mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-23 11:18:54 +00:00
5ee7cd2107
Approved by: re (kensmith)
382 lines
7.9 KiB
C
382 lines
7.9 KiB
C
/* $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/cdefs.h>
|
|
__FBSDID("$FreeBSD$");
|
|
|
|
#include <sys/types.h>
|
|
#include <sys/time.h>
|
|
#include <sys/socket.h>
|
|
|
|
#include <net/if.h>
|
|
#include <net/bpf.h>
|
|
|
|
#include <err.h>
|
|
#include <errno.h>
|
|
#include <fcntl.h>
|
|
#include <limits.h>
|
|
#ifndef __FreeBSD__
|
|
#include <pcap.h>
|
|
#include <pcap-int.h>
|
|
#endif
|
|
#include <pwd.h>
|
|
#include <signal.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#ifdef __FreeBSD__
|
|
/* XXX: pcap pollutes namespace with strlcpy if not present previously */
|
|
#include <pcap.h>
|
|
#include <pcap-int.h>
|
|
#endif
|
|
#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;
|
|
|
|
#ifdef __FreeBSD__
|
|
for (i = 1; i < NSIG; i++)
|
|
#else
|
|
for (i = 1; i < _NSIG; i++)
|
|
#endif
|
|
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;
|
|
}
|
|
}
|
|
}
|