Reorganize the relayd code to use the proc.c privsep API/commodity

functions that are based on work for iked and smtpd.  This simplifies
the setup of privsep processes and moves some redundant and repeated
code to a single place - which is always good from a quality and
security point of view.  The relayd version of proc.c is different to
the current version in iked because it uses 1:N communications between
processes, eg. a single parent process is talking to many forked relay
children while iked only needs 1:1 communications.

ok sthen@ pyr@

1 files changed, 568 insertions, 0 deletions

diff --git a/usr.sbin/relayd/proc.c b/usr.sbin/relayd/proc.c
new file mode 100644
index 00000000000..2bfb76a85be
--- /dev/null
+++ b/usr.sbin/relayd/proc.c
@@ -0,0 +1,568 @@
+/*	$OpenBSD: proc.c,v 1.1 2011/05/09 12:09:58 reyk Exp $	*/
+
+/*
+ * Copyright (c) 2010,2011 Reyk Floeter <reyk@openbsd.org>
+ * Copyright (c) 2008 Pierre-Yves Ritschard <pyr@openbsd.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/queue.h>
+#include <sys/socket.h>
+#include <sys/wait.h>
+#include <sys/tree.h>
+
+#include <net/if.h>
+#include <netinet/in_systm.h>
+#include <netinet/in.h>
+#include <netinet/ip.h>
+#include <arpa/inet.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <signal.h>
+#include <pwd.h>
+#include <event.h>
+
+#include <openssl/rand.h>
+#include <openssl/ssl.h>
+
+#include "relayd.h"
+
+void	 proc_setup(struct privsep *);
+int	 proc_ispeer(struct privsep_proc *, u_int, enum privsep_procid);
+void	 proc_shutdown(struct privsep_proc *);
+void	 proc_sig_handler(int, short, void *);
+void	 proc_range(struct privsep *, enum privsep_procid, int *, int *);
+
+int
+proc_ispeer(struct privsep_proc *p, u_int nproc, enum privsep_procid type)
+{
+	u_int	i;
+
+	for (i = 0; i < nproc; i++)
+		if (p[i].p_id == type)
+			return (1);
+	return (0);
+}
+
+void
+proc_init(struct privsep *ps, struct privsep_proc *p, u_int nproc)
+{
+	u_int	 i;
+
+	/*
+	 * Called from parent
+	 */
+	privsep_process = PROC_PARENT;
+	ps->ps_instances[PROC_PARENT] = 1;
+	ps->ps_title[PROC_PARENT] = "parent";
+	ps->ps_pid[PROC_PARENT] = getpid();
+
+	for (i = 0; i < nproc; i++) {
+		/* Default to 1 process instance */
+		if (ps->ps_instances[p[i].p_id] < 1)
+			ps->ps_instances[p[i].p_id] = 1;
+		ps->ps_title[p[i].p_id] = p[i].p_title;
+	}
+
+	proc_setup(ps);
+
+	/* Engage! */
+	for (i = 0; i < nproc; i++)
+		ps->ps_pid[p[i].p_id] = (*p[i].p_init)(ps, &p[i]);
+}
+
+void
+proc_kill(struct privsep *ps)
+{
+	pid_t		 pid;
+	u_int		 i;
+
+	if (privsep_process != PROC_PARENT)
+		return;
+
+	for (i = 0; i < PROC_MAX; i++) {
+		if (ps->ps_pid[i] == 0)
+			continue;
+		killpg(ps->ps_pid[i], SIGTERM);
+	}
+
+	do {
+		pid = waitpid(WAIT_ANY, NULL, 0);
+	} while (pid != -1 || (pid == -1 && errno == EINTR));
+}
+
+void
+proc_setup(struct privsep *ps)
+{
+	int	 i, j, n, count, sockpair[2];
+
+	for (i = 0; i < PROC_MAX; i++)
+		for (j = 0; j < PROC_MAX; j++) {
+			/*
+			 * find out how many instances of this peer there are.
