Re: [Patch] [UDK2017] SecurityPkg OpalPasswordSupportLib: Add check to avoid potential buffer overflow.

["Dong, Eric" <eric.dong@intel.com>]

Hi Hao & Jiewen,

This patch has been verified by the original reporter, also pass regression test done by myself.

Thanks,
Eric

> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of Eric
> Dong
> Sent: Tuesday, July 31, 2018 1:16 PM
> To: edk2-devel@lists.01.org
> Cc: Wu, Hao A <hao.a.wu@intel.com>; Yao, Jiewen <jiewen.yao@intel.com>
> Subject: [edk2] [Patch] [UDK2017] SecurityPkg OpalPasswordSupportLib: Add
> check to avoid potential buffer overflow.
> 
> Current code not check the CommunicationBuffer size before use it. Attacker
> can read beyond the end of the (untrusted) commbuffer into controlled
> memory. Attacker can get access outside of valid SMM memory regions. This
> patch add check before use it.
> 
> Contributed-under: TianoCore Contribution Agreement 1.0
> Signed-off-by: Eric Dong <eric.dong@intel.com>
> Cc: Yao Jiewen <jiewen.yao@intel.com>
> Cc: Wu Hao <hao.a.wu@intel.com>
> ---
>  .../Include/Library/OpalPasswordSupportLib.h       |  3 +-
>  .../OpalPasswordSupportLib.c                       | 55 +++++++++++++++-------
>  .../OpalPasswordSupportNotify.h                    |  2 +-
>  .../Tcg/Opal/OpalPasswordSmm/OpalPasswordSmm.h     |  6 +--
>  4 files changed, 42 insertions(+), 24 deletions(-)
> 
> diff --git a/SecurityPkg/Include/Library/OpalPasswordSupportLib.h
> b/SecurityPkg/Include/Library/OpalPasswordSupportLib.h
> index e616c763f0..ad45e9e3b7 100644
> --- a/SecurityPkg/Include/Library/OpalPasswordSupportLib.h
> +++ b/SecurityPkg/Include/Library/OpalPasswordSupportLib.h
> @@ -19,6 +19,7 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY
> KIND, EITHER EXPRESS OR IMPLIED.
>  #include <Protocol/DevicePath.h>
>  #include <Library/TcgStorageOpalLib.h>
> 
> +#define OPAL_PASSWORD_MAX_LENGTH         32
> 
>  #pragma pack(1)
> 
> @@ -76,7 +77,7 @@ typedef struct {
>  typedef struct {
>    LIST_ENTRY                 Link;
> 
> -  UINT8                      Password[32];
> +  UINT8                      Password[OPAL_PASSWORD_MAX_LENGTH];
>    UINT8                      PasswordLength;
> 
>    EFI_DEVICE_PATH_PROTOCOL   OpalDevicePath;
> diff --git
> a/SecurityPkg/Library/OpalPasswordSupportLib/OpalPasswordSupportLib.c
> b/SecurityPkg/Library/OpalPasswordSupportLib/OpalPasswordSupportLib.c
> index 837582359e..e377e9ca79 100644
> --- a/SecurityPkg/Library/OpalPasswordSupportLib/OpalPasswordSupportLib.c
> +++ b/SecurityPkg/Library/OpalPasswordSupportLib/OpalPasswordSupportLib.
> +++ c
> @@ -14,8 +14,6 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY
> KIND, EITHER EXPRESS OR IMPLIED.
> 
>  #include "OpalPasswordSupportNotify.h"
> 
> -#define OPAL_PASSWORD_MAX_LENGTH         32
> -
>  LIST_ENTRY           mDeviceList = INITIALIZE_LIST_HEAD_VARIABLE
> (mDeviceList);
>  BOOLEAN              gInSmm = FALSE;
>  EFI_GUID             gOpalPasswordNotifyProtocolGuid =
> OPAL_PASSWORD_NOTIFY_PROTOCOL_GUID;
> @@ -663,34 +661,53 @@ SmmOpalPasswordHandler (
>    EFI_STATUS                        Status;
>    OPAL_SMM_COMMUNICATE_HEADER       *SmmFunctionHeader;
>    UINTN                             TempCommBufferSize;
> -  UINT8                             *NewPassword;
> -  UINT8                             PasswordLength;
> -  EFI_DEVICE_PATH_PROTOCOL          *DevicePath;
> +  UINTN                             RemainedDevicePathSize;
> +  OPAL_COMM_DEVICE_LIST             *DeviceBuffer;
> 
>    if (CommBuffer == NULL || CommBufferSize == NULL) {
>      return EFI_SUCCESS;
>    }
> 
> +  Status = EFI_SUCCESS;
> +  DeviceBuffer = NULL;
> +
>    TempCommBufferSize = *CommBufferSize;
>    if (TempCommBufferSize < OFFSET_OF
> (OPAL_SMM_COMMUNICATE_HEADER, Data)) {
>      return EFI_SUCCESS;
>    }
> -
> -  Status   = EFI_SUCCESS;
> -  SmmFunctionHeader     = (OPAL_SMM_COMMUNICATE_HEADER
> *)CommBuffer;
> -
> -  DevicePath = &((OPAL_COMM_DEVICE_LIST*)(SmmFunctionHeader-
> >Data))->OpalDevicePath;
> -  PasswordLength = ((OPAL_COMM_DEVICE_LIST*)(SmmFunctionHeader-
