PATCH: ctdb: buffer write beyond limits

[Volker Lendecke]

On Mon, Feb 18, 2019 at 08:19:52AM +0100, swen via samba-technical wrote:
>  data_read:
> -	num_ready = MIN(num_ready, queue->buffer.size - queue->buffer.length);
> +	num_ready = MIN(num_ready,
> +			queue->buffer.size -
> +				(queue->buffer.length + queue->buffer.offset));

Whenever I see buffer calculations without explicit overflow checks
I'm scared. So either add a very explicit comment explaining in 100%
simple words that the addition can never overflow and the subtraction
can never underflow or add the appropriate over/undeflow checks.

Thanks, Volker

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