Re: [edk2-devel] [PATCH V2 4/9] MdeModulePkg/Variable: Add local auth status in VariableParsing

["Kubacki, Michael A" <michael.a.kubacki@intel.com>]

The InitVariableParsing () function has already been removed entirely in V3+ to
prevent issues like this. I strongly believe this is the right direction. It is only a
matter of time before someone else modifies the global and forgets to call
InitVariableParsing ().

Furthermore, VariablePei has already added a parameter to most of the equivalent
functions implemented in that driver so there's some potential to further
consolidate the variable parsing implementation in the future.

Thanks,
Michael

> -----Original Message-----
> From: Wu, Hao A <hao.a.wu@intel.com>
> Sent: Wednesday, October 16, 2019 12:55 AM
> To: Kubacki, Michael A <michael.a.kubacki@intel.com>;
> devel@edk2.groups.io
> Cc: Bi, Dandan <dandan.bi@intel.com>; Ard Biesheuvel
> <ard.biesheuvel@linaro.org>; Dong, Eric <eric.dong@intel.com>; Laszlo Ersek
> <lersek@redhat.com>; Gao, Liming <liming.gao@intel.com>; Kinney, Michael
> D <michael.d.kinney@intel.com>; Ni, Ray <ray.ni@intel.com>; Wang, Jian J
> <jian.j.wang@intel.com>; Yao, Jiewen <jiewen.yao@intel.com>
> Subject: RE: [edk2-devel] [PATCH V2 4/9] MdeModulePkg/Variable: Add local
> auth status in VariableParsing
> 
> > -----Original Message-----
> > From: Kubacki, Michael A
> > Sent: Friday, October 04, 2019 2:35 AM
> > To: Wu, Hao A; devel@edk2.groups.io
> > Cc: Bi, Dandan; Ard Biesheuvel; Dong, Eric; Laszlo Ersek; Gao, Liming;
> > Kinney, Michael D; Ni, Ray; Wang, Jian J; Yao, Jiewen
> > Subject: RE: [edk2-devel] [PATCH V2 4/9] MdeModulePkg/Variable: Add
> > local auth status in VariableParsing
> >
> > I will make the following changes in V3:
> >
> > > InitVariableParsing() seems an internal function, the 'EFIAPI'
> > > keyword can
> > be
> > > dropped. Please help to update the function definition in .C file as well.
> >
> > I will remove the EFIAPI keyword.
> >
> > > > diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
> > > > b/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
> > > > index 1a57d7e1ba..53d797152c 100644
> > > > --- a/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
> > > > +++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
> > > > @@ -3326,6 +3326,9 @@ InitNonVolatileVariableStore (
> > > >    mVariableModuleGlobal->MaxVariableSize = PcdGet32
> > > > (PcdMaxVariableSize);
> > > >    mVariableModuleGlobal->MaxAuthVariableSize = ((PcdGet32
> > > > (PcdMaxAuthVariableSize) != 0) ? PcdGet32 (PcdMaxAuthVariableSize)
> :
> > > > mVariableModuleGlobal->MaxVariableSize);
> > > >
> > > > +  Status = InitVariableParsing (mVariableModuleGlobal-
> > > > >VariableGlobal.AuthFormat);
> > > > +  ASSERT_EFI_ERROR (Status);
> > > > +
> > >
> > >
> > > After the above initialization, mVariableModuleGlobal-
> > > >VariableGlobal.AuthFormat
> > > will be changed temporarily within
> > > ConvertNormalVarStorageToAuthVarStorage() if normal HOB variable
> > > store will be converted to the auth format:
> > >
> > > VOID *
> > > ConvertNormalVarStorageToAuthVarStorage (
> > >   VARIABLE_STORE_HEADER *NormalVarStorage
> > >   )
> > > {
> > >   ...
> > >   //
> > >   // Set AuthFormat as FALSE for normal variable storage
> > >   //
> > >   mVariableModuleGlobal->VariableGlobal.AuthFormat = FALSE;
> > >   ...
