From dc1c1ab453b5b6011e317f08ecabb74d409dfe31 Mon Sep 17 00:00:00 2001
From: Gua Guo <[email protected]>
Date: Thu, 11 Jan 2024 13:07:50 +0800
Subject: [PATCH 09/10] EmbeddedPkg/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 <[email protected]>
Cc: Leif Lindholm <[email protected]>
Reviewed-by: Ard Biesheuvel <[email protected]>
Cc: Abner Chang <[email protected]>
Cc: John Mathew <[email protected]>
Authored-by: Gerd Hoffmann <[email protected]>
Signed-off-by: Gua Guo <[email protected]>

reference: https://github.com/tianocore/edk2/pull/5273
Signed-off-by: yexiao <[email protected]>
---
 EmbeddedPkg/Library/PrePiHobLib/Hob.c | 43 +++++++++++++++++++++++++++
 1 file changed, 43 insertions(+)

diff --git a/EmbeddedPkg/Library/PrePiHobLib/Hob.c b/EmbeddedPkg/Library/PrePiHobLib/Hob.c
index b5cc6c5d..2daf6f56 100644
--- a/EmbeddedPkg/Library/PrePiHobLib/Hob.c
+++ b/EmbeddedPkg/Library/PrePiHobLib/Hob.c
@@ -112,6 +112,13 @@ 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;
@@ -162,6 +169,9 @@ 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;
@@ -403,6 +413,10 @@ BuildModuleHob (
           ((ModuleLength & (EFI_PAGE_SIZE - 1)) == 0));
 
   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;
@@ -451,6 +465,11 @@ 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;
 }
@@ -516,6 +535,10 @@ 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;
@@ -548,6 +571,10 @@ 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;
@@ -589,6 +616,10 @@ BuildFv3Hob (
   EFI_HOB_FIRMWARE_VOLUME3  *Hob;
 
   Hob = CreateHob (EFI_HOB_TYPE_FV3, sizeof (EFI_HOB_FIRMWARE_VOLUME3));
+  ASSERT (Hob != NULL);
+  if (Hob == NULL) {
+    return;
+  }
 
   Hob->BaseAddress          = BaseAddress;
   Hob->Length               = Length;
@@ -645,6 +676,10 @@ 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;
@@ -681,6 +716,10 @@ BuildStackHob (
           ((Length & (EFI_PAGE_SIZE - 1)) == 0));
 
   Hob = CreateHob (EFI_HOB_TYPE_MEMORY_ALLOCATION, sizeof (EFI_HOB_MEMORY_ALLOCATION_STACK));
+  ASSERT (Hob != NULL);
+  if (Hob == NULL) {
+    return;
+  }
 
   CopyGuid (&(Hob->AllocDescriptor.Name), &gEfiHobMemoryAllocStackGuid);
   Hob->AllocDescriptor.MemoryBaseAddress = BaseAddress;
@@ -761,6 +800,10 @@ BuildMemoryAllocationHob (
           ((Length & (EFI_PAGE_SIZE - 1)) == 0));
 
   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;
-- 
2.33.0