From: Lv Yunlong <lyl2019@mail.ustc.edu.cn> To: perex@perex.cz, tiwai@suse.com Cc: alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org, Lv Yunlong <lyl2019@mail.ustc.edu.cn> Subject: [PATCH] sound/isa/ib: Fix two use after free in snd_sb_qsound_build Date: Mon, 26 Apr 2021 07:55:41 -0700 [thread overview] Message-ID: <20210426145541.8070-1-lyl2019@mail.ustc.edu.cn> (raw) 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> --- sound/isa/sb/sb16_csp.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/sound/isa/sb/sb16_csp.c b/sound/isa/sb/sb16_csp.c index 8635a2b6b36b..4789345a8fdd 100644 --- a/sound/isa/sb/sb16_csp.c +++ b/sound/isa/sb/sb16_csp.c @@ -1045,10 +1045,14 @@ static int snd_sb_qsound_build(struct snd_sb_csp * p) spin_lock_init(&p->q_lock); - if ((err = snd_ctl_add(card, p->qsound_switch = snd_ctl_new1(&snd_sb_qsound_switch, p))) < 0) + if ((err = snd_ctl_add(card, p->qsound_switch = snd_ctl_new1(&snd_sb_qsound_switch, p))) < 0) { + p->qsound_switch = NULL; goto __error; - if ((err = snd_ctl_add(card, p->qsound_space = snd_ctl_new1(&snd_sb_qsound_space, p))) < 0) + } + if ((err = snd_ctl_add(card, p->qsound_space = snd_ctl_new1(&snd_sb_qsound_space, p))) < 0) { + p->qsound_space = NULL; goto __error; + } return 0; -- 2.25.1
WARNING: multiple messages have this Message-ID (diff)
From: Lv Yunlong <lyl2019@mail.ustc.edu.cn> To: perex@perex.cz, tiwai@suse.com Cc: alsa-devel@alsa-project.org, Lv Yunlong <lyl2019@mail.ustc.edu.cn>, linux-kernel@vger.kernel.org Subject: [PATCH] sound/isa/ib: Fix two use after free in snd_sb_qsound_build Date: Mon, 26 Apr 2021 07:55:41 -0700 [thread overview] Message-ID: <20210426145541.8070-1-lyl2019@mail.ustc.edu.cn> (raw) 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> --- sound/isa/sb/sb16_csp.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/sound/isa/sb/sb16_csp.c b/sound/isa/sb/sb16_csp.c index 8635a2b6b36b..4789345a8fdd 100644 --- a/sound/isa/sb/sb16_csp.c +++ b/sound/isa/sb/sb16_csp.c @@ -1045,10 +1045,14 @@ static int snd_sb_qsound_build(struct snd_sb_csp * p) spin_lock_init(&p->q_lock); - if ((err = snd_ctl_add(card, p->qsound_switch = snd_ctl_new1(&snd_sb_qsound_switch, p))) < 0) + if ((err = snd_ctl_add(card, p->qsound_switch = snd_ctl_new1(&snd_sb_qsound_switch, p))) < 0) { + p->qsound_switch = NULL; goto __error; - if ((err = snd_ctl_add(card, p->qsound_space = snd_ctl_new1(&snd_sb_qsound_space, p))) < 0) + } + if ((err = snd_ctl_add(card, p->qsound_space = snd_ctl_new1(&snd_sb_qsound_space, p))) < 0) { + p->qsound_space = NULL; goto __error; + } return 0; -- 2.25.1
next reply other threads:[~2021-04-26 14:56 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-04-26 14:55 Lv Yunlong [this message] 2021-04-26 14:55 ` [PATCH] sound/isa/ib: Fix two use after free in snd_sb_qsound_build Lv Yunlong 2021-04-26 16:01 ` Takashi Iwai 2021-04-26 16:01 ` Takashi Iwai
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