src/lib-auth/auth-server-connection.c

	auth-server-connection.c revision fd05c47210cad1f6d8effbda5cba7f7d938ca9a0
/* Copyright (c) 2003-2014 Dovecot authors, see the included COPYING file */

#include "lib.h"
#include "array.h"
#include "hash.h"
#include "hostpid.h"
#include "ioloop.h"
#include "istream.h"
#include "ostream.h"
#include "net.h"
#include "eacces-error.h"
#include "auth-client-private.h"
#include "auth-client-request.h"
#include "auth-server-connection.h"

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

#define AUTH_SERVER_CONN_MAX_LINE_LENGTH AUTH_CLIENT_MAX_LINE_LENGTH
#define AUTH_HANDSHAKE_TIMEOUT (30*1000)
#define AUTH_SERVER_RECONNECT_TIMEOUT_SECS 5

static void
auth_server_connection_reconnect(struct auth_server_connection *conn,
                 const char *disconnect_reason);

static int
auth_server_input_mech(struct auth_server_connection *conn,
               const char *const *args)
{
    struct auth_mech_desc mech_desc;

    if (conn->handshake_received) {
        i_error("BUG: Authentication server already sent handshake");
        return -1;
    }
    if (args[0] == NULL) {
        i_error("BUG: Authentication server sent broken MECH line");
        return -1;
    }

    memset(&mech_desc, 0, sizeof(mech_desc));
    mech_desc.name = p_strdup(conn->pool, args[0]);

    if (strcmp(mech_desc.name, "PLAIN") == 0)
        conn->has_plain_mech = TRUE;

    for (args++; *args != NULL; args++) {
        if (strcmp(*args, "private") == 0)
            mech_desc.flags |= MECH_SEC_PRIVATE;
        else if (strcmp(*args, "anonymous") == 0)
            mech_desc.flags |= MECH_SEC_ANONYMOUS;
        else if (strcmp(*args, "plaintext") == 0)
            mech_desc.flags |= MECH_SEC_PLAINTEXT;
        else if (strcmp(*args, "dictionary") == 0)
            mech_desc.flags |= MECH_SEC_DICTIONARY;
        else if (strcmp(*args, "active") == 0)
            mech_desc.flags |= MECH_SEC_ACTIVE;
        else if (strcmp(*args, "forward-secrecy") == 0)
            mech_desc.flags |= MECH_SEC_FORWARD_SECRECY;
        else if (strcmp(*args, "mutual-auth") == 0)
            mech_desc.flags |= MECH_SEC_MUTUAL_AUTH;
    }
    array_append(&conn->available_auth_mechs, &mech_desc, 1);
    return 0;
}

static int
auth_server_input_spid(struct auth_server_connection *conn,
               const char *const *args)
{
    if (conn->handshake_received) {
        i_error("BUG: Authentication server already sent handshake");
        return -1;
    }

    if (str_to_uint(args[0], &conn->server_pid) < 0) {
        i_error("BUG: Authentication server sent invalid PID");
        return -1;
    }
    return 0;
}

static int
auth_server_input_cuid(struct auth_server_connection *conn,
               const char *const *args)
{
    if (conn->handshake_received) {
        i_error("BUG: Authentication server already sent handshake");
        return -1;
    }
    if (args[0] == NULL ||
        str_to_uint(args[0], &conn->connect_uid) < 0) {
        i_error("BUG: Authentication server sent broken CUID line");
        return -1;
    }
    return 0;
}

static int
auth_server_input_cookie(struct auth_server_connection *conn,
             const char *const *args)
{
    if (conn->cookie != NULL) {
        i_error("BUG: Authentication server already sent cookie");
        return -1;
    }
    conn->cookie = p_strdup(conn->pool, args[0]);
    return 0;
}

