sound/oss/opl3: validate voice and channel indexes

User-controllable indexes for voice and channel values may cause reading and writing beyond the bounds of their respective arrays, leading to potentially exploitable memory corruption. Validate these indexes.

Signed-off-by Dan Rosenberg <[email protected]>

Cc [email protected]

---
 sound/oss/opl3.c |   15 +++++++++++++--
 1 files changed, 13 insertions(+), 2 deletions(-)

sound/oss/opl3.c +13 -2

index 938c48c..e9d443e 100644
@@ -849,6 +849,10 @@ static int opl3_load_patch(int dev, int format, const char __user *addr,
 
 static void opl3_panning(int dev, int voice, int value)
 {
+
+	if (voice < 0 || voice >= devc->nr_voice)
+		return;
+
 	devc->voc[voice].panning = value;
 }
 

@@ -1066,8 +1070,15 @@ static int opl3_alloc_voice(int dev, int chn, int note, struct voice_alloc_info
 
 static void opl3_setup_voice(int dev, int voice, int chn)
 {
-	struct channel_info *info =
-	&synth_devs[dev]->chn_info[chn];
+	struct channel_info *info;
+
+	if (voice < 0 || voice >= devc->nr_voice)
+		return;
+
+	if (chn < 0 || chn > 15)
+		return;
+
+	info = &synth_devs[dev]->chn_info[chn];
 
 	opl3_set_instr(dev, voice, info->pgm_num);