src/lib-auth/auth-master.c

	auth-master.c revision 52d058e5234181fca90048d5904a151a1ccc8a6b
/* Copyright (c) 2005-2008 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "lib-signals.h"
#include "array.h"
#include "ioloop.h"
#include "network.h"
#include "istream.h"
#include "ostream.h"
#include "auth-master.h"

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

#define AUTH_PROTOCOL_MAJOR 1
#define AUTH_PROTOCOL_MINOR 0

#define AUTH_REQUEST_TIMEOUT_SECS 30
#define AUTH_MASTER_IDLE_SECS 60

#define MAX_INBUF_SIZE 8192
#define MAX_OUTBUF_SIZE 1024

struct auth_master_connection {
    char *auth_socket_path;

    int fd;
    struct ioloop *ioloop;
    struct io *io;
    struct istream *input;
    struct ostream *output;
    struct timeout *to;

    unsigned int request_counter;
    pool_t pool;
    const char *user;
    struct auth_user_reply *user_reply;
    int return_value;

    unsigned int debug:1;
    unsigned int sent_handshake:1;
    unsigned int handshaked:1;
    unsigned int aborted:1;
};

static void auth_input(struct auth_master_connection *conn);

struct auth_master_connection *
auth_master_init(const char *auth_socket_path, bool debug)
{
    struct auth_master_connection *conn;

    conn = i_new(struct auth_master_connection, 1);
    conn->auth_socket_path = i_strdup(auth_socket_path);
    conn->fd = -1;
    conn->debug = debug;
    return conn;
}

static void auth_connection_close(struct auth_master_connection *conn)
{
    if (conn->to != NULL)
        timeout_remove(&conn->to);
    if (conn->fd != -1) {
        if (close(conn->fd) < 0)
            i_error("close(%s) failed: %m", conn->auth_socket_path);
        conn->fd = -1;
    }

    conn->sent_handshake = FALSE;
    conn->handshaked = FALSE;
}

void auth_master_deinit(struct auth_master_connection **_conn)
{
    struct auth_master_connection *conn = *_conn;

    *_conn = NULL;
    auth_connection_close(conn);
    i_free(conn->auth_socket_path);
    i_free(conn);
}

static void auth_request_lookup_abort(struct auth_master_connection *conn)
{
    io_loop_stop(conn->ioloop);
    conn->aborted = TRUE;
}

static void auth_parse_input(struct auth_master_connection *conn,
                 const char *const *args)
{
    struct auth_user_reply *reply = conn->user_reply;

    memset(reply, 0, sizeof(*reply));
    reply->uid = (uid_t)-1;
    reply->gid = (gid_t)-1;
    p_array_init(&reply->extra_fields, conn->pool, 64);

    reply->user = p_strdup(conn->pool, *args);
    for (args++; *args != NULL; args++) {
        if (conn->debug)
            i_info("auth input: %s", *args);

        if (strncmp(*args, "uid=", 4) == 0)
            reply->uid = strtoul(*args + 4, NULL, 10);
        else if (strncmp(*args, "gid=", 4) == 0)
            reply->gid = strtoul(*args + 4, NULL, 10);
        else if (strncmp(*args, "home=", 5) == 0)
            reply->home = p_strdup(conn->pool, *args + 5);
        else if (strncmp(*args, "chroot=", 7) == 0)
            reply->chroot = p_strdup(conn->pool, *args + 7);
        else {
            const char *field = p_strdup(conn->pool, *args);
            array_append(&reply->extra_fields, &field, 1);
        }
    }
}

static int auth_input_handshake(struct auth_master_connection *conn)
{
    const char *line, *const *tmp;

    while ((line = i_stream_next_line(conn->input)) != NULL) {
        tmp = t_strsplit(line, "\t");
        if (strcmp(tmp[0], "VERSION") == 0 &&
            tmp[1] != NULL && tmp[2] != NULL) {
            if (strcmp(tmp[1], dec2str(AUTH_PROTOCOL_MAJOR)) != 0) {
                i_error("userdb lookup(%s): "
                    "Auth protocol version mismatch "
                    "(%s vs %d)", conn->user, tmp[1],
                    AUTH_PROTOCOL_MAJOR);
                auth_request_lookup_abort(conn);
                return -1;
            }
        } else if (strcmp(tmp[0], "SPID") == 0) {
            conn->handshaked = TRUE;
            break;
        }
    }
    return 0;
}

static void auth_input(struct auth_master_connection *conn)
{
    const char *line, *cmd, *const *args, *id, *wanted_id;

    switch (i_stream_read(conn->input)) {
    case 0:
        return;
    case -1:
        /* disconnected */
        i_error("userdb lookup(%s): Disconnected unexpectedly",
            conn->user);
        auth_request_lookup_abort(conn);
        return;
    case -2:
        /* buffer full */
        i_error("userdb lookup(%s): BUG: Received more than %d bytes",
            conn->user, MAX_INBUF_SIZE);
        auth_request_lookup_abort(conn);
        return;
    }

    if (!conn->handshaked) {
        if (auth_input_handshake(conn) < 0)
            return;
    }

    line = i_stream_next_line(conn->input);
    if (line == NULL)
        return;

    args = t_strsplit(line, "\t");
    cmd = *args; args++;
    if (*args == NULL)
        id = "";
    else {
        id = *args;
        args++;
    }

