1 /* $OpenBSD: privsep.c,v 1.16 2006/10/25 20:55:04 moritz Exp $ */
4 * Copyright (c) 2003 Can Erkin Acar
5 * Copyright (c) 2003 Anil Madhavapeddy <anil@recoil.org>
7 * Permission to use, copy, modify, and distribute this software for any
8 * purpose with or without fee is hereby granted, provided that the above
9 * copyright notice and this permission notice appear in all copies.
11 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
17 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
20 #include <sys/types.h>
22 #include <sys/socket.h>
23 #include <sys/ioctl.h>
44 PRIV_SET_SNAPLEN, /* set the snaplength */
45 PRIV_MOVE_LOG, /* move logfile away */
46 PRIV_OPEN_LOG /* open logfile for appending */
49 static int priv_fd = -1;
50 static volatile pid_t child_pid = -1;
52 volatile sig_atomic_t gotsig_chld = 0;
54 static void sig_pass_to_chld(int);
55 static void sig_chld(int);
56 static int may_read(int, void *, size_t);
57 static void must_read(int, void *, size_t);
58 static void must_write(int, void *, size_t);
59 static int set_snaplen(int snap);
60 static int move_log(const char *name);
62 extern char *filename;
65 /* based on syslogd privsep */
69 int i, fd, socks[2], cmd;
70 int snaplen, ret, olderrno;
74 for (i = 1; i < NSIG; i++)
76 for (i = 1; i < _NSIG; i++)
81 if (socketpair(AF_LOCAL, SOCK_STREAM, PF_UNSPEC, socks) == -1)
82 err(1, "socketpair() failed");
84 pw = getpwnam("_pflogd");
86 errx(1, "unknown user _pflogd");
91 err(1, "fork() failed");
96 /* Child - drop privileges and return */
97 if (chroot(pw->pw_dir) != 0)
98 err(1, "unable to chroot");
100 err(1, "unable to chdir");
102 gidset[0] = pw->pw_gid;
103 if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) == -1)
104 err(1, "setresgid() failed");
105 if (setgroups(1, gidset) == -1)
106 err(1, "setgroups() failed");
107 if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) == -1)
108 err(1, "setresuid() failed");
115 /* Pass ALRM/TERM/HUP/INT/QUIT through to child, and accept CHLD */
116 signal(SIGALRM, sig_pass_to_chld);
117 signal(SIGTERM, sig_pass_to_chld);
118 signal(SIGHUP, sig_pass_to_chld);
119 signal(SIGINT, sig_pass_to_chld);
120 signal(SIGQUIT, sig_pass_to_chld);
121 signal(SIGCHLD, sig_chld);
123 setproctitle("[priv]");
126 while (!gotsig_chld) {
127 if (may_read(socks[0], &cmd, sizeof(int)))
130 case PRIV_SET_SNAPLEN:
132 "[priv]: msg PRIV_SET_SNAPLENGTH received");
133 must_read(socks[0], &snaplen, sizeof(int));
135 ret = set_snaplen(snaplen);
138 "[priv]: set_snaplen failed for snaplen %d",
142 must_write(socks[0], &ret, sizeof(int));
147 "[priv]: msg PRIV_OPEN_LOG received");
148 /* create or append logs but do not follow symlinks */
150 O_RDWR|O_CREAT|O_APPEND|O_NONBLOCK|O_NOFOLLOW,
153 send_fd(socks[0], fd);
156 "[priv]: failed to open %s: %s",
157 filename, strerror(olderrno));
164 "[priv]: msg PRIV_MOVE_LOG received");
165 ret = move_log(filename);
166 must_write(socks[0], &ret, sizeof(int));
170 logmsg(LOG_ERR, "[priv]: unknown command %d", cmd);
179 /* this is called from parent */
181 set_snaplen(int snap)
186 hpcap->snapshot = snap;
193 move_log(const char *name)
201 len = snprintf(ren, sizeof(ren), "%s.bad.%08x",
203 if (len >= sizeof(ren)) {
204 logmsg(LOG_ERR, "[priv] new name too long");
208 /* lock destinanion */
209 fd = open(ren, O_CREAT|O_EXCL, 0);
214 /* if file exists, try another name */
215 if (errno != EEXIST && errno != EINTR) {
216 logmsg(LOG_ERR, "[priv] failed to create new name: %s",
222 if (rename(name, ren)) {
223 logmsg(LOG_ERR, "[priv] failed to rename %s to %s: %s",
224 name, ren, strerror(errno));
229 "[priv]: log file %s moved to %s", name, ren);
235 * send the snaplength to privileged process
238 priv_set_snaplen(int snaplen)
243 errx(1, "%s: called from privileged portion", __func__);
245 cmd = PRIV_SET_SNAPLEN;
247 must_write(priv_fd, &cmd, sizeof(int));
248 must_write(priv_fd, &snaplen, sizeof(int));
250 must_read(priv_fd, &ret, sizeof(int));
252 /* also set hpcap->snapshot in child */
254 hpcap->snapshot = snaplen;
266 errx(1, "%s: called from privileged portion", __func__);
269 must_write(priv_fd, &cmd, sizeof(int));
270 fd = receive_fd(priv_fd);
274 /* Move-away and reopen log-file */
281 errx(1, "%s: called from privileged portion\n", __func__);
284 must_write(priv_fd, &cmd, sizeof(int));
285 must_read(priv_fd, &ret, sizeof(int));
290 /* If priv parent gets a TERM or HUP, pass it through to child instead */
292 sig_pass_to_chld(int sig)
297 kill(child_pid, sig);
301 /* if parent gets a SIGCHLD, it will exit */
308 /* Read all data or return 1 for error. */
310 may_read(int fd, void *buf, size_t n)
313 ssize_t res, pos = 0;
316 res = read(fd, s + pos, n - pos);
319 if (errno == EINTR || errno == EAGAIN)
330 /* Read data with the assertion that it all must come through, or
331 * else abort the process. Based on atomicio() from openssh. */
333 must_read(int fd, void *buf, size_t n)
336 ssize_t res, pos = 0;
339 res = read(fd, s + pos, n - pos);
342 if (errno == EINTR || errno == EAGAIN)
352 /* Write data with the assertion that it all has to be written, or
353 * else abort the process. Based on atomicio() from openssh. */
355 must_write(int fd, void *buf, size_t n)
358 ssize_t res, pos = 0;
361 res = write(fd, s + pos, n - pos);
364 if (errno == EINTR || errno == EAGAIN)