> > >   //
> > >   // Restore AuthFormat
> > >   //
> > >   mVariableModuleGlobal->VariableGlobal.AuthFormat = TRUE;
> > >   return AuthVarStorage;
> > > }
> > >
> > >
> > > I think there will be issues in such converting, since I found that
> > > at least
> > > GetVariableHeaderSize() and NameSizeOfVariable() get called during
> > > the execution of ConvertNormalVarStorageToAuthVarStorage(). And
> they
> > > are checking 'mAuthFormat' rather than 'mVariableModuleGlobal-
> > > >VariableGlobal.AuthFormat'.
> > >
> > >
> >
> > You're right that will be a problem. I missed this temporary change in
> > the value.
> > I'm going to have all the functions dependent on authentication status
> > in VariableParsing.c take it as a parameter and let the respective
> > drivers linked against it maintain their own single copy of the authentication
> state.
> 
> 
> I am really sorry for not raising this question until I saw the latest patch
> series:
> 
> Is it possible to call the InitVariableParsing() function (maybe a rename for
> the function for better understanding) for the temporary changes for
> 'mVariableModuleGlobal->VariableGlobal.AuthFormat' in function
> ConvertNormalVarStorageToAuthVarStorage()?
> 
> In my opinion, doing so can avoid changing many function interfaces.
> 
> Best Regards,
> Hao Wu
> 
> 
> >
> > > >    //
> > > >    // Parse non-volatile variable data and get last variable offset.
> > > >    //
> > > > @@ -3756,18 +3759,13 @@ VariableCommonInitialize (
> > > >
> > > >    //
> > > >    // mVariableModuleGlobal->VariableGlobal.AuthFormat
> > > > -  // has been initialized in InitNonVolatileVariableStore().
> > > > +  // is initialized in InitNonVolatileVariableStore().
> > > >    //
> > > >    if (mVariableModuleGlobal->VariableGlobal.AuthFormat) {
> > > >      DEBUG ((EFI_D_INFO, "Variable driver will work with auth
> > > > variable format!\n"));
> > > > -    //
> > > > -    // Set AuthSupport to FALSE first, VariableWriteServiceInitialize() will
> > > > initialize it.
> > > > -    //
> > > > -    mVariableModuleGlobal->VariableGlobal.AuthSupport = FALSE;
> > > >      VariableGuid = &gEfiAuthenticatedVariableGuid;
> > > >    } else {
> > > >      DEBUG ((EFI_D_INFO, "Variable driver will work without auth
> > > > variable support!\n"));
> > > > -    mVariableModuleGlobal->VariableGlobal.AuthSupport = FALSE;
> > >
> > >
> > > Not sure why the above changes belong to this patch.
> > > Could you help to double confirm?
> >
> > This was used during testing and is not needed. I will remove it.
> >
> > Thanks,
> > Michael
> >
> > > -----Original Message-----
> > > From: Wu, Hao A <hao.a.wu@intel.com>
> > > Sent: Thursday, October 3, 2019 1:04 AM
> > > To: devel@edk2.groups.io; Kubacki, Michael A
> > > <michael.a.kubacki@intel.com>
> > > Cc: Bi, Dandan <dandan.bi@intel.com>; Ard Biesheuvel
> > > <ard.biesheuvel@linaro.org>; Dong, Eric <eric.dong@intel.com>;
> > > Laszlo
> > Ersek
> > > <lersek@redhat.com>; Gao, Liming <liming.gao@intel.com>; Kinney,
> > Michael
> > > D <michael.d.kinney@intel.com>; Ni, Ray <ray.ni@intel.com>; Wang,
> > > Jian J <jian.j.wang@intel.com>; Yao, Jiewen <jiewen.yao@intel.com>
> > > Subject: RE: [edk2-devel] [PATCH V2 4/9] MdeModulePkg/Variable: Add
> > local
> > > auth status in VariableParsing
> > >
> > > Inline comments below:
> > >
> > >
> > > > -----Original Message-----
> > > > From: devel@edk2.groups.io [mailto:devel@edk2.groups.io] On Behalf
> > Of
> > > > Kubacki, Michael A
> > > > Sent: Saturday, September 28, 2019 9:47 AM
> > > > To: devel@edk2.groups.io
> > > > Cc: Bi, Dandan; Ard Biesheuvel; Dong, Eric; Laszlo Ersek; Gao,
> > > > Liming; Kinney, Michael D; Ni, Ray; Wang, Jian J; Wu, Hao A; Yao,
> > > > Jiewen
> > > > Subject: [edk2-devel] [PATCH V2 4/9] MdeModulePkg/Variable: Add
> > > > local auth status in VariableParsing
> > > >
> > > > The file VariableParsing.c provides generic functionality related
> > > > to parsing variable related structures and information. In order
> > > > to calculate offsets for certain operations, the functions must
> > > > know if authenticated variables are enabled as this increases the
> > > > size of variable headers.
