From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
To: John Johansen <john.johansen@canonical.com>,
James Morris <jmorris@namei.org>,
"Serge E. Hallyn" <serge@hallyn.com>
Cc: linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] apparmor: Replace zero-length array with flexible-array member
Date: Thu, 27 Feb 2020 06:53:44 -0600 [thread overview]
Message-ID: <4c8bf961-1d0d-9a63-3b1b-3aa6acb55179@embeddedor.com> (raw)
In-Reply-To: <20200211210427.GA28952@embeddedor>
Hi all,
Friendly ping: Who can take this?
Thanks
--
Gustavo
On 2/11/20 15:04, 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
> inadvertenly introduced[3] to the codebase from now on.
>
> This issue was found with the help of Coccinelle.
>
> [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")
>
> Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
> ---
> security/apparmor/apparmorfs.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/security/apparmor/apparmorfs.c b/security/apparmor/apparmorfs.c
> index fefee040bf79..cc81080efb63 100644
> --- a/security/apparmor/apparmorfs.c
> +++ b/security/apparmor/apparmorfs.c
> @@ -804,7 +804,7 @@ static ssize_t query_label(char *buf, size_t buf_len,
> struct multi_transaction {
> struct kref count;
> ssize_t size;
> - char data[0];
> + char data[];
> };
>
> #define MULTI_TRANSACTION_LIMIT (PAGE_SIZE - sizeof(struct multi_transaction))
>
prev parent reply other threads:[~2020-02-27 12:51 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-11 21:04 [PATCH] apparmor: Replace zero-length array with flexible-array member Gustavo A. R. Silva
2020-02-27 12:53 ` Gustavo A. R. Silva [this message]
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