linux-kernel - Re: [patch] module: static checker complains about negative values

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Message-ID: <20140520081957.GD15585@mwanda>
Date:	Tue, 20 May 2014 11:19:58 +0300
From:	Dan Carpenter <dan.carpenter@...cle.com>
To:	Rusty Russell <rusty@...tcorp.com.au>
Cc:	linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: Re: [patch] module: static checker complains about negative values

On Tue, May 20, 2014 at 11:16:04AM +0930, Rusty Russell wrote:
> Dan Carpenter <dan.carpenter@...cle.com> writes:
> 
> > We cap "stat.size" at INT_MAX but we don't check for negative values so
> > my static checker complains.  At this point, you already have control of
> > the kernel and if you start passing negative values here then you
> > deserve what happens next.
> >
> > On 64 bit systems the vmalloc() will definitely fail.  On 32 bit systems
> > we truncate the upper 32 bits away so that could succeed.  I haven't
> > followed it further than that.
> >
> > Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>
> 
> If vfs_getattr() returns a negative stat.size, we have worse problems.
> 
> I'd rather see you sprinkle assertions like that into the code, so we
> can make sure that can't happen for any fs's getattr().

Yeah.  I was lazy.  Sorry.  I can just hand edit my database to say that
i_size_read() returns a reasonable number...

regards,
dan carpenter

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