1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2008 Isilon Inc http://www.isilon.com/ 5 * Authors: Doug Rabson <dfr@rabson.org> 6 * Developed with Red Inc: Alfred Perlstein <alfred@freebsd.org> 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #include <sys/cdefs.h> 31 __FBSDID("$FreeBSD$"); 32 33 #include <sys/param.h> 34 #include <sys/lock.h> 35 #include <sys/malloc.h> 36 #include <sys/mutex.h> 37 #include <sys/kobj.h> 38 #include <sys/mbuf.h> 39 #include <opencrypto/cryptodev.h> 40 41 #include <kgssapi/gssapi.h> 42 #include <kgssapi/gssapi_impl.h> 43 44 #include "kcrypto.h" 45 46 struct aes_state { 47 struct mtx as_lock; 48 crypto_session_t as_session_aes; 49 crypto_session_t as_session_sha1; 50 }; 51 52 static void 53 aes_init(struct krb5_key_state *ks) 54 { 55 struct aes_state *as; 56 57 as = malloc(sizeof(struct aes_state), M_GSSAPI, M_WAITOK|M_ZERO); 58 mtx_init(&as->as_lock, "gss aes lock", NULL, MTX_DEF); 59 ks->ks_priv = as; 60 } 61 62 static void 63 aes_destroy(struct krb5_key_state *ks) 64 { 65 struct aes_state *as = ks->ks_priv; 66 67 if (as->as_session_aes != 0) 68 crypto_freesession(as->as_session_aes); 69 if (as->as_session_sha1 != 0) 70 crypto_freesession(as->as_session_sha1); 71 mtx_destroy(&as->as_lock); 72 free(ks->ks_priv, M_GSSAPI); 73 } 74 75 static void 76 aes_set_key(struct krb5_key_state *ks, const void *in) 77 { 78 void *kp = ks->ks_key; 79 struct aes_state *as = ks->ks_priv; 80 struct cryptoini cri; 81 82 if (kp != in) 83 bcopy(in, kp, ks->ks_class->ec_keylen); 84 85 if (as->as_session_aes != 0) 86 crypto_freesession(as->as_session_aes); 87 if (as->as_session_sha1 != 0) 88 crypto_freesession(as->as_session_sha1); 89 90 /* 91 * We only want the first 96 bits of the HMAC. 92 */ 93 bzero(&cri, sizeof(cri)); 94 cri.cri_alg = CRYPTO_SHA1_HMAC; 95 cri.cri_klen = ks->ks_class->ec_keybits; 96 cri.cri_mlen = 12; 97 cri.cri_key = ks->ks_key; 98 cri.cri_next = NULL; 99 crypto_newsession(&as->as_session_sha1, &cri, 100 CRYPTOCAP_F_HARDWARE | CRYPTOCAP_F_SOFTWARE); 101 102 bzero(&cri, sizeof(cri)); 103 cri.cri_alg = CRYPTO_AES_CBC; 104 cri.cri_klen = ks->ks_class->ec_keybits; 105 cri.cri_mlen = 0; 106 cri.cri_key = ks->ks_key; 107 cri.cri_next = NULL; 108 crypto_newsession(&as->as_session_aes, &cri, 109 CRYPTOCAP_F_HARDWARE | CRYPTOCAP_F_SOFTWARE); 110 } 111 112 static void 113 aes_random_to_key(struct krb5_key_state *ks, const void *in) 114 { 115 116 aes_set_key(ks, in); 117 } 118 119 static int 120 aes_crypto_cb(struct cryptop *crp) 121 { 122 int error; 123 struct aes_state *as = (struct aes_state *) crp->crp_opaque; 124 125 if (crypto_ses2caps(crp->crp_session) & CRYPTOCAP_F_SYNC) 126 return (0); 127 128 error = crp->crp_etype; 129 if (error == EAGAIN) 130 error = crypto_dispatch(crp); 131 mtx_lock(&as->as_lock); 132 if (error || (crp->crp_flags & CRYPTO_F_DONE)) 133 wakeup(crp); 134 mtx_unlock(&as->as_lock); 135 136 return (0); 137 } 138 139 static void 140 aes_encrypt_1(const struct krb5_key_state *ks, int buftype, void *buf, 141 size_t skip, size_t len, void *ivec, int encdec) 142 { 143 struct aes_state *as = ks->ks_priv; 144 struct cryptop *crp; 145 struct cryptodesc *crd; 146 int error; 147 148 crp = crypto_getreq(1); 149 crd = crp->crp_desc; 150 151 crd->crd_skip = skip; 152 crd->crd_len = len; 153 crd->crd_flags = CRD_F_IV_EXPLICIT | CRD_F_IV_PRESENT | encdec; 154 if (ivec) { 155 bcopy(ivec, crd->crd_iv, 16); 156 } else { 157 bzero(crd->crd_iv, 16); 158 } 159 crd->crd_next = NULL; 160 crd->crd_alg = CRYPTO_AES_CBC; 161 162 crp->crp_session = as->as_session_aes; 163 crp->crp_flags = buftype | CRYPTO_F_CBIFSYNC; 164 crp->crp_buf = buf; 165 crp->crp_opaque = (void *) as; 166 crp->crp_callback = aes_crypto_cb; 167 168 error = crypto_dispatch(crp); 169 170 if ((crypto_ses2caps(as->as_session_aes) & CRYPTOCAP_F_SYNC) == 0) { 171 mtx_lock(&as->as_lock); 172 if (!error && !