1240616Sjimharris/*- 2240616Sjimharris * Copyright (c) 2006,2008 Joseph Koshy 3240616Sjimharris * All rights reserved. 4240616Sjimharris * 5240616Sjimharris * Redistribution and use in source and binary forms, with or without 6240616Sjimharris * modification, are permitted provided that the following conditions 7240616Sjimharris * are met: 8240616Sjimharris * 1. Redistributions of source code must retain the above copyright 9240616Sjimharris * notice, this list of conditions and the following disclaimer. 10240616Sjimharris * 2. Redistributions in binary form must reproduce the above copyright 11240616Sjimharris * notice, this list of conditions and the following disclaimer in the 12240616Sjimharris * documentation and/or other materials provided with the distribution. 13240616Sjimharris * 14240616Sjimharris * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15240616Sjimharris * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16240616Sjimharris * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17240616Sjimharris * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18240616Sjimharris * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19240616Sjimharris * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20240616Sjimharris * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21240616Sjimharris * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22240616Sjimharris * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23240616Sjimharris * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24240616Sjimharris * SUCH DAMAGE. 25240616Sjimharris */ 26240616Sjimharris 27240616Sjimharris#include <gelf.h> 28240616Sjimharris 29240616Sjimharris#include "_libelf.h" 30240616Sjimharris 31240616SjimharrisELFTC_VCSID("$Id: libelf_checksum.c 3174 2015-03-27 17:13:41Z emaste $"); 32240616Sjimharris 33240616Sjimharrisstatic unsigned long 34240616Sjimharris_libelf_sum(unsigned long c, const unsigned char *s, size_t size) 35240616Sjimharris{ 36240616Sjimharris if (s == NULL || size == 0) 37240616Sjimharris return (c); 38240616Sjimharris 39240616Sjimharris while (size--) 40240616Sjimharris c += *s++; 41240616Sjimharris 42240616Sjimharris return (c); 43240616Sjimharris} 44240616Sjimharris 45240616Sjimharrislong 46240616Sjimharris_libelf_checksum(Elf *e, int elfclass) 47240616Sjimharris{ 48240616Sjimharris size_t shn; 49240616Sjimharris Elf_Scn *scn; 50240616Sjimharris Elf_Data *d; 51240616Sjimharris unsigned long checksum; 52240616Sjimharris GElf_Ehdr eh; 53240616Sjimharris GElf_Shdr shdr; 54240616Sjimharris 55240616Sjimharris if (e == NULL) { 56240616Sjimharris LIBELF_SET_ERROR(ARGUMENT, 0); 57240616Sjimharris return (0L); 58240616Sjimharris } 59240616Sjimharris 60240616Sjimharris if (e->e_class != elfclass) { 61240616Sjimharris LIBELF_SET_ERROR(CLASS, 0); 62240616Sjimharris return (0L); 63240616Sjimharris } 64240616Sjimharris 65240616Sjimharris if (gelf_getehdr(e, &eh) == NULL) 66240616Sjimharris return (0); 67240616Sjimharris 68240616Sjimharris /* 69240616Sjimharris * Iterate over all sections in the ELF file, computing the 70240616Sjimharris * checksum along the way. 71240616Sjimharris * 72240616Sjimharris * The first section is always SHN_UNDEF and can be skipped. 73240616Sjimharris * Non-allocatable sections are skipped, as are sections that 74240616Sjimharris * could be affected by utilities such as strip(1). 75240616Sjimharris */ 76240616Sjimharris 77240616Sjimharris checksum = 0; 78240616Sjimharris for (shn = 1; shn < e->e_u.e_elf.e_nscn; shn++) { 79240616Sjimharris if ((scn = elf_getscn(e, shn)) == NULL) 80240616Sjimharris return (0); 81240616Sjimharris if (gelf_getshdr(scn, &shdr) == NULL) 82240616Sjimharris return (0); 83240616Sjimharris if ((shdr.sh_flags & SHF_ALLOC) == 0 || 84240616Sjimharris shdr.sh_type == SHT_DYNAMIC || 85240616Sjimharris shdr.sh_type == SHT_DYNSYM) 86240616Sjimharris continue; 87240616Sjimharris 88240616Sjimharris d = NULL; 89240616Sjimharris while ((d = elf_rawdata(scn, d)) != NULL) 90240616Sjimharris checksum = _libelf_sum(checksum, 91240616Sjimharris (unsigned char *) d->d_buf, (size_t) d->d_size); 92240616Sjimharris } 93240616Sjimharris 94240616Sjimharris /* 95240616Sjimharris * Return a 16-bit checksum compatible with Solaris. 96240616Sjimharris */ 97240616Sjimharris return (long) (((checksum >> 16) & 0xFFFFUL) + (checksum & 0xFFFFUL)); 98240616Sjimharris} 99240616Sjimharris