[PATCH v3 6/6] wifi: mwifiex: fix OOB read from inflated TLV length in IBSS peer event

[Tristan Madani <tristmd@gmail.com>]

From: Tristan Madani <tristan@talencesecurity.com>

The IBSS connected handler replaces the buffer-bounded evt_len with
the firmware-controlled TLV header length. An inflated value drives the
IE parsing loop past the event buffer into adjacent kernel heap memory.

Cap the TLV-derived length at the remaining event data size.

Fixes: 432da7d243da ("mwifiex: add HT aggregation support for adhoc mode")
Signed-off-by: Tristan Madani <tristan@talencesecurity.com>
---
Changes in v3:
  - Regenerated from wireless-next with proper git format-patch to
    produce valid index hashes (v2 had post-processed index lines).

Changes in v2:
  - No code changes from v1.

 drivers/net/wireless/marvell/mwifiex/sta_event.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/wireless/marvell/mwifiex/sta_event.c b/drivers/net/wireless/marvell/mwifiex/sta_event.c
index 6b7e5b6a66a9e..62a879c09106e 100644
--- a/drivers/net/wireless/marvell/mwifiex/sta_event.c
+++ b/drivers/net/wireless/marvell/mwifiex/sta_event.c
@@ -45,6 +45,10 @@ static int mwifiex_check_ibss_peer_capabilities(struct mwifiex_private *priv,
 		 */
 		evt_len = le16_to_cpu(tlv_mgmt_frame->header.len);
 		curr += (sizeof(*tlv_mgmt_frame) + 12);
+		if (evt_len > event->len -
+		    (curr - event->data))
+			evt_len = event->len -
+				  (curr - event->data);
 	} else {
 		mwifiex_dbg(priv->adapter, MSG,
 			    "management frame tlv not found!\n");
-- 
2.47.3