SecurityPkg: VariableServiceSetVariable(): fix dbt <-> GUID association

SVN r16380 ("UEFI 2.4 X509 Certificate Hash and RFC3161 Timestamp
Verification support for Secure Boot") broke the "dbt" variable's
association with its expected namespace GUID.

According to "MdePkg/Include/Guid/ImageAuthentication.h", *all* of the
"db", "dbx", and "dbt" (== EFI_IMAGE_SECURITY_DATABASE2) variables have
their special meanings in the EFI_IMAGE_SECURITY_DATABASE_GUID namespace.

However, the above commit introduced the following expression in
VariableServiceSetVariable():

> -  } else if (CompareGuid (VendorGuid, &gEfiImageSecurityDatabaseGuid) &&
> -          ((StrCmp (VariableName, EFI_IMAGE_SECURITY_DATABASE) == 0) || (StrCmp (VariableName, EFI_IMAGE_SECURITY_DATABASE1) == 0))) {
> +  } else if (CompareGuid (VendorGuid, &gEfiImageSecurityDatabaseGuid) &&
> +          ((StrCmp (VariableName, EFI_IMAGE_SECURITY_DATABASE) == 0) || (StrCmp (VariableName, EFI_IMAGE_SECURITY_DATABASE1) == 0))
> +           || (StrCmp (VariableName, EFI_IMAGE_SECURITY_DATABASE2)) == 0) {

Simply replacing the individual expressions with the predicates
"GuidMatch", "DbMatch", "DbxMatch", and "DbtMatch", the above
transformation becomes:

> -  } else if (GuidMatch &&
> -          ((DbMatch) || (DbxMatch))) {
> +  } else if (GuidMatch &&
> +          ((DbMatch) || (DbxMatch))
> +           || DbtMatch) {

In shorter form, we change

  GuidMatch && (DbMatch || DbxMatch)

into

  GuidMatch && (DbMatch || DbxMatch) || DbtMatch

which is incorrect, because this way "dbt" will match outside of the
intended namespace / GUID.

The error was caught by gcc:

> SecurityPkg/VariableAuthenticated/RuntimeDxe/Variable.c: In function
> 'VariableServiceSetVariable':
>
> SecurityPkg/VariableAuthenticated/RuntimeDxe/Variable.c:3188:71: error:
> suggest parentheses around '&&' within '||' [-Werror=parentheses]
>
>    } else if (CompareGuid (VendorGuid, &gEfiImageSecurityDatabaseGuid) &&
>                                                                        ^
> cc1: all warnings being treated as errors

Fix the parentheses.

This change may have security implications.

Contributed-under: TianoCore Contribution Agreement 1.0

Signed-off-by: Laszlo Ersek <lersek@redhat.com>

Reviewed-by: Qin Long <qin.long@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@16389 6f19259b-4bc3-4df7-8a09-765794883524

1 files changed, 5 insertions, 2 deletions

diff --git a/SecurityPkg/VariableAuthenticated/RuntimeDxe/Variable.c b/SecurityPkg/VariableAuthenticated/RuntimeDxe/Variable.c
index 432531f6df..ac043d9a17 100644
--- a/SecurityPkg/VariableAuthenticated/RuntimeDxe/Variable.c
+++ b/SecurityPkg/VariableAuthenticated/RuntimeDxe/Variable.c
@@ -3186,8 +3186,11 @@ VariableServiceSetVariable (
   } else if (CompareGuid (VendorGuid, &gEfiGlobalVariableGuid) && (StrCmp (VariableName, EFI_KEY_EXCHANGE_KEY_NAME) == 0)) {

     Status = ProcessVarWithPk (VariableName, VendorGuid, Data, DataSize, &Variable, Attributes, FALSE);

   } else if (CompareGuid (VendorGuid, &gEfiImageSecurityDatabaseGuid) &&

-          ((StrCmp (VariableName, EFI_IMAGE_SECURITY_DATABASE) == 0) || (StrCmp (VariableName, EFI_IMAGE_SECURITY_DATABASE1) == 0))

-           || (StrCmp (VariableName, EFI_IMAGE_SECURITY_DATABASE2)) == 0) {

+             ((StrCmp (VariableName, EFI_IMAGE_SECURITY_DATABASE)  == 0) ||

+              (StrCmp (VariableName, EFI_IMAGE_SECURITY_DATABASE1) == 0) ||

+              (StrCmp (VariableName, EFI_IMAGE_SECURITY_DATABASE2) == 0)

+             )

+            ) {

     Status = ProcessVarWithPk (VariableName, VendorGuid, Data, DataSize, &Variable, Attributes, FALSE);

     if (EFI_ERROR (Status)) {

       Status = ProcessVarWithKek (VariableName, VendorGuid, Data, DataSize, &Variable, Attributes);