638 lines
17 KiB
C
638 lines
17 KiB
C
/*-
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* Copyright (c) 2002-2008 Sam Leffler, Errno Consulting
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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/*
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* IEEE 802.11i AES-CCMP crypto support.
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*
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* Part of this module is derived from similar code in the Host
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* AP driver. The code is used with the consent of the author and
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* it's license is included below.
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*/
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#include "opt_wlan.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/mbuf.h>
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#include <sys/malloc.h>
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#include <sys/kernel.h>
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#include <sys/module.h>
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#include <sys/socket.h>
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#include <net/if.h>
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#include <net/if_media.h>
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#include <net/ethernet.h>
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#include <net80211/ieee80211_var.h>
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#include <crypto/rijndael/rijndael.h>
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#define AES_BLOCK_LEN 16
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struct ccmp_ctx {
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struct ieee80211vap *cc_vap; /* for diagnostics+statistics */
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struct ieee80211com *cc_ic;
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rijndael_ctx cc_aes;
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};
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static void *ccmp_attach(struct ieee80211vap *, struct ieee80211_key *);
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static void ccmp_detach(struct ieee80211_key *);
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static int ccmp_setkey(struct ieee80211_key *);
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static int ccmp_encap(struct ieee80211_key *k, struct mbuf *, uint8_t keyid);
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static int ccmp_decap(struct ieee80211_key *, struct mbuf *, int);
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static int ccmp_enmic(struct ieee80211_key *, struct mbuf *, int);
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static int ccmp_demic(struct ieee80211_key *, struct mbuf *, int);
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static const struct ieee80211_cipher ccmp = {
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.ic_name = "AES-CCM",
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.ic_cipher = IEEE80211_CIPHER_AES_CCM,
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.ic_header = IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN +
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IEEE80211_WEP_EXTIVLEN,
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.ic_trailer = IEEE80211_WEP_MICLEN,
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.ic_miclen = 0,
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.ic_attach = ccmp_attach,
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.ic_detach = ccmp_detach,
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.ic_setkey = ccmp_setkey,
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.ic_encap = ccmp_encap,
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.ic_decap = ccmp_decap,
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.ic_enmic = ccmp_enmic,
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.ic_demic = ccmp_demic,
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};
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static int ccmp_encrypt(struct ieee80211_key *, struct mbuf *, int hdrlen);
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static int ccmp_decrypt(struct ieee80211_key *, u_int64_t pn,
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struct mbuf *, int hdrlen);
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/* number of references from net80211 layer */
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static int nrefs = 0;
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static void *
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ccmp_attach(struct ieee80211vap *vap, struct ieee80211_key *k)
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{
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struct ccmp_ctx *ctx;
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MALLOC(ctx, struct ccmp_ctx *, sizeof(struct ccmp_ctx),
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M_80211_CRYPTO, M_NOWAIT | M_ZERO);
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if (ctx == NULL) {
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vap->iv_stats.is_crypto_nomem++;
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return NULL;
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}
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ctx->cc_vap = vap;
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ctx->cc_ic = vap->iv_ic;
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nrefs++; /* NB: we assume caller locking */
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return ctx;
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}
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static void
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ccmp_detach(struct ieee80211_key *k)
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{
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struct ccmp_ctx *ctx = k->wk_private;
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FREE(ctx, M_80211_CRYPTO);
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KASSERT(nrefs > 0, ("imbalanced attach/detach"));
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nrefs--; /* NB: we assume caller locking */
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}
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static int
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ccmp_setkey(struct ieee80211_key *k)
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{
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struct ccmp_ctx *ctx = k->wk_private;
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if (k->wk_keylen != (128/NBBY)) {
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IEEE80211_DPRINTF(ctx->cc_vap, IEEE80211_MSG_CRYPTO,
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"%s: Invalid key length %u, expecting %u\n",
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__func__, k->wk_keylen, 128/NBBY);
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return 0;
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}
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if (k->wk_flags & IEEE80211_KEY_SWENCRYPT)
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rijndael_set_key(&ctx->cc_aes, k->wk_key, k->wk_keylen*NBBY);
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return 1;
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}
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/*
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* Add privacy headers appropriate for the specified key.
