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.
19 #include <sys/types.h>
21 #include <sys/socket.h>
22 #include <sys/ioctl.h>
43 PRIV_SET_SNAPLEN, /* set the snaplength */
44 PRIV_MOVE_LOG, /* move logfile away */
45 PRIV_OPEN_LOG /* open logfile for appending */
48 static int priv_fd = -1;
49 static volatile pid_t child_pid = -1;
51 volatile sig_atomic_t gotsig_chld = 0;
53 static void sig_pass_to_chld(int);
54 static void sig_chld(int);
55 static int may_read(int, void *, size_t);
56 static void must_read(int, void *, size_t);
57 static void must_write(int, void *, size_t);
58 static int set_snaplen(int snap);
59 static int move_log(const char *name);
61 extern char *filename;
64 /* based on syslogd privsep */
68 int i, fd, socks[2], cmd;
69 int snaplen, ret, olderrno;
72 for (i = 1; i < NSIG; i++)
76 if (socketpair(AF_LOCAL, SOCK_STREAM, PF_UNSPEC, socks) == -1)
77 err(1, "socketpair() failed");
79 pw = getpwnam("_pflogd");
81 errx(1, "unknown user _pflogd");
86 err(1, "fork() failed");
91 /* Child - drop privileges and return */
92 if (chroot(pw->pw_dir) != 0)
93 err(1, "unable to chroot");
95 err(1, "unable to chdir");
97 gidset[0] = pw->pw_gid;
98 if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) == -1)
99 err(1, "setresgid() failed");
100 if (setgroups(1, gidset) == -1)
101 err(1, "setgroups() failed");
102 if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) == -1)
103 err(1, "setresuid() failed");
110 /* Pass ALRM/TERM/HUP/INT/QUIT through to child, and accept CHLD */
111 signal(SIGALRM, sig_pass_to_chld);
112 signal(SIGTERM, sig_pass_to_chld);
113 signal(SIGHUP, sig_pass_to_chld);
114 signal(SIGINT, sig_pass_to_chld);
115 signal(SIGQUIT, sig_pass_to_chld);
116 signal(SIGCHLD, sig_chld);
118 setproctitle("[priv]");
121 while (!gotsig_chld) {
122 if (may_read(socks[0], &cmd, sizeof(int)))
125 case PRIV_SET_SNAPLEN:
127 "[priv]: msg PRIV_SET_SNAPLENGTH received");
128 must_read(socks[0], &snaplen, sizeof(int));
130 ret = set_snaplen(snaplen);
133 "[priv]: set_snaplen failed for snaplen %d",
137 must_write(socks[0], &ret, sizeof(int));
142 "[priv]: msg PRIV_OPEN_LOG received");
143 /* create or append logs but do not follow symlinks */
145 O_RDWR|O_CREAT|O_APPEND|O_NONBLOCK|O_NOFOLLOW,
148 send_fd(socks[0], fd);
151 "[priv]: failed to open %s: %s",
152 filename, strerror(olderrno));
159 "[priv]: msg PRIV_MOVE_LOG received");
160 ret = move_log(filename);
161 must_write(socks[0], &ret, sizeof(int));
165 logmsg(LOG_ERR, "[priv]: unknown command %d", cmd);
174 /* this is called from parent */
176 set_snaplen(int snap)
181 hpcap->snapshot = snap;
188 move_log(const char *name)
196 len = snprintf(ren, sizeof(ren), "%s.bad.%08x",
198 if (len >= sizeof(ren)) {
199 logmsg(LOG_ERR, "[priv] new name too long");
203 /* lock destinanion */
204 fd = open(ren, O_CREAT|O_EXCL, 0);
209 /* if file exists, try another name */
210 if (errno != EEXIST && errno != EINTR) {
211 logmsg(LOG_ERR, "[priv] failed to create new name: %s",
217 if (rename(name, ren)) {
218 logmsg(LOG_ERR, "[priv] failed to rename %s to %s: %s",
219 name, ren, strerror(errno));
224 "[priv]: log file %s moved to %s", name, ren);
230 * send the snaplength to privileged process
233 priv_set_snaplen(int snaplen)
238 errx(1, "%s: called from privileged portion", __func__);
240 cmd = PRIV_SET_SNAPLEN;
242 must_write(priv_fd, &cmd, sizeof(int));
243 must_write(priv_fd, &snaplen, sizeof(int));
245 must_read(priv_fd, &ret, sizeof(int));
247 /* also set hpcap->snapshot in child */
249 hpcap->snapshot = snaplen;
261 errx(1, "%s: called from privileged portion", __func__);
264 must_write(priv_fd, &cmd, sizeof(int));
265 fd = receive_fd(priv_fd);
269 /* Move-away and reopen log-file */
276 errx(1, "%s: called from privileged portion\n", __func__);
279 must_write(priv_fd, &cmd, sizeof(int));
280 must_read(priv_fd, &ret, sizeof(int));
285 /* If priv parent gets a TERM or HUP, pass it through to child instead */
287 sig_pass_to_chld(int sig)
292 kill(child_pid, sig);
296 /* if parent gets a SIGCHLD, it will exit */
298 sig_chld(int sig __unused)
303 /* Read all data or return 1 for error. */
305 may_read(int fd, void *buf, size_t n)
312 res = read(fd, s + pos, n - pos);
315 if (errno == EINTR || errno == EAGAIN)
326 /* Read data with the assertion that it all must come through, or
327 * else abort the process. Based on atomicio() from openssh. */
329 must_read(int fd, void *buf, size_t n)
336 res = read(fd, s + pos, n - pos);
339 if (errno == EINTR || errno == EAGAIN)
349 /* Write data with the assertion that it all has to be written, or
350 * else abort the process. Based on atomicio() from openssh. */
352 must_write(int fd, void *buf, size_t n)
359 res = write(fd, s + pos, n - pos);
362 if (errno == EINTR || errno == EAGAIN)