1*f8fb3368SJohn Marino /*-
2*f8fb3368SJohn Marino * Copyright (c) 2006,2008 Joseph Koshy
3*f8fb3368SJohn Marino * All rights reserved.
4*f8fb3368SJohn Marino *
5*f8fb3368SJohn Marino * Redistribution and use in source and binary forms, with or without
6*f8fb3368SJohn Marino * modification, are permitted provided that the following conditions
7*f8fb3368SJohn Marino * are met:
8*f8fb3368SJohn Marino * 1. Redistributions of source code must retain the above copyright
9*f8fb3368SJohn Marino * notice, this list of conditions and the following disclaimer.
10*f8fb3368SJohn Marino * 2. Redistributions in binary form must reproduce the above copyright
11*f8fb3368SJohn Marino * notice, this list of conditions and the following disclaimer in the
12*f8fb3368SJohn Marino * documentation and/or other materials provided with the distribution.
13*f8fb3368SJohn Marino *
14*f8fb3368SJohn Marino * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15*f8fb3368SJohn Marino * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16*f8fb3368SJohn Marino * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17*f8fb3368SJohn Marino * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18*f8fb3368SJohn Marino * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19*f8fb3368SJohn Marino * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20*f8fb3368SJohn Marino * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21*f8fb3368SJohn Marino * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22*f8fb3368SJohn Marino * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23*f8fb3368SJohn Marino * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24*f8fb3368SJohn Marino * SUCH DAMAGE.
25*f8fb3368SJohn Marino */
26*f8fb3368SJohn Marino
27*f8fb3368SJohn Marino #include <gelf.h>
28*f8fb3368SJohn Marino
29*f8fb3368SJohn Marino #include "_libelf.h"
30*f8fb3368SJohn Marino
31*f8fb3368SJohn Marino ELFTC_VCSID("$Id: libelf_checksum.c 3174 2015-03-27 17:13:41Z emaste $");
32*f8fb3368SJohn Marino
33*f8fb3368SJohn Marino static unsigned long
_libelf_sum(unsigned long c,const unsigned char * s,size_t size)34*f8fb3368SJohn Marino _libelf_sum(unsigned long c, const unsigned char *s, size_t size)
35*f8fb3368SJohn Marino {
36*f8fb3368SJohn Marino if (s == NULL || size == 0)
37*f8fb3368SJohn Marino return (c);
38*f8fb3368SJohn Marino
39*f8fb3368SJohn Marino while (size--)
40*f8fb3368SJohn Marino c += *s++;
41*f8fb3368SJohn Marino
42*f8fb3368SJohn Marino return (c);
43*f8fb3368SJohn Marino }
44*f8fb3368SJohn Marino
45*f8fb3368SJohn Marino long
_libelf_checksum(Elf * e,int elfclass)46*f8fb3368SJohn Marino _libelf_checksum(Elf *e, int elfclass)
47*f8fb3368SJohn Marino {
48*f8fb3368SJohn Marino size_t shn;
49*f8fb3368SJohn Marino Elf_Scn *scn;
50*f8fb3368SJohn Marino Elf_Data *d;
51*f8fb3368SJohn Marino unsigned long checksum;
52*f8fb3368SJohn Marino GElf_Ehdr eh;
53*f8fb3368SJohn Marino GElf_Shdr shdr;
54*f8fb3368SJohn Marino
55*f8fb3368SJohn Marino if (e == NULL) {
56*f8fb3368SJohn Marino LIBELF_SET_ERROR(ARGUMENT, 0);
57*f8fb3368SJohn Marino return (0L);
58*f8fb3368SJohn Marino }
59*f8fb3368SJohn Marino
60*f8fb3368SJohn Marino if (e->e_class != elfclass) {
61*f8fb3368SJohn Marino LIBELF_SET_ERROR(CLASS, 0);
62*f8fb3368SJohn Marino return (0L);
63*f8fb3368SJohn Marino }
64*f8fb3368SJohn Marino
65*f8fb3368SJohn Marino if (gelf_getehdr(e, &eh) == NULL)
66*f8fb3368SJohn Marino return (0);
67*f8fb3368SJohn Marino
68*f8fb3368SJohn Marino /*
69*f8fb3368SJohn Marino * Iterate over all sections in the ELF file, computing the
70*f8fb3368SJohn Marino * checksum along the way.
71*f8fb3368SJohn Marino *
72*f8fb3368SJohn Marino * The first section is always SHN_UNDEF and can be skipped.
73*f8fb3368SJohn Marino * Non-allocatable sections are skipped, as are sections that
74*f8fb3368SJohn Marino * could be affected by utilities such as strip(1).
75*f8fb3368SJohn Marino */
76*f8fb3368SJohn Marino
77*f8fb3368SJohn Marino checksum = 0;
78*f8fb3368SJohn Marino for (shn = 1; shn < e->e_u.e_elf.e_nscn; shn++) {
79*f8fb3368SJohn Marino if ((scn = elf_getscn(e, shn)) == NULL)
80*f8fb3368SJohn Marino return (0);
81*f8fb3368SJohn Marino if (gelf_getshdr(scn, &shdr) == NULL)
82*f8fb3368SJohn Marino return (0);
83*f8fb3368SJohn Marino if ((shdr.sh_flags & SHF_ALLOC) == 0 ||
84*f8fb3368SJohn Marino shdr.sh_type == SHT_DYNAMIC ||
85*f8fb3368SJohn Marino shdr.sh_type == SHT_DYNSYM)
86*f8fb3368SJohn Marino continue;
87*f8fb3368SJohn Marino
88*f8fb3368SJohn Marino d = NULL;
89*f8fb3368SJohn Marino while ((d = elf_rawdata(scn, d)) != NULL)
90*f8fb3368SJohn Marino checksum = _libelf_sum(checksum,
91*f8fb3368SJohn Marino (unsigned char *) d->d_buf, (size_t) d->d_size);
92*f8fb3368SJohn Marino }
93*f8fb3368SJohn Marino
94*f8fb3368SJohn Marino /*
95*f8fb3368SJohn Marino * Return a 16-bit checksum compatible with Solaris.
96*f8fb3368SJohn Marino */
97*f8fb3368SJohn Marino return (long) (((checksum >> 16) & 0xFFFFUL) + (checksum & 0xFFFFUL));
98*f8fb3368SJohn Marino }
99