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*/
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static int
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ccmp_encap(struct ieee80211_key *k, struct mbuf *m, uint8_t keyid)
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{
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struct ccmp_ctx *ctx = k->wk_private;
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struct ieee80211com *ic = ctx->cc_ic;
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uint8_t *ivp;
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int hdrlen;
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hdrlen = ieee80211_hdrspace(ic, mtod(m, void *));
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/*
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* Copy down 802.11 header and add the IV, KeyID, and ExtIV.
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*/
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M_PREPEND(m, ccmp.ic_header, M_NOWAIT);
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if (m == NULL)
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return 0;
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ivp = mtod(m, uint8_t *);
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ovbcopy(ivp + ccmp.ic_header, ivp, hdrlen);
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ivp += hdrlen;
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k->wk_keytsc++; /* XXX wrap at 48 bits */
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ivp[0] = k->wk_keytsc >> 0; /* PN0 */
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ivp[1] = k->wk_keytsc >> 8; /* PN1 */
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ivp[2] = 0; /* Reserved */
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ivp[3] = keyid | IEEE80211_WEP_EXTIV; /* KeyID | ExtID */
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ivp[4] = k->wk_keytsc >> 16; /* PN2 */
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ivp[5] = k->wk_keytsc >> 24; /* PN3 */
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ivp[6] = k->wk_keytsc >> 32; /* PN4 */
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ivp[7] = k->wk_keytsc >> 40; /* PN5 */
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/*
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* Finally, do software encrypt if neeed.
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*/
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if ((k->wk_flags & IEEE80211_KEY_SWENCRYPT) &&
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!ccmp_encrypt(k, m, hdrlen))
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return 0;
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return 1;
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}
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/*
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* Add MIC to the frame as needed.
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*/
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static int
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ccmp_enmic(struct ieee80211_key *k, struct mbuf *m, int force)
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{
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return 1;
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}
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static __inline uint64_t
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READ_6(uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3, uint8_t b4, uint8_t b5)
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{
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uint32_t iv32 = (b0 << 0) | (b1 << 8) | (b2 << 16) | (b3 << 24);
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uint16_t iv16 = (b4 << 0) | (b5 << 8);
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return (((uint64_t)iv16) << 32) | iv32;
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}
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/*
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* Validate and strip privacy headers (and trailer) for a
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* received frame. The specified key should be correct but
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* is also verified.
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*/
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static int
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ccmp_decap(struct ieee80211_key *k, struct mbuf *m, int hdrlen)
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{
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struct ccmp_ctx *ctx = k->wk_private;
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struct ieee80211vap *vap = ctx->cc_vap;
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struct ieee80211_frame *wh;
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uint8_t *ivp, tid;
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uint64_t pn;
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/*
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* Header should have extended IV and sequence number;
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* verify the former and validate the latter.
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*/
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wh = mtod(m, struct ieee80211_frame *);
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ivp = mtod(m, uint8_t *) + hdrlen;
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if ((ivp[IEEE80211_WEP_IVLEN] & IEEE80211_WEP_EXTIV) == 0) {
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/*
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* No extended IV; discard frame.
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*/
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IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2,
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"%s", "missing ExtIV for AES-CCM cipher");
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vap->iv_stats.is_rx_ccmpformat++;
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return 0;
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}
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tid = ieee80211_gettid(wh);
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pn = READ_6(ivp[0], ivp[1], ivp[4], ivp[5], ivp[6], ivp[7]);
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if (pn <= k->wk_keyrsc[tid]) {
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/*
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* Replay violation.
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*/
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ieee80211_notify_replay_failure(vap, wh, k, pn);
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vap->iv_stats.is_rx_ccmpreplay++;
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return 0;
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}
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/*
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* Check if the device handled the decrypt in hardware.