(crp->crp_flags & CRYPTO_F_DONE)) 173 error = msleep(crp, &as->as_lock, 0, "gssaes", 0); 174 mtx_unlock(&as->as_lock); 175 } 176 177 crypto_freereq(crp); 178 } 179 180 static void 181 aes_encrypt(const struct krb5_key_state *ks, struct mbuf *inout, 182 size_t skip, size_t len, void *ivec, size_t ivlen) 183 { 184 size_t blocklen = 16, plen; 185 struct { 186 uint8_t cn_1[16], cn[16]; 187 } last2; 188 int i, off; 189 190 /* 191 * AES encryption with cyphertext stealing: 192 * 193 * CTSencrypt(P[0], ..., P[n], IV, K): 194 * len = length(P[n]) 195 * (C[0], ..., C[n-2], E[n-1]) = 196 * CBCencrypt(P[0], ..., P[n-1], IV, K) 197 * P = pad(P[n], 0, blocksize) 198 * E[n] = CBCencrypt(P, E[n-1], K); 199 * C[n-1] = E[n] 200 * C[n] = E[n-1]{0..len-1} 201 */ 202 plen = len % blocklen; 203 if (len == blocklen) { 204 /* 205 * Note: caller will ensure len >= blocklen. 206 */ 207 aes_encrypt_1(ks, CRYPTO_F_IMBUF, inout, skip, len, ivec, 208 CRD_F_ENCRYPT); 209 } else if (plen == 0) { 210 /* 211 * This is equivalent to CBC mode followed by swapping 212 * the last two blocks. We assume that neither of the 213 * last two blocks cross iov boundaries. 214 */ 215 aes_encrypt_1(ks, CRYPTO_F_IMBUF, inout, skip, len, ivec, 216 CRD_F_ENCRYPT); 217 off = skip + len - 2 * blocklen; 218 m_copydata(inout, off, 2 * blocklen, (void*) &last2); 219 m_copyback(inout, off, blocklen, last2.cn); 220 m_copyback(inout, off + blocklen, blocklen, last2.cn_1); 221 } else { 222 /* 223 * This is the difficult case. We encrypt all but the 224 * last partial block first. We then create a padded 225 * copy of the last block and encrypt that using the 226 * second to last encrypted block as IV. Once we have 227 * the encrypted versions of the last two blocks, we 228 * reshuffle to create the final result. 229 */ 230 aes_encrypt_1(ks, CRYPTO_F_IMBUF, inout, skip, len - plen, 231 ivec, CRD_F_ENCRYPT); 232 233 /* 234 * Copy out the last two blocks, pad the last block 235 * and encrypt it. Rearrange to get the final 236 * result. The cyphertext for cn_1 is in cn. The 237 * cyphertext for cn is the first plen bytes of what 238 * is in cn_1 now. 239 */ 240 off = skip + len - blocklen - plen; 241 m_copydata(inout, off, blocklen + plen, (void*) &last2); 242 for (i = plen; i < blocklen; i++) 243 last2.cn[i] = 0; 244 aes_encrypt_1(ks, 0, last2.cn, 0, blocklen, last2.cn_1, 245 CRD_F_ENCRYPT); 246 m_copyback(inout, off, blocklen, last2.cn); 247 m_copyback(inout, off + blocklen, plen, last2.cn_1); 248 } 249 } 250 251 static void 252 aes_decrypt(const struct krb5_key_state *ks, struct mbuf *inout, 253 size_t skip, size_t len, void *ivec, size_t ivlen) 254 { 255 size_t blocklen = 16, plen; 256 struct { 257 uint8_t cn_1[16], cn[16]; 258 } last2; 259 int i, off, t; 260 261 /* 262 * AES decryption with cyphertext stealing: 263 * 264 * CTSencrypt(C[0], ..., C[n], IV, K): 265 * len = length(C[n]) 266 * E[n] = C[n-1] 267 * X = decrypt(E[n], K) 268 * P[n] = (X ^ C[n]){0..len-1} 269 * E[n-1] = {C[n,0],...,C[n,len-1],X[len],...,X[blocksize-1]} 270 * (P[0],...,P[n-1]) = CBCdecrypt(C[0],...,C[n-2],E[n-1], IV, K) 271 */ 272 plen = len % blocklen; 273 if (len == blocklen) { 274 /* 275 * Note: caller will ensure len >= blocklen. 