src/auth/passdb-ldap.c

	passdb-ldap.c revision ac75cf9b005f0fc574e49cd64b71db9bf5efbee2
/* Copyright (c) 2003-2007 Dovecot authors, see the included COPYING file */

#include "common.h"

#ifdef PASSDB_LDAP

#include "hash.h"
#include "str.h"
#include "var-expand.h"
#include "password-scheme.h"
#include "auth-cache.h"
#include "db-ldap.h"
#include "passdb.h"

#include <ldap.h>
#include <stdlib.h>

struct ldap_passdb_module {
    struct passdb_module module;

    struct ldap_connection *conn;
};

struct passdb_ldap_request {
    struct ldap_request request;

    union {
        verify_plain_callback_t *verify_plain;
                lookup_credentials_callback_t *lookup_credentials;
    } callback;
};

static LDAPMessage *
handle_request_get_entry(struct ldap_connection *conn,
             struct auth_request *auth_request,
             struct passdb_ldap_request *request, LDAPMessage *res)
{
    enum passdb_result passdb_result;
    LDAPMessage *entry;
    int ret;

    passdb_result = PASSDB_RESULT_INTERNAL_FAILURE;

    if (res != NULL) {
        /* LDAP query returned something */
        ret = ldap_result2error(conn->ld, res, 0);
        if (ret != LDAP_SUCCESS) {
            auth_request_log_error(auth_request, "ldap",
                           "ldap_search(%s) failed: %s",
                           request->request.filter,
                           ldap_err2string(ret));
        } else {
            /* get the reply */
            entry = ldap_first_entry(conn->ld, res);
            if (entry != NULL) {
                /* success */
                return entry;
            }

            /* no entries returned */
            auth_request_log_info(auth_request, "ldap",
                          "unknown user");
            passdb_result = PASSDB_RESULT_USER_UNKNOWN;
        }
    }

    if (auth_request->credentials_scheme != NULL) {
        request->callback.lookup_credentials(passdb_result, NULL, 0,
                             auth_request);
    } else {
        request->callback.verify_plain(passdb_result, auth_request);
    }
    auth_request_unref(&auth_request);
    return NULL;
}

static void
ldap_query_save_result(struct ldap_connection *conn,
               LDAPMessage *entry, struct auth_request *auth_request)
{
    struct db_ldap_result_iterate_context *ldap_iter;
    const char *name, *value;

    ldap_iter = db_ldap_result_iterate_init(conn, entry, auth_request,
                        conn->pass_attr_map);
    while (db_ldap_result_iterate_next(ldap_iter, &name, &value)) {
        auth_request_set_field(auth_request, name, value,
                       conn->set.default_pass_scheme);
    }
}

static void handle_request(struct ldap_connection *conn,
               struct ldap_request *request, LDAPMessage *res)
{
    struct passdb_ldap_request *ldap_request =
        (struct passdb_ldap_request *)request;
        struct auth_request *auth_request = request->context;
    enum passdb_result passdb_result;
    LDAPMessage *entry;
    const char *password, *scheme;
    int ret;

    entry = handle_request_get_entry(conn, auth_request, ldap_request, res);
    if (entry == NULL)
        return;

    /* got first LDAP entry */
    passdb_result = PASSDB_RESULT_INTERNAL_FAILURE;
    password = NULL;

    ldap_query_save_result(conn, entry, auth_request);
    if (auth_request->passdb_password == NULL) {
        auth_request_log_error(auth_request, "ldap",
                       "No password in reply");
    } else if (ldap_next_entry(conn->ld, entry) != NULL) {
        auth_request_log_error(auth_request, "ldap",
            "pass_filter matched multiple objects, aborting");
    } else if (auth_request->passdb_password == NULL &&
           !auth_request->no_password) {
        auth_request_log_info(auth_request, "ldap",
            "Empty password returned without no_password");
        passdb_result = PASSDB_RESULT_PASSWORD_MISMATCH;
    } else {
        /* passdb_password may change on the way,
           so we'll need to strdup. */
        password = t_strdup(auth_request->passdb_password);
        passdb_result = PASSDB_RESULT_OK;
    }

    scheme = password_get_scheme(&password);
    /* auth_request_set_field() sets scheme */
    i_assert(password == NULL || scheme != NULL);

