[edk2-devel] [PATCH v1 1/2] MdeModulePkg/Bus/Pci/XhciDxe: Fix FORWARD_NULL Coverity issues

["Ranbir Singh" <rsingh@ventanamicro.com>]

From: Ranbir Singh <Ranbir.Singh3@Dell.com>

The functions UsbHcGetHostAddrForPciAddr, UsbHcGetPciAddrForHostAddr
and UsbHcFreeMem do have

    ASSERT ((Block != NULL));

statements after for loop, but these are applicable only in DEBUG mode.
In RELEASE mode, if for whatever reasons there is no match inside for
loop and the loop exits because of Block != NULL; condition, then there
is no "Block" NULL pointer check afterwards and the code proceeds to do
dereferencing "Block" which will lead to CRASH.

Hence, for safety add NULL pointer checks always.

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4221

Cc: Hao A Wu <hao.a.wu@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Co-authored-by: Veeresh Sangolli <veeresh.sangolli@dellteam.com>
Signed-off-by: Ranbir Singh <Ranbir.Singh3@Dell.com>
Signed-off-by: Ranbir Singh <rsingh@ventanamicro.com>
---
 MdeModulePkg/Bus/Pci/XhciDxe/UsbHcMem.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/MdeModulePkg/Bus/Pci/XhciDxe/UsbHcMem.c b/MdeModulePkg/Bus/Pci/XhciDxe/UsbHcMem.c
index b54187ec228e..b0654f148c4f 100644
--- a/MdeModulePkg/Bus/Pci/XhciDxe/UsbHcMem.c
+++ b/MdeModulePkg/Bus/Pci/XhciDxe/UsbHcMem.c
@@ -267,6 +267,11 @@ UsbHcGetPciAddrForHostAddr (
   }
 
   ASSERT ((Block != NULL));
+
+  if (Block == NULL) {
+    return 0;
+  }
+
   //
   // calculate the pci memory address for host memory address.
   //
@@ -322,6 +327,11 @@ UsbHcGetHostAddrForPciAddr (
   }
 
   ASSERT ((Block != NULL));
+
+  if (Block == NULL) {
+    return 0;
+  }
+
   //
   // calculate the pci memory address for host memory address.
   //
@@ -603,6 +613,10 @@ UsbHcFreeMem (
   //
   ASSERT (Block != NULL);
 
+  if (Block == NULL) {
+    return;
+  }
+
   //
   // Release the current memory block if it is empty and not the head
   //
-- 
2.34.1



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