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authorJohan Hovold <johan@kernel.org>2019-12-20 10:31:34 +0100
committerTakashi Iwai <tiwai@suse.de>2019-12-20 11:31:46 +0100
commit0141254b0a74b37aa7eb13d42a56adba84d51c73 (patch)
tree1095e51d158b7daa9faa3bc6080d22feff6ffd03 /sound/usb/pcm.c
parent66c5d718e5a6f80153b5e8d6ad8ba8e9c3320839 (diff)
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ALSA: usb-audio: fix set_format altsetting sanity check
Make sure to check the return value of usb_altnum_to_altsetting() to avoid dereferencing a NULL pointer when the requested alternate settings is missing. The format altsetting number may come from a quirk table and there does not seem to be any other validation of it (the corresponding index is checked however). Fixes: b099b9693d23 ("ALSA: usb-audio: Avoid superfluous usb_set_interface() calls") Cc: stable <stable@vger.kernel.org> # 4.18 Signed-off-by: Johan Hovold <johan@kernel.org> Link: https://lore.kernel.org/r/20191220093134.1248-1-johan@kernel.org Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/usb/pcm.c')
-rw-r--r--sound/usb/pcm.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index 96298c767c76..a11c8150af58 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -506,9 +506,9 @@ static int set_format(struct snd_usb_substream *subs, struct audioformat *fmt)
if (WARN_ON(!iface))
return -EINVAL;
alts = usb_altnum_to_altsetting(iface, fmt->altsetting);
- altsd = get_iface_desc(alts);
- if (WARN_ON(altsd->bAlternateSetting != fmt->altsetting))
+ if (WARN_ON(!alts))
return -EINVAL;
+ altsd = get_iface_desc(alts);
if (fmt == subs->cur_audiofmt && !subs->need_setup_fmt)
return 0;