+			 */
+			if (i >= j || ps->ps_instances[i] == 0||
+			   ps->ps_instances[j] == 0)
+				continue;
+
+			if (ps->ps_instances[i] > 1 &&
+			    ps->ps_instances[j] > 1)
+				fatalx("N:M peering not supported");
+
+			count = ps->ps_instances[i] * ps->ps_instances[j];
+
+			if ((ps->ps_pipes[i][j] =
+			    calloc(count, sizeof(int))) == NULL ||
+			    (ps->ps_pipes[j][i] =
+			    calloc(count, sizeof(int))) == NULL)
+				fatal(NULL);
+
+			for (n = 0; n < count; n++) {
+				if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC,
+				    sockpair) == -1)
+					fatal("socketpair");
+				ps->ps_pipes[i][j][n] = sockpair[0];
+				ps->ps_pipes[j][i][n] = sockpair[1];
+				socket_set_blockmode(
+				    ps->ps_pipes[i][j][n],
+				    BM_NONBLOCK);
+				socket_set_blockmode(
+				    ps->ps_pipes[j][i][n],
+				    BM_NONBLOCK);
+			}
+		}
+}
+
+void
+proc_config(struct privsep *ps, struct privsep_proc *p, u_int nproc)
+{
+	u_int	i, j, src, dst, count, n, instance;
+
+	src = privsep_process;
+
+	/*
+	 * close unused pipes
+	 */
+	for (i = 0; i < PROC_MAX; i++) {
+		for (j = 0; j < PROC_MAX; j++) {
+			if (i == j ||
+			    ps->ps_instances[i] == 0 ||
+			    ps->ps_instances[j] == 0)
+				continue;
+
+			count = ps->ps_instances[i] * ps->ps_instances[j];
+
+			for (n = 0; n < count; n++) {
+				instance = ps->ps_instances[i] > 1 ? n : 0;
+				if (i == src &&
+				    proc_ispeer(p, nproc, j) &&
+				    ps->ps_instance == instance)
+					continue;
+
+				close(ps->ps_pipes[i][j][n]);
+				ps->ps_pipes[i][j][n] = -1;
+			}
+		}
+	}
+
+	/*
+	 * listen on appropriate pipes
+	 */
+	for (i = 0; i < nproc; i++) {
+		dst = p[i].p_id;
+		p[i].p_ps = ps;
+		p[i].p_env = ps->ps_env;
+
+		if (src == dst)
+			fatal("proc_config: cannot peer with oneself");
+
+		count = ps->ps_instances[src] * ps->ps_instances[dst];
+		
+		if ((ps->ps_ievs[dst] = calloc(count,
+		    sizeof(struct imsgev))) == NULL)
+			fatal("proc_config");
+
+		for (n = 0; n < count; n++) {
+			if (ps->ps_pipes[src][dst][n] == -1)
+				continue;
+
+			imsg_init(&(ps->ps_ievs[dst][n].ibuf),
+			    ps->ps_pipes[src][dst][n]);
+			ps->ps_ievs[dst][n].handler = proc_dispatch;
+			ps->ps_ievs[dst][n].events = EV_READ;
+			ps->ps_ievs[dst][n].proc = &p[i];
+			ps->ps_ievs[dst][n].data = &ps->ps_ievs[dst][n];
+			p[i].p_instance = n;
+
+			event_set(&(ps->ps_ievs[dst][n].ev),
+			    ps->ps_ievs[dst][n].ibuf.fd,
+			    ps->ps_ievs[dst][n].events,
+			    ps->ps_ievs[dst][n].handler,
+			    ps->ps_ievs[dst][n].data);
+			event_add(&(ps->ps_ievs[dst][n].ev), NULL);
+		}
+	}
+}
+
+void
+proc_shutdown(struct privsep_proc *p)
+{
+	struct privsep	*ps = p->p_ps;
+
+	if (p->p_id == PROC_CONTROL && ps)
+		control_cleanup(&ps->ps_csock);
+
+	if (p->p_shutdown != NULL)
+		(*p->p_shutdown)();
+
+	log_info("%s exiting, pid %d", p->p_title, getpid());
+
+	_exit(0);
+}
+
+void
+proc_sig_handler(int sig, short event, void *arg)
+{
+	struct privsep_proc	*p = arg;
+
+	switch (sig) {
+	case SIGINT:
+	case SIGTERM:
+		proc_shutdown(p);
+		break;
+	case SIGCHLD:
+	case SIGHUP:
+	case SIGPIPE:
+		/* ignore */
+		break;
+	default:
+		fatalx("proc_sig_handler: unexpected signal");
+		/* NOTREACHED */
+	}
+}
+
+pid_t
+proc_run(struct privsep *ps, struct privsep_proc *p,
+    struct privsep_proc *procs, u_int nproc,
+    void (*init)(struct privsep *, struct privsep_proc *, void *), void *arg)
+{
+	pid_t		 pid;
+	struct passwd	*pw;
