/*
* OpenVPN -- An application to securely tunnel IP networks
* over a single TCP/UDP port, with support for SSL/TLS-based
* session authentication and key exchange,
* packet encryption, packet authentication, and
* packet compression.
*
* Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <sales@openvpn.net>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program (see the file COPYING included with this
* distribution); if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/* packet filter functions */
#include "syshead.h"
#if defined(ENABLE_PF)
#include "init.h"
#include "memdbg.h"
#include "pf-inline.h"
static void
pf_destroy (struct pf_set *pfs)
{
if (pfs)
{
if (pfs->cns.hash_table)
hash_free (pfs->cns.hash_table);
{
struct pf_cn_elem *l = pfs->cns.list;
while (l)
{
struct pf_cn_elem *next = l->next;
free (l->rule.cn);
free (l);
l = next;
}
}
{
struct pf_subnet *l = pfs->sns.list;
while (l)
{
struct pf_subnet *next = l->next;
free (l);
l = next;
}
}
free (pfs);
}
}
static bool
add_client (const char *line, const char *prefix, const int line_num, struct pf_cn_elem ***next, const bool exclude)
{
struct pf_cn_elem *e;
ALLOC_OBJ_CLEAR (e, struct pf_cn_elem);
e->rule.exclude = exclude;
e->rule.cn = string_alloc (line, NULL);
**next = e;
*next = &e->next;
return true;
}
static bool
add_subnet (const char *line, const char *prefix, const int line_num, struct pf_subnet ***next, const bool exclude)
{
struct in_addr network;
in_addr_t netmask = 0;
if (strcmp (line, "unknown"))
{
int netbits = 32;
char *div = strchr (line, '/');
if (div)
{
*div++ = '\0';
if (sscanf (div, "%d", &netbits) != 1)
{
msg (D_PF_INFO, "PF: %s/%d: bad '/n' subnet specifier: '%s'", prefix, line_num, div);
return false;
}
if (netbits < 0 || netbits > 32)
{
msg (D_PF_INFO, "PF: %s/%d: bad '/n' subnet specifier: must be between 0 and 32: '%s'", prefix, line_num, div);
return false;
}
}
if (openvpn_inet_aton (line, &network) != OIA_IP)
{
msg (D_PF_INFO, "PF: %s/%d: bad network address: '%s'", prefix, line_num, line);
return false;
}
netmask = netbits_to_netmask (netbits);
if ((network.s_addr & htonl (netmask)) != network.s_addr)
{
network.s_addr &= htonl (netmask);
msg (M_WARN, "WARNING: PF: %s/%d: incorrect subnet %s/%d changed to %s/%d", prefix, line_num, line, netbits, inet_ntoa (network), netbits);
}
}
else
{
/* match special "unknown" tag for addresses unrecognized by mroute */
network.s_addr = htonl(0);
netmask = ~0;
}
{
struct pf_subnet *e;
ALLOC_OBJ_CLEAR (e, struct pf_subnet);
e->rule.exclude = exclude;
e->rule.network = ntohl (network.s_addr);
e->rule.netmask = netmask;
**next = e;
*next = &e->next;
return true;
}
}
static uint32_t
cn_hash_function (const void *key, uint32_t iv)
{
return hash_func ((uint8_t *)key, strlen ((char *)key) + 1, iv);
}
static bool
cn_compare_function (const void *key1, const void *key2)
