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

diff --git a/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c
index 2c456a376aded18ac3a0a63013747561ccfc4f9d..c61cb9cedbcd283c22625cac53367606fb0fc18a 100644 (file)
--- 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 */