/*- * Copyright (c) 2002-2005 Sam Leffler, Errno Consulting * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * Alternatively, this software may be distributed under the terms of the * GNU General Public License ("GPL") version 2 as published by the Free * Software Foundation. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include #ifdef __FreeBSD__ __FBSDID("$FreeBSD: src/sys/net80211/ieee80211_crypto_ccmp.c,v 1.7 2005/07/11 03:06:23 sam Exp $"); #endif #ifdef __NetBSD__ __KERNEL_RCSID(0, "$NetBSD: ieee80211_crypto_ccmp.c,v 1.11 2014/10/18 08:33:29 snj Exp $"); #endif /* * IEEE 802.11i AES-CCMP crypto support. * * Part of this module is derived from similar code in the Host * AP driver. The code is used with the consent of the author and * its license is included below. */ #include #include #include #include #include #include #include #include #include #include #include #define AES_BLOCK_LEN 16 struct ccmp_ctx { struct ieee80211com *cc_ic; /* for diagnostics */ rijndael_ctx cc_aes; }; static void *ccmp_attach(struct ieee80211com *, struct ieee80211_key *); static void ccmp_detach(struct ieee80211_key *); static int ccmp_setkey(struct ieee80211_key *); static int ccmp_encap(struct ieee80211_key *k, struct mbuf *, u_int8_t keyid); static int ccmp_decap(struct ieee80211_key *, struct mbuf *, int); static int ccmp_enmic(struct ieee80211_key *, struct mbuf *, int); static int ccmp_demic(struct ieee80211_key *, struct mbuf *, int); const struct ieee80211_cipher ieee80211_cipher_ccmp = { .ic_name = "AES-CCM", .ic_cipher = IEEE80211_CIPHER_AES_CCM, .ic_header = IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN + IEEE80211_WEP_EXTIVLEN, .ic_trailer = IEEE80211_WEP_MICLEN, .ic_miclen = 0, .ic_attach = ccmp_attach, .ic_detach = ccmp_detach, .ic_setkey = ccmp_setkey, .ic_encap = ccmp_encap, .ic_decap = ccmp_decap, .ic_enmic = ccmp_enmic, .ic_demic = ccmp_demic, }; #define ccmp ieee80211_cipher_ccmp static int ccmp_encrypt(struct ieee80211_key *, struct mbuf *, int hdrlen); static int ccmp_decrypt(struct ieee80211_key *, u_int64_t pn, struct mbuf *, int hdrlen); static void * ccmp_attach(struct ieee80211com *ic, struct ieee80211_key *k) { struct ccmp_ctx *ctx; ctx = malloc(sizeof(struct ccmp_ctx), M_DEVBUF, M_NOWAIT | M_ZERO); if (ctx == NULL) { ic->ic_stats.is_crypto_nomem++; return NULL; } ctx->cc_ic = ic; return ctx; } static void ccmp_detach(struct ieee80211_key *k) { struct ccmp_ctx *ctx = k->wk_private; free(ctx, M_DEVBUF); } static int ccmp_setkey(struct ieee80211_key *k) { struct ccmp_ctx *ctx = k->wk_private; if (k->wk_keylen != (128/NBBY)) { IEEE80211_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO, "%s: Invalid key length %u, expecting %u\n", __func__, k->wk_keylen, 128/NBBY); return 0; } if (k->wk_flags & IEEE80211_KEY_SWCRYPT) rijndael_set_key(&ctx->cc_aes, k->wk_key, k->wk_keylen*NBBY); return 1; } /* * Add privacy headers appropriate for the specified key. */ static int ccmp_encap(struct ieee80211_key *k, struct mbuf *m, u_int8_t keyid) { struct ccmp_ctx *ctx = k->wk_private; struct ieee80211com *ic = ctx->cc_ic; u_int8_t *ivp; int hdrlen; hdrlen = ieee80211_hdrspace(ic, mtod(m, void *)); /* * Copy down 802.11 header and add the IV, KeyID, and ExtIV. */ M_PREPEND(m, ccmp.ic_header, M_NOWAIT); if (m == NULL) return 0; ivp = mtod(m, u_int8_t *); ovbcopy(ivp + ccmp.ic_header, ivp, hdrlen); ivp += hdrlen; k->wk_keytsc++; /* XXX wrap at 48 bits */ ivp[0] = k->wk_keytsc >> 0; /* PN0 */ ivp[1] = k->wk_keytsc >> 8; /* PN1 */ ivp[2] = 0; /* Reserved */ ivp[3] = keyid | IEEE80211_WEP_EXTIV; /* KeyID | ExtID */ ivp[4] = k->wk_keytsc >> 16; /* PN2 */ ivp[5] = k->wk_keytsc >> 24; /* PN3 */ ivp[6] = k->wk_keytsc >> 32; /* PN4 */ ivp[7] = k->wk_keytsc >> 40; /* PN5 */ /* * Finally, do