solanum/authd/provider.c

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/* authd/provider.c - authentication provider framework
* Copyright (c) 2016 Elizabeth Myers <elizabeth@interlinked.me>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice is present in all copies.
*
* 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.
*/
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/* The basic design here is to have "authentication providers" that do things
* like query ident and blacklists and even open proxies.
*
* Providers are registered in the auth_providers linked list. It is planned to
* use a bitmap to store provider ID's later.
*
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* Providers can either return failure immediately, immediate acceptance, or do
* work in the background (calling set_provider to signal this).
*
* Provider-specific data for each client can be kept in an index of the data
* struct member (using the provider's ID).
*
* All providers must implement at a minimum a perform_provider function. You
* don't have to implement the others if you don't need them.
*
* Providers may kick clients off by rejecting them. Upon rejection, all
* providers are cancelled. They can also unconditionally accept them.
*
* When a provider is done and is neutral on accepting/rejecting a client, it
* should call provider_done. Do NOT call this if you have accepted or rejected
* the client.
*
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* Eventually, stuff like *:line handling will be moved here, but that means we
* have to talk to bandb directly first.
*
* --Elizafox, 9 March 2016
*/
#include "stdinc.h"
#include "rb_dictionary.h"
#include "rb_lib.h"
#include "authd.h"
#include "provider.h"
#include "notice.h"
static EVH provider_timeout_event;
rb_dictionary *auth_clients;
rb_dlink_list auth_providers;
static rb_dlink_list free_pids;
static uint32_t allocated_pids;
static struct ev_entry *timeout_ev;
/* Set a provider's raw status */
static inline void
set_provider_status(struct auth_client *auth, uint32_t provider, provider_status_t status)
{
auth->data[provider].status = status;
}
/* Set the provider as running */
static inline void
set_provider_running(struct auth_client *auth, uint32_t provider)
{
auth->providers_active++;
set_provider_status(auth, provider, PROVIDER_STATUS_RUNNING);
}
/* Provider is no longer operating on this auth client */
static inline void
set_provider_done(struct auth_client *auth, uint32_t provider)
{
set_provider_status(auth, provider, PROVIDER_STATUS_DONE);
auth->providers_active--;
}
/* Initalise all providers */
void
init_providers(void)
{
auth_clients = rb_dictionary_create("pending auth clients", rb_uint32cmp);
timeout_ev = rb_event_addish("provider_timeout_event", provider_timeout_event, NULL, 1);
/* FIXME must be started before rdns/ident to receive completion notification from them */
load_provider(&blacklist_provider);
load_provider(&opm_provider);
/* FIXME must be started after blacklist/opm in case of early completion notifications */
load_provider(&rdns_provider);
load_provider(&ident_provider);
}
/* Terminate all providers */
void
destroy_providers(void)
{
rb_dlink_node *ptr, *nptr;
rb_dictionary_iter iter;
struct auth_client *auth;
/* Cancel outstanding connections */
RB_DICTIONARY_FOREACH(auth, &iter, auth_clients)
{
auth_client_ref(auth);
/* TBD - is this the right thing? */
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reject_client(auth, UINT32_MAX, "destroy",
"Authentication system is down... try reconnecting in a few seconds");
auth_client_unref(auth);
}
RB_DLINK_FOREACH_SAFE(ptr, nptr, auth_providers.head)
{
struct auth_provider *provider = ptr->data;
if(provider->destroy)
provider->destroy();
rb_dlinkDelete(ptr, &auth_providers);
}
rb_dictionary_destroy(auth_clients, NULL, NULL);
