[PATCH 37/69] ALSA: usx2y: check for failure of usb_alloc_urb()

Greg Kroah-Hartman
2021-05-03T12:02:31Z

While it is almost impossible to hit an error calling usb_alloc_urb(),
to make systems like syzbot which does error injection, and some static
analysis tools happy, properly handle errors on this path by unwinding
the previously allocated urbs and freeing them.

Cc: Takashi Iwai <tiwai@suse.de>
Cc: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
sound/usb/usx2y/usb_stream.c | 21 +++++++++++++++++++--
1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/sound/usb/usx2y/usb_stream.c b/sound/usb/usx2y/usb_stream.c
index 6bba17bf689a..1091ea96a29a 100644
--- a/sound/usb/usx2y/usb_stream.c
+++ b/sound/usb/usx2y/usb_stream.c
@@ -88,18 +88,35 @@ static int init_urbs(struct usb_stream_kernel *sk, unsigned use_packsize,
sizeof(struct usb_stream_packet) *
s->inpackets;
int u;
+ int i;
+ int err = -ENOMEM;

for (u = 0; u < USB_STREAM_NURBS; ++u) {
+ sk->outurb[u] = NULL;
sk->inurb[u] = usb_alloc_urb(sk->n_o_ps, GFP_KERNEL);
+ if (!sk->inurb[u])
+ goto error;
sk->outurb[u] = usb_alloc_urb(sk->n_o_ps, GFP_KERNEL);
+ if (!sk->outurb[u])
+ goto error;
}
+ u--;

if (init_pipe_urbs(sk, use_packsize, sk->inurb, indata, dev, in_pipe) ||
init_pipe_urbs(sk, use_packsize, sk->outurb, sk->write_page, dev,
- out_pipe))
- return -EINVAL;
+ out_pipe)) {
+ err = -EINVAL;
+ goto error;
+ }

return 0;
+
+error:
+ for (i = 0; i <= u; ++i) {
+ usb_free_urb(sk->inurb[i]);
+ usb_free_urb(sk->outurb[i]);
+ }
+ return err;
}

--
2.31.1