src/util/script-login.c

	script-login.c revision 3c296d819c54e21ce05c3d2eeeedc79be42ac593
/* Copyright (c) 2009-2012 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "env-util.h"
#include "execv-const.h"
#include "fdpass.h"
#include "restrict-access.h"
#include "str.h"
#include "strescape.h"
#include "settings-parser.h"
#include "mail-storage-service.h"
#include "master-interface.h"
#include "master-service.h"
#include "master-service-settings.h"

#include <stdlib.h>
#include <unistd.h>

#define SCRIPT_LOGIN_PROTOCOL_VERSION_MAJOR 1
#define SCRIPT_LOGIN_READ_TIMEOUT_SECS 10
#define ENV_USERDB_KEYS "USERDB_KEYS"
#define SCRIPT_COMM_FD 3

static const char **exec_args;
static bool drop_to_userdb_privileges = FALSE;

static void client_connected(struct master_service_connection *conn)
{
    enum mail_storage_service_flags flags =
        MAIL_STORAGE_SERVICE_FLAG_NO_PLUGINS;
    string_t *instr, *keys;
    const char **args, *key, *value, *error, *version_line, *data_line;
    struct mail_storage_service_ctx *service_ctx;
    struct mail_storage_service_input input;
    struct mail_storage_service_user *user;
    char buf[1024];
    unsigned int i, socket_count;
    int fd = -1;
    ssize_t ret;

    alarm(SCRIPT_LOGIN_READ_TIMEOUT_SECS);

    net_set_nonblock(conn->fd, FALSE);
    instr = t_str_new(1024);
    ret = fd_read(conn->fd, buf, sizeof(buf), &fd);
    while (ret > 0) {
        str_append_n(instr, buf, ret);
        if (buf[ret-1] == '\n' &&
            strchr(str_c(instr), '\n')[1] != '\0') {
            str_truncate(instr, str_len(instr)-1);
            break;
        }

        ret = read(conn->fd, buf, sizeof(buf));
    }

    version_line = str_c(instr);
    data_line = strchr(version_line, '\n');
    if (data_line != NULL)
        version_line = t_strdup_until(version_line, data_line++);
    else
        version_line = NULL;

    if (ret > 0 || version_line != NULL) {
        if (version_line == NULL ||
            !version_string_verify(version_line, "script-login",
                SCRIPT_LOGIN_PROTOCOL_VERSION_MAJOR)) {
            i_fatal("Client not compatible with this binary "
                "(connecting to wrong socket?)");
        }
    }

    if (ret <= 0) {
        if (ret < 0)
            i_fatal("read() failed: %m");
        else
            i_fatal("read() failed: disconnected");
    }
    if (fd == -1)
        i_fatal("client fd not received");

    alarm(0);

    /* put everything to environment */
    env_clean();
    keys = t_str_new(256);
    args = t_strsplit_tab(data_line);

    if (str_array_length(args) < 3)
        i_fatal("Missing input fields");

    i = 0;
    memset(&input, 0, sizeof(input));
    input.module = "mail"; /* need to get mail_uid, mail_gid */
    input.service = "script-login";
    (void)net_addr2ip(args[i++], &input.local_ip);
    (void)net_addr2ip(args[i++], &input.remote_ip);
    input.username = args[i++];
    input.userdb_fields = args + i;

    env_put(t_strconcat("LOCAL_IP=", net_ip2addr(&input.local_ip), NULL));
    env_put(t_strconcat("IP=", net_ip2addr(&input.remote_ip), NULL));
    env_put(t_strconcat("USER=", input.username, NULL));

    for (; args[i] != '\0'; i++) {
        args[i] = str_tabunescape(t_strdup_noconst(args[i]));
        value = strchr(args[i], '=');
        if (value != NULL) {
            key = t_str_ucase(t_strdup_until(args[i], value));
            env_put(t_strconcat(key, value, NULL));
            str_printfa(keys, "%s ", key);
        }
    }
    env_put(t_strconcat(ENV_USERDB_KEYS"=", str_c(keys), NULL));

    master_service_init_log(master_service,
        t_strdup_printf("script-login(%s): ", input.username));

