MdeModulePkg/PiSmmCore: fix #PF caused by freeing read-only memory

[mirror_edk2.git] / MdeModulePkg / Core / PiSmmCore / HeapGuard.c

diff --git a/MdeModulePkg/Core/PiSmmCore/HeapGuard.c b/MdeModulePkg/Core/PiSmmCore/HeapGuard.c
index c5ffb263420e0a3d37e1de9d9825c96ce87f1a17..d5556eb79cb1cfd73ba1569fe8c9e2ee02708cbb 100644 (file)
--- a/MdeModulePkg/Core/PiSmmCore/HeapGuard.c
+++ b/MdeModulePkg/Core/PiSmmCore/HeapGuard.c
@@ -1,7 +1,7 @@
 /** @file\r
   UEFI Heap Guard functions.\r
 \r
-Copyright (c) 2017, Intel Corporation. All rights reserved.<BR>\r
+Copyright (c) 2017-2018, 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
@@ -73,7 +73,7 @@ SetBits (
   StartBit  = (UINTN)GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address);\r
   EndBit    = (StartBit + BitNumber - 1) % GUARDED_HEAP_MAP_ENTRY_BITS;\r
 \r
-  if ((StartBit + BitNumber) > GUARDED_HEAP_MAP_ENTRY_BITS) {\r
+  if ((StartBit + BitNumber) >= GUARDED_HEAP_MAP_ENTRY_BITS) {\r
     Msbs    = (GUARDED_HEAP_MAP_ENTRY_BITS - StartBit) %\r
               GUARDED_HEAP_MAP_ENTRY_BITS;\r
     Lsbs    = (EndBit + 1) % GUARDED_HEAP_MAP_ENTRY_BITS;\r
@@ -126,7 +126,7 @@ ClearBits (
   StartBit  = (UINTN)GUARDED_HEAP_MAP_ENTRY_BIT_INDEX (Address);\r
   EndBit    = (StartBit + BitNumber - 1) % GUARDED_HEAP_MAP_ENTRY_BITS;\r
 \r
-  if ((StartBit + BitNumber) > GUARDED_HEAP_MAP_ENTRY_BITS) {\r
+  if ((StartBit + BitNumber) >= GUARDED_HEAP_MAP_ENTRY_BITS) {\r
     Msbs    = (GUARDED_HEAP_MAP_ENTRY_BITS - StartBit) %\r
               GUARDED_HEAP_MAP_ENTRY_BITS;\r
     Lsbs    = (EndBit + 1) % GUARDED_HEAP_MAP_ENTRY_BITS;\r
@@ -191,10 +191,14 @@ GetBits (
     Lsbs = 0;\r
   }\r
 \r
-  Result    = RShiftU64 ((*BitMap), StartBit) & (LShiftU64 (1, Msbs) - 1);\r
-  if (Lsbs > 0) {\r
-    BitMap  += 1;\r
-    Result  |= LShiftU64 ((*BitMap) & (LShiftU64 (1, Lsbs) - 1), Msbs);\r
+  if (StartBit == 0 && BitNumber == GUARDED_HEAP_MAP_ENTRY_BITS) {\r
+    Result = *BitMap;\r
+  } else {\r
+    Result    = RShiftU64((*BitMap), StartBit) & (LShiftU64(1, Msbs) - 1);\r
+    if (Lsbs > 0) {\r
+      BitMap  += 1;\r
+      Result  |= LShiftU64 ((*BitMap) & (LShiftU64 (1, Lsbs) - 1), Msbs);\r
+    }\r
   }\r
 \r
   return Result;\r
@@ -251,8 +255,8 @@ FindGuardedMemoryMap (
   //\r
   // Adjust current map table depth according to the address to access\r
   //\r
-  while (mMapLevel < GUARDED_HEAP_MAP_TABLE_DEPTH\r
-         &&\r
+  while (AllocMapUnit &&\r
+         mMapLevel < GUARDED_HEAP_MAP_TABLE_DEPTH &&\r
          RShiftU64 (\r
            Address,\r
            mLevelShift[GUARDED_HEAP_MAP_TABLE_DEPTH - mMapLevel - 1]\r
@@ -887,11 +891,8 @@ AdjustMemoryS (
   }\r
 \r
   Target = Start + Size - SizeRequested;\r
-\r
-  //\r
-  // At least one more page needed for Guard page.\r
-  //\r
-  if (Size < (SizeRequested + EFI_PAGES_TO_SIZE (1))) {\r
+  ASSERT (Target >= Start);\r
+  if (Target == 0) {\r
     return 0;\r
   }\r
 \r
@@ -940,6 +941,7 @@ AdjustMemoryF (
   EFI_PHYSICAL_ADDRESS  MemoryToTest;\r
   UINTN                 PagesToFree;\r
   UINT64                GuardBitmap;\r
+  UINT64                Attributes;\r
 \r
   if (Memory == NULL || NumberOfPages == NULL || *NumberOfPages == 0) {\r
     return;\r
@@ -948,6 +950,27 @@ AdjustMemoryF (
   Start = *Memory;\r
   PagesToFree = *NumberOfPages;\r
 \r
+  //\r
+  // In case the memory to free is marked as read-only (e.g. EfiRuntimeServicesCode).\r
+  //\r
+  if (mSmmMemoryAttribute != NULL) {\r
+    Attributes = 0;\r
+    mSmmMemoryAttribute->GetMemoryAttributes (\r
+                           mSmmMemoryAttribute,\r
+                           Start,\r
+                           EFI_PAGES_TO_SIZE (PagesToFree),\r
+                           &Attributes\r
+                           );\r
+    if ((Attributes & EFI_MEMORY_RO) != 0) {\r
+      mSmmMemoryAttribute->ClearMemoryAttributes (\r
+                             mSmmMemoryAttribute,\r
+                             Start,\r
+                             EFI_PAGES_TO_SIZE (PagesToFree),\r
+                             EFI_MEMORY_RO\r
+                             );\r
+    }\r
+  }\r
+\r
   //\r
   // Head Guard must be one page before, if any.\r
   //\r