1 /* $NetBSD: ieee80211_crypto_ccmp.c,v 1.20 2023/06/24 05:12:03 msaitoh Exp $ */ 2 3 /* 4 * Copyright (c) 2002-2005 Sam Leffler, Errno Consulting 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. The name of the author may not be used to endorse or promote products 16 * derived from this software without specific prior written permission. 17 * 18 * Alternatively, this software may be distributed under the terms of the 19 * GNU General Public License ("GPL") version 2 as published by the Free 20 * Software Foundation. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 #include <sys/cdefs.h> 35 #ifdef __FreeBSD__ 36 __FBSDID("$FreeBSD: src/sys/net80211/ieee80211_crypto_ccmp.c,v 1.7 2005/07/11 03:06:23 sam Exp $"); 37 #endif 38 #ifdef __NetBSD__ 39 __KERNEL_RCSID(0, "$NetBSD: ieee80211_crypto_ccmp.c,v 1.20 2023/06/24 05:12:03 msaitoh Exp $"); 40 #endif 41 42 /* 43 * IEEE 802.11i AES-CCMP crypto support. 44 * 45 * Part of this module is derived from similar code in the Host 46 * AP driver. The code is used with the consent of the author and 47 * its license is included below. 48 */ 49 #include <sys/param.h> 50 #include <sys/kernel.h> 51 #include <sys/kmem.h> 52 #include <sys/mbuf.h> 53 #include <sys/systm.h> 54 55 #include <sys/socket.h> 56 57 #include <net/if.h> 58 #include <net/if_ether.h> 59 #include <net/if_media.h> 60 61 #include <net80211/ieee80211_var.h> 62 63 #include <crypto/aes/aes.h> 64 #include <crypto/aes/aes_ccm.h> 65 #include <crypto/aes/aes_ccm_mbuf.h> 66 67 #define AES_BLOCK_LEN 16 68 69 struct ccmp_ctx { 70 struct aesenc cc_aes; 71 struct ieee80211com *cc_ic; /* for diagnostics */ 72 }; 73 74 static void *ccmp_attach(struct ieee80211com *, struct ieee80211_key *); 75 static void ccmp_detach(struct ieee80211_key *); 76 static int ccmp_setkey(struct ieee80211_key *); 77 static int ccmp_encap(struct ieee80211_key *k, struct mbuf *, u_int8_t keyid); 78 static int ccmp_decap(struct ieee80211_key *, struct mbuf *, int); 79 static int ccmp_enmic(struct ieee80211_key *, struct mbuf *, int); 80 static int ccmp_demic(struct ieee80211_key *, struct mbuf *, int); 81 82 const struct ieee80211_cipher ieee80211_cipher_ccmp = { 83 .ic_name = "AES-CCM", 84 .ic_cipher = IEEE80211_CIPHER_AES_CCM, 85 .ic_header = IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN + 86 IEEE80211_WEP_EXTIVLEN, 87 .ic_trailer = IEEE80211_WEP_MICLEN, 88 .ic_miclen = 0, 89 .ic_attach = ccmp_attach, 90 .ic_detach = ccmp_detach, 91 .ic_setkey = ccmp_setkey, 92 .ic_encap = ccmp_encap, 93 .ic_decap = ccmp_decap, 94 .ic_enmic = ccmp_enmic, 95 .ic_demic = ccmp_demic, 96 }; 97 98 #define ccmp ieee80211_cipher_ccmp 99 100 static int ccmp_encrypt(struct ieee80211_key *, struct mbuf *, int hdrlen); 101 static int ccmp_decrypt(struct ieee80211_key *, u_int64_t pn, 102 struct mbuf *, int hdrlen); 103 104 static void * 105 ccmp_attach(struct ieee80211com *ic, struct ieee80211_key *k) 106 { 107 struct ccmp_ctx *ctx; 108 109 ctx = kmem_intr_zalloc(sizeof(*ctx), KM_NOSLEEP); 110 if (ctx == NULL) { 111 ic->ic_stats.is_crypto_nomem++; 112 return NULL; 113 } 114 ctx->cc_ic = ic; 115 return ctx; 116 } 117 118 static void 119 ccmp_detach(struct ieee80211_key *k) 120 { 121 struct ccmp_ctx *ctx = k->wk_private; 122 123 kmem_intr_free(ctx, sizeof(*ctx)); 124 } 125 126 static int 127 ccmp_setkey(struct ieee80211_key *k) 128 { 129 struct ccmp_ctx *ctx = k->wk_private; 130 131 if (k->wk_keylen != (128/NBBY)) { 132 IEEE80211_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO, 133 "%s: Invalid key length %u, expecting %u\n", 134 __func__, k->wk_keylen, 128/NBBY); 135 return 0; 136 } 137 if (k->wk_flags & IEEE80211_KEY_SWCRYPT) 138 aes_setenckey128(&ctx->cc_aes, k->wk_key); 139 return 1; 140 } 141 142 /* 143 * Add privacy headers appropriate for the specified key. 144 */ 145 static int 146 ccmp_encap(struct ieee80211_key *k, struct mbuf *m, u_int8_t keyid) 147 { 148 struct ccmp_ctx *ctx = k->wk_private; 149 struct ieee80211com *ic = ctx->cc_ic; 150 u_int8_t *ivp; 151 int hdrlen; 152 153 hdrlen = ieee80211_hdrspace(ic, mtod(m, void *)); 154 ivp = mtod(m, u_int8_t *) + hdrlen; 155 156 k->wk_keytsc++; /* XXX wrap at 48 bits */ 157 ivp[0] = k->wk_keytsc >> 0; /* PN0 */ 158 ivp[1] = k->wk_keytsc >> 8; /* PN1 */ 159 ivp[2] = 0; /* Reserved */ 160 ivp[3] = keyid | IEEE80211_WEP_EXTIV; /* KeyID | ExtID */ 161 ivp[4] = k->wk_keytsc >> 16; /* PN2 */ 162 ivp[5] = k->wk_keytsc >> 24; /* PN3 */ 163 ivp[6] = k->wk_keytsc >> 32; /* PN4 */ 164 ivp[7] = k->wk_keytsc >> 40; /* PN5 */ 165 166 /* 167 * Finally, do software encrypt if need. 168 */ 169 if ((k->wk_flags & IEEE80211_KEY_SWCRYPT) && 170 !ccmp_encrypt(k, m, hdrlen)) 171 return 0; 172 173 return 1; 174 } 175 176 /* 177 * Add MIC to the frame as needed. 178 */ 179 static int 180 ccmp_enmic(struct ieee80211_key *k, struct mbuf *m, 181 int force) 182 { 183 184 return 1; 185 } 186 187 static __inline uint64_t 188 READ_6(uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3, uint8_t b4, uint8_t b5) 189 { 190 uint32_t iv32 = (b0 << 0) | (b1 << 8) | (b2 << 16) | (b3 << 24); 191 uint16_t iv16 = (b4 << 0) | (b5 << 8); 192 return (((uint64_t)iv16) << 32) | iv32; 193 } 194 195 /* 196 * Validate and strip privacy headers (and trailer) for a 197 * received frame. The specified key should be correct but 198 * is also verified. 199 */ 200 static int 201 ccmp_decap(struct ieee80211_key *k, struct mbuf *m, int hdrlen) 202 { 203 struct ccmp_ctx *ctx = k->wk_private; 204 struct ieee80211_frame *wh; 205 uint8_t *ivp; 206 uint64_t pn; 207 208 /* 209 * Header should have extended IV and sequence number; 210 * verify the former and validate the latter. 211 */ 212 wh = mtod(m, struct ieee80211_frame *); 213 ivp = mtod(m, uint8_t *) + hdrlen; 214 if ((ivp[IEEE80211_WEP_IVLEN] & IEEE80211_WEP_EXTIV) == 0) { 215 /* 216 * No extended IV; discard frame. 