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authorTakashi Iwai <tiwai@suse.de>2017-05-24 10:19:45 +0200
committerMark Brown <broonie@kernel.org>2017-05-24 18:11:08 +0100
commit4efda5f2130da033aeedc5b3205569893b910de2 (patch)
tree9a55c0a2d19260fe65c2fb6c2a401bc6a951abca /sound
parent2ea659a9ef488125eb46da6eb571de5eae5c43f6 (diff)
ASoC: Fix use-after-free at card unregistration
soc_cleanup_card_resources() call snd_card_free() at the last of its procedure. This turned out to lead to a use-after-free. PCM runtimes have been already removed via soc_remove_pcm_runtimes(), while it's dereferenced later in soc_pcm_free() called via snd_card_free(). The fix is simple: just move the snd_card_free() call to the beginning of the whole procedure. This also gives another benefit: it guarantees that all operations have been shut down before actually releasing the resources, which was racy until now. Reported-and-tested-by: Robert Jarzmik <robert.jarzmik@free.fr> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Mark Brown <broonie@kernel.org> Cc: <stable@vger.kernel.org>
Diffstat (limited to 'sound')
-rw-r--r--sound/soc/soc-core.c5
1 files changed, 3 insertions, 2 deletions
diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index aae099c0e502..754e3ef8d7ae 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -2286,6 +2286,9 @@ static int soc_cleanup_card_resources(struct snd_soc_card *card)
list_for_each_entry(rtd, &card->rtd_list, list)
flush_delayed_work(&rtd->delayed_work);
+ /* free the ALSA card at first; this syncs with pending operations */
+ snd_card_free(card->snd_card);
+
/* remove and free each DAI */
soc_remove_dai_links(card);
soc_remove_pcm_runtimes(card);
@@ -2300,9 +2303,7 @@ static int soc_cleanup_card_resources(struct snd_soc_card *card)
if (card->remove)
card->remove(card);
- snd_card_free(card->snd_card);
return 0;
-
}
/* removes a socdev */

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