static int auth_server_input_done(struct auth_server_connection *conn)
{
    if (array_count(&conn->available_auth_mechs) == 0) {
        i_error("BUG: Authentication server returned no mechanisms");
        return -1;
    }
    if (conn->cookie == NULL) {
        i_error("BUG: Authentication server didn't send a cookie");
        return -1;
    }

    if (conn->to != NULL)
        timeout_remove(&conn->to);

    conn->handshake_received = TRUE;
    if (conn->client->connect_notify_callback != NULL) {
        conn->client->connect_notify_callback(conn->client, TRUE,
                conn->client->connect_notify_context);
    }
    return 0;
}

static int
auth_server_lookup_request(struct auth_server_connection *conn,
               const char *id_arg, bool remove,
               struct auth_client_request **request_r)
{
    struct auth_client_request *request;
    unsigned int id;

    if (id_arg == NULL || str_to_uint(id_arg, &id) < 0) {
        i_error("BUG: Authentication server input missing ID");
        return -1;
    }

    request = hash_table_lookup(conn->requests, POINTER_CAST(id));
    if (request == NULL) {
        i_error("BUG: Authentication server sent unknown id %u", id);
        return -1;
    }
    if (remove || auth_client_request_is_aborted(request))
        hash_table_remove(conn->requests, POINTER_CAST(id));

    *request_r = request;
    return 0;
}

static int
auth_server_input_ok(struct auth_server_connection *conn,
             const char *const *args)
{
    struct auth_client_request *request;

    if (auth_server_lookup_request(conn, args[0], TRUE, &request) < 0)
        return -1;
    auth_client_request_server_input(request, AUTH_REQUEST_STATUS_OK,
                     args + 1);
    return 0;
}

static int auth_server_input_cont(struct auth_server_connection *conn,
                  const char *const *args)
{
    struct auth_client_request *request;

    if (str_array_length(args) < 2) {
        i_error("BUG: Authentication server sent broken CONT line");
        return -1;
    }

    if (auth_server_lookup_request(conn, args[0], FALSE, &request) < 0)
        return -1;
    auth_client_request_server_input(request, AUTH_REQUEST_STATUS_CONTINUE,
                     args + 1);
    return 0;
}

static int auth_server_input_fail(struct auth_server_connection *conn,
                  const char *const *args)
{
    struct auth_client_request *request;

    if (auth_server_lookup_request(conn, args[0], TRUE, &request) < 0)
        return -1;
    auth_client_request_server_input(request, AUTH_REQUEST_STATUS_FAIL,
                     args + 1);
    return 0;
}

static int
auth_server_connection_input_line(struct auth_server_connection *conn,
                  const char *line)
{
    const char *const *args;

    if (conn->client->debug)
        i_debug("auth input: %s", line);

    args = t_strsplit_tab(line);
    if (args[0] == NULL) {
        i_error("Auth server sent empty line");
        return -1;
    }
    if (strcmp(args[0], "OK") == 0)
        return auth_server_input_ok(conn, args + 1);
    else if (strcmp(args[0], "CONT") == 0)
        return auth_server_input_cont(conn, args + 1);
    else if (strcmp(args[0], "FAIL") == 0)
        return auth_server_input_fail(conn, args + 1);
    else if (strcmp(args[0], "MECH") == 0)
        return auth_server_input_mech(conn, args + 1);
    else if (strcmp(args[0], "SPID") == 0)
        return auth_server_input_spid(conn, args + 1);
    else if (strcmp(args[0], "CUID") == 0)
        return auth_server_input_cuid(conn, args + 1);
    else if (strcmp(args[0], "COOKIE") == 0)
        return auth_server_input_cookie(conn, args + 1);
    else if (strcmp(args[0], "DONE") == 0)
        return auth_server_input_done(conn);
    else {
        i_error("Auth server sent unknown command: %s", args[0]);
        return -1;
    }
}

static void auth_server_connection_input(struct auth_server_connection *conn)
{
    struct istream *input;
    const char *line, *error;
    int ret;

