| 1 | /*- |
| 2 | * Copyright (c) 2002-2005 Sam Leffler, Errno Consulting |
| 3 | * All rights reserved. |
| 4 | * |
| 5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that the following conditions |
| 7 | * are met: |
| 8 | * 1. Redistributions of source code must retain the above copyright |
| 9 | * notice, this list of conditions and the following disclaimer. |
| 10 | * 2. Redistributions in binary form must reproduce the above copyright |
| 11 | * notice, this list of conditions and the following disclaimer in the |
| 12 | * documentation and/or other materials provided with the distribution. |
| 13 | * 3. The name of the author may not be used to endorse or promote products |
| 14 | * derived from this software without specific prior written permission. |
| 15 | * |
| 16 | * Alternatively, this software may be distributed under the terms of the |
| 17 | * GNU General Public License ("GPL") version 2 as published by the Free |
| 18 | * Software Foundation. |
| 19 | * |
| 20 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| 21 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| 22 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| 23 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| 24 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| 25 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 26 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 27 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 28 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| 29 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 30 | */ |
| 31 | |
| 32 | #include <sys/cdefs.h> |
| 33 | #ifdef __FreeBSD__ |
| 34 | __FBSDID("$FreeBSD: src/sys/net80211/ieee80211_crypto_ccmp.c,v 1.7 2005/07/11 03:06:23 sam Exp $" ); |
| 35 | #endif |
| 36 | #ifdef __NetBSD__ |
| 37 | __KERNEL_RCSID(0, "$NetBSD: ieee80211_crypto_ccmp.c,v 1.11 2014/10/18 08:33:29 snj Exp $" ); |
| 38 | #endif |
| 39 | |
| 40 | /* |
| 41 | * IEEE 802.11i AES-CCMP crypto support. |
| 42 | * |
| 43 | * Part of this module is derived from similar code in the Host |
| 44 | * AP driver. The code is used with the consent of the author and |
| 45 | * its license is included below. |
| 46 | */ |
| 47 | #include <sys/param.h> |
| 48 | #include <sys/systm.h> |
| 49 | #include <sys/mbuf.h> |
| 50 | #include <sys/malloc.h> |
| 51 | #include <sys/kernel.h> |
| 52 | |
| 53 | #include <sys/socket.h> |
| 54 | |
| 55 | #include <net/if.h> |
| 56 | #include <net/if_ether.h> |
| 57 | #include <net/if_media.h> |
| 58 | |
| 59 | #include <net80211/ieee80211_var.h> |
| 60 | |
| 61 | #include <crypto/rijndael/rijndael.h> |
| 62 | |
| 63 | #define AES_BLOCK_LEN 16 |
| 64 | |
| 65 | struct ccmp_ctx { |
| 66 | struct ieee80211com *cc_ic; /* for diagnostics */ |
| 67 | rijndael_ctx cc_aes; |
| 68 | }; |
| 69 | |
