1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 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/param.h> 31 #include <sys/lock.h> 32 #include <sys/malloc.h> 33 #include <sys/mutex.h> 34 #include <sys/kobj.h> 35 #include <sys/mbuf.h> 36 #include <opencrypto/cryptodev.h> 37 38 #include <kgssapi/gssapi.h> 39 #include <kgssapi/gssapi_impl.h> 40 41 #include "kcrypto.h" 42 43 struct aes_state { 44 struct mtx as_lock; 45 crypto_session_t as_session_aes; 46 crypto_session_t as_session_sha1; 47 }; 48 49 static void 50 aes_init(struct krb5_key_state *ks) 51 { 52 struct aes_state *as; 53 54 as = malloc(sizeof(struct aes_state), M_GSSAPI, M_WAITOK|M_ZERO); 55 mtx_init(&as->as_lock, "gss aes lock", NULL, MTX_DEF); 56 ks->ks_priv = as; 57 } 58 59 static void 60 aes_destroy(struct krb5_key_state *ks) 61 { 62 struct aes_state *as = ks->ks_priv; 63 64 if (as->as_session_aes != 0) 65 crypto_freesession(as->as_session_aes); 66 if (as->as_session_sha1 != 0) 67 crypto_freesession(as->as_session_sha1); 68 mtx_destroy(&as->as_lock); 69 free(ks->ks_priv, M_GSSAPI); 70 } 71 72 static void 73 aes_set_key(struct krb5_key_state *ks, const void *in) 74 { 75 void *kp = ks->ks_key; 76 struct aes_state *as = ks->ks_priv; 77 struct crypto_session_params csp; 78 79 if (kp != in) 80 bcopy(in, kp, ks->ks_class->ec_keylen); 81 82 if (as->as_session_aes != 0) 83 crypto_freesession(as->as_session_aes); 84 if (as->as_session_sha1 != 0) 85 crypto_freesession(as->as_session_sha1); 86 87 /* 88 * We only want the first 96 bits of the HMAC. 89 */ 90 memset(&csp, 0, sizeof(csp)); 91 csp.csp_mode = CSP_MODE_DIGEST; 92 csp.csp_auth_alg = CRYPTO_SHA1_HMAC; 93 csp.csp_auth_klen = ks->ks_class->ec_keybits / 8; 94 csp.csp_auth_mlen = 12; 95 csp.csp_auth_key = ks->ks_key; 96 crypto_newsession(&as->as_session_sha1, &csp, 97 CRYPTOCAP_F_HARDWARE | CRYPTOCAP_F_SOFTWARE); 98 99 memset(&csp, 0, sizeof(csp)); 100 csp.csp_mode = CSP_MODE_CIPHER; 101 csp.csp_cipher_alg = CRYPTO_AES_CBC; 102 csp.csp_cipher_klen = ks->ks_class->ec_keybits / 8; 103 csp.csp_cipher_key = ks->ks_key; 104 csp.csp_ivlen = 16; 105 crypto_newsession(&as->as_session_aes, &csp, 106 CRYPTOCAP_F_HARDWARE | CRYPTOCAP_F_SOFTWARE); 107 } 108 109 static void 110 aes_random_to_key(struct krb5_key_state *ks, const void *in) 111 { 112 113 aes_set_key(ks, in); 114 } 115 116 static int 117 aes_crypto_cb(struct cryptop *crp) 118 { 119 struct aes_state *as = (struct aes_state *) crp->crp_opaque; 120 121 if (CRYPTO_SESS_SYNC(crp->crp_session)) { 122 KASSERT(crp->crp_etype == 0, 123 ("%s: callback with error %d", __func__, crp->crp_etype)); 124 return (0); 125 } 126 127 if (crp->crp_etype == EAGAIN) { 128 crp->crp_etype = 0; 129 (void)crypto_dispatch(crp); 130 } else { 131 mtx_lock(&as->as_lock); 132 crp->crp_opaque = NULL; 133 wakeup(crp); 134 mtx_unlock(&as->as_lock); 135 } 136 137 return (0); 138 } 139 140 static void 141 aes_encrypt_1(const struct krb5_key_state *ks, int buftype, void *buf, 142 size_t skip, size_t len, void *ivec, bool encrypt) 143 { 144 struct aes_state *as = ks->ks_priv; 145 struct cryptop *crp; 146 int error; 147 148 crp = crypto_getreq(as->as_session_aes, M_WAITOK); 149 150 crp->crp_payload_start = skip; 151 crp->crp_payload_length = len; 152 crp->crp_op = encrypt ? CRYPTO_OP_ENCRYPT : CRYPTO_OP_DECRYPT; 153 crp->crp_flags = CRYPTO_F_CBIFSYNC | CRYPTO_F_IV_SEPARATE; 154 if (ivec) { 155 memcpy(crp->crp_iv, ivec, 16); 156 } else { 157 memset(crp->crp_iv, 0, 16); 158 } 159 160 if (buftype == CRYPTO_BUF_MBUF) 161 crypto_use_mbuf(crp, buf); 162 else 163 crypto_use_buf(crp, buf, skip + len); 164 crp->crp_opaque = as; 165 crp->crp_callback = aes_crypto_cb; 166 167 error = crypto_dispatch(crp); 168 169 if (!CRYPTO_SESS_SYNC(as->as_session_aes)) { 170 mtx_lock(&as->as_lock); 171 if (error == 0 && crp->crp_opaque != NULL) 172 error = msleep(crp, &as->as_lock, 