rb_event_delete(timeout_ev);
}
/* Load a provider */
void
load_provider(struct auth_provider *provider)
{
/* Assign a PID */
if(rb_dlink_list_length(&free_pids) > 0)
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{
/* use the free list */
provider->id = RB_POINTER_TO_UINT(free_pids.head->data);
rb_dlinkDestroy(free_pids.head, &free_pids);
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}
else
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{
if(allocated_pids == MAX_PROVIDERS || allocated_pids == UINT32_MAX)
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{
warn_opers(L_WARN, "Cannot load additional provider, max reached!");
return;
}
provider->id = allocated_pids++;
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}
if(provider->opt_handlers != NULL)
{
struct auth_opts_handler *handler;
for(handler = provider->opt_handlers; handler->option != NULL; handler++)
rb_dictionary_add(authd_option_handlers, handler->option, handler);
}
if(provider->stats_handler.letter != '\0')
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authd_stat_handlers[(unsigned char)provider->stats_handler.letter] = provider->stats_handler.handler;
if(provider->init != NULL)
provider->init();
rb_dlinkAdd(provider, &provider->node, &auth_providers);
}
void
unload_provider(struct auth_provider *provider)
{
if(provider->opt_handlers != NULL)
{
struct auth_opts_handler *handler;
for(handler = provider->opt_handlers; handler->option != NULL; handler++)
rb_dictionary_delete(authd_option_handlers, handler->option);
}
if(provider->stats_handler.letter != '\0')
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authd_stat_handlers[(unsigned char)provider->stats_handler.letter] = NULL;
if(provider->destroy != NULL)
provider->destroy();
rb_dlinkDelete(&provider->node, &auth_providers);
/* Reclaim ID */
rb_dlinkAddAlloc(RB_UINT_TO_POINTER(provider->id), &free_pids);
}
void
auth_client_free(struct auth_client *auth)
{
rb_dictionary_delete(auth_clients, RB_UINT_TO_POINTER(auth->cid));
rb_free(auth->data);
rb_free(auth);
}
/* Cancel outstanding providers for a client (if any). */
void
cancel_providers(struct auth_client *auth)
{
if(auth->providers_cancelled)
return;
auth->providers_cancelled = true;
if(auth->providers_active > 0)
{
rb_dlink_node *ptr;
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RB_DLINK_FOREACH(ptr, auth_providers.head)
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{
struct auth_provider *provider = ptr->data;
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if(provider->cancel != NULL && is_provider_running(auth, provider->id))
/* Cancel if required */
provider->cancel(auth);
}
}
}
/* Provider is done */
void
provider_done(struct auth_client *auth, uint32_t id)
{
rb_dlink_node *ptr;
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lrb_assert(is_provider_running(auth, id));
lrb_assert(id != UINT32_MAX);
lrb_assert(id < allocated_pids);
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set_provider_done(auth, id);
if(auth->providers_active == 0 && !auth->providers_starting)
{
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/* All done */
accept_client(auth);
return;
}
RB_DLINK_FOREACH(ptr, auth_providers.head)
{
struct auth_provider *provider = ptr->data;
if(provider->completed != NULL && is_provider_running(auth, provider->id))
/* Notify pending clients who asked for it */
provider->completed(auth, id);
}
}
/* Reject a client and cancel any outstanding providers */
void
reject_client(struct auth_client *auth, uint32_t id, const char *data, const char *fmt, ...)
{
char buf[BUFSIZE];
va_list args;
va_start(args, fmt);
vsnprintf(buf, sizeof(buf), fmt, args);
va_end(args);
/* We send back username and hostname in case ircd wants to overrule our decision.
* In the future this may not be the case.