| 70 | static void *ccmp_attach(struct ieee80211com *, struct ieee80211_key *); |
| 71 | static void ccmp_detach(struct ieee80211_key *); |
| 72 | static int ccmp_setkey(struct ieee80211_key *); |
| 73 | static int ccmp_encap(struct ieee80211_key *k, struct mbuf *, u_int8_t keyid); |
| 74 | static int ccmp_decap(struct ieee80211_key *, struct mbuf *, int); |
| 75 | static int ccmp_enmic(struct ieee80211_key *, struct mbuf *, int); |
| 76 | static int ccmp_demic(struct ieee80211_key *, struct mbuf *, int); |
| 77 | |
| 78 | const struct ieee80211_cipher ieee80211_cipher_ccmp = { |
| 79 | .ic_name = "AES-CCM" , |
| 80 | .ic_cipher = IEEE80211_CIPHER_AES_CCM, |
| 81 | .ic_header = IEEE80211_WEP_IVLEN + IEEE80211_WEP_KIDLEN + |
| 82 | IEEE80211_WEP_EXTIVLEN, |
| 83 | .ic_trailer = IEEE80211_WEP_MICLEN, |
| 84 | .ic_miclen = 0, |
| 85 | .ic_attach = ccmp_attach, |
| 86 | .ic_detach = ccmp_detach, |
| 87 | .ic_setkey = ccmp_setkey, |
| 88 | .ic_encap = ccmp_encap, |
| 89 | .ic_decap = ccmp_decap, |
| 90 | .ic_enmic = ccmp_enmic, |
| 91 | .ic_demic = ccmp_demic, |
| 92 | }; |
| 93 | |
| 94 | #define ccmp ieee80211_cipher_ccmp |
| 95 | |
| 96 | static int ccmp_encrypt(struct ieee80211_key *, struct mbuf *, int hdrlen); |
| 97 | static int ccmp_decrypt(struct ieee80211_key *, u_int64_t pn, |
| 98 | struct mbuf *, int hdrlen); |
| 99 | |
| 100 | static void * |
| 101 | ccmp_attach(struct ieee80211com *ic, struct ieee80211_key *k) |
| 102 | { |
| 103 | struct ccmp_ctx *ctx; |
| 104 | |
| 105 | ctx = malloc(sizeof(struct ccmp_ctx), |
| 106 | M_DEVBUF, M_NOWAIT | M_ZERO); |
| 107 | if (ctx == NULL) { |
| 108 | ic->ic_stats.is_crypto_nomem++; |
| 109 | return NULL; |
| 110 | } |
| 111 | ctx->cc_ic = ic; |
| 112 | return ctx; |
| 113 | } |
| 114 | |
| 115 | static void |
| 116 | ccmp_detach(struct ieee80211_key *k) |
| 117 | { |
| 118 | struct ccmp_ctx *ctx = k->wk_private; |
| 119 | |
| 120 | free(ctx, M_DEVBUF); |
| 121 | } |
| 122 | |
| 123 | static int |
| 124 | ccmp_setkey(struct ieee80211_key *k) |
| 125 | { |
| 126 | struct ccmp_ctx *ctx = k->wk_private; |
| 127 | |
| 128 | if (k->wk_keylen != (128/NBBY)) { |
| 129 | IEEE80211_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO, |
| 130 | "%s: Invalid key length %u, expecting %u\n" , |
| 131 | __func__, k->wk_keylen, 128/NBBY); |
| 132 | return 0; |
| 133 | } |
| 134 | if (k->wk_flags & IEEE80211_KEY_SWCRYPT) |
| 135 | rijndael_set_key(&ctx->cc_aes, k->wk_key, k->wk_keylen*NBBY); |
| 136 | return 1; |
| 137 | } |
| 138 | |
| 139 | /* |
| 140 | * Add privacy headers appropriate for the specified key. |
| 141 | */ |
| 142 | static int |
| 143 | ccmp_encap(struct ieee80211_key *k, struct mbuf *m, u_int8_t keyid) |
| 144 | { |
| 145 | struct ccmp_ctx *ctx = k->wk_private; |
| 146 | struct ieee80211com *ic = ctx->cc_ic; |
| 147 | u_int8_t *ivp; |
| 148 | int hdrlen; |