software encrypt if neeed. */ if ((k->wk_flags & IEEE80211_KEY_SWCRYPT) && !ccmp_encrypt(k, m, hdrlen)) return 0; return 1; } /* * Add MIC to the frame as needed. */ static int ccmp_enmic(struct ieee80211_key *k, struct mbuf *m, int force) { return 1; } static __inline uint64_t READ_6(uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3, uint8_t b4, uint8_t b5) { uint32_t iv32 = (b0 << 0) | (b1 << 8) | (b2 << 16) | (b3 << 24); uint16_t iv16 = (b4 << 0) | (b5 << 8); return (((uint64_t)iv16) << 32) | iv32; } /* * Validate and strip privacy headers (and trailer) for a * received frame. The specified key should be correct but * is also verified. */ static int ccmp_decap(struct ieee80211_key *k, struct mbuf *m, int hdrlen) { struct ccmp_ctx *ctx = k->wk_private; struct ieee80211_frame *wh; uint8_t *ivp; uint64_t pn; /* * Header should have extended IV and sequence number; * verify the former and validate the latter. */ wh = mtod(m, struct ieee80211_frame *); ivp = mtod(m, uint8_t *) + hdrlen; if ((ivp[IEEE80211_WEP_IVLEN] & IEEE80211_WEP_EXTIV) == 0) { /* * No extended IV; discard frame. */ IEEE80211_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO, "[%s] Missing ExtIV for AES-CCM cipher\n", ether_sprintf(wh->i_addr2)); ctx->cc_ic->ic_stats.is_rx_ccmpformat++; return 0; } pn = READ_6(ivp[0], ivp[1], ivp[4], ivp[5], ivp[6], ivp[7]); if (pn <= k->wk_keyrsc) { /* * Replay violation. */ ieee80211_notify_replay_failure(ctx->cc_ic, wh, k, pn); ctx->cc_ic->ic_stats.is_rx_ccmpreplay++; return 0; } /* * Check if the device handled the decrypt in hardware. * If so we just strip the header; otherwise we need to * handle the decrypt in software. Note that for the * latter we leave the header in place for use in the * decryption work. */ if ((k->wk_flags & IEEE80211_KEY_SWCRYPT) && !ccmp_decrypt(k, pn, m, hdrlen)) return 0; /* * Copy up 802.11 header and strip crypto bits. */ ovbcopy(mtod(m, void *), mtod(m, u_int8_t *) + ccmp.ic_header, hdrlen); m_adj(m, ccmp.ic_header); m_adj(m, -ccmp.ic_trailer); /* * Ok to update rsc now. */ k->wk_keyrsc = pn; return 1; } /* * Verify and strip MIC from the frame. */ static int ccmp_demic(struct ieee80211_key *k, struct mbuf *m, int force) { return 1; } static __inline void xor_block(uint8_t *b, const uint8_t *a, size_t len) { int i; for (i = 0; i < len; i++) b[i] ^= a[i]; } /* * Host AP crypt: host-based CCMP encryption implementation for Host AP driver * * Copyright (c) 2003-2004, Jouni Malinen * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. See README and COPYING for * more details. * * Alternatively, this software may be distributed under the terms of BSD * license. */ static void ccmp_init_blocks(rijndael_ctx *ctx, struct ieee80211_frame *wh, u_int64_t pn, size_t dlen, uint8_t b0[AES_BLOCK_LEN], uint8_t aad[2 * AES_BLOCK_LEN], uint8_t auth[AES_BLOCK_LEN], uint8_t s0[AES_BLOCK_LEN]) { #define IS_4ADDRESS(wh) \ ((wh->i_fc[1] & IEEE80211_FC1_DIR_MASK) == IEEE80211_FC1_DIR_DSTODS) #define IS_QOS_DATA(wh) ieee80211_has_qos(wh) /* CCM Initial Block: * Flag (Include authentication header, M=3 (8-octet MIC), * L=1 (2-octet Dlen)) * Nonce: 0x00 | A2 | PN * Dlen */ b0[0] = 0x59; /* NB: b0[1] set below */ IEEE80211_ADDR_COPY(b0 + 2, wh->i_addr2); b0[8] = pn >> 40; b0[9] = pn >> 32; b0[10] = pn >> 24; b0[11] = pn >> 16; b0[12] = pn >> 8; b0[13] = pn >> 0; b0[14] = (dlen >> 8) & 0xff; b0[15] = dlen & 0xff; /* AAD: * FC with bits 4..6 and 11..13 masked to zero; 14 is always one * A1 | A2 | A3 * SC with bits 4..15 (seq#) masked to zero * A4 (if present) * QC (if present) */ aad[0] = 0; /* AAD length >> 8 */ /* NB: aad[1] set below */ aad[2] = wh->i_fc[0] & 0x8f; /* XXX magic #s */ aad[3] = wh->i_fc[1] & 0xc7; /* XXX magic #s */ /* NB: we know 3 addresses are contiguous */ memcpy(aad + 4, wh->i_addr1, 3 * IEEE80211_ADDR_LEN); aad[22] = wh->i_seq[0] & IEEE80211_SEQ_FRAG_MASK; aad[23] = 0; /* all bits masked */ /* * Construct variable-length portion of AAD based * on whether this is a 4-address frame/QOS frame. * We always zero-pad to 32 bytes before running it * through the cipher. * * We also fill in the priority bits of the CCM * initial block as we know whether or not we have * a QOS frame. */ if (IS_4ADDRESS(wh)) { IEEE80211_ADDR_COPY(aad + 24, ((struct ieee80211_frame_addr4 *)wh)->i_addr4); if (IS_QOS_DATA(wh)) { struct ieee80211_qosframe_addr4 *qwh4 = (struct ieee80211_qosframe_addr4 *) wh; aad[30] = qwh4->i_qos[0] & 0x0f;/* just priority bits */ aad[31] = 0; b0[1] = aad[30]; aad[1] = 22 + IEEE80211_ADDR_LEN + 2; } else { *(u_int16_t *)&aad[30] = 0; b0[1] = 0; aad[1] = 22 + IEEE80211_ADDR_LEN; } } else { if (IS_QOS_DATA(wh)) { struct ieee80211_qosframe *qwh = (struct ieee80211_qosframe*) wh; aad[24] = qwh->i_qos[0] & 0x0f; /* just priority bits */ aad[25] = 0; b0[1] = aad[24]; aad[1] = 22 + 2; } else { *(u_int16_t *)&aad[24] = 0; b0[1] = 0; aad[1] = 22; } *(u_int16_t *)&aad[26] = 0; *(u_int32_t *)&aad[28] = 0; } /* Start with the first block and AAD */ rijndael_encrypt(ctx, b0, auth); xor_block(auth, aad, AES_BLOCK_LEN); rijndael_encrypt(ctx, auth, auth); xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN); rijndael_encrypt(ctx, auth, auth); b0[0] &= 0x07; b0[14] = b0[15] = 0; rijndael_encrypt(ctx, b0, s0); #undef IS_QOS_DATA #undef IS_4ADDRESS } #define CCMP_ENCRYPT(_i, _b, _b0, _pos, _e, _len) do { \ /* Authentication */ \ xor_block(_b, _pos, _len); \ rijndael_encrypt(&ctx->cc_aes, _b, _b); \ /* Encryption, with counter */ \ _b0[14] = (_i >> 8) & 0xff; \ _b0[15] = _i & 0xff; \ rijndael_encrypt(&ctx->cc_aes, _b0, _e); \ xor_block(_pos, _e, _len); \ } while (0) static int ccmp_encrypt(struct ieee80211_key *key, struct mbuf *m0, int hdrlen) { struct ccmp_ctx *ctx = key->wk_private; struct ieee80211_frame *wh; struct mbuf *m = m0; int data_len, i, space; uint8_t aad[2 * AES_BLOCK_LEN], b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], e[AES_BLOCK_LEN], s0[AES_BLOCK_LEN]; uint8_t *pos; ctx->cc_ic->ic_stats.is_crypto_ccmp++; wh = mtod(m, struct ieee80211_frame *); data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header); ccmp_init_blocks(&ctx->cc_aes, wh, key->wk_keytsc, data_len, b0, aad, b, s0); i = 1; pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header; /* NB: assumes header is entirely in first mbuf */ space = m->m_len - (hdrlen + ccmp.ic_header); for (;;) { if (space > data_len) space = data_len; /* * Do full blocks. */ while (space >= AES_BLOCK_LEN) { CCMP_ENCRYPT(i, b, b0, pos, e, 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_ENCRYPT(i, b, b0, pos, e, space); } break; } if (space != 0) { uint8_t *pos_next; int space_next; int len, dl, sp; struct mbuf *n; /* * Block straddles one or more mbufs, gather data * into the block buffer b, apply the cipher, then * scatter the results back into the mbuf chain. * The buffer will automatically get space bytes * of data at offset 0 copied in+out by the * CCMP_ENCRYPT request so we must take care of * the remaining data. */ n = m; dl = data_len; sp = space; for (;;) { 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 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_ic->ic_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; IASSERT(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_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO, "[%s] AES-CCM decrypt failed; MIC mismatch\n", ether_sprintf(wh->i_addr2)); ctx->cc_ic->ic_stats.is_rx_ccmpmic++; return 0; } return 1; } #undef CCMP_DECRYPT IEEE80211_CRYPTO_SETUP(ccmp_register) { ieee80211_crypto_register(&ccmp); }