1 /* 2 * Copyright 2007 Sun Microsystems, Inc. All rights reserved. 3 * Use is subject to license terms. 4 */ 5 6 /* 7 * Copyright (c) 2001 Atsushi Onoe 8 * Copyright (c) 2002-2005 Sam Leffler, Errno Consulting 9 * All rights reserved. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. The name of the author may not be used to endorse or promote products 20 * derived from this software without specific prior written permission. 21 * 22 * Alternatively, this software may be distributed under the terms of the 23 * GNU General Public License ("GPL") version 2 as published by the Free 24 * Software Foundation. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 27 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 28 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 29 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 30 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 31 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 35 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 36 */ 37 38 #pragma ident "%Z%%M% %I% %E% SMI" 39 40 /* 41 * IEEE 802.11 generic crypto support 42 */ 43 #include <sys/types.h> 44 #include <sys/note.h> 45 #include "net80211_impl.h" 46 47 extern const struct ieee80211_cipher wep; 48 extern const struct ieee80211_cipher tkip; 49 extern const struct ieee80211_cipher ccmp; 50 51 /* 52 * Table of registered cipher modules. 53 */ 54 static const struct ieee80211_cipher *ciphers[IEEE80211_CIPHER_MAX]; 55 static const char *cipher_modnames[] = { 56 "wlan_wep", /* IEEE80211_CIPHER_WEP */ 57 "wlan_tkip", /* IEEE80211_CIPHER_TKIP */ 58 "wlan_aes_ocb", /* IEEE80211_CIPHER_AES_OCB */ 59 "wlan_ccmp", /* IEEE80211_CIPHER_AES_CCM */ 60 "wlan_ckip", /* IEEE80211_CIPHER_CKIP */ 61 }; 62 63 /* 64 * Default "null" key management routines. 65 */ 66 /* ARGSUSED */ 67 static int 68 nulldev_key_alloc(ieee80211com_t *ic, const struct ieee80211_key *k, 69 ieee80211_keyix *keyix, ieee80211_keyix *rxkeyix) 70 { 71 *keyix = 0; /* use key index 0 for ucast key */ 72 *rxkeyix = IEEE80211_KEYIX_NONE; 73 return (1); 74 } 75 76 /* ARGSUSED */ 77 static int 78 nulldev_key_delete(ieee80211com_t *ic, const struct ieee80211_key *k) 79 { 80 return (1); 81 } 82 83 /* ARGSUSED */ 84 static int 85 nulldev_key_set(ieee80211com_t *ic, const struct ieee80211_key *k, 86 const uint8_t *mac) 87 { 88 return (1); 89 } 90 91 /* ARGSUSED */ 92 static void 93 nulldev_key_update(ieee80211com_t *ic) 94 { 95 /* noop */ 96 } 97 98 /* 99 * Reset key state to an unused state. The crypto 100 * key allocation mechanism insures other state (e.g. 101 * key data) is properly setup before a key is used. 102 */ 103 void 104 ieee80211_crypto_resetkey(ieee80211com_t *ic, 105 struct ieee80211_key *k, ieee80211_keyix ix) 106 { 107 k->wk_cipher = &ieee80211_cipher_none; 108 k->wk_private = k->wk_cipher->ic_attach(ic, k); 109 k->wk_keyix = ix; 110 k->wk_flags = IEEE80211_KEY_XMIT | IEEE80211_KEY_RECV; 111 } 112 113 /* 114 * Establish a relationship between the specified key and cipher 115 * and, if necessary, allocate a hardware index from the driver. 