[PATCH] MdeModulePkg/Bus/Pci/PciHostBridgeDxe: Fix various Coverity issues

[PATCH] MdeModulePkg/Bus/Pci/PciHostBridgeDxe: Fix various Coverity issues

[Ranbir Singh]

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The function NotifyPhase has a check

ASSERT (Index < TypeMax);

but this comes into play only in DEBUG mode. In Release mode, there is
no handling if the Index value is within array limits or not. If for
whatever reasons, the Index does not get re-assigned to Index2 at line
137, then it remains at TypeMax as assigned earlier at line 929. This
poses array overrun risk at lines 942 and 943. It is better to deploy
a safety check before line 942 as

if (Index >= TypeMax) {
continue;
}

The function SubmitResources has a switch-case code in which the
case ACPI_ADDRESS_SPACE_TYPE_MEM: which falls through to
case ACPI_ADDRESS_SPACE_TYPE_IO: if there is no scenario of
return EFI_INVALID_PARAMETER;

While this may be intentional, it is not evident to any general code
reader as well as any static analyzer tool. Just adding

// No break; here as this is an intentional fallthrough.

as comment in between makes any reader as well as Coverity happy.

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4212
Signed-off-by: Ranbir Singh <Ranbir.Singh3@Dell.com>
---
MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridge.c | 9 +++++++++
1 file changed, 9 insertions(+)

diff --git a/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridge.c b/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridge.c
index b20bcd310a..83f1ad450f 100644
--- a/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridge.c
+++ b/MdeModulePkg/Bus/Pci/PciHostBridgeDxe/PciHostBridge.c
@@ -939,6 +939,11 @@ NotifyPhase (
}

ASSERT (Index < TypeMax);
+
+            if (Index >= TypeMax) {
+                continue;
+            }
+
ResNodeHandled[Index] = TRUE;
Alignment             = RootBridge->ResAllocNode[Index].Alignment;
BitsOfAlignment       = LowBitSet64 (Alignment + 1);
@@ -1526,6 +1531,10 @@ SubmitResources (
return EFI_INVALID_PARAMETER;
}

+            //
+            // No break; here as this is an intentional fall through.
+            //
+
case ACPI_ADDRESS_SPACE_TYPE_IO:
//
// Check aligment, it should be of the form 2^n-1
--
2.36.1.windows.1

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