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

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@mail.ustc.edu.cn

Thanks, applied now.

Takashi