Re: [PATCH] smack:beyond ARRAY_SIZE of data

[Casey Schaufler <casey@schaufler-ca.com>]

Roel Kluin wrote:
> Do not go beyond ARRAY_SIZE of data
>
> Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
> ---
> diff --git a/security/smack/smackfs.c b/security/smack/smackfs.c
> index e03a7e1..7407e5c 100644
> --- a/security/smack/smackfs.c
> +++ b/security/smack/smackfs.c
> @@ -797,7 +797,7 @@ static ssize_t smk_write_netlbladdr(struct file *file, const char __user *buf,
>  		return -EPERM;
>  	if (*ppos != 0)
>  		return -EINVAL;
> -	if (count < SMK_NETLBLADDRMIN || count > SMK_NETLBLADDRMAX)
> +	if (count < SMK_NETLBLADDRMIN || count >= SMK_NETLBLADDRMAX)
>   

There is a problem here, but this won't fix it. The buffer needs to be
allocated bigger than the potential contents (should be
SMK_NETLBLADDRMAX + 1 instead of SMK_NETLBLADDRMAX. Your patch will clip
the last byte off of a maximum length specification.



>  		return -EINVAL;
>  	if (copy_from_user(data, buf, count) != 0)
>  		return -EFAULT;
>
> --
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