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Commit e4847021 authored by Tilman Schmidt's avatar Tilman Schmidt Committed by David S. Miller
Browse files

isdn: avoid races in capidrv 



In several places, capidrv sends a CAPI message to the ISDN
device and then updates its internal state accordingly.
If the response message from the device arrives before the
state is updated, it may be rejected or processed incorrectly.
Avoid these races by updating the state before emitting the
message.

Impact: bugfix
Signed-off-by: default avatarTilman Schmidt <tilman@imap.cc>
Acked-by: default avatarKarsten Keil <keil@b1-systems.de>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 812d7347

drivers/isdn/capi/capidrv.c

+13 −12
Original line number Diff line number Diff line
@@ -671,8 +671,8 @@ static void n0(capidrv_contr * card, capidrv_ncci * ncci) 
				 NULL,	/* Useruserdata */   /* $$$$ */

				 NULL	/* Facilitydataarray */

	);

	send_message(card, &cmsg);

	plci_change_state(card, ncci->plcip, EV_PLCI_DISCONNECT_REQ);

	send_message(card, &cmsg);



	cmd.command = ISDN_STAT_BHUP;

	cmd.driver = card->myid;
@@ -924,8 +924,8 @@ static void handle_incoming_call(capidrv_contr * card, _cmsg * cmsg) 
		 */

		capi_cmsg_answer(cmsg);

		cmsg->Reject = 1;	/* ignore */

		send_message(card, cmsg);

		plci_change_state(card, plcip, EV_PLCI_CONNECT_REJECT);

		send_message(card, cmsg);

		printk(KERN_INFO "capidrv-%d: incoming call %s,%d,%d,%s ignored\n",

			card->contrnr,

			cmd.parm.setup.phone,
@@ -974,8 +974,8 @@ static void handle_incoming_call(capidrv_contr * card, _cmsg * cmsg) 
	case 2:		/* Call will be rejected. */

		capi_cmsg_answer(cmsg);

		cmsg->Reject = 2;	/* reject call, normal call clearing */

		send_message(card, cmsg);

		plci_change_state(card, plcip, EV_PLCI_CONNECT_REJECT);

		send_message(card, cmsg);

		break;



	default:
@@ -983,8 +983,8 @@ static void handle_incoming_call(capidrv_contr * card, _cmsg * cmsg) 
		capi_cmsg_answer(cmsg);

		cmsg->Reject = 8;	/* reject call,

					   destination out of order */

		send_message(card, cmsg);

		plci_change_state(card, plcip, EV_PLCI_CONNECT_REJECT);

		send_message(card, cmsg);

		break;

	}

	return;
@@ -1020,8 +1020,8 @@ static void handle_plci(_cmsg * cmsg) 
		card->bchans[plcip->chan].disconnecting = 1;

		plci_change_state(card, plcip, EV_PLCI_DISCONNECT_IND);

		capi_cmsg_answer(cmsg);

		send_message(card, cmsg);

		plci_change_state(card, plcip, EV_PLCI_DISCONNECT_RESP);

		send_message(card, cmsg);

		break;



	case CAPI_DISCONNECT_CONF:	/* plci */
@@ -1078,8 +1078,8 @@ static void handle_plci(_cmsg * cmsg) 


		if (card->bchans[plcip->chan].incoming) {

			capi_cmsg_answer(cmsg);

			send_message(card, cmsg);

			plci_change_state(card, plcip, EV_PLCI_CONNECT_ACTIVE_IND);

			send_message(card, cmsg);

		} else {

			capidrv_ncci *nccip;

			capi_cmsg_answer(cmsg);
@@ -1098,13 +1098,14 @@ static void handle_plci(_cmsg * cmsg) 
						 NULL	/* NCPI */

			);

			nccip->msgid = cmsg->Messagenumber;

			plci_change_state(card, plcip,

					  EV_PLCI_CONNECT_ACTIVE_IND);

			ncci_change_state(card, nccip, EV_NCCI_CONNECT_B3_REQ);

			send_message(card, cmsg);

			cmd.command = ISDN_STAT_DCONN;

			cmd.driver = card->myid;

			cmd.arg = plcip->chan;

			card->interface.statcallb(&cmd);

			plci_change_state(card, plcip, EV_PLCI_CONNECT_ACTIVE_IND);

			ncci_change_state(card, nccip, EV_NCCI_CONNECT_B3_REQ);

		}

		break;
@@ -1193,8 +1194,8 @@ static void handle_ncci(_cmsg * cmsg) 
			goto notfound;



		capi_cmsg_answer(cmsg);

		send_message(card, cmsg);

		ncci_change_state(card, nccip, EV_NCCI_CONNECT_B3_ACTIVE_IND);

		send_message(card, cmsg);



		cmd.command = ISDN_STAT_BCONN;

		cmd.driver = card->myid;
@@ -1222,8 +1223,8 @@ static void handle_ncci(_cmsg * cmsg) 
							  0,	/* Reject */

							  NULL	/* NCPI */

				);

				send_message(card, cmsg);

				ncci_change_state(card, nccip, EV_NCCI_CONNECT_B3_RESP);

				send_message(card, cmsg);

				break;

			}

			printk(KERN_ERR "capidrv-%d: no mem for ncci, sorry\n",							card->contrnr);
@@ -1299,8 +1300,8 @@ static void handle_ncci(_cmsg * cmsg) 
		card->bchans[nccip->chan].disconnecting = 1;

		ncci_change_state(card, nccip, EV_NCCI_DISCONNECT_B3_IND);

		capi_cmsg_answer(cmsg);

		send_message(card, cmsg);

		ncci_change_state(card, nccip, EV_NCCI_DISCONNECT_B3_RESP);

		send_message(card, cmsg);

		break;



	case CAPI_DISCONNECT_B3_CONF:	/* ncci */
@@ -2014,8 +2015,8 @@ static void send_listen(capidrv_contr *card) 
			     card->cipmask,

			     card->cipmask2,

			     NULL, NULL);

	send_message(card, &cmdcmsg);

	listen_change_state(card, EV_LISTEN_REQ);

	send_message(card, &cmdcmsg);

}



static void listentimerfunc(unsigned long x)