| 149 | |
| 150 | hdrlen = ieee80211_hdrspace(ic, mtod(m, void *)); |
| 151 | |
| 152 | /* |
| 153 | * Copy down 802.11 header and add the IV, KeyID, and ExtIV. |
| 154 | */ |
| 155 | M_PREPEND(m, ccmp.ic_header, M_NOWAIT); |
| 156 | if (m == NULL) |
| 157 | return 0; |
| 158 | ivp = mtod(m, u_int8_t *); |
| 159 | ovbcopy(ivp + ccmp.ic_header, ivp, hdrlen); |
| 160 | ivp += hdrlen; |
| 161 | |
| 162 | k->wk_keytsc++; /* XXX wrap at 48 bits */ |
| 163 | ivp[0] = k->wk_keytsc >> 0; /* PN0 */ |
| 164 | ivp[1] = k->wk_keytsc >> 8; /* PN1 */ |
| 165 | ivp[2] = 0; /* Reserved */ |
| 166 | ivp[3] = keyid | IEEE80211_WEP_EXTIV; /* KeyID | ExtID */ |
| 167 | ivp[4] = k->wk_keytsc >> 16; /* PN2 */ |
| 168 | ivp[5] = k->wk_keytsc >> 24; /* PN3 */ |
| 169 | ivp[6] = k->wk_keytsc >> 32; /* PN4 */ |
| 170 | ivp[7] = k->wk_keytsc >> 40; /* PN5 */ |
| 171 | |
| 172 | /* |
| 173 | * Finally, do software encrypt if neeed. |
| 174 | */ |
| 175 | if ((k->wk_flags & IEEE80211_KEY_SWCRYPT) && |
| 176 | !ccmp_encrypt(k, m, hdrlen)) |
| 177 | return 0; |
| 178 | |
| 179 | return 1; |
| 180 | } |
| 181 | |
| 182 | /* |
| 183 | * Add MIC to the frame as needed. |
| 184 | */ |
| 185 | static int |
| 186 | ccmp_enmic(struct ieee80211_key *k, struct mbuf *m, |
| 187 | int force) |
| 188 | { |
| 189 | |
| 190 | return 1; |
| 191 | } |
| 192 | |
| 193 | static __inline uint64_t |
| 194 | READ_6(uint8_t b0, uint8_t b1, uint8_t b2, uint8_t b3, uint8_t b4, uint8_t b5) |
| 195 | { |
| 196 | uint32_t iv32 = (b0 << 0) | (b1 << 8) | (b2 << 16) | (b3 << 24); |
| 197 | uint16_t iv16 = (b4 << 0) | (b5 << 8); |
| 198 | return (((uint64_t)iv16) << 32) | iv32; |
| 199 | } |
| 200 | |
| 201 | /* |
| 202 | * Validate and strip privacy headers (and trailer) for a |
| 203 | * received frame. The specified key should be correct but |
| 204 | * is also verified. |
| 205 | */ |
| 206 | static int |
| 207 | ccmp_decap(struct ieee80211_key *k, struct mbuf *m, int hdrlen) |
| 208 | { |
| 209 | struct ccmp_ctx *ctx = k->wk_private; |
| 210 | struct ieee80211_frame *wh; |
| 211 | uint8_t *ivp; |
| 212 | uint64_t pn; |
| 213 | |
| 214 | /* |
| 215 | * Header should have extended IV and sequence number; |
| 216 | * verify the former and validate the latter. |
| 217 | */ |
| 218 | wh = mtod(m, struct ieee80211_frame *); |
| 219 | ivp = mtod(m, uint8_t *) + hdrlen; |
| 220 | if ((ivp[IEEE80211_WEP_IVLEN] & IEEE80211_WEP_EXTIV) == 0) { |
| 221 | /* |
| 222 | * No extended IV; discard frame. |
| 223 | */ |
| 224 | IEEE80211_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO, |
| 225 | "[%s] Missing ExtIV for AES-CCM cipher\n" , |
| 226 | ether_sprintf(wh->i_addr2)); |
| 227 | ctx->cc_ic->ic_stats.is_rx_ccmpformat++; |
| 228 | return 0; |
| 229 | } |
| 230 | pn = READ_6(ivp[0], ivp[1], ivp[4], ivp[5], ivp[6], ivp[7]); |