{
return !strcmp((const char *)key1, (const char *)key2);
}
static bool
genhash (struct pf_cn_set *cns, const char *prefix, const int n_clients)
{
struct pf_cn_elem *e;
bool status = true;
int n_buckets = n_clients;
if (n_buckets < 16)
n_buckets = 16;
cns->hash_table = hash_init (n_buckets, 0, cn_hash_function, cn_compare_function);
for (e = cns->list; e != NULL; e = e->next)
{
if (!hash_add (cns->hash_table, e->rule.cn, &e->rule, false))
{
msg (D_PF_INFO, "PF: %s: duplicate common name in [clients] section: '%s'", prefix, e->rule.cn);
status = false;
}
}
return status;
}
static struct pf_set *
pf_init (const struct buffer_list *bl, const char *prefix, const bool allow_kill)
{
# define MODE_UNDEF 0
# define MODE_CLIENTS 1
# define MODE_SUBNETS 2
int mode = MODE_UNDEF;
int line_num = 0;
int n_clients = 0;
int n_subnets = 0;
int n_errors = 0;
struct pf_set *pfs = NULL;
char line[PF_MAX_LINE_LEN];
ALLOC_OBJ_CLEAR (pfs, struct pf_set);
if (bl)
{
struct pf_cn_elem **cl = &pfs->cns.list;
struct pf_subnet **sl = &pfs->sns.list;
struct buffer_entry *be;
for (be = bl->head; be != NULL; be = be->next)
{
++line_num;
strncpynt (line, BSTR(&be->buf), sizeof(line));
rm_trailing_chars (line, "\r\n\t ");
if (line[0] == '\0' || line[0] == '#')
;
else if (line[0] == '+' || line[0] == '-')
{
bool exclude = (line[0] == '-');
if (line[1] =='\0')
{
msg (D_PF_INFO, "PF: %s/%d: no data after +/-: '%s'", prefix, line_num, line);
++n_errors;
}
else if (mode == MODE_CLIENTS)
{
if (add_client (&line[1], prefix, line_num, &cl, exclude))
++n_clients;
else
++n_errors;
}
else if (mode == MODE_SUBNETS)
{
if (add_subnet (&line[1], prefix, line_num, &sl, exclude))
++n_subnets;
else
++n_errors;
}
else if (mode == MODE_UNDEF)
;
else
{
ASSERT (0);
}
}
else if (line[0] == '[')
{
if (!strcasecmp (line, "[clients accept]"))
{
mode = MODE_CLIENTS;
pfs->cns.default_allow = true;
}
else if (!strcasecmp (line, "[clients drop]"))
{
mode = MODE_CLIENTS;
pfs->cns.default_allow = false;
}
else if (!strcasecmp (line, "[subnets accept]"))
{
mode = MODE_SUBNETS;
pfs->sns.default_allow = true;
}
else if (!strcasecmp (line, "[subnets drop]"))
{
mode = MODE_SUBNETS;
pfs->sns.default_allow = false;
}
else if (!strcasecmp (line, "[end]"))
goto done;
else if (allow_kill && !strcasecmp (line, "[kill]"))
goto kill;
else
{
mode = MODE_UNDEF;
msg (D_PF_INFO, "PF: %s/%d unknown tag: '%s'", prefix, line_num, line);
++n_errors;
}
}
else
{
msg (D_PF_INFO, "PF: %s/%d line must begin with '+', '-', or '[' : '%s'", prefix, line_num, line);
++n_errors;
}
}
++n_errors;
msg (D_PF_INFO, "PF: %s: missing [end]", prefix);
}
else
{
msg (D_PF_INFO, "PF: %s: cannot open", prefix);
++n_errors;
}
done:
if (bl)
{
if (!n_errors)
{
if (!genhash (&pfs->cns, prefix, n_clients))
++n_errors;
}
if (n_errors)
msg (D_PF_INFO, "PF: %s rejected due to %d error(s)", prefix, n_errors);
