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freebsd-dev/contrib/pf/authpf/authpf.c
Bjoern A. Zeeb e0bfbfce79 Update packet filter (pf) code to OpenBSD 4.5. 
You need to update userland (world and ports) tools
to be in sync with the kernel.

Submitted by:	mlaier
Submitted by:	eri
2011-06-28 11:57:25 +00:00

956 lines
23 KiB
C
Raw Blame History

/* $OpenBSD: authpf.c,v 1.112 2009/01/10 19:08:53 miod Exp $ */
/*
* Copyright (C) 1998 - 2007 Bob Beck (beck@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/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/types.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <net/if.h>
#include <net/pfvar.h>
#include <arpa/inet.h>
#include <err.h>
#include <errno.h>
#ifdef __FreeBSD__
#include <inttypes.h>
#endif
#include <login_cap.h>
#include <pwd.h>
#include <grp.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syslog.h>
#include <unistd.h>
#include "pathnames.h"
static int read_config(FILE *);
static void print_message(const char *);
static int allowed_luser(struct passwd *);
static int check_luser(const char *, char *);
static int remove_stale_rulesets(void);
static int recursive_ruleset_purge(char *, char *);
static int change_filter(int, const char *, const char *);
static int change_table(int, const char *);
static void authpf_kill_states(void);
int dev; /* pf device */
char anchorname[PF_ANCHOR_NAME_SIZE] = "authpf";
char rulesetname[MAXPATHLEN - PF_ANCHOR_NAME_SIZE - 2];
char tablename[PF_TABLE_NAME_SIZE] = "authpf_users";
int user_ip = 1; /* controls whether $user_ip is set */
FILE *pidfp;
int pidfd = -1;
char luser[MAXLOGNAME]; /* username */
char ipsrc[256]; /* ip as a string */
char pidfile[MAXPATHLEN]; /* we save pid in this file. */
struct timeval Tstart, Tend; /* start and end times of session */
volatile sig_atomic_t want_death;
static void need_death(int signo);
#ifdef __FreeBSD__
static __dead2 void do_death(int);
#else
static __dead void do_death(int);
#endif
extern char *__progname; /* program name */
/*
* User shell for authenticating gateways. Sole purpose is to allow
* a user to ssh to a gateway, and have the gateway modify packet
* filters to allow access, then remove access when the user finishes
* up. Meant to be used only from ssh(1) connections.
*/
int
main(void)
{
int lockcnt = 0, n;
FILE *config;
struct in6_addr ina;
struct passwd *pw;
char *cp;
gid_t gid;
uid_t uid;
const char *shell;
login_cap_t *lc;
if (strcmp(__progname, "-authpf-noip") == 0)
user_ip = 0;
config = fopen(PATH_CONFFILE, "r");
if (config == NULL) {
syslog(LOG_ERR, "cannot open %s (%m)", PATH_CONFFILE);
exit(1);
}
if ((cp = getenv("SSH_TTY")) == NULL) {
syslog(LOG_ERR, "non-interactive session connection for authpf");
exit(1);
}
if ((cp = getenv("SSH_CLIENT")) == NULL) {
syslog(LOG_ERR, "cannot determine connection source");
exit(1);
}
if (strlcpy(ipsrc, cp, sizeof(ipsrc)) >= sizeof(ipsrc)) {
syslog(LOG_ERR, "SSH_CLIENT variable too long");
exit(1);
}
cp = strchr(ipsrc, ' ');
if (!cp) {
syslog(LOG_ERR, "corrupt SSH_CLIENT variable %s", ipsrc);
exit(1);
}
*cp = '\0';
if (inet_pton(AF_INET, ipsrc, &ina) != 1 &&
inet_pton(AF_INET6, ipsrc, &ina) != 1) {
syslog(LOG_ERR,
"cannot determine IP from SSH_CLIENT %s", ipsrc);
exit(1);
}
/* open the pf device */
dev = open(PATH_DEVFILE, O_RDWR);
if (dev == -1) {
syslog(LOG_ERR, "cannot open packet filter device (%m)");
goto die;
}
uid = getuid();
pw = getpwuid(uid);
if (pw == NULL) {
syslog(LOG_ERR, "cannot find user for uid %u", uid);
goto die;
}
if ((lc = login_getclass(pw->pw_class)) != NULL)
shell = login_getcapstr(lc, "shell", pw->pw_shell,
pw->pw_shell);
else
shell = pw->pw_shell;
#ifndef __FreeBSD__
login_close(lc);
#endif
if (strcmp(shell, PATH_AUTHPF_SHELL) &&
strcmp(shell, PATH_AUTHPF_SHELL_NOIP)) {
syslog(LOG_ERR, "wrong shell for user %s, uid %u",
pw->pw_name, pw->pw_uid);
#ifdef __FreeBSD__
login_close(lc);
#else
if (shell != pw->pw_shell)
free(shell);
#endif
goto die;
}
#ifdef __FreeBSD__
login_close(lc);
#else
if (shell != pw->pw_shell)
free(shell);
#endif
/*
* Paranoia, but this data _does_ come from outside authpf, and
* truncation would be bad.
