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 int error; 120 struct aes_state *as = (struct aes_state *) crp->crp_opaque; 121 122 if (CRYPTO_SESS_SYNC(crp->crp_session)) 123 return (0); 124 125 error = crp->crp_etype; 126 if (error == EAGAIN) 127 error = crypto_dispatch(crp); 128 mtx_lock(&as->as_lock); 129 if (error || (crp->crp_flags & CRYPTO_F_DONE)) 130 wakeup(crp); 131 mtx_unlock(&as->as_lock); 132 133 return (0); 134 } 135 136 static void 137 aes_encrypt_1(const struct krb5_key_state *ks, int buftype, void *buf, 138 size_t skip, size_t len, void *ivec, bool encrypt) 139 { 140 struct aes_state *as = ks->ks_priv; 141 struct cryptop *crp; 142 int error; 143 144 crp = crypto_getreq(as->as_session_aes, M_WAITOK); 145 146 crp->crp_payload_start = skip; 147 crp->crp_payload_length = len; 148 crp->crp_op = encrypt ? CRYPTO_OP_ENCRYPT : CRYPTO_OP_DECRYPT; 149 crp->crp_flags = CRYPTO_F_CBIFSYNC | CRYPTO_F_IV_SEPARATE; 150 if (ivec) { 151 memcpy(crp->crp_iv, ivec, 16); 152 } else { 153 memset(crp->crp_iv, 0, 16); 154 } 155 156 if (buftype == CRYPTO_BUF_MBUF) 157 crypto_use_mbuf(crp, buf); 158 else 159 crypto_use_buf(crp, buf, skip + len); 160 crp->crp_opaque = as; 161 crp->crp_callback = aes_crypto_cb; 162 163 error = crypto_dispatch(crp); 164 165 if (!CRYPTO_SESS_SYNC(as->as_session_aes)) { 166 mtx_lock(&as->as_lock); 167 if (!error && !(crp->crp_flags & CRYPTO_F_DONE)) 168 error = msleep(crp, &as->as_lock, 0, "gssaes", 0); 169 mtx_unlock(&as->as_lock); 170 } 171 172 crypto_freereq(crp); 173 } 174 175 static void 176 aes_encrypt(const struct krb5_key_state *ks, struct mbuf *inout, 177 size_t skip, size_t len, void *ivec, size_t ivlen) 178 { 179 size_t blocklen = 16, plen; 180 struct { 181 uint8_t cn_1[16], cn[16]; 182 } last2; 183 int i, off; 184 185 /* 186 * AES encryption with cyphertext stealing: 187 * 188 * CTSencrypt(P[0], ..., P[n], IV, K): 189 * len = length(P[n]) 190 * (C[0], ..., C[n-2], E[n-1]) = 191 * CBCencrypt(P[0], ..., P[n-1], IV, K) 192 * P = pad(P[n], 0, blocksize) 193 * E[n] = CBCencrypt(P, E[n-1], K); 194 * C[n-1] = E[n] 195 * C[n] = E[n-1]{0..len-1} 196 */ 197 plen = len % blocklen; 198 if (len == blocklen) { 199 /* 200 * Note: caller will ensure len >= blocklen. 201 */ 202 aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, skip, len, ivec, 203 true); 204 } else if (plen == 0) { 205 /* 206 * This is equivalent to CBC mode followed by swapping 207 * the last two blocks. We assume that neither of the 208 * last two blocks cross iov boundaries. 209 */ 210 aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, skip, len, ivec, 211 true); 212 off = skip + len - 2 * blocklen; 213 m_copydata(inout, off, 2 * blocklen, (void*) &last2); 214 m_copyback(inout, off, blocklen, last2.cn); 215 m_copyback(inout, off + blocklen, blocklen, last2.cn_1); 216 } else { 217 /* 218 * This is the difficult case. We encrypt all but the 219 * last partial block first. We then create a padded 220 * copy of the last block and encrypt that using the 221 * second to last encrypted block as IV. Once we have 222 * the encrypted versions of the last two blocks, we 223 * reshuffle to create the final result. 224 */ 225 aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, skip, len - plen, 226 ivec, true); 227 228 /* 229 * Copy out the last two blocks, pad the last block 230 * and encrypt it. Rearrange to get the final 231 * result. The cyphertext for cn_1 is in cn. The 232 * cyphertext for cn is the first plen bytes of what 233 * is in cn_1 now. 234 */ 235 off = skip + len - blocklen - plen; 236 m_copydata(inout, off, blocklen + plen, (void*) &last2); 237 for (i = plen; i < blocklen; i++) 238 last2.cn[i] = 0; 239 aes_encrypt_1(ks, CRYPTO_BUF_CONTIG, last2.cn, 0, blocklen, 240 last2.cn_1, true); 241 m_copyback(inout, off, blocklen, last2.cn); 242 m_copyback(inout, off + blocklen, plen, last2.cn_1); 243 } 244 } 