}
if (n_errors)
{
pf_destroy (pfs);
pfs = NULL;
}
return pfs;
kill:
pf_destroy (pfs);
ALLOC_OBJ_CLEAR (pfs, struct pf_set);
pfs->kill = true;
return pfs;
}
#ifdef PLUGIN_PF
static struct pf_set *
pf_init_from_file (const char *fn)
{
struct buffer_list *bl = buffer_list_file (fn, PF_MAX_LINE_LEN);
if (bl)
{
struct pf_set *pfs = pf_init (bl, fn, true);
buffer_list_free (bl);
return pfs;
}
else
{
msg (D_PF_INFO|M_ERRNO, "PF: %s: cannot open", fn);
return NULL;
}
}
#endif
#ifdef ENABLE_DEBUG
static const char *
drop_accept (const bool accept)
{
return accept ? "ACCEPT" : "DROP";
}
static const char *
pct_name (const int type)
{
switch (type)
{
case PCT_SRC:
return "SRC";
case PCT_DEST:
return "DEST";
default:
return "???";
}
}
static void
pf_cn_test_print (const char *prefix,
const int type,
const char *prefix2,
const char *cn,
const bool allow,
const struct pf_cn *rule)
{
if (rule)
{
dmsg (D_PF_DEBUG, "PF: %s/%s/%s %s %s rule=[%s %s]",
prefix, prefix2, pct_name (type),
cn, drop_accept (allow),
rule->cn, drop_accept (!rule->exclude));
}
else
{
dmsg (D_PF_DEBUG, "PF: %s/%s/%s %s %s",
prefix, prefix2, pct_name (type),
cn, drop_accept (allow));
}
}
static void
pf_addr_test_print (const char *prefix,
const char *prefix2,
const struct context *src,
const struct mroute_addr *dest,
const bool allow,
const struct ipv4_subnet *rule)
{
struct gc_arena gc = gc_new ();
if (rule)
{
dmsg (D_PF_DEBUG, "PF: %s/%s %s %s %s rule=[%s/%s %s]",
prefix,
prefix2,
tls_common_name (src->c2.tls_multi, false),
mroute_addr_print_ex (dest, MAPF_SHOW_ARP, &gc),
drop_accept (allow),
print_in_addr_t (rule->network, 0, &gc),
print_in_addr_t (rule->netmask, 0, &gc),
drop_accept (!rule->exclude));
}
else
{
dmsg (D_PF_DEBUG, "PF: %s/%s %s %s %s",
prefix,
prefix2,
tls_common_name (src->c2.tls_multi, false),
mroute_addr_print_ex (dest, MAPF_SHOW_ARP, &gc),
drop_accept (allow));
}
gc_free (&gc);
}
#endif
static inline struct pf_cn *
lookup_cn_rule (struct hash *h, const char *cn, const uint32_t cn_hash)
{
struct hash_element *he = hash_lookup_fast (h, hash_bucket (h, cn_hash), cn, cn_hash);
if (he)
return (struct pf_cn *) he->value;
else
return NULL;
}
bool
pf_cn_test (struct pf_set *pfs, const struct tls_multi *tm, const int type, const char *prefix)
{
if (!pfs->kill)
{
const char *cn;
uint32_t cn_hash;
if (tls_common_name_hash (tm, &cn, &cn_hash))
{
const struct pf_cn *rule = lookup_cn_rule (pfs->cns.hash_table, cn, cn_hash);
if (rule)
{
#ifdef ENABLE_DEBUG
if (check_debug_level (D_PF_DEBUG))
pf_cn_test_print ("PF_CN_MATCH", type, prefix, cn, !rule->exclude, rule);
#endif
if (!rule->exclude)
return true;
else
return false;
}
else
{
#ifdef ENABLE_DEBUG
if (check_debug_level (D_PF_DEBUG))
pf_cn_test_print ("PF_CN_DEFAULT", type, prefix, cn, pfs->cns.default_allow, NULL);
#endif
if (pfs->cns.default_allow)