0, "gssaes", 0); 173 mtx_unlock(&as->as_lock); 174 } 175 if (crp->crp_etype != 0) 176 panic("%s: crypto req failed: %d", __func__, crp->crp_etype); 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_BUF_MBUF, inout, skip, len, ivec, 208 true); 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_BUF_MBUF, inout, skip, len, ivec, 216 true); 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_BUF_MBUF, inout, skip, len - plen, 231 ivec, true); 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, CRYPTO_BUF_CONTIG, last2.cn, 0, blocklen, 245 last2.cn_1, true); 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_BUF_MBUF, inout, skip, len, ivec, 278 false); 279 } else if (plen == 0) { 280 /* 281 * This is equivalent to CBC mode followed by swapping 282 * the last two blocks. 283 */ 284 off = skip + len - 2 * blocklen; 285 m_copydata(inout, off, 2 * blocklen, (void*) &last2); 286 m_copyback(inout, off, blocklen, last2.cn); 287 m_copyback(inout, off + blocklen, blocklen, last2.cn_1); 288 aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, skip, len, ivec, 289 false); 290 } else { 291 /* 292 * This is the difficult case. We first decrypt the 293 * second to last block with a zero IV to make X. The 294 * plaintext for the last block is the XOR of X and 295 * the last cyphertext block. 296 * 297 * We derive a new cypher text for the second to last 298 * block by mixing the unused bytes of X with the last 299 * cyphertext block. The result of that can be 300 * decrypted with the rest in CBC mode. 301 */ 302 off = skip + len - plen - blocklen; 303 aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, off, blocklen, 304 NULL, false); 305 m_copydata(inout, off, blocklen + plen, (void*) &last2); 306 307 for (i = 0; i < plen; i++) { 308 t = last2.cn[i]; 309 last2.cn[i] ^= last2.cn_1[i]; 310 last2.cn_1[i] = t; 311 } 312 313 m_copyback(inout, off, blocklen + plen, (void*) &last2); 314 aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, skip, len - plen, 315 ivec, false); 316 } 317 318 } 319 320 static void 321 aes_checksum(const struct krb5_key_state *ks, int usage, 322 struct mbuf *inout, size_t skip, size_t inlen, size_t outlen) 323 { 324 struct aes_state *as = ks->ks_priv; 325 struct cryptop *crp; 326 int error; 327 328 crp = crypto_getreq(as->as_session_sha1, M_WAITOK); 329 330 crp->crp_payload_start = skip; 331 crp->crp_payload_length = inlen; 332 crp->crp_digest_start = skip + inlen; 333 crp->crp_flags = CRYPTO_F_CBIFSYNC; 334 crypto_use_mbuf(crp, inout); 335 crp->crp_opaque = as; 336 crp->crp_callback = aes_crypto_cb; 337 338 error = crypto_dispatch(crp); 339 340 if (!CRYPTO_SESS_SYNC(as->as_session_sha1)) { 341 mtx_lock(&as->as_lock); 342 if (error == 0 && crp->crp_opaque != NULL) 343 error = msleep(crp, &as->as_lock, 0, "gssaes", 0); 344 mtx_unlock(&as->as_lock); 345 } 346 347 if (crp->crp_etype != 0) 348 panic("%s: crypto req failed: %d", __func__, crp->crp_etype); 349 crypto_freereq(crp); 350 } 351 352 struct krb5_encryption_class krb5_aes128_encryption_class = { 353 "aes128-cts-hmac-sha1-96", /* name */ 354 ETYPE_AES128_CTS_HMAC_SHA1_96, /* etype */ 355 EC_DERIVED_KEYS, /* flags */ 356 16, /* blocklen */ 357 1, /* msgblocklen */ 358 12, /* checksumlen */ 359 128, /* keybits */ 360 16, /* keylen */ 361 aes_init, 362 aes_destroy, 363 aes_set_key, 364 aes_random_to_key, 365 aes_encrypt, 366 aes_decrypt, 367 aes_checksum 368 }; 369 370 struct krb5_encryption_class krb5_aes256_encryption_class = { 371 "aes256-cts-hmac-sha1-96", /* name */ 372 ETYPE_AES256_CTS_HMAC_SHA1_96, /* etype */ 373 EC_DERIVED_KEYS, /* flags */ 374 16, /* blocklen */ 375 1, /* msgblocklen */ 376 12, /* checksumlen */ 377 256, /* keybits */ 378 32, /* keylen */ 379 aes_init, 380 aes_destroy, 381 aes_set_key, 382 aes_random_to_key, 383 aes_encrypt, 384 aes_decrypt, 385 aes_checksum 386 }; 387