*/
if (strlcpy(luser, pw->pw_name, sizeof(luser)) >= sizeof(luser)) {
syslog(LOG_ERR, "username too long: %s", pw->pw_name);
goto die;
}
if ((n = snprintf(rulesetname, sizeof(rulesetname), "%s(%ld)",
luser, (long)getpid())) < 0 || (u_int)n >= sizeof(rulesetname)) {
syslog(LOG_INFO, "%s(%ld) too large, ruleset name will be %ld",
luser, (long)getpid(), (long)getpid());
if ((n = snprintf(rulesetname, sizeof(rulesetname), "%ld",
(long)getpid())) < 0 || (u_int)n >= sizeof(rulesetname)) {
syslog(LOG_ERR, "pid too large for ruleset name");
goto die;
}
}
/* Make our entry in /var/authpf as ipaddr or username */
n = snprintf(pidfile, sizeof(pidfile), "%s/%s",
PATH_PIDFILE, user_ip ? ipsrc : luser);
if (n < 0 || (u_int)n >= sizeof(pidfile)) {
syslog(LOG_ERR, "path to pidfile too long");
goto die;
}
signal(SIGTERM, need_death);
signal(SIGINT, need_death);
signal(SIGALRM, need_death);
signal(SIGPIPE, need_death);
signal(SIGHUP, need_death);
signal(SIGQUIT, need_death);
signal(SIGTSTP, need_death);
/*
* If someone else is already using this ip, then this person
* wants to switch users - so kill the old process and exit
* as well.
*
* Note, we could print a message and tell them to log out, but the
* usual case of this is that someone has left themselves logged in,
* with the authenticated connection iconized and someone else walks
* up to use and automatically logs in before using. If this just
* gets rid of the old one silently, the new user never knows they
* could have used someone else's old authentication. If we
* tell them to log out before switching users it is an invitation
* for abuse.
*/
do {
int save_errno, otherpid = -1;
char otherluser[MAXLOGNAME];
if ((pidfd = open(pidfile, O_RDWR|O_CREAT, 0644)) == -1 ||
(pidfp = fdopen(pidfd, "r+")) == NULL) {
if (pidfd != -1)
close(pidfd);
syslog(LOG_ERR, "cannot open or create %s: %s", pidfile,
strerror(errno));
goto die;
}
if (flock(fileno(pidfp), LOCK_EX|LOCK_NB) == 0)
break;
save_errno = errno;
/* Mark our pid, and username to our file. */
rewind(pidfp);
/* 31 == MAXLOGNAME - 1 */
if (fscanf(pidfp, "%d\n%31s\n", &otherpid, otherluser) != 2)
otherpid = -1;
syslog(LOG_DEBUG, "tried to lock %s, in use by pid %d: %s",
pidfile, otherpid, strerror(save_errno));
if (otherpid > 0) {
syslog(LOG_INFO,
"killing prior auth (pid %d) of %s by user %s",
otherpid, ipsrc, otherluser);
if (kill((pid_t) otherpid, SIGTERM) == -1) {
syslog(LOG_INFO,
"could not kill process %d: (%m)",
otherpid);
}
}
/*
* We try to kill the previous process and acquire the lock
* for 10 seconds, trying once a second. if we can't after
* 10 attempts we log an error and give up.
