From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Serge E. Hallyn" <serge@hallyn.com>
Date: Mon, 12 Jul 2010 00:10:22 +0000
Subject: Re: [patch] cgroups: save space for the terminator
Message-Id: <20100712001022.GA6832@hallyn.com>
List-Id: <kernel-janitors.vger.kernel.org>
References: <20100710105429.GW19184@bicker>
In-Reply-To: <20100710105429.GW19184@bicker>
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To: Dan Carpenter <error27@gmail.com>, Paul Menage <menage@google.com>, Li Zefan <lizf@cn.fujitsu.com>, Andrew Morton <akpm@linux-foundation.org>, KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>, Ben Blum <bblum@andrew.cmu.edu>, containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org

Quoting Dan Carpenter (error27@gmail.com):
> The original code didn't leave enough space for a NULL terminator.
> These strings are copied with strcpy() into fixed length buffers in
> cgroup_root_from_opts().
>  
> Signed-off-by: Dan Carpenter <error27@gmail.com>

Hmm, yes - the fact that kstrndup() allocs len+1 probably threw off
the author of these original lines.  Thanks for spotting this!

Acked-by: Serge E. Hallyn <serge@hallyn.com>


> diff --git a/kernel/cgroup.c b/kernel/cgroup.c
> index 3ac6f5b..a942820 100644
> --- a/kernel/cgroup.c
> +++ b/kernel/cgroup.c
> @@ -1102,7 +1102,7 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
>  			if (opts->release_agent)
>  				return -EINVAL;
>  			opts->release_agent > -				kstrndup(token + 14, PATH_MAX, GFP_KERNEL);
> +				kstrndup(token + 14, PATH_MAX - 1, GFP_KERNEL);
>  			if (!opts->release_agent)
>  				return -ENOMEM;
>  		} else if (!strncmp(token, "name=", 5)) {
> @@ -1123,7 +1123,7 @@ static int parse_cgroupfs_options(char *data, struct cgroup_sb_opts *opts)
>  			if (opts->name)
>  				return -EINVAL;
>  			opts->name = kstrndup(name,
> -					      MAX_CGROUP_ROOT_NAMELEN,
> +					      MAX_CGROUP_ROOT_NAMELEN - 1,
>  					      GFP_KERNEL);
>  			if (!opts->name)
>  				return -ENOMEM;
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