GetMemoryRegion() is used to obtain the attributes of an existing
mapping, to permit permission attribute changes to be optimized
away if the attributes don't actually change.
The current ARM code assumes that a section mapping or a page mapping
exists for any region passed into GetMemoryRegion(), but the region
may be unmapped entirely, in which case the code will crash. So check
if a section mapping exists before dereferencing it.
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ard Biesheuvel <ard.biesheu...@linaro.org>
---
ArmPkg/Drivers/CpuDxe/Arm/Mmu.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/ArmPkg/Drivers/CpuDxe/Arm/Mmu.c b/ArmPkg/Drivers/CpuDxe/Arm/Mmu.c
index 12ca5b26673e..3b29d33d0a9c 100644
--- a/ArmPkg/Drivers/CpuDxe/Arm/Mmu.c
+++ b/ArmPkg/Drivers/CpuDxe/Arm/Mmu.c
@@ -457,6 +457,9 @@ GetMemoryRegion (
// Get the section at the given index
SectionDescriptor = FirstLevelTable[TableIndex];
+ if (!SectionDescriptor) {
+ return EFI_NOT_FOUND;
+ }
// If 'BaseAddress' belongs to the section then round it to the section
boundary
if (((SectionDescriptor & TT_DESCRIPTOR_SECTION_TYPE_MASK) ==
TT_DESCRIPTOR_SECTION_TYPE_SECTION) ||
--
2.19.1
_______________________________________________
edk2-devel mailing list
edk2-devel@lists.01.org
https://lists.01.org/mailman/listinfo/edk2-devel