* --Elizafox
*/
rb_helper_write(authd_helper, "R %x %c %s %s %s :%s",
auth->cid, id != UINT32_MAX ? auth->data[id].provider->letter : '*',
auth->username, auth->hostname,
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data == NULL ? "*" : data, buf);
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if(id != UINT32_MAX)
set_provider_done(auth, id);
cancel_providers(auth);
}
/* Accept a client and cancel outstanding providers if any */
void
accept_client(struct auth_client *auth)
{
rb_helper_write(authd_helper, "A %x %s %s", auth->cid, auth->username, auth->hostname);
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cancel_providers(auth);
}
/* Begin authenticating user */
static void
start_auth(const char *cid, const char *l_ip, const char *l_port, const char *c_ip, const char *c_port)
{
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struct auth_client *auth;
unsigned long long lcid = strtoull(cid, NULL, 16);
rb_dlink_node *ptr;
if(lcid == 0 || lcid > UINT32_MAX)
return;
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auth = rb_malloc(sizeof(struct auth_client));
auth_client_ref(auth);
auth->cid = (uint32_t)lcid;
if(rb_dictionary_find(auth_clients, RB_UINT_TO_POINTER(auth->cid)) == NULL)
rb_dictionary_add(auth_clients, RB_UINT_TO_POINTER(auth->cid), auth);
else
{
warn_opers(L_CRIT, "provider: duplicate client added via start_auth: %s", cid);
exit(EX_PROVIDER_ERROR);
}
rb_strlcpy(auth->l_ip, l_ip, sizeof(auth->l_ip));
auth->l_port = (uint16_t)atoi(l_port); /* should be safe */
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(void) rb_inet_pton_sock(l_ip, (struct sockaddr *)&auth->l_addr);
SET_SS_PORT(&auth->l_addr, htons(auth->l_port));
rb_strlcpy(auth->c_ip, c_ip, sizeof(auth->c_ip));
auth->c_port = (uint16_t)atoi(c_port);
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(void) rb_inet_pton_sock(c_ip, (struct sockaddr *)&auth->c_addr);
SET_SS_PORT(&auth->c_addr, htons(auth->c_port));
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rb_strlcpy(auth->hostname, "*", sizeof(auth->hostname));
rb_strlcpy(auth->username, "*", sizeof(auth->username));
auth->data = rb_malloc(allocated_pids * sizeof(struct auth_client_data));
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auth->providers_starting = true;
RB_DLINK_FOREACH(ptr, auth_providers.head)
{
struct auth_provider *provider = ptr->data;
auth->data[provider->id].provider = provider;
lrb_assert(provider->start != NULL);
/* Execute providers */
set_provider_running(auth, provider->id);
if(!provider->start(auth))
/* Rejected immediately */
goto done;
if(auth->providers_cancelled)
break;
}
auth->providers_starting = false;
/* If no providers are running, accept the client */
if(auth->providers_active == 0)
accept_client(auth);
done:
auth_client_unref(auth);
}
/* Callback for the initiation */
void
handle_new_connection(int parc, char *parv[])
{
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if(parc < 6)
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{
warn_opers(L_CRIT, "provider: received too few params for new connection (6 expected, got %d)", parc);
exit(EX_PROVIDER_ERROR);
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}
start_auth(parv[1], parv[2], parv[3], parv[4], parv[5]);
}
void
handle_cancel_connection(int parc, char *parv[])
{
struct auth_client *auth;
unsigned long long lcid;
if(parc < 2)
{
warn_opers(L_CRIT, "provider: received too few params for new connection (2 expected, got %d)", parc);
exit(EX_PROVIDER_ERROR);
}
lcid = strtoull(parv[1], NULL, 16);
if(lcid == 0 || lcid > UINT32_MAX)
{
warn_opers(L_CRIT, "provider: got a request to cancel a connection that can't exist: %s", parv[1]);
exit(EX_PROVIDER_ERROR);
}
if((auth = rb_dictionary_retrieve(auth_clients, RB_UINT_TO_POINTER((uint32_t)lcid))) == NULL)
{
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/* This could happen as a race if we've accepted/rejected but they cancel, so don't die here.
* --Elizafox */
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return;
}
auth_client_ref(auth);
cancel_providers(auth);
auth_client_unref(auth);
}
static void
provider_timeout_event(void *notused __unused)
{
struct auth_client *auth;
rb_dictionary_iter iter;
const time_t curtime = rb_current_time();
RB_DICTIONARY_FOREACH(auth, &iter, auth_clients)
{
rb_dlink_node *ptr;
auth_client_ref(auth);
RB_DLINK_FOREACH(ptr, auth_providers.head)
{
struct auth_provider *provider = ptr->data;
const time_t timeout = get_provider_timeout(auth, provider->id);
if(is_provider_running(auth, provider->id) && provider->timeout != NULL &&
timeout > 0 && timeout < curtime)
{
provider->timeout(auth);
}
}
auth_client_unref(auth);
}
}