4.5.10 on AIX 7.1 [possible solution]

[Albert Chin]

On Mon, May 29, 2017 at 09:15:10PM +0200, Volker Lendecke via samba-technical wrote:
> On Mon, May 29, 2017 at 01:26:52PM -0500, Albert Chin via samba-technical wrote:
> > AIX doesn't like 0-length arrays. If I modify:
> > 		uint8_t buf[fdlen];
> > to:
> > 		uint8_t buf[fdlen+1];
> > then things seem to work. Need to do some further testing.
> > 
> > So, what is the best wa to fix this?
> 
> Thanks for the analysis!
> 
> Does the attached patch also fix it?

Yes, it does, on both 4.5.10 and 4.6.4. Please push to master.

> Volker
> 
> -- 
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> From a551afbf8f1ca637aa0df7d14ff54d5c51bc735e Mon Sep 17 00:00:00 2001
> From: Volker Lendecke <vl at samba.org>
> Date: Mon, 29 May 2017 21:13:16 +0200
> Subject: [PATCH] lib: Fix illegal use of 0-length arrays
> 
> Found by albert chin (china at thewrittenword.com)
> 
> Signed-off-by: Volker Lendecke <vl at samba.org>
> ---
>  lib/util/msghdr.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/util/msghdr.c b/lib/util/msghdr.c
> index 4b88c1a..fec5446 100644
> --- a/lib/util/msghdr.c
> +++ b/lib/util/msghdr.c
> @@ -37,13 +37,19 @@ ssize_t msghdr_prep_fds(struct msghdr *msg, uint8_t *buf, size_t bufsize,
>  			msg->msg_control = NULL;
>  			msg->msg_controllen = 0;
>  		}
> -		return 0;
> +		/*
> +		 * C99 doesn't allow 0-length arrays
> +		 */
> +		return 1;
>  	}
>  	if (num_fds > INT8_MAX) {
>  		return -1;
>  	}
>  	if ((msg == NULL) || (cmsg_space > bufsize)) {
> -		return cmsg_space;
> +		/*
> +		 * C99 doesn't allow 0-length arrays
> +		 */
> +		return MAX(cmsg_space, 1);
>  	}
>  
>  	msg->msg_control = buf;
> -- 
> 2.1.4

-- 
albert chin (china at thewrittenword.com)