    /* LDAP's RFC2307 specifies the MD5 scheme for what we call PLAIN-MD5.
       We can detect this case, because base64 doesn't use '$'. */
    if (scheme != NULL && strncasecmp(scheme, "MD5", 3) == 0 &&
        strncmp(password, "$1$", 3) != 0) {
        auth_request_log_debug(auth_request, "ldap",
                       "Password doesn't look like MD5-CRYPT, "
                       "scheme changed to PLAIN-MD5");
        scheme = "PLAIN-MD5";
    }

    if (auth_request->credentials_scheme != NULL) {
        passdb_handle_credentials(passdb_result, password, scheme,
            ldap_request->callback.lookup_credentials,
            auth_request);
    } else {
        if (password != NULL) {
            ret = auth_request_password_verify(auth_request,
                    auth_request->mech_password,
                    password, scheme, "ldap");
            passdb_result = ret > 0 ? PASSDB_RESULT_OK :
                PASSDB_RESULT_PASSWORD_MISMATCH;
        }

        ldap_request->callback.verify_plain(passdb_result,
                            auth_request);
    }
    auth_request_unref(&auth_request);
}

static void authbind_start(struct ldap_connection *conn,
               struct ldap_request *ldap_request)
{
    struct passdb_ldap_request *passdb_ldap_request =
        (struct passdb_ldap_request *)ldap_request;
    struct auth_request *auth_request = ldap_request->context;
    int msgid;

    i_assert(ldap_request->base != NULL);

    if (*auth_request->mech_password == '\0') {
        /* Assume that empty password fails. This is especially
           important with Windows 2003 AD, which always returns success
           with empty passwords. */
        auth_request_log_info(auth_request, "ldap",
                      "Login attempt with empty password");
        passdb_ldap_request->callback.
            verify_plain(PASSDB_RESULT_PASSWORD_MISMATCH,
                     auth_request);
        return;
    }

    if (conn->connected && hash_count(conn->requests) == 0) {
        /* switch back to the default dn before doing the next search
           request */
        conn->last_auth_bind = TRUE;
        i_assert(!conn->binding);

        /* the DN is kept in base variable, a bit ugly.. */
        msgid = ldap_bind(conn->ld, ldap_request->base,
                  auth_request->mech_password,
                  LDAP_AUTH_SIMPLE);
        if (msgid == -1) {
            auth_request_log_error(auth_request, "ldap",
                "ldap_bind(%s) failed: %s",
                ldap_request->base, ldap_get_error(conn));
            passdb_ldap_request->callback.
                verify_plain(PASSDB_RESULT_INTERNAL_FAILURE,
                         auth_request);
            return;
        }

        conn->binding = TRUE;
        hash_insert(conn->requests, POINTER_CAST(msgid), ldap_request);

        auth_request_log_debug(auth_request, "ldap", "bind: dn=%s",
                       ldap_request->base);
    } else {
        db_ldap_add_delayed_request(conn, ldap_request);
    }

    /* Bind started */
    auth_request_ref(auth_request);
}

static void
handle_request_authbind(struct ldap_connection *conn,
            struct ldap_request *ldap_request, LDAPMessage *res)
{
    struct passdb_ldap_request *passdb_ldap_request =
        (struct passdb_ldap_request *)ldap_request;
    struct auth_request *auth_request = ldap_request->context;
    enum passdb_result passdb_result;
    int ret;

    conn->binding = FALSE;
    passdb_result = PASSDB_RESULT_INTERNAL_FAILURE;

    if (res != NULL) {
        ret = ldap_result2error(conn->ld, res, 0);
        if (ret == LDAP_SUCCESS)
            passdb_result = PASSDB_RESULT_OK;
        else if (ret == LDAP_INVALID_CREDENTIALS) {
            auth_request_log_info(auth_request, "ldap",
                          "invalid credentials");
            passdb_result = PASSDB_RESULT_PASSWORD_MISMATCH;
        } else {
            auth_request_log_error(auth_request, "ldap",
                           "ldap_bind() failed: %s",
                           ldap_err2string(ret));
        }
    }

