src/auth/auth-request-handler.c

	auth-request-handler.c revision 708ea1c397d89586af66c97d74c907f3f2b95134
/* Copyright (c) 2005-2008 Dovecot authors, see the included COPYING file */

#include "common.h"
#include "ioloop.h"
#include "array.h"
#include "aqueue.h"
#include "base64.h"
#include "hash.h"
#include "str.h"
#include "str-sanitize.h"
#include "auth-request.h"
#include "auth-master-connection.h"
#include "auth-request-handler.h"

#include <stdlib.h>

#define DEFAULT_AUTH_FAILURE_DELAY 2
#define AUTH_FAILURE_DELAY_CHECK_MSECS 500

struct auth_request_handler {
    int refcount;
    pool_t pool;
    struct hash_table *requests;

        struct auth *auth;
        unsigned int connect_uid, client_pid;

    auth_request_callback_t *callback;
    void *context;

    auth_request_callback_t *master_callback;
};

static ARRAY_DEFINE(auth_failures_arr, struct auth_request *);
static struct aqueue *auth_failures;
static struct timeout *to_auth_failures;
static unsigned int auth_failure_delay;

static void auth_failure_timeout(void *context);

#undef auth_request_handler_create
struct auth_request_handler *
auth_request_handler_create(struct auth *auth,
                auth_request_callback_t *callback, void *context,
                auth_request_callback_t *master_callback)
{
    struct auth_request_handler *handler;
    pool_t pool;

    pool = pool_alloconly_create("auth request handler", 4096);

    handler = p_new(pool, struct auth_request_handler, 1);
    handler->refcount = 1;
    handler->pool = pool;
    handler->requests = hash_create(default_pool, pool, 0, NULL, NULL);
    handler->auth = auth;
    handler->callback = callback;
    handler->context = context;
    handler->master_callback = master_callback;
    return handler;
}

void auth_request_handler_unref(struct auth_request_handler **_handler)
{
        struct auth_request_handler *handler = *_handler;
    struct hash_iterate_context *iter;
    void *key, *value;

    *_handler = NULL;
    i_assert(handler->refcount > 0);
    if (--handler->refcount > 0)
        return;

    iter = hash_iterate_init(handler->requests);
    while (hash_iterate(iter, &key, &value)) {
        struct auth_request *auth_request = value;

        auth_request_unref(&auth_request);
    }
    hash_iterate_deinit(&iter);

    /* notify parent that we're done with all requests */
    handler->callback(NULL, handler->context);

    hash_destroy(&handler->requests);
    pool_unref(&handler->pool);
}

void auth_request_handler_set(struct auth_request_handler *handler,
                  unsigned int connect_uid,
                  unsigned int client_pid)
{
    handler->connect_uid = connect_uid;
    handler->client_pid = client_pid;
}

static void auth_request_handler_remove(struct auth_request_handler *handler,
                    struct auth_request *request)
{
    hash_remove(handler->requests, POINTER_CAST(request->id));
    auth_request_unref(&request);
}

void auth_request_handler_check_timeouts(struct auth_request_handler *handler)
{
    struct hash_iterate_context *iter;
    void *key, *value;

    iter = hash_iterate_init(handler->requests);
    while (hash_iterate(iter, &key, &value)) {
        struct auth_request *request = value;

        if (request->last_access + AUTH_REQUEST_TIMEOUT < ioloop_time)
            auth_request_handler_remove(handler, request);
    }
    hash_iterate_deinit(&iter);
}

static void get_client_extra_fields(struct auth_request *request,
                    struct auth_stream_reply *reply)
{
    const char **fields, *extra_fields;
    unsigned int src, dest;
    bool seen_pass = FALSE;

    if (auth_stream_is_empty(request->extra_fields))
        return;

    extra_fields = auth_stream_reply_export(request->extra_fields);

    if (!request->proxy) {
        /* we only wish to remove all fields prefixed with "userdb_" */
        if (strstr(extra_fields, "userdb_") == NULL) {
            auth_stream_reply_import(reply, extra_fields);
            return;
        }
    }

    fields = t_strsplit(extra_fields, "\t");
    for (src = dest = 0; fields[src] != NULL; src++) {
        if (strncmp(fields[src], "userdb_", 7) != 0) {
            if (!seen_pass && strncmp(fields[src], "pass=", 5) == 0)
                seen_pass = TRUE;
            auth_stream_reply_import(reply, fields[src]);
        }
    }

    if (request->proxy && !seen_pass && request->mech_password != NULL) {
        /* we're proxying - send back the password that was
           sent by user (not the password in passdb). */
        auth_stream_reply_add(reply, "pass", request->mech_password);
    }
}

static void
auth_request_handle_failure(struct auth_request *request,
                struct auth_stream_reply *reply)
{
        struct auth_request_handler *handler = request->context;

    if (request->delayed_failure) {
        /* we came here from flush_failures() */
        handler->callback(reply, handler->context);
        return;
    }

