MdeModulePkg/Core: fix feature conflict between NX and heap guard

Considering following scenario (both NX memory protection and heap guard
are enabled):

   1. Allocate 3 pages. The attributes of adjacent memory pages will be

      |NOT-PRESENT|  present  |  present  |  present  |NOT-PRESENT|

   2. Free the middle page. The attributes of adjacent memory pages should be

      |NOT-PRESENT|  present  |NOT-PRESENT|  present  |NOT-PRESENT|

      But the NX feature will overwrite the attributes of middle page. So it
      looks still like below, which is wrong.

      |NOT-PRESENT|  present  |  PRESENT  |  present  |NOT-PRESENT|

The solution is checking the first and/or last page of a memory block to be
marked as NX, and skipping them if they are Guard pages.

Cc: Star Zeng <star.zeng@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Jian J Wang <jian.j.wang@intel.com>
Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>

diff --git a/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c b/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c
index 392aeb8a0210f1cee6cf94029efe16e9890ca818..d7906e08c53c4f795aaf05fe5b0207eb1b1d84e7 100644 (file)
--- a/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c
+++ b/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c
@@ -728,6 +728,20 @@ IsPageTypeToGuard (
   return IsMemoryTypeToGuard (MemoryType, AllocateType, GUARD_HEAP_TYPE_PAGE);\r
 }\r
 \r
   return IsMemoryTypeToGuard (MemoryType, AllocateType, GUARD_HEAP_TYPE_PAGE);\r
 }\r
 \r

+/**\r
+  Check to see if the heap guard is enabled for page and/or pool allocation.\r
+\r
+  @return TRUE/FALSE.\r
+**/\r
+BOOLEAN\r
+IsHeapGuardEnabled (\r
+  VOID\r
+  )\r
+{\r
+  return IsMemoryTypeToGuard (EfiMaxMemoryType, AllocateAnyPages,\r
+                              GUARD_HEAP_TYPE_POOL|GUARD_HEAP_TYPE_PAGE);\r
+}\r
+\r

 /**\r
   Set head Guard and tail Guard for the given memory range.\r
 \r
 /**\r
   Set head Guard and tail Guard for the given memory range.\r
 \r

diff --git a/MdeModulePkg/Core/Dxe/Mem/HeapGuard.h b/MdeModulePkg/Core/Dxe/Mem/HeapGuard.h
index 30ac0e678f7784beee8f9bb2c5a620f08e96f603..7208ab143719a2b2923b9db97585d52de000f891 100644 (file)
--- a/MdeModulePkg/Core/Dxe/Mem/HeapGuard.h
+++ b/MdeModulePkg/Core/Dxe/Mem/HeapGuard.h
@@ -389,6 +389,16 @@ AdjustPoolHeadF (
   IN EFI_PHYSICAL_ADDRESS    Memory\r
   );\r
 \r
   IN EFI_PHYSICAL_ADDRESS    Memory\r
   );\r
 \r

+/**\r
+  Check to see if the heap guard is enabled for page and/or pool allocation.\r
+\r
+  @return TRUE/FALSE.\r
+**/\r
+BOOLEAN\r
+IsHeapGuardEnabled (\r
+  VOID\r
+  );\r
+\r

 extern BOOLEAN mOnGuarding;\r
 \r
 #endif\r
 extern BOOLEAN mOnGuarding;\r
 \r
 #endif\r

diff --git a/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c b/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c
index a4705bc7ce343f002fb933829e9cecfaa3ec7987..455ed35f9a36541272ea21effd7d13f23f5caf84 100644 (file)
--- a/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c
+++ b/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c
@@ -48,6 +48,7 @@ WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
 #include <Protocol/SimpleFileSystem.h>\r
 \r
 #include "DxeMain.h"\r
 #include <Protocol/SimpleFileSystem.h>\r
 \r
 #include "DxeMain.h"\r

+#include "Mem/HeapGuard.h"\r

 \r
 #define CACHE_ATTRIBUTE_MASK   (EFI_MEMORY_UC | EFI_MEMORY_WC | EFI_MEMORY_WT | EFI_MEMORY_WB | EFI_MEMORY_UCE | EFI_MEMORY_WP)\r
 #define MEMORY_ATTRIBUTE_MASK  (EFI_MEMORY_RP | EFI_MEMORY_XP | EFI_MEMORY_RO)\r
 \r
 #define CACHE_ATTRIBUTE_MASK   (EFI_MEMORY_UC | EFI_MEMORY_WC | EFI_MEMORY_WT | EFI_MEMORY_WB | EFI_MEMORY_UCE | EFI_MEMORY_WP)\r
 #define MEMORY_ATTRIBUTE_MASK  (EFI_MEMORY_RP | EFI_MEMORY_XP | EFI_MEMORY_RO)\r


@@ -1202,6 +1203,27 @@ ApplyMemoryProtectionPolicy (
     return EFI_SUCCESS;\r
   }\r
 \r
     return EFI_SUCCESS;\r
   }\r
 \r

+  //\r
+  // Don't overwrite Guard pages, which should be the first and/or last page,\r
+  // if any.\r
+  //\r
+  if (IsHeapGuardEnabled ()) {\r
+    if (IsGuardPage (Memory))  {\r
+      Memory += EFI_PAGE_SIZE;\r
+      Length -= EFI_PAGE_SIZE;\r
+      if (Length == 0) {\r
+        return EFI_SUCCESS;\r
+      }\r
+    }\r
+\r
+    if (IsGuardPage (Memory + Length - EFI_PAGE_SIZE))  {\r
+      Length -= EFI_PAGE_SIZE;\r
+      if (Length == 0) {\r
+        return EFI_SUCCESS;\r
+      }\r
+    }\r
+  }\r
+\r

   //\r
   // Update the executable permissions according to the DXE memory\r
   // protection policy, but only if\r
   //\r
   // Update the executable permissions according to the DXE memory\r
   // protection policy, but only if\r