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bc56ab1f4a
When audit modules are loaded, ld.so initialization is not yet complete, and rtld_active () returns false even though ld.so is mostly working. Instead, the static dlopen hook is used, but that does not work at all because this is not a static dlopen situation. Commit466c1ea15f("dlfcn: Rework static dlopen hooks") moved the hook pointer into _rtld_global_ro, which means that separate protection is not needed anymore and the hook pointer can be checked directly. The guard for disabling libio vtable hardening in _IO_vtable_check should stay for now. Fixes commit8e1472d2c1("ld.so: Examine GLRO to detect inactive loader [BZ #20204]"). Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org> (cherry picked from commit8dcb6d0af0)
91 lines
2.4 KiB
C
91 lines
2.4 KiB
C
/* Look up a symbol in a shared object loaded by `dlopen'.
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Copyright (C) 1995-2021 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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<https://www.gnu.org/licenses/>. */
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#include <dlfcn.h>
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#include <ldsodefs.h>
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#include <shlib-compat.h>
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#include <stddef.h>
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struct dlsym_args
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{
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/* The arguments to dlsym_doit. */
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void *handle;
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const char *name;
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void *who;
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/* The return value of dlsym_doit. */
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void *sym;
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};
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static void
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dlsym_doit (void *a)
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{
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struct dlsym_args *args = (struct dlsym_args *) a;
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args->sym = _dl_sym (args->handle, args->name, args->who);
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}
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static void *
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dlsym_implementation (void *handle, const char *name, void *dl_caller)
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{
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struct dlsym_args args;
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args.who = dl_caller;
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args.handle = handle;
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args.name = name;
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/* Protect against concurrent loads and unloads. */
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__rtld_lock_lock_recursive (GL(dl_load_lock));
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void *result = (_dlerror_run (dlsym_doit, &args) ? NULL : args.sym);
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__rtld_lock_unlock_recursive (GL(dl_load_lock));
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return result;
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}
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#ifdef SHARED
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void *
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___dlsym (void *handle, const char *name)
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{
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if (GLRO (dl_dlfcn_hook) != NULL)
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return GLRO (dl_dlfcn_hook)->dlsym (handle, name, RETURN_ADDRESS (0));
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else
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return dlsym_implementation (handle, name, RETURN_ADDRESS (0));
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}
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versioned_symbol (libc, ___dlsym, dlsym, GLIBC_2_34);
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# if OTHER_SHLIB_COMPAT (libdl, GLIBC_2_0, GLIBC_2_34)
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compat_symbol (libdl, ___dlsym, dlsym, GLIBC_2_0);
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# endif
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#else /* !SHARED */
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/* Also used with _dlfcn_hook. */
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void *
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__dlsym (void *handle, const char *name, void *dl_caller)
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{
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return dlsym_implementation (handle, name, dl_caller);
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}
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void *
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___dlsym (void *handle, const char *name)
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{
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return __dlsym (handle, name, RETURN_ADDRESS (0));
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}
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weak_alias (___dlsym, dlsym)
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#endif /* !SHARED */
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