ALSA: sb: Fix potential double-free of CSP mixer elements
[ 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>
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committed by
Greg Kroah-Hartman

parent
52d242f2bf
commit
0e54f8ee6b
@@ -1072,10 +1072,14 @@ static void snd_sb_qsound_destroy(struct snd_sb_csp * p)
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card = p->chip->card;
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card = p->chip->card;
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down_write(&card->controls_rwsem);
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down_write(&card->controls_rwsem);
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if (p->qsound_switch)
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if (p->qsound_switch) {
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snd_ctl_remove(card, p->qsound_switch);
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snd_ctl_remove(card, p->qsound_switch);
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if (p->qsound_space)
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p->qsound_switch = NULL;
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}
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if (p->qsound_space) {
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snd_ctl_remove(card, p->qsound_space);
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snd_ctl_remove(card, p->qsound_space);
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p->qsound_space = NULL;
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}
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up_write(&card->controls_rwsem);
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up_write(&card->controls_rwsem);
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/* cancel pending transfer of QSound parameters */
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/* cancel pending transfer of QSound parameters */
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