--- /dev/null
+/*
+ * charybdis: A slightly useful ircd.
+ * blacklist.c: Manages DNS blacklist entries and lookups
+ *
+ * Copyright (C) 2006-2011 charybdis development team
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * 3. The name of the author may not be used to endorse or promote products
+ * derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
+ * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/* Originally written for charybdis circa 2006 (by nenolod?).
+ * Tweaked for authd. Some functions and structs renamed. Public/private
+ * interfaces have been shifted around. Some code has been cleaned up too.
+ * -- Elizafox 24 March 2016
+ */
+
+#include "authd.h"
+#include "provider.h"
+#include "stdinc.h"
+#include "dns.h"
+
+typedef enum filter_t
+{
+ FILTER_ALL = 1,
+ FILTER_LAST = 2,
+} filter_t;
+
+/* Blacklist accepted IP types */
+#define IPTYPE_IPV4 1
+#define IPTYPE_IPV6 2
+
+/* A configured DNSBL */
+struct blacklist
+{
+ char host[IRCD_RES_HOSTLEN + 1];
+ char reason[BUFSIZE]; /* Reason template (ircd fills in the blanks) */
+ unsigned char iptype; /* IP types supported */
+ rb_dlink_list filters; /* Filters for queries */
+
+ bool delete; /* If true delete when no clients */
+ int refcount; /* When 0 and delete is set, remove this blacklist */
+
+ time_t lastwarning; /* Last warning about garbage replies sent */
+};
+
+/* A lookup in progress for a particular DNSBL for a particular client */
+struct blacklist_lookup
+{
+ struct blacklist *bl; /* Blacklist we're checking */
+ struct auth_client *auth; /* Client */
+ struct dns_query *query; /* DNS query pointer */
+
+ rb_dlink_node node;
+};
+
+/* A blacklist filter */
+struct blacklist_filter
+{
+ filter_t type; /* Type of filter */
+ char filterstr[HOSTIPLEN]; /* The filter itself */
+
+ rb_dlink_node node;
+};
+
+/* Blacklist user data attached to auth_client instance */
+struct blacklist_user
+{
+ rb_dlink_list queries; /* Blacklist queries in flight */
+ time_t timeout; /* When this times out */
+};
+
+/* public interfaces */
+static bool blacklists_init(void);
+static void blacklists_destroy(void);
+
+static bool blacklists_start(struct auth_client *);
+static void blacklists_cancel(struct auth_client *);
+
+/* private interfaces */
+static void unref_blacklist(struct blacklist *);
+static struct blacklist *new_blacklist(char *, char *, bool, bool, rb_dlink_list *);
+static struct blacklist *find_blacklist(char *);
+static bool blacklist_check_reply(struct blacklist_lookup *, const char *);
+static void blacklist_dns_callback(const char *, bool, query_type, void *);
+static void initiate_blacklist_dnsquery(struct blacklist *, struct auth_client *);
+static void timeout_blacklist_queries_event(void *);
+
+/* Variables */
+static rb_dlink_list blacklist_list = { NULL, NULL, 0 };
+static struct ev_entry *timeout_ev;
+static EVH timeout_blacklists;
+static int blacklist_timeout = 15;
+
+/* private interfaces */
+
+static void
+unref_blacklist(struct blacklist *bl)
+{
+ rb_dlink_node *ptr, *nptr;
+
+ bl->refcount--;
+ if (bl->delete && bl->refcount <= 0)
+ {
+ RB_DLINK_FOREACH_SAFE(ptr, nptr, bl->filters.head)
+ {
+ rb_dlinkDelete(ptr, &bl->filters);
+ rb_free(ptr);
