[patch] MdeModulePkg/HiiDatabase: clean the value before setting default string

[Dandan Bi <dandan.bi@intel.com>]

For string op-code, the default string may not exceed the
maximum size, so when generating <AltResp> string, we should
clean the value before setting the default string.

https://bugzilla.tianocore.org/show_bug.cgi?id=375

Cc: Eric Dong <eric.dong@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Dandan Bi <dandan.bi@intel.com>
---
 MdeModulePkg/Universal/HiiDatabaseDxe/ConfigRouting.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/MdeModulePkg/Universal/HiiDatabaseDxe/ConfigRouting.c b/MdeModulePkg/Universal/HiiDatabaseDxe/ConfigRouting.c
index d547f42..1878106 100644
--- a/MdeModulePkg/Universal/HiiDatabaseDxe/ConfigRouting.c
+++ b/MdeModulePkg/Universal/HiiDatabaseDxe/ConfigRouting.c
@@ -1,9 +1,9 @@
 /** @file
 Implementation of interfaces function for EFI_HII_CONFIG_ROUTING_PROTOCOL.
 
-Copyright (c) 2007 - 2016, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2007 - 2017, Intel Corporation. All rights reserved.<BR>
 This program and the accompanying materials
 are licensed and made available under the terms and conditions of the BSD License
 which accompanies this distribution.  The full text of the license may be found at
 http://opensource.org/licenses/bsd-license.php
 
@@ -3696,21 +3696,29 @@ GenerateAltConfigResp (
         // Convert Value to a hex string in "%x" format
         // NOTE: This is in the opposite byte that GUID and PATH use
         //
         if (BlockData->OpCode == EFI_IFR_STRING_OP){
           DefaultString   = InternalGetString(HiiHandle, DefaultValueData->Value.string);
-          TmpBuffer = (UINT8 *) DefaultString;
+          TmpBuffer = AllocateZeroPool (Width);
+          ASSERT (TmpBuffer != NULL);
+          if (DefaultString != NULL) {
+            CopyMem (TmpBuffer, (UINT8 *) DefaultString, StrLen(DefaultString)* sizeof (CHAR16));
+          }
         } else {
           TmpBuffer = (UINT8 *) &(DefaultValueData->Value);
         }
         for (; Width > 0 && (TmpBuffer != NULL); Width--) {
           StringPtr += UnicodeValueToString (StringPtr, PREFIX_ZERO | RADIX_HEX, TmpBuffer[Width - 1], 2);
         }
         if (DefaultString != NULL){
           FreePool(DefaultString);
           DefaultString = NULL;
         }
+        if (BlockData->OpCode == EFI_IFR_STRING_OP && TmpBuffer != NULL) {
+          FreePool(TmpBuffer);
+          TmpBuffer  = NULL;
+        }
       }
     }
   }
 
   HiiToLower (*DefaultAltCfgResp);
-- 
1.9.5.msysgit.1