1 /*	$OpenBSD: check_script.c,v 1.23 2026/03/02 19:28:01 rsadowski Exp $	*/
2 
3 /*
4  * Copyright (c) 2007 - 2014 Reyk Floeter <reyk@openbsd.org>
5  *
6  * Permission to use, copy, modify, and distribute this software for any
7  * purpose with or without fee is hereby granted, provided that the above
8  * copyright notice and this permission notice appear in all copies.
9  *
10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17  */
18 
19 #include <sys/wait.h>
20 #include <sys/time.h>
21 
22 #include <errno.h>
23 #include <unistd.h>
24 #include <string.h>
25 #include <stdlib.h>
26 #include <signal.h>
27 #include <pwd.h>
28 
29 #include "relayd.h"
30 #include "log.h"
31 
32 void	 script_sig_alarm(int);
33 
34 pid_t			 child = -1;
35 
36 void
37 check_script(struct relayd *env, struct host *host)
38 {
39 	struct ctl_script	 scr;
40 	struct table		*table;
41 
42 	if ((host->flags & (F_CHECK_SENT|F_CHECK_DONE)) == F_CHECK_SENT)
43 		return;
44 
45 	if ((table = table_find(env, host->conf.tableid)) == NULL)
46 		fatalx("%s: invalid table id", __func__);
47 
48 	host->last_up = host->up;
49 	host->flags &= ~(F_CHECK_SENT|F_CHECK_DONE);
50 
51 	scr.host = host->conf.id;
52 	if ((strlcpy(scr.name, host->conf.name,sizeof(scr.name)) >=
53 	    sizeof(scr.name)) ||
54 	    (strlcpy(scr.path, table->conf.path, sizeof(scr.path)) >=
55 	    sizeof(scr.path)))
56 		fatalx("invalid script path");
57 	memcpy(&scr.timeout, &table->conf.timeout, sizeof(scr.timeout));
58 
59 	if (proc_compose(env->sc_ps, PROC_PARENT, IMSG_SCRIPT, &scr,
60 	    sizeof(scr)) == 0)
61 		host->flags |= F_CHECK_SENT;
62 }
63 
64 void
65 script_done(struct relayd *env, struct ctl_script *scr)
66 {
67 	struct host		*host;
68 
69 	if ((host = host_find(env, scr->host)) == NULL)
70 		fatalx("%s: invalid host id", __func__);
71 
72 	if (scr->retval < 0)
73 		host->up = HOST_UNKNOWN;
74 	else if (scr->retval == 0)
75 		host->up = HOST_DOWN;
76 	else
77 		host->up = HOST_UP;
78 	host->flags |= F_CHECK_DONE;
79 
80 	hce_notify_done(host, host->up == HOST_UP ?
81 	    HCE_SCRIPT_OK : HCE_SCRIPT_FAIL);
82 }
83 
84 void
85 script_sig_alarm(int sig)
86 {
87 	int save_errno = errno;
88 
89 	if (child != -1)
90 		kill(child, SIGKILL);
91 	errno = save_errno;
92 }
93 
94 int
95 script_exec(struct relayd *env, struct ctl_script *scr)
96 {
97 	int			 status = 0, ret = 0;
98 	sig_t			 save_quit, save_int, save_chld;
99 	struct itimerval	 it;
100 	struct timeval		*tv;
101 	const char		*file, *arg;
102 	struct passwd		*pw;
103 
104 	if ((env->sc_conf.flags & F_SCRIPT) == 0) {
105 		log_warnx("%s: script disabled", __func__);
106 		return (-1);
107 	}
108 
109 	DPRINTF("%s: running script %s, host %s",
110 	    __func__, scr->path, scr->name);
111 
112 	arg = scr->name;
113 	file = scr->path;
114 	tv = &scr->timeout;
115 
116 	save_quit = signal(SIGQUIT, SIG_IGN);
117 	save_int = signal(SIGINT, SIG_IGN);
118 	save_chld = signal(SIGCHLD, SIG_DFL);
119 
120 	switch (child = fork()) {
121 	case -1:
122 		ret = -1;
123 		goto done;
124 	case 0:
125 		signal(SIGQUIT, SIG_DFL);
126 		signal(SIGINT, SIG_DFL);
127 		signal(SIGCHLD, SIG_DFL);
128 
129 		if ((pw = getpwnam(RELAYD_USER)) == NULL)
130 			fatal("%s: getpwnam", __func__);
131 		if (chdir("/") == -1)
132 			fatal("%s: chdir(\"/\")", __func__);
133 		if (setgroups(1, &pw->pw_gid) ||
134 		    setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) ||
135 		    setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid))
136 			fatal("%s: can't drop privileges", __func__);
137 
138 		/*
139 		 * close fds before executing an external program, to
140 		 * prevent access to internal fds, eg. IMSG connections
141 		 * of internal processes.
142 		 */
143 		closefrom(STDERR_FILENO + 1);
144 
145 		execlp(file, file, arg, (char *)NULL);
146 		_exit(0);
147 		break;
148 	default:
149 		/* Kill the process after a timeout */
150 		signal(SIGALRM, script_sig_alarm);
151 		bzero(&it, sizeof(it));
152 		bcopy(tv, &it.it_value, sizeof(it.it_value));
153 		setitimer(ITIMER_REAL, &it, NULL);
154 
155 		waitpid(child, &status, 0);
156 		break;
157 	}
158 
159 	switch (ret) {
160 	case -1:
161 		ret = -1;
162 		break;
163 	default:
164 		if (WIFEXITED(status))
165 			ret = WEXITSTATUS(status);
166 		else
167 			ret = 0;
168 	}
169 
170  done:
171 	/* Disable the process timeout timer */
172 	bzero(&it, sizeof(it));
173 	setitimer(ITIMER_REAL, &it, NULL);
174 	child = -1;
175 
176 	signal(SIGQUIT, save_quit);
177 	signal(SIGINT, save_int);
178 	signal(SIGCHLD, save_chld);
179 	signal(SIGALRM, SIG_DFL);
180 
181 	return (ret);
182 }