[PATCH 3.19.y-ckt 31/70] ALSA: hdspm: Fix zero-division

[Kamal Mostafa]

v3.19.8-ckt17 -stable review patch.  If anyone has any objections, please let 
me know.

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

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: Kamal Mostafa <ka...@canonical.com>
---
 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 5dadc78..5c14afa1 100644
--- a/sound/pci/rme9652/hdspm.c
+++ b/sound/pci/rme9652/hdspm.c
@@ -1601,6 +1601,9 @@ 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)
@@ -2219,6 +2222,8 @@ 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;
                }
        }
 
@@ -2264,7 +2269,10 @@ 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;
 }
-- 
2.7.0