1 /* $NetBSD: elf_rand.c,v 1.5 2024/03/03 17:37:33 christos Exp $ */
2
3 /*-
4 * Copyright (c) 2006,2008 Joseph Koshy
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30
31 #include <ar.h>
32 #include <libelf.h>
33
34 #include "_libelf.h"
35
36 __RCSID("$NetBSD: elf_rand.c,v 1.5 2024/03/03 17:37:33 christos Exp $");
37
38 off_t
elf_rand(Elf * ar,off_t offset)39 elf_rand(Elf *ar, off_t offset)
40 {
41 struct ar_hdr *arh;
42 off_t offset_of_member;
43
44 if (ar == NULL || ar->e_kind != ELF_K_AR ||
45 (offset & 1) || offset < SARMAG ||
46 offset >= ar->e_rawsize) {
47 LIBELF_SET_ERROR(ARGUMENT, 0);
48 return 0;
49 }
50
51 offset_of_member = offset + (off_t) sizeof(struct ar_hdr);
52
53 if (offset_of_member <= 0 || /* Numeric overflow. */
54 offset_of_member >= ar->e_rawsize) {
55 LIBELF_SET_ERROR(ARGUMENT, 0);
56 return 0;
57 }
58
59 arh = (struct ar_hdr *) (ar->e_rawfile + offset);
60
61 /* a too simple sanity check */
62 if (arh->ar_fmag[0] != '`' || arh->ar_fmag[1] != '\n') {
63 LIBELF_SET_ERROR(ARCHIVE, 0);
64 return 0;
65 }
66
67 ar->e_u.e_ar.e_next = offset;
68
69 return (offset);
70 }
71