Re: [PATCH] t4062: stop using repetition in regex

From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Aug 8, 2017, 14:49 UTC
Message-ID: <alpine.DEB.2.21.1.1708081648130.11175@virtualbox>
In-Reply-To: <861dc875-7300-fe5a-1360-0ed546c8c2bb@web.de>

Hi René,

On Tue, 8 Aug 2017, René Scharfe wrote:

Show 8 quoted lines

> OpenBSD's regex library has a repetition limit (RE_DUP_MAX) of 255.
> That's the minimum acceptable value according to POSIX.  In t4062 we use
> 4096 repetitions in the test "-G matches", though, causing it to fail.
> 
> Do the same as the test "-S --pickaxe-regex" in the same file and search
> for a single zero instead.  That still suffices to trigger the buffer
> overrun in older versions (checked with b7d36ffca02^ and --valgrind on
> Linux), simplifies the test a bit, and avoids exceeding OpenBSD's limit.

I am afraid not. The 4096 is precisely the page size required to trigger the bug on Windows against which this regression test tries to safeguard.

Maybe simply disable the test on OpenBSD instead? Or guard the {4096} behind the MINGW prereq.

Ciao, Dscho