Re: [PATCH] sound/isa/ib: Fix two use after free in snd_sb_qsound_build

From: Takashi Iwai
Date: Mon Apr 26 2021 - 12:01:29 EST

On Mon, 26 Apr 2021 16:55:41 +0200,
Lv Yunlong wrote:
> In snd_sb_qsound_build, snd_ctl_add(..,p->qsound_switch...) and
> snd_ctl_add(..,p->qsound_space..) are called. But the second
> arguments of snd_ctl_add() could be freed via snd_ctl_add_replace()
> ->snd_ctl_free_one(). After the error code is returned,
> snd_sb_qsound_destroy(p) is called in __error branch.
> But in snd_sb_qsound_destroy(), the freed p->qsound_switch and
> p->qsound_space are still used by snd_ctl_remove().
> My patch set p->qsound_switch and p->qsound_space to NULL if
> snd_ctl_add() failed to avoid the uaf bugs. But these codes need
> to further be improved with the code style.
> Signed-off-by: Lv Yunlong <lyl2019@xxxxxxxxxxxxxxxx>

Thanks, applied now.