+	const char	*root;
+	u_int32_t	 seed[256];
+	u_int		 n;
+
+	switch (pid = fork()) {
+	case -1:
+		fatal("run_proc: cannot fork");
+	case 0:
+		/* Set the process group of the current process */
+		setpgrp(0, getpid());
+		break;
+	default:
+		return (pid);
+	}
+
+	pw = ps->ps_pw;
+
+	if (p->p_id == PROC_CONTROL) {
+		if (control_init(ps, &ps->ps_csock) == -1)
+			fatalx(p->p_title);
+	}
+
+	/* Change root directory */
+	if (p->p_chroot != NULL)
+		root = p->p_chroot;
+	else
+		root = pw->pw_dir;
+
+#ifndef DEBUG
+	if (chroot(root) == -1)
+		fatal("run_proc: chroot");
+	if (chdir("/") == -1)
+		fatal("run_proc: chdir(\"/\")");
+#else
+#warning disabling privilege revocation and chroot in DEBUG MODE
+	if (p->p_chroot != NULL) {
+		if (chroot(root) == -1)
+			fatal("run_proc: chroot");
+		if (chdir("/") == -1)
+			fatal("run_proc: chdir(\"/\")");
+	}
+#endif
+
+	privsep_process = p->p_id;
+
+	setproctitle("%s", p->p_title);
+
+#ifndef DEBUG
+	if (setgroups(1, &pw->pw_gid) ||
+	    setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) ||
+	    setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid))
+		fatal("run_proc: cannot drop privileges");
+#endif
+
+	/* Fork child handlers */
+	for (n = 1; n < ps->ps_instances[p->p_id]; n++) {
+		if (fork() == 0) {
+			ps->ps_instance = p->p_instance = n;
+			break;
+		}
+	}
+
+#ifdef DEBUG
+	log_debug("%s: %s %d/%d, pid %d", __func__, p->p_title,
+	    ps->ps_instance + 1, ps->ps_instances[p->p_id], getpid());
+#endif
+
+	event_init();
+
+	signal_set(&ps->ps_evsigint, SIGINT, proc_sig_handler, p);
+	signal_set(&ps->ps_evsigterm, SIGTERM, proc_sig_handler, p);
+	signal_set(&ps->ps_evsigchld, SIGCHLD, proc_sig_handler, p);
+	signal_set(&ps->ps_evsighup, SIGHUP, proc_sig_handler, p);
+	signal_set(&ps->ps_evsigpipe, SIGPIPE, proc_sig_handler, p);
+
+	signal_add(&ps->ps_evsigint, NULL);
+	signal_add(&ps->ps_evsigterm, NULL);
+	signal_add(&ps->ps_evsigchld, NULL);
+	signal_add(&ps->ps_evsighup, NULL);
+	signal_add(&ps->ps_evsigpipe, NULL);
+
+	proc_config(ps, procs, nproc);
+
+	arc4random_buf(seed, sizeof(seed));
+	RAND_seed(seed, sizeof(seed));
+
+	if (p->p_id == PROC_CONTROL && ps->ps_instance == 0) {
+		TAILQ_INIT(&ctl_conns);
+		if (control_listen(&ps->ps_csock) == -1)
+			fatalx(p->p_title);
+	}
+
+	if (init != NULL)
+		init(ps, p, arg);
+
+	event_dispatch();
+
+	proc_shutdown(p);
+
+	return (0);
+}
+
+void
+proc_dispatch(int fd, short event, void *arg)
+{
+	struct imsgev		*iev = (struct imsgev *)arg;
+	struct privsep_proc	*p = iev->proc;
+	struct privsep		*ps = p->p_ps;
+	struct imsgbuf		*ibuf;
+	struct imsg		 imsg;
+	ssize_t			 n;
+	int			 verbose;
+	const char		*title;
+
+	title = ps->ps_title[privsep_process];
+	ibuf = &iev->ibuf;
+
+	if (event & EV_READ) {
+		if ((n = imsg_read(ibuf)) == -1)
+			fatal(title);
+		if (n == 0) {
+			/* this pipe is dead, so remove the event handler */
+			event_del(&iev->ev);
+			event_loopexit(NULL);
+			return;
+		}
+	}
+
+	if (event & EV_WRITE) {
+		if (msgbuf_write(&ibuf->w) == -1)
+			fatal(title);
+	}
+
+	for (;;) {
+		if ((n = imsg_get(ibuf, &imsg)) == -1)
+			fatal(title);
+		if (n == 0)
+			break;
+
+#ifdef DEBUG
+		log_debug("%s: %s %d got imsg %d from %s %d",
+		    __func__, title, ps->ps_instance + 1,
+		    imsg.hdr.type, p->p_title, p->p_instance);
+#endif
+
+		/*
+		 * Check the message with the program callback
+		 */
+		if ((p->p_cb)(fd, p, &imsg) == 0) {
