From patchwork Mon May 31 20:28:29 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Johannes Berg X-Patchwork-Id: 450706 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0A9A0C47080 for ; Mon, 31 May 2021 20:29:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E46D161159 for ; Mon, 31 May 2021 20:29:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232244AbhEaUam (ORCPT ); Mon, 31 May 2021 16:30:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38404 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232131AbhEaUaV (ORCPT ); Mon, 31 May 2021 16:30:21 -0400 Received: from sipsolutions.net (s3.sipsolutions.net [IPv6:2a01:4f8:191:4433::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AEA54C061763; Mon, 31 May 2021 13:28:41 -0700 (PDT) Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.94.2) (envelope-from ) id 1lnoWd-000F0y-Nt; Mon, 31 May 2021 22:28:39 +0200 From: Johannes Berg To: linux-wireless@vger.kernel.org Cc: stable@vger.kernel.org, Johannes Berg Subject: [PATCH v4.4 05/10] mac80211: drop A-MSDUs on old ciphers Date: Mon, 31 May 2021 22:28:29 +0200 Message-Id: <20210531202834.179810-6-johannes@sipsolutions.net> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210531202834.179810-1-johannes@sipsolutions.net> References: <20210531202834.179810-1-johannes@sipsolutions.net> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org From: Johannes Berg commit 270032a2a9c4535799736142e1e7c413ca7b836e upstream. With old ciphers (WEP and TKIP) we shouldn't be using A-MSDUs since A-MSDUs are only supported if we know that they are, and the only practical way for that is HT support which doesn't support old ciphers. However, we would normally accept them anyway. Since we check the MMIC before deaggregating A-MSDUs, and the A-MSDU bit in the QoS header is not protected in TKIP (or WEP), this enables attacks similar to CVE-2020-24588. To prevent that, drop A-MSDUs completely with old ciphers. Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20210511200110.076543300172.I548e6e71f1ee9cad4b9a37bf212ae7db723587aa@changeid Signed-off-by: Johannes Berg --- net/mac80211/rx.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index 85d7ac83d847..23c1e6529900 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -2264,6 +2264,23 @@ ieee80211_rx_h_amsdu(struct ieee80211_rx_data *rx) if (skb_linearize(skb)) return RX_DROP_UNUSABLE; + if (rx->key) { + /* + * We should not receive A-MSDUs on pre-HT connections, + * and HT connections cannot use old ciphers. Thus drop + * them, as in those cases we couldn't even have SPP + * A-MSDUs or such. + */ + switch (rx->key->conf.cipher) { + case WLAN_CIPHER_SUITE_WEP40: + case WLAN_CIPHER_SUITE_WEP104: + case WLAN_CIPHER_SUITE_TKIP: + return RX_DROP_UNUSABLE; + default: + break; + } + } + ieee80211_amsdu_to_8023s(skb, &frame_list, dev->dev_addr, rx->sdata->vif.type, rx->local->hw.extra_tx_headroom, true);