[PATCH] brcmfmac: buffer overflow in brcmf_cfg80211_mgmt_tx()

[Dan Carpenter <dan.carpenter@xxxxxxxxxx>]

The lower level networking code ensures that "len" is between 25 and
NL80211_ATTR_FRAME (2304).  We subtract DOT11_MGMT_HDR_LEN (24) from
"len" so thats's max of 2280.  But the action_frame->data[] buffer is
only BRCMF_FIL_ACTION_FRAME_SIZE (1800) bytes long so this memcpy() can
overflow.

	memcpy(action_frame->data, &buf[DOT11_MGMT_HDR_LEN],
	       le16_to_cpu(action_frame->len));

Reported-by: "freenerguo(郭大兴)" <freenerguo@xxxxxxxxxxx>
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
index dcde596c9eb9..bdae7b44a5ec 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c
@@ -4934,6 +4934,11 @@ brcmf_cfg80211_mgmt_tx(struct wiphy *wiphy, struct wireless_dev *wdev,
 		cfg80211_mgmt_tx_status(wdev, *cookie, buf, len, true,
 					GFP_KERNEL);
 	} else if (ieee80211_is_action(mgmt->frame_control)) {
+		if (len > sizeof(action_frame->data) + DOT11_MGMT_HDR_LEN) {
+			err = -EINVAL;
+			goto exit;
+		}
+
 		af_params = kzalloc(sizeof(*af_params), GFP_KERNEL);
 		if (af_params == NULL) {
 			brcmf_err("unable to allocate frame\n");