When the {orig,midi}_dev equals num_midis, that's one too large already.
Signed-off-by: Roel Kluin roel.kluin@gmail.com --- In MIDIbuf_open() sound/oss/midibuf.c:166
if (num_midis > MAX_MIDI_DEV) { printk(KERN_ERR "midi: Too many midi interfaces\n"); num_midis = MAX_MIDI_DEV; }
num_midis is at most MAX_MIDI_DEV.
`git grep -n MAX_MIDI_DEV' and note that when the index equals num_midis this causes reads/writes outside array bounds for midi_devs, midi2synth, dev_conf and others (below check in patch).
sound/oss/midi_synth.c | 2 +- sound/oss/mpu401.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/sound/oss/midi_synth.c b/sound/oss/midi_synth.c index 9e45098..3bc7104 100644 --- a/sound/oss/midi_synth.c +++ b/sound/oss/midi_synth.c @@ -426,7 +426,7 @@ midi_synth_open(int dev, int mode) int err; struct midi_input_info *inc;
- if (orig_dev < 0 || orig_dev > num_midis || midi_devs[orig_dev] == NULL) + if (orig_dev < 0 || orig_dev >= num_midis || midi_devs[orig_dev] == NULL) return -ENXIO;
midi2synth[orig_dev] = dev; diff --git a/sound/oss/mpu401.c b/sound/oss/mpu401.c index 734b8f9..0af9d24 100644 --- a/sound/oss/mpu401.c +++ b/sound/oss/mpu401.c @@ -770,7 +770,7 @@ static int mpu_synth_ioctl(int dev, unsigned int cmd, void __user *arg)
midi_dev = synth_devs[dev]->midi_dev;
- if (midi_dev < 0 || midi_dev > num_midis || midi_devs[midi_dev] == NULL) + if (midi_dev < 0 || midi_dev >= num_midis || midi_devs[midi_dev] == NULL) return -ENXIO;
devc = &dev_conf[midi_dev];