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* If so we just strip the header; otherwise we need to
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* handle the decrypt in software. Note that for the
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* latter we leave the header in place for use in the
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* decryption work.
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*/
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if ((k->wk_flags & IEEE80211_KEY_SWDECRYPT) &&
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!ccmp_decrypt(k, pn, m, hdrlen))
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return 0;
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/*
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* Copy up 802.11 header and strip crypto bits.
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*/
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ovbcopy(mtod(m, void *), mtod(m, uint8_t *) + ccmp.ic_header, hdrlen);
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m_adj(m, ccmp.ic_header);
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m_adj(m, -ccmp.ic_trailer);
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/*
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* Ok to update rsc now.
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*/
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k->wk_keyrsc[tid] = pn;
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return 1;
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}
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/*
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* Verify and strip MIC from the frame.
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*/
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static int
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ccmp_demic(struct ieee80211_key *k, struct mbuf *m, int force)
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{
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return 1;
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}
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static __inline void
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xor_block(uint8_t *b, const uint8_t *a, size_t len)
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{
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int i;
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for (i = 0; i < len; i++)
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b[i] ^= a[i];
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}
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/*
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* Host AP crypt: host-based CCMP encryption implementation for Host AP driver
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*
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* Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation. See README and COPYING for
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* more details.
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*
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* Alternatively, this software may be distributed under the terms of BSD
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* license.
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*/
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static void
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ccmp_init_blocks(rijndael_ctx *ctx, struct ieee80211_frame *wh,
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u_int64_t pn, size_t dlen,
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uint8_t b0[AES_BLOCK_LEN], uint8_t aad[2 * AES_BLOCK_LEN],
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uint8_t auth[AES_BLOCK_LEN], uint8_t s0[AES_BLOCK_LEN])
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{
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#define IS_4ADDRESS(wh) \
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((wh->i_fc[1] & IEEE80211_FC1_DIR_MASK) == IEEE80211_FC1_DIR_DSTODS)
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#define IS_QOS_DATA(wh) IEEE80211_QOS_HAS_SEQ(wh)
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/* CCM Initial Block:
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* Flag (Include authentication header, M=3 (8-octet MIC),
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* L=1 (2-octet Dlen))
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* Nonce: 0x00 | A2 | PN
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* Dlen */
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b0[0] = 0x59;
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/* NB: b0[1] set below */
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IEEE80211_ADDR_COPY(b0 + 2, wh->i_addr2);
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b0[8] = pn >> 40;
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b0[9] = pn >> 32;
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b0[10] = pn >> 24;
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b0[11] = pn >> 16;
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b0[12] = pn >> 8;
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b0[13] = pn >> 0;
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b0[14] = (dlen >> 8) & 0xff;
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b0[15] = dlen & 0xff;
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/* AAD:
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* FC with bits 4..6 and 11..13 masked to zero; 14 is always one
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* A1 | A2 | A3
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* SC with bits 4..15 (seq#) masked to zero
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* A4 (if present)
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* QC (if present)
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*/
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aad[0] = 0; /* AAD length >> 8 */
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/* NB: aad[1] set below */
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aad[2] = wh->i_fc[0] & 0x8f; /* XXX magic #s */
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aad[3] = wh->i_fc[1] & 0xc7; /* XXX magic #s */
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/* NB: we know 3 addresses are contiguous */
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memcpy(aad + 4, wh->i_addr1, 3 * IEEE80211_ADDR_LEN);
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aad[22] = wh->i_seq[0] & IEEE80211_SEQ_FRAG_MASK;
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aad[23] = 0; /* all bits masked */
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/*
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* Construct variable-length portion of AAD based
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* on whether this is a 4-address frame/QOS frame.
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* We always zero-pad to 32 bytes before running it
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* through the cipher.