217 */ 218 IEEE80211_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO, 219 "[%s] Missing ExtIV for AES-CCM cipher\n", 220 ether_sprintf(wh->i_addr2)); 221 ctx->cc_ic->ic_stats.is_rx_ccmpformat++; 222 return 0; 223 } 224 pn = READ_6(ivp[0], ivp[1], ivp[4], ivp[5], ivp[6], ivp[7]); 225 if (pn <= k->wk_keyrsc) { 226 /* 227 * Replay violation. 228 */ 229 ieee80211_notify_replay_failure(ctx->cc_ic, wh, k, pn); 230 ctx->cc_ic->ic_stats.is_rx_ccmpreplay++; 231 return 0; 232 } 233 234 /* 235 * Check if the device handled the decrypt in hardware. 236 * If so we just strip the header; otherwise we need to 237 * handle the decrypt in software. Note that for the 238 * latter we leave the header in place for use in the 239 * decryption work. 240 */ 241 if ((k->wk_flags & IEEE80211_KEY_SWCRYPT) && 242 !ccmp_decrypt(k, pn, m, hdrlen)) 243 return 0; 244 245 /* 246 * Copy up 802.11 header and strip crypto bits. 247 */ 248 memmove(mtod(m, u_int8_t *) + ccmp.ic_header, mtod(m, void *), hdrlen); 249 m_adj(m, ccmp.ic_header); 250 m_adj(m, -ccmp.ic_trailer); 251 252 /* 253 * Ok to update rsc now. 254 */ 255 k->wk_keyrsc = pn; 256 257 return 1; 258 } 259 260 /* 261 * Verify and strip MIC from the frame. 262 */ 263 static int 264 ccmp_demic(struct ieee80211_key *k, struct mbuf *m, int force) 265 { 266 return 1; 267 } 268 269 /* 270 * Host AP crypt: host-based CCMP encryption implementation for Host AP driver 271 * 272 * Copyright (c) 2003-2004, Jouni Malinen <jkmaline (at) cc.hut.fi> 273 * 274 * This program is free software; you can redistribute it and/or modify 275 * it under the terms of the GNU General Public License version 2 as 276 * published by the Free Software Foundation. See README and COPYING for 277 * more details. 278 * 279 * Alternatively, this software may be distributed under the terms of BSD 280 * license. 281 */ 282 283 static void 284 ccmp_init_blocks(struct aesenc *ctx, struct ieee80211_frame *wh, 285 u_int64_t pn, size_t data_len, struct aes_ccm *aes_ccm) 286 { 287 uint8_t nonce[13]; 288 uint8_t ad[32]; 289 uint8_t qos; 290 size_t adlen; 291 292 #define IS_4ADDRESS(wh) \ 293 ((wh->i_fc[1] & IEEE80211_FC1_DIR_MASK) == IEEE80211_FC1_DIR_DSTODS) 294 #define IS_QOS_DATA(wh) ieee80211_has_qos(wh) 295 296 /* nonce[0] is qos, determined later */ 297 IEEE80211_ADDR_COPY(nonce + 1, wh->i_addr2); 298 nonce[7] = pn >> 40; 299 nonce[8] = pn >> 32; 300 nonce[9] = pn >> 24; 301 nonce[10] = pn >> 16; 302 nonce[11] = pn >> 8; 303 nonce[12] = pn >> 0; 304 305 ad[0] = wh->i_fc[0] & 0x8f; /* XXX magic #s */ 306 ad[1] = wh->i_fc[1] & 0xc7; /* XXX magic #s */ 307 /* NB: we know 3 addresses are contiguous */ 308 memcpy(ad + 2, wh->i_addr1, 3 * IEEE80211_ADDR_LEN); 309 ad[20] = wh->i_seq[0] & IEEE80211_SEQ_FRAG_MASK; 310 ad[21] = 0; /* all bits masked */ 311 312 /* 313 * Construct variable-length portion of AAD based 314 * on whether this is a 4-address frame/QOS frame. 315 * 316 * We also fill in the priority bits of the CCM 317 * initial block as we know whether or not we have 318 * a QOS frame. 