Patch "brcmfmac: avoid potential stack overflow in brcmf_cfg80211_start_ap()" has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

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

    brcmfmac: avoid potential stack overflow in brcmf_cfg80211_start_ap()

to the 4.4-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-avoid-potential-stack-overflow-in-brcmf_cfg80211_start_ap.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From ded89912156b1a47d940a0c954c43afbabd0c42c Mon Sep 17 00:00:00 2001
From: Arend Van Spriel <arend.vanspriel@broadcom.com>
Date: Mon, 5 Sep 2016 10:45:47 +0100
Subject: brcmfmac: avoid potential stack overflow in brcmf_cfg80211_start_ap()

From: Arend Van Spriel <arend.vanspriel@broadcom.com>

commit ded89912156b1a47d940a0c954c43afbabd0c42c upstream.

User-space can choose to omit NL80211_ATTR_SSID and only provide raw
IE TLV data. When doing so it can provide SSID IE with length exceeding
the allowed size. The driver further processes this IE copying it
into a local variable without checking the length. Hence stack can be
corrupted and used as exploit.

Reported-by: Daxing Guo <freener.gdx@gmail.com>
Reviewed-by: Hante Meuleman <hante.meuleman@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com>
Reviewed-by: Franky Lin <franky.lin@broadcom.com>
Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Juerg Haefliger <juerg.haefliger@hpe.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/net/wireless/brcm80211/brcmfmac/cfg80211.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/wireless/brcm80211/brcmfmac/cfg80211.c
+++ b/drivers/net/wireless/brcm80211/brcmfmac/cfg80211.c
@@ -4102,7 +4102,7 @@ brcmf_cfg80211_start_ap(struct wiphy *wi
 				(u8 *)&settings->beacon.head[ie_offset],
 				settings->beacon.head_len - ie_offset,
 				WLAN_EID_SSID);
-		if (!ssid_ie)
+		if (!ssid_ie || ssid_ie->len > IEEE80211_MAX_SSID_LEN)
 			return -EINVAL;
 
 		memcpy(ssid_le.SSID, ssid_ie->data, ssid_ie->len);


Patches currently in stable-queue which might be from arend.vanspriel@broadcom.com are

queue-4.4/brcmfmac-avoid-potential-stack-overflow-in-brcmf_cfg80211_start_ap.patch