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Hi, I've spent the half night staring at the devilish my_getpwuid and my_getgrgid functions trying to find out a way to avoid actual and future potential buffer overflow problems without breaking existing code. Finally I've found a not intrusive way to do this that surely doesn't break existing code and fixes a couple of problems too. The attached patch: 1) changes the behaviour of my_getpwuid and my_getgrgid to avoid potetntial buffer overflows 2) fixes all occurences of this function calls in tar.c , id.c , ls.c, whoami.c, logger.c, libbb.h. 3) The behaviour of tar, ls and logger is unchanged. 4) The behavior of ps with somewhat longer usernames messing up output is fixed. 5) The only bigger change was the increasing of size of the buffers in id.c to avoid false negatives (unknown user: xxxxxx) with usernames longer than 8 chars. The value i used ( 32 chars ) was taken from the tar header ( see gname and uname). Maybe this buffers can be reduced a bit ( to 16 or whatever ), this is up to you. 6) The increase of size of the binary is not so dramatic: size busybox text data bss dec hex filename 239568 2300 36816 278684 4409c busybox size busybox_fixed text data bss dec hex filename 239616 2300 36816 278732 440cc busybox 7) The behaviour of whoami changed: actually it prints out an username cut down to the size of the buffer. This could be fixed by increasing the size of the buffer as in id.c or avoid the use of my_getpwuid and use getpwuid directly instead. Maybe this colud be also remain unchanged...... Please apply if you think it is ok to do so. The diff applies on today's cvs tarball (2004-08-25). Thanks in advance, Ciao, Tito
205 lines
5.6 KiB
C
205 lines
5.6 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* Mini logger implementation for busybox
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*
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* Copyright (C) 1999-2004 by Erik Andersen <andersen@codepoet.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#include <stdio.h>
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#include <unistd.h>
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#include <sys/types.h>
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#include <fcntl.h>
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#include <ctype.h>
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#include <string.h>
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#include <stdlib.h>
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#include "busybox.h"
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#if !defined CONFIG_SYSLOGD
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#define SYSLOG_NAMES
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#include <sys/syslog.h>
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#else
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#include <sys/syslog.h>
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# ifndef __dietlibc__
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/* We have to do this since the header file defines static
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* structures. Argh.... bad libc, bad, bad...
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*/
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typedef struct _code {
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char *c_name;
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int c_val;
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} CODE;
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extern CODE prioritynames[];
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extern CODE facilitynames[];
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# endif
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#endif
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/* Decode a symbolic name to a numeric value
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* this function is based on code
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* Copyright (c) 1983, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Original copyright notice is retained at the end of this file.
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*/
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static int decode(char *name, CODE * codetab)
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{
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CODE *c;
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if (isdigit(*name))
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return (atoi(name));
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for (c = codetab; c->c_name; c++) {
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if (!strcasecmp(name, c->c_name)) {
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return (c->c_val);
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}
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}
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return (-1);
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}
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/* Decode a symbolic name to a numeric value
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* this function is based on code
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* Copyright (c) 1983, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Original copyright notice is retained at the end of this file.
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*/
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static int pencode(char *s)
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{
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char *save;
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int lev, fac = LOG_USER;
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for (save = s; *s && *s != '.'; ++s);
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if (*s) {
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*s = '\0';
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fac = decode(save, facilitynames);
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if (fac < 0)
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bb_error_msg_and_die("unknown facility name: %s", save);
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*s++ = '.';
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} else {
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s = save;
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}
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lev = decode(s, prioritynames);
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if (lev < 0)
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bb_error_msg_and_die("unknown priority name: %s", save);
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return ((lev & LOG_PRIMASK) | (fac & LOG_FACMASK));
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}
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extern int logger_main(int argc, char **argv)
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{
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int pri = LOG_USER | LOG_NOTICE;
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int option = 0;
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int c, i, opt;
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char buf[1024], name[128];
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/* Fill out the name string early (may be overwritten later) */
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my_getpwuid(name, geteuid(), sizeof(name));
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/* Parse any options */
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while ((opt = getopt(argc, argv, "p:st:")) > 0) {
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switch (opt) {
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case 's':
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option |= LOG_PERROR;
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break;
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case 'p':
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pri = pencode(optarg);
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break;
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case 't':
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safe_strncpy(name, optarg, sizeof(name));
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break;
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default:
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bb_show_usage();
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}
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}
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openlog(name, option, (pri | LOG_FACMASK));
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if (optind == argc) {
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do {
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/* read from stdin */
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i = 0;
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while ((c = getc(stdin)) != EOF && c != '\n' &&
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i < (sizeof(buf)-1)) {
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buf[i++] = c;
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}
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if (i > 0) {
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buf[i++] = '\0';
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syslog(pri, "%s", buf);
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}
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} while (c != EOF);
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} else {
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char *message = NULL;
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int len = argc - optind; /* for the space between the args
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and '\0' */
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opt = len;
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argv += optind;
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for (i = 0; i < opt; i++) {
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len += strlen(*argv);
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message = xrealloc(message, len);
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if(!i)
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message[0] = 0;
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else
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strcat(message, " ");
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strcat(message, *argv);
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argv++;
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}
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syslog(pri, "%s", message);
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}
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closelog();
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return EXIT_SUCCESS;
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}
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/*-
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* Copyright (c) 1983, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This is the original license statement for the decode and pencode functions.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* 3. <BSD Advertising Clause omitted per the July 22, 1999 licensing change
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* ftp://ftp.cs.berkeley.edu/pub/4bsd/README.Impt.License.Change>
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*
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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