245 246 static void 247 aes_decrypt(const struct krb5_key_state *ks, struct mbuf *inout, 248 size_t skip, size_t len, void *ivec, size_t ivlen) 249 { 250 size_t blocklen = 16, plen; 251 struct { 252 uint8_t cn_1[16], cn[16]; 253 } last2; 254 int i, off, t; 255 256 /* 257 * AES decryption with cyphertext stealing: 258 * 259 * CTSencrypt(C[0], ..., C[n], IV, K): 260 * len = length(C[n]) 261 * E[n] = C[n-1] 262 * X = decrypt(E[n], K) 263 * P[n] = (X ^ C[n]){0..len-1} 264 * E[n-1] = {C[n,0],...,C[n,len-1],X[len],...,X[blocksize-1]} 265 * (P[0],...,P[n-1]) = CBCdecrypt(C[0],...,C[n-2],E[n-1], IV, K) 266 */ 267 plen = len % blocklen; 268 if (len == blocklen) { 269 /* 270 * Note: caller will ensure len >= blocklen. 271 */ 272 aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, skip, len, ivec, 273 false); 274 } else if (plen == 0) { 275 /* 276 * This is equivalent to CBC mode followed by swapping 277 * the last two blocks. 278 */ 279 off = skip + len - 2 * blocklen; 280 m_copydata(inout, off, 2 * blocklen, (void*) &last2); 281 m_copyback(inout, off, blocklen, last2.cn); 282 m_copyback(inout, off + blocklen, blocklen, last2.cn_1); 283 aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, skip, len, ivec, 284 false); 285 } else { 286 /* 287 * This is the difficult case. We first decrypt the 288 * second to last block with a zero IV to make X. The 289 * plaintext for the last block is the XOR of X and 290 * the last cyphertext block. 291 * 292 * We derive a new cypher text for the second to last 293 * block by mixing the unused bytes of X with the last 294 * cyphertext block. The result of that can be 295 * decrypted with the rest in CBC mode. 296 */ 297 off = skip + len - plen - blocklen; 298 aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, off, blocklen, 299 NULL, false); 300 m_copydata(inout, off, blocklen + plen, (void*) &last2); 301 302 for (i = 0; i < plen; i++) { 303 t = last2.cn[i]; 304 last2.cn[i] ^= last2.cn_1[i]; 305 last2.cn_1[i] = t; 306 } 307 308 m_copyback(inout, off, blocklen + plen, (void*) &last2); 309 aes_encrypt_1(ks, CRYPTO_BUF_MBUF, inout, skip, len - plen, 310 ivec, false); 311 } 312 313 } 314 315 static void 316 aes_checksum(const struct krb5_key_state *ks, int usage, 317 struct mbuf *inout, size_t skip, size_t inlen, size_t outlen) 318 { 319 struct aes_state *as = ks->ks_priv; 320 struct cryptop *crp; 321 int error; 322 323 crp = crypto_getreq(as->as_session_sha1, M_WAITOK); 324 325 crp->crp_payload_start = skip; 326 crp->crp_payload_length = inlen; 327 crp->crp_digest_start = skip + inlen; 328 crp->crp_flags = CRYPTO_F_CBIFSYNC; 329 crypto_use_mbuf(crp, inout); 330 crp->crp_opaque = as; 331 crp->crp_callback = aes_crypto_cb; 332 333 error = crypto_dispatch(crp); 334 335 if (!CRYPTO_SESS_SYNC(as->as_session_sha1)) { 336 mtx_lock(&as->as_lock); 337 if (!error && !(crp->crp_flags & CRYPTO_F_DONE)) 338 error = msleep(crp, &as->as_lock, 0, "gssaes", 0); 339 mtx_unlock(&as->as_lock); 340 } 341 342 crypto_freereq(crp); 343 } 344 345 struct krb5_encryption_class krb5_aes128_encryption_class = { 346 "aes128-cts-hmac-sha1-96", /* name */ 347 ETYPE_AES128_CTS_HMAC_SHA1_96, /* etype */ 348 EC_DERIVED_KEYS, /* flags */ 349 16, /* blocklen */ 350 1, /* msgblocklen */ 351 12, /* checksumlen */ 352 128, /* keybits */ 353 16, /* keylen */ 354 aes_init, 355 aes_destroy, 356 aes_set_key, 357 aes_random_to_key, 358 aes_encrypt, 359 aes_decrypt, 360 aes_checksum 361 }; 362 363 struct krb5_encryption_class krb5_aes256_encryption_class = { 364 "aes256-cts-hmac-sha1-96", /* name */ 365 ETYPE_AES256_CTS_HMAC_SHA1_96, /* etype */ 366 EC_DERIVED_KEYS, /* flags */ 367 16, /* blocklen */ 368 1, /* msgblocklen */ 369 12, /* checksumlen */ 370 256, /* keybits */ 371 32, /* keylen */ 372 aes_init, 373 aes_destroy, 374 aes_set_key, 375 aes_random_to_key, 376 aes_encrypt, 377 aes_decrypt, 378 aes_checksum 379 }; 380