> > > >
> > > > This change removes linking against a global variable in an
> > > > external file in favor of a statically scoped variable in
> > > > VariableParsing.c Because this file is unaware of how the
> > > > authenticated variable status is determined, the variable is set
> > > > through a function interface invoked during variable driver initialization.
> > > >
> > > > Cc: Dandan Bi <dandan.bi@intel.com>
> > > > Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> > > > Cc: Eric Dong <eric.dong@intel.com>
> > > > Cc: Laszlo Ersek <lersek@redhat.com>
> > > > Cc: Liming Gao <liming.gao@intel.com>
> > > > Cc: Michael D Kinney <michael.d.kinney@intel.com>
> > > > Cc: Ray Ni <ray.ni@intel.com>
> > > > Cc: Jian J Wang <jian.j.wang@intel.com>
> > > > Cc: Hao A Wu <hao.a.wu@intel.com>
> > > > Cc: Jiewen Yao <jiewen.yao@intel.com>
> > > > Signed-off-by: Michael Kubacki <michael.a.kubacki@intel.com>
> > > > ---
> > > >  MdeModulePkg/Universal/Variable/RuntimeDxe/VariableParsing.h |
> 14
> > > > +++++++++
> > > >  MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c        | 10
> > +++---
> > > >  MdeModulePkg/Universal/Variable/RuntimeDxe/VariableParsing.c |
> 33
> > > > ++++++++++++++++----
> > > >  3 files changed, 45 insertions(+), 12 deletions(-)
> > > >
> > > > diff --git
> > > > a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableParsing.h
> > > > b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableParsing.h
> > > > index 6f2000f3ee..3eba590634 100644
> > > > ---
> a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableParsing.h
> > > > +++
> > b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableParsing.h
> > > > @@ -308,4 +308,18 @@ UpdateVariableInfo (
> > > >    IN OUT VARIABLE_INFO_ENTRY  **VariableInfo
> > > >    );
> > > >
> > > > +/**
> > > > +  Initializes context needed for variable parsing functions.
> > > > +
> > > > +  @param[in]       AuthFormat          If true then indicates authenticated
> > > > variables are supported
> > > > +
> > > > +  @retval          EFI_SUCCESS         Initialized successfully
> > > > +  @retval          Others              An error occurred during initialization
> > > > +**/
> > > > +EFI_STATUS
> > > > +EFIAPI
> > > > +InitVariableParsing (
> > >
> > >
> > > InitVariableParsing() seems an internal function, the 'EFIAPI'
> > > keyword can
> > be
> > > dropped. Please help to update the function definition in .C file as well.
> > >
> > >
> > > > +  IN  BOOLEAN   AuthFormat
> > > > +  );
> > > > +
> > > >  #endif
> > > > diff --git a/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
> > > > b/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
> > > > index 1a57d7e1ba..53d797152c 100644
> > > > --- a/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
> > > > +++ b/MdeModulePkg/Universal/Variable/RuntimeDxe/Variable.c
> > > > @@ -3326,6 +3326,9 @@ InitNonVolatileVariableStore (
> > > >    mVariableModuleGlobal->MaxVariableSize = PcdGet32
> > > > (PcdMaxVariableSize);
> > > >    mVariableModuleGlobal->MaxAuthVariableSize = ((PcdGet32
> > > > (PcdMaxAuthVariableSize) != 0) ? PcdGet32 (PcdMaxAuthVariableSize)
> :
> > > > mVariableModuleGlobal->MaxVariableSize);
> > > >
> > > > +  Status = InitVariableParsing (mVariableModuleGlobal-
> > > > >VariableGlobal.AuthFormat);
> > > > +  ASSERT_EFI_ERROR (Status);
> > > > +
> > >
> > >
> > > After the above initialization, mVariableModuleGlobal-
> > > >VariableGlobal.AuthFormat
> > > will be changed temporarily within
> > > ConvertNormalVarStorageToAuthVarStorage() if normal HOB variable
> > > store will be converted to the auth format:
> > >
> > > VOID *
> > > ConvertNormalVarStorageToAuthVarStorage (
> > >   VARIABLE_STORE_HEADER *NormalVarStorage
> > >   )
> > > {
> > >   ...
