Line data    Source code

       1             : /* Return number of program headers in the ELF file.
       2             :    Copyright (C) 2010, 2014, 2015, 2016 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 <stddef.h>
      36             : 
      37             : #include "libelfP.h"
      38             : 
      39             : 
      40             : int
      41             : internal_function
      42       72249 : __elf_getphdrnum_rdlock (Elf *elf, size_t *dst)
      43             : {
      44       72249 :  if (unlikely (elf->state.elf64.ehdr == NULL))
      45             :    {
      46             :      /* Maybe no ELF header was created yet.  */
      47           0 :      __libelf_seterrno (ELF_E_WRONG_ORDER_EHDR);
      48           0 :      return -1;
      49             :    }
      50             : 
      51      144498 :  *dst = (elf->class == ELFCLASS32
      52       14176 :          ? elf->state.elf32.ehdr->e_phnum
      53       72249 :          : elf->state.elf64.ehdr->e_phnum);
      54             : 
      55       72249 :  if (*dst == PN_XNUM)
      56             :    {
      57           6 :      const Elf_ScnList *const scns = (elf->class == ELFCLASS32
      58             :                                       ? &elf->state.elf32.scns
      59             :                                       : &elf->state.elf64.scns);
      60             : 
      61             :      /* If there are no section headers, perhaps this is really just 65536
      62             :         written without PN_XNUM support.  Either that or it's bad data.  */
      63             : 
      64           6 :      if (elf->class == ELFCLASS32)
      65             :        {
      66           0 :          if (likely (scns->cnt > 0))
      67             :            {
      68           0 :              Elf_Scn *scn = &elf->state.elf32.scns.data[0];
      69           0 :              Elf32_Shdr *shdr = scn->shdr.e32 ?: __elf32_getshdr_rdlock (scn);
      70           0 :              if (shdr)
      71           0 :                *dst = shdr->sh_info;
      72             :            }
      73             :        }
      74             :      else
      75             :        {
      76           6 :          if (likely (scns->cnt > 0))
      77             :            {
      78           6 :              Elf_Scn *scn = &elf->state.elf64.scns.data[0];
      79           6 :              Elf64_Shdr *shdr = scn->shdr.e64 ?: __elf64_getshdr_rdlock (scn);
      80           6 :              if (shdr)
      81           6 :                *dst = shdr->sh_info;
      82             :            }
      83             :        }
      84             :    }
      85             : 
      86             :  return 0;
      87             : }
      88             : 
      89             : int
      90             : internal_function
      91       64467 : __elf_getphdrnum_chk_rdlock (Elf *elf, size_t *dst)
      92             : {
      93       64467 :   int result = __elf_getphdrnum_rdlock (elf, dst);
      94             : 
      95             :   /* If the phdrs haven't been created or read in yet then do some
      96             :      sanity checking to make sure phnum and phoff are consistent.  */
      97       64467 :   if (elf->state.elf.phdr == NULL)
      98             :     {
      99       15350 :       Elf64_Off off = (elf->class == ELFCLASS32
     100         773 :                        ? elf->state.elf32.ehdr->e_phoff
     101        7675 :                        : elf->state.elf64.ehdr->e_phoff);
     102        7675 :       if (unlikely (off == 0))
     103             :         {
     104        1236 :           *dst = 0;
     105        1236 :           return result;
     106             :         }
     107             : 
     108        6439 :       if (unlikely (off >= elf->maximum_size))
     109             :         {
     110           0 :           __libelf_seterrno (ELF_E_INVALID_DATA);
     111           0 :           return -1;
     112             :         }
     113             : 
     114             :       /* Check for too many sections.  */
     115       12878 :       size_t phdr_size = (elf->class == ELFCLASS32
     116        6439 :                           ? sizeof (Elf32_Phdr) : sizeof (Elf64_Phdr));
     117        6439 :       if (unlikely (*dst > SIZE_MAX / phdr_size))
     118             :         {
     119           0 :           __libelf_seterrno (ELF_E_INVALID_DATA);
     120           0 :           return -1;
     121             :         }
     122             : 
     123             :       /* Truncated file?  Don't return more than can be indexed.  */
     124        6439 :       if (unlikely (elf->maximum_size - off < *dst * phdr_size))
     125           0 :         *dst = (elf->maximum_size - off) / phdr_size;
     126             :     }
     127             : 
     128             :   return result;
     129             : }
     130             : 
     131             : int
     132        8705 : elf_getphdrnum (Elf *elf, size_t *dst)
     133             : {
     134        8705 :   int result;
     135             : 
     136        8705 :   if (elf == NULL)
     137             :     return -1;
     138             : 
     139        8705 :   if (unlikely (elf->kind != ELF_K_ELF))
     140             :     {
     141           0 :       __libelf_seterrno (ELF_E_INVALID_HANDLE);
     142           0 :       return -1;
     143             :     }
     144             : 
     145        8705 :   rwlock_rdlock (elf->lock);
     146        8705 :   result = __elf_getphdrnum_chk_rdlock (elf, dst);
     147        8705 :   rwlock_unlock (elf->lock);
     148             : 
     149        8705 :   return result;
     150             : }