| 231 | if (pn <= k->wk_keyrsc) { |
| 232 | /* |
| 233 | * Replay violation. |
| 234 | */ |
| 235 | ieee80211_notify_replay_failure(ctx->cc_ic, wh, k, pn); |
| 236 | ctx->cc_ic->ic_stats.is_rx_ccmpreplay++; |
| 237 | return 0; |
| 238 | } |
| 239 | |
| 240 | /* |
| 241 | * Check if the device handled the decrypt in hardware. |
| 242 | * If so we just strip the header; otherwise we need to |
| 243 | * handle the decrypt in software. Note that for the |
| 244 | * latter we leave the header in place for use in the |
| 245 | * decryption work. |
| 246 | */ |
| 247 | if ((k->wk_flags & IEEE80211_KEY_SWCRYPT) && |
| 248 | !ccmp_decrypt(k, pn, m, hdrlen)) |
| 249 | return 0; |
| 250 | |
| 251 | /* |
| 252 | * Copy up 802.11 header and strip crypto bits. |
| 253 | */ |
| 254 | ovbcopy(mtod(m, void *), mtod(m, u_int8_t *) + ccmp.ic_header, hdrlen); |
| 255 | m_adj(m, ccmp.ic_header); |
| 256 | m_adj(m, -ccmp.ic_trailer); |
| 257 | |
| 258 | /* |
| 259 | * Ok to update rsc now. |
| 260 | */ |
| 261 | k->wk_keyrsc = pn; |
| 262 | |
| 263 | return 1; |
| 264 | } |
| 265 | |
| 266 | /* |
| 267 | * Verify and strip MIC from the frame. |
| 268 | */ |
| 269 | static int |
| 270 | ccmp_demic(struct ieee80211_key *k, struct mbuf *m, |
| 271 | int force) |
| 272 | { |
| 273 | return 1; |
| 274 | } |
| 275 | |
| 276 | static __inline void |
| 277 | xor_block(uint8_t *b, const uint8_t *a, size_t len) |
| 278 | { |
| 279 | int i; |
| 280 | for (i = 0; i < len; i++) |
| 281 | b[i] ^= a[i]; |
| 282 | } |
| 283 | |
| 284 | /* |
| 285 | * Host AP crypt: host-based CCMP encryption implementation for Host AP driver |
| 286 | * |
| 287 | * Copyright (c) 2003-2004, Jouni Malinen <jkmaline@cc.hut.fi> |
| 288 | * |
| 289 | * This program is free software; you can redistribute it and/or modify |
| 290 | * it under the terms of the GNU General Public License version 2 as |
| 291 | * published by the Free Software Foundation. See README and COPYING for |
| 292 | * more details. |
| 293 | * |
| 294 | * Alternatively, this software may be distributed under the terms of BSD |
| 295 | * license. |
| 296 | */ |
| 297 | |
| 298 | static void |
| 299 | ccmp_init_blocks(rijndael_ctx *ctx, struct ieee80211_frame *wh, |
| 300 | u_int64_t pn, size_t dlen, |
| 301 | uint8_t b0[AES_BLOCK_LEN], uint8_t aad[2 * AES_BLOCK_LEN], |
| 302 | uint8_t auth[AES_BLOCK_LEN], uint8_t s0[AES_BLOCK_LEN]) |
| 303 | { |
| 304 | #define IS_4ADDRESS(wh) \ |
| 305 | ((wh->i_fc[1] & IEEE80211_FC1_DIR_MASK) == IEEE80211_FC1_DIR_DSTODS) |
| 306 | #define IS_QOS_DATA(wh) ieee80211_has_qos(wh) |
| 307 | |
| 308 | /* CCM Initial Block: |
| 309 | * Flag (Include authentication header, M=3 (8-octet MIC), |
| 310 | * L=1 (2-octet Dlen)) |
| 311 | * Nonce: 0x00 | A2 | PN |
| 312 | * Dlen */ |
| 313 | b0[0] = 0x59; |
| 314 | /* NB: b0[1] set below */ |
