660d4fe299
The length of the name returned from the $LOGNAME and $USER can be very long and it was being concatenated to a fixed length buffer with no bounds checking. Fix this problem by limiting the length of the name copied. Additionally, this name is actually used to create a format string to be used in adding log file entries so embedded % characters in the name could confuse *printf(), and embedded whitespace could confuse a log file parser. Handle the former by escaping each % with an additional %, and handle the latter by simply stripping it out. Clean up the code by moving the variable declarations to the top of the function, formatting them to conform with style, and moving intialization elsewhere. Reduce code indentation by returning early in a couple of places. Reported by: Coverity CID: 1006692 Reviewed by: markj (previous version) MFC after: 2 weeks Differential Revision: https://reviews.freebsd.org/D6490
119 lines
3.4 KiB
C
119 lines
3.4 KiB
C
/*-
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* Copyright (C) 1996
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* David L. Nugent. All rights reserved.
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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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* THIS SOFTWARE IS PROVIDED BY DAVID L. NUGENT 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 DAVID L. NUGENT 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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#ifndef lint
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static const char rcsid[] =
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"$FreeBSD$";
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#endif /* not lint */
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#include <ctype.h>
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#include <err.h>
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#include <fcntl.h>
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#include <string.h>
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#include <stdarg.h>
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#include "pw.h"
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static FILE *logfile = NULL;
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void
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pw_log(struct userconf * cnf, int mode, int which, char const * fmt,...)
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{
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va_list argp;
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time_t now;
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const char *cp, *name;
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struct tm *t;
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int fd, i, rlen;
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char nfmt[256], sname[32];
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if (cnf->logfile == NULL || cnf->logfile[0] == '\0') {
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return;
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}
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if (logfile == NULL) {
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/* With umask==0 we need to control file access modes on create */
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fd = open(cnf->logfile, O_WRONLY | O_CREAT | O_APPEND, 0600);
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if (fd == -1) {
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return;
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}
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logfile = fdopen(fd, "a");
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if (logfile == NULL) {
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return;
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}
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}
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if ((name = getenv("LOGNAME")) == NULL &&
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(name = getenv("USER")) == NULL) {
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strcpy(sname, "unknown");
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} else {
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/*
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* Since "name" will be embedded in a printf-like format,
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* we must sanitize it:
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*
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* Limit its length so other information in the message
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* is not truncated
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*
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* Squeeze out embedded whitespace for the benefit of
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* log file parsers
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*
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* Escape embedded % characters with another %
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*/
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for (i = 0, cp = name;
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*cp != '\0' && i < (int)sizeof(sname) - 1; cp++) {
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if (*cp == '%') {
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if (i < (int)sizeof(sname) - 2) {
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sname[i++] = '%';
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sname[i++] = '%';
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} else {
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break;
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}
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} else if (!isspace(*cp)) {
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sname[i++] = *cp;
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} /* else do nothing */
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}
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if (i == 0) {
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strcpy(sname, "unknown");
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} else {
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sname[i] = '\0';
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}
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}
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now = time(NULL);
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t = localtime(&now);
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/* ISO 8601 International Standard Date format */
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strftime(nfmt, sizeof nfmt, "%Y-%m-%d %T ", t);
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rlen = sizeof(nfmt) - strlen(nfmt);
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if (rlen <= 0 || snprintf(nfmt + strlen(nfmt), rlen,
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"[%s:%s%s] %s\n", sname, Which[which], Modes[mode],
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fmt) >= rlen) {
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warnx("log format overflow, user name=%s", sname);
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} else {
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va_start(argp, fmt);
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vfprintf(logfile, nfmt, argp);
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va_end(argp);
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fflush(logfile);
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}
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}
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