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_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, 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 crp->crp_buf_type = buftype; 160 crp->crp_buf = buf; 161 crp->crp_opaque = as; 162 crp->crp_callback = aes_crypto_cb; 163 164 error = crypto_dispatch(crp); 165 166 if ((crypto_ses2caps(as->as_session_aes) & CRYPTOCAP_F_SYNC) == 0) { 167 mtx_lock(&as->as_lock); 168 if (!error && !(crp->crp_flags & CRYPTO_F_DONE)) 169 error = msleep(crp, &as->as_lock, 0, "gssaes", 0); 170 mtx_unlock(&as->as_lock); 171 } 172 173 crypto_freereq(crp); 174 } 175 176 static void 177 aes_encrypt(const struct krb5_key_state *ks, struct mbuf *inout, 178 size_t skip, size_t len, void *ivec, size_t ivlen) 179 { 180 size_t blocklen = 16, plen; 181 struct { 182 uint8_t cn_1[16], cn[16]; 183 } last2; 184 int i, off; 185 186 /* 187 * AES encryption with cyphertext stealing: 188 * 189 * CTSencrypt(P[0], ..., P[n], IV, K): 190 * len = length(P[n]) 191 * (C[0], ..., C[n-2], E[n-1]) = 192 * CBCencrypt(P[0], ..., P[n-1], IV, K) 193 * P = pad(P[n], 0, blocksize) 194 * E[n] = CBCencrypt(P, E[n-1], K); 195 * C[n-1] = E[n] 196 * C[n] = E[n-1]{0..len-1} 197 */ 198 plen = len % blocklen; 199 if (len == blocklen) { 200 /* 201 * Note: caller will ensure len >= blocklen. 202 */ 203 aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, skip, len, ivec, 204 true); 205 } else if (plen == 0) { 206 /* 207 * This is equivalent to CBC mode followed by swapping 208 * the last two blocks. We assume that neither of the 209 * last two blocks cross iov boundaries. 210 */ 211 aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, skip, len, ivec, 212 true); 213 off = skip + len - 2 * blocklen; 214 m_copydata(inout, off, 2 * blocklen, (void*) &last2); 215 m_copyback(inout, off, blocklen, last2.cn); 216 m_copyback(inout, off + blocklen, blocklen, last2.cn_1); 217 } else { 218 /* 219 * This is the difficult case. We encrypt all but the 220 * last partial block first. We then create a padded 221 * copy of the last block and encrypt that using the 222 * second to last encrypted block as IV. Once we have 223 * the encrypted versions of the last two blocks, we 224 * reshuffle to create the final result. 225 */ 226 aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, skip, len - plen, 227 ivec, true); 228 229 /* 230 * Copy out the last two blocks, pad the last block 231 * and encrypt it. Rearrange to get the final 232 * result. The cyphertext for cn_1 is in cn. The 233 * cyphertext for cn is the first plen bytes of what 234 * is in cn_1 now. 235 */ 236 off = skip + len - blocklen - plen; 237 m_copydata(inout, off, blocklen + plen, (void*) &last2); 238 for (i = plen; i < blocklen; i++) 239 last2.cn[i] = 0; 240 aes_encrypt_1(ks, CRYPTO_BUF_CONTIG, last2.cn, 0, blocklen, 241 last2.cn_1, true); 242 m_copyback(inout, off, blocklen, last2.cn); 243 m_copyback(inout, off + blocklen, plen, last2.cn_1); 244 } 245 } 246 247 static void 248 aes_decrypt(const struct krb5_key_state *ks, struct mbuf *inout, 249 size_t skip, size_t len, void *ivec, size_t ivlen) 250 { 251 size_t blocklen = 16, plen; 252 struct { 253 uint8_t cn_1[16], cn[16]; 254 } last2; 255 int i, off, t; 256 257 /* 258 * AES decryption with cyphertext stealing: 259 * 260 * CTSencrypt(C[0], ..., C[n], IV, K): 261 * len = length(C[n]) 262 * E[n] = C[n-1] 263 * X = decrypt(E[n], K) 264 * P[n] = (X ^ C[n]){0..len-1} 265 * E[n-1] = {C[n,0],...,C[n,len-1],X[len],...,X[blocksize-1]} 266 * (P[0],...,P[n-1]) = CBCdecrypt(C[0],...,C[n-2],E[n-1], IV, K) 267 */ 268 plen = len % blocklen; 269 if (len == blocklen) { 270 /* 271 * Note: caller will ensure len >= blocklen. 