DxePagingAudit: Add Function to Check Attributes Using GetRegionAcces…

…sAttributes()

Description

ValidatePageTableAttributes() is a function that validates the attributes
of the input memory region. It uses GetRegionAccessAttributes() to get
the attributes of the region and compares them to the
attributes passed in. This function will be used by each test case
to check that the page/translation table attributes match the memory
protection requirements.

- [x] Impacts functionality?
  - **Functionality** - Does the change ultimately impact how firmware functions?
  - Examples: Add a new library, publish a new PPI, update an algorithm, ...
- [ ] Impacts security?
  - **Security** - Does the change have a direct security impact on an application,
    flow, or firmware?
  - Examples: Crypto algorithm change, buffer overflow fix, parameter
    validation improvement, ...
- [ ] Breaking change?
  - **Breaking change** - Will anyone consuming this change experience a break
    in build or boot behavior?
  - Examples: Add a new library class, move a module to a different repo, call
    a function in a new library class in a pre-existing module, ...
- [ ] Includes tests?
  - **Tests** - Does the change include any explicit test code?
  - Examples: Unit tests, integration tests, robot tests, ...
- [ ] Includes documentation?
  - **Documentation** - Does the change contain explicit documentation additions
    outside direct code modifications (and comments)?
  - Examples: Update readme file, add feature readme file, link to documentation
    on an a separate Web page, ...

How This Was Tested

Tested on Q35 by running the app with the following patch.

Integration Instructions

N/A

UefiTestingPkg/AuditTests/PagingAudit/UEFI/Dxe/App/DxePagingAuditTestApp.c

@@ -568,6 +568,121 @@ GetRegionCommonAccessAttributes (
   return FoundRange ? EFI_SUCCESS : EFI_NOT_FOUND;
 }
 
+/**
+  Checks the input flat page/translation table for the input region and validates
+  the attributes match the input attributes.
+
+  @param[in]  Map                   Pointer to the PAGE_MAP struct to be parsed
+  @param[in]  Address               Start address of the region
+  @param[in]  Length                Length of the region
+  @param[in]  RequiredAttributes    The required EFI Attributes of the region
+  @param[in]  MatchAnyAttribute     If TRUE, the region must contain at least one of the
+                                    required attributes. If FALSE, the region must contain
+                                    all of the required attributes.
+  @param[in]  AllowUnmappedRegions  If TRUE, unmapped regions are excepted from the check.
+  @param[in]  LogAttributeMismatch  If TRUE, log the attribute mismatch via DEBUG().
+
+  @retval TRUE                   The region has the required attributes
+  @retval FALSE                  The region does not have the required attributes
+**/
+STATIC
+BOOLEAN
+ValidateRegionAttributes (
+  IN PAGE_MAP  *Map,
+  IN UINT64    Address,
+  IN UINT64    Length,
+  IN UINT64    RequiredAttributes,
+  IN BOOLEAN   MatchAnyAttribute,
+  IN BOOLEAN   AllowUnmappedRegions,
+  IN BOOLEAN   LogAttributeMismatch
+  )
+{
+  UINT64      RegionAttributes;
+  UINT64      CheckedLength;
+  EFI_STATUS  Status;
+  BOOLEAN     AttributesMatch;
+
+  AttributesMatch = TRUE;
+
+  do {
+    RegionAttributes = 0;
+    CheckedLength    = 0;
+    Status           = GetRegionAccessAttributes (
+                         Map,
+                         Address,
+                         Length,
+                         &RegionAttributes,
+                         &CheckedLength
+                         );
+
+    // If the region was completely or partially matched, check the returned attributes against the
+    // expected attributes
+    if ((Status == EFI_SUCCESS) || (Status == EFI_NOT_FOUND)) {
+      if (((!MatchAnyAttribute && ((RegionAttributes & RequiredAttributes) != RequiredAttributes)) ||
+           (MatchAnyAttribute && ((RegionAttributes & RequiredAttributes) == 0))))
+      {
+        if (LogAttributeMismatch) {
+          UT_LOG_ERROR (
+            "Region 0x%llx-0x%llx does not %a%a%a%a\n",
+            Address,
+            Address + CheckedLength,
+            MatchAnyAttribute ? "contain a superset of the following attribute(s): " : "match exactly the following attribute(s): ",
+            ((RequiredAttributes & EFI_MEMORY_RP) != 0) ? "EFI_MEMORY_RP " : "",
+            ((RequiredAttributes & EFI_MEMORY_RO) != 0) ? "EFI_MEMORY_RO " : "",
+            ((RequiredAttributes & EFI_MEMORY_XP) != 0) ? "EFI_MEMORY_XP " : ""
+            );
+        }
+
+        AttributesMatch = FALSE;
+      }
+    }
+    // If the region was not found, check if unmapped regions are OK
+    else if (Status == EFI_NO_MAPPING) {
+      if (!AllowUnmappedRegions) {
+        if (LogAttributeMismatch) {
+          UT_LOG_ERROR (
+            "Region 0x%llx-0x%llx is not mapped\n",
+            Address,
+            Address + CheckedLength
+            );
+        }
+
+        AttributesMatch = FALSE;
+      }
+    }
+    // If an unexpected status was returned, break out of the loop and return failure
+    else {
+      UT_LOG_INFO (
+        "Failed to get attributes for Address: 0x%llx, Length: 0x%llx. Status: %r\n",
+        Address,
+        Length,
+        Status
+        );
+      AttributesMatch = FALSE;
+      break;
+    }
+
+    if (CheckedLength == 0) {
+      UT_LOG_INFO (
+        "Unexpected error occurred when parsing the page table for 0x%llx-0x%llx!\n",
+        Address,
+        Address + Length
+        );
+
+      AttributesMatch = FALSE;
+      break;
+    }
+
+    if (EFI_ERROR (SafeUint64Add (Address, CheckedLength, &Address))) {
+      break;
+    }
+
+    Length -= CheckedLength;
+  } while (Length > 0);
+
+  return AttributesMatch;
+}
+
 // ----------------------
 //    CLEANUP FUNCTION
 // ----------------------