[lvc-project] [PATCH] comedi: drivers: ni_tio: Fix arithmetic expression overflow

[Ian Abbott]

On 2024-01-18 14:37, David Laight wrote:
>> -----Original Message-----
>> From: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
>> Sent: 18 January 2024 14:14
>> To: Denis Arefev <arefev at swemel.ru>
>> Cc: Ian Abbott <abbotti at mev.co.uk>; H Hartley Sweeten <hsweeten at visionengravers.com>; linux-
>> kernel at vger.kernel.org; lvc-project at linuxtesting.org; stable at vger.kernel.org
>> Subject: Re: [PATCH] comedi: drivers: ni_tio: Fix arithmetic expression overflow
>>
>> On Thu, Jan 18, 2024 at 03:37:47PM +0300, Denis Arefev wrote:
>>> The value of an arithmetic expression period_ns * 1000 is subject
>>> to overflow due to a failure to cast operands to a larger data
>>> type before performing arithmetic
>>>
>>> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>>>
>>> Fixes: 3e90b1c7ebe9 ("staging: comedi: ni_tio: tidy up ni_tio_set_clock_src() and helpers")
>>> Cc: <stable at vger.kernel.org> # v5.15+
>>> Reviewed-by: Ian Abbott <abbotti at mev.co.uk>
>>> Signed-off-by: Denis Arefev <arefev at swemel.ru>
>>> Signed-off-by: Ian Abbott <abbotti at mev.co.uk>
>>> ---
>>>   drivers/comedi/drivers/ni_tio.c | 2 +-
>>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/comedi/drivers/ni_tio.c b/drivers/comedi/drivers/ni_tio.c
>>> index da6826d77e60..acc914903c70 100644
>>> --- a/drivers/comedi/drivers/ni_tio.c
>>> +++ b/drivers/comedi/drivers/ni_tio.c
>>> @@ -800,7 +800,7 @@ static int ni_tio_set_clock_src(struct ni_gpct *counter,
>>>   				GI_PRESCALE_X2(counter_dev->variant) |
>>>   				GI_PRESCALE_X8(counter_dev->variant), bits);
>>>   	}
>>> -	counter->clock_period_ps = period_ns * 1000;
>>> +	counter->clock_period_ps = period_ns * 1000UL;
> 
> What about 32bit systems...

Oh, good point.  It should be 1000ULL.

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