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usb: gadget: prevent a ternary sign expansion bug 

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.

Acked-by: Felipe Balbi <balbi@kernel.org>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/YIE7RrBPLWc3XtMg@mwanda
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Dan Carpenter 2021-04-22 12:00:54 +03:00 committed by Greg Kroah-Hartman
parent f88359e158
commit 3343f376d4
1 changed files with 2 additions and 1 deletions
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3
drivers/usb/gadget/legacy/inode.c
View File

@ -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 */