This is the mail archive of the
mailing list for the glibc project.
Re: [PATCH][BZ #17250] Static dlopen default library search path fix
- From: "Maciej W. Rozycki" <macro at linux-mips dot org>
- To: Mike Frysinger <vapier at gentoo dot org>
- Cc: Andreas Schwab <schwab at suse dot de>, Roland McGrath <roland at hack dot frob dot com>, Ondřej Bílka <neleai at seznam dot cz>, Allan McRae <allan at archlinux dot org>, libc-alpha at sourceware dot org
- Date: Wed, 12 Aug 2015 15:50:51 +0100 (BST)
- Subject: Re: [PATCH][BZ #17250] Static dlopen default library search path fix
- Authentication-results: sourceware.org; auth=none
- References: <alpine dot DEB dot 1 dot 10 dot 1401172303320 dot 4268 at tp dot orcam dot me dot uk> <20140117233957 dot 64E307441B at topped-with-meat dot com> <alpine dot DEB dot 1 dot 10 dot 1401271320170 dot 4268 at tp dot orcam dot me dot uk> <alpine dot DEB dot 1 dot 10 dot 1401291054290 dot 4268 at tp dot orcam dot me dot uk> <mvmfv3zxkhk dot fsf at hawking dot suse dot de> <alpine dot LFD dot 2 dot 20 dot 1508041538290 dot 1410 at eddie dot linux-mips dot org> <mvmvbcvvz1b dot fsf at hawking dot suse dot de> <alpine dot LFD dot 2 dot 20 dot 1508041948170 dot 1410 at eddie dot linux-mips dot org> <20150806060657 dot GW26572 at vapier> <alpine dot LFD dot 2 dot 20 dot 1508062244350 dot 28573 at eddie dot linux-mips dot org> <20150807031507 dot GH30077 at vapier>
On Thu, 6 Aug 2015, Mike Frysinger wrote:
> > > > I'm not prepared to properly regression-test a change right away, but
> > > > meanwhile can you try the below as a proposed fix? Also I'm not sure
> > > > offhand how to make a test case that covers this issue, but I'll be happy
> > > > to accept ideas and implement them.
> > >
> > > two were posted to the bug. if you use tests-static in the Makefile,
> > > should be fairly easy to add to the tree and check the result.
> > Except that they cover the usual system-installed use case and we run our
> > test suite over uninstalled libraries. Normally that does not matter, but
> > here it does. Unless I'm missing something that is, am I?
> the test requires:
> - it be statically linked
> -> use tests-static in the makefile
> - the db accessed contains the data we request
> -> nptl/tst-setuid1.c seems to already assume "nobody" is a valid acct
> - it have access to the nss libs to load
> -> set LD_LIBRARY_PATH to the local paths using the xxx-env hooks if
> existing run logic doesn't already do it
> what other external deps did you have in mind ?
> i just tested it over here and it semed fine:
> $ gcc test.c -B. -static
> $ LD_LIBRARY_PATH=$PWD/nis:$PWD/nss:$PWD:$PWD/elf strace -e file ./a.out
> <all libs are loaded from $PWD>
> /etc/nsswitch.conf & /etc/passwd are read, but i think our tests already
> rely on that ...
The bug affects any modules loaded dynamically from a static executable,
so a dependency upon NSS having been configured in a particular way (mind
the `--enable-static-nss' `configure' option) is not required. An
explicit test case triggering the problem is better than one indirectly
relying on other subsystems anyway. Such code can be easily written based
on the nature of the problem.
However according to both the bug report and how code affected looks like
the problem only triggers for dynamic shared objects to be pulled from
system directories, such as /lib or /usr/lib (assuming the usual system
prefix), and I gather any further ones listed in /etc/ld.so.conf. These
are only populated at the install stage and therefore not relevant for
Furthermore the bug report explicitly refers to the setting of
LD_LIBRARY_PATH as a workaround for the problem, so such an arrangement
obviously cannot be used to trigger the bug. So while code to trigger the
problem can be easily made and run standalone, we currently have no
provisions available to integrate it into our test suite.
There was a discussion at the Glibc BOF at this year's GNU Tools Cauldron
as to how to make the testing of libraries possible in cases where the
root privilege or operation in a fully installed environment would
normally be required to cover a problem being concerned, however at this
point we are quite far from getting there I believe.
Have I missed anything?