Re: [edk2-devel] [PATCH 1/1] MdeModulePkg/Bus/Pci/EhciDxe: Fix FORWARD_NULL Coverity issues

["Wu, Hao A" <hao.a.wu@intel.com>]

Merged via:
PR - https://github.com/tianocore/edk2/pull/4648
Commit - https://github.com/tianocore/edk2/commit/dd49d448b0815c65847241a3faa957e3b4605001

Best Regards,
Hao Wu

> -----Original Message-----
> From: devel@edk2.groups.io <devel@edk2.groups.io> On Behalf Of Wu, Hao A
> Sent: Wednesday, July 12, 2023 12:49 PM
> To: Ranbir Singh <rsingh@ventanamicro.com>; devel@edk2.groups.io
> Cc: Ni, Ray <ray.ni@intel.com>
> Subject: Re: [edk2-devel] [PATCH 1/1] MdeModulePkg/Bus/Pci/EhciDxe: Fix
> FORWARD_NULL Coverity issues
> 
> Reviewed-by: Hao A Wu <hao.a.wu@intel.com>
> 
> Best Regards,
> Hao Wu
> 
> > -----Original Message-----
> > From: Ranbir Singh <rsingh@ventanamicro.com>
> > Sent: Monday, July 3, 2023 7:44 PM
> > To: devel@edk2.groups.io; rsingh@ventanamicro.com
> > Cc: Wu, Hao A <hao.a.wu@intel.com>; Ni, Ray <ray.ni@intel.com>
> > Subject: [PATCH 1/1] MdeModulePkg/Bus/Pci/EhciDxe: Fix FORWARD_NULL
> > Coverity issues
> >
> > From: Ranbir Singh <Ranbir.Singh3@Dell.com>
> >
> > The function UsbHcGetPciAddressForHostMem has
> >
> >     ASSERT ((Block != NULL));
> >
> > and the UsbHcFreeMem has
> >
> >     ASSERT (Block != NULL);
> >
> > statement after for loop, but these are applicable only in DEBUG mode.
> > In RELEASE mode, if for whatever reasons there is no match inside the
> > 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.
> >
> > Cc: Hao A Wu <hao.a.wu@intel.com>
> > Cc: Ray Ni <ray.ni@intel.com>
> > REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4210
> > Signed-off-by: Ranbir Singh <Ranbir.Singh3@Dell.com>
> > Signed-off-by: Ranbir Singh <rsingh@ventanamicro.com>
> > ---
> >  MdeModulePkg/Bus/Pci/EhciDxe/UsbHcMem.c | 9 +++++++++
> >  1 file changed, 9 insertions(+)
> >
> > diff --git a/MdeModulePkg/Bus/Pci/EhciDxe/UsbHcMem.c
> > b/MdeModulePkg/Bus/Pci/EhciDxe/UsbHcMem.c
> > index 0a3ceb9f711a..79575b6f6304 100644
> > --- a/MdeModulePkg/Bus/Pci/EhciDxe/UsbHcMem.c
> > +++ b/MdeModulePkg/Bus/Pci/EhciDxe/UsbHcMem.c
> > @@ -250,6 +250,11 @@ UsbHcGetPciAddressForHostMem (
> >    }
> >
> >
> >
> >    ASSERT ((Block != NULL));
> >
> > +
> >
> > +  if (Block == NULL) {
> >
> > +    return 0;
> >
> > +  }
> >
> > +
> >
> >    //
> >
> >    // calculate the pci memory address for host memory address.
> >
> >    //
> >
> > @@ -536,6 +541,10 @@ UsbHcFreeMem (
> >    //
> >
> >    ASSERT (Block != NULL);
> >
> >
> >
> > +  if (Block == NULL) {
> >
> > +    return;
> >
> > +  }
> >
> > +
> >
> >    //
> >
> >    // Release the current memory block if it is empty and not the head
> >
> >    //
> >
> > --
> > 2.34.1
> 
> 
> 
> 
>