From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dan Carpenter Date: Fri, 11 Oct 2019 13:58:56 +0000 Subject: Re: [PATCH] USB: legousbtower: fix a signedness bug in tower_probe() Message-Id: <20191011135855.GE4774@kadam> List-Id: References: <20191011133525.GB22905@mwanda> <5DA088DE.5040902@bfs.de> In-Reply-To: <5DA088DE.5040902@bfs.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: walter harms Cc: Juergen Stuber , Johan Hovold , Greg Kroah-Hartman , legousb-devel@lists.sourceforge.net, linux-usb@vger.kernel.org, kernel-janitors@vger.kernel.org On Fri, Oct 11, 2019 at 03:51:26PM +0200, walter harms wrote: > > > Am 11.10.2019 15:35, schrieb Dan Carpenter: > > The problem is that sizeof() is unsigned long so negative error codes > > are type promoted to high positive values and the condition becomes > > false. > > > > Fixes: 1d427be4a39d ("USB: legousbtower: fix slab info leak at probe") > > Signed-off-by: Dan Carpenter > > --- > > drivers/usb/misc/legousbtower.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/usb/misc/legousbtower.c b/drivers/usb/misc/legousbtower.c > > index 9d4c52a7ebe0..835908fe1e65 100644 > > --- a/drivers/usb/misc/legousbtower.c > > +++ b/drivers/usb/misc/legousbtower.c > > @@ -881,7 +881,7 @@ static int tower_probe (struct usb_interface *interface, const struct usb_device > > get_version_reply, > > sizeof(*get_version_reply), > > 1000); > > - if (result < sizeof(*get_version_reply)) { > > + if (result < 0 || result < sizeof(*get_version_reply)) { > > if (result >= 0) > > result = -EIO; > > dev_err(idev, "get version request failed: %d\n", result); > > i am not an USB expert but it seems that this is a complicated way > to check for result != sizeof(*get_version_reply). Yeah. You're right. That would look nicer. I will resend. regards, dan carpenter