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ALSA: usb-audio: Fix potential memory leaks at error path for UMP open

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The allocation and initialization errors at alloc_midi_urbs() that is
called at MIDI 2.0 / UMP device are supposed to be handled at the
caller side by invoking free_midi_urbs().  However, free_midi_urbs()
loops only for ep->num_urbs entries, and since ep->num_entries wasn't
updated yet at the allocation / init error in alloc_midi_urbs(), this
entry won't be released.

The intention of free_midi_urbs() is to release the whole elements, so
change the loop size to NUM_URBS to scan over all elements for fixing
the missed releases.

Also, the call of free_midi_urbs() is missing at
snd_usb_midi_v2_open().  Although it'll be released later at
reopen/close or disconnection, it's better to release immediately at
the error path.

Fixes: ff49d1df79ae ("ALSA: usb-audio: USB MIDI 2.0 UMP support")
Reported-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Closes: https://lore.kernel.org/r/fc275ed315b9157952dcf2744ee7bdb78defdb5f.1693746347.git.christophe.jaillet@wanadoo.fr
Link: https://lore.kernel.org/r/20230905054511.20502-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Takashi Iwai 2023-09-05 07:45:11 +02:00
parent 99bf5b0baa
commit b1757fa30e
1 changed files with 5 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
sound/usb/midi2.c
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@ -265,7 +265,7 @@ static void free_midi_urbs(struct snd_usb_midi2_endpoint *ep)
if (!ep) if (!ep)
return; return;
for (i = 0; i < ep->num_urbs; ++i) { for (i = 0; i < NUM_URBS; ++i) {
ctx = &ep->urbs[i]; ctx = &ep->urbs[i];
if (!ctx->urb) if (!ctx->urb)
break; break;
@ -279,6 +279,7 @@ static void free_midi_urbs(struct snd_usb_midi2_endpoint *ep)
} }
/* allocate URBs for an EP */ /* allocate URBs for an EP */
/* the callers should handle allocation errors via free_midi_urbs() */
static int alloc_midi_urbs(struct snd_usb_midi2_endpoint *ep) static int alloc_midi_urbs(struct snd_usb_midi2_endpoint *ep)
{ {
struct snd_usb_midi2_urb *ctx; struct snd_usb_midi2_urb *ctx;
@ -351,8 +352,10 @@ static int snd_usb_midi_v2_open(struct snd_ump_endpoint *ump, int dir)
return -EIO; return -EIO;
if (ep->direction == STR_OUT) { if (ep->direction == STR_OUT) {
err = alloc_midi_urbs(ep); err = alloc_midi_urbs(ep);
if (err) if (err) {
free_midi_urbs(ep);
return err; return err;
}
} }
return 0; return 0;
} }