From owner-dev-commits-src-all@freebsd.org Thu Sep 30 14:49:35 2021 Return-Path: Delivered-To: dev-commits-src-all@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 4C6DD6B25FE; Thu, 30 Sep 2021 14:49:35 +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 4HKx3M1fQPz3qZ8; Thu, 30 Sep 2021 14:49:35 +0000 (UTC) (envelope-from git@FreeBSD.org) 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 1876B5C2C; Thu, 30 Sep 2021 14:49:35 +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 18UEnZ4P006066; Thu, 30 Sep 2021 14:49:35 GMT (envelope-from git@gitrepo.freebsd.org) Received: (from git@localhost) by gitrepo.freebsd.org (8.16.1/8.16.1/Submit) id 18UEnYIr006065; Thu, 30 Sep 2021 14:49:34 GMT (envelope-from git) Date: Thu, 30 Sep 2021 14:49:34 GMT Message-Id: <202109301449.18UEnYIr006065@gitrepo.freebsd.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org From: "Bjoern A. Zeeb" Subject: git: 11572d7d7fb9 - main - net80211: reject mixed plaintext/encrypted fragments MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Git-Committer: bz X-Git-Repository: src X-Git-Refname: refs/heads/main X-Git-Reftype: branch X-Git-Commit: 11572d7d7fb9802ceb46ea9dc6cbe3bb95373e55 Auto-Submitted: auto-generated X-BeenThere: dev-commits-src-all@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Commit messages for all branches of the src repository List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 30 Sep 2021 14:49:35 -0000 The branch main has been updated by bz: URL: https://cgit.FreeBSD.org/src/commit/?id=11572d7d7fb9802ceb46ea9dc6cbe3bb95373e55 commit 11572d7d7fb9802ceb46ea9dc6cbe3bb95373e55 Author: Mathy Vanhoef AuthorDate: 2021-06-06 22:10:41 +0000 Commit: Bjoern A. Zeeb CommitDate: 2021-09-30 14:47:41 +0000 net80211: reject mixed plaintext/encrypted fragments ieee80211_defrag() accepts fragmented 802.11 frames in a protected Wi-Fi network even when some of the fragments are not encrypted. Track whether the fragments are encrypted or not and only accept successive ones if they match the state of the first fragment. This relates to section 6.3 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-2020-26147 PR: 256118 Differential Revision: https://reviews.freebsd.org/D30663 --- sys/net80211/ieee80211_adhoc.c | 2 +- sys/net80211/ieee80211_hostap.c | 2 +- sys/net80211/ieee80211_input.c | 21 ++++++++++++++++++--- sys/net80211/ieee80211_input.h | 2 +- sys/net80211/ieee80211_mesh.c | 2 +- sys/net80211/ieee80211_sta.c | 2 +- sys/net80211/ieee80211_wds.c | 2 +- 7 files changed, 24 insertions(+), 9 deletions(-) diff --git a/sys/net80211/ieee80211_adhoc.c b/sys/net80211/ieee80211_adhoc.c index ea1519b3381d..a23f138802dc 100644 --- a/sys/net80211/ieee80211_adhoc.c +++ b/sys/net80211/ieee80211_adhoc.c @@ -531,7 +531,7 @@ adhoc_input(struct ieee80211_node *ni, struct mbuf *m, * Next up, any fragmentation. */ if (!IEEE80211_IS_MULTICAST(wh->i_addr1)) { - m = ieee80211_defrag(ni, m, hdrspace); + m = ieee80211_defrag(ni, m, hdrspace, has_decrypted); if (m == NULL) { /* Fragment dropped or frame not complete yet */ goto out; diff --git a/sys/net80211/ieee80211_hostap.c b/sys/net80211/ieee80211_hostap.c index 16a3d97ae7f2..15d42a682355 100644 --- a/sys/net80211/ieee80211_hostap.c +++ b/sys/net80211/ieee80211_hostap.c @@ -719,7 +719,7 @@ hostap_input(struct ieee80211_node *ni, struct mbuf *m, * Next up, any fragmentation. */ if (!IEEE80211_IS_MULTICAST(wh->i_addr1)) { - m = ieee80211_defrag(ni, m, hdrspace); + m = ieee80211_defrag(ni, m, hdrspace, has_decrypted); if (m == NULL) { /* Fragment dropped or frame not complete yet */ goto out; diff --git a/sys/net80211/ieee80211_input.c b/sys/net80211/ieee80211_input.c index aa557fc1ec24..eaeceb9d228e 100644 --- a/sys/net80211/ieee80211_input.c +++ b/sys/net80211/ieee80211_input.c @@ -170,7 +170,8 @@ ieee80211_input_mimo_all(struct ieee80211com *ic, struct mbuf *m) * XXX should handle 3 concurrent reassemblies