1*2de3b87aSKai Wang /*- 2*2de3b87aSKai Wang * Copyright (c) 2006,2008 Joseph Koshy 3*2de3b87aSKai Wang * All rights reserved. 4*2de3b87aSKai Wang * 5*2de3b87aSKai Wang * Redistribution and use in source and binary forms, with or without 6*2de3b87aSKai Wang * modification, are permitted provided that the following conditions 7*2de3b87aSKai Wang * are met: 8*2de3b87aSKai Wang * 1. Redistributions of source code must retain the above copyright 9*2de3b87aSKai Wang * notice, this list of conditions and the following disclaimer. 10*2de3b87aSKai Wang * 2. Redistributions in binary form must reproduce the above copyright 11*2de3b87aSKai Wang * notice, this list of conditions and the following disclaimer in the 12*2de3b87aSKai Wang * documentation and/or other materials provided with the distribution. 13*2de3b87aSKai Wang * 14*2de3b87aSKai Wang * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15*2de3b87aSKai Wang * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16*2de3b87aSKai Wang * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17*2de3b87aSKai Wang * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18*2de3b87aSKai Wang * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19*2de3b87aSKai Wang * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20*2de3b87aSKai Wang * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21*2de3b87aSKai Wang * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22*2de3b87aSKai Wang * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23*2de3b87aSKai Wang * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24*2de3b87aSKai Wang * SUCH DAMAGE. 25*2de3b87aSKai Wang */ 26*2de3b87aSKai Wang 27*2de3b87aSKai Wang #include <sys/cdefs.h> 28*2de3b87aSKai Wang 29*2de3b87aSKai Wang #include <gelf.h> 30*2de3b87aSKai Wang 31*2de3b87aSKai Wang #include "_libelf.h" 32*2de3b87aSKai Wang 33*2de3b87aSKai Wang ELFTC_VCSID("$Id: libelf_checksum.c 2225 2011-11-26 18:55:54Z jkoshy $"); 34*2de3b87aSKai Wang 35*2de3b87aSKai Wang static unsigned long 36*2de3b87aSKai Wang _libelf_sum(unsigned long c, const unsigned char *s, size_t size) 37*2de3b87aSKai Wang { 38*2de3b87aSKai Wang if (s == NULL || size == 0) 39*2de3b87aSKai Wang return (c); 40*2de3b87aSKai Wang 41*2de3b87aSKai Wang while (size--) 42*2de3b87aSKai Wang c += *s++; 43*2de3b87aSKai Wang 44*2de3b87aSKai Wang return (c); 45*2de3b87aSKai Wang } 46*2de3b87aSKai Wang 47*2de3b87aSKai Wang unsigned long 48*2de3b87aSKai Wang _libelf_checksum(Elf *e, int elfclass) 49*2de3b87aSKai Wang { 50*2de3b87aSKai Wang size_t shn; 51*2de3b87aSKai Wang Elf_Scn *scn; 52*2de3b87aSKai Wang Elf_Data *d; 53*2de3b87aSKai Wang unsigned long checksum; 54*2de3b87aSKai Wang GElf_Ehdr eh; 55*2de3b87aSKai Wang GElf_Shdr shdr; 56*2de3b87aSKai Wang 57*2de3b87aSKai Wang if (e == NULL) { 58*2de3b87aSKai Wang LIBELF_SET_ERROR(ARGUMENT, 0); 59*2de3b87aSKai Wang return (0L); 60*2de3b87aSKai Wang } 61*2de3b87aSKai Wang 62*2de3b87aSKai Wang if (e->e_class != elfclass) { 63*2de3b87aSKai Wang LIBELF_SET_ERROR(CLASS, 0); 64*2de3b87aSKai Wang return (0L); 65*2de3b87aSKai Wang } 66*2de3b87aSKai Wang 67*2de3b87aSKai Wang if (gelf_getehdr(e, &eh) == NULL) 68*2de3b87aSKai Wang return (0); 69*2de3b87aSKai Wang 70*2de3b87aSKai Wang /* 71*2de3b87aSKai Wang * Iterate over all sections in the ELF file, computing the 72*2de3b87aSKai Wang * checksum along the way. 73*2de3b87aSKai Wang * 74*2de3b87aSKai Wang * The first section is always SHN_UNDEF and can be skipped. 75*2de3b87aSKai Wang * Non-allocatable sections are skipped, as are sections that 76*2de3b87aSKai Wang * could be affected by utilities such as strip(1). 77*2de3b87aSKai Wang */ 78*2de3b87aSKai Wang 79*2de3b87aSKai Wang checksum = 0; 80*2de3b87aSKai Wang for (shn = 1; shn < e->e_u.e_elf.e_nscn; shn++) { 81*2de3b87aSKai Wang if ((scn = elf_getscn(e, shn)) == NULL) 82*2de3b87aSKai Wang return (0); 83*2de3b87aSKai Wang if (gelf_getshdr(scn, &shdr) == NULL) 84*2de3b87aSKai Wang return (0); 85*2de3b87aSKai Wang if ((shdr.sh_flags & SHF_ALLOC) == 0 || 86*2de3b87aSKai Wang shdr.sh_type == SHT_DYNAMIC || 87*2de3b87aSKai Wang shdr.sh_type == SHT_DYNSYM) 88*2de3b87aSKai Wang continue; 89*2de3b87aSKai Wang 90*2de3b87aSKai Wang d = NULL; 91*2de3b87aSKai Wang while ((d = elf_rawdata(scn, d)) != NULL) 92*2de3b87aSKai Wang checksum = _libelf_sum(checksum, 93*2de3b87aSKai Wang (unsigned char *) d->d_buf, d->d_size); 94*2de3b87aSKai Wang } 95*2de3b87aSKai Wang 96*2de3b87aSKai Wang /* 97*2de3b87aSKai Wang * Return a 16-bit checksum compatible with Solaris. 98*2de3b87aSKai Wang */ 99*2de3b87aSKai Wang return (((checksum >> 16) & 0xFFFFUL) + (checksum & 0xFFFFUL)); 100*2de3b87aSKai Wang } 101