From nobody Tue Dec 16 12:34:02 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1566FC4332F for ; Thu, 13 Oct 2022 17:54:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230029AbiJMRyz (ORCPT ); Thu, 13 Oct 2022 13:54:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54500 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229957AbiJMRyO (ORCPT ); Thu, 13 Oct 2022 13:54:14 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8B9511578A7; Thu, 13 Oct 2022 10:53:43 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 4BB0F618F4; Thu, 13 Oct 2022 17:53:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5A779C433C1; Thu, 13 Oct 2022 17:53:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1665683621; bh=dJKQV479mGlFMVR1hzi8I2tjgh9+4htqItrDF5VQ4ek=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=v2+3Zs1IkmC1nJT4fgWWe9u1oeoahODz34pUpCO0c6yqVHhdr2I0+LS2WwraeaQfD OyN2fJWu398ydWVLFc5Me9cE264SGl/DX1znOyHXHn7n3hs1Vyiea2el5g1kOVGYhA SLCacRSOBqgEn5doFm3ZnMQqmwN+pGFnNxOCop7Q= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Kees Cook , Johannes Berg Subject: [PATCH 5.4 31/38] wifi: cfg80211/mac80211: reject bad MBSSID elements Date: Thu, 13 Oct 2022 19:52:32 +0200 Message-Id: <20221013175145.279415764@linuxfoundation.org> X-Mailer: git-send-email 2.38.0 In-Reply-To: <20221013175144.245431424@linuxfoundation.org> References: <20221013175144.245431424@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Johannes Berg commit 8f033d2becc24aa6bfd2a5c104407963560caabc upstream. Per spec, the maximum value for the MaxBSSID ('n') indicator is 8, and the minimum is 1 since a multiple BSSID set with just one BSSID doesn't make sense (the # of BSSIDs is limited by 2^n). Limit this in the parsing in both cfg80211 and mac80211, rejecting any elements with an invalid value. This fixes potentially bad shifts in the processing of these inside the cfg80211_gen_new_bssid() function later. I found this during the investigation of CVE-2022-41674 fixed by the previous patch. Fixes: 0b8fb8235be8 ("cfg80211: Parsing of Multiple BSSID information in sc= anning") Fixes: 78ac51f81532 ("mac80211: support multi-bssid") Reviewed-by: Kees Cook Signed-off-by: Johannes Berg Signed-off-by: Greg Kroah-Hartman --- net/mac80211/util.c | 2 ++ net/wireless/scan.c | 2 ++ 2 files changed, 4 insertions(+) --- a/net/mac80211/util.c +++ b/net/mac80211/util.c @@ -1289,6 +1289,8 @@ static size_t ieee802_11_find_bssid_prof for_each_element_id(elem, WLAN_EID_MULTIPLE_BSSID, start, len) { if (elem->datalen < 2) continue; + if (elem->data[0] < 1 || elem->data[0] > 8) + continue; =20 for_each_element(sub, elem->data + 1, elem->datalen - 1) { u8 new_bssid[ETH_ALEN]; --- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -1582,6 +1582,8 @@ static void cfg80211_parse_mbssid_data(s for_each_element_id(elem, WLAN_EID_MULTIPLE_BSSID, ie, ielen) { if (elem->datalen < 4) continue; + if (elem->data[0] < 1 || (int)elem->data[0] > 8) + continue; for_each_element(sub, elem->data + 1, elem->datalen - 1) { u8 profile_len;