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SecurityPkg: Make time based AuthVariable update atomic 

System may break during time based AuthVariable update, causing certdb inconsistent. 2 ways are used to ensure update atomic.
 1. Delete cert in certdb after variable is deleted
 2. Clean up certdb on variable initialization

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Chao Zhang <chao.b.zhang@intel.com>
Reviewed-by: Yao Jiewen <jiewen.yao@intel.com>
Reviewed-by: Star Zeng <star.zeng@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@17919 6f19259b-4bc3-4df7-8a09-765794883524
This commit is contained in:
Chao Zhang 2015-07-10 06:20:04 +00:00 committed by czhang46
parent cfa451c84a
commit 64b6a3ff4a
3 changed files with 170 additions and 30 deletions
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175
SecurityPkg/Library/AuthVariableLib/AuthService.c
View File

@ -1205,18 +1205,17 @@ ProcessVariable (
//
// Allow the delete operation of common authenticated variable at user physical presence.
//
if ((Attributes & EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) != 0) {
Status = AuthServiceInternalUpdateVariable (
VariableName,
VendorGuid,
NULL,
0,
0
);
if (!EFI_ERROR (Status) && ((Attributes & EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) != 0)) {
Status = DeleteCertsFromDb (VariableName, VendorGuid);
}
if (!EFI_ERROR (Status)) {
Status = AuthServiceInternalUpdateVariable (
VariableName,
VendorGuid,
NULL,
0,
0
);
}
return Status;
}
@ -1964,6 +1963,109 @@ InsertCertsToDb (
return Status;
}
/**
Clean up signer's certificates for common authenticated variable
by corresponding VariableName and VendorGuid from "certdb".
Sytem may break down during Timebased Variable update & certdb update,
make them inconsistent, this function is called in AuthVariable Init to ensure
consistency
@retval EFI_NOT_FOUND Fail to find matching certs.
@retval EFI_SUCCESS Find matching certs and output parameters.
**/
EFI_STATUS
CleanCertsFromDb (
VOID
){
UINT32 Offset;
AUTH_CERT_DB_DATA *Ptr;
UINT32 NameSize;
UINT32 NodeSize;
CHAR16 *VariableName;
EFI_STATUS Status;
BOOLEAN CertCleaned;
UINT8 *Data;
UINTN DataSize;
UINT8 *AuthVarData;
UINTN AuthVarDataSize;
EFI_GUID AuthVarGuid;
Status = EFI_SUCCESS;
//
// Get corresponding certificates by VendorGuid and VariableName.
//
do {
CertCleaned = FALSE;
//
// Get latest variable "certdb"
//
Status = AuthServiceInternalFindVariable (
EFI_CERT_DB_NAME,
&gEfiCertDbGuid,
(VOID **) &Data,
&DataSize
);
if (EFI_ERROR (Status)) {
return Status;
}
if ((DataSize == 0) || (Data == NULL)) {
ASSERT (FALSE);
return EFI_NOT_FOUND;
}
Offset = sizeof (UINT32);
while (Offset < (UINT32) DataSize) {
Ptr = (AUTH_CERT_DB_DATA *) (Data + Offset);
//
// Check whether VendorGuid matches.
//
NodeSize = ReadUnaligned32 (&Ptr->CertNodeSize);
NameSize = ReadUnaligned32 (&Ptr->NameSize);
//
// Get VarName tailed with '\0'
//
VariableName = AllocateZeroPool((NameSize + 1) * sizeof(CHAR16));
if (VariableName == NULL) {
return EFI_OUT_OF_RESOURCES;
}
CopyMem (VariableName, (UINT8 *) Ptr + sizeof (AUTH_CERT_DB_DATA), NameSize * sizeof(CHAR16));
//
// Keep VarGuid aligned
//
CopyMem (&AuthVarGuid, &Ptr->VendorGuid, sizeof(EFI_GUID));
//
// Find corresponding time auth variable
//
Status = AuthServiceInternalFindVariable (
VariableName,
&AuthVarGuid,
(VOID **) &AuthVarData,
&AuthVarDataSize
);
if (EFI_ERROR(Status)) {
