ArmPkg/UncachedMemoryAllocationLib: map uncached allocations non-executable

The primary use case for UncachedMemoryAllocationLib is non-coherent DMA,
which implies that such regions are not used to fetch instructions from.

So let's map them as non-executable, to avoid creating a security hole
when the rest of the platform may be enforcing strict memory permissions
on ordinary allocations.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Leif Lindholm <leif.lindholm@linaro.org>

diff --git a/ArmPkg/Library/UncachedMemoryAllocationLib/UncachedMemoryAllocationLib.c b/ArmPkg/Library/UncachedMemoryAllocationLib/UncachedMemoryAllocationLib.c
index 0d8abad2343379d24533ee6552ed1705fc3cba0e..b4fbfbcb362bf4656e9e931c7453f12cf2d60cca 100644 (file)
--- a/ArmPkg/Library/UncachedMemoryAllocationLib/UncachedMemoryAllocationLib.c
+++ b/ArmPkg/Library/UncachedMemoryAllocationLib/UncachedMemoryAllocationLib.c
@@ -154,7 +154,8 @@ AllocatePagesFromList (
     return Status;\r
   }\r
 \r
     return Status;\r
   }\r
 \r

-  Status = gDS->SetMemorySpaceAttributes (Memory, EFI_PAGES_TO_SIZE (Pages), EFI_MEMORY_WC);\r
+  Status = gDS->SetMemorySpaceAttributes (Memory, EFI_PAGES_TO_SIZE (Pages),\r
+                  EFI_MEMORY_WC | EFI_MEMORY_XP);\r

   if (EFI_ERROR (Status)) {\r
     gBS->FreePages (Memory, Pages);\r
     return Status;\r
   if (EFI_ERROR (Status)) {\r
     gBS->FreePages (Memory, Pages);\r
     return Status;\r