Re: strncpy is not a safe version of strcpy

From: Noah Misch <noah(at)leadboat(dot)com>
To: David Rowley <dgrowleyml(at)gmail(dot)com>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Kevin Grittner <kgrittn(at)ymail(dot)com>, Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, Tomas Vondra <tv(at)fuzzy(dot)cz>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: strncpy is not a safe version of strcpy
Date: 2014-08-16 03:26:55
Message-ID: 20140816032655.GA361872@tornado.leadboat.com
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On Sat, Aug 16, 2014 at 10:38:39AM +1200, David Rowley wrote:
> On Thu, Aug 14, 2014 at 4:13 PM, Noah Misch <noah(at)leadboat(dot)com> wrote:
>
> > I share your (Kevin's) discomfort with our use of strlcpy(). I wouldn't
> > mind
> > someone replacing most strlcpy()/snprintf() calls with calls to wrappers
> > that
> > ereport(ERROR) on truncation. Though as reliability problems go, this one
> > has
> > been minor.
> >
> >
> Or maybe it would be better to just remove the restriction and just palloc
> something of the correct size?
> Although, that sounds like a much larger patch. I'd vote that the strlcpy
> should be used in the meantime.

I agree that, in principle, dynamic allocation might be better still. I also
agree that it would impose more code churn, for an awfully-narrow benefit.

Barring objections, I will commit your latest patch with some comments about
why truncation is harmless for those two particular calls.

--
Noah Misch
EnterpriseDB http://www.enterprisedb.com

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