[Bug dynamic-link/16871] New: ldconfig -X should not touch symlinks

[Bug dynamic-link/16871] New: ldconfig -X should not touch symlinks

[Martin.vGagern at gmx dot net]

https://sourceware.org/bugzilla/show_bug.cgi?id=16871

            Bug ID: 16871
           Summary: ldconfig -X should not touch symlinks
           Product: glibc
           Version: 2.19
            Status: NEW
          Severity: minor
          Priority: P2
         Component: dynamic-link
          Assignee: unassigned at sourceware dot org
          Reporter: Martin.vGagern at gmx dot net

Currently (and since commit 647eb037f from 2001), ldconfig will unlink any file
it considers a stale library symlink. It will do so even if the -X option is
given on the command line, and it will also do so no matter what error occurred
while executing stat64 on the real file name.

One problem with this is that people might reasonably expect unlink -X -N to
have no side effects except its output. This is how I found the issue: the
configure script of the xapian library calls “/sbin/ldconfig -N -X -v”, and
does so only to parse its output, with no modification intended.

Another problem is that the errno resulting from the stat64 call is not
checked. So any error accessing that file leads to removal of the symlink. In
particular, insufficient permissions are affected by this as well. So if a
group of admins were allowed to write /usr/lib and someone installed a symlink
there to a library which is group-readable but not world-readable, then an
admin not in that group might accidentially delete said symlink. With only root
accessing these directories, access should normally not be a problem, but I
guess the problem might reappear with e.g. nfs mapping root to non-root.

So on the whole, I suggest that you change the unlink condition to
if (errno == ENOENT && do_remove && strstr (direntry->d_name, ".so."))
or something like this.

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Subject: [Bug nptl/15119] [arm] unnecessary busy loop in __lll_timedlock_wait on ARM
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https://sourceware.org/bugzilla/show_bug.cgi?id\x15119

Bernard Ogden <bernie.ogden at linaro dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |bernie.ogden at linaro dot org
           Assignee|maxim.kuvyrkov at gmail dot com    |bernie.ogden at linaro dot org

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[Bug dynamic-link/16871] ldconfig -X should not touch symlinks

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=16871

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |fweimer at redhat dot com

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[Bug dynamic-link/16871] ldconfig -X should not touch symlinks

[vapier at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=16871

Mike Frysinger <vapier at gentoo dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |vapier at gentoo dot org
           See Also|                            |https://bugs.gentoo.org/sho
                   |                            |w_bug.cgi?id=508052

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[Bug dynamic-link/16871] ldconfig -X should not touch symlinks

[fweimer at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=16871

Florian Weimer <fweimer at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
              Flags|                            |security-

--- Comment #1 from Florian Weimer <fweimer at redhat dot com> ---
The incorrect deletion does not really cross a trust boundary, so no security
issue.

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