net/rxrpc/krxsecd.c

   1 /* krxsecd.c: Rx security daemon
   2  *
   3  * Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  *
  11  * This daemon deals with:
  12  * - consulting the application as to whether inbound peers and calls should be authorised
  13  * - generating security challenges for inbound connections
  14  * - responding to security challenges on outbound connections
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/sched.h>
  19 #include <linux/completion.h>
  20 #include <linux/spinlock.h>
  21 #include <linux/init.h>
  22 #include <rxrpc/krxsecd.h>
  23 #include <rxrpc/transport.h>
  24 #include <rxrpc/connection.h>
  25 #include <rxrpc/message.h>
  26 #include <rxrpc/peer.h>
  27 #include <rxrpc/call.h>
  28 #include <linux/udp.h>
  29 #include <linux/ip.h>
  30 #include <linux/freezer.h>
  31 #include <net/sock.h>
  32 #include "internal.h"
  33
  34 static DECLARE_WAIT_QUEUE_HEAD(rxrpc_krxsecd_sleepq);
  35 static DECLARE_COMPLETION(rxrpc_krxsecd_dead);
  36 static volatile int rxrpc_krxsecd_die;
  37
  38 static atomic_t rxrpc_krxsecd_qcount;
  39
  40 /* queue of unprocessed inbound messages with seqno #1 and
  41  * RXRPC_CLIENT_INITIATED flag set */
  42 static LIST_HEAD(rxrpc_krxsecd_initmsgq);
  43 static DEFINE_SPINLOCK(rxrpc_krxsecd_initmsgq_lock);
  44
  45 static void rxrpc_krxsecd_process_incoming_call(struct rxrpc_message *msg);
  46
  47 /*****************************************************************************/
  48 /*
  49  * Rx security daemon
  50  */
  51 static int rxrpc_krxsecd(void *arg)
  52 {
  53         DECLARE_WAITQUEUE(krxsecd, current);
  54
  55         int die;
  56
  57         printk("Started krxsecd %d\n", current->pid);
  58
  59         daemonize("krxsecd");
  60
  61         /* loop around waiting for work to do */
  62         do {
  63                 /* wait for work or to be told to exit */
  64                 _debug("### Begin Wait");
  65                 if (!atomic_read(&rxrpc_krxsecd_qcount)) {
  66                         set_current_state(TASK_INTERRUPTIBLE);
  67
  68                         add_wait_queue(&rxrpc_krxsecd_sleepq, &krxsecd);
  69
  70                         for (;;) {
  71                                 set_current_state(TASK_INTERRUPTIBLE);
  72                                 if (atomic_read(&rxrpc_krxsecd_qcount) ||
  73                                     rxrpc_krxsecd_die ||
  74                                     signal_pending(current))
  75                                         break;
  76
  77                                 schedule();
  78                         }
  79
  80                         remove_wait_queue(&rxrpc_krxsecd_sleepq, &krxsecd);
  81                         set_current_state(TASK_RUNNING);
  82                 }
  83                 die = rxrpc_krxsecd_die;
  84                 _debug("### End Wait");
  85
  86                 /* see if there're incoming calls in need of authenticating */
  87                 _debug("### Begin Inbound Calls");
  88
  89                 if (!list_empty(&rxrpc_krxsecd_initmsgq)) {
  90                         struct rxrpc_message *msg = NULL;
  91
  92                         spin_lock(&rxrpc_krxsecd_initmsgq_lock);
  93
  94                         if (!list_empty(&rxrpc_krxsecd_initmsgq)) {
  95                                 msg = list_entry(rxrpc_krxsecd_initmsgq.next,
  96                                                  struct rxrpc_message, link);
  97                                 list_del_init(&msg->link);
  98                                 atomic_dec(&rxrpc_krxsecd_qcount);
  99                         }
 100
 101                         spin_unlock(&rxrpc_krxsecd_initmsgq_lock);
 102
 103                         if (msg) {
 104                                 rxrpc_krxsecd_process_incoming_call(msg);
 105                                 rxrpc_put_message(msg);
 106                         }
 107                 }
 108
 109                 _debug("### End Inbound Calls");
 110
 111                 try_to_freeze();
 112
 113                 /* discard pending signals */
 114                 rxrpc_discard_my_signals();
 115
 116         } while (!die);
 117
 118         /* and that's all */
 119         complete_and_exit(&rxrpc_krxsecd_dead, 0);
 120
 121 } /* end rxrpc_krxsecd() */
 122
 123 /*****************************************************************************/
 124 /*
 125  * start up a krxsecd daemon
 126  */
 127 int __init rxrpc_krxsecd_init(void)
 128 {
 129         return kernel_thread(rxrpc_krxsecd, NULL, 0);
 130
 131 } /* end rxrpc_krxsecd_init() */
 132
 133 /*****************************************************************************/
 134 /*
 135  * kill the krxsecd daemon and wait for it to complete
 136  */
 137 void rxrpc_krxsecd_kill(void)
 138 {
 139         rxrpc_krxsecd_die = 1;
