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-rw-r--r--pf.c711
1 files changed, 711 insertions, 0 deletions
diff --git a/pf.c b/pf.c
new file mode 100644
index 0000000..6b4cba4
--- /dev/null
+++ b/pf.c
@@ -0,0 +1,711 @@
+/*
+ * 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);
+ 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
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-15 22:15:04 +0000