2009-12-15 13:49:54

by Alexander Strakh

Subject: BUG null dereference in driver ./drivers/net/3c507.c

KERNEL_VERSION: 2.6.32
SUBJECT: null dereference aftre check
DESCRIBE:
In driver drivers/net/3c507.c in function Iirqreturn_t el16_interrupt:

1. If in line 555 dev = NULL then we goto line 556
2. In line 556 we have null dereference because pr_err called with dev->name
in third parameter.

555 if (dev == NULL) {
556 pr_err("%s: net_interrupt(): irq %d for unknown device.
\n",
557 dev->name, irq);
558 return IRQ_NONE;
559 }

Found by Linux Device Drivers Verification Project (Svace Detector)

2009-12-15 14:16:22

by Bartlomiej Zolnierkiewicz

Subject: Re: BUG null dereference in driver ./drivers/net/3c507.c

Hi,

On Tuesday 15 December 2009 06:55:08 pm Alexander Strakh wrote:
> KERNEL_VERSION: 2.6.32
> SUBJECT: null dereference aftre check
> DESCRIBE:
> In driver drivers/net/3c507.c in function Iirqreturn_t el16_interrupt:
>
> 1. If in line 555 dev = NULL then we goto line 556
> 2. In line 556 we have null dereference because pr_err called with dev->name
> in third parameter.
>
> 555 if (dev == NULL) {
> 556 pr_err("%s: net_interrupt(): irq %d for unknown device.
> \n",
> 557 dev->name, irq);
> 558 return IRQ_NONE;
> 559 }

There is no NULL dereference bug there possible since 'dev' will never be
actually NULL in el16_interrupt() (because of the way IRQ kernel subsystem
and 3c507 network driver are designed/work).

IOW it is just a bogus NULL pointer check, though it still would be nice
to have the issue fixed. Care to send a patch removing it?

--
Bartlomiej Zolnierkiewicz