| 315 | IEEE80211_ADDR_COPY(b0 + 2, wh->i_addr2); |
| 316 | b0[8] = pn >> 40; |
| 317 | b0[9] = pn >> 32; |
| 318 | b0[10] = pn >> 24; |
| 319 | b0[11] = pn >> 16; |
| 320 | b0[12] = pn >> 8; |
| 321 | b0[13] = pn >> 0; |
| 322 | b0[14] = (dlen >> 8) & 0xff; |
| 323 | b0[15] = dlen & 0xff; |
| 324 | |
| 325 | /* AAD: |
| 326 | * FC with bits 4..6 and 11..13 masked to zero; 14 is always one |
| 327 | * A1 | A2 | A3 |
| 328 | * SC with bits 4..15 (seq#) masked to zero |
| 329 | * A4 (if present) |
| 330 | * QC (if present) |
| 331 | */ |
| 332 | aad[0] = 0; /* AAD length >> 8 */ |
| 333 | /* NB: aad[1] set below */ |
| 334 | aad[2] = wh->i_fc[0] & 0x8f; /* XXX magic #s */ |
| 335 | aad[3] = wh->i_fc[1] & 0xc7; /* XXX magic #s */ |
| 336 | /* NB: we know 3 addresses are contiguous */ |
| 337 | memcpy(aad + 4, wh->i_addr1, 3 * IEEE80211_ADDR_LEN); |
| 338 | aad[22] = wh->i_seq[0] & IEEE80211_SEQ_FRAG_MASK; |
| 339 | aad[23] = 0; /* all bits masked */ |
| 340 | /* |
| 341 | * Construct variable-length portion of AAD based |
| 342 | * on whether this is a 4-address frame/QOS frame. |
| 343 | * We always zero-pad to 32 bytes before running it |
| 344 | * through the cipher. |
| 345 | * |
| 346 | * We also fill in the priority bits of the CCM |
| 347 | * initial block as we know whether or not we have |
| 348 | * a QOS frame. |
| 349 | */ |
| 350 | if (IS_4ADDRESS(wh)) { |
| 351 | IEEE80211_ADDR_COPY(aad + 24, |
| 352 | ((struct ieee80211_frame_addr4 *)wh)->i_addr4); |
| 353 | if (IS_QOS_DATA(wh)) { |
| 354 | struct ieee80211_qosframe_addr4 *qwh4 = |
| 355 | (struct ieee80211_qosframe_addr4 *) wh; |
| 356 | aad[30] = qwh4->i_qos[0] & 0x0f;/* just priority bits */ |
| 357 | aad[31] = 0; |
| 358 | b0[1] = aad[30]; |
| 359 | aad[1] = 22 + IEEE80211_ADDR_LEN + 2; |
| 360 | } else { |
| 361 | *(u_int16_t *)&aad[30] = 0; |
| 362 | b0[1] = 0; |
| 363 | aad[1] = 22 + IEEE80211_ADDR_LEN; |
| 364 | } |
| 365 | } else { |
| 366 | if (IS_QOS_DATA(wh)) { |
| 367 | struct ieee80211_qosframe *qwh = |
| 368 | (struct ieee80211_qosframe*) wh; |
| 369 | aad[24] = qwh->i_qos[0] & 0x0f; /* just priority bits */ |
| 370 | aad[25] = 0; |
| 371 | b0[1] = aad[24]; |
| 372 | aad[1] = 22 + 2; |
| 373 | } else { |
| 374 | *(u_int16_t *)&aad[24] = 0; |
| 375 | b0[1] = 0; |
| 376 | aad[1] = 22; |
| 377 | } |
| 378 | *(u_int16_t *)&aad[26] = 0; |
| 379 | *(u_int32_t *)&aad[28] = 0; |
| 380 | } |
| 381 | |
| 382 | /* Start with the first block and AAD */ |
| 383 | rijndael_encrypt(ctx, b0, auth); |
| 384 | xor_block(auth, aad, AES_BLOCK_LEN); |
| 385 | rijndael_encrypt(ctx, auth, auth); |
| 386 | xor_block(auth, &aad[AES_BLOCK_LEN], AES_BLOCK_LEN); |
| 387 | rijndael_encrypt(ctx, auth, auth); |
| 388 | b0[0] &= 0x07; |
| 389 | b0[14] = b0[15] = 0; |
| 390 | rijndael_encrypt(ctx, b0, s0); |
| 391 | #undef IS_QOS_DATA |
| 392 | #undef IS_4ADDRESS |