    /* remove the request from requests-list */
    auth_request_ref(request);
    auth_request_handler_remove(handler, request);

    if (request->no_failure_delay) {
        /* passdb specifically requested not to delay the
           reply. */
        handler->callback(reply, handler->context);
        auth_request_unref(&request);
        return;
    }

    /* failure. don't announce it immediately to avoid
       a) timing attacks, b) flooding */
    request->delayed_failure = TRUE;
    handler->refcount++;

    request->last_access = ioloop_time;
    aqueue_append(auth_failures, &request);
    if (to_auth_failures == NULL) {
        to_auth_failures =
            timeout_add(AUTH_FAILURE_DELAY_CHECK_MSECS,
                    auth_failure_timeout, NULL);
    }
}

static void auth_callback(struct auth_request *request,
              enum auth_client_result result,
              const void *auth_reply, size_t reply_size)
{
        struct auth_request_handler *handler = request->context;
    struct auth_stream_reply *reply;
    string_t *str;

    reply = auth_stream_reply_init(pool_datastack_create());
    switch (result) {
    case AUTH_CLIENT_RESULT_CONTINUE:
        auth_stream_reply_add(reply, "CONT", NULL);
        auth_stream_reply_add(reply, NULL, dec2str(request->id));

        str = t_str_new(MAX_BASE64_ENCODED_SIZE(reply_size));
        base64_encode(auth_reply, reply_size, str);
        auth_stream_reply_add(reply, NULL, str_c(str));

        request->accept_input = TRUE;
        handler->callback(reply, handler->context);
        break;
    case AUTH_CLIENT_RESULT_SUCCESS:
        auth_request_proxy_finish(request, TRUE);

        auth_stream_reply_add(reply, "OK", NULL);
        auth_stream_reply_add(reply, NULL, dec2str(request->id));
        auth_stream_reply_add(reply, "user", request->user);
        if (reply_size > 0) {
            str = t_str_new(MAX_BASE64_ENCODED_SIZE(reply_size));
            base64_encode(auth_reply, reply_size, str);
            auth_stream_reply_add(reply, "resp", str_c(str));
        }
        get_client_extra_fields(request, reply);
        if (request->no_login || handler->master_callback == NULL) {
            /* this request doesn't have to wait for master
               process to pick it up. delete it */
            auth_request_handler_remove(handler, request);
        }
        handler->callback(reply, handler->context);
        break;
    case AUTH_CLIENT_RESULT_FAILURE:
        auth_request_proxy_finish(request, FALSE);

        auth_stream_reply_add(reply, "FAIL", NULL);
        auth_stream_reply_add(reply, NULL, dec2str(request->id));
        if (request->user != NULL)
            auth_stream_reply_add(reply, "user", request->user);

        if (request->internal_failure)
            auth_stream_reply_add(reply, "temp", NULL);
        else if (request->master_user != NULL) {
            /* authentication succeeded, but we can't log in
               as the wanted user */
            auth_stream_reply_add(reply, "authz", NULL);
        }
        get_client_extra_fields(request, reply);

        auth_request_handle_failure(request, reply);
        break;
    }
    /* NOTE: request may be destroyed now */

        auth_request_handler_unref(&handler);
}

static void auth_request_handler_auth_fail(struct auth_request_handler *handler,
                       struct auth_request *request,
                       const char *reason)
{
    struct auth_stream_reply *reply;

    auth_request_log_info(request, request->mech->mech_name, "%s", reason);

    reply = auth_stream_reply_init(pool_datastack_create());
    auth_stream_reply_add(reply, "FAIL", NULL);
    auth_stream_reply_add(reply, NULL, dec2str(request->id));
    auth_stream_reply_add(reply, "reason", reason);

    handler->callback(reply, handler->context);
    auth_request_handler_remove(handler, request);
}

bool auth_request_handler_auth_begin(struct auth_request_handler *handler,
                     const char *args)
{
    const struct mech_module *mech;
    struct auth_request *request;
    const char *const *list, *name, *arg, *initial_resp;
    const void *initial_resp_data;
    size_t initial_resp_len;
    unsigned int id;
    buffer_t *buf;

