From nobody Tue Mar 15 18:16:33 2022 X-Original-To: dev-commits-src-all@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id F3B961A258EE; Tue, 15 Mar 2022 18:16:33 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4KJ1nY31vZz58wn; Tue, 15 Mar 2022 18:16:33 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1647368193; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=7x5fcXQL+DIrls0NLnkNJgP1neOy5L8q6/jKa8WrwUI=; b=hxFTZ+Bp6UDBiV8JEbRSKMmjSZTnP95Jl1ImRMEWPWTBflU1KimxYkIttU8eL2GjnKcpJJ QAoJKTmDE1Wd0bFa76+zYtmAWT/WTT31THVfSZ7ggzcyJQPr44qD3D2Y22TAZAkfbyfFho ktcHo+2ag8w26CLg51M1KQ1e98t8qwVhVXhWaoUCGMTJ7cfPuaoyZxYx2od2fL14H9IA7B ONfkFpUlQmYcq951ZeTUjz0GTqHfAYhPNliS9iFH5PR3vs50DJeTeHj0nZQYPTu0IIESHV +gKfJQPkL+tc33y8AIm8ad/3UGiC+oxxv+wBRcHjXVo1Tx4h5IF5YOwiTnkYYQ== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by mxrelay.nyi.freebsd.org (Postfix) with ESMTPS id 3F76426C05; Tue, 15 Mar 2022 18:16:33 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from gitrepo.freebsd.org ([127.0.1.44]) by gitrepo.freebsd.org (8.16.1/8.16.1) with ESMTP id 22FIGXuN075937; Tue, 15 Mar 2022 18:16:33 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 22FIGXuS075936; Tue, 15 Mar 2022 18:16:33 GMT (envelope-from git) Date: Tue, 15 Mar 2022 18:16:33 GMT Message-Id: <202203151816.22FIGXuS075936@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Mark Johnston Subject: git: ae6d654f4fa1 - releng/12.2 - net80211: mitigation against A-MSDU design flaw List-Id: Commit messages for all branches of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-all List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-dev-commits-src-all@freebsd.org X-BeenThere: dev-commits-src-all@freebsd.org MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: markj X-Git-Repository: src X-Git-Refname: refs/heads/releng/12.2 X-Git-Reftype: branch X-Git-Commit: ae6d654f4fa167f473a40417479e607029670679 Auto-Submitted: auto-generated ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1647368193; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=7x5fcXQL+DIrls0NLnkNJgP1neOy5L8q6/jKa8WrwUI=; b=sMlFLWpIGCG0jMnNp0WhmNOwhHtDHTFSMgytB8ANusq4fOtd54PvzjzlxZfkxlB8Dew/k1 4KljFRZz1f9OrNbHmjEWPLoLBJ9xxNzYra+ssCGgenCHOzmfgXMmUALyPkq006PlYhxPgz fcxA6PaDBekmR3JNaokXrn2aGL6Lk4aiRvzArzQmCTI/8tihMutHbQ5YW8dj9xtMIFu6p9 xDuZ27uF82TtAndr8kJcwyx7qu/2Uas3YM3/2m78hp8gOEFF9ix/DWCygkt4RHBfuepNEc 6/CP1jCl0K0Xbn5dCJFNnzyzZps1qLADbLimhEqVYc/z+NrVMvOtyT8tq1Ipbw== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1647368193; a=rsa-sha256; cv=none; b=l52v4TTzVGU37aUBh6XcU0QBch0m4ijrqHwIBa2OpoHY0EpmhHQHYc0Oo/jKueaoYjpRt4 PTSM6ldNgfUN+ftazo3a5eyU8eqfQgsieM6TozqyrjtbCNy2G4UBVOrqUNm13wK1exfJQs jEaipIlyPUpyIxlRb/wpt8VpnVvLVE0TW6kOWY+qX5Y4m9HKYsEIynDHzKKCSCe7Aw+SS7 ZsVJiAMpI5Lp3tK1DsUk6SoCCP2F/sS3swCquePIQF/bHIt9dAsAjq96H/C6U447d6nyfq zp3NN9FIy3m6OHc8yJYT1g7XANlPqL+CDnVIW//mWEPjix5qaN2egUP8HEWdXQ== ARC-Authentication-Results: i=1; mx1.freebsd.org; none X-ThisMailContainsUnwantedMimeParts: N The branch releng/12.2 has been updated by markj: URL: https://cgit.FreeBSD.org/src/commit/?id=ae6d654f4fa167f473a40417479e607029670679 commit ae6d654f4fa167f473a40417479e607029670679 Author: Mathy Vanhoef AuthorDate: 2021-06-06 