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SubjectRe: [PATCH] goku_udc: Add check for NULL in goku_irq
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03.02.2023 13:45, Greg Kroah-Hartman пишет:
> On Fri, Feb 03, 2023 at 01:18:28PM +0300, Anastasia Belova wrote:
>> Before dereferencing dev->driver check it for NULL.
>>
>> If an interrupt handler is called after assigning
>> NULL to dev->driver, but before resetting dev->int_enable,
>> NULL-pointer will be dereferenced.
>>
>> Found by Linux Verification Center (linuxtesting.org) with SVACE.
>>
>> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
>> Signed-off-by: Anastasia Belova <abelova@astralinux.ru>
>> ---
>> drivers/usb/gadget/udc/goku_udc.c | 5 +++--
>> 1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/usb/gadget/udc/goku_udc.c b/drivers/usb/gadget/udc/goku_udc.c
>> index bdc56b24b5c9..896bba8b47f1 100644
>> --- a/drivers/usb/gadget/udc/goku_udc.c
>> +++ b/drivers/usb/gadget/udc/goku_udc.c
>> @@ -1616,8 +1616,9 @@ static irqreturn_t goku_irq(int irq, void *_dev)
>> pm_next:
>> if (stat & INT_USBRESET) { /* hub reset done */
>> ACK(INT_USBRESET);
>> - INFO(dev, "USB reset done, gadget %s\n",
>> - dev->driver->driver.name);
>> + if (dev->driver)
>> + INFO(dev, "USB reset done, gadget %s\n",
>> + dev->driver->driver.name);
> How can this ever happen? Can you trigger this somehow? If not, I
> don't think this is going to be possible (also what's up with printk
> from an irq handler???)

Unfortunately, I can't find the way to trigger this at the moment.

What about printk, should trace_printk be used instead?

>
> Odds are, no one actually has this hardware anymore, right?

Despite of this, such vulnerability should be fixed because

there is a possibility to exploit it.

> thanks,
>
> greg k-h

Best regards,

Anastasia Belova

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