[PATCH 4.4 54/74] ALSA: hdspm: Fix zero-division

[Greg Kroah-Hartman]

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

------------------

From: Takashi Iwai <ti...@suse.de>

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 <ti...@suse.de>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>

---
 sound/pci/rme9652/hdspm.c |    8 ++++++++
 1 file changed, 8 insertions(+)

--- a/sound/pci/rme9652/hdspm.c
+++ b/sound/pci/rme9652/hdspm.c
@@ -1601,6 +1601,9 @@ static void hdspm_set_dds_value(struct h
 {
        u64 n;
 
+       if (snd_BUG_ON(rate <= 0))
+               return;
+
        if (rate >= 112000)
                rate /= 4;
        else if (rate >= 56000)
@@ -2215,6 +2218,8 @@ static int hdspm_get_system_sample_rate(
                } else {
                        /* slave mode, return external sample rate */
                        rate = hdspm_external_sample_rate(hdspm);
+                       if (!rate)
+                               rate = hdspm->system_sample_rate;
                }
        }
 
@@ -2260,7 +2265,10 @@ static int snd_hdspm_put_system_sample_r
                                            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;
 }