Define a new fixed/patchable PCD that sets the DXE memory protection
policy: its primary use is to define which memory types should have
their executable permissions removed. Combined with the image protection
policy, this can be used to implement a strict W^X policy, i.e.. a policy
where no regions exist that are both executable and writable at the same
time.
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
MdeModulePkg/MdeModulePkg.dec | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/MdeModulePkg/MdeModulePkg.dec b/MdeModulePkg/MdeModulePkg.dec
index 426634fbbd4d..ea64cdf3772d 100644
--- a/MdeModulePkg/MdeModulePkg.dec
+++ b/MdeModulePkg/MdeModulePkg.dec
@@ -1107,6 +1107,22 @@ [PcdsFixedAtBuild, PcdsPatchableInModule]
# @ValidRange 0x80000002 | 0x00000000 - 0x0000001F
gEfiMdeModulePkgTokenSpaceGuid.PcdImageProtectionPolicy|0x00000002|UINT32|0x00001047
+ ## Set DXE memory protection policy. The policy is bitwise.
+ # If a bit is set, memory regions of the associated type will be mapped
+ # non-executable.<BR><BR>
+ # BIT0 - EfiLoaderData. <BR>
+ # - EfiBootServicesData. <BR>
+ # - EfiRuntimeServicesData. <BR>
+ # - EfiConventionalMemory. <BR>
+ # - EfiUnusableMemory. <BR>
+ # - EfiPersistentMemory. <BR>
+ # - EfiACPIReclaimMemory. <BR>
+ # BIT1 - EfiReservedMemoryType. <BR>
+ # BIT2 - EfiACPIMemoryNVS. <BR>
+ # @Prompt Set DXE memory protection policy.
+ # @ValidRange 0x80000002 | 0x00000000 - 0x00000007
+ gEfiMdeModulePkgTokenSpaceGuid.PcdDxeMemoryProtectionPolicy|0x0000007|UINT32|0x00001048
+
## PCI Serial Device Info. It is an array of Device, Function, and Power Management
# information that describes the path that contains zero or more PCI to PCI briges
# followed by a PCI serial device. Each array entry is 4-bytes in length. The
--
2.7.4
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