Status = DeleteCertsFromDb(VariableName, &AuthVarGuid);
CertCleaned = TRUE;
DEBUG((EFI_D_INFO, "Recovery!! Cert for Auth Variable %s Guid %g is removed for consistency\n", VariableName, &AuthVarGuid));
FreePool(VariableName);
break;
}
FreePool(VariableName);
Offset = Offset + NodeSize;
}
} while (CertCleaned);
return Status;
}
/**
Process variable with EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS set
@ -2285,16 +2387,7 @@ VerifyTimeBasedPayload (
goto Exit;
}
//
// Delete signer's certificates when delete the common authenticated variable.
//
if ((PayloadSize == 0) && (OrgTimeStamp != NULL) && ((Attributes & EFI_VARIABLE_APPEND_WRITE) == 0)) {
Status = DeleteCertsFromDb (VariableName, VendorGuid);
if (EFI_ERROR (Status)) {
VerifyStatus = FALSE;
goto Exit;
}
} else if ((OrgTimeStamp == NULL) && (PayloadSize != 0)) {
if ((OrgTimeStamp == NULL) && (PayloadSize != 0)) {
//
// Insert signer's certificates when adding a new common authenticated variable.
//
@ -2389,6 +2482,7 @@ VerifyTimeBasedPayloadAndUpdate (
UINTN PayloadSize;
EFI_VARIABLE_AUTHENTICATION_2 *CertData;
AUTH_VARIABLE_INFO OrgVariableInfo;
BOOLEAN IsDel;
ZeroMem (&OrgVariableInfo, sizeof (OrgVariableInfo));
FindStatus = mAuthVarLibContextIn->FindVariable (
@ -2412,8 +2506,12 @@ VerifyTimeBasedPayloadAndUpdate (
return Status;
}
if ((PayloadSize == 0) && (VarDel != NULL)) {
*VarDel = TRUE;
if (!EFI_ERROR(FindStatus)
&& (PayloadSize == 0)
&& ((Attributes & EFI_VARIABLE_APPEND_WRITE) == 0)) {
IsDel = TRUE;
} else {
IsDel = FALSE;
}
CertData = (EFI_VARIABLE_AUTHENTICATION_2 *) Data;
@ -2421,12 +2519,29 @@ VerifyTimeBasedPayloadAndUpdate (
//
// Final step: Update/Append Variable if it pass Pkcs7Verify
//
return AuthServiceInternalUpdateVariableWithTimeStamp (
VariableName,
VendorGuid,
PayloadPtr,
PayloadSize,
Attributes,
&CertData->TimeStamp
);
Status = AuthServiceInternalUpdateVariableWithTimeStamp (
VariableName,
VendorGuid,
PayloadPtr,
PayloadSize,
Attributes,
&CertData->TimeStamp
);
//
// Delete signer's certificates when delete the common authenticated variable.
//
if (IsDel && AuthVarType == AuthVarTypePriv && !EFI_ERROR(Status) ) {
Status = DeleteCertsFromDb (VariableName, VendorGuid);
}
if (VarDel != NULL) {
if (IsDel && !EFI_ERROR(Status)) {
*VarDel = TRUE;
} else {
*VarDel = FALSE;
}
}
return Status;
}

16
SecurityPkg/Library/AuthVariableLib/AuthServiceInternal.h
View File

@ -186,6 +186,22 @@ DeleteCertsFromDb (
IN EFI_GUID *VendorGuid
);
/**
Clean up signer's certificates for common authenticated variable
by corresponding VariableName and VendorGuid from "certdb".
Sytem may break down during Timebased Variable update & certdb update,
make them inconsistent, this function is called in AuthVariable Init to ensure
consistency
@retval EFI_NOT_FOUND Fail to find matching certs.
@retval EFI_SUCCESS Find matching certs and output parameters.
**/
EFI_STATUS
CleanCertsFromDb (
VOID
);
/**
Filter out the duplicated EFI_SIGNATURE_DATA from the new data by comparing to the original data.

9
SecurityPkg/Library/AuthVariableLib/AuthVariableLib.c
View File

@ -352,6 +352,15 @@ AuthVariableLibInitialize (
if (EFI_ERROR (Status)) {
return Status;
}
} else {
//
// Clean up Certs to make certDB & Time based auth variable consistent
//
Status = CleanCertsFromDb();
if (EFI_ERROR (Status)) {
DEBUG ((EFI_D_INFO, "Clean up CertDB fail! Status %x\n", Status));
return Status;
}
}
//