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Date:   Sun, 1 Oct 2023 15:21:27 -0700
From:   Kees Cook <keescook@chromium.org>
To:     Julia Lawall <julia.lawall@inria.fr>
Cc:     Kees Cook <kees@kernel.org>,
        Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
        Ian Abbott <abbotti@mev.co.uk>,
        H Hartley Sweeten <hsweeten@visionengravers.com>,
        "Gustavo A. R. Silva" <gustavoars@kernel.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>, linux-kernel@vger.kernel.org,
        kernel-janitors@vger.kernel.org, linux-hardening@vger.kernel.org,
        llvm@lists.linux.dev
Subject: Re: [PATCH] comedi: Annotate struct comedi_lrange with __counted_by
Message-ID: <202310011515.D4C9184@keescook>
References: <5c3b7459b820e22e2ac6ce892d4aadcc119cc919.1696065263.git.christophe.jaillet@wanadoo.fr>
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On Sun, Oct 01, 2023 at 02:22:17PM -0700, Kees Cook wrote:
> On Sun, Oct 01, 2023 at 02:05:46PM -0700, Kees Cook wrote:
> > On Sun, Oct 01, 2023 at 09:14:02PM +0200, Julia Lawall wrote:
> > > Kees,
> > > 
> > > You can try the following.
> > 
> > Cool! Yeah, this finds the example:
> > 
> > drivers/comedi/drivers/rti800.c:74: struct comedi_lrange: field at offset 0 is the counter for the flex array
> > drivers/comedi/drivers/rti800.c:83: struct comedi_lrange: field at offset 0 is the counter for the flex array
> > drivers/comedi/drivers/rti800.c:92: struct comedi_lrange: field at offset 0 is the counter for the flex array
> > 
> > I'll run it on the whole codebase...
> 
> It found only the struct comedi_lrange instances, but that's good to
> know. :)

On a related note, why doesn't this work?

@allocated@
identifier STRUCT, ARRAY;
expression COUNT;
struct STRUCT *PTR;
identifier ALLOC;
type ELEMENT_TYPE;
@@

        PTR = ALLOC(..., sizeof(\(*PTR\|struct STRUCT\)) +
                         COUNT * sizeof(\(*PTR->ARRAY\|PTR->ARRAY[0]\|ELEMENT_TYPE\)), ...);


minus: parse error: 
  File "alloc.cocci", line 15, column 34, charpos = 485
  around = 'struct',
  whole content =       PTR = ALLOC(..., sizeof(\(*PTR\|struct STRUCT\)) +

if I drop "struct", then it complains about ELEMENT_TYPE...

-Kees

-- 
Kees Cook