    if (conn->retrying && res == NULL) {
        /* reconnected, retry binding */
        authbind_start(conn, ldap_request);
    } else {
        passdb_ldap_request->callback.
            verify_plain(passdb_result, auth_request);
    }
        auth_request_unref(&auth_request);
}

static void
handle_request_authbind_search(struct ldap_connection *conn,
                   struct ldap_request *ldap_request,
                   LDAPMessage *res)
{
    struct passdb_ldap_request *passdb_ldap_request =
        (struct passdb_ldap_request *)ldap_request;
    struct auth_request *auth_request = ldap_request->context;
    LDAPMessage *entry;
    char *dn;

    entry = handle_request_get_entry(conn, auth_request,
                     passdb_ldap_request, res);
    if (entry == NULL)
        return;

    ldap_query_save_result(conn, entry, auth_request);

    /* switch the handler to the authenticated bind handler */
    dn = ldap_get_dn(conn->ld, entry);
    ldap_request->base = p_strdup(auth_request->pool, dn);
    ldap_memfree(dn);

    ldap_request->filter = NULL;
    ldap_request->callback = handle_request_authbind;

        authbind_start(conn, ldap_request);
    auth_request_unref(&auth_request);
}

static void ldap_lookup_pass(struct auth_request *auth_request,
                 struct ldap_request *ldap_request)
{
    struct passdb_module *_module = auth_request->passdb->passdb;
    struct ldap_passdb_module *module =
        (struct ldap_passdb_module *)_module;
    struct ldap_connection *conn = module->conn;
        const struct var_expand_table *vars;
    const char **attr_names = (const char **)conn->pass_attr_names;
    string_t *str;

    vars = auth_request_get_var_expand_table(auth_request, ldap_escape);

    str = t_str_new(512);
    var_expand(str, conn->set.base, vars);
    ldap_request->base = p_strdup(auth_request->pool, str_c(str));

    str_truncate(str, 0);
    var_expand(str, conn->set.pass_filter, vars);
    ldap_request->filter = p_strdup(auth_request->pool, str_c(str));

    auth_request_ref(auth_request);
    ldap_request->callback = handle_request;
    ldap_request->context = auth_request;
    ldap_request->attributes = conn->pass_attr_names;

    auth_request_log_debug(auth_request, "ldap", "pass search: "
                   "base=%s scope=%s filter=%s fields=%s",
                   ldap_request->base, conn->set.scope,
                   ldap_request->filter,
                   attr_names == NULL ? "(all)" :
                   t_strarray_join(attr_names, ","));

    db_ldap_search(conn, ldap_request, conn->set.ldap_scope);
}

static void
ldap_verify_plain_auth_bind_userdn(struct auth_request *auth_request,
                   struct ldap_request *ldap_request)
{
    struct passdb_module *_module = auth_request->passdb->passdb;
    struct ldap_passdb_module *module =
        (struct ldap_passdb_module *)_module;
    struct ldap_connection *conn = module->conn;
        const struct var_expand_table *vars;
    string_t *dn;

    vars = auth_request_get_var_expand_table(auth_request, ldap_escape);
    dn = t_str_new(512);
    var_expand(dn, conn->set.auth_bind_userdn, vars);

    ldap_request->callback = handle_request_authbind;
    ldap_request->context = auth_request;

    ldap_request->base = p_strdup(auth_request->pool, str_c(dn));
        authbind_start(conn, ldap_request);
}

static void
ldap_verify_plain_authbind(struct auth_request *auth_request,
               struct ldap_request *ldap_request)
{
    struct passdb_module *_module = auth_request->passdb->passdb;
    struct ldap_passdb_module *module =
        (struct ldap_passdb_module *)_module;
    struct ldap_connection *conn = module->conn;
    const struct var_expand_table *vars;
    string_t *str;

    vars = auth_request_get_var_expand_table(auth_request, ldap_escape);

    str = t_str_new(512);
    var_expand(str, conn->set.base, vars);
    ldap_request->base = p_strdup(auth_request->pool, str_c(str));

    str_truncate(str, 0);
    var_expand(str, conn->set.pass_filter, vars);
    ldap_request->filter = p_strdup(auth_request->pool, str_c(str));

