Branch data     Line data    Source code

       1                 :            : /* Get note information at the supplied offset.
       2                 :            :    Copyright (C) 2007, 2014, 2015, 2018 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                 :       6204 : gelf_getnote (Elf_Data *data, size_t offset, GElf_Nhdr *result,
      41                 :            :               size_t *name_offset, size_t *desc_offset)
      42                 :            : {
      43         [ -  + ]:       6204 :   if (data == NULL)
      44                 :            :     return 0;
      45                 :            : 
      46         [ -  + ]:       6204 :   if (unlikely (data->d_type != ELF_T_NHDR && data->d_type != ELF_T_NHDR8))
      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                 :       6204 :   assert (sizeof (GElf_Nhdr) == sizeof (Elf32_Nhdr));
      55                 :       6204 :   assert (sizeof (GElf_Nhdr) == sizeof (Elf64_Nhdr));
      56                 :            : 
      57                 :       6204 :   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   [ +  -  +  + ]:       6204 :   if (unlikely (offset > data->d_size
      62                 :            :                 || data->d_size - offset < sizeof (GElf_Nhdr)))
      63                 :            :     {
      64                 :        335 :       __libelf_seterrno (ELF_E_OFFSET_RANGE);
      65                 :        335 :       offset = 0;
      66                 :            :     }
      67                 :            :   else
      68                 :            :     {
      69                 :       5869 :       const GElf_Nhdr *n = data->d_buf + offset;
      70                 :       5869 :       offset += sizeof *n;
      71                 :            : 
      72         [ -  + ]:       5869 :       if (offset > data->d_size)
      73                 :            :         offset = 0;
      74                 :            :       else
      75                 :            :         {
      76                 :            :           /* This is slightly tricky, offset is guaranteed to be 4
      77                 :            :              byte aligned, which is what we need for the name_offset.
      78                 :            :              And normally desc_offset is also 4 byte aligned, but not
      79                 :            :              for GNU Property notes, then it should be 8.  So align
      80                 :            :              the offset, after adding the namesz, and include padding
      81                 :            :              in descsz to get to the end.  */
      82                 :       5869 :           *name_offset = offset;
      83         [ -  + ]:       5869 :           if (n->n_namesz > data->d_size
      84         [ -  + ]:       5869 :               || offset > data->d_size - n->n_namesz)
      85                 :            :             offset = 0;
      86                 :            :           else
      87                 :            :             {
      88                 :       5869 :               offset += n->n_namesz;
      89                 :            :               /* Include padding.  Check below for overflow.  */
      90         [ +  + ]:       5869 :               GElf_Word descsz = (data->d_type == ELF_T_NHDR8
      91                 :        167 :                                   ? NOTE_ALIGN8 (n->n_descsz)
      92                 :       5702 :                                   : NOTE_ALIGN4 (n->n_descsz));
      93                 :            : 
      94         [ +  + ]:       5869 :               if (data->d_type == ELF_T_NHDR8)
      95                 :        167 :                 offset = NOTE_ALIGN8 (offset);
      96                 :            :               else
      97                 :       5702 :                 offset = NOTE_ALIGN4 (offset);
      98                 :            : 
      99   [ -  +  -  +  :       5869 :               if (unlikely (offset > data->d_size
             +  +  -  + ]
     100                 :            :                             || data->d_size - offset < descsz
     101                 :            :                             || (descsz == 0 && n->n_descsz != 0)))
     102                 :            :                 offset = 0;
     103                 :            :               else
     104                 :            :                 {
     105                 :       5869 :                   *desc_offset = offset;
     106                 :       5869 :                   offset += descsz;
     107                 :       5869 :                   *result = *n;
     108                 :            :                 }
     109                 :            :             }
     110                 :            :         }
     111                 :            :     }
     112                 :            : 
     113                 :       6204 :   rwlock_unlock (((Elf_Data_Scn *) data)->s->elf->lock);
     114                 :            : 
     115                 :       6204 :   return offset;
     116                 :            : }