| 393 | } |
| 394 | |
| 395 | #define CCMP_ENCRYPT(_i, _b, _b0, _pos, _e, _len) do { \ |
| 396 | /* Authentication */ \ |
| 397 | xor_block(_b, _pos, _len); \ |
| 398 | rijndael_encrypt(&ctx->cc_aes, _b, _b); \ |
| 399 | /* Encryption, with counter */ \ |
| 400 | _b0[14] = (_i >> 8) & 0xff; \ |
| 401 | _b0[15] = _i & 0xff; \ |
| 402 | rijndael_encrypt(&ctx->cc_aes, _b0, _e); \ |
| 403 | xor_block(_pos, _e, _len); \ |
| 404 | } while (0) |
| 405 | |
| 406 | static int |
| 407 | ccmp_encrypt(struct ieee80211_key *key, struct mbuf *m0, int hdrlen) |
| 408 | { |
| 409 | struct ccmp_ctx *ctx = key->wk_private; |
| 410 | struct ieee80211_frame *wh; |
| 411 | struct mbuf *m = m0; |
| 412 | int data_len, i, space; |
| 413 | uint8_t aad[2 * AES_BLOCK_LEN], b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], |
| 414 | e[AES_BLOCK_LEN], s0[AES_BLOCK_LEN]; |
| 415 | uint8_t *pos; |
| 416 | |
| 417 | ctx->cc_ic->ic_stats.is_crypto_ccmp++; |
| 418 | |
| 419 | wh = mtod(m, struct ieee80211_frame *); |
| 420 | data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header); |
| 421 | ccmp_init_blocks(&ctx->cc_aes, wh, key->wk_keytsc, |
| 422 | data_len, b0, aad, b, s0); |
| 423 | |
| 424 | i = 1; |
| 425 | pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header; |
| 426 | /* NB: assumes header is entirely in first mbuf */ |
| 427 | space = m->m_len - (hdrlen + ccmp.ic_header); |
| 428 | for (;;) { |
| 429 | if (space > data_len) |
| 430 | space = data_len; |
| 431 | /* |
| 432 | * Do full blocks. |
| 433 | */ |
| 434 | while (space >= AES_BLOCK_LEN) { |
| 435 | CCMP_ENCRYPT(i, b, b0, pos, e, AES_BLOCK_LEN); |
| 436 | pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN; |
| 437 | data_len -= AES_BLOCK_LEN; |
| 438 | i++; |
| 439 | } |
| 440 | if (data_len <= 0) /* no more data */ |
| 441 | break; |
| 442 | m = m->m_next; |
| 443 | if (m == NULL) { /* last buffer */ |
| 444 | if (space != 0) { |
| 445 | /* |
| 446 | * Short last block. |
| 447 | */ |
| 448 | CCMP_ENCRYPT(i, b, b0, pos, e, space); |
| 449 | } |
| 450 | break; |
| 451 | } |
| 452 | if (space != 0) { |
| 453 | uint8_t *pos_next; |
| 454 | int space_next; |
| 455 | int len, dl, sp; |
| 456 | struct mbuf *n; |
| 457 | |
| 458 | /* |
| 459 | * Block straddles one or more mbufs, gather data |
| 460 | * into the block buffer b, apply the cipher, then |
| 461 | * scatter the results back into the mbuf chain. |
| 462 | * The buffer will automatically get space bytes |
| 463 | * of data at offset 0 copied in+out by the |
| 464 | * CCMP_ENCRYPT request so we must take care of |
| 465 | * the remaining data. |
| 466 | */ |
| 467 | n = m; |
| 468 | dl = data_len; |
| 469 | sp = space; |
| 470 | for (;;) { |
| 471 | pos_next = mtod(n, uint8_t *); |
| 472 | len = min(dl, AES_BLOCK_LEN); |
| 473 | space_next = len > sp ? len - sp : 0; |