319 */ 320 if (IS_4ADDRESS(wh)) { 321 IEEE80211_ADDR_COPY(ad + 22, 322 ((const struct ieee80211_frame_addr4 *)wh)->i_addr4); 323 if (IS_QOS_DATA(wh)) { 324 const struct ieee80211_qosframe_addr4 *qwh4 = 325 (const struct ieee80211_qosframe_addr4 *)wh; 326 qos = qwh4->i_qos[0] & 0x0f; /* just priority bits */ 327 ad[28] = qos; 328 ad[29] = 0; 329 adlen = 22 + IEEE80211_ADDR_LEN + 2; 330 } else { 331 qos = 0; 332 adlen = 22 + IEEE80211_ADDR_LEN; 333 } 334 } else { 335 if (IS_QOS_DATA(wh)) { 336 const struct ieee80211_qosframe *qwh = 337 (const struct ieee80211_qosframe *)wh; 338 qos = qwh->i_qos[0] & 0x0f; /* just priority bits */ 339 ad[22] = qos; 340 ad[23] = 0; 341 adlen = 22 + 2; 342 } else { 343 qos = 0; 344 adlen = 22; 345 } 346 } 347 nonce[0] = qos; 348 349 aes_ccm_init(aes_ccm, AES_128_NROUNDS, ctx, 2 /* L, counter octets */, 350 IEEE80211_WEP_MICLEN, nonce, sizeof nonce, ad, adlen, data_len); 351 352 #undef IS_QOS_DATA 353 #undef IS_4ADDRESS 354 } 355 356 static int 357 ccmp_encrypt(struct ieee80211_key *key, struct mbuf *m, int hdrlen) 358 { 359 struct ccmp_ctx *ctx = key->wk_private; 360 struct ieee80211_frame *wh; 361 struct aes_ccm aes_ccm; 362 size_t data_len; 363 uint8_t mic[IEEE80211_WEP_MICLEN]; 364 365 KASSERT(hdrlen >= 0); 366 KASSERT(hdrlen < m->m_pkthdr.len); 367 KASSERT(ccmp.ic_header <= m->m_pkthdr.len - hdrlen); 368 369 ctx->cc_ic->ic_stats.is_crypto_ccmp++; 370 371 wh = mtod(m, struct ieee80211_frame *); 372 data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header); 373 ccmp_init_blocks(&ctx->cc_aes, wh, key->wk_keytsc, data_len, &aes_ccm); 374 aes_ccm_enc_mbuf(&aes_ccm, m, hdrlen + ccmp.ic_header, data_len, mic); 375 376 return m_append(m, ccmp.ic_trailer, mic); 377 } 378 379 static int 380 ccmp_decrypt(struct ieee80211_key *key, u_int64_t pn, struct mbuf *m, 381 int hdrlen) 382 { 383 struct ccmp_ctx *ctx = key->wk_private; 384 struct ieee80211_frame *wh; 385 struct aes_ccm aes_ccm; 386 size_t data_len; 387 uint8_t mic[IEEE80211_WEP_MICLEN]; 388 389 KASSERT(hdrlen >= 0); 390 KASSERT(hdrlen < m->m_pkthdr.len); 391 KASSERT(ccmp.ic_header < m->m_pkthdr.len - hdrlen); 392 KASSERT(ccmp.ic_trailer < m->m_pkthdr.len - (hdrlen + ccmp.ic_header)); 393 394 ctx->cc_ic->ic_stats.is_crypto_ccmp++; 395 396 wh = mtod(m, struct ieee80211_frame *); 397 data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header + ccmp.ic_trailer); 398 ccmp_init_blocks(&ctx->cc_aes, wh, pn, data_len, &aes_ccm); 399 m_copydata(m, m->m_pkthdr.len - ccmp.ic_trailer, ccmp.ic_trailer, mic); 400 401 if (!aes_ccm_dec_mbuf(&aes_ccm, m, hdrlen + ccmp.ic_header, data_len, 402 mic)) { 403 IEEE80211_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO, 404 "[%s] AES-CCM decrypt failed; MIC mismatch\n", 405 ether_sprintf(wh->i_addr2)); 406 ctx->cc_ic->ic_stats.is_rx_ccmpmic++; 407 return 0; 408 } 409 410 return 1; 411 } 412 413 IEEE80211_CRYPTO_SETUP(ccmp_register) 414 { 415 ieee80211_crypto_register(&ccmp); 416 } 417
Indexes created Sat Sep 20 22:09:52 GMT 2025