src/auth/userdb.c

/* Copyright (c) 2002-2018 Dovecot authors, see the included COPYING file */

#include "auth-common.h"
#include "array.h"
#include "ipwd.h"
#include "auth-worker-server.h"
#include "userdb.h"

static ARRAY(struct userdb_module_interface *) userdb_interfaces;
static ARRAY(struct userdb_module *) userdb_modules;

static const struct userdb_module_interface userdb_iface_deinit = {
    .name = "deinit"
};

static struct userdb_module_interface *userdb_interface_find(const char *name)
{
    struct userdb_module_interface *const *ifaces;

    array_foreach(&userdb_interfaces, ifaces) {
        struct userdb_module_interface *iface = *ifaces;

        if (strcmp(iface->name, name) == 0)
            return iface;
    }
    return NULL;
}

void userdb_register_module(struct userdb_module_interface *iface)
{
    struct userdb_module_interface *old_iface;

    old_iface = userdb_interface_find(iface->name);
    if (old_iface != NULL && old_iface->lookup == NULL) {
        /* replacing a "support not compiled in" userdb */
        userdb_unregister_module(old_iface);
    } else if (old_iface != NULL) {
        i_panic("userdb_register_module(%s): Already registered",
            iface->name);
    }
    array_append(&userdb_interfaces, &iface, 1);
}

void userdb_unregister_module(struct userdb_module_interface *iface)
{
    struct userdb_module_interface *const *ifaces;
    unsigned int idx;

    array_foreach(&userdb_interfaces, ifaces) {
        if (*ifaces == iface) {
            idx = array_foreach_idx(&userdb_interfaces, ifaces);
            array_delete(&userdb_interfaces, idx, 1);
            return;
        }
    }
    i_panic("userdb_unregister_module(%s): Not registered", iface->name);
}

uid_t userdb_parse_uid(struct auth_request *request, const char *str)
{
    struct passwd pw;
    uid_t uid;

    if (str == NULL)
        return (uid_t)-1;

    if (str_to_uid(str, &uid) == 0)
        return uid;

    switch (i_getpwnam(str, &pw)) {
    case -1:
        i_error("getpwnam() failed: %m");
        return (uid_t)-1;
    case 0:
        if (request != NULL) {
            auth_request_log_error(request, AUTH_SUBSYS_DB,
                           "Invalid UID value '%s'", str);
        }
        return (uid_t)-1;
    default:
        return pw.pw_uid;
    }
}

gid_t userdb_parse_gid(struct auth_request *request, const char *str)
{
    struct group gr;
    gid_t gid;

    if (str == NULL)
        return (gid_t)-1;

    if (str_to_gid(str, &gid) == 0)
        return gid;

    switch (i_getgrnam(str, &gr)) {
    case -1:
        i_error("getgrnam() failed: %m");
        return (gid_t)-1;
    case 0:
        if (request != NULL) {
            auth_request_log_error(request, AUTH_SUBSYS_DB,
                           "Invalid GID value '%s'", str);
        }
        return (gid_t)-1;
    default:
        return gr.gr_gid;
    }
}

static struct userdb_module *
userdb_find(const char *driver, const char *args, unsigned int *idx_r)
{
    struct userdb_module *const *userdbs;
    unsigned int i, count;

    userdbs = array_get(&userdb_modules, &count);
    for (i = 0; i < count; i++) {
        if (strcmp(userdbs[i]->iface->name, driver) == 0 &&
            strcmp(userdbs[i]->args, args) == 0) {
            *idx_r = i;
            return userdbs[i];
        }
    }
    return NULL;
}

struct userdb_module *
userdb_preinit(pool_t pool, const struct auth_userdb_settings *set)
{
    static unsigned int auth_userdb_id = 0;
    struct userdb_module_interface *iface;
    struct userdb_module *userdb;
    unsigned int idx;

