From: Jia-Ju Bai <baijiaju1...@gmail.com>

[ Upstream commit 2127c01b7f63b06a21559f56a8c81a3c6535bd1a ]

In build_adc_controls(), there is an if statement on line 773 to check
whether ak->adc_info is NULL:
    if (! ak->adc_info ||
        ! ak->adc_info[mixer_ch].switch_name)

When ak->adc_info is NULL, it is used on line 792:
    knew.name = ak->adc_info[mixer_ch].selector_name;

Thus, a possible null-pointer dereference may occur.

To fix this bug, referring to lines 773 and 774, ak->adc_info
and ak->adc_info[mixer_ch].selector_name are checked before being used.

This bug is found by a static analysis tool STCheck written by us.

Signed-off-by: Jia-Ju Bai <baijiaju1...@gmail.com>
Signed-off-by: Takashi Iwai <ti...@suse.de>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 sound/i2c/other/ak4xxx-adda.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/sound/i2c/other/ak4xxx-adda.c b/sound/i2c/other/ak4xxx-adda.c
index 5f59316f982ae..7d15093844b92 100644
--- a/sound/i2c/other/ak4xxx-adda.c
+++ b/sound/i2c/other/ak4xxx-adda.c
@@ -775,11 +775,12 @@ static int build_adc_controls(struct snd_akm4xxx *ak)
                                return err;
 
                        memset(&knew, 0, sizeof(knew));
-                       knew.name = ak->adc_info[mixer_ch].selector_name;
-                       if (!knew.name) {
+                       if (!ak->adc_info ||
+                               !ak->adc_info[mixer_ch].selector_name) {
                                knew.name = "Capture Channel";
                                knew.index = mixer_ch + ak->idx_offset * 2;
-                       }
+                       } else
+                               knew.name = 
ak->adc_info[mixer_ch].selector_name;
 
                        knew.iface = SNDRV_CTL_ELEM_IFACE_MIXER;
                        knew.info = ak4xxx_capture_source_info;
-- 
2.20.1

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