Re: [edk2-devel] [PATCH v1 1/1] ShellPkg: acpiview: Prevent infinite loop if structure length is 0

["Krzysztof Koch" <krzysztof.koch@arm.com>]

Hi Liming,

I haven't created a BZ yet, shall I create one? It would be great if the patch makes it to the stable tag.

Over the last few months I added some security features to acpiview. They make this debug tool less sensitive to exploits from ACPI tables. This patch completes my efforts in making the tool more reliable.

Kind regards,
Krzysztof

-----Original Message-----
From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Liming Gao via Groups.Io
Sent: Monday, February 17, 2020 15:11
To: devel@edk2.groups.io; Krzysztof Koch <Krzysztof.Koch@arm.com>
Cc: Ni, Ray <ray.ni@intel.com>; Gao, Zhichao <zhichao.gao@intel.com>; Sami Mujawar <Sami.Mujawar@arm.com>; Matteo Carlini <Matteo.Carlini@arm.com>; nd <nd@arm.com>
Subject: Re: [edk2-devel] [PATCH v1 1/1] ShellPkg: acpiview: Prevent infinite loop if structure length is 0

Krzysztof:
  Is there one BZ for this issue? Does this patch catch to this edk2 stable tag 202002?

Thanks
Liming
> -----Original Message-----
> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of 
> Krzysztof Koch
> Sent: Friday, February 14, 2020 9:59 PM
> To: devel@edk2.groups.io
> Cc: Ni, Ray <ray.ni@intel.com>; Gao, Zhichao <zhichao.gao@intel.com>; 
> Sami.Mujawar@arm.com; Matteo.Carlini@arm.com; nd@arm.com
> Subject: [edk2-devel] [PATCH v1 1/1] ShellPkg: acpiview: Prevent 
> infinite loop if structure length is 0
> 
> Extend validation of ACPI structure lengths which are read from the 
> ACPI table being parsed. Additionally check if the structure 'Length'
> field value is positive. If not, stop parsing the faulting table.
> 
> Some ACPI tables define internal structures of variable size. The 
> 'Length' field inside the substructure is used to update a pointer 
> used for table traversal. If the byte-length of the structure is equal 
> to 0, acpiview can enter an infinite loop. This condition can occur 
> if, for example, the zero-allocated ACPI table buffer is not fully populated.
> This is typically a bug on the ACPI table writer side.
> 
> In short, this method helps acpiview recover gracefully from a 
> zero-valued ACPI structure length.
> 
> Signed-off-by: Krzysztof Koch <krzysztof.koch@arm.com>
> ---
> 
> Changes can be seen at: 
> https://github.com/KrzysztofKoch1/edk2/tree/612_acpiview_prevent_inf_l
> oops_v1
> 
> Notes:
>     v1:
>     - prevent infinite loops in acpiview parsers [Krzysztof]
> 
>
> ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Dbg2/Dbg2Parser.c 
> | 15 ++++++-----
> ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Gtdt/GtdtParser.c 
> | 13 ++++-----
> ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Iort/IortParser.c 
> | 14 +++++-----
> ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Madt/MadtParser.c 
> | 28 ++++++--------------
> ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Pptt/PpttParser.c 
> | 15 ++++++-----
> ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Srat/SratParser.c 
> | 14 +++++-----
>  6 files changed, 47 insertions(+), 52 deletions(-)
> 
> diff --git 
> a/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Dbg2/Dbg2Parser
> .c 
> b/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Dbg2/Dbg2Parser
> .c index 
> 0f730a306a94329a23fbaf54b59f1833b44616ba..9df111ecaa7d7a703a13a39c243e
> d78b9f12ee97 100644
> --- 
> a/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Dbg2/Dbg2Parser
> .c
> +++ b/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Dbg2/Dbg2Pa
> +++ rser.c
> @@ -1,7 +1,7 @@
>  /** @file
>    DBG2 table parser
> 
> -  Copyright (c) 2016 - 2019, ARM Limited. All rights reserved.
> +  Copyright (c) 2016 - 2020, ARM Limited. All rights reserved.
>    SPDX-License-Identifier: BSD-2-Clause-Patent
> 
>    @par Reference(s):
> @@ -282,15 +282,16 @@ ParseAcpiDbg2 (
>        return;
>      }
> 
> -    // Make sure the Debug Device Information structure lies inside the table.
> -    if ((Offset + *DbgDevInfoLen) > AcpiTableLength) {
> +    // Validate Debug Device Information Structure length
> +    if ((*DbgDevInfoLen == 0) ||
> +        ((Offset + (*DbgDevInfoLen)) > AcpiTableLength)) {
>        IncrementErrorCount ();
>        Print (
> -        L"ERROR: Invalid Debug Device Information structure length. " \
