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| author | Jian J Wang <jian.j.wang@intel.com> | 2018-01-29 20:03:33 +0800 |
|---|---|---|
| committer | Star Zeng <star.zeng@intel.com> | 2018-02-02 09:50:16 +0800 |
| commit | a6a0a59756173148099d66638fcb4b3bca52434b (patch) | |
| tree | 2c4055fc940cbf9d7e6f3870aee4a3b88db19c63 | |
| parent | 9b17c6511d50db493c49324aaf81c50c3676a111 (diff) | |
| download | edk2-a6a0a59756173148099d66638fcb4b3bca52434b.tar.gz edk2-a6a0a59756173148099d66638fcb4b3bca52434b.tar.bz2 edk2-a6a0a59756173148099d66638fcb4b3bca52434b.zip | |
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>
| -rw-r--r-- | MdeModulePkg/Core/Dxe/Mem/HeapGuard.c | 14 | ||||
| -rw-r--r-- | MdeModulePkg/Core/Dxe/Mem/HeapGuard.h | 10 | ||||
| -rw-r--r-- | MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c | 22 |
3 files changed, 46 insertions, 0 deletions
diff --git a/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c b/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c index 392aeb8a02..d7906e08c5 100644 --- a/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c +++ b/MdeModulePkg/Core/Dxe/Mem/HeapGuard.c @@ -729,6 +729,20 @@ IsPageTypeToGuard ( }
/**
+ Check to see if the heap guard is enabled for page and/or pool allocation.
+
+ @return TRUE/FALSE.
+**/
+BOOLEAN
+IsHeapGuardEnabled (
+ VOID
+ )
+{
+ return IsMemoryTypeToGuard (EfiMaxMemoryType, AllocateAnyPages,
+ GUARD_HEAP_TYPE_POOL|GUARD_HEAP_TYPE_PAGE);
+}
+
+/**
Set head Guard and tail Guard for the given memory range.
@param[in] Memory Base address of memory to set guard for.
diff --git a/MdeModulePkg/Core/Dxe/Mem/HeapGuard.h b/MdeModulePkg/Core/Dxe/Mem/HeapGuard.h index 30ac0e678f..7208ab1437 100644 --- a/MdeModulePkg/Core/Dxe/Mem/HeapGuard.h +++ b/MdeModulePkg/Core/Dxe/Mem/HeapGuard.h @@ -389,6 +389,16 @@ AdjustPoolHeadF ( IN EFI_PHYSICAL_ADDRESS Memory
);
+/**
+ Check to see if the heap guard is enabled for page and/or pool allocation.
+
+ @return TRUE/FALSE.
+**/
+BOOLEAN
+IsHeapGuardEnabled (
+ VOID
+ );
+
extern BOOLEAN mOnGuarding;
#endif
diff --git a/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c b/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c index a4705bc7ce..455ed35f9a 100644 --- 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>
#include "DxeMain.h"
+#include "Mem/HeapGuard.h"
#define CACHE_ATTRIBUTE_MASK (EFI_MEMORY_UC | EFI_MEMORY_WC | EFI_MEMORY_WT | EFI_MEMORY_WB | EFI_MEMORY_UCE | EFI_MEMORY_WP)
#define MEMORY_ATTRIBUTE_MASK (EFI_MEMORY_RP | EFI_MEMORY_XP | EFI_MEMORY_RO)
@@ -1203,6 +1204,27 @@ ApplyMemoryProtectionPolicy ( }
//
+ // Don't overwrite Guard pages, which should be the first and/or last page,
+ // if any.
+ //
+ if (IsHeapGuardEnabled ()) {
+ if (IsGuardPage (Memory)) {
+ Memory += EFI_PAGE_SIZE;
+ Length -= EFI_PAGE_SIZE;
+ if (Length == 0) {
+ return EFI_SUCCESS;
+ }
+ }
+
+ if (IsGuardPage (Memory + Length - EFI_PAGE_SIZE)) {
+ Length -= EFI_PAGE_SIZE;
+ if (Length == 0) {
+ return EFI_SUCCESS;
+ }
+ }
+ }
+
+ //
// Update the executable permissions according to the DXE memory
// protection policy, but only if
// - the policy is different between the old and the new type, or
|