    /* <id> <mechanism> [...] */
    list = t_strsplit(args, "\t");
    if (list[0] == NULL || list[1] == NULL) {
        i_error("BUG: Authentication client %u "
            "sent broken AUTH request", handler->client_pid);
        return FALSE;
    }

    id = (unsigned int)strtoul(list[0], NULL, 10);

    mech = mech_module_find(list[1]);
    if (mech == NULL) {
        /* unsupported mechanism */
        i_error("BUG: Authentication client %u requested unsupported "
            "authentication mechanism %s", handler->client_pid,
            str_sanitize(list[1], MAX_MECH_NAME_LEN));
        return FALSE;
    }

    request = auth_request_new(handler->auth, mech, auth_callback, handler);
    request->connect_uid = handler->connect_uid;
    request->client_pid = handler->client_pid;
    request->id = id;

    /* parse optional parameters */
    initial_resp = NULL;
    for (list += 2; *list != NULL; list++) {
        arg = strchr(*list, '=');
        if (arg == NULL) {
            name = *list;
            arg = "";
        } else {
            name = t_strdup_until(*list, arg);
            arg++;
        }

        if (auth_request_import(request, name, arg))
            ;
        else if (strcmp(name, "resp") == 0) {
            initial_resp = arg;
            /* this must be the last parameter */
            list++;
            break;
        }
    }

    if (*list != NULL) {
        i_error("BUG: Authentication client %u "
            "sent AUTH parameters after 'resp'",
            handler->client_pid);
        return FALSE;
    }

    if (request->service == NULL) {
        i_error("BUG: Authentication client %u "
            "didn't specify service in request",
            handler->client_pid);
        return FALSE;
    }

    hash_insert(handler->requests, POINTER_CAST(id), request);

    if (request->auth->ssl_require_client_cert &&
        !request->valid_client_cert) {
        /* we fail without valid certificate */
                auth_request_handler_auth_fail(handler, request,
            "Client didn't present valid SSL certificate");
        return TRUE;
    }

    if (initial_resp == NULL) {
        initial_resp_data = NULL;
        initial_resp_len = 0;
    } else {
        size_t len = strlen(initial_resp);
        buf = buffer_create_dynamic(pool_datastack_create(),
                        MAX_BASE64_DECODED_SIZE(len));
        if (base64_decode(initial_resp, len, NULL, buf) < 0) {
                        auth_request_handler_auth_fail(handler, request,
                "Invalid base64 data in initial response");
            return TRUE;
        }
        initial_resp_data = buf->data;
        initial_resp_len = buf->used;
    }

    /* handler is referenced until auth_callback is called. */
    handler->refcount++;
    auth_request_initial(request, initial_resp_data, initial_resp_len);
    return TRUE;
}

bool auth_request_handler_auth_continue(struct auth_request_handler *handler,
                    const char *args)
{
    struct auth_request *request;
    const char *data;
    size_t data_len;
    buffer_t *buf;
    unsigned int id;

    data = strchr(args, '\t');
    if (data == NULL) {
        i_error("BUG: Authentication client sent broken CONT request");
        return FALSE;
    }
    data++;

    id = (unsigned int)strtoul(args, NULL, 10);

    request = hash_lookup(handler->requests, POINTER_CAST(id));
    if (request == NULL) {
        struct auth_stream_reply *reply;

        reply = auth_stream_reply_init(pool_datastack_create());
        auth_stream_reply_add(reply, "FAIL", NULL);
        auth_stream_reply_add(reply, NULL, dec2str(id));
        auth_stream_reply_add(reply, "reason", "Timeouted");
        handler->callback(reply, handler->context);
        return TRUE;
    }

    /* accept input only once after mechanism has sent a CONT reply */
    if (!request->accept_input) {
        auth_request_handler_auth_fail(handler, request,
                           "Unexpected continuation");
        return TRUE;
    }
    request->accept_input = FALSE;

    data_len = strlen(data);
    buf = buffer_create_dynamic(pool_datastack_create(),
                    MAX_BASE64_DECODED_SIZE(data_len));
    if (base64_decode(data, data_len, NULL, buf) < 0) {
        auth_request_handler_auth_fail(handler, request,
            "Invalid base64 data in continued response");
        return TRUE;
    }

