[alsa-devel] [patch] sound: sequencer: cap array index in seq_chn_common_event()

[Takashi Iwai]

At Fri, 15 Mar 2013 09:14:22 +0300,
Dan Carpenter wrote:
> 
> "chn" here is a number between 0 and 255, but ->chn_info[] only has
> 16 elements so there is a potential write beyond the end of the
> array.
> 
> If the seq_mode isn't SEQ_2 then we let the individual drivers
> (either opl3.c or midi_synth.c) handle it.  Those functions all
> do a bounds check on "chn" so I haven't changed anything here.
> The opl3.c driver has up to 18 channels and not 16.
> 
> Signed-off-by: Dan Carpenter <dan.carpenter at oracle.com>

Thanks, applied now.


Takashi

> ---
> Static checker stuff.
> 
> diff --git a/sound/oss/sequencer.c b/sound/oss/sequencer.c
> index 30bcfe4..4ff60a6 100644
> --- a/sound/oss/sequencer.c
> +++ b/sound/oss/sequencer.c
> @@ -545,6 +545,9 @@ static void seq_chn_common_event(unsigned char *event_rec)
>  		case MIDI_PGM_CHANGE:
>  			if (seq_mode == SEQ_2)
>  			{
> +				if (chn > 15)
> +					break;
> +
>  				synth_devs[dev]->chn_info[chn].pgm_num = p1;
>  				if ((int) dev >= num_synths)
>  					synth_devs[dev]->set_instr(dev, chn, p1);
> @@ -596,6 +599,9 @@ static void seq_chn_common_event(unsigned char *event_rec)
>  		case MIDI_PITCH_BEND:
>  			if (seq_mode == SEQ_2)
>  			{
> +				if (chn > 15)
> +					break;
> +
>  				synth_devs[dev]->chn_info[chn].bender_value = w14;
>  
>  				if ((int) dev < num_synths)
>