| From 31a2a8eddfdea0d4d4d9246f3fa3186500f20672 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Tue, 8 Jun 2021 16:04:37 +0200 |
| Subject: ALSA: sb: Fix potential double-free of CSP mixer elements |
| |
| From: Takashi Iwai <tiwai@suse.de> |
| |
| [ Upstream commit c305366a37441c2ac90b08711cb6f032b43672f2 ] |
| |
| snd_sb_qsound_destroy() contains the calls of removing the previously |
| created mixer controls, but it doesn't clear the pointers. As |
| snd_sb_qsound_destroy() itself may be repeatedly called via ioctl, |
| this could lead to double-free potentially. |
| |
| Fix it by clearing the struct fields properly afterwards. |
| |
| Link: https://lore.kernel.org/r/20210608140540.17885-4-tiwai@suse.de |
| Signed-off-by: Takashi Iwai <tiwai@suse.de> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| 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 4789345a8fdd..c98ccd421a2e 100644 |
| --- a/sound/isa/sb/sb16_csp.c |
| +++ b/sound/isa/sb/sb16_csp.c |
| @@ -1072,10 +1072,14 @@ static void snd_sb_qsound_destroy(struct snd_sb_csp * p) |
| card = p->chip->card; |
| |
| down_write(&card->controls_rwsem); |
| - if (p->qsound_switch) |
| + if (p->qsound_switch) { |
| snd_ctl_remove(card, p->qsound_switch); |
| - if (p->qsound_space) |
| + p->qsound_switch = NULL; |
| + } |
| + if (p->qsound_space) { |
| snd_ctl_remove(card, p->qsound_space); |
| + p->qsound_space = NULL; |
| + } |
| up_write(&card->controls_rwsem); |
| |
| /* cancel pending transfer of QSound parameters */ |
| -- |
| 2.30.2 |
| |