+ }
+
+ rb_dlinkFindDestroy(bl, &blacklist_list);
+ rb_free(bl);
+ }
+}
+
+static struct blacklist *
+new_blacklist(char *name, char *reason, bool ipv4, bool ipv6, rb_dlink_list *filters)
+{
+ struct blacklist *bl;
+
+ if (name == NULL || reason == NULL || !(ipv4 || ipv6))
+ return NULL;
+
+ if((bl = find_blacklist(name)) == NULL)
+ {
+ bl = rb_malloc(sizeof(struct blacklist));
+ rb_dlinkAddAlloc(bl, &blacklist_list);
+ }
+ else
+ bl->delete = false;
+
+ rb_strlcpy(bl->host, name, IRCD_RES_HOSTLEN + 1);
+ rb_strlcpy(bl->reason, reason, BUFSIZE);
+ if(ipv4)
+ bl->iptype |= IPTYPE_IPV4;
+ if(ipv6)
+ bl->iptype |= IPTYPE_IPV6;
+
+ rb_dlinkMoveList(filters, &bl->filters);
+
+ bl->lastwarning = 0;
+
+ return bl;
+}
+
+static struct blacklist *
+find_blacklist(char *name)
+{
+ rb_dlink_node *ptr;
+
+ RB_DLINK_FOREACH(ptr, blacklist_list.head)
+ {
+ struct blacklist *bl = (struct blacklist *)ptr->data;
+
+ if (!strcasecmp(bl->host, name))
+ return bl;
+ }
+
+ return NULL;
+}
+
+static inline bool
+blacklist_check_reply(struct blacklist_lookup *bllookup, const char *ipaddr)
+{
+ struct blacklist *bl = bllookup->bl;
+ const char *lastoctet;
+ rb_dlink_node *ptr;
+
+ /* No filters and entry found - thus positive match */
+ if (!rb_dlink_list_length(&bl->filters))
+ return true;
+
+ /* Below will prolly have to change if IPv6 address replies are sent back */
+ if ((lastoctet = strrchr(ipaddr, '.')) == NULL || *(++lastoctet) == '\0')
+ goto blwarn;
+
+ RB_DLINK_FOREACH(ptr, bl->filters.head)
+ {
+ struct blacklist_filter *filter = ptr->data;
+ const char *cmpstr;
+
+ if (filter->type == FILTER_ALL)
+ cmpstr = ipaddr;
+ else if (filter->type == FILTER_LAST)
+ cmpstr = lastoctet;
+ else
+ {
+ warn_opers(L_CRIT, "BUG: Unknown blacklist filter type on blacklist %s: %d",
+ bl->host, filter->type);
+ continue;
+ }
+
+ if (strcmp(cmpstr, filter->filterstr) == 0)
+ /* Match! */
+ return true;
+ }
+
+ return false;
+blwarn:
+ if (bl->lastwarning + 3600 < rb_current_time())
+ {
+ warn_opers(L_WARN, "Garbage/undecipherable reply received from blacklist %s (reply %s)",
+ bl->host, ipaddr);
+ bl->lastwarning = rb_current_time();
+ }
+ return false;
+}
+
+static void
+blacklist_dns_callback(const char *result, bool status, query_type type, void *data)
+{
+ struct blacklist_lookup *bllookup = (struct blacklist_lookup *)data;
+ struct blacklist_user *bluser;
+ struct auth_client *auth;
+
+ if (bllookup == NULL || bllookup->auth == NULL)
+ return;
+
+ auth = bllookup->auth;
+ bluser = auth->data[PROVIDER_BLACKLIST];
+ if(bluser == NULL)
+ return;
+
+ if (result != NULL && status && blacklist_check_reply(bllookup, result))
+ {
+ /* Match found, so proceed no further */
+ blacklists_cancel(auth);
+ reject_client(auth, PROVIDER_BLACKLIST, bllookup->bl->reason);
+ return;
+ }
+
+ unref_blacklist(bllookup->bl);
+ rb_dlinkDelete(&bllookup->node, &bluser->queries);
+ rb_free(bllookup);
+
+ if(!rb_dlink_list_length(&bluser->queries))
+ {
+ /* Done here */
+ provider_done(auth, PROVIDER_BLACKLIST);
+ rb_free(bluser);
+ auth->data[PROVIDER_BLACKLIST] = NULL;
+ }
+}
+
+static void
+initiate_blacklist_dnsquery(struct blacklist *bl, struct auth_client *auth)
+{
