lkml.org 
[lkml]   [2019]   [Jul]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] ALSA: i2c: ak4xxx-adda: Fix a possible null pointer dereference in build_adc_controls()
From
Date


On 2019/7/25 23:52, Takashi Iwai wrote:
> On Thu, 25 Jul 2019 10:27:33 +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>
>> ---
>> sound/i2c/other/ak4xxx-adda.c | 6 ++++--
>> 1 file changed, 4 insertions(+), 2 deletions(-)
>>
>> diff --git a/sound/i2c/other/ak4xxx-adda.c b/sound/i2c/other/ak4xxx-adda.c
>> index 5f59316f982a..9a891470e84a 100644
>> --- a/sound/i2c/other/ak4xxx-adda.c
>> +++ b/sound/i2c/other/ak4xxx-adda.c
>> @@ -775,11 +775,13 @@ 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;
> The code change itself looks good, but please follow the standard
> coding style. In short: please run checkpatch.pl, fix errors (some
> warnings may be ignored) and resubmit.

Okay, thanks for the advice.
I will send a v2 patch.


Best wishes,
Jia-Ju Bai

\
 
 \ /
  Last update: 2019-07-26 04:06    [W:0.240 / U:0.040 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site