From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: linux-kernel@vger.kernel.org, Kees Cook <keescook@chromium.org>,
"David S. Miller" <davem@davemloft.net>,
linux-crypto@vger.kernel.org, netdev@vger.kernel.org,
linux-usb@vger.kernel.org
Subject: Re: [PATCH] treewide: Replace zero-length arrays with flexible-array member
Date: Tue, 11 Feb 2020 13:20:36 -0600 [thread overview]
Message-ID: <3fdbb16a-897c-aa5b-d45d-f824f6810412@embeddedor.com> (raw)
In-Reply-To: <20200211183229.GA1938663@kroah.com>
On 2/11/20 12:32, Greg KH wrote:
> On Tue, Feb 11, 2020 at 11:41:26AM -0600, Gustavo A. R. Silva wrote:
>> The current codebase makes use of the zero-length array language
>> extension to the C90 standard, but the preferred mechanism to declare
>> variable-length types such as these ones is a flexible array member[1][2],
>> introduced in C99:
>>
>> struct foo {
>> int stuff;
>> struct boo array[];
>> };
>>
>> By making use of the mechanism above, we will get a compiler warning
>> in case the flexible array does not occur last in the structure, which
>> will help us prevent some kind of undefined behavior bugs from being
>> unadvertenly introduced[3] to the codebase from now on.
>>
>> All these instances of code were found with the help of the following
>> Coccinelle script:
>>
>> @@
>> identifier S, member, array;
>> type T1, T2;
>> @@
>>
>> struct S {
>> ...
>> T1 member;
>> T2 array[
>> - 0
>> ];
>> };
>>
>> [1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
>> [2] https://github.com/KSPP/linux/issues/21
>> [3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")
>>
>> NOTE: I'll carry this in my -next tree for the v5.6 merge window.
>
> Why not carve this up into per-subsystem patches so that we can apply
> them to our 5.7-rc1 trees and then you submit the "remaining" that don't
> somehow get merged at that timeframe for 5.7-rc2?
>
Yep, sounds good. I'll do that.
Thanks
--
Gustavo
next prev parent reply other threads:[~2020-02-11 19:18 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-11 17:41 [PATCH] treewide: Replace zero-length arrays with flexible-array member Gustavo A. R. Silva
2020-02-11 18:32 ` Greg KH
2020-02-11 19:20 ` Gustavo A. R. Silva [this message]
2020-02-11 19:32 ` Kees Cook
2020-02-11 19:38 ` Greg KH
2020-02-11 19:54 ` Gustavo A. R. Silva
2020-02-11 20:12 ` Kees Cook
2020-02-11 20:30 ` Gustavo A. R. Silva
2020-02-11 19:35 ` Kees Cook
2020-02-11 20:16 ` Gustavo A. R. Silva
2020-02-12 8:00 ` Geert Uytterhoeven
2020-02-12 8:36 ` Kars de Jong
2020-02-13 11:09 ` Geert Uytterhoeven
2020-02-13 11:11 ` Ard Biesheuvel
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