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Date: Mon, 12 Jul 2010 13:04:58 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Dan Carpenter <error27@gmail.com>
Cc: Eric Van Hensbergen <ericvh@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Abhishek Kulkarni <adkulkar@umail.iu.edu>,
        Venkateswararao Jujjuri <jvrao@us.ibm.com>,
        linux-kernel@vger.kernel.org, Tilman Sauerbeck <tilman@code-monkey.de>,
        netdev@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: [patch] 9p: strlen() doesn't count the terminator
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On Sat, 10 Jul 2010 11:51:54 +0200
Dan Carpenter <error27@gmail.com> wrote:

> This is an off by one bug because strlen() doesn't count the NULL
> terminator.  We strcpy() addr into a fixed length array of size
> UNIX_PATH_MAX later on.
> 
> The addr variable is the name of the device being mounted.
> 
> CC: stable@kernel.org
> Signed-off-by: Dan Carpenter <error27@gmail.com>
> 
> diff --git a/net/9p/trans_fd.c b/net/9p/trans_fd.c
> index 98ce9bc..c85109d 100644
> --- a/net/9p/trans_fd.c
> +++ b/net/9p/trans_fd.c
> @@ -948,7 +948,7 @@ p9_fd_create_unix(struct p9_client *client, const char *addr, char *args)
>  
>  	csocket = NULL;
>  
> -	if (strlen(addr) > UNIX_PATH_MAX) {
> +	if (strlen(addr) >= UNIX_PATH_MAX) {
>  		P9_EPRINTK(KERN_ERR, "p9_trans_unix: address too long: %s\n",
>  			addr);
>  		return -ENAMETOOLONG;

This bug doesn't strike me as serious enough to warrant backporting the fix
into -stable.  What was your thinking there?