From: Dan Carpenter <dan.carpenter@oracle.com>
To: kernel-janitors@vger.kernel.org
Subject: Re: [patch] usb: gadget: f_fs: signedness bug in __ffs_func_bind_do_descs()
Date: Wed, 10 Sep 2014 11:05:25 +0000 [thread overview]
Message-ID: <20140910110525.GP6549@mwanda> (raw)
In-Reply-To: <20140909120609.GB19760@mwanda>
On Tue, Sep 09, 2014 at 06:37:02PM +0200, Michal Nazarewicz wrote:
> On Tue, Sep 09 2014, Dan Carpenter <dan.carpenter@oracle.com> wrote:
> > On Tue, Sep 09, 2014 at 03:57:26PM +0200, Michal Nazarewicz wrote:
> >> On Tue, Sep 09 2014, Dan Carpenter <dan.carpenter@oracle.com> wrote:
> >> > Btw, there is a sparse warning:
> >> >
> >> > drivers/usb/gadget/function/f_fs.c:401:44: warning: Variable length array is used.
> >> >
> >> > The risk here is that the array would be too large. I don't know the
> >> > code well enough to say if it can be triggered, but from an outsider
> >> > perspective it looks scary (security implications). There should be a
> >> > comment explaining why it can't be used to overflow the 8k stack.
> >>
> >> n in that function can be at most 4
> >
> > I looked for where this limit is set but couldn't figure it out. Which
> > function is it?
>
> The limit is never explicitly set, but logic in this function guarantees
> it:
>
Ok. Thanks. I maybe could have found this on my own because I store
this sort of information in Smatch except that "ev" is an anonymous
struct.
regards,
dan carpenter
prev parent reply other threads:[~2014-09-10 11:05 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-09 12:06 [patch] usb: gadget: f_fs: signedness bug in __ffs_func_bind_do_descs() Dan Carpenter
2014-09-09 13:57 ` Michal Nazarewicz
2014-09-09 14:25 ` Dan Carpenter
2014-09-09 16:37 ` Michal Nazarewicz
2014-09-09 16:40 ` Felipe Balbi
2014-09-10 11:05 ` Dan Carpenter [this message]
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