Re: [PATCH 2/3] ShellPkg: Fix misuses of AllocateCopyPool

["Ni, Ruiyu" <ruiyu.ni@intel.com>]

2 comments below.

-----Original Message-----
From: Wang, Jian J 
Sent: Friday, November 3, 2017 12:58 PM
To: edk2-devel@lists.01.org
Cc: Carsey, Jaben <jaben.carsey@intel.com>; Ni, Ruiyu <ruiyu.ni@intel.com>; Bi, Dandan <dandan.bi@intel.com>
Subject: [PATCH 2/3] ShellPkg: Fix misuses of AllocateCopyPool

AllocateCopyPool(AllocationSize, *Buffer) will copy "AllocationSize" bytes of
memory from old "Buffer" to new allocated one. If "AllocationSize" is bigger
than size of "Buffer", heap memory overflow occurs during copy.

The solution is to allocate pool first then copy the necessary bytes to new
memory. This can avoid copying extra bytes from unknown memory range.

Cc: Jaben Carsey <jaben.carsey@intel.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Bi Dandan <dandan.bi@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
---
 ShellPkg/Application/Shell/Shell.c                                 | 4 +++-
 ShellPkg/Library/UefiShellBcfgCommandLib/UefiShellBcfgCommandLib.c | 6 ++++--
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/ShellPkg/Application/Shell/Shell.c b/ShellPkg/Application/Shell/Shell.c
index 5471930ba1..24a04ca323 100644
--- a/ShellPkg/Application/Shell/Shell.c
+++ b/ShellPkg/Application/Shell/Shell.c
@@ -1646,7 +1646,9 @@ ShellConvertVariables (
   //
   // now do the replacements...
   //
-  NewCommandLine1 = AllocateCopyPool(NewSize, OriginalCommandLine);
+  NewCommandLine1 = AllocatePool(NewSize);
+  ASSERT (NewCommandLine1 != NULL);
[Ray] 1. Please do not use assertion because there is NULL check in the below if-statement.
    The rule in ShellPkg is avoid using assertion.

+  CopyMem (NewCommandLine1, OriginalCommandLine, StrSize (OriginalCommandLine));
   NewCommandLine2 = AllocateZeroPool(NewSize);
   ItemTemp        = AllocateZeroPool(ItemSize+(2*sizeof(CHAR16)));
   if (NewCommandLine1 == NULL || NewCommandLine2 == NULL || ItemTemp == NULL) {
diff --git a/ShellPkg/Library/UefiShellBcfgCommandLib/UefiShellBcfgCommandLib.c b/ShellPkg/Library/UefiShellBcfgCommandLib/UefiShellBcfgCommandLib.c
index 1122c89b8b..5de62219b3 100644
--- a/ShellPkg/Library/UefiShellBcfgCommandLib/UefiShellBcfgCommandLib.c
+++ b/ShellPkg/Library/UefiShellBcfgCommandLib/UefiShellBcfgCommandLib.c
@@ -143,10 +143,11 @@ UpdateOptionalData(
     OriginalOptionDataSize += (*(UINT16*)(OriginalData + sizeof(UINT32)));
     OriginalOptionDataSize -= OriginalSize;
     NewSize = OriginalSize - OriginalOptionDataSize + DataSize;
-    NewData = AllocateCopyPool(NewSize, OriginalData);
+    NewData = AllocatePool(NewSize);
     if (NewData == NULL) {
       Status = EFI_OUT_OF_RESOURCES;
     } else {
+      CopyMem (NewData, OriginalData, OriginalSize - OriginalOptionDataSize);
       CopyMem(NewData + OriginalSize - OriginalOptionDataSize, Data, DataSize);
     }
   }
@@ -1120,11 +1121,12 @@ BcfgAddOpt(
         // Now we know how many EFI_INPUT_KEY structs we need to attach to the end of the EFI_KEY_OPTION struct.  
         // Re-allocate with the added information.
         //
-        KeyOptionBuffer = AllocateCopyPool(sizeof(EFI_KEY_OPTION) + (sizeof(EFI_INPUT_KEY) * NewKeyOption.KeyData.Options.InputKeyCount), &NewKeyOption);
+        KeyOptionBuffer = AllocatePool (sizeof(EFI_KEY_OPTION) + (sizeof(EFI_INPUT_KEY) * NewKeyOption.KeyData.Options.InputKeyCount));
         if (KeyOptionBuffer == NULL) {
           ShellPrintHiiEx(-1, -1, NULL, STRING_TOKEN (STR_GEN_NO_MEM), gShellBcfgHiiHandle, L"bcfg");  
           ShellStatus = SHELL_OUT_OF_RESOURCES;
         }
[Ray] 2. Should the above NULL check return?
+        CopyMem (KeyOptionBuffer, &NewKeyOption, sizeof(EFI_KEY_OPTION));
       }
       for (LoopCounter = 0 ; ShellStatus == SHELL_SUCCESS && LoopCounter < NewKeyOption.KeyData.Options.InputKeyCount; LoopCounter++) {
         //
-- 
2.14.1.windows.1