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
aes_init(struct krb5_key_state * ks)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
aes_destroy(struct krb5_key_state * ks)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
aes_set_key(struct krb5_key_state * ks,const void * in)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
aes_random_to_key(struct krb5_key_state * ks,const void * in)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
aes_crypto_cb(struct cryptop * crp)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
aes_encrypt_1(const struct krb5_key_state * ks,int buftype,void * buf,size_t skip,size_t len,void * ivec,bool encrypt)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
aes_encrypt(const struct krb5_key_state * ks,struct mbuf * inout,size_t skip,size_t len,void * ivec,size_t ivlen)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
aes_decrypt(const struct krb5_key_state * ks,struct mbuf * inout,size_t skip,size_t len,void * ivec,size_t ivlen)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
aes_checksum(const struct krb5_key_state * ks,int usage,struct mbuf * inout,size_t skip,size_t inlen,size_t outlen)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