IABSD.fr/src/lib/libelf/elf_next.c

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• Author : jsg
  Date : 2019-03-19 02:31:35
  Hash : e219834f
  Message : update libelf from elftoolchain r3669 to r3714 includes changes to address problems sunil@ found with fuzzing original diff from and ok sunil@

• lib/libelf/elf_next.c

• /*-
   * Copyright (c) 2006,2008 Joseph Koshy
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   */
  
  #include <ar.h>
  #include <assert.h>
  #include <libelf.h>
  
  #include "_libelf.h"
  
  ELFTC_VCSID("$Id: elf_next.c,v 1.2 2019/03/19 02:31:35 jsg Exp $");
  
  Elf_Cmd
  elf_next(Elf *e)
  {
  	off_t next;
  	Elf *parent;
  
  	if (e == NULL)
  		return (ELF_C_NULL);
  
  	 if ((parent = e->e_parent) == NULL) {
  		 LIBELF_SET_ERROR(ARGUMENT, 0);
  		 return (ELF_C_NULL);
  	 }
  
  	assert(parent->e_kind == ELF_K_AR);
  	assert(parent->e_cmd == ELF_C_READ);
  	assert(e->e_rawfile > parent->e_rawfile);
  
  	next = e->e_rawfile - parent->e_rawfile + (off_t) e->e_rawsize;
  	next = (next + 1) & ~1;	/* round up to an even boundary */
  
  	/*
  	 * Setup the 'e_next' field of the archive descriptor for the
  	 * next call to 'elf_begin()'.
  	 */
  	parent->e_u.e_ar.e_next = (next >= (off_t) parent->e_rawsize) ?
  	    (off_t) 0 : next;
  
  	/*
  	 * Return an error if the 'e_next' field falls outside the current
  	 * file.
  	 *
  	 * This check is performed after updating the parent descriptor's
  	 * 'e_next' field so that the next call to elf_begin(3) will terminate
  	 * traversal of a too-small archive even if client code forgets to
  	 * check the return value from elf_next(3).
  	 */
  	if (next > (off_t) parent->e_rawsize) {
  		LIBELF_SET_ERROR(ARGUMENT, 0);
  		return (ELF_C_NULL);
  	}
  
  	return (ELF_C_READ);
  }