    /* handler is referenced until auth_callback is called. */
    handler->refcount++;
    auth_request_continue(request, buf->data, buf->used);
    return TRUE;
}

static void userdb_callback(enum userdb_result result,
                struct auth_request *request)
{
        struct auth_request_handler *handler = request->context;
    struct auth_stream_reply *reply;

    i_assert(request->state == AUTH_REQUEST_STATE_USERDB);

    request->state = AUTH_REQUEST_STATE_FINISHED;

    if (request->userdb_lookup_failed)
        result = USERDB_RESULT_INTERNAL_FAILURE;

    reply = auth_stream_reply_init(pool_datastack_create());
    switch (result) {
    case USERDB_RESULT_INTERNAL_FAILURE:
        auth_stream_reply_add(reply, "FAIL", NULL);
        auth_stream_reply_add(reply, NULL, dec2str(request->id));
        break;
    case USERDB_RESULT_USER_UNKNOWN:
        auth_stream_reply_add(reply, "NOTFOUND", NULL);
        auth_stream_reply_add(reply, NULL, dec2str(request->id));
        break;
    case USERDB_RESULT_OK:
        auth_stream_reply_add(reply, "USER", NULL);
        auth_stream_reply_add(reply, NULL, dec2str(request->id));
        if (request->master_user != NULL) {
            auth_stream_reply_add(request->userdb_reply,
                          "master_user",
                          request->master_user);
        }
        auth_stream_reply_import(reply,
            auth_stream_reply_export(request->userdb_reply));
        break;
    }
    handler->master_callback(reply, request->master);

    auth_master_connection_unref(&request->master);
    auth_request_unref(&request);
        auth_request_handler_unref(&handler);
}

void auth_request_handler_master_request(struct auth_request_handler *handler,
                     struct auth_master_connection *master,
                     unsigned int id,
                     unsigned int client_id)
{
    struct auth_request *request;
    struct auth_stream_reply *reply;

    reply = auth_stream_reply_init(pool_datastack_create());

    request = hash_lookup(handler->requests, POINTER_CAST(client_id));
    if (request == NULL) {
        i_error("Master request %u.%u not found",
            handler->client_pid, client_id);
        auth_stream_reply_add(reply, "NOTFOUND", NULL);
        auth_stream_reply_add(reply, NULL, dec2str(id));
        handler->master_callback(reply, master);
        return;
    }

    auth_request_ref(request);
    auth_request_handler_remove(handler, request);

    if (request->state != AUTH_REQUEST_STATE_FINISHED ||
        !request->successful) {
        i_error("Master requested unfinished authentication request "
            "%u.%u", handler->client_pid, client_id);
        auth_stream_reply_add(reply, "NOTFOUND", NULL);
        auth_stream_reply_add(reply, NULL, dec2str(id));
        handler->master_callback(reply, master);
        auth_request_unref(&request);
    } else {
        /* the request isn't being referenced anywhere anymore,
           so we can do a bit of kludging.. replace the request's
           old client_id with master's id. */
        request->state = AUTH_REQUEST_STATE_USERDB;
        request->id = id;
        request->context = handler;
        request->master = master;

        /* master and handler are referenced until userdb_callback i
           s called. */
        auth_master_connection_ref(master);
        handler->refcount++;
        auth_request_lookup_user(request, userdb_callback);
    }
}

void auth_request_handler_flush_failures(bool flush_all)
{
    struct auth_request **auth_requests, *auth_request;
    unsigned int i, count;
    time_t diff;

    count = aqueue_count(auth_failures);
    if (count == 0) {
        if (to_auth_failures != NULL)
            timeout_remove(&to_auth_failures);
        return;
    }

    auth_requests = array_idx_modifiable(&auth_failures_arr, 0);
    for (i = 0; i < count; i++) {
        auth_request = auth_requests[aqueue_idx(auth_failures, 0)];

        diff = ioloop_time - auth_request->last_access;
        if (diff < (time_t)auth_failure_delay && !flush_all)
            break;

        aqueue_delete_tail(auth_failures);

        i_assert(auth_request->state == AUTH_REQUEST_STATE_FINISHED);
        auth_request->callback(auth_request,
                       AUTH_CLIENT_RESULT_FAILURE, NULL, 0);
        auth_request_unref(&auth_request);
    }
}

static void auth_failure_timeout(void *context ATTR_UNUSED)
{
    auth_request_handler_flush_failures(FALSE);
}

void auth_request_handler_init(void)
{
    const char *env;

    env = getenv("FAILURE_DELAY");
    auth_failure_delay = env != NULL ? atoi(env) :
        DEFAULT_AUTH_FAILURE_DELAY;

    i_array_init(&auth_failures_arr, 128);
    auth_failures = aqueue_init(&auth_failures_arr.arr);
}

void auth_request_handler_deinit(void)
{
    auth_request_handler_flush_failures(TRUE);
    array_free(&auth_failures_arr);
    aqueue_deinit(&auth_failures);

    if (to_auth_failures != NULL)
        timeout_remove(&to_auth_failures);
}