    /* we don't need the attributes to perform authentication, but they
       may contain some extra parameters. if a password is returned,
       it's just ignored. */
    ldap_request->attributes = conn->pass_attr_names;

    auth_request_ref(auth_request);
    ldap_request->context = auth_request;
    ldap_request->callback = handle_request_authbind_search;

    auth_request_log_debug(auth_request, "ldap",
                   "bind search: base=%s filter=%s",
                   ldap_request->base, ldap_request->filter);

        db_ldap_search(conn, ldap_request, LDAP_SCOPE_SUBTREE);
}

static void
ldap_verify_plain(struct auth_request *request,
          const char *password ATTR_UNUSED,
          verify_plain_callback_t *callback)
{
    struct passdb_module *_module = request->passdb->passdb;
    struct ldap_passdb_module *module =
        (struct ldap_passdb_module *)_module;
    struct ldap_connection *conn = module->conn;
    struct passdb_ldap_request *ldap_request;

    /* reconnect if needed. this is also done by db_ldap_search(), but
       with auth binds we'll have to do it ourself */
    if (db_ldap_connect(conn)< 0) {
        callback(PASSDB_RESULT_INTERNAL_FAILURE, request);
        return;
    }

    ldap_request = p_new(request->pool, struct passdb_ldap_request, 1);
    ldap_request->callback.verify_plain = callback;

    if (!conn->set.auth_bind)
        ldap_lookup_pass(request, &ldap_request->request);
    else if (conn->set.auth_bind_userdn == NULL)
        ldap_verify_plain_authbind(request, &ldap_request->request);
    else
        ldap_verify_plain_auth_bind_userdn(request, &ldap_request->request);
}

static void ldap_lookup_credentials(struct auth_request *request,
                    lookup_credentials_callback_t *callback)
{
    struct passdb_ldap_request *ldap_request;

    ldap_request = p_new(request->pool, struct passdb_ldap_request, 1);
    ldap_request->callback.lookup_credentials = callback;

        ldap_lookup_pass(request, &ldap_request->request);
}

static struct passdb_module *
passdb_ldap_preinit(struct auth_passdb *auth_passdb, const char *args)
{
    struct ldap_passdb_module *module;
    struct ldap_connection *conn;

    module = p_new(auth_passdb->auth->pool, struct ldap_passdb_module, 1);
    module->conn = conn = db_ldap_init(args);
    conn->pass_attr_map =
        hash_create(default_pool, conn->pool, 0, str_hash,
                (hash_cmp_callback_t *)strcmp);

    db_ldap_set_attrs(conn, conn->set.pass_attrs, &conn->pass_attr_names,
              conn->pass_attr_map,
              conn->set.auth_bind ? "password" : NULL);
    module->module.cache_key =
        auth_cache_parse_key(auth_passdb->auth->pool,
                     t_strconcat(conn->set.base,
                         conn->set.pass_filter, NULL));
    module->module.default_pass_scheme = conn->set.default_pass_scheme;
    return &module->module;
}

static void passdb_ldap_init(struct passdb_module *_module,
                 const char *args ATTR_UNUSED)
{
    struct ldap_passdb_module *module =
        (struct ldap_passdb_module *)_module;

    (void)db_ldap_connect(module->conn);

    if (module->conn->set.auth_bind) {
        /* Credential lookups can't be done with authentication binds */
        _module->iface.lookup_credentials = NULL;
    }
}

static void passdb_ldap_deinit(struct passdb_module *_module)
{
    struct ldap_passdb_module *module =
        (struct ldap_passdb_module *)_module;

    db_ldap_unref(&module->conn);
}

struct passdb_module_interface passdb_ldap = {
    "ldap",

    passdb_ldap_preinit,
    passdb_ldap_init,
    passdb_ldap_deinit,

    ldap_verify_plain,
    ldap_lookup_credentials,
    NULL
};

#endif