+ struct blacklist_lookup *bllookup = rb_malloc(sizeof(struct blacklist_lookup));
+ struct blacklist_user *bluser = auth->data[PROVIDER_BLACKLIST];
+ char buf[IRCD_RES_HOSTLEN + 1];
+ int aftype;
+
+ bllookup->bl = bl;
+ bllookup->auth = auth;
+
+ aftype = GET_SS_FAMILY(&auth->c_addr);
+ if((aftype == AF_INET && (bl->iptype & IPTYPE_IPV4) == 0) ||
+ (aftype == AF_INET6 && (bl->iptype & IPTYPE_IPV6) == 0))
+ /* Incorrect blacklist type for this IP... */
+ return;
+
+ build_rdns(buf, sizeof(buf), &auth->c_addr, bl->host);
+
+ bllookup->query = lookup_ip(buf, AF_INET, blacklist_dns_callback, bllookup);
+
+ rb_dlinkAdd(bllookup, &bllookup->node, &bluser->queries);
+ bl->refcount++;
+}
+
+/* Timeout outstanding queries */
+static void
+timeout_blacklist_queries_event(void *notused)
+{
+ struct auth_client *auth;
+ rb_dictionary_iter iter;
+
+ RB_DICTIONARY_FOREACH(auth, &iter, auth_clients)
+ {
+ struct blacklist_user *bluser = auth->data[PROVIDER_BLACKLIST];
+
+ if(bluser != NULL && bluser->timeout < rb_current_time())
+ {
+ blacklists_cancel(auth);
+ provider_done(auth, PROVIDER_BLACKLIST);
+ }
+ }
+}
+
+/* public interfaces */
+static bool
+blacklists_start(struct auth_client *auth)
+{
+ struct blacklist_user *bluser;
+ rb_dlink_node *nptr;
+
+ if(auth->data[PROVIDER_BLACKLIST] != NULL)
+ return true;
+
+ if(!rb_dlink_list_length(&blacklist_list))
+ /* Nothing to do... */
+ return true;
+
+ bluser = auth->data[PROVIDER_BLACKLIST] = rb_malloc(sizeof(struct blacklist_user));
+
+ RB_DLINK_FOREACH(nptr, blacklist_list.head)
+ {
+ struct blacklist *bl = (struct blacklist *) nptr->data;
+
+ if (!bl->delete)
+ initiate_blacklist_dnsquery(bl, auth);
+ }
+
+ bluser->timeout = rb_current_time() + blacklist_timeout;
+
+ set_provider(auth, PROVIDER_BLACKLIST);
+ return true;
+}
+
+static void
+blacklists_cancel(struct auth_client *auth)
+{
+ rb_dlink_node *ptr, *nptr;
+ struct blacklist_user *bluser = auth->data[PROVIDER_BLACKLIST];
+
+ if(bluser == NULL)
+ return;
+
+ RB_DLINK_FOREACH_SAFE(ptr, nptr, bluser->queries.head)
+ {
+ struct blacklist_lookup *bllookup = ptr->data;
+ rb_dlinkDelete(&bllookup->node, &bluser->queries);
+ unref_blacklist(bllookup->bl);
+ cancel_query(bllookup->query);
+ rb_free(bllookup);
+ }
+
+ rb_free(bluser);
+ auth->data[PROVIDER_BLACKLIST] = NULL;
+}
+
+static bool
+blacklists_init(void)
+{
+ timeout_ev = rb_event_addish("timeout_blacklist_queries_event", timeout_blacklist_queries_event, NULL, 1);
+ return (timeout_ev != NULL);
+}
+
+static void
+blacklists_destroy(void)
+{
+ rb_dlink_node *ptr, *nptr;
+ rb_dictionary_iter iter;
+ struct blacklist *bl;
+ struct auth_client *auth;
+
+ RB_DICTIONARY_FOREACH(auth, &iter, auth_clients)
+ {
+ blacklists_cancel(auth);
+ }
+
+ RB_DLINK_FOREACH_SAFE(ptr, nptr, blacklist_list.head)
+ {
+ bl = ptr->data;
+ if (bl->refcount > 0)
+ bl->delete = true;
+ else
+ {
+ rb_free(ptr->data);
+ rb_dlinkDestroy(ptr, &blacklist_list);
+ }
+ }
+}
+
+struct auth_provider blacklist_provider =
+{
+ .id = PROVIDER_BLACKLIST,
+ .init = blacklists_init,
+ .destroy = blacklists_destroy,
+ .start = blacklists_start,
+ .cancel = blacklists_cancel,
+ .completed = NULL,
+};
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