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8e1472d2c1
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>
127 lines
3.0 KiB
C
127 lines
3.0 KiB
C
/* dlinfo -- Get information from the dynamic linker.
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Copyright (C) 2003-2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <dlfcn.h>
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#include <link.h>
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#include <ldsodefs.h>
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#include <libintl.h>
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#if !defined SHARED && IS_IN (libdl)
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int
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dlinfo (void *handle, int request, void *arg)
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{
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return __dlinfo (handle, request, arg, RETURN_ADDRESS (0));
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}
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#else
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# include <dl-tls.h>
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struct dlinfo_args
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{
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ElfW(Addr) caller;
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void *handle;
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int request;
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void *arg;
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};
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static void
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dlinfo_doit (void *argsblock)
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{
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struct dlinfo_args *const args = argsblock;
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struct link_map *l = args->handle;
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# if 0
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if (args->handle == RTLD_SELF)
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{
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Lmid_t nsid;
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/* Find the highest-addressed object that CALLER is not below. */
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for (nsid = 0; nsid < DL_NNS; ++nsid)
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for (l = GL(dl_ns)[nsid]._ns_loaded; l != NULL; l = l->l_next)
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if (caller >= l->l_map_start && caller < l->l_map_end
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&& (l->l_contiguous || _dl_addr_inside_object (l, caller)))
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break;
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if (l == NULL)
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_dl_signal_error (0, NULL, NULL, N_("\
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RTLD_SELF used in code not dynamically loaded"));
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}
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# endif
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switch (args->request)
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{
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case RTLD_DI_CONFIGADDR:
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default:
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_dl_signal_error (0, NULL, NULL, N_("unsupported dlinfo request"));
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break;
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case RTLD_DI_LMID:
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*(Lmid_t *) args->arg = l->l_ns;
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break;
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case RTLD_DI_LINKMAP:
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*(struct link_map **) args->arg = l;
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break;
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case RTLD_DI_SERINFO:
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_dl_rtld_di_serinfo (l, args->arg, false);
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break;
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case RTLD_DI_SERINFOSIZE:
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_dl_rtld_di_serinfo (l, args->arg, true);
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break;
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case RTLD_DI_ORIGIN:
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strcpy (args->arg, l->l_origin);
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break;
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case RTLD_DI_TLS_MODID:
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*(size_t *) args->arg = 0;
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*(size_t *) args->arg = l->l_tls_modid;
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break;
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case RTLD_DI_TLS_DATA:
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{
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void *data = NULL;
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if (l->l_tls_modid != 0)
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data = GLRO(dl_tls_get_addr_soft) (l);
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*(void **) args->arg = data;
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break;
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}
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}
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}
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int
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__dlinfo (void *handle, int request, void *arg DL_CALLER_DECL)
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{
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# ifdef SHARED
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if (!rtld_active ())
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return _dlfcn_hook->dlinfo (handle, request, arg,
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DL_CALLER);
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# endif
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struct dlinfo_args args = { (ElfW(Addr)) DL_CALLER,
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handle, request, arg };
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return _dlerror_run (&dlinfo_doit, &args) ? -1 : 0;
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}
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# ifdef SHARED
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strong_alias (__dlinfo, dlinfo)
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# endif
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#endif
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