*/
if (want_death || ++lockcnt > 10) {
if (!want_death)
syslog(LOG_ERR, "cannot kill previous authpf (pid %d)",
otherpid);
fclose(pidfp);
pidfp = NULL;
pidfd = -1;
goto dogdeath;
}
sleep(1);
/* re-open, and try again. The previous authpf process
* we killed above should unlink the file and release
* it's lock, giving us a chance to get it now
*/
fclose(pidfp);
pidfp = NULL;
pidfd = -1;
} while (1);
/* whack the group list */
gid = getegid();
if (setgroups(1, &gid) == -1) {
syslog(LOG_INFO, "setgroups: %s", strerror(errno));
do_death(0);
}
/* revoke privs */
uid = getuid();
if (setresuid(uid, uid, uid) == -1) {
syslog(LOG_INFO, "setresuid: %s", strerror(errno));
do_death(0);
}
openlog("authpf", LOG_PID | LOG_NDELAY, LOG_DAEMON);
if (!check_luser(PATH_BAN_DIR, luser) || !allowed_luser(pw)) {
syslog(LOG_INFO, "user %s prohibited", luser);
do_death(0);
}
if (read_config(config)) {
syslog(LOG_ERR, "invalid config file %s", PATH_CONFFILE);
do_death(0);
}
if (remove_stale_rulesets()) {
syslog(LOG_INFO, "error removing stale rulesets");
do_death(0);
}
/* We appear to be making headway, so actually mark our pid */
rewind(pidfp);
fprintf(pidfp, "%ld\n%s\n", (long)getpid(), luser);
fflush(pidfp);
(void) ftruncate(fileno(pidfp), ftello(pidfp));
if (change_filter(1, luser, ipsrc) == -1) {
printf("Unable to modify filters\r\n");
do_death(0);
}
if (user_ip && change_table(1, ipsrc) == -1) {
printf("Unable to modify table\r\n");
change_filter(0, luser, ipsrc);
do_death(0);
}
while (1) {
printf("\r\nHello %s. ", luser);
printf("You are authenticated from host \"%s\"\r\n", ipsrc);
setproctitle("%s@%s", luser, ipsrc);
print_message(PATH_MESSAGE);
while (1) {
sleep(10);
if (want_death)
do_death(1);
}
}
/* NOTREACHED */
dogdeath:
printf("\r\n\r\nSorry, this service is currently unavailable due to ");
printf("technical difficulties\r\n\r\n");
print_message(PATH_PROBLEM);
printf("\r\nYour authentication process (pid %ld) was unable to run\n",
(long)getpid());
sleep(180); /* them lusers read reaaaaal slow */
die:
do_death(0);
}
/*
* reads config file in PATH_CONFFILE to set optional behaviours up
*/
static int
read_config(FILE *f)
{
char buf[1024];
int i = 0;
do {
char **ap;
char *pair[4], *cp, *tp;
int len;
if (fgets(buf, sizeof(buf), f) == NULL) {
fclose(f);
return (0);
}
i++;
len = strlen(buf);
if (len == 0)
continue;
if (buf[len - 1] != '\n' && !feof(f)) {
syslog(LOG_ERR, "line %d too long in %s", i,
PATH_CONFFILE);
return (1);
}
buf[len - 1] = '\0';
for (cp = buf; *cp == ' ' || *cp == '\t'; cp++)
; /* nothing */
if (!*cp || *cp == '#' || *cp == '\n')
continue;
for (ap = pair; ap < &pair[3] &&
(*ap = strsep(&cp, "=")) != NULL; ) {
if (**ap != '\0')
ap++;
}
if (ap != &pair[2])
goto parse_error;
tp = pair[1] + strlen(pair[1]);
while ((*tp == ' ' || *tp == '\t') && tp >= pair[1])
*tp-- = '\0';
if (strcasecmp(pair[0], "anchor") == 0) {
if (!pair[1][0] || strlcpy(anchorname, pair[1],
sizeof(anchorname)) >= sizeof(anchorname))
goto parse_error;
}
if (strcasecmp(pair[0], "table") == 0) {
if (!pair[1][0] || strlcpy(tablename, pair[1],
sizeof(tablename)) >= sizeof(tablename))
goto parse_error;
}
} while (!feof(f) && !ferror(f));
fclose(f);
return (0);
parse_error:
fclose(f);
syslog(LOG_ERR, "parse error, line %d of %s", i, PATH_CONFFILE);
return (1);
}
/*
* splatter a file to stdout - max line length of 1024,
* used for spitting message files at users to tell them
* they've been bad or we're unavailable.
