From: <wen.yang99@zte.com.cn>
To: Markus.Elfring@web.de
Cc: wang.yi59@zte.com.cn, alsa-devel@alsa-project.org,
xue.zhihong@zte.com.cn, lgirdwood@gmail.com, sbkim73@samsung.com,
tiwai@suse.com, kernel-janitors@vger.kernel.org,
linux-kernel@vger.kernel.org, krzk@kernel.org,
broonie@kernel.org, s.nawrocki@samsung.com,
cheng.shengyu@zte.com.cn
Subject: Re: [2/2] ASoC: samsung: odroid: fix a double-free issue for cpu_dai
Date: Mon, 15 Jul 2019 09:49:13 +0800 (CST) [thread overview]
Message-ID: <201907150949139435825@zte.com.cn> (raw)
In-Reply-To: <4545ce50-493c-8faa-fdcd-5aee3ca30792@web.de>
> > The cpu_dai variable is still being used after the of_node_put() call,
>
> Such an implementation detail is questionable.
> https://wiki.sei.cmu.edu/confluence/display/c/MEM30-C.+Do+not+access+freed+memory
>
>
> > which may result in double-free:
>
> This consequence is also undesirable.
> https://cwe.mitre.org/data/definitions/415.html
>
>
> Now I wonder if two update steps are really appropriate as a fix
> instead of using a single update step for the desired correction
> in this software module.
> Should a commit (including previous ones) usually be correct by itself?
Thanks.
These two updates fix two different bugs.
One of them is the use-after-free issue introduced by bc3cf17b575a:
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=bc3cf17b575a7a97b4af7ddcf86133175da7a582
- ret = snd_soc_of_get_dai_link_codecs(dev, codec, link);
+ cpu_dai = of_parse_phandle(cpu, "sound-dai", 0);
+ of_node_put(cpu);
+ of_node_put(codec);
+
+ ret = snd_soc_of_get_dai_link_codecs(dev, codec, codec_link);
if (ret < 0)
goto err_put_codec_n;
and the other is the double-free issue introduced by d832d2b246c5:
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/sound/soc/samsung/odroid.c?id=d832d2b246c516eacb2d0ba53ec17ed59c3cd62b#n318
and n303, n308.
So we sent two patches to fix them separately.
--
Regards,
Wen
next prev parent reply other threads:[~2019-07-15 1:49 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-13 3:46 [PATCH 0/2] ASoC: samsung: odroid: fix err handling of odroid_audio_probe Wen Yang
2019-07-13 3:46 ` [PATCH 1/2] ASoC: samsung: odroid: fix an use-after-free issue for codec Wen Yang
2019-07-14 8:47 ` Markus Elfring
2019-07-14 10:55 ` [1/2] " Markus Elfring
2019-07-16 9:06 ` [PATCH 1/2] " Krzysztof Kozlowski
2019-07-16 18:18 ` Applied "ASoC: samsung: odroid: fix an use-after-free issue for codec" to the asoc tree Mark Brown
2019-07-13 3:46 ` [PATCH 2/2] ASoC: samsung: odroid: fix a double-free issue for cpu_dai Wen Yang
2019-07-14 12:47 ` [2/2] " Markus Elfring
2019-07-15 1:49 ` wen.yang99 [this message]
2019-07-15 6:40 ` [alsa-devel] " Markus Elfring
2019-07-16 9:06 ` [PATCH 2/2] " Krzysztof Kozlowski
2019-07-16 18:18 ` Applied "ASoC: samsung: odroid: fix a double-free issue for cpu_dai" to the asoc tree Mark Brown
2019-07-14 10:07 ` [PATCH 0/2] ASoC: samsung: odroid: fix err handling of odroid_audio_probe Markus Elfring
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