commit 8aa0a07ff92ee78451ad06f297dcbf75afcc967f
author Scott Mertz <scott@cyngn.com> Tue Nov 03 12:41:51 2015 -0800
committer Jackeagle <jackeagle102gmail.com> Sun Nov 13 23:57:31 2016 +0530
tree 5b0d2021aa9784b9dfe18605c8067513200c2d9b
parent 2574b660271dad2894717ba375901065d7f0c748

tinyalsa: verify mixer control values

Many kernels don't have proper range checking on
ALSA controls, which can lead to a kernel panic.
Let's cut it off here.

Change-Id: If3b51634f550611d1605d7203d63aca5e683e0aa

mixer.c

diff --git a/mixer.c b/mixer.c
index c4e6765..9e7eec0 100644
--- a/mixer.c
+++ b/mixer.c
@@ -419,10 +419,15 @@
         break;
 
     case SNDRV_CTL_ELEM_TYPE_INTEGER:
+        if (value > mixer_ctl_get_range_max(ctl) ||
+            value < mixer_ctl_get_range_min(ctl))
+            return -EINVAL;
         ev.value.integer.value[id] = value;
         break;
 
     case SNDRV_CTL_ELEM_TYPE_ENUMERATED:
+        if (value < 0 || value >= mixer_ctl_get_num_enums(ctl))
+            return -EINVAL;
         ev.value.enumerated.item[id] = value;
         break;