Add NULL pointer check before using a pointer to avoid possible
NULL pointer dereference.

Cc: Eric Dong <eric.dong@intel.com>
Cc: Hao Wu <hao.a.wu@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Dandan Bi <dandan.bi@intel.com>
---
 MdeModulePkg/Universal/SetupBrowserDxe/Setup.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/MdeModulePkg/Universal/SetupBrowserDxe/Setup.c b/MdeModulePkg/Universal/SetupBrowserDxe/Setup.c
index 48beeb6..c2cfa5c 100644
--- a/MdeModulePkg/Universal/SetupBrowserDxe/Setup.c
+++ b/MdeModulePkg/Universal/SetupBrowserDxe/Setup.c
@@ -1484,11 +1484,13 @@ BufferToValue (
     //
     // Other type of Questions
     //
     if (Question->QuestionReferToBitField) {
       Buffer = (UINT8 *)AllocateZeroPool (Question->StorageWidth);
-      ASSERT (Buffer != NULL);
+      if (Buffer == NULL) {
+        return EFI_OUT_OF_RESOURCES;
+      }
       Dst = Buffer;
     } else {
       Dst = (UINT8 *) &Question->HiiValue.Value;
     }
   }
@@ -1546,15 +1548,13 @@ BufferToValue (
     }
   }
 
   *StringPtr = TempChar;
 
-  if (Question->QuestionReferToBitField) {
+  if (Buffer != NULL && Question->QuestionReferToBitField) {
     GetBitsQuestionValue (Question, Buffer);
-    if (Buffer != NULL) {
-      FreePool (Buffer);
-    }
+    FreePool (Buffer);
   }
 
   return Status;
 }
 
-- 
1.9.5.msysgit.1

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Reviewed-by: Hao Wu <hao.a.wu@intel.com>


Best Regards,
Hao Wu


> -----Original Message-----
> From: Bi, Dandan
> Sent: Friday, September 22, 2017 9:57 AM
> To: edk2-devel@lists.01.org
> Cc: Dong, Eric; Wu, Hao A
> Subject: [patch] MdeModulePkg/SetupBrowser:Add NULL check before using a
> pointer
> 
> Add NULL pointer check before using a pointer to avoid possible
> NULL pointer dereference.
> 
> Cc: Eric Dong <eric.dong@intel.com>
> Cc: Hao Wu <hao.a.wu@intel.com>
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Dandan Bi <dandan.bi@intel.com>
> ---
>  MdeModulePkg/Universal/SetupBrowserDxe/Setup.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/MdeModulePkg/Universal/SetupBrowserDxe/Setup.c
> b/MdeModulePkg/Universal/SetupBrowserDxe/Setup.c
> index 48beeb6..c2cfa5c 100644
> --- a/MdeModulePkg/Universal/SetupBrowserDxe/Setup.c
> +++ b/MdeModulePkg/Universal/SetupBrowserDxe/Setup.c
> @@ -1484,11 +1484,13 @@ BufferToValue (
>      //
>      // Other type of Questions
>      //
>      if (Question->QuestionReferToBitField) {
>        Buffer = (UINT8 *)AllocateZeroPool (Question->StorageWidth);
> -      ASSERT (Buffer != NULL);
> +      if (Buffer == NULL) {
> +        return EFI_OUT_OF_RESOURCES;
> +      }
>        Dst = Buffer;
>      } else {
>        Dst = (UINT8 *) &Question->HiiValue.Value;
>      }
>    }
> @@ -1546,15 +1548,13 @@ BufferToValue (
>      }
>    }
> 
>    *StringPtr = TempChar;
> 
> -  if (Question->QuestionReferToBitField) {
> +  if (Buffer != NULL && Question->QuestionReferToBitField) {
>      GetBitsQuestionValue (Question, Buffer);
> -    if (Buffer != NULL) {
> -      FreePool (Buffer);
> -    }
> +    FreePool (Buffer);
>    }
> 
>    return Status;
>  }
> 
> --
> 1.9.5.msysgit.1

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