return true;
else
return false;
}
}
}
#ifdef ENABLE_DEBUG
if (check_debug_level (D_PF_DEBUG))
pf_cn_test_print ("PF_CN_FAULT", type, prefix, tls_common_name (tm, false), false, NULL);
#endif
return false;
}
bool
pf_addr_test_dowork (const struct context *src, const struct mroute_addr *dest, const char *prefix)
{
struct pf_set *pfs = src->c2.pf.pfs;
if (pfs && !pfs->kill)
{
const in_addr_t addr = in_addr_t_from_mroute_addr (dest);
const struct pf_subnet *se = pfs->sns.list;
while (se)
{
if ((addr & se->rule.netmask) == se->rule.network)
{
#ifdef ENABLE_DEBUG
if (check_debug_level (D_PF_DEBUG))
pf_addr_test_print ("PF_ADDR_MATCH", prefix, src, dest, !se->rule.exclude, &se->rule);
#endif
return !se->rule.exclude;
}
se = se->next;
}
#ifdef ENABLE_DEBUG
if (check_debug_level (D_PF_DEBUG))
pf_addr_test_print ("PF_ADDR_DEFAULT", prefix, src, dest, pfs->sns.default_allow, NULL);
#endif
return pfs->sns.default_allow;
}
else
{
#ifdef ENABLE_DEBUG
if (check_debug_level (D_PF_DEBUG))
pf_addr_test_print ("PF_ADDR_FAULT", prefix, src, dest, false, NULL);
#endif
return false;
}
}
#ifdef PLUGIN_PF
void
pf_check_reload (struct context *c)
{
const int slow_wakeup = 15;
const int fast_wakeup = 1;
const int wakeup_transition = 60;
bool reloaded = false;
if (c->c2.pf.enabled
&& c->c2.pf.filename
&& event_timeout_trigger (&c->c2.pf.reload, &c->c2.timeval, ETT_DEFAULT))
{
struct stat s;
if (!stat (c->c2.pf.filename, &s))
{
if (s.st_mtime > c->c2.pf.file_last_mod)
{
struct pf_set *pfs = pf_init_from_file (c->c2.pf.filename);
if (pfs)
{
if (c->c2.pf.pfs)
pf_destroy (c->c2.pf.pfs);
c->c2.pf.pfs = pfs;
reloaded = true;
if (pf_kill_test (pfs))
{
c->sig->signal_received = SIGTERM;
c->sig->signal_text = "pf-kill";
}
}
c->c2.pf.file_last_mod = s.st_mtime;
}
}
{
int wakeup = slow_wakeup;
if (!c->c2.pf.pfs && c->c2.pf.n_check_reload < wakeup_transition)
wakeup = fast_wakeup;
event_timeout_init (&c->c2.pf.reload, wakeup, now);
reset_coarse_timers (c);
c->c2.pf.n_check_reload++;
}
}
#ifdef ENABLE_DEBUG
if (reloaded && check_debug_level (D_PF_DEBUG))
pf_context_print (&c->c2.pf, "pf_check_reload", D_PF_DEBUG);
#endif
}
#endif
#ifdef MANAGEMENT_PF
bool
pf_load_from_buffer_list (struct context *c, const struct buffer_list *config)
{
struct pf_set *pfs = pf_init (config, "[SERVER-PF]", false);
if (pfs)
{
if (c->c2.pf.pfs)
pf_destroy (c->c2.pf.pfs);
c->c2.pf.pfs = pfs;
return true;
}
else
return false;
}
#endif
void
pf_init_context (struct context *c)
{
struct gc_arena gc = gc_new ();
#ifdef PLUGIN_PF
if (plugin_defined (c->plugins, OPENVPN_PLUGIN_ENABLE_PF))
{
const char *pf_file = create_temp_file (c->options.tmp_dir, "pf", &gc);
if( pf_file ) {
setenv_str (c->c2.es, "pf_file", pf_file);
if (plugin_call (c->plugins, OPENVPN_PLUGIN_ENABLE_PF, NULL, NULL, c->c2.es) == OPENVPN_PLUGIN_FUNC_SUCCESS)
{
