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-rw-r--r--pflogd/privsep.c367
1 files changed, 367 insertions, 0 deletions
diff --git a/pflogd/privsep.c b/pflogd/privsep.c
new file mode 100644
index 000000000000..1139cb40f96b
--- /dev/null
+++ b/pflogd/privsep.c
@@ -0,0 +1,367 @@
+/* $OpenBSD: privsep.c,v 1.16 2006/10/25 20:55:04 moritz Exp $ */
+
+/*
+ * Copyright (c) 2003 Can Erkin Acar
+ * Copyright (c) 2003 Anil Madhavapeddy <anil@recoil.org>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/socket.h>
+#include <sys/ioctl.h>
+
+#include <net/if.h>
+#include <net/bpf.h>
+
+#include <err.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <pcap.h>
+#include <pcap-int.h>
+#include <pwd.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <syslog.h>
+#include <unistd.h>
+#include "pflogd.h"
+
+enum cmd_types {
+ PRIV_SET_SNAPLEN, /* set the snaplength */
+ PRIV_MOVE_LOG, /* move logfile away */
+ PRIV_OPEN_LOG /* open logfile for appending */
+};
+
+static int priv_fd = -1;
+static volatile pid_t child_pid = -1;
+
+volatile sig_atomic_t gotsig_chld = 0;
+
+static void sig_pass_to_chld(int);
+static void sig_chld(int);
+static int may_read(int, void *, size_t);
+static void must_read(int, void *, size_t);
+static void must_write(int, void *, size_t);
+static int set_snaplen(int snap);
+static int move_log(const char *name);
+
+extern char *filename;
+extern pcap_t *hpcap;
+
+/* based on syslogd privsep */
+int
+priv_init(void)
+{
+ int i, fd, socks[2], cmd;
+ int snaplen, ret, olderrno;
+ struct passwd *pw;
+
+ for (i = 1; i < _NSIG; i++)
+ signal(i, SIG_DFL);
+
+ /* Create sockets */
+ if (socketpair(AF_LOCAL, SOCK_STREAM, PF_UNSPEC, socks) == -1)
+ err(1, "socketpair() failed");
+
+ pw = getpwnam("_pflogd");
+ if (pw == NULL)
+ errx(1, "unknown user _pflogd");
+ endpwent();
+
+ child_pid = fork();
+ if (child_pid < 0)
+ err(1, "fork() failed");
+
+ if (!child_pid) {
+ gid_t gidset[1];
+
+ /* Child - drop privileges and return */
+ if (chroot(pw->pw_dir) != 0)
+ err(1, "unable to chroot");
+ if (chdir("/") != 0)
+ err(1, "unable to chdir");
+
+ gidset[0] = pw->pw_gid;
+ if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) == -1)
+ err(1, "setresgid() failed");
+ if (setgroups(1, gidset) == -1)
+ err(1, "setgroups() failed");
+ if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) == -1)
+ err(1, "setresuid() failed");
+ close(socks[0]);
+ priv_fd = socks[1];
+ return 0;
+ }
+
+ /* Father */
+ /* Pass ALRM/TERM/HUP/INT/QUIT through to child, and accept CHLD */
+ signal(SIGALRM, sig_pass_to_chld);
+ signal(SIGTERM, sig_pass_to_chld);
+ signal(SIGHUP, sig_pass_to_chld);
+ signal(SIGINT, sig_pass_to_chld);
+ signal(SIGQUIT, sig_pass_to_chld);
+ signal(SIGCHLD, sig_chld);
+
+ setproctitle("[priv]");
+ close(socks[1]);
+
+ while (!gotsig_chld) {
+ if (may_read(socks[0], &cmd, sizeof(int)))
+ break;
+ switch (cmd) {
+ case PRIV_SET_SNAPLEN:
+ logmsg(LOG_DEBUG,
+ "[priv]: msg PRIV_SET_SNAPLENGTH received");
+ must_read(socks[0], &snaplen, sizeof(int));
+
+ ret = set_snaplen(snaplen);
+ if (ret) {
+ logmsg(LOG_NOTICE,
+ "[priv]: set_snaplen failed for snaplen %d",
+ snaplen);
+ }
+
+ must_write(socks[0], &ret, sizeof(int));
+ break;
+
+ case PRIV_OPEN_LOG:
+ logmsg(LOG_DEBUG,
+ "[priv]: msg PRIV_OPEN_LOG received");
+ /* create or append logs but do not follow symlinks */
+ fd = open(filename,
+ O_RDWR|O_CREAT|O_APPEND|O_NONBLOCK|O_NOFOLLOW,
+ 0600);
+ olderrno = errno;
+ send_fd(socks[0], fd);
+ if (fd < 0)
+ logmsg(LOG_NOTICE,
+ "[priv]: failed to open %s: %s",
+ filename, strerror(olderrno));
+ else
+ close(fd);
+ break;
+
+ case PRIV_MOVE_LOG:
+ logmsg(LOG_DEBUG,
+ "[priv]: msg PRIV_MOVE_LOG received");
+ ret = move_log(filename);
