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authorTakashi Iwai <tiwai@suse.de>2017-05-24 10:19:45 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-06-14 13:16:26 +0200
commit9a9388953bdcd416f94991f3bd19ea9bc2b31930 (patch)
treee82d26d3fe1ce8a3c06981a964823cce5cdf9d55
parent54d12fbf54d4d40d2a47200150344bc001a29e96 (diff)
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ASoC: Fix use-after-free at card unregistration
commit 4efda5f2130da033aeedc5b3205569893b910de2 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-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 a1305f827a98..fa6b74a304a7 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -1775,6 +1775,9 @@ static int soc_cleanup_card_resources(struct snd_soc_card *card)
for (i = 0; i < card->num_aux_devs; i++)
soc_remove_aux_dev(card, i);
+ /* 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);
@@ -1786,9 +1789,7 @@ static int soc_cleanup_card_resources(struct snd_soc_card *card)
snd_soc_dapm_free(&card->dapm);
- snd_card_free(card->snd_card);
return 0;
-
}
/* removes a socdev */