linux-kernel - Re: [kernel-hardening] [PATCH v8 2/4] GCC plugin infrastructure

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <573D782D.10392.75A275C@pageexec.freemail.hu>
Date:	Thu, 19 May 2016 10:24:13 +0200
From:	"PaX Team" <pageexec@...email.hu>
To:	Emese Revfy <re.emese@...il.com>,
	kernel-hardening@...ts.openwall.com,
	Michael Ellerman <mpe@...erman.id.au>
CC:	Andrew Donnellan <andrew.donnellan@....ibm.com>,
	linux-kbuild@...r.kernel.org, spender@...ecurity.net,
	mmarek@...e.com, keescook@...omium.org, linux@...musvillemoes.dk,
	fengguang.wu@...el.com, dvyukov@...gle.com,
	linux-kernel@...r.kernel.org, david.brown@...aro.org,
	yamada.masahiro@...ionext.com,
	linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>,
	Daniel Axtens <dja@...ens.net>
Subject: Re: [kernel-hardening] [PATCH v8 2/4] GCC plugin infrastructure

On 19 May 2016 at 16:22, Michael Ellerman wrote:

> On Wed, 2016-05-18 at 12:33 +0200, Emese Revfy wrote:
> > Did you test the plugins with all gcc versions (4.5-6)?
> 
> What's the concern about gcc versions? Just not breaking the build on old
> compilers?

the earlier plugin capable gcc versions used to install gcc headers in a somewhat
ad-hoc manner resulting in compile time breakage for plugins and since some of
those potentially missing headers are target specific, each target arch should
be verified before enabling plugin support on them. things have much improved with
gcc 5 (see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61176) though there's still
an occasional missing header but with wider use of plugins they will hopefully be
discovered earlier now. perhaps linux-arch should be cc'ed on the plugin infrastructure
so that arch maintainers are aware of this?

> I'm pretty sure powerpc big endian still builds with gcc 4.4.
> 
> However if Andrew's only tested on little endian, then that select should be
> guarded with an "if CPU_LITTLE_ENDIAN". And to build LE you need gcc >= 4.9.

i guess that's part of the target tuple so in general arch maintainers should test
the target tuples used on their arch with all the supported gcc versions (speaking
of CC, not HOSTCC/HOSTCXX).

cheers,
 PaX Team