Re: [PATCH v1] MdeModulePkg/PiDxeS3BootScriptLib: Fix potential numeric truncation (CVE-2019-14563)

["Wang, Jian J" <jian.j.wang@intel.com>]

Acked-by: Jian J Wang <jian.j.wang@intel.com>

> -----Original Message-----
> From: Wu, Hao A <hao.a.wu@intel.com>
> Sent: Thursday, February 06, 2020 9:44 AM
> To: devel@edk2.groups.io
> Cc: Wu, Hao A <hao.a.wu@intel.com>; Dong, Eric <eric.dong@intel.com>;
> Wang, Jian J <jian.j.wang@intel.com>
> Subject: [PATCH v1] MdeModulePkg/PiDxeS3BootScriptLib: Fix potential numeric
> truncation (CVE-2019-14563)
> 
> REF:https://bugzilla.tianocore.org/show_bug.cgi?id=2001
> 
> For S3BootScriptLib APIs:
> 
> S3BootScriptSaveIoWrite
> S3BootScriptSaveMemWrite
> S3BootScriptSavePciCfgWrite
> S3BootScriptSavePciCfg2Write
> S3BootScriptSaveSmbusExecute
> S3BootScriptSaveInformation
> S3BootScriptSaveInformationAsciiString
> S3BootScriptLabel (happen in S3BootScriptLabelInternal())
> 
> possible numeric truncations will happen that may lead to S3 boot script
> entry with improper size being returned to store the boot script data.
> This commit will add checks to prevent this kind of issue.
> 
> Please note that the remaining S3BootScriptLib APIs:
> 
> S3BootScriptSaveIoReadWrite
> S3BootScriptSaveMemReadWrite
> S3BootScriptSavePciCfgReadWrite
> S3BootScriptSavePciCfg2ReadWrite
> S3BootScriptSaveStall
> S3BootScriptSaveDispatch2
> S3BootScriptSaveDispatch
> S3BootScriptSaveMemPoll
> S3BootScriptSaveIoPoll
> S3BootScriptSavePciPoll
> S3BootScriptSavePci2Poll
> S3BootScriptCloseTable
> S3BootScriptExecute
> S3BootScriptMoveLastOpcode
> S3BootScriptCompare
> 
> are not affected by such numeric truncation.
> 
> Cc: Eric Dong <eric.dong@intel.com>
> Cc: Jian J Wang <jian.j.wang@intel.com>
> Signed-off-by: Hao A Wu <hao.a.wu@intel.com>
> Reviewed-by: Laszlo Ersek <lersek@redhat.com>
> ---
>  MdeModulePkg/Library/PiDxeS3BootScriptLib/BootScriptSave.c | 52
> +++++++++++++++++++-
>  1 file changed, 51 insertions(+), 1 deletion(-)
> 
> diff --git a/MdeModulePkg/Library/PiDxeS3BootScriptLib/BootScriptSave.c
> b/MdeModulePkg/Library/PiDxeS3BootScriptLib/BootScriptSave.c
> index 9106e7d0f9..9315fc9f01 100644
> --- a/MdeModulePkg/Library/PiDxeS3BootScriptLib/BootScriptSave.c
> +++ b/MdeModulePkg/Library/PiDxeS3BootScriptLib/BootScriptSave.c
> @@ -1,7 +1,7 @@
>  /** @file
>    Save the S3 data to S3 boot script.
> 
> -  Copyright (c) 2006 - 2019, Intel Corporation. All rights reserved.<BR>
> +  Copyright (c) 2006 - 2020, Intel Corporation. All rights reserved.<BR>
> 
>    SPDX-License-Identifier: BSD-2-Clause-Patent
> 
> @@ -1006,6 +1006,14 @@ S3BootScriptSaveIoWrite (
>    EFI_BOOT_SCRIPT_IO_WRITE  ScriptIoWrite;
> 
>    WidthInByte = (UINT8) (0x01 << (Width & 0x03));
> +
> +  //
> +  // Truncation check
> +  //
> +  if ((Count > MAX_UINT8) ||
> +      (WidthInByte * Count > MAX_UINT8 - sizeof
> (EFI_BOOT_SCRIPT_IO_WRITE))) {
> +    return RETURN_OUT_OF_RESOURCES;
> +  }
