[patch] patch-bluetooth-cmtp-length-checks

patch-bluetooth-cmtp-length-checks (text/plain), 3.63 KB, created by Sune Kloppenborg Jeppesen (RETIRED) on 2006-12-11 08:08:30 UTC

[Bluetooth] Add packet size checks for CAPI messages

With malformed packets it might be possible to overwrite internal
CMTP and CAPI data structures. This patch adds additional length
checks to prevent these kinds of remote attacks.

Signed-off-by: Marcel Holtmann <[e-mail]>

---
commit b48c561376403b411921ac69e5d06899f1f98f53
tree 833d4389d00f5bf41e005d798d4db79e635a12c8
parent 9202f32558601c2c99ddc438eb3218131d00d413
author Marcel Holtmann <[e-mail]> Mon, 11 Dec 2006 15:02:01 +0100
committer Marcel Holtmann <[e-mail]> Mon, 11 Dec 2006 15:02:01 +0100

 net/bluetooth/cmtp/capi.c |   39 +++++++++++++++++++++++++++++++++------
 1 files changed, 33 insertions(+), 6 deletions(-)

diff --git a/net/bluetooth/cmtp/capi.c b/net/bluetooth/cmtp/capi.c
index be04e9f..ab166b4 100644
--- a/net/bluetooth/cmtp/capi.c
+++ b/net/bluetooth/cmtp/capi.c
@@ -196,6 +196,9 @@ static void cmtp_recv_interopmsg(struct 
 
 	switch (CAPIMSG_SUBCOMMAND(skb->data)) {
 	case CAPI_CONF:
+		if (skb->len < CAPI_MSG_BASELEN + 10)
+			break;
+
 		func = CAPIMSG_U16(skb->data, CAPI_MSG_BASELEN + 5);
 		info = CAPIMSG_U16(skb->data, CAPI_MSG_BASELEN + 8);
 
@@ -226,6 +229,9 @@ static void cmtp_recv_interopmsg(struct 
 			break;
 
 		case CAPI_FUNCTION_GET_PROFILE:
+			if (skb->len < CAPI_MSG_BASELEN + 11 + sizeof(capi_profile))
+				break;
+
 			controller = CAPIMSG_U16(skb->data, CAPI_MSG_BASELEN + 11);
 			msgnum = CAPIMSG_MSGID(skb->data);
 
@@ -246,17 +252,26 @@ static void cmtp_recv_interopmsg(struct 
 			break;
 
 		case CAPI_FUNCTION_GET_MANUFACTURER:
+			if (skb->len < CAPI_MSG_BASELEN + 15)
+				break;
+
 			controller = CAPIMSG_U32(skb->data, CAPI_MSG_BASELEN + 10);
 
 			if (!info && ctrl) {
+				int len = min_t(uint, CAPI_MANUFACTURER_LEN,
+						skb->data[CAPI_MSG_BASELEN + 14]);
+
+				memset(ctrl->manu, 0, CAPI_MANUFACTURER_LEN);
 				strncpy(ctrl->manu,
-					skb->data + CAPI_MSG_BASELEN + 15,
-					skb->data[CAPI_MSG_BASELEN + 14]);
+					skb->data + CAPI_MSG_BASELEN + 15, len);
 			}
 
 			break;
 
 		case CAPI_FUNCTION_GET_VERSION:
+			if (skb->len < CAPI_MSG_BASELEN + 32)
+				break;
+
 			controller = CAPIMSG_U32(skb->data, CAPI_MSG_BASELEN + 12);
 
 			if (!info && ctrl) {
@@ -269,13 +284,18 @@ static void cmtp_recv_interopmsg(struct 
 			break;
 
 		case CAPI_FUNCTION_GET_SERIAL_NUMBER:
+			if (skb->len < CAPI_MSG_BASELEN + 17)
+				break;
+
 			controller = CAPIMSG_U32(skb->data, CAPI_MSG_BASELEN + 12);
 
 			if (!info && ctrl) {
+				int len = min_t(uint, CAPI_SERIAL_LEN,
+						skb->data[CAPI_MSG_BASELEN + 16]);
+
 				memset(ctrl->serial, 0, CAPI_SERIAL_LEN);
 				strncpy(ctrl->serial,
-					skb->data + CAPI_MSG_BASELEN + 17,
-					skb->data[CAPI_MSG_BASELEN + 16]);
+					skb->data + CAPI_MSG_BASELEN + 17, len);
 			}
 
 			break;
@@ -284,14 +304,18 @@ static void cmtp_recv_interopmsg(struct 
 		break;
 
 	case CAPI_IND:
+		if (skb->len < CAPI_MSG_BASELEN + 6)
+			break;
+
 		func = CAPIMSG_U16(skb->data, CAPI_MSG_BASELEN + 3);
 
 		if (func == CAPI_FUNCTION_LOOPBACK) {
+			int len = min_t(uint, skb->len - CAPI_MSG_BASELEN - 6,
+						skb->data[CAPI_MSG_BASELEN + 5]);
 			appl = CAPIMSG_APPID(skb->data);
 			msgnum = CAPIMSG_MSGID(skb->data);
 			cmtp_send_interopmsg(session, CAPI_RESP, appl, msgnum, func,
-						skb->data + CAPI_MSG_BASELEN + 6,
-						skb->data[CAPI_MSG_BASELEN + 5]);
+						skb->data + CAPI_MSG_BASELEN + 6, len);
 		}
 
 		break;
@@ -309,6 +333,9 @@ void cmtp_recv_capimsg(struct cmtp_sessi
 
 	BT_DBG("session %p skb %p len %d", session, skb, skb->len);
 
+	if (skb->len < CAPI_MSG_BASELEN)
+		return;
+
 	if (CAPIMSG_COMMAND(skb->data) == CAPI_INTEROPERABILITY) {
 		cmtp_recv_interopmsg(session, skb);
 		return;