net: wireless: bcmdhd: check packet length for event messages

Check the datalen field is less than the size of
packet received from the network.

Signed-off-by: Patrick Tjin <pattjin@google.com>

Bug: 27335472

[fixes CVE-2016-0802]
Signed-off-by: Kees Cook <keescook@chromium.org>
Change-Id: I87171cf09bb8dc55da21c4d8ee3101f0ed0a9a70

3 files changed, 16 insertions, 5 deletions

diff --git a/drivers/net/wireless/bcmdhd/dhd.h b/drivers/net/wireless/bcmdhd/dhd.h
index 59cdfbed5f6..acdee664457 100644
--- a/drivers/net/wireless/bcmdhd/dhd.h
+++ b/drivers/net/wireless/bcmdhd/dhd.h
@@ -604,7 +604,7 @@ extern int dhd_ifname2idx(struct dhd_info *dhd, char *name);
 extern int dhd_net2idx(struct dhd_info *dhd, struct net_device *net);
 extern struct net_device * dhd_idx2net(void *pub, int ifidx);
 extern int net_os_send_hang_message(struct net_device *dev);
-extern int wl_host_event(dhd_pub_t *dhd_pub, int *idx, void *pktdata,
+extern int wl_host_event(dhd_pub_t *dhd_pub, int *idx, void *pktdata, size_t pktlen,
                          wl_event_msg_t *, void **data_ptr);
 extern void wl_event_to_host_order(wl_event_msg_t * evt);
 
diff --git a/drivers/net/wireless/bcmdhd/dhd_common.c b/drivers/net/wireless/bcmdhd/dhd_common.c
index 31ccb49c64c..7ca98c908c7 100644
--- a/drivers/net/wireless/bcmdhd/dhd_common.c
+++ b/drivers/net/wireless/bcmdhd/dhd_common.c
@@ -1184,7 +1184,7 @@ wl_show_host_event(wl_event_msg_t *event, void *event_data)
 #endif /* SHOW_EVENTS */
 
 int
-wl_host_event(dhd_pub_t *dhd_pub, int *ifidx, void *pktdata,
+wl_host_event(dhd_pub_t *dhd_pub, int *ifidx, void *pktdata, size_t pktlen,
               wl_event_msg_t *event, void **data_ptr)
 {
 	/* check whether packet is a BRCM event pkt */
@@ -1205,6 +1205,9 @@ wl_host_event(dhd_pub_t *dhd_pub, int *ifidx, void *pktdata,
 		return (BCME_ERROR);
 	}
 
+	if (pktlen < sizeof(bcm_event_t))
+		return (BCME_ERROR);
+
 	*data_ptr = &pvt_data[1];
 	event_data = *data_ptr;
 
@@ -1214,8 +1217,15 @@ wl_host_event(dhd_pub_t *dhd_pub, int *ifidx, void *pktdata,
 	type = ntoh32_ua((void *)&event->event_type);
 	flags = ntoh16_ua((void *)&event->flags);
 	status = ntoh32_ua((void *)&event->status);
+
 	datalen = ntoh32_ua((void *)&event->datalen);
+	if (datalen > pktlen)
+		return (BCME_ERROR);
+
 	evlen = datalen + sizeof(bcm_event_t);
+	if (evlen > pktlen) {
+		return (BCME_ERROR);
+	}
 
 	switch (type) {
 #ifdef DHD_DEBUG
diff --git a/drivers/net/wireless/bcmdhd/dhd_linux.c b/drivers/net/wireless/bcmdhd/dhd_linux.c
index 26c37103ac7..13f0c3455d7 100644
--- a/drivers/net/wireless/bcmdhd/dhd_linux.c
+++ b/drivers/net/wireless/bcmdhd/dhd_linux.c
@@ -627,7 +627,7 @@ static int dhd_toe_get(dhd_info_t *dhd, int idx, uint32 *toe_ol);
 static int dhd_toe_set(dhd_info_t *dhd, int idx, uint32 toe_ol);
 #endif /* TOE */
 
-static int dhd_wl_host_event(dhd_info_t *dhd, int *ifidx, void *pktdata,
+static int dhd_wl_host_event(dhd_info_t *dhd, int *ifidx, void *pktdata, size_t pktlen,
                              wl_event_msg_t *event_ptr, void **data_ptr);
 #if defined(SUPPORT_P2P_GO_PS)
 #ifdef PROP_TXSTATUS
@@ -2046,6 +2046,7 @@ dhd_rx_frame(dhd_pub_t *dhdp, int ifidx, void *pktbuf, int numpkt, uint8 chan)
 #else
 			skb->mac.raw,
 #endif /* LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 22) */
+			len - 2,
 			&event,
 			&data);
 
@@ -5851,13 +5852,13 @@ dhd_get_wireless_stats(struct net_device *dev)
 #endif /* defined(WL_WIRELESS_EXT) */
 
 static int
-dhd_wl_host_event(dhd_info_t *dhd, int *ifidx, void *pktdata,
+dhd_wl_host_event(dhd_info_t *dhd, int *ifidx, void *pktdata, size_t pktlen,
 	wl_event_msg_t *event, void **data)
 {
 	int bcmerror = 0;
 	ASSERT(dhd != NULL);
 
-	bcmerror = wl_host_event(&dhd->pub, ifidx, pktdata, event, data);
+	bcmerror = wl_host_event(&dhd->pub, ifidx, pktdata, pktlen, event, data);
 	if (bcmerror != BCME_OK)
 		return (bcmerror);