| 474 | if (n->m_len >= space_next) { |
| 475 | /* |
| 476 | * This mbuf has enough data; just grab |
| 477 | * what we need and stop. |
| 478 | */ |
| 479 | xor_block(b+sp, pos_next, space_next); |
| 480 | break; |
| 481 | } |
| 482 | /* |
| 483 | * This mbuf's contents are insufficient, |
| 484 | * take 'em all and prepare to advance to |
| 485 | * the next mbuf. |
| 486 | */ |
| 487 | xor_block(b+sp, pos_next, n->m_len); |
| 488 | sp += n->m_len, dl -= n->m_len; |
| 489 | n = n->m_next; |
| 490 | if (n == NULL) |
| 491 | break; |
| 492 | } |
| 493 | |
| 494 | CCMP_ENCRYPT(i, b, b0, pos, e, space); |
| 495 | |
| 496 | /* NB: just like above, but scatter data to mbufs */ |
| 497 | dl = data_len; |
| 498 | sp = space; |
| 499 | for (;;) { |
| 500 | pos_next = mtod(m, uint8_t *); |
| 501 | len = min(dl, AES_BLOCK_LEN); |
| 502 | space_next = len > sp ? len - sp : 0; |
| 503 | if (m->m_len >= space_next) { |
| 504 | xor_block(pos_next, e+sp, space_next); |
| 505 | break; |
| 506 | } |
| 507 | xor_block(pos_next, e+sp, m->m_len); |
| 508 | sp += m->m_len, dl -= m->m_len; |
| 509 | m = m->m_next; |
| 510 | if (m == NULL) |
| 511 | goto done; |
| 512 | } |
| 513 | /* |
| 514 | * Do bookkeeping. m now points to the last mbuf |
| 515 | * we grabbed data from. We know we consumed a |
| 516 | * full block of data as otherwise we'd have hit |
| 517 | * the end of the mbuf chain, so deduct from data_len. |
| 518 | * Otherwise advance the block number (i) and setup |
| 519 | * pos+space to reflect contents of the new mbuf. |
| 520 | */ |
| 521 | data_len -= AES_BLOCK_LEN; |
| 522 | i++; |
| 523 | pos = pos_next + space_next; |
| 524 | space = m->m_len - space_next; |
| 525 | } else { |
| 526 | /* |
| 527 | * Setup for next buffer. |
| 528 | */ |
| 529 | pos = mtod(m, uint8_t *); |
| 530 | space = m->m_len; |
| 531 | } |
| 532 | } |
| 533 | done: |
| 534 | /* tack on MIC */ |
| 535 | xor_block(b, s0, ccmp.ic_trailer); |
| 536 | return m_append(m0, ccmp.ic_trailer, b); |
| 537 | } |
| 538 | #undef CCMP_ENCRYPT |
| 539 | |
| 540 | #define CCMP_DECRYPT(_i, _b, _b0, _pos, _a, _len) do { \ |
| 541 | /* Decrypt, with counter */ \ |
| 542 | _b0[14] = (_i >> 8) & 0xff; \ |
| 543 | _b0[15] = _i & 0xff; \ |
| 544 | rijndael_encrypt(&ctx->cc_aes, _b0, _b); \ |
| 545 | xor_block(_pos, _b, _len); \ |
| 546 | /* Authentication */ \ |
| 547 | xor_block(_a, _pos, _len); \ |
| 548 | rijndael_encrypt(&ctx->cc_aes, _a, _a); \ |
| 549 | } while (0) |
| 550 | |
| 551 | static int |
| 552 | ccmp_decrypt(struct ieee80211_key *key, u_int64_t pn, struct mbuf *m, int hdrlen) |
| 553 | { |
| 554 | struct ccmp_ctx *ctx = key->wk_private; |
| 555 | struct ieee80211_frame *wh; |
| 556 | uint8_t aad[2 * AES_BLOCK_LEN]; |
| 557 | uint8_t b0[AES_BLOCK_LEN], b[AES_BLOCK_LEN], a[AES_BLOCK_LEN]; |
| 558 | uint8_t mic[AES_BLOCK_LEN]; |
