Line data    Source code

       1             : /* Get note information at the supplied offset.
       2             :    Copyright (C) 2007, 2014, 2015 Red Hat, Inc.
       3             :    This file is part of elfutils.
       4             : 
       5             :    This file is free software; you can redistribute it and/or modify
       6             :    it under the terms of either
       7             : 
       8             :      * the GNU Lesser General Public License as published by the Free
       9             :        Software Foundation; either version 3 of the License, or (at
      10             :        your option) any later version
      11             : 
      12             :    or
      13             : 
      14             :      * the GNU General Public License as published by the Free
      15             :        Software Foundation; either version 2 of the License, or (at
      16             :        your option) any later version
      17             : 
      18             :    or both in parallel, as here.
      19             : 
      20             :    elfutils is distributed in the hope that it will be useful, but
      21             :    WITHOUT ANY WARRANTY; without even the implied warranty of
      22             :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      23             :    General Public License for more details.
      24             : 
      25             :    You should have received copies of the GNU General Public License and
      26             :    the GNU Lesser General Public License along with this program.  If
      27             :    not, see <http://www.gnu.org/licenses/>.  */
      28             : 
      29             : #ifdef HAVE_CONFIG_H
      30             : # include <config.h>
      31             : #endif
      32             : 
      33             : #include <assert.h>
      34             : #include <gelf.h>
      35             : #include <string.h>
      36             : 
      37             : #include "libelfP.h"
      38             : 
      39             : size_t
      40        1787 : gelf_getnote (Elf_Data *data, size_t offset, GElf_Nhdr *result,
      41             :               size_t *name_offset, size_t *desc_offset)
      42             : {
      43        1787 :   if (data == NULL)
      44             :     return 0;
      45             : 
      46        1787 :   if (unlikely (data->d_type != ELF_T_NHDR))
      47             :     {
      48           0 :       __libelf_seterrno (ELF_E_INVALID_HANDLE);
      49           0 :       return 0;
      50             :     }
      51             : 
      52             :   /* It's easy to handle this type.  It has the same size for 32 and
      53             :      64 bit objects.  */
      54             :   assert (sizeof (GElf_Nhdr) == sizeof (Elf32_Nhdr));
      55             :   assert (sizeof (GElf_Nhdr) == sizeof (Elf64_Nhdr));
      56             : 
      57             :   rwlock_rdlock (((Elf_Data_Scn *) data)->s->elf->lock);
      58             : 
      59             :   /* The data is already in the correct form.  Just make sure the
      60             :      offset is OK.  */
      61        1787 :   if (unlikely (offset > data->d_size
      62             :                 || data->d_size - offset < sizeof (GElf_Nhdr)))
      63             :     {
      64         146 :       __libelf_seterrno (ELF_E_OFFSET_RANGE);
      65         146 :       offset = 0;
      66             :     }
      67             :   else
      68             :     {
      69        1641 :       const GElf_Nhdr *n = data->d_buf + offset;
      70        1641 :       offset += sizeof *n;
      71             : 
      72             :       /* Include padding.  Check below for overflow.  */
      73        1641 :       GElf_Word namesz = NOTE_ALIGN (n->n_namesz);
      74        1641 :       GElf_Word descsz = NOTE_ALIGN (n->n_descsz);
      75             : 
      76        1641 :       if (unlikely (offset > data->d_size
      77             :                     || data->d_size - offset < namesz
      78             :                     || (namesz == 0 && n->n_namesz != 0)))
      79             :         offset = 0;
      80             :       else
      81             :         {
      82        1641 :           *name_offset = offset;
      83        1641 :           offset += namesz;
      84        1641 :           if (unlikely (offset > data->d_size
      85             :                         || data->d_size - offset < descsz
      86             :                         || (descsz == 0 && n->n_descsz != 0)))
      87             :             offset = 0;
      88             :           else
      89             :             {
      90        1641 :               *desc_offset = offset;
      91        1641 :               offset += descsz;
      92        1641 :               *result = *n;
      93             :             }
      94             :         }
      95             :     }
      96             : 
      97             :   rwlock_unlock (((Elf_Data_Scn *) data)->s->elf->lock);
      98             : 
      99        1787 :   return offset;
     100             : }