e0ee807b3d
last night: _gr_breakout_yp() doesn't check for badly formatted NIS group entries. For example, a bogus entry like this: bootp::user1,user2,user3 will lead to a null pointer dereference and a SEGV (note that the GID field is missing -- this results in one of the strsep(&result, ":") returning NULL). The symtpom of this problem is programs dumping core left and right the moment you add a + entry to /etc/group. Note that while this is similar to an earlier bug, it's caused by a different set of circumstances. The fix is to check for the NULL pointers and have _gr_breakout_yp() punt and return a failure code if it catches one. This is more or less the behavior of SunOS: if a bad NIS group entry is encountered, it's silently ignored. I don't think our standard (non-NIS) group parsing code behaves the same way. It doesn't crash though, so I'm citing the 'it ain't broken, don't fix it' rule and leaving it alone. I'll probably have to add similar checks to _pw_breakout_yp() in getpwent.c to ward off the same problems. It's rare that bad NIS map entries like this occur, but we should handle them gracefully when they do.
412 lines
8.6 KiB
C
412 lines
8.6 KiB
C
/*
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* Copyright (c) 1989, 1993
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* The Regents of the University of California. 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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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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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#if defined(LIBC_SCCS) && !defined(lint)
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static char sccsid[] = "@(#)getgrent.c 8.2 (Berkeley) 3/21/94";
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#endif /* LIBC_SCCS and not lint */
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#include <sys/types.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <grp.h>
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static FILE *_gr_fp;
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static struct group _gr_group;
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static int _gr_stayopen;
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static int grscan(), start_gr();
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#ifdef YP
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#include <rpc/rpc.h>
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#include <rpcsvc/yp_prot.h>
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#include <rpcsvc/ypclnt.h>
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static int _gr_stepping_yp;
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static int _gr_yp_enabled;
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static int _getypgroup(struct group *, const char *, char *);
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static int _nextypgroup(struct group *);
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#endif
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#define MAXGRP 200
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static char *members[MAXGRP];
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#define MAXLINELENGTH 1024
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static char line[MAXLINELENGTH];
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struct group *
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getgrent()
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{
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if (!_gr_fp && !start_gr()) {
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return NULL;
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}
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#ifdef YP
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if (_gr_stepping_yp) {
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return (_nextypgroup(&_gr_group) ? &_gr_group : 0);
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}
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#endif
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if (!grscan(0, 0, NULL))
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return(NULL);
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#ifdef YP
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if(_gr_group.gr_name[0] == '+' && _gr_group.gr_name[1]) {
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_getypgroup(&_gr_group, &_gr_group.gr_name[1],
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"group.byname");
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} else if(_gr_group.gr_name[0] == '+') {
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return (_nextypgroup(&_gr_group) ? &_gr_group : 0);
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}
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#endif
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return(&_gr_group);
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}
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struct group *
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getgrnam(name)
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const char *name;
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{
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int rval;
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if (!start_gr())
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return(NULL);
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rval = grscan(1, 0, name);
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#ifdef YP
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if(!rval && (_gr_yp_enabled < 0 || (_gr_yp_enabled &&
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_gr_group.gr_name[0] == '+'))) {
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rval = _getypgroup(&_gr_group, name, "group.byname");
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}
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#endif
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if (!_gr_stayopen)
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endgrent();
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return(rval ? &_gr_group : NULL);
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}
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struct group *
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#ifdef __STDC__
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getgrgid(gid_t gid)
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#else
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getgrgid(gid)
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gid_t gid;
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#endif
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{
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int rval;
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if (!start_gr())
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return(NULL);
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rval = grscan(1, gid, NULL);
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#ifdef YP
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if(!rval && _gr_yp_enabled) {
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char buf[16];
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snprintf(buf, sizeof buf, "%d", (unsigned)gid);
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rval = _getypgroup(&_gr_group, buf, "group.bygid");
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}
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#endif
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if (!_gr_stayopen)
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endgrent();
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return(rval ? &_gr_group : NULL);
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}
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static int
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start_gr()
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{
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if (_gr_fp) {
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rewind(_gr_fp);
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return(1);
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}
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_gr_fp = fopen(_PATH_GROUP, "r");
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if(!_gr_fp) return 0;
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#ifdef YP
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/*
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* This is a disgusting hack, used to determine when YP is enabled.
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* This would be easier if we had a group database to go along with
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* the password database.
