| Message ID | 20190725082733.15234-1-baijiaju1990@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ALSA: i2c: ak4xxx-adda: Fix a possible null pointer dereference in build_adc_controls() | expand |
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. thanks, Takashi
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
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;
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(-)