> -          L"DbgDevInfoLen = %d. RemainingTableBufferLength = %d. " \
> -          L"DBG2 parsing aborted.\n",
> +        L"ERROR: Invalid Debug Device Information Structure length. " \
> +          L"Length = %d. Offset = %d. AcpiTableLength = %d.\n",
>          *DbgDevInfoLen,
> -        AcpiTableLength - Offset
> +        Offset,
> +        AcpiTableLength
>          );
>        return;
>      }
> diff --git 
> a/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Gtdt/GtdtParser
> .c 
> b/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Gtdt/GtdtParser
> .c index 
> 699a55b549ec3fa61bbd156898821055dc019199..bdd30ff45c61142c071ead63a27b
> abab8998721b 100644
> --- 
> a/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Gtdt/GtdtParser
> .c
> +++ b/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Gtdt/GtdtPa
> +++ rser.c
> @@ -1,7 +1,7 @@
>  /** @file
>    GTDT table parser
> 
> -  Copyright (c) 2016 - 2019, ARM Limited. All rights reserved.
> +  Copyright (c) 2016 - 2020, ARM Limited. All rights reserved.
>    SPDX-License-Identifier: BSD-2-Clause-Patent
> 
>    @par Reference(s):
> @@ -327,15 +327,16 @@ ParseAcpiGtdt (
>        return;
>      }
> 
> -    // Make sure the Platform Timer is inside the table.
> -    if ((Offset + *PlatformTimerLength) > AcpiTableLength) {
> +    // Validate Platform Timer Structure length
> +    if ((*PlatformTimerLength == 0) ||
> +        ((Offset + (*PlatformTimerLength)) > AcpiTableLength)) {
>        IncrementErrorCount ();
>        Print (
>          L"ERROR: Invalid Platform Timer Structure length. " \
> -          L"PlatformTimerLength = %d. RemainingTableBufferLength = %d. " \
> -          L"GTDT parsing aborted.\n",
> +          L"Length = %d. Offset = %d. AcpiTableLength = %d.\n",
>          *PlatformTimerLength,
> -        AcpiTableLength - Offset
> +        Offset,
> +        AcpiTableLength
>          );
>        return;
>      }
> diff --git 
> a/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Iort/IortParser
> .c 
> b/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Iort/IortParser
> .c index 
> 9d5d937c7b2c19945ca2ad3eba644bdfc09cc3f6..9a006a01448b897865cd7cd85651
> c816933acf05 100644
> --- 
> a/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Iort/IortParser
> .c
> +++ b/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Iort/IortPa
> +++ rser.c
> @@ -1,7 +1,7 @@
>  /** @file
>    IORT table parser
> 
> -  Copyright (c) 2016 - 2019, ARM Limited. All rights reserved.
> +  Copyright (c) 2016 - 2020, ARM Limited. All rights reserved.
>    SPDX-License-Identifier: BSD-2-Clause-Patent
> 
>    @par Reference(s):
> @@ -687,14 +687,16 @@ ParseAcpiIort (
>        return;
>      }
> 
> -    // Make sure the IORT Node is inside the table
> -    if ((Offset + (*IortNodeLength)) > AcpiTableLength) {
> +    // Validate IORT Node length
> +    if ((*IortNodeLength == 0) ||
> +        ((Offset + (*IortNodeLength)) > AcpiTableLength)) {
>        IncrementErrorCount ();
>        Print (
> -        L"ERROR: Invalid IORT node length. IortNodeLength = %d. " \
> -          L"RemainingTableBufferLength = %d. IORT parsing aborted.\n",
> +        L"ERROR: Invalid IORT Node length. " \
> +          L"Length = %d. Offset = %d. AcpiTableLength = %d.\n",
>          *IortNodeLength,
> -        AcpiTableLength - Offset
> +        Offset,
> +        AcpiTableLength
>          );
>        return;
>      }
> diff --git 
> a/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Madt/MadtParser
> .c 
> b/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Madt/MadtParser
> .c index 
> 438905cb24f58b8b82e8fe61280e72f765d578d8..f85d2b36532cfc5db36fe7bef983
> 0cccc64969cc 100644
> --- 
> a/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Madt/MadtParser
> .c
> +++ b/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Madt/MadtPa
> +++ rser.c
> @@ -1,7 +1,7 @@
>  /** @file
>    MADT table parser
> 
> -  Copyright (c) 2016 - 2019, ARM Limited. All rights reserved.
> +  Copyright (c) 2016 - 2020, ARM Limited. All rights reserved.
>    SPDX-License-Identifier: BSD-2-Clause-Patent
> 
>    @par Reference(s):
> @@ -273,28 +273,16 @@ ParseAcpiMadt (
>        return;
>      }
> 
> -    // Make sure forward progress is made.
> -    if (*MadtInterruptControllerLength < 2) {
> +    // Validate Interrupt Controller Structure length
> +    if ((*MadtInterruptControllerLength == 0) ||
