[PATCH] ALSA: isa/wavefront: prevent out of bounds write in ioctl

[Takashi Iwai]

On Fri, 01 May 2020 11:40:11 +0200,
Dan Carpenter wrote:
> 
> The "header->number" comes from the ioctl and it needs to be clamped to
> prevent out of bounds writes.
> 
> Signed-off-by: Dan Carpenter <dan.carpenter at oracle.com>

Applied now.  Thanks.


Takashi

> ---
> This code predates git.
> 
>  sound/isa/wavefront/wavefront_synth.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/sound/isa/wavefront/wavefront_synth.c b/sound/isa/wavefront/wavefront_synth.c
> index c5b1d5900eed2..d6420d224d097 100644
> --- a/sound/isa/wavefront/wavefront_synth.c
> +++ b/sound/isa/wavefront/wavefront_synth.c
> @@ -1171,7 +1171,10 @@ wavefront_send_alias (snd_wavefront_t *dev, wavefront_patch_info *header)
>  				      "alias for %d\n",
>  				      header->number,
>  				      header->hdr.a.OriginalSample);
> -    
> +
> +	if (header->number >= WF_MAX_SAMPLE)
> +		return -EINVAL;
> +
>  	munge_int32 (header->number, &alias_hdr[0], 2);
>  	munge_int32 (header->hdr.a.OriginalSample, &alias_hdr[2], 2);
>  	munge_int32 (*((unsigned int *)&header->hdr.a.sampleStartOffset),
> @@ -1202,6 +1205,9 @@ wavefront_send_multisample (snd_wavefront_t *dev, wavefront_patch_info *header)
>  	int num_samples;
>  	unsigned char *msample_hdr;
>  
> +	if (header->number >= WF_MAX_SAMPLE)
> +		return -EINVAL;
> +
>  	msample_hdr = kmalloc(WF_MSAMPLE_BYTES, GFP_KERNEL);
>  	if (! msample_hdr)
>  		return -ENOMEM;
> -- 
> 2.26.2
>