Re: [PATCH 3/7] SLIM main patch

[Stephen Smalley <sds@tycho.nsa.gov>]

On Thu, 2006-10-19 at 13:48 -0700, Kylene Jo Hall wrote:
> --- linux-2.6.19-rc2/security/slim/slm_main.c	2006-10-19 12:05:58.000000000 -0700
> +++ linux-2.6.19-rc2/security/slim/slm_main.c	2006-10-19 12:11:37.000000000 -0700
> @@ -1130,6 +1103,34 @@ static int slm_socket_post_create(struct
>  	return 0;
>  }
>  
> +static int slm_file_receive(struct file *file)
> +{
> +	struct slm_isec_data *isec = file->f_dentry->d_inode->i_security;
> +	struct slm_tsec_data *tsec = current->security;
> +	struct slm_file_xattr level;
> +	int rc = 0;
> +
> +	spin_lock(&isec->lock);
> +	memcpy(&level, &isec->level, sizeof(struct slm_file_xattr));
> +	spin_unlock(&isec->lock);
> +
> +	spin_lock(&tsec->lock);
> +	if (file->f_mode & FMODE_READ) { /* IRAC(process) <= IAC(object) */
> +		if (!is_iac_less_than_or_exempt(&level, tsec->iac_r))
> +			rc = -EPERM;
> +	}
> +	if (file->f_mode & FMODE_WRITE) { /* IWXAC(process) >= IAC(object) */
> +		if (!is_iac_greater_than_or_exempt(&level, tsec->iac_wx))
> +			rc = -EPERM;
> +	}
> +	if (file->f_mode & FMODE_EXEC) { /* IWXAC(process) <= IAC(object) */
> +		if (!is_iac_less_than_or_exempt(&level, tsec->iac_wx))
> +			rc = -EPERM;
> +	}
> +	spin_unlock(&tsec->lock);
> +	return rc;
> +}

Also, given your security model, why do you always have this hook deny
access rather than attempting to demote the task?

-- 
Stephen Smalley
National Security Agency

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