1 /*-
2 * Copyright (c) 2006,2008 Joseph Koshy
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27 #include <ar.h>
28 #include <libelf.h>
29 #include <stdint.h>
30
31 #include "_libelf.h"
32
33 ELFTC_VCSID("$Id: elf_rand.c,v 1.3 2019/03/19 02:37:46 jsg Exp $");
34
35 off_t
elf_rand(Elf * ar,off_t offset)36 elf_rand(Elf *ar, off_t offset)
37 {
38 struct ar_hdr *arh;
39 off_t offset_of_member;
40
41 if (ar == NULL || ar->e_kind != ELF_K_AR ||
42 (offset & 1) || offset < SARMAG ||
43 offset >= ar->e_rawsize) {
44 LIBELF_SET_ERROR(ARGUMENT, 0);
45 return 0;
46 }
47
48 offset_of_member = offset + (off_t) sizeof(struct ar_hdr);
49
50 if (offset_of_member <= 0 || /* Numeric overflow. */
51 offset_of_member >= ar->e_rawsize) {
52 LIBELF_SET_ERROR(ARGUMENT, 0);
53 return 0;
54 }
55
56 arh = (struct ar_hdr *) (ar->e_rawfile + offset);
57
58 /* a too simple sanity check */
59 if (arh->ar_fmag[0] != '`' || arh->ar_fmag[1] != '\n') {
60 LIBELF_SET_ERROR(ARCHIVE, 0);
61 return 0;
62 }
63
64 ar->e_u.e_ar.e_next = offset;
65
66 return (offset);
67 }
68