Re: [PATCH] staging: rts5208: add check on NULL before dereference

okaya
2018-06-09T16:58:33Z

On 2018-06-09 12:38, Anton Vasilyev wrote:
> If rtsx_probe fails to allocate dev->chip, then NULL pointer
> dereference occurs at rtsx_release_resources().
>
> Patch adds checks chip on NULL before its dereference at
> rtsx_release_resources and passing with dereference inside
> rtsx_release_chip.
>
> Found by Linux Driver Verification project (linuxtesting.org).
>
> Signed-off-by: Anton Vasilyev <vasilyev@ispras.ru>
> ---
> drivers/staging/rts5208/rtsx.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/staging/rts5208/rtsx.c
> b/drivers/staging/rts5208/rtsx.c
> index 70e0b8623110..952dd0d580cf 100644
> --- a/drivers/staging/rts5208/rtsx.c
> +++ b/drivers/staging/rts5208/rtsx.c
> @@ -623,12 +623,13 @@ static void rtsx_release_resources(struct
> rtsx_dev *dev)
>

I think you should bail out if dev->chip is null rather than adding
conditiinals.

> if (dev->irq > 0)
> free_irq(dev->irq, (void *)dev);
> - if (dev->chip->msi_en)
> + if (dev->chip && dev->chip->msi_en)
> pci_disable_msi(dev->pci);
> if (dev->remap_addr)
> iounmap(dev->remap_addr);
> + if (dev->chip)
> + rtsx_release_chip(dev->chip);
>
> - rtsx_release_chip(dev->chip);
> kfree(dev->chip);
> }