MdeModulePkg: Replace BSD License with BSD+Patent License

[mirror_edk2.git] / MdeModulePkg / Core / Dxe / Misc / InstallConfigurationTable.c

diff --git a/MdeModulePkg/Core/Dxe/Misc/InstallConfigurationTable.c b/MdeModulePkg/Core/Dxe/Misc/InstallConfigurationTable.c
old mode 100644 (file)
new mode 100755 (executable)
index 82ac866..ba4e55f
--- a/MdeModulePkg/Core/Dxe/Misc/InstallConfigurationTable.c
+++ b/MdeModulePkg/Core/Dxe/Misc/InstallConfigurationTable.c
@@ -1,14 +1,8 @@
 /** @file\r
   UEFI Miscellaneous boot Services InstallConfigurationTable service\r
 \r
-Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>\r
-This program and the accompanying materials\r
-are licensed and made available under the terms and conditions of the BSD License\r
-which accompanies this distribution.  The full text of the license may be found at\r
-http://opensource.org/licenses/bsd-license.php\r
-\r
-THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
-WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
+Copyright (c) 2006 - 2017, Intel Corporation. All rights reserved.<BR>\r
+SPDX-License-Identifier: BSD-2-Clause-Patent\r
 \r
 **/\r
 \r
@@ -28,7 +22,7 @@ UINTN mSystemTableAllocateSize = 0;
                          update, or remove, may be NULL.\r
 \r
   @return EFI_SUCCESS               Guid, Table pair added, updated, or removed.\r
-  @return EFI_INVALID_PARAMETER     Input GUID not valid.\r
+  @return EFI_INVALID_PARAMETER     Input GUID is NULL.\r
   @return EFI_NOT_FOUND             Attempted to delete non-existant entry\r
   @return EFI_OUT_OF_RESOURCES      Not enough memory available\r
 \r
@@ -42,6 +36,7 @@ CoreInstallConfigurationTable (
 {\r
   UINTN                   Index;\r
   EFI_CONFIGURATION_TABLE *EfiConfigurationTable;\r
+  EFI_CONFIGURATION_TABLE *OldTable;\r
 \r
   //\r
   // If Guid is NULL, then this operation cannot be performed\r
@@ -68,7 +63,7 @@ CoreInstallConfigurationTable (
     if (Table != NULL) {\r
       //\r
       // If Table is not NULL, then this is a modify operation.\r
-      // Modify the table enty and return.\r
+      // Modify the table entry and return.\r
       //\r
       gDxeCoreST->ConfigurationTable[Index].VendorTable = Table;\r
 \r
@@ -134,15 +129,30 @@ CoreInstallConfigurationTable (
           );\r
 \r
         //\r
-        // Free Old Table\r
+        // Record the old table pointer.\r
         //\r
-        CoreFreePool (gDxeCoreST->ConfigurationTable);\r
-      }\r
+        OldTable = gDxeCoreST->ConfigurationTable;\r
 \r
-      //\r
-      // Update System Table\r
-      //\r
-      gDxeCoreST->ConfigurationTable = EfiConfigurationTable;\r
+        //\r
+        // As the CoreInstallConfigurationTable() may be re-entered by CoreFreePool()\r
+        // in its calling stack, updating System table to the new table pointer must\r
+        // be done before calling CoreFreePool() to free the old table.\r
+        // It can make sure the gDxeCoreST->ConfigurationTable point to the new table\r
+        // and avoid the errors of use-after-free to the old table by the reenter of\r
+        // CoreInstallConfigurationTable() in CoreFreePool()'s calling stack.\r
+        //\r
+        gDxeCoreST->ConfigurationTable = EfiConfigurationTable;\r
+\r
+        //\r
+        // Free the old table after updating System Table to the new table pointer.\r
+        //\r
+        CoreFreePool (OldTable);\r
+      } else {\r
+        //\r
+        // Update System Table\r
+        //\r
+        gDxeCoreST->ConfigurationTable = EfiConfigurationTable;\r
+      }\r
     }\r
 \r
     //\r