> >Data))->PasswordLength;
> -  NewPassword = ((OPAL_COMM_DEVICE_LIST*)(SmmFunctionHeader-
> >Data))->Password;
> +  SmmFunctionHeader = (OPAL_SMM_COMMUNICATE_HEADER
> *)CommBuffer;
> 
>    switch (SmmFunctionHeader->Function) {
>      case SMM_FUNCTION_SET_OPAL_PASSWORD:
> -        if (OpalPasswordIsFullZero (NewPassword) || PasswordLength == 0) {
> -          Status = EFI_INVALID_PARAMETER;
> -          goto EXIT;
> -        }
> +      if (TempCommBufferSize <= OFFSET_OF
> (OPAL_SMM_COMMUNICATE_HEADER, Data) + OFFSET_OF
> (OPAL_COMM_DEVICE_LIST, OpalDevicePath)) {
> +        return EFI_SUCCESS;
> +      }
> +
> +      DeviceBuffer = AllocateCopyPool (TempCommBufferSize - OFFSET_OF
> (OPAL_SMM_COMMUNICATE_HEADER, Data), SmmFunctionHeader->Data);
> +      if (DeviceBuffer == NULL) {
> +        Status = EFI_OUT_OF_RESOURCES;
> +        goto EXIT;
> +      }
> 
> -        Status = OpalSavePasswordToSmm (DevicePath, NewPassword,
> PasswordLength);
> +      //
> +      // Validate the DevicePath.
> +      //
> +      RemainedDevicePathSize = TempCommBufferSize - OFFSET_OF
> (OPAL_SMM_COMMUNICATE_HEADER, Data)
> +                                    - OFFSET_OF (OPAL_COMM_DEVICE_LIST,
> OpalDevicePath);
> +      if (!IsDevicePathValid(&DeviceBuffer->OpalDevicePath,
> RemainedDevicePathSize) ||
> +          (RemainedDevicePathSize != GetDevicePathSize (&DeviceBuffer-
> >OpalDevicePath))) {
> +        Status = EFI_SUCCESS;
> +        goto EXIT;
> +      }
> +
> +      if (OpalPasswordIsFullZero (DeviceBuffer->Password) ||
> +          DeviceBuffer->PasswordLength == 0 ||
> +          DeviceBuffer->PasswordLength > OPAL_PASSWORD_MAX_LENGTH) {
> +        Status = EFI_INVALID_PARAMETER;
> +        goto EXIT;
> +      }
> +
> +      Status = OpalSavePasswordToSmm (&DeviceBuffer->OpalDevicePath,
> + DeviceBuffer->Password, DeviceBuffer->PasswordLength);
>        break;
> 
>      default:
> @@ -701,6 +718,10 @@ SmmOpalPasswordHandler (
>  EXIT:
>    SmmFunctionHeader->ReturnStatus = Status;
> 
> +  if (DeviceBuffer != NULL) {
> +    FreePool (DeviceBuffer);
> +  }
> +
>    //
>    // Return EFI_SUCCESS cause only one handler can be trigged.
>    // so return EFI_WARN_INTERRUPT_SOURCE_PENDING to make all handler
> can be trigged.
> diff --git
> a/SecurityPkg/Library/OpalPasswordSupportLib/OpalPasswordSupportNotify.h
> b/SecurityPkg/Library/OpalPasswordSupportLib/OpalPasswordSupportNotify.h
> index f0ad3a1136..d543faed5d 100644
> ---
> a/SecurityPkg/Library/OpalPasswordSupportLib/OpalPasswordSupportNotify.h
> +++
> b/SecurityPkg/Library/OpalPasswordSupportLib/OpalPasswordSupportNoti
> +++ fy.h
> @@ -41,7 +41,7 @@ typedef struct {
>  } OPAL_SMM_COMMUNICATE_HEADER;
> 
>  typedef struct {
> -  UINT8                      Password[32];
> +  UINT8                      Password[OPAL_PASSWORD_MAX_LENGTH];
>    UINT8                      PasswordLength;
> 
>    EFI_DEVICE_PATH_PROTOCOL   OpalDevicePath;
> diff --git a/SecurityPkg/Tcg/Opal/OpalPasswordSmm/OpalPasswordSmm.h
> b/SecurityPkg/Tcg/Opal/OpalPasswordSmm/OpalPasswordSmm.h
> index ce88786fab..bc559f0bd1 100644
> --- a/SecurityPkg/Tcg/Opal/OpalPasswordSmm/OpalPasswordSmm.h
> +++ b/SecurityPkg/Tcg/Opal/OpalPasswordSmm/OpalPasswordSmm.h
> @@ -64,10 +64,6 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF
> ANY KIND, EITHER EXPRESS OR IMPLIED.
>  // The payload Length of HDD related ATA commands  //
>  #define HDD_PAYLOAD                      512
> -//
> -// According to ATA spec, the max Length of hdd password is 32 bytes -//
> -#define OPAL_PASSWORD_MAX_LENGTH         32
> 
>  extern VOID                              *mBuffer;
> 
> @@ -124,7 +120,7 @@ typedef struct {
> 
>    UINT32                                   NvmeNamespaceId;
> 
> -  UINT8                                    Password[32];
> +  UINT8                                    Password[OPAL_PASSWORD_MAX_LENGTH];
>    UINT8                                    PasswordLength;
> 
>    UINT32                                   Length;
> --
> 2.15.0.windows.1
> 
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