    switch (i_stream_read(conn->input)) {
    case 0:
        return;
    case -1:
        /* disconnected */
        error = conn->input->stream_errno != 0 ?
            strerror(conn->input->stream_errno) : "EOF";
        auth_server_connection_reconnect(conn, error);
        return;
    case -2:
        /* buffer full - can't happen unless auth is buggy */
        i_error("BUG: Auth server sent us more than %d bytes of data",
            AUTH_SERVER_CONN_MAX_LINE_LENGTH);
        auth_server_connection_disconnect(conn, "buffer full");
        return;
    }

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

        /* make sure the major version matches */
        if (strncmp(line, "VERSION\t", 8) != 0 ||
            !str_uint_equals(t_strcut(line + 8, '\t'),
                     AUTH_CLIENT_PROTOCOL_MAJOR_VERSION)) {
            i_error("Authentication server not compatible with "
                "this client (mixed old and new binaries?)");
            auth_server_connection_disconnect(conn,
                "incompatible serevr");
            return;
        }
        conn->version_received = TRUE;
    }

    input = conn->input;
    i_stream_ref(input);
    while ((line = i_stream_next_line(input)) != NULL && !input->closed) {
        T_BEGIN {
            ret = auth_server_connection_input_line(conn, line);
        } T_END;

        if (ret < 0) {
            auth_server_connection_disconnect(conn, t_strdup_printf(
                "Received broken input: %s", line));
            break;
        }
    }
    i_stream_unref(&input);
}

struct auth_server_connection *
auth_server_connection_init(struct auth_client *client)
{
    struct auth_server_connection *conn;
    pool_t pool;

    pool = pool_alloconly_create("auth server connection", 1024);
    conn = p_new(pool, struct auth_server_connection, 1);
    conn->pool = pool;

    conn->client = client;
    conn->fd = -1;
    hash_table_create_direct(&conn->requests, pool, 100);
    i_array_init(&conn->available_auth_mechs, 8);
    return conn;
}

static void
auth_server_connection_remove_requests(struct auth_server_connection *conn,
                       const char *disconnect_reason)
{
    static const char *const temp_failure_args[] = { "temp", NULL };
    struct hash_iterate_context *iter;
    void *key;
    struct auth_client_request *request;
    time_t created, oldest = 0;
    unsigned int request_count = 0;

    if (hash_table_count(conn->requests) == 0)
        return;

    iter = hash_table_iterate_init(conn->requests);
    while (hash_table_iterate(iter, conn->requests, &key, &request)) {
        if (!auth_client_request_is_aborted(request)) {
            request_count++;
            created = auth_client_request_get_create_time(request);
            if (oldest > created || oldest == 0)
                oldest = created;
        }

        auth_client_request_server_input(request,
            AUTH_REQUEST_STATUS_INTERNAL_FAIL,
            temp_failure_args);
    }
    hash_table_iterate_deinit(&iter);
    hash_table_clear(conn->requests, FALSE);

    if (request_count > 0) {
        i_warning("Auth connection closed with %u pending requests "
              "(max %u secs, pid=%s, %s)", request_count,
              (unsigned int)(ioloop_time - oldest),
              my_pid, disconnect_reason);
    }
}

void auth_server_connection_disconnect(struct auth_server_connection *conn,
                       const char *reason)
{
    conn->handshake_received = FALSE;
    conn->version_received = FALSE;
    conn->has_plain_mech = FALSE;
    conn->server_pid = 0;
    conn->connect_uid = 0;
    conn->cookie = NULL;
    array_clear(&conn->available_auth_mechs);

    if (conn->to != NULL)
        timeout_remove(&conn->to);
    if (conn->io != NULL)
        io_remove(&conn->io);
    if (conn->fd != -1) {
        i_stream_destroy(&conn->input);
        o_stream_destroy(&conn->output);

