From: Rich Felker <dalias@libc.org>
To: musl@lists.openwall.com
Subject: Re: RTLD_LAZY deferred symbol binding
Date: Wed, 11 Dec 2019 08:19:50 -0500 [thread overview]
Message-ID: <20191211131950.GM1666@brightrain.aerifal.cx> (raw)
In-Reply-To: <4346191576065348@iva8-3634a30a817d.qloud-c.yandex.net>
On Wed, Dec 11, 2019 at 02:55:48PM +0300, Scherbatiy Alexander wrote:
> Thank you. It works.
>
> I looked at the ld help on linux Alpine and it shows
> > ld --help
> > -z lazy Mark object lazy runtime binding (default)
>
> Should the lazy option be used by default
No, it's really a bug to be relying on this behavior, as it precludes
much-wanted hardening and is not well-defined per the supported
standards. Deferred binding was added for the sake of a very small but
important and stubborn set of software (i.e. Xorg) that was depending
on lazy binding and where musl-based dists were needing messy hacks to
make it work without (explicit load order of modules in xorg.conf).
The software that needs this behavior can be built with -z lazy as
needed. This is not unique to musl; it applies to hardened glibc
toolchains/distros where bindnow is default, too.
> or the documentation needs to be updated?
That's the documentation for ld, which applies if you invoke ld as a
command. That's not how you link hosted software. It's linked by
invoking $(CC) (e.g. gcc) which may be the part passing -z now; I
forget. If the default is actually changed in ld, then yes ld should
be patched to print the default it was configured with accurately (and
I would think such a patch would be acceptable for upstream).
Rich
next prev parent reply other threads:[~2019-12-11 13:19 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-11 10:09 Scherbatiy Alexander
2019-12-11 10:35 ` Szabolcs Nagy
2019-12-11 11:55 ` Scherbatiy Alexander
2019-12-11 13:19 ` Rich Felker [this message]
[not found] ` <4372011576065223@myt5-7210d748eb79.qloud-c.yandex.net>
2019-12-11 13:11 ` Szabolcs Nagy
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