1 /*-
2 * Copyright (c) 2008 Isilon Inc http://www.isilon.com/
3 * Authors: Doug Rabson <dfr@rabson.org>
4 * Developed with Red Inc: Alfred Perlstein <alfred@freebsd.org>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28 #include <sys/cdefs.h>
29 __FBSDID("$FreeBSD$");
30
31 #include <sys/param.h>
32 #include <sys/lock.h>
33 #include <sys/malloc.h>
34 #include <sys/mutex.h>
35 #include <sys/kobj.h>
36 #include <sys/mbuf.h>
37 #include <opencrypto/cryptodev.h>
38
39 #include <kgssapi/gssapi.h>
40 #include <kgssapi/gssapi_impl.h>
41
42 #include "kcrypto.h"
43
44 struct aes_state {
45 struct mtx as_lock;
46 uint64_t as_session;
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)
65 crypto_freesession(as->as_session);
66 mtx_destroy(&as->as_lock);
67 free(ks->ks_priv, M_GSSAPI);
68 }
69
70 static void
aes_set_key(struct krb5_key_state * ks,const void * in)71 aes_set_key(struct krb5_key_state *ks, const void *in)
72 {
73 void *kp = ks->ks_key;
74 struct aes_state *as = ks->ks_priv;
75 struct cryptoini cri[2];
76
77 if (kp != in)
78 bcopy(in, kp, ks->ks_class->ec_keylen);
79
80 if (as->as_session)
81 crypto_freesession(as->as_session);
82
83 bzero(cri, sizeof(cri));
84
85 /*
86 * We only want the first 96 bits of the HMAC.
87 */
88 cri[0].cri_alg = CRYPTO_SHA1_HMAC;
89 cri[0].cri_klen = ks->ks_class->ec_keybits;
90 cri[0].cri_mlen = 12;
91 cri[0].cri_key = ks->ks_key;
92 cri[0].cri_next = &cri[1];
93
94 cri[1].cri_alg = CRYPTO_AES_CBC;
95 cri[1].cri_klen = ks->ks_class->ec_keybits;
96 cri[1].cri_mlen = 0;
97 cri[1].cri_key = ks->ks_key;
98 cri[1].cri_next = NULL;
99
100 crypto_newsession(&as->as_session, cri,
101 CRYPTOCAP_F_HARDWARE | CRYPTOCAP_F_SOFTWARE);
102 }
103
104 static void
aes_random_to_key(struct krb5_key_state * ks,const void * in)105 aes_random_to_key(struct krb5_key_state *ks, const void *in)
106 {
107
108 aes_set_key(ks, in);
109 }
110
111 static int
aes_crypto_cb(struct cryptop * crp)112 aes_crypto_cb(struct cryptop *crp)
113 {
114 int error;
115 struct aes_state *as = (struct aes_state *) crp->crp_opaque;
116
117 if (CRYPTO_SESID2CAPS(as->as_session) & CRYPTOCAP_F_SYNC)
118 return (0);
119
120 error = crp->crp_etype;
121 if (error == EAGAIN)
122 error = crypto_dispatch(crp);
123 mtx_lock(&as->as_lock);
124 if (error || (crp->crp_flags & CRYPTO_F_DONE))
125 wakeup(crp);
126 mtx_unlock(&as->as_lock);
127
128 return (0);
129 }
130
131 static void
aes_encrypt_1(const struct krb5_key_state * ks,int buftype,void * buf,size_t skip,size_t len,void * ivec,int encdec)132 aes_encrypt_1(const struct krb5_key_state *ks, int buftype, void *buf,
133 size_t skip, size_t len, void *ivec, int encdec)
134 {
135 struct aes_state *as = ks->ks_priv;
136 struct cryptop *crp;
137 struct cryptodesc *crd;
138 int error;
139
140 crp = crypto_getreq(1);
141 crd = crp->crp_desc;
142
143 crd->crd_skip = skip;
144 crd->crd_len = len;
145 crd->crd_flags = CRD_F_IV_EXPLICIT | CRD_F_IV_PRESENT | encdec;
146 if (ivec) {
147 bcopy(ivec, crd->crd_iv, 16);
148 } else {
149 bzero(crd->crd_iv, 16);
150 }
151 crd->crd_next = NULL;
152 crd->crd_alg = CRYPTO_AES_CBC;
153
154 crp->crp_sid = as->as_session;
155 crp->crp_flags = buftype | CRYPTO_F_CBIFSYNC;
156 crp->crp_buf = buf;
157 crp->crp_opaque = (void *) as;
158 crp->crp_callback = aes_crypto_cb;
159
160 error = crypto_dispatch(crp);
161
162 if ((CRYPTO_SESID2CAPS(as->as_session) & CRYPTOCAP_F_SYNC) == 0) {
163 mtx_lock(&as->as_lock);
