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 crypto_session_params csp; 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 memset(&csp, 0, sizeof(csp)); 94 csp.csp_mode = CSP_MODE_DIGEST; 95 csp.csp_auth_alg = CRYPTO_SHA1_HMAC; 96 csp.csp_auth_klen = ks->ks_class->ec_keybits / 8; 97 csp.csp_auth_mlen = 12; 98 csp.csp_auth_key = ks->ks_key; 99 crypto_newsession(&as->as_session_sha1, &csp, 100 CRYPTOCAP_F_HARDWARE | CRYPTOCAP_F_SOFTWARE); 101 102 memset(&csp, 0, sizeof(csp)); 103 csp.csp_mode = CSP_MODE_CIPHER; 104 csp.csp_cipher_alg = CRYPTO_AES_CBC; 105 csp.csp_cipher_klen = ks->ks_class->ec_keybits / 8; 106 csp.csp_cipher_key = ks->ks_key; 107 csp.csp_ivlen = 16; 108 crypto_newsession(&as->as_session_aes, &csp, 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_SESS_SYNC(crp->crp_session)) 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, bool encrypt) 142 { 143 struct aes_state *as = ks->ks_priv; 144 struct cryptop *crp; 145 int error; 146 147 crp = crypto_getreq(as->as_session_aes, M_WAITOK); 148 149 crp->crp_payload_start = skip; 150 crp->crp_payload_length = len; 151 crp->crp_op = encrypt ? CRYPTO_OP_ENCRYPT : CRYPTO_OP_DECRYPT; 152 crp->crp_flags = CRYPTO_F_CBIFSYNC | CRYPTO_F_IV_SEPARATE; 153 if (ivec) { 154 memcpy(crp->crp_iv, ivec, 16); 155 } else { 156 memset(crp->crp_iv, 0, 16); 157 } 158 159 if (buftype == CRYPTO_BUF_MBUF) 160 crypto_use_mbuf(crp, buf); 161 else 162 crypto_use_buf(crp, buf, skip + len); 163 crp->crp_opaque = as; 164 crp->crp_callback = aes_crypto_cb; 165 166 error = crypto_dispatch(crp); 167 168 if (!CRYPTO_SESS_SYNC(as->as_session_aes)) { 169 mtx_lock(&as->as_lock); 170 if (!error && !(crp->crp_flags & CRYPTO_F_DONE)) 171 error = msleep(crp, &as->as_lock, 0, "gssaes", 0); 172 mtx_unlock(&as->as_lock); 173 } 174 175 crypto_freereq(crp); 176 } 177 178 static void 179 aes_encrypt(const struct krb5_key_state *ks, struct mbuf *inout, 180 size_t skip, size_t len, void *ivec, size_t ivlen) 181 { 182 size_t blocklen = 16, plen; 183 struct { 184 uint8_t cn_1[16], cn[16]; 185 } last2; 186 int i, off; 187 188 /* 189 * AES encryption with cyphertext stealing: 190 * 191 * CTSencrypt(P[0], ..., P[n], IV, K): 192 * len = length(P[n]) 193 * (C[0], ..., C[n-2], E[n-1]) = 194 * CBCencrypt(P[0], ..., P[n-1], IV, K) 195 * P = pad(P[n], 0, blocksize) 196 * E[n] = CBCencrypt(P, E[n-1], K); 197 * C[n-1] = E[n] 198 * C[n] = E[n-1]{0..len-1} 199 */ 200 plen = len % blocklen; 201 if (len == blocklen) { 202 /* 203 * Note: caller will ensure len >= blocklen. 204 */ 205 aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, skip, len, ivec, 206 true); 207 } else if (plen == 0) { 208 /* 209 * This is equivalent to CBC mode followed by swapping 210 * the last two blocks. We assume that neither of the 211 * last two blocks cross iov boundaries. 212 */ 213 aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, skip, len, ivec, 214 true); 215 off = skip + len - 2 * blocklen; 216 m_copydata(inout, off, 2 * blocklen, (void*) &last2); 217 m_copyback(inout, off, blocklen, last2.cn); 218 m_copyback(inout, off + blocklen, blocklen, last2.cn_1); 219 } else { 220 /* 221 * This is the difficult case. We encrypt all but the 222 * last partial block first. We then create a padded 223 * copy of the last block and encrypt that using the 224 * second to last encrypted block as IV. Once we have 225 * the encrypted versions of the last two blocks, we 226 * reshuffle to create the final result. 