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Commit dfc2c4a3 authored by Jia-Ju Bai's avatar Jia-Ju Bai Committed by Greg Kroah-Hartman
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ALSA: i2c: ak4xxx-adda: Fix a possible null pointer dereference in build_adc_controls() 



[ 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: default avatarJia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 19e59e3f

sound/i2c/other/ak4xxx-adda.c

+4 −3
Original line number Diff line number Diff line
@@ -789,11 +789,12 @@ 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;