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| author | Jian J Wang <jian.j.wang@intel.com> | 2018-01-29 19:07:29 +0800 |
|---|---|---|
| committer | Star Zeng <star.zeng@intel.com> | 2018-02-02 09:50:16 +0800 |
| commit | 9b17c6511d50db493c49324aaf81c50c3676a111 (patch) | |
| tree | 477124e32d1842a64b472c5e7acc09b3b6b5db3a /MdeModulePkg | |
| parent | 1263ecf2ffc9302663a304e7a6467c6e00cebf4a (diff) | |
| download | edk2-9b17c6511d50db493c49324aaf81c50c3676a111.tar.gz edk2-9b17c6511d50db493c49324aaf81c50c3676a111.tar.bz2 edk2-9b17c6511d50db493c49324aaf81c50c3676a111.zip | |
MdeModulePkg/Core: fix feature conflict between NX and NULL detection
If enabled, NX memory protection feature will mark all free memory as
NX (non-executable), including page 0. This will overwrite the attributes
of page 0 if NULL pointer detection feature is also enabled and then
compromise the functionality of it. The solution is skipping the NX
attributes setting to page 0 if NULL pointer detection feature is enabled.
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>
Diffstat (limited to 'MdeModulePkg')
| -rw-r--r-- | MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c | 22 |
1 files changed, 18 insertions, 4 deletions
diff --git a/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c b/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c index 862593f562..a4705bc7ce 100644 --- a/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c +++ b/MdeModulePkg/Core/Dxe/Misc/MemoryProtection.c @@ -845,10 +845,24 @@ InitializeDxeNxMemoryProtectionPolicy ( Attributes = GetPermissionAttributeForMemoryType (MemoryMapEntry->Type);
if (Attributes != 0) {
- SetUefiImageMemoryAttributes (
- MemoryMapEntry->PhysicalStart,
- LShiftU64 (MemoryMapEntry->NumberOfPages, EFI_PAGE_SHIFT),
- Attributes);
+ if (MemoryMapEntry->PhysicalStart == 0 &&
+ PcdGet8 (PcdNullPointerDetectionPropertyMask) != 0) {
+
+ ASSERT (MemoryMapEntry->NumberOfPages > 0);
+ //
+ // Skip page 0 if NULL pointer detection is enabled to avoid attributes
+ // overwritten.
+ //
+ SetUefiImageMemoryAttributes (
+ MemoryMapEntry->PhysicalStart + EFI_PAGE_SIZE,
+ LShiftU64 (MemoryMapEntry->NumberOfPages - 1, EFI_PAGE_SHIFT),
+ Attributes);
+ } else {
+ SetUefiImageMemoryAttributes (
+ MemoryMapEntry->PhysicalStart,
+ LShiftU64 (MemoryMapEntry->NumberOfPages, EFI_PAGE_SHIFT),
+ Attributes);
+ }
}
MemoryMapEntry = NEXT_MEMORY_DESCRIPTOR (MemoryMapEntry, DescriptorSize);
}
|