[PATCH 3.16.y-ckt 095/142] ALSA: hdspm: Fix zero-division

[Luis Henriques]

3.16.7-ckt26 -stable review patch.  If anyone has any objections, please let me know.

---8<------------------------------------------------------------

From: Takashi Iwai <tiwai@xxxxxxx>

commit c1099c3294c2344110085a38c50e478a5992b368 upstream.

HDSPM driver contains a code issuing zero-division potentially in
system sample rate ctl code.  This patch fixes it by not processing
a zero or invalid rate value as a divisor, as well as excluding the
invalid value to be passed via the given ctl element.

Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
 sound/pci/rme9652/hdspm.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/sound/pci/rme9652/hdspm.c b/sound/pci/rme9652/hdspm.c
index 004fd3260048..811d3c1eb338 100644
--- a/sound/pci/rme9652/hdspm.c
+++ b/sound/pci/rme9652/hdspm.c
@@ -1602,6 +1602,9 @@ static void hdspm_set_dds_value(struct hdspm *hdspm, int rate)
 {
 	u64 n;
 
+	if (snd_BUG_ON(rate <= 0))
+		return;
+
 	if (rate >= 112000)
 		rate /= 4;
 	else if (rate >= 56000)
@@ -2220,6 +2223,8 @@ static int hdspm_get_system_sample_rate(struct hdspm *hdspm)
 		} else {
 			/* slave mode, return external sample rate */
 			rate = hdspm_external_sample_rate(hdspm);
+			if (!rate)
+				rate = hdspm->system_sample_rate;
 		}
 	}
 
@@ -2265,7 +2270,10 @@ static int snd_hdspm_put_system_sample_rate(struct snd_kcontrol *kcontrol,
 					    ucontrol)
 {
 	struct hdspm *hdspm = snd_kcontrol_chip(kcontrol);
+	int rate = ucontrol->value.integer.value[0];
 
+	if (rate < 27000 || rate > 207000)
+		return -EINVAL;
 	hdspm_set_dds_value(hdspm, ucontrol->value.integer.value[0]);
 	return 0;
 }