| 559 | size_t data_len; |
| 560 | int i; |
| 561 | uint8_t *pos; |
| 562 | u_int space; |
| 563 | |
| 564 | ctx->cc_ic->ic_stats.is_crypto_ccmp++; |
| 565 | |
| 566 | wh = mtod(m, struct ieee80211_frame *); |
| 567 | data_len = m->m_pkthdr.len - (hdrlen + ccmp.ic_header + ccmp.ic_trailer); |
| 568 | ccmp_init_blocks(&ctx->cc_aes, wh, pn, data_len, b0, aad, a, b); |
| 569 | m_copydata(m, m->m_pkthdr.len - ccmp.ic_trailer, ccmp.ic_trailer, mic); |
| 570 | xor_block(mic, b, ccmp.ic_trailer); |
| 571 | |
| 572 | i = 1; |
| 573 | pos = mtod(m, uint8_t *) + hdrlen + ccmp.ic_header; |
| 574 | space = m->m_len - (hdrlen + ccmp.ic_header); |
| 575 | for (;;) { |
| 576 | if (space > data_len) |
| 577 | space = data_len; |
| 578 | while (space >= AES_BLOCK_LEN) { |
| 579 | CCMP_DECRYPT(i, b, b0, pos, a, AES_BLOCK_LEN); |
| 580 | pos += AES_BLOCK_LEN, space -= AES_BLOCK_LEN; |
| 581 | data_len -= AES_BLOCK_LEN; |
| 582 | i++; |
| 583 | } |
| 584 | if (data_len <= 0) /* no more data */ |
| 585 | break; |
| 586 | m = m->m_next; |
| 587 | if (m == NULL) { /* last buffer */ |
| 588 | if (space != 0) /* short last block */ |
| 589 | CCMP_DECRYPT(i, b, b0, pos, a, space); |
| 590 | break; |
| 591 | } |
| 592 | if (space != 0) { |
| 593 | uint8_t *pos_next; |
| 594 | u_int space_next; |
| 595 | u_int len; |
| 596 | |
| 597 | /* |
| 598 | * Block straddles buffers, split references. We |
| 599 | * do not handle splits that require >2 buffers |
| 600 | * since rx'd frames are never badly fragmented |
| 601 | * because drivers typically recv in clusters. |
| 602 | */ |
| 603 | pos_next = mtod(m, uint8_t *); |
| 604 | len = min(data_len, AES_BLOCK_LEN); |
| 605 | space_next = len > space ? len - space : 0; |
| 606 | IASSERT(m->m_len >= space_next, |
| 607 | ("not enough data in following buffer, " |
| 608 | "m_len %u need %u\n" , m->m_len, space_next)); |
| 609 | |
| 610 | xor_block(b+space, pos_next, space_next); |
| 611 | CCMP_DECRYPT(i, b, b0, pos, a, space); |
| 612 | xor_block(pos_next, b+space, space_next); |
| 613 | data_len -= len; |
| 614 | i++; |
| 615 | |
| 616 | pos = pos_next + space_next; |
| 617 | space = m->m_len - space_next; |
| 618 | } else { |
| 619 | /* |
| 620 | * Setup for next buffer. |
| 621 | */ |
| 622 | pos = mtod(m, uint8_t *); |
| 623 | space = m->m_len; |
| 624 | } |
| 625 | } |
| 626 | if (memcmp(mic, a, ccmp.ic_trailer) != 0) { |
| 627 | IEEE80211_DPRINTF(ctx->cc_ic, IEEE80211_MSG_CRYPTO, |
| 628 | "[%s] AES-CCM decrypt failed; MIC mismatch\n" , |
| 629 | ether_sprintf(wh->i_addr2)); |
| 630 | ctx->cc_ic->ic_stats.is_rx_ccmpmic++; |
| 631 | return 0; |
| 632 | } |
| 633 | return 1; |
| 634 | } |
| 635 | #undef CCMP_DECRYPT |
| 636 | |
| 637 | IEEE80211_CRYPTO_SETUP(ccmp_register) |
| 638 | { |
| 639 | ieee80211_crypto_register(&ccmp); |
| 640 | } |
| 641 | |