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*
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* We also fill in the priority bits of the CCM
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* initial block as we know whether or not we have
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* a QOS frame.
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*/
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if (IS_4ADDRESS(wh)) {
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IEEE80211_ADDR_COPY(aad + 24,
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((struct ieee80211_frame_addr4 *)wh)->i_addr4);
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if (IS_QOS_DATA(wh)) {
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struct ieee80211_qosframe_addr4 *qwh4 =
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(struct ieee80211_qosframe_addr4 *) wh;
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aad[30] = qwh4->i_qos[0] & 0x0f;/* just priority bits */
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aad[31] = 0;
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b0[1] = aad[30];
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aad[1] = 22 + IEEE80211_ADDR_LEN + 2;
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} else {
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*(uint16_t *)&aad[30] = 0;
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b0[1] = 0;
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aad[1] = 22 + IEEE80211_ADDR_LEN;
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}
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} else {
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if (IS_QOS_DATA(wh)) {
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struct ieee80211_qosframe *qwh =
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(struct ieee80211_qosframe*) wh;
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aad[24] = qwh->i_qos[0] & 0x0f; /* just priority bits */
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aad[25] = 0;
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b0[1] = aad[24];
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aad[1] = 22 + 2;
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} else {
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*(uint16_t *)&aad[24] = 0;
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b0[1] = 0;
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aad[1] = 22;
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}
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*(uint16_t *)&aad[26] = 0;
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*(uint32_t *)&aad[28] = 0;
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}
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/* Start with the first block and AAD */
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rijndael_encrypt(ctx, b0, auth);
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xor_block(auth, aad, AES_BLOCK_LEN);
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rijndael_encrypt(ctx, auth, auth);
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xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN);
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rijndael_encrypt(ctx, auth, auth);
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b0[0] &= 0x07;
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b0[14] = b0[15] = 0;
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rijndael_encrypt(ctx, b0, s0);
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#undef IS_QOS_DATA
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#undef IS_4ADDRESS
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}
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#define CCMP_ENCRYPT(_i, _b, _b0, _pos, _e, _len) do { \
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/* Authentication */ \
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xor_block(_b, _pos, _len); \
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rijndael_encrypt(&ctx->cc_aes, _b, _b); \
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/* Encryption, with counter */ \
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_b0[14] = (_i >> 8) & 0xff; \
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_b0[15] = _i & 0xff; \
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rijndael_encrypt(&ctx->cc_aes, _b0, _e); \
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xor_block(_pos, _e, _len); \
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} while (0)
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static int
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ccmp_encrypt(struct ieee80211_key *key, struct mbuf *m0, int hdrlen)
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{
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struct ccmp_ctx *ctx = key->wk_private;
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struct ieee80211_frame *wh;
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struct mbuf *m = m0;
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int data_len, i, space;
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uint8_t aad[2 * AES_BLOCK_LEN], b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN],
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e[AES_BLOCK_LEN], s0[AES_BLOCK_LEN];
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uint8_t *pos;
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ctx->cc_vap->iv_stats.is_crypto_ccmp++;
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wh = mtod(m, struct ieee80211_frame *);
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data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header);
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ccmp_init_blocks(&ctx->cc_aes, wh, key->wk_keytsc,
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data_len, b0, aad, b, s0);
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i = 1;
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pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header;
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/* NB: assumes header is entirely in first mbuf */
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space = m->m_len - (hdrlen + ccmp.ic_header);
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for (;;) {
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if (space > data_len)
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space = data_len;
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/*
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* Do full blocks.
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*/
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while (space >= AES_BLOCK_LEN) {
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CCMP_ENCRYPT(i, b, b0, pos, e, AES_BLOCK_LEN);
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pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN;
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data_len -= AES_BLOCK_LEN;
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i++;
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}
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if (data_len <= 0) /* no more data */
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break;
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m = m->m_next;
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if (m == NULL) { /* last buffer */
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if (space != 0) {
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/*
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* Short last block.
