From patchwork Fri Oct 14 16:47:05 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Johannes Berg X-Patchwork-Id: 13007213 X-Patchwork-Delegate: johannes@sipsolutions.net 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 2CAA3C43219 for ; Fri, 14 Oct 2022 16:48:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230071AbiJNQsV (ORCPT ); Fri, 14 Oct 2022 12:48:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38072 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229994AbiJNQsL (ORCPT ); Fri, 14 Oct 2022 12:48:11 -0400 Received: from sipsolutions.net (s3.sipsolutions.net [IPv6:2a01:4f8:191:4433::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1AC411C97D6; Fri, 14 Oct 2022 09:48:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sipsolutions.net; s=mail; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Content-Type:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-To: Resent-Cc:Resent-Message-ID; bh=GECKQhOYk4SRCHi7X/tcBe1wmEDBMxeEoS0zQhgrTvk=; t=1665766088; x=1666975688; b=hrBD6fgmVf6NZfX1gngYAVN1DJf2kWQXR/mB28ecHn86vsF QbtzeAwFbMEofH0i/vsRbTiF/0x5nLNOvQaTHAXXLzSQGTqNT0AIn4Ys1n0yFgJ4I24oqEImc8x9n Kb2O1OXjMHUwMPGLx4B0qDX+HsRphpD4vAn7pHGr0vIhcxPkP+Hm2JGQVuID+vIp7OTM+ojkN2NAV MXUaj9i5j2qnxXzvpI2jVxG1Rrbton37c9l7YTm+mVKmwAD4KxBHlSX+8H8AVNVCeXgWQcyT9oatK CJL1VedbHvzX7fTKZZJW6MDc9n2T1IcyxTner6EOLr2cX+hIN6BepCHrP8TkbGSg==; Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.96) (envelope-from ) id 1ojNqr-006gzN-0U; Fri, 14 Oct 2022 18:48:03 +0200 From: Johannes Berg To: linux-wireless@vger.kernel.org, stable@vger.kernel.org Cc: Felix Fietkau , Thadeu Lima de Souza Cascardo , Marcus Meissner , Jiri Kosina , Steve deRosier , Johannes Berg , Ilan Peer , Kees Cook Subject: [RFC v5.4 3/3] wifi: mac80211: fix MBSSID parsing use-after-free Date: Fri, 14 Oct 2022 18:47:05 +0200 Message-Id: <20221014184650.0065abf86cc0.I4691a91b83e1325524f786a638e853ccb49c2443@changeid> X-Mailer: git-send-email 2.37.3 In-Reply-To: <20221014164705.31486-1-johannes@sipsolutions.net> References: <20221014164705.31486-1-johannes@sipsolutions.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org From: Johannes Berg Commit ff05d4b45dd89b922578dac497dcabf57cf771c6 upstream. This is a different version of the commit, changed to store the non-transmitted profile in the elems, and freeing it in the few places where it's relevant, since that is only the case when the last argument for parsing (the non-tx BSSID) is non-NULL. 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 --- net/mac80211/ieee80211_i.h | 2 ++ net/mac80211/mlme.c | 6 +++++- net/mac80211/scan.c | 2 ++ net/mac80211/util.c | 7 ++++++- 4 files changed, 15 insertions(+), 2 deletions(-) diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index 3d5da7a97be4..f30a205323de 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -1519,6 +1519,8 @@ struct ieee802_11_elems { u8 country_elem_len; u8 bssid_index_len; + void *nontx_profile; + /* whether a parse error occurred while retrieving these elements */ bool parse_error; }; diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c index 7d116aa4ea1f..b48a09043663 100644 --- a/net/mac80211/mlme.c +++ b/net/mac80211/mlme.c @@ -3299,6 +3299,7 @@ static bool ieee80211_assoc_success(struct ieee80211_sub_if_data *sdata, sdata_info(sdata, "AP bug: VHT operation missing from AssocResp\n"); } + kfree(bss_elems.nontx_profile); } /* @@ -3883,6 +3884,7 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata, ifmgd->assoc_data->timeout = jiffies; ifmgd->assoc_data->timeout_started = true; run_again(sdata, ifmgd->assoc_data->timeout); + kfree(elems.nontx_profile); return; } @@ -4050,7 +4052,7 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata, ieee80211_report_disconnect(sdata, deauth_buf, sizeof(deauth_buf), true, WLAN_REASON_DEAUTH_LEAVING); - return; + goto free; } if (sta && elems.opmode_notif) @@ -4065,6 +4067,8 @@ static void ieee80211_rx_mgmt_beacon(struct ieee80211_sub_if_data *sdata, elems.cisco_dtpc_elem); ieee80211_bss_info_change_notify(sdata, changed); +free: + kfree(elems.nontx_profile); } void ieee80211_sta_rx_queued_mgmt(struct ieee80211_sub_if_data *sdata, diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c index c353162e81ae..ee65f1f50a0a 100644 --- a/net/mac80211/scan.c +++ b/net/mac80211/scan.c @@ -216,6 +216,8 @@ ieee80211_bss_info_update(struct ieee80211_local *local, rx_status, beacon); } + kfree(elems.nontx_profile); + return bss; } diff --git a/net/mac80211/util.c b/net/mac80211/util.c index 1ba37f67a2a0..6223af1c3457 100644 --- a/net/mac80211/util.c +++ b/net/mac80211/util.c @@ -1363,6 +1363,11 @@ u32 ieee802_11_parse_elems_crc(const u8 *start, size_t len, bool action, cfg80211_find_ext_elem(WLAN_EID_EXT_NON_INHERITANCE, nontransmitted_profile, nontransmitted_profile_len); + if (!nontransmitted_profile_len) { + nontransmitted_profile_len = 0; + kfree(nontransmitted_profile); + nontransmitted_profile = NULL; + } } crc = _ieee802_11_parse_elems_crc(start, len, action, elems, filter, @@ -1392,7 +1397,7 @@ u32 ieee802_11_parse_elems_crc(const u8 *start, size_t len, bool action, offsetofend(struct ieee80211_bssid_index, dtim_count)) elems->dtim_count = elems->bssid_index->dtim_count; - kfree(nontransmitted_profile); + elems->nontx_profile = nontransmitted_profile; return crc; }