elf/dl-caller.c

   1 /* Check whether caller comes from the right place.
   2    Copyright (C) 2004 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, write to the Free
  17    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  18    02111-1307 USA.  */
  19
  20 #include <assert.h>
  21 #include <ldsodefs.h>
  22 #include <stddef.h>
  23 #include <caller.h>
  24 #include <gnu/lib-names.h>
  25
  26
  27 int
  28 attribute_hidden
  29 _dl_check_caller (const void *caller, enum allowmask mask)
  30 {
  31   static const char expected1[] = LIBC_SO;
  32   static const char expected2[] = LIBDL_SO;
  33 #ifdef LIBPTHREAD_SO
  34   static const char expected3[] = LIBPTHREAD_SO;
  35 #endif
  36   static const char expected4[] = LD_SO;
  37
  38   for (struct link_map *l = GL(dl_loaded); l != NULL; l = l->l_next)
  39     if (caller >= (const void *) l->l_map_start
  40         && caller < (const void *) l->l_text_end)
  41       {
  42         /* The address falls into this DSO's address range.  Check the
  43            name.  */
  44         if ((mask & allow_libc) && strcmp (expected1, l->l_name) == 0)
  45           return 0;
  46         if ((mask & allow_libdl) && strcmp (expected2, l->l_name) == 0)
  47           return 0;
  48 #ifdef LIBPTHREAD_SO
  49         if ((mask & allow_libpthread) && strcmp (expected3, l->l_name) == 0)
  50           return 0;
  51 #endif
  52         if ((mask & allow_ldso) && strcmp (expected4, l->l_name) == 0)
  53           return 0;
  54
  55         struct libname_list *runp = l->l_libname;
  56
  57         while (runp != NULL)
  58           {
  59             if ((mask & allow_libc) && strcmp (expected1, runp->name) == 0)
  60                   return 0;
  61             if ((mask & allow_libdl) && strcmp (expected2, runp->name) == 0)
  62               return 0;
  63 #ifdef LIBPTHREAD_SO
  64             if ((mask & allow_libpthread)
  65                 && strcmp (expected3, runp->name) == 0)
  66               return 0;
  67 #endif
  68             if ((mask & allow_ldso) && strcmp (expected4, runp->name) == 0)
  69               return 0;
  70
  71             runp = runp->next;
  72           }
  73
  74         break;
  75       }
  76
  77   /* Maybe the dynamic linker is not yet on the list.  */
  78   if ((mask & allow_ldso) != 0
  79       && caller >= (const void *) GL(dl_rtld_map).l_map_start
  80       && caller < (const void *) GL(dl_rtld_map).l_text_end)
  81     return 0;
  82
  83   /* No valid caller.  */
  84   return 1;
  85 }