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*/
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CCMP_ENCRYPT(i, b, b0, pos, e, space);
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}
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break;
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}
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if (space != 0) {
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uint8_t *pos_next;
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int space_next;
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int len, dl, sp;
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struct mbuf *n;
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/*
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* Block straddles one or more mbufs, gather data
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* into the block buffer b, apply the cipher, then
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* scatter the results back into the mbuf chain.
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* The buffer will automatically get space bytes
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* of data at offset 0 copied in+out by the
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* CCMP_ENCRYPT request so we must take care of
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* the remaining data.
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*/
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n = m;
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dl = data_len;
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sp = space;
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for (;;) {
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pos_next = mtod(n, uint8_t *);
|
|
len = min(dl, AES_BLOCK_LEN);
|
|
space_next = len > sp ? len - sp : 0;
|
|
if (n->m_len >= space_next) {
|
|
/*
|
|
* This mbuf has enough data; just grab
|
|
* what we need and stop.
|
|
*/
|
|
xor_block(b+sp, pos_next, space_next);
|
|
break;
|
|
}
|
|
/*
|
|
* This mbuf's contents are insufficient,
|
|
* take 'em all and prepare to advance to
|
|
* the next mbuf.
|
|
*/
|
|
xor_block(b+sp, pos_next, n->m_len);
|
|
sp += n->m_len, dl -= n->m_len;
|
|
n = n->m_next;
|
|
if (n == NULL)
|
|
break;
|
|
}
|
|
|
|
CCMP_ENCRYPT(i, b, b0, pos, e, space);
|
|
|
|
/* NB: just like above, but scatter data to mbufs */
|
|
dl = data_len;
|
|
sp = space;
|
|
for (;;) {
|
|
pos_next = mtod(m, uint8_t *);
|
|
len = min(dl, AES_BLOCK_LEN);
|
|
space_next = len > sp ? len - sp : 0;
|
|
if (m->m_len >= space_next) {
|
|
xor_block(pos_next, e+sp, space_next);
|
|
break;
|
|
}
|
|
xor_block(pos_next, e+sp, m->m_len);
|
|
sp += m->m_len, dl -= m->m_len;
|
|
m = m->m_next;
|
|
if (m == NULL)
|
|
goto done;
|
|
}
|
|
/*
|
|
* Do bookkeeping. m now points to the last mbuf
|
|
* we grabbed data from. We know we consumed a
|
|
* full block of data as otherwise we'd have hit
|
|
* the end of the mbuf chain, so deduct from data_len.
|
|
* Otherwise advance the block number (i) and setup
|
|
* pos+space to reflect contents of the new mbuf.
|
|
*/
|
|
data_len -= AES_BLOCK_LEN;
|
|
i++;
|
|
pos = pos_next + space_next;
|
|
space = m->m_len - space_next;
|
|
} else {
|
|
/*
|
|
* Setup for next buffer.