116 * Note that when a fixed key index is required it must be specified 117 * and we blindly assign it w/o consulting the driver. 118 * 119 * This must be the first call applied to a key; all the other key 120 * routines assume wk_cipher is setup. 121 * 122 * Locking must be handled by the caller using: 123 * ieee80211_key_update_begin(ic); 124 * ieee80211_key_update_end(ic); 125 */ 126 int 127 ieee80211_crypto_newkey(ieee80211com_t *ic, int cipher, int flags, 128 struct ieee80211_key *key) 129 { 130 const struct ieee80211_cipher *cip; 131 ieee80211_keyix keyix, rxkeyix; 132 void *keyctx; 133 uint16_t oflags; 134 135 /* 136 * Validate cipher and set reference to cipher routines. 137 */ 138 if (cipher >= IEEE80211_CIPHER_MAX) { 139 ieee80211_dbg(IEEE80211_MSG_CRYPTO, "ieee80211_crypto_newkey: " 140 "invalid cipher %u\n", cipher); 141 return (0); 142 } 143 cip = ciphers[cipher]; 144 /* already load all the ciphers, cip can't be NULL */ 145 if (cip == NULL) { 146 ieee80211_dbg(IEEE80211_MSG_CRYPTO, "ieee80211_crypto_newkey: " 147 "unable to load cipher %u, module %s\n", 148 cipher, cipher < IEEE80211_N(cipher_modnames) ? 149 cipher_modnames[cipher] : "<unknown>"); 150 return (0); 151 } 152 153 oflags = key->wk_flags; 154 flags &= IEEE80211_KEY_COMMON; 155 /* 156 * If the hardware does not support the cipher then 157 * fallback to a host-based implementation. 158 */ 159 if ((ic->ic_caps & (1<<cipher)) == 0) { 160 ieee80211_dbg(IEEE80211_MSG_CRYPTO, "ieee80211_crypto_newkey: " 161 "no h/w support for cipher %s, falling back to s/w\n", 162 cip->ic_name); 163 flags |= IEEE80211_KEY_SWCRYPT; 164 } 165 /* 166 * Hardware TKIP with software MIC is an important 167 * combination; we handle it by flagging each key, 168 * the cipher modules honor it. 169 */ 170 if (cipher == IEEE80211_CIPHER_TKIP && 171 (ic->ic_caps & IEEE80211_C_TKIPMIC) == 0) { 172 ieee80211_dbg(IEEE80211_MSG_CRYPTO, 173 "no h/w support for TKIP MIC, falling back to s/w\n"); 174 flags |= IEEE80211_KEY_SWMIC; 175 } 176 177 /* 178 * Bind cipher to key instance. Note we do this 179 * after checking the device capabilities so the 180 * cipher module can optimize space usage based on 181 * whether or not it needs to do the cipher work. 182 */ 183 if (key->wk_cipher != cip || key->wk_flags != flags) { 184 again: 185 /* 186 * Fillin the flags so cipher modules can see s/w 187 * crypto requirements and potentially allocate 188 * different state and/or attach different method 189 * pointers. 190 */ 191 key->wk_flags = (uint16_t)flags; 192 keyctx = cip->ic_attach(ic, key); 193 if (keyctx == NULL) { 194 ieee80211_dbg(IEEE80211_MSG_CRYPTO, "crypto_setkey: " 195 "unable to attach cipher %s\n", cip->ic_name); 196 key->wk_flags = oflags; /* restore old flags */ 197 return (0); 198 } 199 CIPHER_DETACH(key); /* Detach old cipher */ 200 key->wk_cipher = cip; 201 key->wk_private = keyctx; 202 } 203 /* 204 * Commit to requested usage so driver can see the flags. 