Re: Possible system call interface for LSM

sarnoldat_private

What happens when *length is less than zero?

On Thu, Aug 09, 2001 at 10:00:41AM -0700, richard offer wrote:
> +int sys_security (int module_id, int cmd, int copy, void *user_data, int *length)
> +{
> +	char *kern_data = ( copy ? NULL : user_data );
> +	int error = 0;
> +
> +	/* Make sure application is calling the right module */
> +	if (module_id != security_ops->module_id)
> +		return -ENOPKG;
> +
> +	if (copy && length && *length) {
> +		kern_data = kmalloc(*length, GFP_KERNEL);
> +		if (!kern_data) {
> +			error = -ENOMEM;
> +			goto out;
> +		}
> +
> +		if (copy_from_user(kern_data, user_data, *length)) {
> +			error = -EFAULT;
> +			goto out;
> +		}
> +	}
> +
> +	error = security_ops->syscall(cmd, kern_data, length);
> +	if (error)
> +		goto out;
> +
> +	if (copy && length) {
> +		if (copy_to_user(user_data, kern_data, *length)) {
> +			error = -EFAULT;
> +			goto out;
> +		}
> +	}
> +out:
> +	if (copy && kern_data)
> +		kfree(kern_data);
> +
> +	return error;
> +}

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