Re: [PATCH] PCI: mobiveil: integer overflow in IB_WIN_SIZE

From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
To: Subrahmanya Lingappa <l.subrahmanya@mobiveil.co.in>
Cc: Dan Carpenter <dan.carpenter@oracle.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	linux-pci@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] PCI: mobiveil: integer overflow in IB_WIN_SIZE
Date: Thu, 26 Jul 2018 09:46:14 +0000	[thread overview]
Message-ID: <20180726094614.GA32422@e107981-ln.cambridge.arm.com> (raw)
In-Reply-To: <CAFZiPx3AoBJk5pN0sKDQnyA_DF8R9tiuBhRfCwiGpy62EmPEhQ@mail.gmail.com>

On Mon, Jul 16, 2018 at 12:10:46PM +0530, Subrahmanya Lingappa wrote:
> Lorenzo,
> 
> looks like I missed it during the review process;
> I'll submit the Kconfig and makefile as soon as possible.

Hi Subrahmanya,

Will you have time to submit a patch soon ? I would like to queue
this fix too.

Thanks,
Lorenzo

> Thanks,
> 
> On Mon, Jul 9, 2018 at 5:12 PM, Lorenzo Pieralisi
> <lorenzo.pieralisi@arm.com> wrote:
> > On Mon, Jul 09, 2018 at 03:55:00PM +0530, Subrahmanya Lingappa wrote:
> >> Hi Lorenzo,
> >>
> >> Our reference IP's hardware registers require the to support 256GB
> >> inbound window size and this driver did exactly that I believe.
> >
> > No it does not, please check what this patch does, the window size
> > is not currently configured as you wish.
> >
> > More importantly, nobody can even test it given that this driver lacks a
> > Kconfig and a Makefile entry unless I am missing something, I presume
> > they were lost in patch reviews but you ought to fix this as soon as
> > possible please since this was something I should not have missed.
> >
> >> May I ask, why do you think this size is questionable ?
> >
> > The macro is not questionable, it is buggy, the size is what you
> > tell me it should be, I agree.
> >
> > Lorenzo
> >
> >>
> >> Thanks.
> >>
> >>
> >> On Fri, Jul 6, 2018 at 4:56 PM, Lorenzo Pieralisi
> >> <lorenzo.pieralisi@arm.com> wrote:
> >> > On Thu, Jul 05, 2018 at 12:45:39PM +0300, Dan Carpenter wrote:
> >> >> IB_WIN_SIZE is larger than INT_MAX so we need to cast it to u64.
> >> >>
> >> >> Fixes: 9af6bcb11e12 ("PCI: mobiveil: Add Mobiveil PCIe Host Bridge IP driver")
> >> >> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> >> >> ---
> >> >> Untested...  Possibly the problem is that there are too many multiplies
> >> >> by * 1024.
> >> >
> >> > Hi Subrahmanya,
> >> >
> >> > I always thought that that macro value was questionable, please
> >> > can you comment on this ?
> >> >
> >> > Thanks,
> >> > Lorenzo
> >> >
> >> >> diff --git a/drivers/pci/controller/pcie-mobiveil.c b/drivers/pci/controller/pcie-mobiveil.c
> >> >> index 4d6c20e47bed..cf0aa7cee5b0 100644
> >> >> --- a/drivers/pci/controller/pcie-mobiveil.c
> >> >> +++ b/drivers/pci/controller/pcie-mobiveil.c
> >> >> @@ -107,7 +107,7 @@
> >> >>  #define CFG_WINDOW_TYPE      0
> >> >>  #define IO_WINDOW_TYPE               1
> >> >>  #define MEM_WINDOW_TYPE      2
> >> >> -#define IB_WIN_SIZE          (256 * 1024 * 1024 * 1024)
> >> >> +#define IB_WIN_SIZE          ((u64)256 * 1024 * 1024 * 1024)
> >> >>  #define MAX_PIO_WINDOWS      8
> >> >>
> >> >>  /* Parameters for the waiting for link up routine */