205 */ 206 key->wk_flags = (uint16_t)flags; 207 208 /* 209 * Ask the driver for a key index if we don't have one. 210 * Note that entries in the global key table always have 211 * an index; this means it's safe to call this routine 212 * for these entries just to setup the reference to the 213 * cipher template. Note also that when using software 214 * crypto we also call the driver to give us a key index. 215 */ 216 if (key->wk_keyix == IEEE80211_KEYIX_NONE) { 217 if (!DEV_KEY_ALLOC(ic, key, &keyix, &rxkeyix)) { 218 /* 219 * Driver has no room; fallback to doing crypto 220 * in the host. We change the flags and start the 221 * procedure over. If we get back here then there's 222 * no hope and we bail. Note that this can leave 223 * the key in a inconsistent state if the caller 224 * continues to use it. 225 */ 226 if ((key->wk_flags & IEEE80211_KEY_SWCRYPT) == 0) { 227 ieee80211_dbg(IEEE80211_MSG_CRYPTO, 228 "crypto_setkey: " 229 "no h/w resources for cipher %s, " 230 "falling back to s/w\n", cip->ic_name); 231 oflags = key->wk_flags; 232 flags |= IEEE80211_KEY_SWCRYPT; 233 if (cipher == IEEE80211_CIPHER_TKIP) 234 flags |= IEEE80211_KEY_SWMIC; 235 goto again; 236 } 237 ieee80211_dbg(IEEE80211_MSG_CRYPTO, "crypto_setkey: " 238 "unable to setup cipher %s\n", cip->ic_name); 239 return (0); 240 } 241 key->wk_keyix = keyix; 242 key->wk_rxkeyix = rxkeyix; 243 } 244 return (1); 245 } 246 247 /* 248 * Remove the key (no locking, for internal use). 249 */ 250 static int 251 ieee80211_crypto_delkey_locked(ieee80211com_t *ic, struct ieee80211_key *key) 252 { 253 uint16_t keyix; 254 255 ASSERT(key->wk_cipher != NULL); 256 257 keyix = key->wk_keyix; 258 if (keyix != IEEE80211_KEYIX_NONE) { 259 /* 260 * Remove hardware entry. 261 */ 262 if (!DEV_KEY_DELETE(ic, key)) { 263 ieee80211_dbg(IEEE80211_MSG_CRYPTO, 264 "ieee80211_crypto_delkey_locked: ", 265 "driverdeletes key %u failed\n", keyix); 266 } 267 } 268 CIPHER_DETACH(key); 269 bzero(key, sizeof (struct ieee80211_key)); 270 /* NB: cannot depend on key index to decide this */ 271 ieee80211_crypto_resetkey(ic, key, IEEE80211_KEYIX_NONE); 272 return (1); 273 } 274 275 /* 276 * Remove the specified key. 277 */ 278 int 279 ieee80211_crypto_delkey(ieee80211com_t *ic, struct ieee80211_key *key) 280 { 281 int status; 282 283 KEY_UPDATE_BEGIN(ic); 284 status = ieee80211_crypto_delkey_locked(ic, key); 285 KEY_UPDATE_END(ic); 286 return (status); 287 } 288 289 /* 290 * Clear the global key table. 291 */ 292 static void 293 ieee80211_crypto_delglobalkeys(ieee80211com_t *ic) 294 { 295 int i; 296 297 KEY_UPDATE_BEGIN(ic); 298 for (i = 0; i < IEEE80211_WEP_NKID; i++) 299 (void) ieee80211_crypto_delkey_locked(ic, &ic->ic_nw_keys[i]); 300 KEY_UPDATE_END(ic); 301 } 302 303 /* 304 * Set the contents of the specified key. 305 * 306 * Locking must be handled by the caller using: 307 * ieee80211_key_update_begin(ic); 308 * ieee80211_key_update_end(ic); 309 */ 310 int 311 ieee80211_crypto_setkey(ieee80211com_t *ic, struct ieee80211_key *key, 312 const uint8_t *macaddr) 313 { 314 const struct ieee80211_cipher *cip = key->wk_cipher; 315 316 ASSERT(cip != NULL); 317 318 ieee80211_dbg(IEEE80211_MSG_CRYPTO, "ieee80211_crypto_setkey: " 319 "%s keyix %u flags 0x%x mac %s len %u\n", 320 cip->ic_name, key->wk_keyix, key->wk_flags, 321 ieee80211_macaddr_sprintf(macaddr), key->wk_keylen); 322 323 /* 324 * Give cipher a chance to validate key contents. 