Re: [PATCH] blame: prefer xsnprintf to strcpy for colors

From: Jeff King <peff@peff.net>
Date: Jul 13, 2018, 21:04 UTC
Message-ID: <20180713210452.GA18909@sigill.intra.peff.net>
In-Reply-To: <CAGZ79kakrS_tk=x4Rb9qSu9e4RVSJ=J64eOdasKhOy=g8kV68w@mail.gmail.com>

On Fri, Jul 13, 2018 at 01:58:05PM -0700, Stefan Beller wrote:

Show 6 quoted lines

> > I'm sad that this strcpy() wasn't caught in review. IMHO we should avoid
> > that function altogether, even when we _think_ it can't trigger an
> > overflow. That's easier to reason about (and makes auditing easier).
> 
> Can we somehow automatically find "bad code" either in pathces
> or in new code (such as pu), e.g. as a coccicheck for these functions?

I'd be happy to declare strcpy() totally banned (and it more or less is). I found this with a simple "git grep", though it seems like a trivial application of coccinelle to find it. The question is what to convert it into. xsnprintf() is often a good choice, but not always (e.g., if the destination isn't an array, we'd have to get the size from somewhere else).

I wouldn't be surprised if there's a way to ask coccinelle to convert the easy cases and barf with an error on the hard cases or something. I don't know the tool very well.

-Peff