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 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
aes_encrypt_1(const struct krb5_key_state * ks,int buftype,void * buf,size_t skip,size_t len,void * ivec,bool encrypt)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
aes_encrypt(const struct krb5_key_state * ks,struct mbuf * inout,size_t skip,size_t len,void * ivec,size_t ivlen)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
aes_decrypt(const struct krb5_key_state * ks,struct mbuf * inout,size_t skip,size_t len,void * ivec,size_t ivlen)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
aes_checksum(const struct krb5_key_state * ks,int usage,struct mbuf * inout,size_t skip,size_t inlen,size_t outlen)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