325 * should happen before modifying state. 326 */ 327 if (cip->ic_setkey(key) == 0) { 328 ieee80211_dbg(IEEE80211_MSG_CRYPTO, "ieee80211_crypto_setkey: " 329 "cipher %s rejected key index %u len %u flags 0x%x\n", 330 cip->ic_name, key->wk_keyix, key->wk_keylen, 331 key->wk_flags); 332 return (0); 333 } 334 if (key->wk_keyix == IEEE80211_KEYIX_NONE) { 335 ieee80211_dbg(IEEE80211_MSG_CRYPTO, "ieee80211_crypto_setkey: " 336 "no key index; should not happen!\n"); 337 return (0); 338 } 339 return (DEV_KEY_SET(ic, key, macaddr)); 340 } 341 342 /* 343 * Return the transmit key to use in sending a frame. 344 */ 345 struct ieee80211_key * 346 ieee80211_crypto_getkey(ieee80211com_t *ic) 347 { 348 if (ic->ic_def_txkey == IEEE80211_KEYIX_NONE || 349 KEY_UNDEFINED(ic->ic_nw_keys[ic->ic_def_txkey])) 350 return (NULL); 351 return (&ic->ic_nw_keys[ic->ic_def_txkey]); 352 } 353 354 uint8_t 355 ieee80211_crypto_getciphertype(ieee80211com_t *ic) 356 { 357 struct ieee80211_key *key; 358 uint32_t cipher; 359 static const uint8_t ciphermap[] = { 360 WIFI_SEC_WEP, /* IEEE80211_CIPHER_WEP */ 361 WIFI_SEC_WPA, /* IEEE80211_CIPHER_TKIP */ 362 (uint8_t)-1, /* IEEE80211_CIPHER_AES_OCB */ 363 WIFI_SEC_WPA, /* IEEE80211_CIPHER_AES_CCM */ 364 (uint8_t)-1, /* IEEE80211_CIPHER_CKIP */ 365 WIFI_SEC_NONE, /* IEEE80211_CIPHER_NONE */ 366 }; 367 368 if ((ic->ic_flags & IEEE80211_F_PRIVACY) == 0) 369 return (WIFI_SEC_NONE); 370 371 key = ieee80211_crypto_getkey(ic); 372 if (key == NULL) 373 return (WIFI_SEC_NONE); 374 375 cipher = key->wk_cipher->ic_cipher; 376 ASSERT(cipher < IEEE80211_N(ciphermap)); 377 return (ciphermap[cipher]); 378 } 379 380 /* 381 * Add privacy headers appropriate for the specified key. 382 */ 383 struct ieee80211_key * 384 ieee80211_crypto_encap(ieee80211com_t *ic, mblk_t *mp) 385 { 386 struct ieee80211_key *k; 387 const struct ieee80211_cipher *cip; 388 uint8_t keyix; 389 390 if (ic->ic_def_txkey == IEEE80211_KEYIX_NONE) { 391 ieee80211_dbg(IEEE80211_MSG_CRYPTO, 392 "ieee80211_crypto_encap: %s", 393 " No default xmit key for frame\n"); 394 return (NULL); 395 } 396 keyix = ic->ic_def_txkey; 397 k = &ic->ic_nw_keys[ic->ic_def_txkey]; 398 cip = k->wk_cipher; 399 return (cip->ic_encap(k, mp, keyix<<6) ? k : NULL); 400 } 401 402 /* 403 * Validate and strip privacy headers (and trailer) for a 404 * received frame that has the WEP/Privacy bit set. 405 */ 406 struct ieee80211_key * 407 ieee80211_crypto_decap(ieee80211com_t *ic, mblk_t *mp, int hdrlen) 408 { 409 struct ieee80211_key *k; 410 const struct ieee80211_cipher *cip; 411 uint8_t *ivp; 412 uint8_t keyid; 413 414 /* NB: this minimum size data frame could be bigger */ 415 if ((mp->b_wptr - mp->b_rptr) < IEEE80211_WEP_MINLEN) { 416 ieee80211_dbg(IEEE80211_MSG_CRYPTO, "ieee80211_crypto_decap:" 417 " WEP data frame too short, len %u\n", 418 mp->b_wptr - mp->b_rptr); 419 return (NULL); 420 } 421 /* 422 * Locate the key. If unicast and there is no unicast 423 * key then we fall back to the key id in the header. 