    if (drop_to_userdb_privileges) {
        service_ctx = mail_storage_service_init(master_service, NULL, flags);
        if (mail_storage_service_lookup(service_ctx, &input, &user, &error) <= 0)
            i_fatal("%s", error);
        mail_storage_service_restrict_setenv(service_ctx, user);
        /* we can't exec anything in a chroot */
        env_remove("RESTRICT_CHROOT");
        restrict_access_by_env(getenv("HOME"), TRUE);
    }

    if (dup2(fd, STDIN_FILENO) < 0)
        i_fatal("dup2() failed: %m");
    if (dup2(fd, STDOUT_FILENO) < 0)
        i_fatal("dup2() failed: %m");
    if (close(fd) < 0)
        i_fatal("close() failed: %m");
    if (conn->fd != SCRIPT_COMM_FD) {
        if (dup2(conn->fd, SCRIPT_COMM_FD) < 0)
            i_fatal("dup2() failed: %m");
        if (close(conn->fd) < 0)
            i_fatal("close() failed: %m");
    }

    /* close all listener sockets */
    socket_count = master_service_get_socket_count(master_service);
    for (i = 0; i < socket_count; i++) {
        if (close(MASTER_LISTEN_FD_FIRST + i) < 0)
            i_error("close(listener) failed: %m");
    }
    if (close(MASTER_STATUS_FD) < 0)
        i_error("close(status) failed: %m");

    execvp_const(exec_args[0], exec_args);
}

static void script_execute_finish(void)
{
    const char *keys_str, *username, *const *keys, *value;
    string_t *reply = t_str_new(512);
    ssize_t ret;

    keys_str = getenv(ENV_USERDB_KEYS);
    if (keys_str == NULL)
        i_fatal(ENV_USERDB_KEYS" environment missing");

    username = getenv("USER");
    if (username == NULL)
        i_fatal("USER environment missing");
    str_append(reply, username);

    for (keys = t_strsplit_spaces(keys_str, " "); *keys != NULL; keys++) {
        value = getenv(t_str_ucase(*keys));
        if (value != NULL) {
            str_append_c(reply, '\t');
            str_tabescape_write(reply,
                        t_strconcat(t_str_lcase(*keys), "=",
                            value, NULL));
        }
    }
    str_append_c(reply, '\n');

    /* finish by sending the fd to the mail process */
    ret = fd_send(SCRIPT_COMM_FD, STDOUT_FILENO,
              str_data(reply), str_len(reply));
    if (ret == (ssize_t)str_len(reply)) {
        /* success */
    } else {
        if (ret < 0)
            i_error("fd_send() failed: %m");
        else
            i_error("fd_send() sent partial output");
        /* exit with 0 even though we failed. non-0 exit just makes
           master log an unnecessary error. */
    }
}

int main(int argc, char *argv[])
{
    enum master_service_flags flags = 0;
    int i, c;

    if (getenv(MASTER_IS_PARENT_ENV) == NULL)
        flags |= MASTER_SERVICE_FLAG_STANDALONE;

    master_service = master_service_init("script-login", flags,
                         &argc, &argv, "+d");
    while ((c = master_getopt(master_service)) > 0) {
        switch (c) {
        case 'd':
            drop_to_userdb_privileges = TRUE;
            break;
        default:
            return FATAL_DEFAULT;
        }
    }
    argc -= optind;
    argv += optind;

    master_service_init_log(master_service, "script-login: ");

    if (!drop_to_userdb_privileges &&
        (flags & MASTER_SERVICE_FLAG_STANDALONE) == 0) {
        /* drop to privileges defined by service settings */
        restrict_access_by_env(NULL, FALSE);
    }

    master_service_init_finish(master_service);
    master_service_set_service_count(master_service, 1);

    if ((flags & MASTER_SERVICE_FLAG_STANDALONE) != 0) {
        /* The last post-login script is calling us to finish login */
        script_execute_finish();
    } else {
        if (argv[0] == NULL)
            i_fatal("Missing script path");
        exec_args = i_new(const char *, argc + 2);
        for (i = 0; i < argc; i++)
            exec_args[i] = argv[i];
        exec_args[i] = PKG_LIBEXECDIR"/script-login";
        exec_args[i+1] = NULL;

        if (exec_args[0][0] != '/') {
            exec_args[0] = t_strconcat(PKG_LIBEXECDIR"/",
                           exec_args[0], NULL);
        }

        master_service_run(master_service, client_connected);
    }
    master_service_deinit(&master_service);
        return 0;
}