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       1                 :             : /* Return size of GNU compressed section.
       2                 :             :    Copyright (C) 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 "libdwelfP.h"
      34                 :             : #include "libelfP.h"
      35                 :             : 
      36                 :             : ssize_t
      37                 :          72 : dwelf_scn_gnu_compressed_size (Elf_Scn *scn)
      38                 :             : {
      39         [ -  + ]:          72 :   if (scn == NULL)
      40                 :             :     return -1;
      41                 :             : 
      42                 :          72 :   GElf_Shdr shdr;
      43         [ -  + ]:          72 :   if (gelf_getshdr (scn, &shdr) == NULL)
      44                 :             :     return -1;
      45                 :             : 
      46                 :             :   /* Allocated or no bits sections can never be compressed.  */
      47         [ -  + ]:          72 :   if ((shdr.sh_flags & SHF_ALLOC) != 0
      48         [ -  + ]:          72 :       || shdr.sh_type == SHT_NULL
      49         [ -  + ]:          72 :       || shdr.sh_type == SHT_NOBITS)
      50                 :             :     return -1;
      51                 :             : 
      52                 :          72 :   Elf_Data *d = elf_rawdata (scn, NULL);
      53         [ -  + ]:          72 :   if (d == NULL)
      54                 :             :     return -1;
      55                 :             : 
      56         [ -  + ]:          72 :   if (d->d_size >= 4 + 8
      57         [ -  + ]:          72 :       && memcmp (d->d_buf, "ZLIB", 4) == 0)
      58                 :             :     {
      59                 :             :       /* There is a 12-byte header of "ZLIB" followed by
      60                 :             :          an 8-byte big-endian size.  There is only one type and
      61                 :             :          alignment isn't preserved separately.  */
      62                 :          72 :       uint64_t size;
      63         [ +  - ]:          72 :       memcpy (&size, d->d_buf + 4, sizeof size);
      64         [ +  - ]:          72 :       size = be64toh (size);
      65                 :             : 
      66                 :             :       /* One more sanity check, size should be bigger than original
      67                 :             :          data size plus some overhead (4 chars ZLIB + 8 bytes size + 6
      68                 :             :          bytes zlib stream overhead + 5 bytes overhead max for one 16K
      69                 :             :          block) and should fit into a size_t.  */
      70         [ +  - ]:          72 :       if (size + 4 + 8 + 6 + 5 < d->d_size || size > SIZE_MAX)
      71                 :             :         return -1;
      72                 :             : 
      73                 :          72 :       return size;
      74                 :             :     }
      75                 :             : 
      76                 :             :   return -1;
      77                 :             : }