solanum/authd/providers/blacklist.c

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/*
* 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,
};