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Date: Tue, 20 Nov 2012 14:22:26 +0200
From: Jaakko Heinonen <jh@FreeBSD.org>
To: Baptiste Daroussin <bapt@FreeBSD.org>
Subject: Re: svn commit: r243328 - head/lib/libutil
Message-ID: <20121120122226.GA1828@a91-153-116-96.elisa-laajakaista.fi>
References: <201211200722.qAK7M7Im057617@svn.freebsd.org>
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Hi!

On 2012-11-20, Baptiste Daroussin wrote:
>   change mode the group file to 0644 after a successfull rename(2)
> 
>  int
>  gr_mkdb(void)
>  {
> -	return (rename(tempname, group_file));
> +	int ret;
> +
> +	ret = rename(tempname, group_file);
> +
> +	if (ret == 0)
> +		chmod(group_file, 0644);
> +
> +	return (ret);
>  }

Rename+chmod is not an atomic operation. There is a window when the file
has wrong permissions. Also, you don't check the return value of
chmod(). Maybe chmod first and then rename?

-- 
Jaakko