Re: [PATCH] tcp_lp: use 64-bit arithmetic instead of 32-bit

From: Gustavo A. R. Silva
Date: Thu Feb 01 2018 - 21:34:10 EST


Hi David,

Quoting David Laight <David.Laight@xxxxxxxxxx>:

> The question you need to ask is 'can it overflow 32bit maths', otherwise
> you are potentially making the system do extra work for no reason.
>

Yeah, I get your point and it seems that in this particular case there
is no risk of a 32bit overflow, but in general and IMHO as the code
evolves, the use of incorrect arithmetic may have security
implications in the future, so I advocate for code correctness in this
case.

Even if the variable are 64bit you still need to worry (maybe less)
about arithmetic overflow.
The only real way to avoid overflow is to understand the domain
of the values being used.


Yep, that's correct.

Thanks for the feedback.
--
Gustavo