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 <ler...@redhat.com>
---
 SecurityPkg/VariableAuthenticated/RuntimeDxe/Variable.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/SecurityPkg/VariableAuthenticated/RuntimeDxe/Variable.c 
b/SecurityPkg/VariableAuthenticated/RuntimeDxe/Variable.c
index 432531f..ac043d9 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);
-- 
1.8.3.1


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