 140         wake_up_all(&rxrpc_krxsecd_sleepq);
 141         wait_for_completion(&rxrpc_krxsecd_dead);
 142
 143 } /* end rxrpc_krxsecd_kill() */
 144
 145 /*****************************************************************************/
 146 /*
 147  * clear all pending incoming calls for the specified transport
 148  */
 149 void rxrpc_krxsecd_clear_transport(struct rxrpc_transport *trans)
 150 {
 151         LIST_HEAD(tmp);
 152
 153         struct rxrpc_message *msg;
 154         struct list_head *_p, *_n;
 155
 156         _enter("%p",trans);
 157
 158         /* move all the messages for this transport onto a temp list */
 159         spin_lock(&rxrpc_krxsecd_initmsgq_lock);
 160
 161         list_for_each_safe(_p, _n, &rxrpc_krxsecd_initmsgq) {
 162                 msg = list_entry(_p, struct rxrpc_message, link);
 163                 if (msg->trans == trans) {
 164                         list_move_tail(&msg->link, &tmp);
 165                         atomic_dec(&rxrpc_krxsecd_qcount);
 166                 }
 167         }
 168
 169         spin_unlock(&rxrpc_krxsecd_initmsgq_lock);
 170
 171         /* zap all messages on the temp list */
 172         while (!list_empty(&tmp)) {
 173                 msg = list_entry(tmp.next, struct rxrpc_message, link);
 174                 list_del_init(&msg->link);
 175                 rxrpc_put_message(msg);
 176         }
 177
 178         _leave("");
 179 } /* end rxrpc_krxsecd_clear_transport() */
 180
 181 /*****************************************************************************/
 182 /*
 183  * queue a message on the incoming calls list
 184  */
 185 void rxrpc_krxsecd_queue_incoming_call(struct rxrpc_message *msg)
 186 {
 187         _enter("%p", msg);
 188
 189         /* queue for processing by krxsecd */
 190         spin_lock(&rxrpc_krxsecd_initmsgq_lock);
 191
 192         if (!rxrpc_krxsecd_die) {
 193                 rxrpc_get_message(msg);
 194                 list_add_tail(&msg->link, &rxrpc_krxsecd_initmsgq);
 195                 atomic_inc(&rxrpc_krxsecd_qcount);
 196         }
 197
 198         spin_unlock(&rxrpc_krxsecd_initmsgq_lock);
 199
 200         wake_up(&rxrpc_krxsecd_sleepq);
 201
 202         _leave("");
 203 } /* end rxrpc_krxsecd_queue_incoming_call() */
 204
 205 /*****************************************************************************/
 206 /*
 207  * process the initial message of an incoming call
 208  */
 209 void rxrpc_krxsecd_process_incoming_call(struct rxrpc_message *msg)
 210 {
 211         struct rxrpc_transport *trans = msg->trans;
 212         struct rxrpc_service *srv;
 213         struct rxrpc_call *call;
 214         struct list_head *_p;
 215         unsigned short sid;
 216         int ret;
 217
 218         _enter("%p{tr=%p}", msg, trans);
 219
 220         ret = rxrpc_incoming_call(msg->conn, msg, &call);
 221         if (ret < 0)
 222                 goto out;
 223
 224         /* find the matching service on the transport */
 225         sid = ntohs(msg->hdr.serviceId);
 226         srv = NULL;
 227
 228         spin_lock(&trans->lock);
 229         list_for_each(_p, &trans->services) {
 230                 srv = list_entry(_p, struct rxrpc_service, link);
 231                 if (srv->service_id == sid && try_module_get(srv->owner)) {
 232                         /* found a match (made sure it won't vanish) */
 233                         _debug("found service '%s'", srv->name);
 234                         call->owner = srv->owner;
 235                         break;
 236                 }
 237         }
 238         spin_unlock(&trans->lock);
 239
 240         /* report the new connection
 241          * - the func must inc the call's usage count to keep it
 242          */
 243         ret = -ENOENT;
 244         if (_p != &trans->services) {
 245                 /* attempt to accept the call */
 246                 call->conn->service = srv;
 247                 call->app_attn_func = srv->attn_func;
 248                 call->app_error_func = srv->error_func;
 249                 call->app_aemap_func = srv->aemap_func;
 250
 251                 ret = srv->new_call(call);
 252
 253                 /* send an abort if an error occurred */
 254                 if (ret < 0) {
 255                         rxrpc_call_abort(call, ret);
 256                 }
 257                 else {
 258                         /* formally receive and ACK the new packet */
 259                         ret = rxrpc_conn_receive_call_packet(call->conn,
 260                                                              call, msg);
 261                 }
 262         }
 263
 264         rxrpc_put_call(call);
 265  out:
 266         if (ret < 0)
 267                 rxrpc_trans_immediate_abort(trans, msg, ret);
 268
 269         _leave(" (%d)", ret);
 270 } /* end rxrpc_krxsecd_process_incoming_call() */