1*a1b5ec25Sjsg /*-
2*a1b5ec25Sjsg * Copyright (c) 2006,2008 Joseph Koshy
3*a1b5ec25Sjsg * All rights reserved.
4*a1b5ec25Sjsg *
5*a1b5ec25Sjsg * Redistribution and use in source and binary forms, with or without
6*a1b5ec25Sjsg * modification, are permitted provided that the following conditions
7*a1b5ec25Sjsg * are met:
8*a1b5ec25Sjsg * 1. Redistributions of source code must retain the above copyright
9*a1b5ec25Sjsg * notice, this list of conditions and the following disclaimer.
10*a1b5ec25Sjsg * 2. Redistributions in binary form must reproduce the above copyright
11*a1b5ec25Sjsg * notice, this list of conditions and the following disclaimer in the
12*a1b5ec25Sjsg * documentation and/or other materials provided with the distribution.
13*a1b5ec25Sjsg *
14*a1b5ec25Sjsg * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15*a1b5ec25Sjsg * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16*a1b5ec25Sjsg * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17*a1b5ec25Sjsg * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18*a1b5ec25Sjsg * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19*a1b5ec25Sjsg * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20*a1b5ec25Sjsg * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21*a1b5ec25Sjsg * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22*a1b5ec25Sjsg * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23*a1b5ec25Sjsg * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24*a1b5ec25Sjsg * SUCH DAMAGE.
25*a1b5ec25Sjsg */
26*a1b5ec25Sjsg
27*a1b5ec25Sjsg #include <gelf.h>
28*a1b5ec25Sjsg
29*a1b5ec25Sjsg #include "_libelf.h"
30*a1b5ec25Sjsg
31*a1b5ec25Sjsg ELFTC_VCSID("$Id: libelf_checksum.c,v 1.1 2019/02/01 05:27:38 jsg Exp $");
32*a1b5ec25Sjsg
33*a1b5ec25Sjsg static unsigned long
_libelf_sum(unsigned long c,const unsigned char * s,size_t size)34*a1b5ec25Sjsg _libelf_sum(unsigned long c, const unsigned char *s, size_t size)
35*a1b5ec25Sjsg {
36*a1b5ec25Sjsg if (s == NULL || size == 0)
37*a1b5ec25Sjsg return (c);
38*a1b5ec25Sjsg
39*a1b5ec25Sjsg while (size--)
40*a1b5ec25Sjsg c += *s++;
41*a1b5ec25Sjsg
42*a1b5ec25Sjsg return (c);
43*a1b5ec25Sjsg }
44*a1b5ec25Sjsg
45*a1b5ec25Sjsg long
_libelf_checksum(Elf * e,int elfclass)46*a1b5ec25Sjsg _libelf_checksum(Elf *e, int elfclass)
47*a1b5ec25Sjsg {
48*a1b5ec25Sjsg size_t shn;
49*a1b5ec25Sjsg Elf_Scn *scn;
50*a1b5ec25Sjsg Elf_Data *d;
51*a1b5ec25Sjsg unsigned long checksum;
52*a1b5ec25Sjsg GElf_Ehdr eh;
53*a1b5ec25Sjsg GElf_Shdr shdr;
54*a1b5ec25Sjsg
55*a1b5ec25Sjsg if (e == NULL) {
56*a1b5ec25Sjsg LIBELF_SET_ERROR(ARGUMENT, 0);
57*a1b5ec25Sjsg return (0L);
58*a1b5ec25Sjsg }
59*a1b5ec25Sjsg
60*a1b5ec25Sjsg if (e->e_class != elfclass) {
61*a1b5ec25Sjsg LIBELF_SET_ERROR(CLASS, 0);
62*a1b5ec25Sjsg return (0L);
63*a1b5ec25Sjsg }
64*a1b5ec25Sjsg
65*a1b5ec25Sjsg if (gelf_getehdr(e, &eh) == NULL)
66*a1b5ec25Sjsg return (0);
67*a1b5ec25Sjsg
68*a1b5ec25Sjsg /*
69*a1b5ec25Sjsg * Iterate over all sections in the ELF file, computing the
70*a1b5ec25Sjsg * checksum along the way.
71*a1b5ec25Sjsg *
72*a1b5ec25Sjsg * The first section is always SHN_UNDEF and can be skipped.
73*a1b5ec25Sjsg * Non-allocatable sections are skipped, as are sections that
74*a1b5ec25Sjsg * could be affected by utilities such as strip(1).
75*a1b5ec25Sjsg */
76*a1b5ec25Sjsg
77*a1b5ec25Sjsg checksum = 0;
78*a1b5ec25Sjsg for (shn = 1; shn < e->e_u.e_elf.e_nscn; shn++) {
79*a1b5ec25Sjsg if ((scn = elf_getscn(e, shn)) == NULL)
80*a1b5ec25Sjsg return (0);
81*a1b5ec25Sjsg if (gelf_getshdr(scn, &shdr) == NULL)
82*a1b5ec25Sjsg return (0);
83*a1b5ec25Sjsg if ((shdr.sh_flags & SHF_ALLOC) == 0 ||
84*a1b5ec25Sjsg shdr.sh_type == SHT_DYNAMIC ||
85*a1b5ec25Sjsg shdr.sh_type == SHT_DYNSYM)
86*a1b5ec25Sjsg continue;
87*a1b5ec25Sjsg
88*a1b5ec25Sjsg d = NULL;
89*a1b5ec25Sjsg while ((d = elf_rawdata(scn, d)) != NULL)
90*a1b5ec25Sjsg checksum = _libelf_sum(checksum,
91*a1b5ec25Sjsg (unsigned char *) d->d_buf, (size_t) d->d_size);
92*a1b5ec25Sjsg }
93*a1b5ec25Sjsg
94*a1b5ec25Sjsg /*
95*a1b5ec25Sjsg * Return a 16-bit checksum compatible with Solaris.
96*a1b5ec25Sjsg */
97*a1b5ec25Sjsg return (long) (((checksum >> 16) & 0xFFFFUL) + (checksum & 0xFFFFUL));
98*a1b5ec25Sjsg }
99