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 baijiaju1990@gmail.com --- v2: * Fix the errors reported by checkpatch.pl. Thank Takashi for helpful advice.

--- 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 5f59316f982a..b03e6d1be656 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;