From: Alan Stern Date: Sat, 6 Mar 2010 20:04:03 +0000 (-0500) Subject: USB: fix usbfs regression X-Git-Tag: v2.6.31.13~3 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=194d2386083401a8a82379870a1fef7c24ca8723;p=thirdparty%2Fkernel%2Fstable.git USB: fix usbfs regression commit 7152b592593b9d48b33f8997b1dfd6df9143f7ec upstream. This patch (as1352) fixes a bug in the way isochronous input data is returned to userspace for usbfs transfers. The entire buffer must be copied, not just the first actual_length bytes, because the individual packets will be discontiguous if any of them are short. Reported-by: Markus Rechberger Signed-off-by: Alan Stern Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c index 52aabc7d4ba00..5ae4099fb4c17 100644 --- a/drivers/usb/core/devio.c +++ b/drivers/usb/core/devio.c @@ -1139,6 +1139,13 @@ static int proc_do_submiturb(struct dev_state *ps, struct usbdevfs_urb *uurb, free_async(as); return -ENOMEM; } + /* Isochronous input data may end up being discontiguous + * if some of the packets are short. Clear the buffer so + * that the gaps don't leak kernel data to userspace. + */ + if (is_in && uurb->type == USBDEVFS_URB_TYPE_ISO) + memset(as->urb->transfer_buffer, 0, + uurb->buffer_length); } as->urb->dev = ps->dev; as->urb->pipe = (uurb->type << 30) | @@ -1240,10 +1247,14 @@ static int processcompl(struct async *as, void __user * __user *arg) void __user *addr = as->userurb; unsigned int i; - if (as->userbuffer && urb->actual_length) - if (copy_to_user(as->userbuffer, urb->transfer_buffer, - urb->actual_length)) + if (as->userbuffer && urb->actual_length) { + if (urb->number_of_packets > 0) /* Isochronous */ + i = urb->transfer_buffer_length; + else /* Non-Isoc */ + i = urb->actual_length; + if (copy_to_user(as->userbuffer, urb->transfer_buffer, i)) goto err_out; + } if (put_user(as->status, &userurb->status)) goto err_out; if (put_user(urb->actual_length, &userurb->actual_length))