ASoC: soc-dapm: fix use after free

Coverity spotted the following possible use-after-free condition in
dapm_create_or_share_mixmux_kcontrol():

If kcontrol is NULL, and (wname_in_long_name && kcname_in_long_name)
validates to true, 'name' will be set to an allocated string, and be
freed a few lines later via the 'long_name' alias. 'name', however,
is used by dev_err() in case snd_ctl_add() fails.

Fix this by adding a jump label that frees 'long_name' at the end of
the function.

Signed-off-by: Daniel Mack <daniel@zonque.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org

1 files changed, 14 insertions, 11 deletions

diff --git a/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c
index 2c456a376ade..c61cb9cedbcd 100644
--- a/sound/soc/soc-dapm.c
+++ b/sound/soc/soc-dapm.c
@@ -592,9 +592,9 @@ static int dapm_create_or_share_mixmux_kcontrol(struct snd_soc_dapm_widget *w,
         int shared;
         struct snd_kcontrol *kcontrol;
         bool wname_in_long_name, kcname_in_long_name;
-        char *long_name;
+        char *long_name = NULL;
         const char *name;
-        int ret;
+        int ret = 0;
 
         prefix = soc_dapm_prefix(dapm);
         if (prefix)
@@ -653,15 +653,17 @@ static int dapm_create_or_share_mixmux_kcontrol(struct snd_soc_dapm_widget *w,
 
                 kcontrol = snd_soc_cnew(&w->kcontrol_news[kci], NULL, name,
                                         prefix);
-                kfree(long_name);
-                if (!kcontrol)
-                        return -ENOMEM;
+                if (!kcontrol) {
+                        ret = -ENOMEM;
+                        goto exit_free;
+                }
+
                 kcontrol->private_free = dapm_kcontrol_free;
 
                 ret = dapm_kcontrol_data_alloc(w, kcontrol);
                 if (ret) {
                         snd_ctl_free_one(kcontrol);
-                        return ret;
+                        goto exit_free;
                 }
 
                 ret = snd_ctl_add(card, kcontrol);
@@ -669,17 +671,18 @@ static int dapm_create_or_share_mixmux_kcontrol(struct snd_soc_dapm_widget *w,
                         dev_err(dapm->dev,
                                 "ASoC: failed to add widget %s dapm kcontrol %s: %d\n",
                                 w->name, name, ret);
-                        return ret;
+                        goto exit_free;
                 }
         }
 
         ret = dapm_kcontrol_add_widget(kcontrol, w);
-        if (ret)
-                return ret;
+        if (ret == 0)
+                w->kcontrols[kci] = kcontrol;
 
-        w->kcontrols[kci] = kcontrol;
+exit_free:
+        kfree(long_name);
 
-        return 0;
+        return ret;
 }
 
 /* create new dapm mixer control */