*/
static void
print_message(const char *filename)
{
char buf[1024];
FILE *f;
if ((f = fopen(filename, "r")) == NULL)
return; /* fail silently, we don't care if it isn't there */
do {
if (fgets(buf, sizeof(buf), f) == NULL) {
fflush(stdout);
fclose(f);
return;
}
} while (fputs(buf, stdout) != EOF && !feof(f));
fflush(stdout);
fclose(f);
}
/*
* allowed_luser checks to see if user "luser" is allowed to
* use this gateway by virtue of being listed in an allowed
* users file, namely /etc/authpf/authpf.allow .
* Users may be listed by <username>, %<group>, or @<login_class>.
*
* If /etc/authpf/authpf.allow does not exist, then we assume that
* all users who are allowed in by sshd(8) are permitted to
* use this gateway. If /etc/authpf/authpf.allow does exist, then a
* user must be listed if the connection is to continue, else
* the session terminates in the same manner as being banned.
*/
static int
allowed_luser(struct passwd *pw)
{
char *buf,*lbuf;
int matched;
size_t len;
FILE *f;
if ((f = fopen(PATH_ALLOWFILE, "r")) == NULL) {
if (errno == ENOENT) {
/*
* allowfile doesn't exist, thus this gateway
* isn't restricted to certain users...
*/
return (1);
}
/*
* luser may in fact be allowed, but we can't open
* the file even though it's there. probably a config
* problem.
*/
syslog(LOG_ERR, "cannot open allowed users file %s (%s)",
PATH_ALLOWFILE, strerror(errno));
return (0);
} else {
/*
* /etc/authpf/authpf.allow exists, thus we do a linear
* search to see if they are allowed.
* also, if username "*" exists, then this is a
* "public" gateway, such as it is, so let
* everyone use it.
*/
int gl_init = 0, ngroups = NGROUPS + 1;
gid_t groups[NGROUPS + 1];
lbuf = NULL;
matched = 0;
while ((buf = fgetln(f, &len))) {
if (buf[len - 1] == '\n')
buf[len - 1] = '\0';
else {
if ((lbuf = (char *)malloc(len + 1)) == NULL)
err(1, NULL);
memcpy(lbuf, buf, len);
lbuf[len] = '\0';
buf = lbuf;
}
if (buf[0] == '@') {
/* check login class */
if (strcmp(pw->pw_class, buf + 1) == 0)
matched++;
} else if (buf[0] == '%') {
/* check group membership */
int cnt;
struct group *group;
if ((group = getgrnam(buf + 1)) == NULL) {
syslog(LOG_ERR,
"invalid group '%s' in %s (%s)",
buf + 1, PATH_ALLOWFILE,
strerror(errno));
return (0);
}
if (!gl_init) {
(void) getgrouplist(pw->pw_name,
pw->pw_gid, groups, &ngroups);
gl_init++;
}
for ( cnt = 0; cnt < ngroups; cnt++) {
if (group->gr_gid == groups[cnt]) {
matched++;
break;
}
}
} else {
/* check username and wildcard */
matched = strcmp(pw->pw_name, buf) == 0 ||
strcmp("*", buf) == 0;
}
if (lbuf != NULL) {
free(lbuf);
lbuf = NULL;
}
if (matched)
return (1); /* matched an allowed user/group */
}
syslog(LOG_INFO, "denied access to %s: not listed in %s",
pw->pw_name, PATH_ALLOWFILE);
/* reuse buf */
sprintf(buf, "%s", "\n\nSorry, you are not allowed to use this facility!\n");
fputs(buf, stdout);
}
fflush(stdout);
return (0);
}
/*
* check_luser checks to see if user "luser" has been banned
* from using us by virtue of having an file of the same name
* in the "luserdir" directory.
