Patch "brcmfmac: fix possible buffer overflow in brcmf_cfg80211_mgmt_tx()" has been added to the 4.12-stable tree

This is a note to let you know that I've just added the patch titled

brcmfmac: fix possible buffer overflow in brcmf_cfg80211_mgmt_tx()

to the 4.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
brcmfmac-fix-possible-buffer-overflow-in-brcmf_cfg80211_mgmt_tx.patch
and it can be found in the queue-4.12 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Arend van Spriel <[email protected]>
Date: Fri, 7 Jul 2017 21:09:06 +0100
Subject: brcmfmac: fix possible buffer overflow in brcmf_cfg80211_mgmt_tx()

From: Arend van Spriel <[email protected]>

[ Upstream commit 8f44c9a41386729fea410e688959ddaa9d51be7c ]

The lower level nl80211 code in cfg80211 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. However, 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));

---
 drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c |    5 +++++
 1 file changed, 5 insertions(+)

@@ -4851,6 +4851,11 @@ brcmf_cfg80211_mgmt_tx(struct wiphy *wip
 		cfg80211_mgmt_tx_status(wdev, *cookie, buf, len, true,
 					GFP_KERNEL);
 	} else if (ieee80211_is_action(mgmt->frame_control)) {
+		if (len > BRCMF_FIL_ACTION_FRAME_SIZE + DOT11_MGMT_HDR_LEN) {
+			brcmf_err("invalid action frame length\n");
+			err = -EINVAL;
+			goto exit;
+		}
 		af_params = kzalloc(sizeof(*af_params), GFP_KERNEL);
 		if (af_params == NULL) {
 			brcmf_err("unable to allocate frame\n");

Patches currently in stable-queue which might be from [email protected] are

queue-4.12/brcmfmac-fix-possible-buffer-overflow-in-brcmf_cfg80211_mgmt_tx.patch