+			/* Message was handled by the callback, continue */
+			imsg_free(&imsg);
+			continue;
+		}
+
+		/*
+		 * Generic message handling
+		 */
+		switch (imsg.hdr.type) {
+		case IMSG_CTL_VERBOSE:
+			IMSG_SIZE_CHECK(&imsg, &verbose);
+			memcpy(&verbose, imsg.data, sizeof(verbose));
+			log_verbose(verbose);
+			break;
+		default:
+			log_warnx("%s: %s %d got invalid imsg %d from %s %d",
+			    __func__, title, ps->ps_instance + 1,
+			    imsg.hdr.type, p->p_title, p->p_instance);
+			fatalx(title);
+		}
+		imsg_free(&imsg);
+	}
+	imsg_event_add(iev);
+}
+
+/*
+ * imsg helper functions
+ */
+
+void
+imsg_event_add(struct imsgev *iev)
+{
+	if (iev->handler == NULL) {
+		imsg_flush(&iev->ibuf);
+		return;
+	}
+
+	iev->events = EV_READ;
+	if (iev->ibuf.w.queued)
+		iev->events |= EV_WRITE;
+
+	event_del(&iev->ev);
+	event_set(&iev->ev, iev->ibuf.fd, iev->events, iev->handler, iev->data);
+	event_add(&iev->ev, NULL);
+}
+
+int
+imsg_compose_event(struct imsgev *iev, u_int16_t type, u_int32_t peerid,
+    pid_t pid, int fd, void *data, u_int16_t datalen)
+{
+	int	ret;
+
+	if ((ret = imsg_compose(&iev->ibuf, type, peerid,
+	    pid, fd, data, datalen)) == -1)
+		return (ret);
+	imsg_event_add(iev);
+	return (ret);
+}
+
+int
+imsg_composev_event(struct imsgev *iev, u_int16_t type, u_int32_t peerid,
+    pid_t pid, int fd, const struct iovec *iov, int iovcnt)
+{
+	int	ret;
+
+	if ((ret = imsg_composev(&iev->ibuf, type, peerid,
+	    pid, fd, iov, iovcnt)) == -1)
+		return (ret);
+	imsg_event_add(iev);
+	return (ret);
+}
+
+void
+proc_range(struct privsep *ps, enum privsep_procid id, int *n, int *m)
+{
+	if (*n == -1) {
+		/*
+		 * -1 means that the current process is
+		 * N:1 - one of many processes connected to a single peer,
+		 *       so find the right slot of the peer.
+		 * 1:N - a single process connected to many peers,
+		 *       so find the range of slots of all peers.
+		 */
+		if (ps->ps_instances[privsep_process] <=
+		    ps->ps_instances[id]) {
+			*n = 0;
+			*m = ps->ps_instances[id];
+			return;
+		}
+
+		*n = ps->ps_instance;
+		*m = ps->ps_instance + 1;
+	} else {
+		/* Use only a single slot of the specified peer process */
+		*m = *n + 1;
+	}
+}
+
+int
+proc_compose_imsg(struct privsep *ps, enum privsep_procid id, int n,
+    u_int16_t type, int fd, void *data, u_int16_t datalen)
+{
+	int	 m;
+
+	proc_range(ps, id, &n, &m);
+	for (; n < m; n++)
+		if (imsg_compose_event(&ps->ps_ievs[id][n],
+		    type, -1, 0, fd, data, datalen) == -1)
+			return (-1);
+	return (0);
+}
+
+int
+proc_composev_imsg(struct privsep *ps, enum privsep_procid id, int n,
+    u_int16_t type, int fd, const struct iovec *iov, int iovcnt)
+{
+	int	 m;
+
+	proc_range(ps, id, &n, &m);
+	for (; n < m; n++)
+		if (imsg_composev_event(&ps->ps_ievs[id][n],
+		    type, -1, 0, fd, iov, iovcnt) == -1)
+			return (-1);
+
+	return (0);
+}
+
+int
+proc_forward_imsg(struct privsep *ps, struct imsg *imsg,
+    enum privsep_procid id, int n)
+{
+	return (proc_compose_imsg(ps, id, n, imsg->hdr.type,
+	    imsg->fd, imsg->data, IMSG_DATA_SIZE(imsg)));
+}
+
+void
+proc_flush_imsg(struct privsep *ps, enum privsep_procid id, int n)
+{
+	int	 m;
+
+	proc_range(ps, id, &n, &m);
+	for (; n < m; n++)
+		imsg_flush(&ps->ps_ievs[id][n].ibuf);
+}
+
+struct imsgbuf *
+proc_ibuf(struct privsep *ps, enum privsep_procid id, int n)
+{
+	int	 m;
+
+	proc_range(ps, id, &n, &m);
+	return (&ps->ps_ievs[id][n].ibuf);
+}