>    Length = (UINT8)(sizeof (EFI_BOOT_SCRIPT_IO_WRITE) + (WidthInByte *
> Count));
> 
>    Script = S3BootScriptGetEntryAddAddress (Length);
> @@ -1102,6 +1110,14 @@ S3BootScriptSaveMemWrite (
>    EFI_BOOT_SCRIPT_MEM_WRITE  ScriptMemWrite;
> 
>    WidthInByte = (UINT8) (0x01 << (Width & 0x03));
> +
> +  //
> +  // Truncation check
> +  //
> +  if ((Count > MAX_UINT8) ||
> +      (WidthInByte * Count > MAX_UINT8 - sizeof
> (EFI_BOOT_SCRIPT_MEM_WRITE))) {
> +    return RETURN_OUT_OF_RESOURCES;
> +  }
>    Length = (UINT8)(sizeof (EFI_BOOT_SCRIPT_MEM_WRITE) + (WidthInByte *
> Count));
> 
>    Script = S3BootScriptGetEntryAddAddress (Length);
> @@ -1206,6 +1222,14 @@ S3BootScriptSavePciCfgWrite (
>    }
> 
>    WidthInByte = (UINT8) (0x01 << (Width & 0x03));
> +
> +  //
> +  // Truncation check
> +  //
> +  if ((Count > MAX_UINT8) ||
> +      (WidthInByte * Count > MAX_UINT8 - sizeof
> (EFI_BOOT_SCRIPT_PCI_CONFIG_WRITE))) {
> +    return RETURN_OUT_OF_RESOURCES;
> +  }
>    Length = (UINT8)(sizeof (EFI_BOOT_SCRIPT_PCI_CONFIG_WRITE) +
> (WidthInByte * Count));
> 
>    Script = S3BootScriptGetEntryAddAddress (Length);
> @@ -1324,6 +1348,14 @@ S3BootScriptSavePciCfg2Write (
>    }
> 
>    WidthInByte = (UINT8) (0x01 << (Width & 0x03));
> +
> +  //
> +  // Truncation check
> +  //
> +  if ((Count > MAX_UINT8) ||
> +      (WidthInByte * Count > MAX_UINT8 - sizeof
> (EFI_BOOT_SCRIPT_PCI_CONFIG2_WRITE))) {
> +    return RETURN_OUT_OF_RESOURCES;
> +  }
>    Length = (UINT8)(sizeof (EFI_BOOT_SCRIPT_PCI_CONFIG2_WRITE) +
> (WidthInByte * Count));
> 
>    Script = S3BootScriptGetEntryAddAddress (Length);
> @@ -1549,6 +1581,12 @@ S3BootScriptSaveSmbusExecute (
>      return Status;
>    }
> 
> +  //
> +  // Truncation check
> +  //
> +  if (BufferLength > MAX_UINT8 - sizeof (EFI_BOOT_SCRIPT_SMBUS_EXECUTE))
> {
> +    return RETURN_OUT_OF_RESOURCES;
> +  }
>    DataSize = (UINT8)(sizeof (EFI_BOOT_SCRIPT_SMBUS_EXECUTE) +
> BufferLength);
> 
>    Script = S3BootScriptGetEntryAddAddress (DataSize);
> @@ -1736,6 +1774,12 @@ S3BootScriptSaveInformation (
>    UINT8                 *Script;
>    EFI_BOOT_SCRIPT_INFORMATION  ScriptInformation;
> 
> +  //
> +  // Truncation check
> +  //
> +  if (InformationLength > MAX_UINT8 - sizeof
> (EFI_BOOT_SCRIPT_INFORMATION)) {
> +    return RETURN_OUT_OF_RESOURCES;
> +  }
>    Length = (UINT8)(sizeof (EFI_BOOT_SCRIPT_INFORMATION) +
> InformationLength);
> 
>    Script = S3BootScriptGetEntryAddAddress (Length);
> @@ -2195,6 +2239,12 @@ S3BootScriptLabelInternal (
>    UINT8                 *Script;
>    EFI_BOOT_SCRIPT_INFORMATION  ScriptInformation;
> 
> +  //
> +  // Truncation check
> +  //
> +  if (InformationLength > MAX_UINT8 - sizeof
> (EFI_BOOT_SCRIPT_INFORMATION)) {
> +    return RETURN_OUT_OF_RESOURCES;
> +  }
>    Length = (UINT8)(sizeof (EFI_BOOT_SCRIPT_INFORMATION) +
> InformationLength);
> 
>    Script = S3BootScriptGetEntryAddAddress (Length);
> --
> 2.12.0.windows.1