StandaloneMmPkg/Hob: Integer Overflow in CreateHob()

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4166

Fix integer overflow in various CreateHob instances.
Fixes: CVE-2022-36765

The CreateHob() function aligns the requested size to 8
performing the following operation:
```
HobLength = (UINT16)((HobLength + 0x7) & (~0x7));
```

No checks are performed to ensure this value doesn't
overflow, and could lead to CreateHob() returning a smaller
HOB than requested, which could lead to OOB HOB accesses.

Reported-by: Marc Beatove <mbeatove@google.com>
Reviewed-by: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Sami Mujawar <sami.mujawar@arm.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Cc: John Mathew <john.mathews@intel.com>
Authored-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Gua Guo <gua.guo@intel.com>

1 files changed, 35 insertions, 0 deletions

diff --git a/StandaloneMmPkg/Library/StandaloneMmCoreHobLib/Arm/StandaloneMmCoreHobLib.c b/StandaloneMmPkg/Library/StandaloneMmCoreHobLib/Arm/StandaloneMmCoreHobLib.c
index 1550e1babc..59473e28fe 100644
--- a/StandaloneMmPkg/Library/StandaloneMmCoreHobLib/Arm/StandaloneMmCoreHobLib.c
+++ b/StandaloneMmPkg/Library/StandaloneMmCoreHobLib/Arm/StandaloneMmCoreHobLib.c
@@ -34,6 +34,13 @@ CreateHob (
 

   HandOffHob = GetHobList ();

 

+  //

+  // Check Length to avoid data overflow.

+  //

+  if (HobLength > MAX_UINT16 - 0x7) {

+    return NULL;

+  }

+

   HobLength = (UINT16)((HobLength + 0x7) & (~0x7));

 

   FreeMemory = HandOffHob->EfiFreeMemoryTop - HandOffHob->EfiFreeMemoryBottom;

@@ -89,6 +96,10 @@ BuildModuleHob (
     );

 

   Hob = CreateHob (EFI_HOB_TYPE_MEMORY_ALLOCATION, sizeof (EFI_HOB_MEMORY_ALLOCATION_MODULE));

+  ASSERT (Hob != NULL);

+  if (Hob == NULL) {

+    return;

+  }

 

   CopyGuid (&(Hob->MemoryAllocationHeader.Name), &gEfiHobMemoryAllocModuleGuid);

   Hob->MemoryAllocationHeader.MemoryBaseAddress = MemoryAllocationModule;

@@ -129,6 +140,9 @@ BuildResourceDescriptorHob (
 

   Hob = CreateHob (EFI_HOB_TYPE_RESOURCE_DESCRIPTOR, sizeof (EFI_HOB_RESOURCE_DESCRIPTOR));

   ASSERT (Hob != NULL);

+  if (Hob == NULL) {

+    return;

+  }

 

   Hob->ResourceType      = ResourceType;

   Hob->ResourceAttribute = ResourceAttribute;

@@ -167,6 +181,11 @@ BuildGuidHob (
   ASSERT (DataLength <= (0xffff - sizeof (EFI_HOB_GUID_TYPE)));

 

   Hob = CreateHob (EFI_HOB_TYPE_GUID_EXTENSION, (UINT16)(sizeof (EFI_HOB_GUID_TYPE) + DataLength));

+  ASSERT (Hob != NULL);

+  if (Hob == NULL) {

+    return NULL;

+  }

+

   CopyGuid (&Hob->Name, Guid);

   return Hob + 1;

 }

@@ -226,6 +245,10 @@ BuildFvHob (
   EFI_HOB_FIRMWARE_VOLUME  *Hob;

 

   Hob = CreateHob (EFI_HOB_TYPE_FV, sizeof (EFI_HOB_FIRMWARE_VOLUME));

+  ASSERT (Hob != NULL);

+  if (Hob == NULL) {

+    return;

+  }

 

   Hob->BaseAddress = BaseAddress;

   Hob->Length      = Length;

@@ -255,6 +278,10 @@ BuildFv2Hob (
   EFI_HOB_FIRMWARE_VOLUME2  *Hob;

 

   Hob = CreateHob (EFI_HOB_TYPE_FV2, sizeof (EFI_HOB_FIRMWARE_VOLUME2));

+  ASSERT (Hob != NULL);

+  if (Hob == NULL) {

+    return;

+  }

 

   Hob->BaseAddress = BaseAddress;

   Hob->Length      = Length;

@@ -282,6 +309,10 @@ BuildCpuHob (
   EFI_HOB_CPU  *Hob;

 

   Hob = CreateHob (EFI_HOB_TYPE_CPU, sizeof (EFI_HOB_CPU));

+  ASSERT (Hob != NULL);

+  if (Hob == NULL) {

+    return;

+  }

 

   Hob->SizeOfMemorySpace = SizeOfMemorySpace;

   Hob->SizeOfIoSpace     = SizeOfIoSpace;

@@ -319,6 +350,10 @@ BuildMemoryAllocationHob (
     );

 

   Hob = CreateHob (EFI_HOB_TYPE_MEMORY_ALLOCATION, sizeof (EFI_HOB_MEMORY_ALLOCATION));

+  ASSERT (Hob != NULL);

+  if (Hob == NULL) {

+    return;

+  }

 

   ZeroMem (&(Hob->AllocDescriptor.Name), sizeof (EFI_GUID));

   Hob->AllocDescriptor.MemoryBaseAddress = BaseAddress;