276 */ 277 aes_encrypt_1(ks, CRYPTO_F_IMBUF, inout, skip, len, ivec, 0); 278 } else if (plen == 0) { 279 /* 280 * This is equivalent to CBC mode followed by swapping 281 * the last two blocks. 282 */ 283 off = skip + len - 2 * blocklen; 284 m_copydata(inout, off, 2 * blocklen, (void*) &last2); 285 m_copyback(inout, off, blocklen, last2.cn); 286 m_copyback(inout, off + blocklen, blocklen, last2.cn_1); 287 aes_encrypt_1(ks, CRYPTO_F_IMBUF, inout, skip, len, ivec, 0); 288 } else { 289 /* 290 * This is the difficult case. We first decrypt the 291 * second to last block with a zero IV to make X. The 292 * plaintext for the last block is the XOR of X and 293 * the last cyphertext block. 294 * 295 * We derive a new cypher text for the second to last 296 * block by mixing the unused bytes of X with the last 297 * cyphertext block. The result of that can be 298 * decrypted with the rest in CBC mode. 299 */ 300 off = skip + len - plen - blocklen; 301 aes_encrypt_1(ks, CRYPTO_F_IMBUF, inout, off, blocklen, 302 NULL, 0); 303 m_copydata(inout, off, blocklen + plen, (void*) &last2); 304 305 for (i = 0; i < plen; i++) { 306 t = last2.cn[i]; 307 last2.cn[i] ^= last2.cn_1[i]; 308 last2.cn_1[i] = t; 309 } 310 311 m_copyback(inout, off, blocklen + plen, (void*) &last2); 312 aes_encrypt_1(ks, CRYPTO_F_IMBUF, inout, skip, len - plen, 313 ivec, 0); 314 } 315 316 } 317 318 static void 319 aes_checksum(const struct krb5_key_state *ks, int usage, 320 struct mbuf *inout, size_t skip, size_t inlen, size_t outlen) 321 { 322 struct aes_state *as = ks->ks_priv; 323 struct cryptop *crp; 324 struct cryptodesc *crd; 325 int error; 326 327 crp = crypto_getreq(1); 328 crd = crp->crp_desc; 329 330 crd->crd_skip = skip; 331 crd->crd_len = inlen; 332 crd->crd_inject = skip + inlen; 333 crd->crd_flags = 0; 334 crd->crd_next = NULL; 335 crd->crd_alg = CRYPTO_SHA1_HMAC; 336 337 crp->crp_session = as->as_session_sha1; 338 crp->crp_ilen = inlen; 339 crp->crp_olen = 12; 340 crp->crp_etype = 0; 341 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC; 342 crp->crp_buf = (void *) inout; 343 crp->crp_opaque = (void *) as; 344 crp->crp_callback = aes_crypto_cb; 345 346 error = crypto_dispatch(crp); 347 348 if ((crypto_ses2caps(as->as_session_sha1) & CRYPTOCAP_F_SYNC) == 0) { 349 mtx_lock(&as->as_lock); 350 if (!error && !(crp->crp_flags & CRYPTO_F_DONE)) 351 error = msleep(crp, &as->as_lock, 0, "gssaes", 0); 352 mtx_unlock(&as->as_lock); 353 } 354 355 crypto_freereq(crp); 356 } 357 358 struct krb5_encryption_class krb5_aes128_encryption_class = { 359 "aes128-cts-hmac-sha1-96", /* name */ 360 ETYPE_AES128_CTS_HMAC_SHA1_96, /* etype */ 361 EC_DERIVED_KEYS, /* flags */ 362 16, /* blocklen */ 363 1, /* msgblocklen */ 364 12, /* checksumlen */ 365 128, /* keybits */ 366 16, /* keylen */ 367 aes_init, 368 aes_destroy, 369 aes_set_key, 370 aes_random_to_key, 371 aes_encrypt, 372 aes_decrypt, 373 aes_checksum 374 }; 375 376 struct krb5_encryption_class krb5_aes256_encryption_class = { 377 "aes256-cts-hmac-sha1-96", /* name */ 378 ETYPE_AES256_CTS_HMAC_SHA1_96, /* etype */ 379 EC_DERIVED_KEYS, /* flags */ 380 16, /* blocklen */ 381 1, /* msgblocklen */ 382 12, /* checksumlen */ 383 256, /* keybits */ 384 32, /* keylen */ 385 aes_init, 386 aes_destroy, 387 aes_set_key, 388 aes_random_to_key, 389 aes_encrypt, 390 aes_decrypt, 391 aes_checksum 392 }; 393