| Message ID | YIE7RrBPLWc3XtMg@mwanda |
|---|---|
| State | New |
| Headers | show |
| Series | usb: gadget: prevent a ternary sign expansion bug | expand |
Dan Carpenter <dan.carpenter@oracle.com> writes: > The problem is that "req->actual" is a u32, "req->status" is an int, and > iocb->ki_complete() takes a long. We would expect that a negative error > code in "req->status" would translate to a negative long value. > > But what actually happens is that because "req->actual" is a u32, the > error codes is type promoted to a high positive value and then remains > a positive value when it is cast to long. (No sign expansion). > > We can fix this by casting "req->status" to long. > > Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> I'm just going to assume your type promotion rank is correct :-) Acked-by: Felipe Balbi <balbi@kernel.org>
diff --git a/drivers/usb/gadget/legacy/inode.c b/drivers/usb/gadget/legacy/inode.c index 71e7d10dd76b..cd8e2737947b 100644 --- a/drivers/usb/gadget/legacy/inode.c +++ b/drivers/usb/gadget/legacy/inode.c @@ -498,7 +498,8 @@ static void ep_aio_complete(struct usb_ep *ep, struct usb_request *req) iocb->private = NULL; /* aio_complete() reports bytes-transferred _and_ faults */ - iocb->ki_complete(iocb, req->actual ? req->actual : req->status, + iocb->ki_complete(iocb, + req->actual ? req->actual : (long)req->status, req->status); } else { /* ep_copy_to_user() won't report both; we hide some faults */
The problem is that "req->actual" is a u32, "req->status" is an int, and iocb->ki_complete() takes a long. We would expect that a negative error code in "req->status" would translate to a negative long value. But what actually happens is that because "req->actual" is a u32, the error codes is type promoted to a high positive value and then remains a positive value when it is cast to long. (No sign expansion). We can fix this by casting "req->status" to long. Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> --- drivers/usb/gadget/legacy/inode.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)