424 * This assumes unicast keys are only configured when 425 * the key id in the header is meaningless (typically 0). 426 */ 427 ivp = mp->b_rptr + hdrlen; 428 keyid = ivp[IEEE80211_WEP_IVLEN]; 429 k = &ic->ic_nw_keys[keyid >> 6]; 430 431 /* check to avoid panic when wep is on but key is not set */ 432 if (k->wk_cipher == &ieee80211_cipher_none || 433 k->wk_cipher == NULL) 434 return (NULL); 435 436 cip = k->wk_cipher; 437 return ((cip->ic_decap)(k, mp, hdrlen) ? k : NULL); 438 } 439 440 441 /* 442 * Setup crypto support. 443 */ 444 void 445 ieee80211_crypto_attach(ieee80211com_t *ic) 446 { 447 struct ieee80211_crypto_state *cs = &ic->ic_crypto; 448 int i; 449 450 /* NB: we assume everything is pre-zero'd */ 451 cs->cs_def_txkey = IEEE80211_KEYIX_NONE; 452 for (i = 0; i < IEEE80211_WEP_NKID; i++) { 453 ieee80211_crypto_resetkey(ic, &cs->cs_nw_keys[i], 454 IEEE80211_KEYIX_NONE); 455 } 456 457 /* 458 * Initialize the driver key support routines to noop entries. 459 * This is useful especially for the cipher test modules. 460 */ 461 cs->cs_key_alloc = nulldev_key_alloc; 462 cs->cs_key_set = nulldev_key_set; 463 cs->cs_key_delete = nulldev_key_delete; 464 cs->cs_key_update_begin = nulldev_key_update; 465 cs->cs_key_update_end = nulldev_key_update; 466 467 ieee80211_crypto_register(&wep); 468 ieee80211_crypto_register(&tkip); 469 ieee80211_crypto_register(&ccmp); 470 } 471 472 /* 473 * Teardown crypto support. 474 */ 475 void 476 ieee80211_crypto_detach(ieee80211com_t *ic) 477 { 478 ieee80211_crypto_delglobalkeys(ic); 479 480 ieee80211_crypto_unregister(&wep); 481 ieee80211_crypto_unregister(&tkip); 482 ieee80211_crypto_unregister(&ccmp); 483 } 484 485 /* 486 * Register a crypto cipher module. 487 */ 488 void 489 ieee80211_crypto_register(const struct ieee80211_cipher *cip) 490 { 491 if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) { 492 ieee80211_err("ieee80211_crypto_register: " 493 "cipher %s has an invalid cipher index %u\n", 494 cip->ic_name, cip->ic_cipher); 495 return; 496 } 497 if (ciphers[cip->ic_cipher] != NULL && ciphers[cip->ic_cipher] != cip) { 498 ieee80211_err("ieee80211_crypto_register: " 499 "cipher %s registered with a different template\n", 500 cip->ic_name); 501 return; 502 } 503 ciphers[cip->ic_cipher] = cip; 504 } 505 506 /* 507 * Unregister a crypto cipher module. 508 */ 509 void 510 ieee80211_crypto_unregister(const struct ieee80211_cipher *cip) 511 { 512 if (cip->ic_cipher >= IEEE80211_CIPHER_MAX) { 513 ieee80211_err("ieee80211_crypto_unregister: " 514 "cipher %s has an invalid cipher index %u\n", 515 cip->ic_name, cip->ic_cipher); 516 return; 517 } 518 if (ciphers[cip->ic_cipher] != NULL && ciphers[cip->ic_cipher] != cip) { 519 ieee80211_err("ieee80211_crypto_unregister: " 520 "cipher %s registered with a different template\n", 521 cip->ic_name); 522 return; 523 } 524 /* NB: don't complain about not being registered */ 525 ciphers[cip->ic_cipher] = NULL; 526 } 527