event_timeout_init (&c->c2.pf.reload, 1, now);
c->c2.pf.filename = string_alloc (pf_file, NULL);
c->c2.pf.enabled = true;
#ifdef ENABLE_DEBUG
if (check_debug_level (D_PF_DEBUG))
pf_context_print (&c->c2.pf, "pf_init_context#1", D_PF_DEBUG);
#endif
}
else
{
msg (M_WARN, "WARNING: OPENVPN_PLUGIN_ENABLE_PF disabled");
}
}
}
#endif
#ifdef MANAGEMENT_PF
if (!c->c2.pf.enabled && management_enable_pf (management))
{
c->c2.pf.enabled = true;
#ifdef ENABLE_DEBUG
if (check_debug_level (D_PF_DEBUG))
pf_context_print (&c->c2.pf, "pf_init_context#2", D_PF_DEBUG);
#endif
}
#endif
gc_free (&gc);
}
void
pf_destroy_context (struct pf_context *pfc)
{
#ifdef PLUGIN_PF
if (pfc->filename)
{
delete_file (pfc->filename);
free (pfc->filename);
}
#endif
if (pfc->pfs)
pf_destroy (pfc->pfs);
}
#ifdef ENABLE_DEBUG
static void
pf_subnet_set_print (const struct pf_subnet_set *s, const int lev)
{
struct gc_arena gc = gc_new ();
if (s)
{
struct pf_subnet *e;
msg (lev, " ----- struct pf_subnet_set -----");
msg (lev, " default_allow=%s", drop_accept (s->default_allow));
for (e = s->list; e != NULL; e = e->next)
{
msg (lev, " %s/%s %s",
print_in_addr_t (e->rule.network, 0, &gc),
print_in_addr_t (e->rule.netmask, 0, &gc),
drop_accept (!e->rule.exclude));
}
}
gc_free (&gc);
}
static void
pf_cn_set_print (const struct pf_cn_set *s, const int lev)
{
if (s)
{
struct hash_iterator hi;
struct hash_element *he;
msg (lev, " ----- struct pf_cn_set -----");
msg (lev, " default_allow=%s", drop_accept (s->default_allow));
if (s->hash_table)
{
hash_iterator_init (s->hash_table, &hi, false);
while ((he = hash_iterator_next (&hi)))
{
struct pf_cn *e = (struct pf_cn *)he->value;
msg (lev, " %s %s",
e->cn,
drop_accept (!e->exclude));
}
msg (lev, " ----------");
{
struct pf_cn_elem *ce;
for (ce = s->list; ce != NULL; ce = ce->next)
{
struct pf_cn *e = lookup_cn_rule (s->hash_table, ce->rule.cn, cn_hash_function (ce->rule.cn, 0));
if (e)
{
msg (lev, " %s %s",
e->cn,
drop_accept (!e->exclude));
}
else
{
msg (lev, " %s LOOKUP FAILED", ce->rule.cn);
}
}
}
}
}
}
static void
pf_set_print (const struct pf_set *pfs, const int lev)
{
if (pfs)
{
msg (lev, " ----- struct pf_set -----");
msg (lev, " kill=%d", pfs->kill);
pf_subnet_set_print (&pfs->sns, lev);
pf_cn_set_print (&pfs->cns, lev);
}
}
void
pf_context_print (const struct pf_context *pfc, const char *prefix, const int lev)
{
msg (lev, "----- %s : struct pf_context -----", prefix);
if (pfc)
{
msg (lev, "enabled=%d", pfc->enabled);
#ifdef PLUGIN_PF
msg (lev, "filename='%s'", np(pfc->filename));
msg (lev, "file_last_mod=%u", (unsigned int)pfc->file_last_mod);
msg (lev, "n_check_reload=%u", pfc->n_check_reload);
msg (lev, "reload=[%d,%u,%u]", pfc->reload.defined, pfc->reload.n, (unsigned int)pfc->reload.last);
#endif
pf_set_print (pfc->pfs, lev);
}
msg (lev, "--------------------");
}
#endif
#endif