Return-path: Received: from mail-gw3-out.broadcom.com ([216.31.210.64]:35905 "EHLO mail-gw3-out.broadcom.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932286AbcIEJqD (ORCPT ); Mon, 5 Sep 2016 05:46:03 -0400 From: Arend van Spriel To: Kalle Valo Cc: linux-wireless , Arend van Spriel Subject: [PATCH] brcmfmac: avoid potential stack overflow in brcmf_cfg80211_start_ap() Date: Mon, 5 Sep 2016 10:45:47 +0100 Message-Id: <1473068749-22487-1-git-send-email-arend.vanspriel@broadcom.com> (sfid-20160905_114618_437823_91752636) Sender: linux-wireless-owner@vger.kernel.org List-ID: 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. Cc: stable@vger.kernel.org # v4.7 Reported-by: Daxing Guo Reviewed-by: Hante Meuleman Reviewed-by: Pieter-Paul Giesberts Reviewed-by: Franky Lin Signed-off-by: Arend van Spriel --- drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c index 5db56a7..b8aec5e5 100644 --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c @@ -4527,7 +4527,7 @@ brcmf_cfg80211_start_ap(struct wiphy *wiphy, struct net_device *ndev, (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); -- 1.9.1