164 if (!error && !(crp->crp_flags & CRYPTO_F_DONE))
165 error = msleep(crp, &as->as_lock, 0, "gssaes", 0);
166 mtx_unlock(&as->as_lock);
167 }
168
169 crypto_freereq(crp);
170 }
171
172 static void
aes_encrypt(const struct krb5_key_state * ks,struct mbuf * inout,size_t skip,size_t len,void * ivec,size_t ivlen)173 aes_encrypt(const struct krb5_key_state *ks, struct mbuf *inout,
174 size_t skip, size_t len, void *ivec, size_t ivlen)
175 {
176 size_t blocklen = 16, plen;
177 struct {
178 uint8_t cn_1[16], cn[16];
179 } last2;
180 int i, off;
181
182 /*
183 * AES encryption with cyphertext stealing:
184 *
185 * CTSencrypt(P[0], ..., P[n], IV, K):
186 * len = length(P[n])
187 * (C[0], ..., C[n-2], E[n-1]) =
188 * CBCencrypt(P[0], ..., P[n-1], IV, K)
189 * P = pad(P[n], 0, blocksize)
190 * E[n] = CBCencrypt(P, E[n-1], K);
191 * C[n-1] = E[n]
192 * C[n] = E[n-1]{0..len-1}
193 */
194 plen = len % blocklen;
195 if (len == blocklen) {
196 /*
197 * Note: caller will ensure len >= blocklen.
198 */
199 aes_encrypt_1(ks, CRYPTO_F_IMBUF, inout, skip, len, ivec,
200 CRD_F_ENCRYPT);
201 } else if (plen == 0) {
202 /*
203 * This is equivalent to CBC mode followed by swapping
204 * the last two blocks. We assume that neither of the
205 * last two blocks cross iov boundaries.
206 */
207 aes_encrypt_1(ks, CRYPTO_F_IMBUF, inout, skip, len, ivec,
208 CRD_F_ENCRYPT);
209 off = skip + len - 2 * blocklen;
210 m_copydata(inout, off, 2 * blocklen, (void*) &last2);
211 m_copyback(inout, off, blocklen, last2.cn);
212 m_copyback(inout, off + blocklen, blocklen, last2.cn_1);
213 } else {
214 /*
215 * This is the difficult case. We encrypt all but the
216 * last partial block first. We then create a padded
217 * copy of the last block and encrypt that using the
218 * second to last encrypted block as IV. Once we have
219 * the encrypted versions of the last two blocks, we
220 * reshuffle to create the final result.
221 */
222 aes_encrypt_1(ks, CRYPTO_F_IMBUF, inout, skip, len - plen,
223 ivec, CRD_F_ENCRYPT);
224
225 /*
226 * Copy out the last two blocks, pad the last block
227 * and encrypt it. Rearrange to get the final
228 * result. The cyphertext for cn_1 is in cn. The
229 * cyphertext for cn is the first plen bytes of what
230 * is in cn_1 now.
231 */
232 off = skip + len - blocklen - plen;
233 m_copydata(inout, off, blocklen + plen, (void*) &last2);
234 for (i = plen; i < blocklen; i++)
235 last2.cn[i] = 0;
236 aes_encrypt_1(ks, 0, last2.cn, 0, blocklen, last2.cn_1,
237 CRD_F_ENCRYPT);
238 m_copyback(inout, off, blocklen, last2.cn);
239 m_copyback(inout, off + blocklen, plen, last2.cn_1);
240 }
241 }
242
243 static void
aes_decrypt(const struct krb5_key_state * ks,struct mbuf * inout,size_t skip,size_t len,void * ivec,size_t ivlen)244 aes_decrypt(const struct krb5_key_state *ks, struct mbuf *inout,
245 size_t skip, size_t len, void *ivec, size_t ivlen)
246 {
247 size_t blocklen = 16, plen;
248 struct {
249 uint8_t cn_1[16], cn[16];
250 } last2;
251 int i, off, t;
252
253 /*
254 * AES decryption with cyphertext stealing:
255 *
256 * CTSencrypt(C[0], ..., C[n], IV, K):
257 * len = length(C[n])
258 * E[n] = C[n-1]
259 * X = decrypt(E[n], K)
260 * P[n] = (X ^ C[n]){0..len-1}
261 * E[n-1] = {C[n,0],...,C[n,len-1],X[len],...,X[blocksize-1]}
262 * (P[0],...,P[n-1]) = CBCdecrypt(C[0],...,C[n-2],E[n-1], IV, K)
263 */
264 plen = len % blocklen;
265 if (len == blocklen) {
266 /*
267 * Note: caller will ensure len >= blocklen.
