glibc/dlfcn/dladdr.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

45 lines
1.3 KiB
C

/* Locate the shared object symbol nearest a given address.
Copyright (C) 1996-2017 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
dladdr (const void *address, Dl_info *info)
{
return __dladdr (address, info);
}
#else
int
__dladdr (const void *address, Dl_info *info)
{
# ifdef SHARED
if (!rtld_active ())
return _dlfcn_hook->dladdr (address, info);
# endif
return _dl_addr (address, info, NULL, NULL);
}
# ifdef SHARED
strong_alias (__dladdr, dladdr)
# endif
#endif