> > >   //
> > >   // Set AuthFormat as FALSE for normal variable storage
> > >   //
> > >   mVariableModuleGlobal->VariableGlobal.AuthFormat = FALSE;
> > >   ...
> > >   //
> > >   // Restore AuthFormat
> > >   //
> > >   mVariableModuleGlobal->VariableGlobal.AuthFormat = TRUE;
> > >   return AuthVarStorage;
> > > }
> > >
> > >
> > > I think there will be issues in such converting, since I found that
> > > at least
> > > GetVariableHeaderSize() and NameSizeOfVariable() get called during
> > > the execution of ConvertNormalVarStorageToAuthVarStorage(). And
> they
> > > are checking 'mAuthFormat' rather than 'mVariableModuleGlobal-
> > > >VariableGlobal.AuthFormat'.
> > >
> > >
> > > >    //
> > > >    // Parse non-volatile variable data and get last variable offset.
> > > >    //
> > > > @@ -3756,18 +3759,13 @@ VariableCommonInitialize (
> > > >
> > > >    //
> > > >    // mVariableModuleGlobal->VariableGlobal.AuthFormat
> > > > -  // has been initialized in InitNonVolatileVariableStore().
> > > > +  // is initialized in InitNonVolatileVariableStore().
> > > >    //
> > > >    if (mVariableModuleGlobal->VariableGlobal.AuthFormat) {
> > > >      DEBUG ((EFI_D_INFO, "Variable driver will work with auth
> > > > variable format!\n"));
> > > > -    //
> > > > -    // Set AuthSupport to FALSE first, VariableWriteServiceInitialize() will
> > > > initialize it.
> > > > -    //
> > > > -    mVariableModuleGlobal->VariableGlobal.AuthSupport = FALSE;
> > > >      VariableGuid = &gEfiAuthenticatedVariableGuid;
> > > >    } else {
> > > >      DEBUG ((EFI_D_INFO, "Variable driver will work without auth
> > > > variable support!\n"));
> > > > -    mVariableModuleGlobal->VariableGlobal.AuthSupport = FALSE;
> > >
> > >
> > > Not sure why the above changes belong to this patch.
> > > Could you help to double confirm?
> > >
> > > Best Regards,
> > > Hao Wu
> > >
> > >
> > > >      VariableGuid = &gEfiVariableGuid;
> > > >    }
> > > >
> > > > diff --git
> > > > a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableParsing.c
> > > > b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableParsing.c
> > > > index 394195342d..0a47f6d10d 100644
> > > > ---
> a/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableParsing.c
> > > > +++
> > b/MdeModulePkg/Universal/Variable/RuntimeDxe/VariableParsing.c
> > > > @@ -9,6 +9,8 @@ SPDX-License-Identifier: BSD-2-Clause-Patent
> > > >
> > > >  #include "VariableParsing.h"
> > > >
> > > > +STATIC  BOOLEAN   mAuthFormat;
> > > > +
> > > >  /**
> > > >
> > > >    This code checks if variable header is valid or not.
