From: 'Greg KH' <greg-U8xfFu+wG4EAvxtiuMwx3w@public•gmane.org>
To: David Laight <David.Laight-ZS65k/vG3HxXrIkS9f7CXA@public•gmane.org>
Cc: Petko Manolov <petkan-nPnTwAqkgEqakBO8gow8eQ@public•gmane.org>,
Ben Hutchings <ben-/+tVBieCtBitmTQ+vhA3Yw@public•gmane.org>,
"netdev-u79uwXL29TY76Z2rM5mHXA@public•gmane.org"
<netdev-u79uwXL29TY76Z2rM5mHXA@public•gmane.org>,
"linux-usb-u79uwXL29TY76Z2rM5mHXA@public•gmane.org"
<linux-usb-u79uwXL29TY76Z2rM5mHXA@public•gmane.org>
Subject: Re: [PATCH net 2/4] rtl8150: Use heap buffers for all register access
Date: Tue, 7 Feb 2017 13:42:04 +0100 [thread overview]
Message-ID: <20170207124204.GA11883@kroah.com> (raw)
In-Reply-To: <063D6719AE5E284EB5DD2968C1650D6DB027DB75-VkEWCZq2GCInGFn1LkZF6NBPR1lH4CV8@public.gmane.org>
On Tue, Feb 07, 2017 at 11:56:51AM +0000, David Laight wrote:
> From: Greg KH
> > Sent: 07 February 2017 10:52
> > To: Petko Manolov
> > Cc: Ben Hutchings; David Laight; netdev-u79uwXL29TY76Z2rM5mHXA@public•gmane.org; linux-usb-u79uwXL29TY76Z2rM5mHXA@public•gmane.org
> > Subject: Re: [PATCH net 2/4] rtl8150: Use heap buffers for all register access
> >
> > On Tue, Feb 07, 2017 at 12:34:52PM +0200, Petko Manolov wrote:
> > > On 17-02-06 16:25:20, Ben Hutchings wrote:
> > > > On Mon, Feb 06, 2017 at 04:09:18PM +0000, David Laight wrote:
> > > > > From: Ben Hutchings
> > > > [...]
> > > > > > + ret = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
> > > > > > + RTL8150_REQ_GET_REGS, RTL8150_REQT_READ,
> > > > > > + indx, 0, buf, size, 500);
> > > > > > + if (ret > 0 && ret <= size)
> > > > > > + memcpy(data, buf, ret);
> > > > >
> > > > > If ret > size something is horridly wrong.
> > > > > Silently not updating the callers buffer at all cannot be right.
> > > >
> > > > Yes, it seems strange to check this. I originally wrote this as ret >
> > > > 0, but then I checked the usbnet core and found __usbnet_read_cmd()
> > > > has the second comparison as well.
> > > >
> > > > > > + kfree(buf);
> > > > > > + return ret;
> > >
> > > Since we return what usb_control_msg() told us to return i assume the error code
> > > will be available to anybody who cares.
> > >
> > > > > I can't help feeling that it would be better to add a wrapper to
> > > > > usb_control_msg() that does the kmalloc() and memcpy()s and
> > > > > drop that into all the call sites.
> > > >
> > > > It might be. Right now I'm trying to patch up a bunch of regressions rather
> > > > than argue over an API change.
> > >
> > > Right, first thing first.
> > >
> > > I am in favor of changing the API, but this should not happen in the stable
> > > releases. I hope Greg will make up his mind and let us know.
> >
> > make up my mind about what? These are bugs, they should be fixed, I'm
> > not taking a total api change at this point in time, sorry.
>
> Adding a usb_control_msg_with_malloc() wrapper is a smaller change than those
> proposed. The smaller churn probably makes back porting other changes easier.
>
> Given the nature of this problem, and how common it seems to be,
> it is almost worth renaming usb_control_msg() itself so that all the
> callers are properly audited.
As this is something that we have been auditing for a decade now, I
don't think you will find all that many instances :)
But for now, fixes like this are fine, if someone wants to tackle the
larger issue here, with a new api function, that would be great.
thanks,
greg k-h
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next prev parent reply other threads:[~2017-02-07 12:42 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-04 16:54 [PATCH net 0/4] Fix on-stack USB buffers Ben Hutchings
2017-02-04 16:56 ` [PATCH net 1/4] pegasus: Use heap buffers for all register access Ben Hutchings
2017-02-05 0:30 ` Greg KH
2017-02-06 8:14 ` Petko Manolov
2017-02-06 8:28 ` Greg KH
2017-02-06 12:51 ` Petko Manolov
2017-02-06 13:21 ` Johan Hovold
2017-02-06 13:32 ` Johan Hovold
2017-02-06 13:46 ` Johan Hovold
2017-02-07 10:24 ` Petko Manolov
2017-02-07 10:45 ` Greg KH
[not found] ` <20170207104506.GB32583-U8xfFu+wG4EAvxtiuMwx3w@public.gmane.org>
2017-02-07 12:50 ` Petko Manolov
2017-02-06 13:30 ` David Laight
2017-02-07 18:32 ` Steve Calfee
2017-02-08 7:57 ` Petko Manolov
2017-02-04 16:56 ` [PATCH net 2/4] rtl8150: " Ben Hutchings
2017-02-06 8:10 ` Petko Manolov
[not found] ` <20170204165631.GW3442-/+tVBieCtBitmTQ+vhA3Yw@public.gmane.org>
2017-02-06 16:09 ` David Laight
2017-02-06 16:25 ` Ben Hutchings
2017-02-07 10:34 ` Petko Manolov
2017-02-07 10:51 ` Greg KH
2017-02-07 11:56 ` David Laight
[not found] ` <063D6719AE5E284EB5DD2968C1650D6DB027DB75-VkEWCZq2GCInGFn1LkZF6NBPR1lH4CV8@public.gmane.org>
2017-02-07 12:42 ` 'Greg KH' [this message]
2017-02-07 12:53 ` Petko Manolov
2017-02-07 13:01 ` Greg KH
2017-02-07 13:20 ` Petko Manolov
2017-02-07 14:14 ` David Laight
2017-02-07 14:52 ` Petko Manolov
[not found] ` <20170204165451.GU3442-/+tVBieCtBitmTQ+vhA3Yw@public.gmane.org>
2017-02-04 16:56 ` [PATCH net 3/4] catc: Combine failure cleanup code in catc_probe() Ben Hutchings
2017-02-04 16:57 ` [PATCH net 4/4] catc: Use heap buffer for memory size test Ben Hutchings
2017-02-07 15:07 ` [PATCH net 0/4] Fix on-stack USB buffers David Miller
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