> +        ((Offset + (*MadtInterruptControllerLength)) > 
> + AcpiTableLength)) {
>        IncrementErrorCount ();
>        Print (
> -        L"ERROR: Structure length is too small: " \
> -          L"MadtInterruptControllerLength = %d. " \
> -          L"MadtInterruptControllerType = %d. MADT parsing aborted.\n",
> +        L"ERROR: Invalid Interrupt Controller Structure length. " \
> +          L"Length = %d. Offset = %d. AcpiTableLength = %d.\n",
>          *MadtInterruptControllerLength,
> -        *MadtInterruptControllerType
> -        );
> -      return;
> -    }
> -
> -    // Make sure the MADT structure lies inside the table
> -    if ((Offset + *MadtInterruptControllerLength) > AcpiTableLength) {
> -      IncrementErrorCount ();
> -      Print (
> -        L"ERROR: Invalid MADT structure length. " \
> -          L"MadtInterruptControllerLength = %d. " \
> -          L"RemainingTableBufferLength = %d. MADT parsing aborted.\n",
> -        *MadtInterruptControllerLength,
> -        AcpiTableLength - Offset
> +        Offset,
> +        AcpiTableLength
>          );
>        return;
>      }
> diff --git 
> a/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Pptt/PpttParser
> .c 
> b/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Pptt/PpttParser
> .c index 
> 675ba75f02b367cd5ad9f2ac23c30ed0ab58f286..0db272c16af0ad8824c8da4c88dd
> 409c8550112a 100644
> --- 
> a/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Pptt/PpttParser
> .c
> +++ b/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Pptt/PpttPa
> +++ rser.c
> @@ -1,7 +1,7 @@
>  /** @file
>    PPTT table parser
> 
> -  Copyright (c) 2019, ARM Limited. All rights reserved.
> +  Copyright (c) 2019 - 2020, ARM Limited. All rights reserved.
>    SPDX-License-Identifier: BSD-2-Clause-Patent
> 
>    @par Reference(s):
> @@ -425,15 +425,16 @@ ParseAcpiPptt (
>        return;
>      }
> 
> -    // Make sure the PPTT structure lies inside the table
> -    if ((Offset + *ProcessorTopologyStructureLength) > AcpiTableLength) {
> +    // Validate Processor Topology Structure length
> +    if ((*ProcessorTopologyStructureLength == 0) ||
> +        ((Offset + (*ProcessorTopologyStructureLength)) > 
> + AcpiTableLength)) {
>        IncrementErrorCount ();
>        Print (
> -        L"ERROR: Invalid PPTT structure length. " \
> -          L"ProcessorTopologyStructureLength = %d. " \
> -          L"RemainingTableBufferLength = %d. PPTT parsing aborted.\n",
> +        L"ERROR: Invalid Processor Topology Structure length. " \
> +          L"Length = %d. Offset = %d. AcpiTableLength = %d.\n",
>          *ProcessorTopologyStructureLength,
> -        AcpiTableLength - Offset
> +        Offset,
> +        AcpiTableLength
>          );
>        return;
>      }
> diff --git 
> a/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Srat/SratParser
> .c 
> b/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Srat/SratParser
> .c index 
> 3613900ae322483fdd3d3383de4e22ba75b2128b..6f66be68cc0bed14811a0432c61a
> 79fd47c54890 100644
> --- 
> a/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Srat/SratParser
> .c
> +++ b/ShellPkg/Library/UefiShellAcpiViewCommandLib/Parsers/Srat/SratPa
> +++ rser.c
> @@ -1,7 +1,7 @@
>  /** @file
>    SRAT table parser
> 
> -  Copyright (c) 2016 - 2019, ARM Limited. All rights reserved.
> +  Copyright (c) 2016 - 2020, ARM Limited. All rights reserved.
>    SPDX-License-Identifier: BSD-2-Clause-Patent
> 
>    @par Reference(s):
> @@ -412,14 +412,16 @@ ParseAcpiSrat (
>        return;
>      }
> 
> -    // Make sure the SRAT structure lies inside the table
> -    if ((Offset + *SratRALength) > AcpiTableLength) {
> +    // Validate Static Resource Allocation Structure length
> +    if ((*SratRALength == 0) ||
> +        ((Offset + (*SratRALength)) > AcpiTableLength)) {
>        IncrementErrorCount ();
>        Print (
> -        L"ERROR: Invalid SRAT structure length. SratRALength = %d. " \
> -          L"RemainingTableBufferLength = %d. SRAT parsing aborted.\n",
> +        L"ERROR: Invalid Static Resource Allocation Structure length. " \
> +          L"Length = %d. Offset = %d. AcpiTableLength = %d.\n",
>          *SratRALength,
> -        AcpiTableLength - Offset
> +        Offset,
> +        AcpiTableLength
>          );
>        return;
>      }
> --
> 'Guid(CE165669-3EF3-493F-B85D-6190EE5B9759)'
> 
> 
>