glibc/dlfcn/dlclose.c
Florian Weimer 8e1472d2c1 ld.so: Examine GLRO to detect inactive loader [BZ #20204]
GLRO (_rtld_global_ro) is read-only after initialization and can
therefore not be patched at run time, unlike the hook table addresses
and their contents, so this is a desirable hardening feature.

The hooks are only needed if ld.so has not been initialized, and this
happens only after static dlopen (dlmopen uses a single ld.so object
across all namespaces).

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2017-12-18 20:04:13 +01:00

52 lines
1.3 KiB
C

/* Close a handle opened by `dlopen'.
Copyright (C) 1995-2017 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <dlfcn.h>
#include <ldsodefs.h>
#if !defined SHARED && IS_IN (libdl)
int
dlclose (void *handle)
{
return __dlclose (handle);
}
#else
static void
dlclose_doit (void *handle)
{
GLRO(dl_close) (handle);
}
int
__dlclose (void *handle)
{
# ifdef SHARED
if (!rtld_active ())
return _dlfcn_hook->dlclose (handle);
# endif
return _dlerror_run (dlclose_doit, handle) ? -1 : 0;
}
# ifdef SHARED
strong_alias (__dlclose, dlclose)
# endif
#endif