1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1983, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. Neither the name of the University nor the names of its contributors
16 * may be used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * SUCH DAMAGE.
30 */
31
32 /*
33 * process.c handles the requests, which can be of three types:
34 * ANNOUNCE - announce to a user that a talk is wanted
35 * LEAVE_INVITE - insert the request into the table
36 * LOOK_UP - look up to see if a request is waiting in
37 * in the table for the local user
38 * DELETE - delete invitation
39 */
40 #include <sys/param.h>
41 #include <sys/stat.h>
42 #include <sys/socket.h>
43 #include <netinet/in.h>
44 #include <protocols/talkd.h>
45 #include <ctype.h>
46 #include <err.h>
47 #include <netdb.h>
48 #include <paths.h>
49 #include <stdio.h>
50 #include <string.h>
51 #include <syslog.h>
52 #include <utmpx.h>
53
54 #include "extern.h"
55
56 void
process_request(CTL_MSG * mp,CTL_RESPONSE * rp)57 process_request(CTL_MSG *mp, CTL_RESPONSE *rp)
58 {
59 CTL_MSG *ptr;
60 char *s;
61
62 rp->vers = TALK_VERSION;
63 rp->type = mp->type;
64 rp->id_num = htonl(0);
65 if (mp->vers != TALK_VERSION) {
66 syslog(LOG_WARNING, "bad protocol version %d", mp->vers);
67 rp->answer = BADVERSION;
68 return;
69 }
70 mp->id_num = ntohl(mp->id_num);
71 mp->addr.sa_family = ntohs(mp->addr.sa_family);
72 if (mp->addr.sa_family != AF_INET) {
73 syslog(LOG_WARNING, "bad address, family %d",
74 mp->addr.sa_family);
75 rp->answer = BADADDR;
76 return;
77 }
78 mp->ctl_addr.sa_family = ntohs(mp->ctl_addr.sa_family);
79 if (mp->ctl_addr.sa_family != AF_INET) {
80 syslog(LOG_WARNING, "bad control address, family %d",
81 mp->ctl_addr.sa_family);
82 rp->answer = BADCTLADDR;
83 return;
84 }
85 for (s = mp->l_name; *s; s++)
86 if (!isprint(*s)) {
87 syslog(LOG_NOTICE, "illegal user name. Aborting");
88 rp->answer = FAILED;
89 return;
90 }
91 mp->pid = ntohl(mp->pid);
92 if (debug)
93 print_request("process_request", mp);
94 switch (mp->type) {
95
96 case ANNOUNCE:
97 do_announce(mp, rp);
98 break;
99
100 case LEAVE_INVITE:
101 ptr = find_request(mp);
102 if (ptr != (CTL_MSG *)0) {
103 rp->id_num = htonl(ptr->id_num);
104 rp->answer = SUCCESS;
105 } else
106 insert_table(mp, rp);
107 break;
108
109 case LOOK_UP:
110 ptr = find_match(mp);
111 if (ptr != (CTL_MSG *)0) {
112 rp->id_num = htonl(ptr->id_num);
113 rp->addr = ptr->addr;
114 rp->addr.sa_family = htons(ptr->addr.sa_family);
115 rp->answer = SUCCESS;
116 } else
117 rp->answer = NOT_HERE;
118 break;
119
120 case DELETE:
121 rp->answer = delete_invite(mp->id_num);
122 break;
123
124 default:
125 rp->answer = UNKNOWN_REQUEST;
126 break;
127 }
128 if (debug)
129 print_response("process_request", rp);
130 }
131
132 void
do_announce(CTL_MSG * mp,CTL_RESPONSE * rp)133 do_announce(CTL_MSG *mp, CTL_RESPONSE *rp)
134 {
135 struct hostent *hp;
136 CTL_MSG *ptr;
137 int result;
138
139 /* see if the user is logged */
140 result = find_user(mp->r_name, mp->r_tty);
141 if (result != SUCCESS) {
142 rp->answer = result;
143 return;
144 }
145 #define satosin(sa) ((struct sockaddr_in *)(void *)(sa))
146 hp = gethostbyaddr(&satosin(&mp->ctl_addr)->sin_addr,
147 sizeof (struct in_addr), AF_INET);
148 if (hp == (struct hostent *)0) {
149 rp->answer = MACHINE_UNKNOWN;
150 return;
151 }
152 ptr = find_request(mp);
153 if (ptr == (CTL_MSG *) 0) {
154 insert_table(mp, rp);
155 rp->answer = announce(mp, hp->h_name);
156 return;
157 }
158 if (mp->id_num > ptr->id_num) {
159 /*
160 * This is an explicit re-announce, so update the id_num
161 * field to avoid duplicates and re-announce the talk.
162 */
163 ptr->id_num = new_id();
164 rp->id_num = htonl(ptr->id_num);
165 rp->answer = announce(mp, hp->h_name);
166 } else {
167 /* a duplicated request, so ignore it */
168 rp->id_num = htonl(ptr->id_num);
169 rp->answer = SUCCESS;
170 }
171 }
172
173 /*
174 * Search utmp for the local user
175 */
176 int
find_user(const char * name,char * tty)177 find_user(const char *name, char *tty)
178 {
179 struct utmpx *ut;
180 int status;
181 struct stat statb;
182 time_t best = 0;
183 char ftty[sizeof(_PATH_DEV) - 1 + sizeof(ut->ut_line)];
184
185 setutxent();
186 status = NOT_HERE;
187 (void) strcpy(ftty, _PATH_DEV);
188 while ((ut = getutxent()) != NULL)
189 if (ut->ut_type == USER_PROCESS &&
190 strcmp(ut->ut_user, name) == 0) {
191 if (*tty == '\0' || best != 0) {
192 if (best == 0)
193 status = PERMISSION_DENIED;
194 /* no particular tty was requested */
195 (void) strcpy(ftty + sizeof(_PATH_DEV) - 1,
196 ut->ut_line);
197 if (stat(ftty, &statb) == 0) {
198 if (!(statb.st_mode & 020))
199 continue;
200 if (statb.st_atime > best) {
201 best = statb.st_atime;
202 (void) strcpy(tty, ut->ut_line);
203 status = SUCCESS;
204 continue;
205 }
206 }
207 }
208 if (strcmp(ut->ut_line, tty) == 0) {
209 status = SUCCESS;
210 break;
211 }
212 }
213 endutxent();
214 return (status);
215 }
216