227 */ 228 aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, skip, len - plen, 229 ivec, true); 230 231 /* 232 * Copy out the last two blocks, pad the last block 233 * and encrypt it. Rearrange to get the final 234 * result. The cyphertext for cn_1 is in cn. The 235 * cyphertext for cn is the first plen bytes of what 236 * is in cn_1 now. 237 */ 238 off = skip + len - blocklen - plen; 239 m_copydata(inout, off, blocklen + plen, (void*) &last2); 240 for (i = plen; i < blocklen; i++) 241 last2.cn[i] = 0; 242 aes_encrypt_1(ks, CRYPTO_BUF_CONTIG, last2.cn, 0, blocklen, 243 last2.cn_1, true); 244 m_copyback(inout, off, blocklen, last2.cn); 245 m_copyback(inout, off + blocklen, plen, last2.cn_1); 246 } 247 } 248 249 static void 250 aes_decrypt(const struct krb5_key_state *ks, struct mbuf *inout, 251 size_t skip, size_t len, void *ivec, size_t ivlen) 252 { 253 size_t blocklen = 16, plen; 254 struct { 255 uint8_t cn_1[16], cn[16]; 256 } last2; 257 int i, off, t; 258 259 /* 260 * AES decryption with cyphertext stealing: 261 * 262 * CTSencrypt(C[0], ..., C[n], IV, K): 263 * len = length(C[n]) 264 * E[n] = C[n-1] 265 * X = decrypt(E[n], K) 266 * P[n] = (X ^ C[n]){0..len-1} 267 * E[n-1] = {C[n,0],...,C[n,len-1],X[len],...,X[blocksize-1]} 268 * (P[0],...,P[n-1]) = CBCdecrypt(C[0],...,C[n-2],E[n-1], IV, K) 269 */ 270 plen = len % blocklen; 271 if (len == blocklen) { 272 /* 273 * Note: caller will ensure len >= blocklen. 274 */ 275 aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, skip, len, ivec, 276 false); 277 } else if (plen == 0) { 278 /* 279 * This is equivalent to CBC mode followed by swapping 280 * the last two blocks. 281 */ 282 off = skip + len - 2 * blocklen; 283 m_copydata(inout, off, 2 * blocklen, (void*) &last2); 284 m_copyback(inout, off, blocklen, last2.cn); 285 m_copyback(inout, off + blocklen, blocklen, last2.cn_1); 286 aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, skip, len, ivec, 287 false); 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_BUF_MBUF, inout, off, blocklen, 302 NULL, false); 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_BUF_MBUF, inout, skip, len - plen, 313 ivec, false); 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 int error; 325 326 crp = crypto_getreq(as->as_session_sha1, M_WAITOK); 327 328 crp->crp_payload_start = skip; 329 crp->crp_payload_length = inlen; 330 crp->crp_digest_start = skip + inlen; 331 crp->crp_flags = CRYPTO_F_CBIFSYNC; 332 crypto_use_mbuf(crp, inout); 333 crp->crp_opaque = as; 334 crp->crp_callback = aes_crypto_cb; 335 336 error = crypto_dispatch(crp); 337 338 if (!CRYPTO_SESS_SYNC(as->as_session_sha1)) { 339 mtx_lock(&as->as_lock); 340 if (!error && !(crp->crp_flags & CRYPTO_F_DONE)) 341 error = msleep(crp, &as->as_lock, 0, "gssaes", 0); 342 mtx_unlock(&as->as_lock); 343 } 344 345 crypto_freereq(crp); 346 } 347 348 struct krb5_encryption_class krb5_aes128_encryption_class = { 349 "aes128-cts-hmac-sha1-96", /* name */ 350 ETYPE_AES128_CTS_HMAC_SHA1_96, /* etype */ 351 EC_DERIVED_KEYS, /* flags */ 352 16, /* blocklen */ 353 1, /* msgblocklen */ 354 12, /* checksumlen */ 355 128, /* keybits */ 356 16, /* keylen */ 357 aes_init, 358 aes_destroy, 359 aes_set_key, 360 aes_random_to_key, 361 aes_encrypt, 362 aes_decrypt, 363 aes_checksum 364 }; 365 366 struct krb5_encryption_class krb5_aes256_encryption_class = { 367 "aes256-cts-hmac-sha1-96", /* name */ 368 ETYPE_AES256_CTS_HMAC_SHA1_96, /* etype */ 369 EC_DERIVED_KEYS, /* flags */ 370 16, /* blocklen */ 371 1, /* msgblocklen */ 372 12, /* checksumlen */ 373 256, /* keybits */ 374 32, /* keylen */ 375 aes_init, 376 aes_destroy, 377 aes_set_key, 378 aes_random_to_key, 379 aes_encrypt, 380 aes_decrypt, 381 aes_checksum 382 }; 383