22:10:52 +0000 Commit: Mark Johnston CommitDate: 2022-03-15 17:39:02 +0000 net80211: mitigation against A-MSDU design flaw Mitigate A-MSDU injection attacks by detecting if the destination address of a subframe equals an RFC1042 (i.e., LLC/SNAP) header, and if so dropping the complete A-MSDU frame. This mitigates known attacks, although new (unknown) aggregation-based attacks may remain possible. This defense works because in A-MSDU aggregation injection attacks, a normal encrypted Wi-Fi frame is turned into an A-MSDU frame. This means the first 6 bytes of the first A-MSDU subframe correspond to an RFC1042 header. In other words, the destination MAC address of the first A-MSDU subframe contains the start of an RFC1042 header during an aggregation attack. We can detect this and thereby prevent this specific attack. This relates to section 7.2 in the 2021 Usenix "FragAttacks" (Fragment and Forge: Breaking Wi-Fi Through Frame Aggregation and Fragmentation) paper. Submitted by: Mathy Vanhoef (Mathy.Vanhoef kuleuven.be) Security: CVE-2020-24588 PR: 256119 (cherry picked from commit f024bdf1155f36d2d8c4caa533b66e4040c4c469) (cherry picked from commit 41ca1d50a8657959df2009daa300dda56a090d5e) (cherry picked from commit 76ee776f4d9f146f7a97ac9bab388c51a1c787c9) Approved by: so Security: FreeBSD-SA-22:02.wifi --- sys/net80211/ieee80211_adhoc.c | 2 +- sys/net80211/ieee80211_hostap.c | 2 +- sys/net80211/ieee80211_input.c | 20 ++++++++++++++++++-- sys/net80211/ieee80211_input.h | 3 ++- sys/net80211/ieee80211_sta.c | 2 +- sys/net80211/ieee80211_wds.c | 2 +- 6 files changed, 24 insertions(+), 7 deletions(-) diff --git a/sys/net80211/ieee80211_adhoc.c b/sys/net80211/ieee80211_adhoc.c index ea1519b3381d..c97b99425caa 100644 --- a/sys/net80211/ieee80211_adhoc.c +++ b/sys/net80211/ieee80211_adhoc.c @@ -558,7 +558,7 @@ adhoc_input(struct ieee80211_node *ni, struct mbuf *m, /* * Finally, strip the 802.11 header. */ - m = ieee80211_decap(vap, m, hdrspace); + m = ieee80211_decap(vap, m, hdrspace, qos); if (m == NULL) { /* XXX mask bit to check for both */ /* don't count Null data frames as errors */ diff --git a/sys/net80211/ieee80211_hostap.c b/sys/net80211/ieee80211_hostap.c index 6687276d0181..8c132332f86b 100644 --- a/sys/net80211/ieee80211_hostap.c +++ b/sys/net80211/ieee80211_hostap.c @@ -744,7 +744,7 @@ hostap_input(struct ieee80211_node *ni, struct mbuf *m, /* * Finally, strip the 802.11 header. */ - m = ieee80211_decap(vap, m, hdrspace); + m = ieee80211_decap(vap, m, hdrspace, qos); if (m == NULL) { /* XXX mask bit to check for both */ /* don't count Null data frames as errors */ diff --git a/sys/net80211/ieee80211_input.c b/sys/net80211/ieee80211_input.c index 404eaf96716a..979e9aef9d12 100644 --- a/sys/net80211/ieee80211_input.c +++ b/sys/net80211/ieee80211_input.c @@ -294,7 +294,8 @@ ieee80211_deliver_data(struct ieee80211vap *vap, } struct mbuf * -ieee80211_decap(struct ieee80211vap *vap, struct mbuf *m, int hdrlen) +ieee80211_decap(struct ieee80211vap *vap, struct mbuf *m, int hdrlen, + uint8_t qos) { struct ieee80211_qosframe_addr4 wh; struct ether_header *eh; @@ -316,7 +317,9 @@ ieee80211_decap(struct ieee80211vap *vap, struct mbuf *m, int hdrlen) llc->llc_snap.org_code[1] == 0 && llc->llc_snap.org_code[2] == 0 && /* NB: preserve AppleTalk frames that have a native SNAP hdr */ !