*
* If the user has been banned, we copy the contents of the file
* to the user's screen. (useful for telling the user what to
* do to get un-banned, or just to tell them they aren't
* going to be un-banned.)
*/
static int
check_luser(const char *luserdir, char *l_user)
{
FILE *f;
int n;
char tmp[MAXPATHLEN];
n = snprintf(tmp, sizeof(tmp), "%s/%s", luserdir, l_user);
if (n < 0 || (u_int)n >= sizeof(tmp)) {
syslog(LOG_ERR, "provided banned directory line too long (%s)",
luserdir);
return (0);
}
if ((f = fopen(tmp, "r")) == NULL) {
if (errno == ENOENT) {
/*
* file or dir doesn't exist, so therefore
* this luser isn't banned.. all is well
*/
return (1);
} else {
/*
* luser may in fact be banned, but we can't open the
* file even though it's there. probably a config
* problem.
*/
syslog(LOG_ERR, "cannot open banned file %s (%s)",
tmp, strerror(errno));
return (0);
}
} else {
/*
* luser is banned - spit the file at them to
* tell what they can do and where they can go.
*/
syslog(LOG_INFO, "denied access to %s: %s exists",
l_user, tmp);
/* reuse tmp */
strlcpy(tmp, "\n\n-**- Sorry, you have been banned! -**-\n\n",
sizeof(tmp));
while (fputs(tmp, stdout) != EOF && !feof(f)) {
if (fgets(tmp, sizeof(tmp), f) == NULL) {
fflush(stdout);
fclose(f);
return (0);
}
}
fclose(f);
}
fflush(stdout);
return (0);
}
/*
* Search for rulesets left by other authpf processes (either because they
* died ungracefully or were terminated) and remove them.
*/
static int
remove_stale_rulesets(void)
{
struct pfioc_ruleset prs;
u_int32_t nr;
memset(&prs, 0, sizeof(prs));
strlcpy(prs.path, anchorname, sizeof(prs.path));
if (ioctl(dev, DIOCGETRULESETS, &prs)) {
if (errno == EINVAL)
return (0);
else
return (1);
}
nr = prs.nr;
while (nr) {
char *s, *t;
pid_t pid;
prs.nr = nr - 1;
if (ioctl(dev, DIOCGETRULESET, &prs))
return (1);
errno = 0;
if ((t = strchr(prs.name, '(')) == NULL)
t = prs.name;
else
t++;
pid = strtoul(t, &s, 10);
if (!prs.name[0] || errno ||
(*s && (t == prs.name || *s != ')')))
return (1);
if ((kill(pid, 0) && errno != EPERM) || pid == getpid()) {
if (recursive_ruleset_purge(anchorname, prs.name))
return (1);
}
nr--;
}
return (0);
}
static int
recursive_ruleset_purge(char *an, char *rs)
{
struct pfioc_trans_e *t_e = NULL;
struct pfioc_trans *t = NULL;
struct pfioc_ruleset *prs = NULL;
int i;
/* purge rules */
errno = 0;
if ((t = calloc(1, sizeof(struct pfioc_trans))) == NULL)
goto no_mem;
if ((t_e = calloc(PF_RULESET_MAX+1,
sizeof(struct pfioc_trans_e))) == NULL)
goto no_mem;
t->size = PF_RULESET_MAX+1;
t->esize = sizeof(struct pfioc_trans_e);
t->array = t_e;
for (i = 0; i < PF_RULESET_MAX+1; ++i) {
t_e[i].rs_num = i;
snprintf(t_e[i].anchor, sizeof(t_e[i].anchor), "%s/%s", an, rs);
