1  /* Support for STV_PROTECTED visibility.  Generic version.
       2     Copyright (C) 2021-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #ifndef _DL_PROTECTED_H
      20  #define _DL_PROTECTED_H
      21  
      22  static inline void __attribute__ ((always_inline))
      23  _dl_check_protected_symbol (const char *undef_name,
      24  			    const struct link_map *undef_map,
      25  			    const ElfW(Sym) *ref,
      26  			    const struct link_map *map,
      27  			    int type_class)
      28  {
      29    if (undef_map == NULL || undef_map->l_type != lt_executable)
      30      return;
      31  
      32    if (type_class & ELF_RTYPE_CLASS_COPY)
      33      /* Disallow copy relocations in executable against protected
      34         data symbols in a shared object which needs indirect external
      35         access.  */
      36      _dl_error_printf ("warning: copy relocation against non-copyable "
      37  		      "protected symbol `%s' in `%s'\n",
      38  		      undef_name, map->l_name);
      39    else if ((type_class & ELF_RTYPE_CLASS_PLT) && ref->st_value != 0
      40  	   && ref->st_shndx == SHN_UNDEF)
      41      /* Disallow non-zero symbol values of undefined symbols in
      42         executable, which are used as the function pointer, against
      43         protected function symbols in a shared object with indirect
      44         external access.  */
      45      _dl_error_printf (
      46  	"warning: direct reference to "
      47  	"protected function `%s' in `%s' may break pointer equality\n",
      48  	undef_name, map->l_name);
      49    else
      50      return;
      51  
      52    if (map->l_1_needed & GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS)
      53      _dl_signal_error (
      54  	0, map->l_name, undef_name,
      55  	N_ ("error due to GNU_PROPERTY_1_NEEDED_INDIRECT_EXTERN_ACCESS"));
      56  }
      57  
      58  #endif /* _DL_PROTECTED_H */