From: Takashi Iwai <tiwai@suse.de>
To: "Jia-Ju Bai" <baijiaju1990@gmail.com>
Cc: <tglx@linutronix.de>, <gregkh@linuxfoundation.org>,
<perex@perex.cz>, <rfontana@redhat.com>,
<alsa-devel@alsa-project.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] ALSA: i2c: ak4xxx-adda: Fix a possible null pointer dereference in build_adc_controls()
Date: Thu, 25 Jul 2019 17:52:03 +0200 [thread overview]
Message-ID: <s5hy30myuvw.wl-tiwai@suse.de> (raw)
In-Reply-To: <20190725082733.15234-1-baijiaju1990@gmail.com>
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
WARNING: multiple messages have this Message-ID (diff)
From: Takashi Iwai <tiwai@suse.de>
To: Jia-Ju Bai <baijiaju1990@gmail.com>
Cc: tglx@linutronix.de, gregkh@linuxfoundation.org, perex@perex.cz,
rfontana@redhat.com, alsa-devel@alsa-project.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] ALSA: i2c: ak4xxx-adda: Fix a possible null pointer dereference in build_adc_controls()
Date: Thu, 25 Jul 2019 17:52:03 +0200 [thread overview]
Message-ID: <s5hy30myuvw.wl-tiwai@suse.de> (raw)
In-Reply-To: <20190725082733.15234-1-baijiaju1990@gmail.com>
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
next prev parent reply other threads:[~2019-07-25 15:52 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-25 8:27 [PATCH] ALSA: i2c: ak4xxx-adda: Fix a possible null pointer dereference in build_adc_controls() Jia-Ju Bai
2019-07-25 15:52 ` Takashi Iwai [this message]
2019-07-25 15:52 ` Takashi Iwai
2019-07-26 2:05 ` Jia-Ju Bai
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=s5hy30myuvw.wl-tiwai@suse.de \
--to=tiwai@suse.de \
--cc=alsa-devel@alsa-project.org \
--cc=baijiaju1990@gmail.com \
--cc=gregkh@linuxfoundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=perex@perex.cz \
--cc=rfontana@redhat.com \
--cc=tglx@linutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.