/*-
* SPDX-License-Identifier: BSD-3-Clause
*
* Copyright (c) 2000, 2001 David O'Brien
* Copyright (c) 1996 Søren Schmidt
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer
* in this position and unchanged.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/cdefs.h>
#include <sys/param.h>
#include <sys/capsicum.h>
#include <sys/elf_common.h>
#include <sys/errno.h>
#include <capsicum_helpers.h>
#include <err.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <libcasper.h>
#include <casper/cap_fileargs.h>
static int elftype(const char *);
static const char *iselftype(int);
static void printelftypes(void);
static void usage(void) __dead2;
struct ELFtypes {
const char *str;
int value;
};
/* XXX - any more types? */
static struct ELFtypes elftypes[] = {
{ "FreeBSD", ELFOSABI_FREEBSD },
{ "Linux", ELFOSABI_LINUX },
{ "Solaris", ELFOSABI_SOLARIS },
{ "SVR4", ELFOSABI_SYSV }
};
int
main(int argc, char **argv)
{
const char *strtype = "FreeBSD";
int ch, flags, retval, type;
bool change, force, listed;
fileargs_t *fa;
cap_rights_t rights;
type = ELFOSABI_FREEBSD;
retval = 0;
change = false;
force = false;
listed = false;
while ((ch = getopt(argc, argv, "f:lt:v")) != -1)
switch (ch) {
case 'f':
if (change)
errx(1, "f option incompatible with t option");
force = true;
type = atoi(optarg);
if (errno == ERANGE || type < 0 || type > 255) {
warnx("invalid argument to option f: %s",
optarg);
usage();
}
break;
case 'l':
printelftypes();
listed = true;
break;
case 'v':
/* does nothing */
break;
case 't':
if (force)
errx(1, "t option incompatible with f option");
change = true;
strtype = optarg;
break;
default:
usage();
}
argc -= optind;
argv += optind;
if (argc == 0) {
if (listed)
exit(0);
else {
warnx("no file(s) specified");
usage();
}
}
if (!force && (type = elftype(strtype)) == -1) {
warnx("invalid ELF type '%s'", strtype);
printelftypes();
usage();
}
flags = change || force ? O_RDWR : O_RDONLY;
cap_rights_init(&rights, CAP_READ, CAP_SEEK);
if (flags == O_RDWR)
cap_rights_set(&rights, CAP_WRITE);
fa = fileargs_init(argc, argv, flags, 0, &rights, FA_OPEN);
if (fa == NULL)
err(1, "unable to init casper");
caph_cache_catpages();
if (caph_limit_stdio() < 0 || caph_enter_casper() < 0)
err(1, "unable to enter capability mode");
while (argc != 0) {
int fd;
char buffer[EI_NIDENT];
if ((fd = fileargs_open(fa, argv[0])) < 0) {
warn("error opening file %s", argv[0]);
retval = 1;
goto fail;
}
if (read(fd, buffer, EI_NIDENT) < EI_NIDENT) {
warnx("file '%s' too short", argv[0]);
retval = 1;
goto fail;
}
if (buffer[0] != ELFMAG0 || buffer[1] != ELFMAG1 ||
buffer[2] != ELFMAG2 || buffer[3] != ELFMAG3) {
warnx("file '%s' is not ELF format", argv[0]);
retval = 1;
goto fail;
}
if (!change && !force) {
fprintf(stdout,
"File '%s' is of brand '%s' (%u).\n",
argv[0], iselftype(buffer[EI_OSABI]),
buffer[EI_OSABI]);
if (!iselftype(type)) {
warnx("ELF ABI Brand '%u' is unknown",
type);
printelftypes();
}
}
else {
buffer[EI_OSABI] = type;
lseek(fd, 0, SEEK_SET);
if (write(fd, buffer, EI_NIDENT) != EI_NIDENT) {
warn("error writing %s %d", argv[0], fd);
retval = 1;
goto fail;
}
}
fail:
close(fd);
argc--;
argv++;
}
fileargs_free(fa);
return (retval);
}
static void
usage(void)
{
(void)fprintf(stderr,
"usage: brandelf [-lv] [-f ELF_ABI_number] [-t string] file ...\n");
exit(1);
}
static const char *
iselftype(int etype)
{
size_t elfwalk;
for (elfwalk = 0; elfwalk < nitems(elftypes); elfwalk++)
if (etype == elftypes[elfwalk].value)
return (elftypes[elfwalk].str);
return (0);
}
static int
elftype(const char *elfstrtype)
{
size_t elfwalk;
for (elfwalk = 0; elfwalk < nitems(elftypes); elfwalk++)
if (strcasecmp(elfstrtype, elftypes[elfwalk].str) == 0)
return (elftypes[elfwalk].value);
return (-1);
}
static void
printelftypes(void)
{
size_t elfwalk;
fprintf(stderr, "known ELF types are: ");
for (elfwalk = 0; elfwalk < nitems(elftypes); elfwalk++)
fprintf(stderr, "%s(%u) ", elftypes[elfwalk].str,
elftypes[elfwalk].value);
fprintf(stderr, "\n");
}
plain