Re: [PATCH v3 3/9] misc: fastrpc: Fix memory corruption in DSP capabilities

[Srinivas Kandagatla <srinivas.kandagatla@linaro.org>]

On 30/05/2024 11:20, Ekansh Gupta wrote:
> DSP capabilities request is sending bad size to utilities skel
What you exactly mean by this?

Curretly driver is sending 1024 bytes of buffer, why is DSP not happy 
with this size?

> call which is resulting in memory corruption. Pass proper size
What does proper size mean?
> to avoid the corruption.
> 
> Fixes: 6c16fd8bdd40 ("misc: fastrpc: Add support to get DSP capabilities")
> Cc: stable <stable@kernel.org>
> Signed-off-by: Ekansh Gupta <quic_ekangupt@quicinc.com>
> ---
>   drivers/misc/fastrpc.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
> index 61389795f498..3e1ab58038ed 100644
> --- a/drivers/misc/fastrpc.c
> +++ b/drivers/misc/fastrpc.c
> @@ -1695,6 +1695,7 @@ static int fastrpc_get_info_from_dsp(struct fastrpc_user *fl, uint32_t *dsp_attr
>   
>   	/* Capability filled in userspace */
>   	dsp_attr_buf[0] = 0;
> +	dsp_attr_buf_len -= 1;

is DSP expecting 255 *4 bytes instead of 256 *4?

--srini

>   
>   	args[0].ptr = (u64)(uintptr_t)&dsp_attr_buf_len;
>   	args[0].length = sizeof(dsp_attr_buf_len);