+ must_write(socks[0], &ret, sizeof(int));
+ break;
+
+ default:
+ logmsg(LOG_ERR, "[priv]: unknown command %d", cmd);
+ _exit(1);
+ /* NOTREACHED */
+ }
+ }
+
+ _exit(1);
+}
+
+/* this is called from parent */
+static int
+set_snaplen(int snap)
+{
+ if (hpcap == NULL)
+ return (1);
+
+ hpcap->snapshot = snap;
+ set_pcap_filter();
+
+ return 0;
+}
+
+static int
+move_log(const char *name)
+{
+ char ren[PATH_MAX];
+ int len;
+
+ for (;;) {
+ int fd;
+
+ len = snprintf(ren, sizeof(ren), "%s.bad.%08x",
+ name, arc4random());
+ if (len >= sizeof(ren)) {
+ logmsg(LOG_ERR, "[priv] new name too long");
+ return (1);
+ }
+
+ /* lock destinanion */
+ fd = open(ren, O_CREAT|O_EXCL, 0);
+ if (fd >= 0) {
+ close(fd);
+ break;
+ }
+ /* if file exists, try another name */
+ if (errno != EEXIST && errno != EINTR) {
+ logmsg(LOG_ERR, "[priv] failed to create new name: %s",
+ strerror(errno));
+ return (1);
+ }
+ }
+
+ if (rename(name, ren)) {
+ logmsg(LOG_ERR, "[priv] failed to rename %s to %s: %s",
+ name, ren, strerror(errno));
+ return (1);
+ }
+
+ logmsg(LOG_NOTICE,
+ "[priv]: log file %s moved to %s", name, ren);
+
+ return (0);
+}
+
+/*
+ * send the snaplength to privileged process
+ */
+int
+priv_set_snaplen(int snaplen)
+{
+ int cmd, ret;
+
+ if (priv_fd < 0)
+ errx(1, "%s: called from privileged portion", __func__);
+
+ cmd = PRIV_SET_SNAPLEN;
+
+ must_write(priv_fd, &cmd, sizeof(int));
+ must_write(priv_fd, &snaplen, sizeof(int));
+
+ must_read(priv_fd, &ret, sizeof(int));
+
+ /* also set hpcap->snapshot in child */
+ if (ret == 0)
+ hpcap->snapshot = snaplen;
+
+ return (ret);
+}
+
+/* Open log-file */
+int
+priv_open_log(void)
+{
+ int cmd, fd;
+
+ if (priv_fd < 0)
+ errx(1, "%s: called from privileged portion", __func__);
+
+ cmd = PRIV_OPEN_LOG;
+ must_write(priv_fd, &cmd, sizeof(int));
+ fd = receive_fd(priv_fd);
+
+ return (fd);
+}
+/* Move-away and reopen log-file */
+int
+priv_move_log(void)
+{
+ int cmd, ret;
+
+ if (priv_fd < 0)
+ errx(1, "%s: called from privileged portion\n", __func__);
+
+ cmd = PRIV_MOVE_LOG;
+ must_write(priv_fd, &cmd, sizeof(int));
+ must_read(priv_fd, &ret, sizeof(int));
+
+ return (ret);
+}
+
+/* If priv parent gets a TERM or HUP, pass it through to child instead */
+static void
+sig_pass_to_chld(int sig)
+{
+ int oerrno = errno;
+
+ if (child_pid != -1)
+ kill(child_pid, sig);
+ errno = oerrno;
+}
+
+/* if parent gets a SIGCHLD, it will exit */
+static void
+sig_chld(int sig)
+{
+ gotsig_chld = 1;
+}
+
+/* Read all data or return 1 for error. */
+static int
+may_read(int fd, void *buf, size_t n)
+{
+ char *s = buf;
+ ssize_t res, pos = 0;
+
+ while (n > pos) {
+ res = read(fd, s + pos, n - pos);
+ switch (res) {
+ case -1:
+ if (errno == EINTR || errno == EAGAIN)
+ continue;
+ case 0:
+ return (1);
+ default:
+ pos += res;
+ }
+ }
+ return (0);
+}
+
+/* Read data with the assertion that it all must come through, or
+ * else abort the process. Based on atomicio() from openssh. */
+static void
+must_read(int fd, void *buf, size_t n)
+{
+ char *s = buf;
+ ssize_t res, pos = 0;
+
+ while (n > pos) {
+ res = read(fd, s + pos, n - pos);
+ switch (res) {
+ case -1:
+ if (errno == EINTR || errno == EAGAIN)
+ continue;
+ case 0:
+ _exit(0);
+ default:
+ pos += res;
+ }
+ }
+}
+
+/* Write data with the assertion that it all has to be written, or
+ * else abort the process. Based on atomicio() from openssh. */
+static void
+must_write(int fd, void *buf, size_t n)
+{
+ char *s = buf;
+ ssize_t res, pos = 0;
+
+ while (n > pos) {
+ res = write(fd, s + pos, n - pos);
+ switch (res) {
+ case -1:
+ if (errno == EINTR || errno == EAGAIN)
+ continue;
+ case 0:
+ _exit(0);
+ default:
+ pos += res;
+ }
+ }
+}
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