(llc->llc_snap.ether_type == htons(ETHERTYPE_AARP) || - llc->llc_snap.ether_type == htons(ETHERTYPE_IPX))) { + llc->llc_snap.ether_type == htons(ETHERTYPE_IPX)) && + /* Do not want to touch A-MSDU frames. */ + !(qos & IEEE80211_QOS_AMSDU)) { m_adj(m, hdrlen + sizeof(struct llc) - sizeof(*eh)); llc = NULL; } else { @@ -364,6 +367,10 @@ ieee80211_decap1(struct mbuf *m, int *framelen) #define FF_LLC_SIZE (sizeof(struct ether_header) + sizeof(struct llc)) struct ether_header *eh; struct llc *llc; + const uint8_t llc_hdr_mac[ETHER_ADDR_LEN] = { + /* MAC address matching the 802.2 LLC header */ + LLC_SNAP_LSAP, LLC_SNAP_LSAP, LLC_UI, 0, 0, 0 + }; /* * The frame has an 802.3 header followed by an 802.2 @@ -376,6 +383,15 @@ ieee80211_decap1(struct mbuf *m, int *framelen) if (m->m_len < FF_LLC_SIZE && (m = m_pullup(m, FF_LLC_SIZE)) == NULL) return NULL; eh = mtod(m, struct ether_header *); /* 802.3 header is first */ + + /* + * Detect possible attack where a single 802.11 frame is processed + * as an A-MSDU frame due to an adversary setting the A-MSDU present + * bit in the 802.11 QoS header. [FragAttacks] + */ + if (memcmp(eh->ether_dhost, llc_hdr_mac, ETHER_ADDR_LEN) == 0) + return NULL; + llc = (struct llc *)&eh[1]; /* 802.2 header follows */ *framelen = ntohs(eh->ether_type) /* encap'd frame size */ + sizeof(struct ether_header) - sizeof(struct llc); diff --git a/sys/net80211/ieee80211_input.h b/sys/net80211/ieee80211_input.h index 810dcbde7978..5959319c76d7 100644 --- a/sys/net80211/ieee80211_input.h +++ b/sys/net80211/ieee80211_input.h @@ -311,7 +311,8 @@ void ieee80211_deliver_data(struct ieee80211vap *, struct mbuf *ieee80211_defrag(struct ieee80211_node *, struct mbuf *, int); struct mbuf *ieee80211_realign(struct ieee80211vap *, struct mbuf *, size_t); -struct mbuf *ieee80211_decap(struct ieee80211vap *, struct mbuf *, int); +struct mbuf *ieee80211_decap(struct ieee80211vap *, struct mbuf *, int, + uint8_t); struct mbuf *ieee80211_decap1(struct mbuf *, int *); int ieee80211_setup_rates(struct ieee80211_node *ni, const uint8_t *rates, const uint8_t *xrates, int flags); diff --git a/sys/net80211/ieee80211_sta.c b/sys/net80211/ieee80211_sta.c index f852c4b88b58..90acca07c0e6 100644 --- a/sys/net80211/ieee80211_sta.c +++ b/sys/net80211/ieee80211_sta.c @@ -827,7 +827,7 @@ sta_input(struct ieee80211_node *ni, struct mbuf *m, /* * Finally, strip the 802.11 header. */ - m = ieee80211_decap(vap, m, hdrspace); + m = ieee80211_decap(vap, m, hdrspace, qos); if (m == NULL) { /* XXX mask bit to check for both */ /* don't count Null data frames as errors */ diff --git a/sys/net80211/ieee80211_wds.c b/sys/net80211/ieee80211_wds.c index ea13572cf2d9..74cc764b856e 100644 --- a/sys/net80211/ieee80211_wds.c +++ b/sys/net80211/ieee80211_wds.c @@ -619,7 +619,7 @@ wds_input(struct ieee80211_node *ni, struct mbuf *m, /* * Finally, strip the 802.11 header. */ - m = ieee80211_decap(vap, m, hdrspace); + m = ieee80211_decap(vap, m, hdrspace, qos); if (m == NULL) { /* XXX mask bit to check for both */ /* don't count Null data frames as errors */