Re: [PATCH 1/2] ASoC: SOF: sof-client-probes: fix error codes in sof_probes_compr_copy()

Péter Ujfalusi
2022-07-06T10:43:00Z

On 06/07/2022 13:31, Dan Carpenter wrote:
> On Wed, Jul 06, 2022 at 01:21:59PM +0300, Dan Carpenter wrote:
>> On Wed, Jul 06, 2022 at 12:05:37PM +0300, Péter Ujfalusi wrote:
>>>
>>>
>>> On 06/07/2022 10:23, Dan Carpenter wrote:
>>>> This function tries to return the number of bytes that it was able to
>>>> copy to the user. However, because there are multiple calls to
>>>> copy_to_user() in a row that means the bytes are not necessarily
>>>> consecutive so it's not useful. Just return -EFAULT instead.
>>>
>>> The function is copying data from a circular buffer to a use buffer.
>>> The single copy_to_user() is used when we don't have wrapping, the
>>> 'double' copy_to_user() is when we wrap, so first copy is from the end
>>> of the buffer then we copy the data from the start of the buffer to get
>>> all data.
>>
>> Ok. But the bugs in the original code are real. I will resend.
>
> Actually that's not true. The bugs in the original code are something
> that only affect users who deserve it? I might not resend. A fix would
> look something like below?
>
> regards,
> dan carpenter
>
> diff --git a/sound/soc/sof/sof-client-probes.c b/sound/soc/sof/sof-client-probes.c
> index 1f1ea93a7fbf..32fa3186c295 100644
> --- a/sound/soc/sof/sof-client-probes.c
> +++ b/sound/soc/sof/sof-client-probes.c
> @@ -398,9 +398,14 @@ static int sof_probes_compr_copy(struct snd_soc_component *component,
> ret = copy_to_user(buf, ptr, count);
> } else {
> ret = copy_to_user(buf, ptr, n);
> - ret += copy_to_user(buf + n, rtd->dma_area, count - n);
> + if (ret) {
> + ret += count - n;
> + goto done;
> + }
> + ret = copy_to_user(buf + n, rtd->dma_area, count - n);

I think this should work, can you please resend it?

> }
>
> +done:
> if (ret)
> return count - ret;
> return count;

--
Péter