* [PATCH v2] ALSA: i2c: ak4xxx-adda: Fix a possible null pointer dereference in build_adc_controls()
@ 2019-07-26 2:14 Jia-Ju Bai
2019-07-26 12:26 ` Takashi Iwai
0 siblings, 1 reply; 2+ messages in thread
From: Jia-Ju Bai @ 2019-07-26 2:14 UTC (permalink / raw)
To: perex, tiwai, tglx, rfontana, gregkh; +Cc: alsa-devel, linux-kernel, Jia-Ju Bai
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;
--
2.17.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH v2] ALSA: i2c: ak4xxx-adda: Fix a possible null pointer dereference in build_adc_controls()
2019-07-26 2:14 [PATCH v2] ALSA: i2c: ak4xxx-adda: Fix a possible null pointer dereference in build_adc_controls() Jia-Ju Bai
@ 2019-07-26 12:26 ` Takashi Iwai
0 siblings, 0 replies; 2+ messages in thread
From: Takashi Iwai @ 2019-07-26 12:26 UTC (permalink / raw)
To: Jia-Ju Bai; +Cc: tglx, gregkh, perex, rfontana, alsa-devel, linux-kernel
On Fri, 26 Jul 2019 04:14:42 +0200,
Jia-Ju Bai wrote:
>
> 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>
Applied, thanks.
Takashi
^ permalink raw reply [flat|nested] 2+ messages in thread
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2019-07-26 2:14 [PATCH v2] ALSA: i2c: ak4xxx-adda: Fix a possible null pointer dereference in build_adc_controls() Jia-Ju Bai
2019-07-26 12:26 ` Takashi Iwai
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