sound: sequencer: cap array index in seq_chn_common_event()

"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@oracle.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/oss/sequencer.c b/sound/oss/sequencer.c
index 30bcfe470f8310fa7fa72cc1ddcf7ab4ba6a794c..4ff60a6427d9d8d3ea7cf095bc2766f2d49955fc 100644 (file)
--- 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)