    iface = userdb_interface_find(set->driver);
    if (iface == NULL || iface->lookup == NULL) {
        /* maybe it's a plugin. try to load it. */
        auth_module_load(t_strconcat("authdb_", set->driver, NULL));
        iface = userdb_interface_find(set->driver);
    }
    if (iface == NULL)
        i_fatal("Unknown userdb driver '%s'", set->driver);
    if (iface->lookup == NULL) {
        i_fatal("Support not compiled in for userdb driver '%s'",
            set->driver);
    }
    if (iface->preinit == NULL && iface->init == NULL &&
        *set->args != '\0') {
        i_fatal("userdb %s: No args are supported: %s",
            set->driver, set->args);
    }

    userdb = userdb_find(set->driver, set->args, &idx);
    if (userdb != NULL)
        return userdb;

    if (iface->preinit == NULL)
        userdb = p_new(pool, struct userdb_module, 1);
    else
        userdb = iface->preinit(pool, set->args);
    userdb->id = ++auth_userdb_id;
    userdb->iface = iface;
    userdb->args = p_strdup(pool, set->args);

    array_append(&userdb_modules, &userdb, 1);
    return userdb;
}

void userdb_init(struct userdb_module *userdb)
{
    if (userdb->iface->init != NULL && userdb->init_refcount == 0)
        userdb->iface->init(userdb);
    userdb->init_refcount++;
}

void userdb_deinit(struct userdb_module *userdb)
{
    unsigned int idx;

    i_assert(userdb->init_refcount > 0);

    if (--userdb->init_refcount > 0)
        return;

    if (userdb_find(userdb->iface->name, userdb->args, &idx) == NULL)
        i_unreached();
    array_delete(&userdb_modules, idx, 1);

    if (userdb->iface->deinit != NULL)
        userdb->iface->deinit(userdb);

    /* make sure userdb isn't accessed again */
    userdb->iface = &userdb_iface_deinit;
}

void userdbs_generate_md5(unsigned char md5[STATIC_ARRAY MD5_RESULTLEN])
{
    struct md5_context ctx;
    struct userdb_module *const *userdbs;
    unsigned int i, count;

    md5_init(&ctx);
    userdbs = array_get(&userdb_modules, &count);
    for (i = 0; i < count; i++) {
        md5_update(&ctx, &userdbs[i]->id, sizeof(userdbs[i]->id));
        md5_update(&ctx, userdbs[i]->iface->name,
               strlen(userdbs[i]->iface->name));
        md5_update(&ctx, userdbs[i]->args, strlen(userdbs[i]->args));
    }
    md5_final(&ctx, md5);
}

extern struct userdb_module_interface userdb_prefetch;
extern struct userdb_module_interface userdb_static;
extern struct userdb_module_interface userdb_passwd;
extern struct userdb_module_interface userdb_passwd_file;
extern struct userdb_module_interface userdb_vpopmail;
extern struct userdb_module_interface userdb_ldap;
extern struct userdb_module_interface userdb_sql;
extern struct userdb_module_interface userdb_checkpassword;
extern struct userdb_module_interface userdb_dict;
#ifdef HAVE_LUA
extern struct userdb_module_interface userdb_lua;
#endif

void userdbs_init(void)
{
    i_array_init(&userdb_interfaces, 16);
    i_array_init(&userdb_modules, 16);
    userdb_register_module(&userdb_passwd);
    userdb_register_module(&userdb_passwd_file);
    userdb_register_module(&userdb_prefetch);
    userdb_register_module(&userdb_static);
    userdb_register_module(&userdb_vpopmail);
    userdb_register_module(&userdb_ldap);
    userdb_register_module(&userdb_sql);
    userdb_register_module(&userdb_checkpassword);
    userdb_register_module(&userdb_dict);
#ifdef HAVE_LUA
    userdb_register_module(&userdb_lua);
#endif
}

void userdbs_deinit(void)
{
    array_free(&userdb_modules);
    array_free(&userdb_interfaces);
}