From mboxrd@z Thu Jan 1 00:00:00 1970 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 B66EAC433FE for ; Thu, 13 Oct 2022 18:34:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231974AbiJMSd6 (ORCPT ); Thu, 13 Oct 2022 14:33:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44122 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229649AbiJMSdV (ORCPT ); Thu, 13 Oct 2022 14:33:21 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9CBA517FD5F; Thu, 13 Oct 2022 11:29:21 -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 A026761A51; Thu, 13 Oct 2022 18:01:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AFEA8C433D7; Thu, 13 Oct 2022 18:01:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1665684096; bh=Ajm14oqIOS8bNZ+O27M/3u4Vz08BqrePq7KdTFY7v80=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Hy2H85DMOI2HJ2ZZn20GJS61mnFdnhcLrmxKapiO0JL5uVO8wO+v8VfXBBKYmgUh9 HByX3njDxrMwhaCjbGnhbJ+RgOLOOz9KzXw14wI+IBf8fWkASFdoG2KJwi1vR0o+GM WTaHk6mMU3/Ew4ExqI12h3cHrV2VLJIyjAM0bUYc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ilan Peer , Kees Cook , Johannes Berg Subject: [PATCH 6.0 23/34] wifi: mac80211: fix MBSSID parsing use-after-free Date: Thu, 13 Oct 2022 19:53:01 +0200 Message-Id: <20221013175147.118965481@linuxfoundation.org> X-Mailer: git-send-email 2.38.0 In-Reply-To: <20221013175146.507746257@linuxfoundation.org> References: <20221013175146.507746257@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Johannes Berg commit ff05d4b45dd89b922578dac497dcabf57cf771c6 upstream. When we parse a multi-BSSID element, we might point some element pointers into the allocated nontransmitted_profile. However, we free this before returning, causing UAF when the relevant pointers in the parsed elements are accessed. Fix this by not allocating the scratch buffer separately but as part of the returned structure instead, that way, there are no lifetime issues with it. The scratch buffer introduction as part of the returned data here is taken from MLO feature work done by Ilan. This fixes CVE-2022-42719. Fixes: 5023b14cf4df ("mac80211: support profile split between elements") Co-developed-by: Ilan Peer Signed-off-by: Ilan Peer Reviewed-by: Kees Cook Signed-off-by: Johannes Berg Signed-off-by: Greg Kroah-Hartman --- net/mac80211/ieee80211_i.h | 8 ++++++++ net/mac80211/util.c | 28 ++++++++++++++-------------- 2 files changed, 22 insertions(+), 14 deletions(-) --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -1704,6 +1704,14 @@ struct ieee802_11_elems { /* whether a parse error occurred while retrieving these elements */ bool parse_error; + + /* + * scratch buffer that can be used for various element parsing related + * tasks, e.g., element de-fragmentation etc. + */ + size_t scratch_len; + u8 *scratch_pos; + u8 scratch[]; }; static inline struct ieee80211_local *hw_to_local( --- a/net/mac80211/util.c +++ b/net/mac80211/util.c @@ -1503,24 +1503,26 @@ ieee802_11_parse_elems_full(struct ieee8 const struct element *non_inherit = NULL; u8 *nontransmitted_profile; int nontransmitted_profile_len = 0; + size_t scratch_len = params->len; - elems = kzalloc(sizeof(*elems), GFP_ATOMIC); + elems = kzalloc(sizeof(*elems) + scratch_len, GFP_ATOMIC); if (!elems) return NULL; elems->ie_start = params->start; elems->total_len = params->len; + elems->scratch_len = scratch_len; + elems->scratch_pos = elems->scratch; - nontransmitted_profile = kmalloc(params->len, GFP_ATOMIC); - if (nontransmitted_profile) { - nontransmitted_profile_len = - ieee802_11_find_bssid_profile(params->start, params->len, - elems, params->bss, - nontransmitted_profile); - non_inherit = - cfg80211_find_ext_elem(WLAN_EID_EXT_NON_INHERITANCE, - nontransmitted_profile, - nontransmitted_profile_len); - } + nontransmitted_profile = elems->scratch_pos; + nontransmitted_profile_len = + ieee802_11_find_bssid_profile(params->start, params->len, + elems, params->bss, + nontransmitted_profile); + elems->scratch_pos += nontransmitted_profile_len; + elems->scratch_len -= nontransmitted_profile_len; + non_inherit = cfg80211_find_ext_elem(WLAN_EID_EXT_NON_INHERITANCE, + nontransmitted_profile, + nontransmitted_profile_len); elems->crc = _ieee802_11_parse_elems_full(params, elems, non_inherit); @@ -1554,8 +1556,6 @@ ieee802_11_parse_elems_full(struct ieee8 offsetofend(struct ieee80211_bssid_index, dtim_count)) elems->dtim_count = elems->bssid_index->dtim_count; - kfree(nontransmitted_profile); - return elems; }