}
t_e[PF_RULESET_MAX].rs_num = PF_RULESET_TABLE;
if ((ioctl(dev, DIOCXBEGIN, t) ||
ioctl(dev, DIOCXCOMMIT, t)) &&
errno != EINVAL)
goto cleanup;
/* purge any children */
if ((prs = calloc(1, sizeof(struct pfioc_ruleset))) == NULL)
goto no_mem;
snprintf(prs->path, sizeof(prs->path), "%s/%s", an, rs);
if (ioctl(dev, DIOCGETRULESETS, prs)) {
if (errno != EINVAL)
goto cleanup;
errno = 0;
} else {
int nr = prs->nr;
while (nr) {
prs->nr = 0;
if (ioctl(dev, DIOCGETRULESET, prs))
goto cleanup;
if (recursive_ruleset_purge(prs->path, prs->name))
goto cleanup;
nr--;
}
}
no_mem:
if (errno == ENOMEM)
syslog(LOG_ERR, "calloc failed");
cleanup:
free(t);
free(t_e);
free(prs);
return (errno);
}
/*
* Add/remove filter entries for user "luser" from ip "ipsrc"
*/
static int
change_filter(int add, const char *l_user, const char *ip_src)
{
char *fdpath = NULL, *userstr = NULL, *ipstr = NULL;
char *rsn = NULL, *fn = NULL;
pid_t pid;
gid_t gid;
int s;
if (add) {
struct stat sb;
char *pargv[13] = {
"pfctl", "-p", "/dev/pf", "-q", "-a", "anchor/ruleset",
"-D", "user_id=X", "-D", "user_ip=X", "-f", "file", NULL
};
if (l_user == NULL || !l_user[0] || ip_src == NULL || !ip_src[0]) {
syslog(LOG_ERR, "invalid luser/ipsrc");
goto error;
}
if (asprintf(&rsn, "%s/%s", anchorname, rulesetname) == -1)
goto no_mem;
if (asprintf(&fdpath, "/dev/fd/%d", dev) == -1)
goto no_mem;
if (asprintf(&ipstr, "user_ip=%s", ip_src) == -1)
goto no_mem;
if (asprintf(&userstr, "user_id=%s", l_user) == -1)
goto no_mem;
if (asprintf(&fn, "%s/%s/authpf.rules",
PATH_USER_DIR, l_user) == -1)
goto no_mem;
if (stat(fn, &sb) == -1) {
free(fn);
if ((fn = strdup(PATH_PFRULES)) == NULL)
goto no_mem;
}
pargv[2] = fdpath;
pargv[5] = rsn;
pargv[7] = userstr;
if (user_ip) {
pargv[9] = ipstr;
pargv[11] = fn;
} else {
pargv[8] = "-f";
pargv[9] = fn;
pargv[10] = NULL;
}
switch (pid = fork()) {
case -1:
syslog(LOG_ERR, "fork failed");
goto error;
case 0:
/* revoke group privs before exec */
gid = getgid();
if (setregid(gid, gid) == -1) {
err(1, "setregid");
}
execvp(PATH_PFCTL, pargv);
warn("exec of %s failed", PATH_PFCTL);
_exit(1);
}
/* parent */
waitpid(pid, &s, 0);
if (s != 0) {
syslog(LOG_ERR, "pfctl exited abnormally");
goto error;
}
gettimeofday(&Tstart, NULL);
syslog(LOG_INFO, "allowing %s, user %s", ip_src, l_user);
} else {
remove_stale_rulesets();
gettimeofday(&Tend, NULL);
syslog(LOG_INFO, "removed %s, user %s - duration %ju seconds",
ip_src, l_user, (uintmax_t)(Tend.tv_sec - Tstart.tv_sec));
}
return (0);
no_mem:
syslog(LOG_ERR, "malloc failed");
error:
free(fdpath);
free(rsn);
free(userstr);
free(ipstr);
free(fn);
return (-1);
}
/*
* Add/remove this IP from the "authpf_users" table.