        if (close(conn->fd) < 0)
            i_error("close(auth server connection) failed: %m");
        conn->fd = -1;
    }

    auth_server_connection_remove_requests(conn, reason);

    if (conn->client->connect_notify_callback != NULL) {
        conn->client->connect_notify_callback(conn->client, FALSE,
                conn->client->connect_notify_context);
    }
}

static void auth_server_reconnect_timeout(struct auth_server_connection *conn)
{
    (void)auth_server_connection_connect(conn);
}

static void
auth_server_connection_reconnect(struct auth_server_connection *conn,
                 const char *disconnect_reason)
{
    time_t next_connect;

    auth_server_connection_disconnect(conn, disconnect_reason);

    next_connect = conn->last_connect + AUTH_SERVER_RECONNECT_TIMEOUT_SECS;
    conn->to = timeout_add(ioloop_time >= next_connect ? 0 :
                   (next_connect - ioloop_time) * 1000,
                   auth_server_reconnect_timeout, conn);
}

void auth_server_connection_deinit(struct auth_server_connection **_conn)
{
        struct auth_server_connection *conn = *_conn;

    *_conn = NULL;

    auth_server_connection_disconnect(conn, "deinitializing");
    i_assert(hash_table_count(conn->requests) == 0);
    hash_table_destroy(&conn->requests);
    array_free(&conn->available_auth_mechs);
    pool_unref(&conn->pool);
}

static void auth_client_handshake_timeout(struct auth_server_connection *conn)
{
    i_error("Timeout waiting for handshake from auth server. "
        "my pid=%u, input bytes=%"PRIuUOFF_T,
        conn->client->client_pid, conn->input->v_offset);
    auth_server_connection_reconnect(conn, "auth server timeout");
}

int auth_server_connection_connect(struct auth_server_connection *conn)
{
    const char *handshake;
    int fd;

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

    conn->last_connect = ioloop_time;
    if (conn->to != NULL)
        timeout_remove(&conn->to);

    /* max. 1 second wait here. */
    fd = net_connect_unix_with_retries(conn->client->auth_socket_path,
                       1000);
    if (fd == -1) {
        if (errno == EACCES) {
            i_error("auth: %s",
                eacces_error_get("connect",
                    conn->client->auth_socket_path));
        } else {
            i_error("auth: connect(%s) failed: %m",
                conn->client->auth_socket_path);
        }
        return -1;
    }
    conn->fd = fd;
    conn->io = io_add(fd, IO_READ, auth_server_connection_input, conn);
    conn->input = i_stream_create_fd(fd, AUTH_SERVER_CONN_MAX_LINE_LENGTH,
                     FALSE);
    conn->output = o_stream_create_fd(fd, (size_t)-1, FALSE);

    handshake = t_strdup_printf("VERSION\t%u\t%u\nCPID\t%u\n",
                    AUTH_CLIENT_PROTOCOL_MAJOR_VERSION,
                                    AUTH_CLIENT_PROTOCOL_MINOR_VERSION,
                    conn->client->client_pid);
    if (o_stream_send_str(conn->output, handshake) < 0) {
        i_warning("Error sending handshake to auth server: %m");
        auth_server_connection_disconnect(conn,
            strerror(conn->output->last_failed_errno));
        return -1;
    }

    conn->to = timeout_add(AUTH_HANDSHAKE_TIMEOUT,
                   auth_client_handshake_timeout, conn);
    return 0;
}

unsigned int
auth_server_connection_add_request(struct auth_server_connection *conn,
                   struct auth_client_request *request)
{
    unsigned int id;

    id = ++conn->client->request_id_counter;
    if (id == 0) {
        /* wrapped - ID 0 not allowed */
        id = ++conn->client->request_id_counter;
    }
    i_assert(hash_table_lookup(conn->requests, POINTER_CAST(id)) == NULL);
    hash_table_insert(conn->requests, POINTER_CAST(id), request);
    return id;
}