From: Dan Carpenter <dan.carpenter@oracle.com>
To: Felipe Balbi <balbi@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Alan Stern <stern@rowland.harvard.edu>,
Jens Axboe <axboe@kernel.dk>,
Felix Kuehling <Felix.Kuehling@amd.com>,
Andrew Morton <akpm@linux-foundation.org>,
"Gustavo A. R. Silva" <gustavoars@kernel.org>,
Masahiro Yamada <masahiroy@kernel.org>,
Zhang Qilong <zhangqilong3@huawei.com>,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
kernel-janitors@vger.kernel.org
Subject: [PATCH] usb: gadget: prevent a ternary sign expansion bug
Date: Thu, 22 Apr 2021 12:00:54 +0300 [thread overview]
Message-ID: <YIE7RrBPLWc3XtMg@mwanda> (raw)
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(-)
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 */
--
2.30.2
next reply other threads:[~2021-04-22 9:01 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-22 9:00 Dan Carpenter [this message]
2021-04-22 11:03 ` [PATCH] usb: gadget: prevent a ternary sign expansion bug Felipe Balbi
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