SecurityPkg OpalPasswordSupportLib: Add check to avoid potential buffer overflow.

Current code not check the CommunicationBuffer size before use it. Attacker can
read beyond the end of the (untrusted) commbuffer into controlled memory. Attacker
can get access outside of valid SMM memory regions. This patch add check before
use it.

bugz: https://bugzilla.tianocore.org/show_bug.cgi?id=198

Cc: Yao Jiewen <jiewen.yao@intel.com>
Cc: Wu Hao <hao.a.wu@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Eric Dong <eric.dong@intel.com>
Reviewed-by: Yao Jiewen <jiewen.yao@intel.com>

SecurityPkg/Include/Library/OpalPasswordSupportLib.h

@@ -19,6 +19,7 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 #include <Protocol/DevicePath.h>
 #include <Library/TcgStorageOpalLib.h>
 
+#define OPAL_PASSWORD_MAX_LENGTH         32
 
 #pragma pack(1)
 
@@ -76,7 +77,7 @@ typedef struct {
 typedef struct {
   LIST_ENTRY                 Link;
 
-  UINT8                      Password[32];
+  UINT8                      Password[OPAL_PASSWORD_MAX_LENGTH];
   UINT8                      PasswordLength;
 
   EFI_DEVICE_PATH_PROTOCOL   OpalDevicePath;

SecurityPkg/Library/OpalPasswordSupportLib/OpalPasswordSupportLib.c

@@ -14,8 +14,6 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 
 #include "OpalPasswordSupportNotify.h"
 
-#define OPAL_PASSWORD_MAX_LENGTH         32
-
 LIST_ENTRY           mDeviceList = INITIALIZE_LIST_HEAD_VARIABLE (mDeviceList);
 BOOLEAN              gInSmm = FALSE;
 EFI_GUID             gOpalPasswordNotifyProtocolGuid = OPAL_PASSWORD_NOTIFY_PROTOCOL_GUID;
@@ -663,34 +661,53 @@ SmmOpalPasswordHandler (
   EFI_STATUS                        Status;
   OPAL_SMM_COMMUNICATE_HEADER       *SmmFunctionHeader;
   UINTN                             TempCommBufferSize;
-  UINT8                             *NewPassword;
+  UINTN                             RemainedDevicePathSize;
-  UINT8                             PasswordLength;
+  OPAL_COMM_DEVICE_LIST             *DeviceBuffer;
-  EFI_DEVICE_PATH_PROTOCOL          *DevicePath;
 
   if (CommBuffer == NULL || CommBufferSize == NULL) {
     return EFI_SUCCESS;
   }
 
+  Status = EFI_SUCCESS;
+  DeviceBuffer = NULL;
+
   TempCommBufferSize = *CommBufferSize;
   if (TempCommBufferSize < OFFSET_OF (OPAL_SMM_COMMUNICATE_HEADER, Data)) {
     return EFI_SUCCESS;
   }
-
+  SmmFunctionHeader = (OPAL_SMM_COMMUNICATE_HEADER *)CommBuffer;
-  Status   = EFI_SUCCESS;
-  SmmFunctionHeader     = (OPAL_SMM_COMMUNICATE_HEADER *)CommBuffer;
-
-  DevicePath = &((OPAL_COMM_DEVICE_LIST*)(SmmFunctionHeader->Data))->OpalDevicePath;
-  PasswordLength = ((OPAL_COMM_DEVICE_LIST*)(SmmFunctionHeader->Data))->PasswordLength;
-  NewPassword = ((OPAL_COMM_DEVICE_LIST*)(SmmFunctionHeader->Data))->Password;
 
   switch (SmmFunctionHeader->Function) {
     case SMM_FUNCTION_SET_OPAL_PASSWORD:
-        if (OpalPasswordIsFullZero (NewPassword) || PasswordLength == 0) {
+      if (TempCommBufferSize <= OFFSET_OF (OPAL_SMM_COMMUNICATE_HEADER, Data) + OFFSET_OF (OPAL_COMM_DEVICE_LIST, OpalDevicePath)) {
-          Status = EFI_INVALID_PARAMETER;
+        return EFI_SUCCESS;
-          goto EXIT;
+      }
-        }
 
-        Status = OpalSavePasswordToSmm (DevicePath, NewPassword, PasswordLength);
+      DeviceBuffer = AllocateCopyPool (TempCommBufferSize - OFFSET_OF (OPAL_SMM_COMMUNICATE_HEADER, Data), SmmFunctionHeader->Data);
+      if (DeviceBuffer == NULL) {
+        Status = EFI_OUT_OF_RESOURCES;
+        goto EXIT;
+      }
+
+      //
+      // Validate the DevicePath.
+      //
+      RemainedDevicePathSize = TempCommBufferSize - OFFSET_OF (OPAL_SMM_COMMUNICATE_HEADER, Data)
+                                    - OFFSET_OF (OPAL_COMM_DEVICE_LIST, OpalDevicePath);
+      if (!IsDevicePathValid(&DeviceBuffer->OpalDevicePath, RemainedDevicePathSize) ||
+          (RemainedDevicePathSize != GetDevicePathSize (&DeviceBuffer->OpalDevicePath))) {
+        Status = EFI_SUCCESS;
+        goto EXIT;
+      }
+
+      if (OpalPasswordIsFullZero (DeviceBuffer->Password) ||
+          DeviceBuffer->PasswordLength == 0 ||
+          DeviceBuffer->PasswordLength > OPAL_PASSWORD_MAX_LENGTH) {
+        Status = EFI_INVALID_PARAMETER;
+        goto EXIT;
+      }
+
+      Status = OpalSavePasswordToSmm (&DeviceBuffer->OpalDevicePath, DeviceBuffer->Password, DeviceBuffer->PasswordLength);
       break;
 
     default:
@@ -701,6 +718,10 @@ SmmOpalPasswordHandler (
 EXIT:
   SmmFunctionHeader->ReturnStatus = Status;
 
+  if (DeviceBuffer != NULL) {
+    FreePool (DeviceBuffer);
+  }
+
   //
   // Return EFI_SUCCESS cause only one handler can be trigged.
   // so return EFI_WARN_INTERRUPT_SOURCE_PENDING to make all handler can be trigged.

SecurityPkg/Library/OpalPasswordSupportLib/OpalPasswordSupportNotify.h

@@ -41,7 +41,7 @@ typedef struct {
 } OPAL_SMM_COMMUNICATE_HEADER;
 
 typedef struct {
-  UINT8                      Password[32];
+  UINT8                      Password[OPAL_PASSWORD_MAX_LENGTH];
   UINT8                      PasswordLength;
 
   EFI_DEVICE_PATH_PROTOCOL   OpalDevicePath;

SecurityPkg/Tcg/Opal/OpalPasswordSmm/OpalPasswordSmm.h

@@ -64,10 +64,6 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 // The payload Length of HDD related ATA commands
 //
 #define HDD_PAYLOAD                      512
-//
-// According to ATA spec, the max Length of hdd password is 32 bytes
-//
-#define OPAL_PASSWORD_MAX_LENGTH         32
 
 extern VOID                              *mBuffer;
 
@@ -124,7 +120,7 @@ typedef struct {
 
   UINT32                                   NvmeNamespaceId;
 
-  UINT8                                    Password[32];
+  UINT8                                    Password[OPAL_PASSWORD_MAX_LENGTH];
   UINT8                                    PasswordLength;
 
   UINT32                                   Length;