> > > > @@ -88,7 +90,7 @@ GetVariableHeaderSize (  {
> > > >    UINTN Value;
> > > >
> > > > -  if (mVariableModuleGlobal->VariableGlobal.AuthFormat) {
> > > > +  if (mAuthFormat) {
> > > >      Value = sizeof (AUTHENTICATED_VARIABLE_HEADER);
> > > >    } else {
> > > >      Value = sizeof (VARIABLE_HEADER); @@ -114,7 +116,7 @@
> > > > NameSizeOfVariable (
> > > >    AUTHENTICATED_VARIABLE_HEADER *AuthVariable;
> > > >
> > > >    AuthVariable = (AUTHENTICATED_VARIABLE_HEADER *) Variable;
> > > > -  if (mVariableModuleGlobal->VariableGlobal.AuthFormat) {
> > > > +  if (mAuthFormat) {
> > > >      if (AuthVariable->State == (UINT8) (-1) ||
> > > >         AuthVariable->DataSize == (UINT32) (-1) ||
> > > >         AuthVariable->NameSize == (UINT32) (-1) || @@ -149,7
> > > > +151,7 @@ SetNameSizeOfVariable (
> > > >    AUTHENTICATED_VARIABLE_HEADER *AuthVariable;
> > > >
> > > >    AuthVariable = (AUTHENTICATED_VARIABLE_HEADER *) Variable;
> > > > -  if (mVariableModuleGlobal->VariableGlobal.AuthFormat) {
> > > > +  if (mAuthFormat) {
> > > >      AuthVariable->NameSize = (UINT32) NameSize;
> > > >    } else {
> > > >      Variable->NameSize = (UINT32) NameSize; @@ -173,7 +175,7 @@
> > > > DataSizeOfVariable (
> > > >    AUTHENTICATED_VARIABLE_HEADER *AuthVariable;
> > > >
> > > >    AuthVariable = (AUTHENTICATED_VARIABLE_HEADER *) Variable;
> > > > -  if (mVariableModuleGlobal->VariableGlobal.AuthFormat) {
> > > > +  if (mAuthFormat) {
> > > >      if (AuthVariable->State == (UINT8) (-1) ||
> > > >         AuthVariable->DataSize == (UINT32) (-1) ||
> > > >         AuthVariable->NameSize == (UINT32) (-1) || @@ -208,7
> > > > +210,7 @@ SetDataSizeOfVariable (
> > > >    AUTHENTICATED_VARIABLE_HEADER *AuthVariable;
> > > >
> > > >    AuthVariable = (AUTHENTICATED_VARIABLE_HEADER *) Variable;
> > > > -  if (mVariableModuleGlobal->VariableGlobal.AuthFormat) {
> > > > +  if (mAuthFormat) {
> > > >      AuthVariable->DataSize = (UINT32) DataSize;
> > > >    } else {
> > > >      Variable->DataSize = (UINT32) DataSize; @@ -248,7 +250,7 @@
> > > > GetVendorGuidPtr (
> > > >    AUTHENTICATED_VARIABLE_HEADER *AuthVariable;
> > > >
> > > >    AuthVariable = (AUTHENTICATED_VARIABLE_HEADER *) Variable;
> > > > -  if (mVariableModuleGlobal->VariableGlobal.AuthFormat) {
> > > > +  if (mAuthFormat) {
> > > >      return &AuthVariable->VendorGuid;
> > > >    } else {
> > > >      return &Variable->VendorGuid; @@ -746,3 +748,22 @@
> > > > UpdateVariableInfo (
> > > >      }
> > > >    }
> > > >  }
> > > > +
> > > > +/**
> > > > +  Initializes context needed for variable parsing functions.
> > > > +
> > > > +  @param[in]       AuthFormat          If true then indicates authenticated
> > > > variables are supported
> > > > +
> > > > +  @retval          EFI_SUCCESS         Initialized successfully
> > > > +  @retval          Others              An error occurred during initialization
> > > > +**/
> > > > +EFI_STATUS
> > > > +EFIAPI
> > > > +InitVariableParsing (
> > > > +  IN  BOOLEAN   AuthFormat
> > > > +  )
> > > > +{
> > > > +  mAuthFormat = AuthFormat;
> > > > +
> > > > +  return EFI_SUCCESS;
> > > > +}
> > > > --
> > > > 2.16.2.windows.1
> > > >
> > > >
> > > > 
> > >
> >
>