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*/
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{
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char *line;
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size_t linelen;
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_gr_yp_enabled = 0;
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while(line = fgetln(_gr_fp, &linelen)) {
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if(line[0] == '+') {
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if(line[1] && !_gr_yp_enabled) {
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_gr_yp_enabled = 1;
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} else {
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_gr_yp_enabled = -1;
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break;
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}
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}
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}
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rewind(_gr_fp);
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}
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#endif
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return 1;
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}
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int
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setgrent()
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{
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return(setgroupent(0));
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}
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int
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setgroupent(stayopen)
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int stayopen;
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{
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if (!start_gr())
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return(0);
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_gr_stayopen = stayopen;
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#ifdef YP
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_gr_stepping_yp = 0;
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#endif
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return(1);
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}
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void
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endgrent()
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{
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#ifdef YP
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_gr_stepping_yp = 0;
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#endif
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if (_gr_fp) {
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(void)fclose(_gr_fp);
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_gr_fp = NULL;
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}
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}
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static int
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grscan(search, gid, name)
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register int search, gid;
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register char *name;
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{
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register char *cp, **m;
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char *bp;
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char *fgets(), *strsep(), *index();
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for (;;) {
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if (!fgets(line, sizeof(line), _gr_fp))
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return(0);
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bp = line;
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/* skip lines that are too big */
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if (!index(line, '\n')) {
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int ch;
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while ((ch = getc(_gr_fp)) != '\n' && ch != EOF)
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;
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continue;
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}
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_gr_group.gr_name = strsep(&bp, ":\n");
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if (search && name) {
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#ifdef YP
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if(_gr_group.gr_name[0] == '+') {
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if(strcmp(&_gr_group.gr_name[1], name)) {
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continue;
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}
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return _getypgroup(&_gr_group, name,
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"group.byname");
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}
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#endif /* YP */
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if(strcmp(_gr_group.gr_name, name)) {
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continue;
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}
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}
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#ifdef YP
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/*
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* XXX We need to be careful to avoid proceeding
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* past this point under certain circumstances or
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* we risk dereferencing null pointers down below.
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*/
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if (_gr_group.gr_name[0] == '+') {
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switch(search) {
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case 0:
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return(1);
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case 1:
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return(0);
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default:
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return(0);
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}
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}
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#endif /* YP */
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_gr_group.gr_passwd = strsep(&bp, ":\n");
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if (!(cp = strsep(&bp, ":\n")))
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continue;
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_gr_group.gr_gid = atoi(cp);
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if (search && name == NULL && _gr_group.gr_gid != gid)
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continue;
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cp = NULL;
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for (m = _gr_group.gr_mem = members;; bp++) {
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if (m == &members[MAXGRP - 1])
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break;
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if (*bp == ',') {
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if (cp) {
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*bp = '\0';
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*m++ = cp;
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cp = NULL;
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}
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} else if (*bp == '\0' || *bp == '\n' || *bp == ' ') {
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if (cp) {
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*bp = '\0';
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*m++ = cp;
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}
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break;
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} else if (cp == NULL)
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cp = bp;
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}
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*m = NULL;
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return(1);
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}
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/* NOTREACHED */
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}
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#ifdef YP
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static int
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_gr_breakout_yp(struct group *gr, char *result)
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{
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char *s, *cp;
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char **m;
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/*
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* XXX If 's' ends up being a NULL pointer, punt on this group.
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* It means the NIS group entry is badly formatted and should
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* be skipped.
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*/
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if ((s = strsep(&result, ":")) == NULL) return 0; /* name */
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gr->gr_name = s;
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if ((s = strsep(&result, ":")) == NULL) return 0; /* password */
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gr->gr_passwd = s;
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if ((s = strsep(&result, ":")) == NULL) return 0; /* gid */
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gr->gr_gid = atoi(s);
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if ((s = result) == NULL) return 0;
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cp = 0;
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for (m = _gr_group.gr_mem = members; /**/; s++) {
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if (m == &members[MAXGRP - 1]) {
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break;
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}
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if (*s == ',') {
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if (cp) {
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*s = '\0';
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*m++ = cp;
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cp = NULL;
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}
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} else if (*s == '\0' || *s == '\n' || *s == ' ') {
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if (cp) {
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*s = '\0';
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*m++ = cp;
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}
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break;
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} else if (cp == NULL) {
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cp = s;
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}
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}
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*m = NULL;
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return 1;
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}
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static char *_gr_yp_domain;
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static int
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_getypgroup(struct group *gr, const char *name, char *map)
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{
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char *result, *s;
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static char resultbuf[1024];
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int resultlen;
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if(!_gr_yp_domain) {
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if(yp_get_default_domain(&_gr_yp_domain))
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return 0;
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}
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if(yp_match(_gr_yp_domain, map, name, strlen(name),
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&result, &resultlen))
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return 0;
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s = strchr(result, '\n');
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if(s) *s = '\0';
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if(resultlen >= sizeof resultbuf) return 0;
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strcpy(resultbuf, result);
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result = resultbuf;
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return(_gr_breakout_yp(gr, resultbuf));
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}
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static int
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_nextypgroup(struct group *gr)
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{
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static char *key;
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static int keylen;
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char *lastkey, *result;
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static char resultbuf[1024];
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int resultlen;
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int rv;
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if(!_gr_yp_domain) {
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if(yp_get_default_domain(&_gr_yp_domain))
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return 0;
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}
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if(!_gr_stepping_yp) {
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if(key) free(key);
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rv = yp_first(_gr_yp_domain, "group.byname",
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&key, &keylen, &result, &resultlen);
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if(rv) {
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return 0;
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}
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_gr_stepping_yp = 1;
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goto unpack;
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} else {
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tryagain:
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lastkey = key;
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rv = yp_next(_gr_yp_domain, "group.byname", key, keylen,
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&key, &keylen, &result, &resultlen);
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free(lastkey);
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unpack:
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if(rv) {
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_gr_stepping_yp = 0;
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return 0;
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}
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if(resultlen > sizeof(resultbuf)) {
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free(result);
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goto tryagain;
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}
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strcpy(resultbuf, result);
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free(result);
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if(result = strchr(resultbuf, '\n')) *result = '\0';
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return(_gr_breakout_yp(gr, resultbuf));
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}
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}
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#endif /* YP */
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