netdev - [PATCH 3/4] isdn: avoid races in capidrv (v2)

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <20090919-patch-capi-3.tilman@imap.cc>
Date:	Sat, 19 Sep 2009 01:57:42 +0200 (CEST)
From:	Tilman Schmidt <tilman@...p.cc>
To:	Karsten Keil <isdn@...ux-pingi.de>,
	Karsten Keil <keil@...systems.de>
CC:	davem@...emloft.net, i4ldeveloper@...tserv.isdn4linux.de,
	netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 3/4] isdn: avoid races in capidrv (v2)

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.

Signed-off-by: Tilman Schmidt <tilman@...p.cc>
---
 drivers/isdn/capi/capidrv.c |   25 +++++++++++++------------
 1 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/drivers/isdn/capi/capidrv.c b/drivers/isdn/capi/capidrv.c
index 6501202..4921eae 100644
--- a/drivers/isdn/capi/capidrv.c
+++ b/drivers/isdn/capi/capidrv.c
@@ -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)
-- 
1.6.2.1.214.ge986c

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html