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authorMarcel Holtmann <marcel@holtmann.org>2007-01-08 02:16:23 +0100
committerDavid S. Miller <davem@sunset.davemloft.net>2007-01-09 00:29:53 -0800
commitf4777569204cb59f2f04fbe9ef4e9a6918209104 (patch)
treec42ce096df9584d4c83b7003c7bbbd8c30be970d /net
parentd2e7543c41755f4ec75385536b109d5f084fe734 (diff)
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[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 <marcel@holtmann.org>
Diffstat (limited to 'net')
-rw-r--r--net/bluetooth/cmtp/capi.c39
1 files changed, 33 insertions, 6 deletions
diff --git a/net/bluetooth/cmtp/capi.c b/net/bluetooth/cmtp/capi.c
index be04e9fb11f..ab166b48ce8 100644
--- a/net/bluetooth/cmtp/capi.c
+++ b/net/bluetooth/cmtp/capi.c
@@ -196,6 +196,9 @@ static void cmtp_recv_interopmsg(struct cmtp_session *session, struct sk_buff *s
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 cmtp_session *session, struct sk_buff *s
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 cmtp_session *session, struct sk_buff *s
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 cmtp_session *session, struct sk_buff *s
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 cmtp_session *session, struct sk_buff *s
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_session *session, struct sk_buff *skb)
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;