*/
static int
change_table(int add, const char *ip_src)
{
struct pfioc_table io;
struct pfr_addr addr;
bzero(&io, sizeof(io));
strlcpy(io.pfrio_table.pfrt_name, tablename,
sizeof(io.pfrio_table.pfrt_name));
io.pfrio_buffer = &addr;
io.pfrio_esize = sizeof(addr);
io.pfrio_size = 1;
bzero(&addr, sizeof(addr));
if (ip_src == NULL || !ip_src[0])
return (-1);
if (inet_pton(AF_INET, ip_src, &addr.pfra_ip4addr) == 1) {
addr.pfra_af = AF_INET;
addr.pfra_net = 32;
} else if (inet_pton(AF_INET6, ip_src, &addr.pfra_ip6addr) == 1) {
addr.pfra_af = AF_INET6;
addr.pfra_net = 128;
} else {
syslog(LOG_ERR, "invalid ipsrc");
return (-1);
}
if (ioctl(dev, add ? DIOCRADDADDRS : DIOCRDELADDRS, &io) &&
errno != ESRCH) {
syslog(LOG_ERR, "cannot %s %s from table %s: %s",
add ? "add" : "remove", ip_src, tablename,
strerror(errno));
return (-1);
}
return (0);
}
/*
* This is to kill off states that would otherwise be left behind stateful
* rules. This means we don't need to allow in more traffic than we really
* want to, since we don't have to worry about any luser sessions lasting
* longer than their ssh session. This function is based on
* pfctl_kill_states from pfctl.
*/
static void
authpf_kill_states(void)
{
struct pfioc_state_kill psk;
struct pf_addr target;
memset(&psk, 0, sizeof(psk));
memset(&target, 0, sizeof(target));
if (inet_pton(AF_INET, ipsrc, &target.v4) == 1)
psk.psk_af = AF_INET;
else if (inet_pton(AF_INET6, ipsrc, &target.v6) == 1)
psk.psk_af = AF_INET6;
else {
syslog(LOG_ERR, "inet_pton(%s) failed", ipsrc);
return;
}
/* Kill all states from ipsrc */
memcpy(&psk.psk_src.addr.v.a.addr, &target,
sizeof(psk.psk_src.addr.v.a.addr));
memset(&psk.psk_src.addr.v.a.mask, 0xff,
sizeof(psk.psk_src.addr.v.a.mask));
if (ioctl(dev, DIOCKILLSTATES, &psk))
syslog(LOG_ERR, "DIOCKILLSTATES failed (%m)");
/* Kill all states to ipsrc */
memset(&psk.psk_src, 0, sizeof(psk.psk_src));
memcpy(&psk.psk_dst.addr.v.a.addr, &target,
sizeof(psk.psk_dst.addr.v.a.addr));
memset(&psk.psk_dst.addr.v.a.mask, 0xff,
sizeof(psk.psk_dst.addr.v.a.mask));
if (ioctl(dev, DIOCKILLSTATES, &psk))
syslog(LOG_ERR, "DIOCKILLSTATES failed (%m)");
}
/* signal handler that makes us go away properly */
static void
need_death(int signo __unused)
{
want_death = 1;
}
/*
* function that removes our stuff when we go away.
*/
#ifdef __FreeBSD__
static __dead2 void
#else
static __dead void
#endif
do_death(int active)
{
int ret = 0;
if (active) {
change_filter(0, luser, ipsrc);
if (user_ip) {
change_table(0, ipsrc);
authpf_kill_states();
}
}
if (pidfile[0] && pidfd != -1)
if (unlink(pidfile) == -1)
syslog(LOG_ERR, "cannot unlink %s (%m)", pidfile);
exit(ret);
}
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