[PATCH 3.16 080/204] brcmfmac: Add check for short event packets

[Ben Hutchings]

3.16.52-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Kevin Cernekee <cernekee@xxxxxxxxxxxx>

commit dd2349121bb1b8ff688c3ca6a2a0bea9d8c142ca upstream.

The length of the data in the received skb is currently passed into
brcmf_fweh_process_event() as packet_len, but this value is not checked.
event_packet should be followed by DATALEN bytes of additional event
data.  Ensure that the received packet actually contains at least
DATALEN bytes of additional data, to avoid copying uninitialized memory
into event->data.

Suggested-by: Mattias Nissler <mnissler@xxxxxxxxxxxx>
Signed-off-by: Kevin Cernekee <cernekee@xxxxxxxxxxxx>
Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxxxxxx>
[bwh: Backported to 3.16: adjust filename]
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
 drivers/net/wireless/brcm80211/brcmfmac/fweh.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/net/wireless/brcm80211/brcmfmac/fweh.c
+++ b/drivers/net/wireless/brcm80211/brcmfmac/fweh.c
@@ -406,7 +406,8 @@ void brcmf_fweh_process_event(struct brc
 	if (code != BRCMF_E_IF && !fweh->evt_handler[code])
 		return;
 
-	if (datalen > BRCMF_DCMD_MAXLEN)
+	if (datalen > BRCMF_DCMD_MAXLEN ||
+	    datalen + sizeof(*event_packet) > packet_len)
 		return;
 
 	if (in_interrupt())