    wanted_id = dec2str(conn->request_counter);
    if (strcmp(id, wanted_id) == 0) {
        io_loop_stop(conn->ioloop);
        if (strcmp(cmd, "USER") == 0) {
            auth_parse_input(conn, args);
            conn->return_value = 1;
            return;
        }
        if (strcmp(cmd, "NOTFOUND") == 0) {
            conn->return_value = 0;
            return;
        }
        if (strcmp(cmd, "FAIL") == 0) {
            i_error("userdb lookup(%s) failed: %s",
                conn->user, *args != NULL ? *args :
                "Internal failure");
            return;
        }
    }

    if (strcmp(cmd, "CUID") == 0) {
        i_error("userdb lookup(%s): %s is an auth client socket. "
            "It should be a master socket.",
            conn->user, conn->auth_socket_path);
    } else {
        i_error("userdb lookup(%s): BUG: Unexpected input: %s",
            conn->user, line);
    }
    auth_request_lookup_abort(conn);
}

static int auth_master_connect(struct auth_master_connection *conn)
{
    int fd, try;

    i_assert(conn->fd == -1);

    /* max. 1 second wait here. */
    for (try = 0; try < 10; try++) {
        fd = net_connect_unix(conn->auth_socket_path);
        if (fd != -1 || (errno != EAGAIN && errno != ECONNREFUSED))
            break;

        /* busy. wait for a while. */
        usleep(((rand() % 10) + 1) * 10000);
    }
    if (fd == -1) {
        i_error("userdb lookup: connect(%s) failed: %m",
            conn->auth_socket_path);
        return -1;
    }
    conn->fd = fd;
    return 0;
}

static void auth_request_timeout(struct auth_master_connection *conn)
{
    if (!conn->handshaked)
        i_error("userdb lookup(%s): Connecting timed out", conn->user);
    else
        i_error("userdb lookup(%s): Request timed out", conn->user);
    auth_request_lookup_abort(conn);
}

static void auth_idle_timeout(struct auth_master_connection *conn)
{
    auth_connection_close(conn);
}

static void auth_master_set_io(struct auth_master_connection *conn)
{
    if (conn->to != NULL)
        timeout_remove(&conn->to);

    conn->ioloop = io_loop_create();
    conn->input = i_stream_create_fd(conn->fd, MAX_INBUF_SIZE, FALSE);
    conn->output = o_stream_create_fd(conn->fd, MAX_OUTBUF_SIZE, FALSE);
    conn->io = io_add(conn->fd, IO_READ, auth_input, conn);
    conn->to = timeout_add(1000*AUTH_REQUEST_TIMEOUT_SECS,
                   auth_request_timeout, conn);
    lib_signals_reset_ioloop();
}

static void auth_master_unset_io(struct auth_master_connection *conn,
                 struct ioloop *prev_ioloop)
{
    io_loop_set_current(prev_ioloop);
    lib_signals_reset_ioloop();
    io_loop_set_current(conn->ioloop);

    timeout_remove(&conn->to);
    io_remove(&conn->io);
    i_stream_unref(&conn->input);
    o_stream_unref(&conn->output);
    io_loop_destroy(&conn->ioloop);

    conn->to = timeout_add(1000*AUTH_MASTER_IDLE_SECS,
                   auth_idle_timeout, conn);
}

static bool is_valid_string(const char *str)
{
    const char *p;

    /* make sure we're not sending any characters that have a special
       meaning. */
    for (p = str; *p != '\0'; p++) {
        if (*p == '\t' || *p == '\n' || *p == '\r')
            return FALSE;
    }
    return TRUE;
}

int auth_master_user_lookup(struct auth_master_connection *conn,
                const char *user, const char *service,
                pool_t pool, struct auth_user_reply *reply_r)
{
    struct ioloop *prev_ioloop;
    const char *str;

    if (!is_valid_string(user) || !is_valid_string(service)) {
        /* non-allowed characters, the user can't exist */
        return 0;
    }
    if (conn->fd == -1) {
        if (auth_master_connect(conn) < 0)
            return -1;
    }

    prev_ioloop = current_ioloop;
    auth_master_set_io(conn);
    conn->return_value = -1;
    conn->pool = pool;
    conn->user = user;
    conn->user_reply = reply_r;
    if (++conn->request_counter == 0) {
        /* avoid zero */
        conn->request_counter++;
    }

    o_stream_cork(conn->output);
    if (!conn->sent_handshake) {
        str = t_strdup_printf("VERSION\t%d\t%d\n",
                      AUTH_PROTOCOL_MAJOR, AUTH_PROTOCOL_MINOR);
        o_stream_send_str(conn->output, str);
        conn->sent_handshake = TRUE;
    }

    str = t_strdup_printf("USER\t%u\t%s\tservice=%s\n",
                  conn->request_counter, user, service);
    o_stream_send_str(conn->output, str);
    o_stream_uncork(conn->output);

    if (conn->output->stream_errno != 0) {
        errno = conn->output->stream_errno;
        i_error("write(auth socket) failed: %m");
    } else {
        io_loop_run(conn->ioloop);
    }

    auth_master_unset_io(conn, prev_ioloop);
    if (conn->aborted) {
        conn->aborted = FALSE;
        auth_connection_close(conn);
    }
    conn->user = NULL;
    conn->pool = NULL;
    conn->user_reply = NULL;
    return conn->return_value;
}