per-spec. */ struct mbuf * -ieee80211_defrag(struct ieee80211_node *ni, struct mbuf *m, int hdrspace) +ieee80211_defrag(struct ieee80211_node *ni, struct mbuf *m, int hdrspace, + int has_decrypted) { struct ieee80211vap *vap = ni->ni_vap; struct ieee80211_frame *wh = mtod(m, struct ieee80211_frame *); @@ -189,6 +190,11 @@ ieee80211_defrag(struct ieee80211_node *ni, struct mbuf *m, int hdrspace) if (!more_frag && fragno == 0 && ni->ni_rxfrag[0] == NULL) return m; + /* Temporarily set flag to remember if fragment was encrypted. */ + /* XXX use a non-packet altering storage for this in the future. */ + if (has_decrypted) + wh->i_fc[1] |= IEEE80211_FC1_PROTECTED; + /* * Remove frag to insure it doesn't get reaped by timer. */ @@ -219,10 +225,14 @@ ieee80211_defrag(struct ieee80211_node *ni, struct mbuf *m, int hdrspace) lwh = mtod(mfrag, struct ieee80211_frame *); last_rxseq = le16toh(*(uint16_t *)lwh->i_seq); - /* NB: check seq # and frag together */ + /* + * NB: check seq # and frag together. Also check that both + * fragments are plaintext or that both are encrypted. + */ if (rxseq == last_rxseq+1 && IEEE80211_ADDR_EQ(wh->i_addr1, lwh->i_addr1) && - IEEE80211_ADDR_EQ(wh->i_addr2, lwh->i_addr2)) { + IEEE80211_ADDR_EQ(wh->i_addr2, lwh->i_addr2) && + !((wh->i_fc[1] ^ lwh->i_fc[1]) & IEEE80211_FC1_PROTECTED)) { /* XXX clear MORE_FRAG bit? */ /* track last seqnum and fragno */ *(uint16_t *) lwh->i_seq = *(uint16_t *) wh->i_seq; @@ -253,6 +263,11 @@ ieee80211_defrag(struct ieee80211_node *ni, struct mbuf *m, int hdrspace) ni->ni_rxfrag[0] = mfrag; mfrag = NULL; } + /* Remember to clear protected flag that was temporarily set. */ + if (mfrag != NULL) { + wh = mtod(mfrag, struct ieee80211_frame *); + wh->i_fc[1] &= ~IEEE80211_FC1_PROTECTED; + } return mfrag; } diff --git a/sys/net80211/ieee80211_input.h b/sys/net80211/ieee80211_input.h index 7456fc68b365..61e3099cb0a4 100644 --- a/sys/net80211/ieee80211_input.h +++ b/sys/net80211/ieee80211_input.h @@ -309,7 +309,7 @@ fail: void ieee80211_deliver_data(struct ieee80211vap *, struct ieee80211_node *, struct mbuf *); struct mbuf *ieee80211_defrag(struct ieee80211_node *, - struct mbuf *, int); + struct mbuf *, int, int); struct mbuf *ieee80211_realign(struct ieee80211vap *, struct mbuf *, size_t); struct mbuf *ieee80211_decap(struct ieee80211vap *, struct mbuf *, int); struct mbuf *ieee80211_decap1(struct mbuf *, int *); diff --git a/sys/net80211/ieee80211_mesh.c b/sys/net80211/ieee80211_mesh.c index b4326905a7a3..8dcbfa918e3b 100644 --- a/sys/net80211/ieee80211_mesh.c +++ b/sys/net80211/ieee80211_mesh.c @@ -1641,7 +1641,7 @@ mesh_input(struct ieee80211_node *ni, struct mbuf *m, */ hdrspace = ieee80211_hdrspace(ic, wh); if (!IEEE80211_IS_MULTICAST(wh->i_addr1)) { - m = ieee80211_defrag(ni, m, hdrspace); + m = ieee80211_defrag(ni, m, hdrspace, 0); if (m == NULL) { /* Fragment dropped or frame not complete yet */ goto out; diff --git a/sys/net80211/ieee80211_sta.c b/sys/net80211/ieee80211_sta.c index 43dc8b6dfeca..6d24eadc11a6 100644 --- a/sys/net80211/ieee80211_sta.c +++ b/sys/net80211/ieee80211_sta.c @@ -795,7 +795,7 @@ sta_input(struct ieee80211_node *ni, struct mbuf *m, * Next up, any fragmentation. */ if (!IEEE80211_IS_MULTICAST(wh->i_addr1)) { - m = ieee80211_defrag(ni, m, hdrspace); + m = ieee80211_defrag(ni, m, hdrspace, has_decrypted); if (m == NULL) { /* Fragment dropped or frame not complete yet */ goto out; diff --git a/sys/net80211/ieee80211_wds.c b/sys/net80211/ieee80211_wds.c index 8eaffcf87733..f59a92b992d7 100644 --- a/sys/net80211/ieee80211_wds.c +++ b/sys/net80211/ieee80211_wds.c @@ -594,7 +594,7 @@ wds_input(struct ieee80211_node *ni, struct mbuf *m, * Next up, any fragmentation. */ if (!IEEE80211_IS_MULTICAST(wh->i_addr1)) { - m = ieee80211_defrag(ni, m, hdrspace); + m = ieee80211_defrag(ni, m, hdrspace, has_decrypted); if (m == NULL) { /* Fragment dropped or frame not complete yet */ goto out;