272 */ 273 aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, skip, len, ivec, 274 false); 275 } else if (plen == 0) { 276 /* 277 * This is equivalent to CBC mode followed by swapping 278 * the last two blocks. 279 */ 280 off = skip + len - 2 * blocklen; 281 m_copydata(inout, off, 2 * blocklen, (void*) &last2); 282 m_copyback(inout, off, blocklen, last2.cn); 283 m_copyback(inout, off + blocklen, blocklen, last2.cn_1); 284 aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, skip, len, ivec, 285 false); 286 } else { 287 /* 288 * This is the difficult case. We first decrypt the 289 * second to last block with a zero IV to make X. The 290 * plaintext for the last block is the XOR of X and 291 * the last cyphertext block. 292 * 293 * We derive a new cypher text for the second to last 294 * block by mixing the unused bytes of X with the last 295 * cyphertext block. The result of that can be 296 * decrypted with the rest in CBC mode. 297 */ 298 off = skip + len - plen - blocklen; 299 aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, off, blocklen, 300 NULL, false); 301 m_copydata(inout, off, blocklen + plen, (void*) &last2); 302 303 for (i = 0; i < plen; i++) { 304 t = last2.cn[i]; 305 last2.cn[i] ^= last2.cn_1[i]; 306 last2.cn_1[i] = t; 307 } 308 309 m_copyback(inout, off, blocklen + plen, (void*) &last2); 310 aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, skip, len - plen, 311 ivec, false); 312 } 313 314 } 315 316 static void 317 aes_checksum(const struct krb5_key_state *ks, int usage, 318 struct mbuf *inout, size_t skip, size_t inlen, size_t outlen) 319 { 320 struct aes_state *as = ks->ks_priv; 321 struct cryptop *crp; 322 int error; 323 324 crp = crypto_getreq(as->as_session_sha1, M_WAITOK); 325 326 crp->crp_payload_start = skip; 327 crp->crp_payload_length = inlen; 328 crp->crp_digest_start = skip + inlen; 329 crp->crp_flags = CRYPTO_F_CBIFSYNC; 330 crp->crp_buf_type = CRYPTO_BUF_MBUF; 331 crp->crp_mbuf = inout; 332 crp->crp_opaque = as; 333 crp->crp_callback = aes_crypto_cb; 334 335 error = crypto_dispatch(crp); 336 337 if ((crypto_ses2caps(as->as_session_sha1) & CRYPTOCAP_F_SYNC) == 0) { 338 mtx_lock(&as->as_lock); 339 if (!error && !(crp->crp_flags & CRYPTO_F_DONE)) 340 error = msleep(crp, &as->as_lock, 0, "gssaes", 0); 341 mtx_unlock(&as->as_lock); 342 } 343 344 crypto_freereq(crp); 345 } 346 347 struct krb5_encryption_class krb5_aes128_encryption_class = { 348 "aes128-cts-hmac-sha1-96", /* name */ 349 ETYPE_AES128_CTS_HMAC_SHA1_96, /* etype */ 350 EC_DERIVED_KEYS, /* flags */ 351 16, /* blocklen */ 352 1, /* msgblocklen */ 353 12, /* checksumlen */ 354 128, /* keybits */ 355 16, /* keylen */ 356 aes_init, 357 aes_destroy, 358 aes_set_key, 359 aes_random_to_key, 360 aes_encrypt, 361 aes_decrypt, 362 aes_checksum 363 }; 364 365 struct krb5_encryption_class krb5_aes256_encryption_class = { 366 "aes256-cts-hmac-sha1-96", /* name */ 367 ETYPE_AES256_CTS_HMAC_SHA1_96, /* etype */ 368 EC_DERIVED_KEYS, /* flags */ 369 16, /* blocklen */ 370 1, /* msgblocklen */ 371 12, /* checksumlen */ 372 256, /* keybits */ 373 32, /* keylen */ 374 aes_init, 375 aes_destroy, 376 aes_set_key, 377 aes_random_to_key, 378 aes_encrypt, 379 aes_decrypt, 380 aes_checksum 381 }; 382