletions

View File

@ -2,7 +2,7 @@
Main file for Type shell level 3 function.
(C) Copyright 2013-2015 Hewlett-Packard Development Company, L.P.<BR>
Copyright (c) 2009 - 2018, Intel Corporation. All rights reserved. <BR>
Copyright (c) 2009 - 2019, Intel Corporation. All rights reserved. <BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
@ -78,12 +78,13 @@ TypeFileByHandle (
// Allow Line Feed (LF) (0xA) & Carriage Return (CR) (0xD)
// characters to be displayed as is.
//
if (AsciiChar == '\n' && ((CHAR8*)Buffer)[LoopVar-1] != '\r') {
if ((AsciiChar == '\n' && LoopVar == 0) ||
(AsciiChar == '\n' && ((CHAR8*)Buffer)[LoopVar-1] != '\r')) {
//
// In case Line Feed (0xA) is encountered & Carriage Return (0xD)
// was not the previous character, print CR and LF. This is because
// Shell 2.0 requires carriage return with line feed for displaying
// each new line from left.
// In case file begin with single line Feed or Line Feed (0xA) is
// encountered & Carriage Return (0xD) was not previous character,
// print CR and LF. This is because Shell 2.0 requires carriage
// return with line feed for displaying each new line from left.
//
ShellPrintEx (-1, -1, L"\r\n");
continue;
@ -121,12 +122,13 @@ TypeFileByHandle (
// Allow Line Feed (LF) (0xA) & Carriage Return (CR) (0xD)
// characters to be displayed as is.
//
if (Ucs2Char == '\n' && ((CHAR16*)Buffer)[LoopVar-1] != '\r') {
if ((Ucs2Char == '\n' && LoopVar == 0) ||
(Ucs2Char == '\n' && ((CHAR16*)Buffer)[LoopVar-1] != '\r')) {
//
// In case Line Feed (0xA) is encountered & Carriage Return (0xD)
// was not the previous character, print CR and LF. This is because
// Shell 2.0 requires carriage return with line feed for displaying
// each new line from left.
// In case file begin with single line Feed or Line Feed (0xA) is
// encountered & Carriage Return (0xD) was not previous character,
// print CR and LF. This is because Shell 2.0 requires carriage
// return with line feed for displaying each new line from left.
//
ShellPrintEx (-1, -1, L"\r\n");
continue;