|
|
*/
|
|
pos = mtod(m, uint8_t *);
|
|
space = m->m_len;
|
|
}
|
|
}
|
|
done:
|
|
/* tack on MIC */
|
|
xor_block(b, s0, ccmp.ic_trailer);
|
|
return m_append(m0, ccmp.ic_trailer, b);
|
|
}
|
|
#undef CCMP_ENCRYPT
|
|
|
|
#define CCMP_DECRYPT(_i, _b, _b0, _pos, _a, _len) do { \
|
|
/* Decrypt, with counter */ \
|
|
_b0[14] = (_i >> 8) & 0xff; \
|
|
_b0[15] = _i & 0xff; \
|
|
rijndael_encrypt(&ctx->cc_aes, _b0, _b); \
|
|
xor_block(_pos, _b, _len); \
|
|
/* Authentication */ \
|
|
xor_block(_a, _pos, _len); \
|
|
rijndael_encrypt(&ctx->cc_aes, _a, _a); \
|
|
} while (0)
|
|
|
|
static int
|
|
ccmp_decrypt(struct ieee80211_key *key, u_int64_t pn, struct mbuf *m, int hdrlen)
|
|
{
|
|
struct ccmp_ctx *ctx = key->wk_private;
|
|
struct ieee80211vap *vap = ctx->cc_vap;
|
|
struct ieee80211_frame *wh;
|
|
uint8_t aad[2 * AES_BLOCK_LEN];
|
|
uint8_t b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], a[AES_BLOCK_LEN];
|
|
uint8_t mic[AES_BLOCK_LEN];
|
|
size_t data_len;
|
|
int i;
|
|
uint8_t *pos;
|
|
u_int space;
|
|
|
|
ctx->cc_vap->iv_stats.is_crypto_ccmp++;
|
|
|
|
wh = mtod(m, struct ieee80211_frame *);
|
|
data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header + ccmp.ic_trailer);
|
|
ccmp_init_blocks(&ctx->cc_aes, wh, pn, data_len, b0, aad, a, b);
|
|
m_copydata(m, m->m_pkthdr.len - ccmp.ic_trailer, ccmp.ic_trailer, mic);
|
|
xor_block(mic, b, ccmp.ic_trailer);
|
|
|
|
i = 1;
|
|
pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header;
|
|
space = m->m_len - (hdrlen + ccmp.ic_header);
|
|
for (;;) {
|
|
if (space > data_len)
|
|
space = data_len;
|
|
while (space >= AES_BLOCK_LEN) {
|
|
CCMP_DECRYPT(i, b, b0, pos, a, AES_BLOCK_LEN);
|
|
pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN;
|
|
data_len -= AES_BLOCK_LEN;
|
|
i++;
|
|
}
|
|
if (data_len <= 0) /* no more data */
|
|
break;
|
|
m = m->m_next;
|
|
if (m == NULL) { /* last buffer */
|
|
if (space != 0) /* short last block */
|
|
CCMP_DECRYPT(i, b, b0, pos, a, space);
|
|
break;
|
|
}
|
|
if (space != 0) {
|
|
uint8_t *pos_next;
|
|
u_int space_next;
|
|
u_int len;
|
|
|
|
/*
|
|
* Block straddles buffers, split references. We
|
|
* do not handle splits that require >2 buffers
|
|
* since rx'd frames are never badly fragmented
|
|
* because drivers typically recv in clusters.
|
|
*/
|
|
pos_next = mtod(m, uint8_t *);
|
|
len = min(data_len, AES_BLOCK_LEN);
|
|
space_next = len > space ? len - space : 0;
|
|
KASSERT(m->m_len >= space_next,
|
|
("not enough data in following buffer, "
|
|
"m_len %u need %u\n", m->m_len, space_next));
|
|
|
|
xor_block(b+space, pos_next, space_next);
|
|
CCMP_DECRYPT(i, b, b0, pos, a, space);
|
|
xor_block(pos_next, b+space, space_next);
|
|
data_len -= len;
|
|
i++;
|
|
|
|
pos = pos_next + space_next;
|
|
space = m->m_len - space_next;
|
|
} else {
|
|
/*
|
|
* Setup for next buffer.
|
|
*/
|
|
pos = mtod(m, uint8_t *);
|
|
space = m->m_len;
|
|
}
|
|
}
|
|
if (memcmp(mic, a, ccmp.ic_trailer) != 0) {
|
|
IEEE80211_NOTE_MAC(vap, IEEE80211_MSG_CRYPTO, wh->i_addr2,
|
|
"%s", "AES-CCM decrypt failed; MIC mismatch");
|
|
vap->iv_stats.is_rx_ccmpmic++;
|
|
return 0;
|
|
}
|
|
return 1;
|
|
}
|
|
#undef CCMP_DECRYPT
|
|
|
|
/*
|
|
* Module glue.
|
|
*/
|
|
IEEE80211_CRYPTO_MODULE(ccmp, 1);
|