268 */
269 aes_encrypt_1(ks, CRYPTO_F_IMBUF, inout, skip, len, ivec, 0);
270 } else if (plen == 0) {
271 /*
272 * This is equivalent to CBC mode followed by swapping
273 * the last two blocks.
274 */
275 off = skip + len - 2 * blocklen;
276 m_copydata(inout, off, 2 * blocklen, (void*) &last2);
277 m_copyback(inout, off, blocklen, last2.cn);
278 m_copyback(inout, off + blocklen, blocklen, last2.cn_1);
279 aes_encrypt_1(ks, CRYPTO_F_IMBUF, inout, skip, len, ivec, 0);
280 } else {
281 /*
282 * This is the difficult case. We first decrypt the
283 * second to last block with a zero IV to make X. The
284 * plaintext for the last block is the XOR of X and
285 * the last cyphertext block.
286 *
287 * We derive a new cypher text for the second to last
288 * block by mixing the unused bytes of X with the last
289 * cyphertext block. The result of that can be
290 * decrypted with the rest in CBC mode.
291 */
292 off = skip + len - plen - blocklen;
293 aes_encrypt_1(ks, CRYPTO_F_IMBUF, inout, off, blocklen,
294 NULL, 0);
295 m_copydata(inout, off, blocklen + plen, (void*) &last2);
296
297 for (i = 0; i < plen; i++) {
298 t = last2.cn[i];
299 last2.cn[i] ^= last2.cn_1[i];
300 last2.cn_1[i] = t;
301 }
302
303 m_copyback(inout, off, blocklen + plen, (void*) &last2);
304 aes_encrypt_1(ks, CRYPTO_F_IMBUF, inout, skip, len - plen,
305 ivec, 0);
306 }
307
308 }
309
310 static void
aes_checksum(const struct krb5_key_state * ks,int usage,struct mbuf * inout,size_t skip,size_t inlen,size_t outlen)311 aes_checksum(const struct krb5_key_state *ks, int usage,
312 struct mbuf *inout, size_t skip, size_t inlen, size_t outlen)
313 {
314 struct aes_state *as = ks->ks_priv;
315 struct cryptop *crp;
316 struct cryptodesc *crd;
317 int error;
318
319 crp = crypto_getreq(1);
320 crd = crp->crp_desc;
321
322 crd->crd_skip = skip;
323 crd->crd_len = inlen;
324 crd->crd_inject = skip + inlen;
325 crd->crd_flags = 0;
326 crd->crd_next = NULL;
327 crd->crd_alg = CRYPTO_SHA1_HMAC;
328
329 crp->crp_sid = as->as_session;
330 crp->crp_ilen = inlen;
331 crp->crp_olen = 12;
332 crp->crp_etype = 0;
333 crp->crp_flags = CRYPTO_F_IMBUF | CRYPTO_F_CBIFSYNC;
334 crp->crp_buf = (void *) inout;
335 crp->crp_opaque = (void *) as;
336 crp->crp_callback = aes_crypto_cb;
337
338 error = crypto_dispatch(crp);
339
340 if ((CRYPTO_SESID2CAPS(as->as_session) & CRYPTOCAP_F_SYNC) == 0) {
341 mtx_lock(&as->as_lock);
342 if (!error && !(crp->crp_flags & CRYPTO_F_DONE))
343 error = msleep(crp, &as->as_lock, 0, "gssaes", 0);
344 mtx_unlock(&as->as_lock);
345 }
346
347 crypto_freereq(crp);
348 }
349
350 struct krb5_encryption_class krb5_aes128_encryption_class = {
351 "aes128-cts-hmac-sha1-96", /* name */
352 ETYPE_AES128_CTS_HMAC_SHA1_96, /* etype */
353 EC_DERIVED_KEYS, /* flags */
354 16, /* blocklen */
355 1, /* msgblocklen */
356 12, /* checksumlen */
357 128, /* keybits */
358 16, /* keylen */
359 aes_init,
360 aes_destroy,
361 aes_set_key,
362 aes_random_to_key,
363 aes_encrypt,
364 aes_decrypt,
365 aes_checksum
366 };
367
368 struct krb5_encryption_class krb5_aes256_encryption_class = {
369 "aes256-cts-hmac-sha1-96", /* name */
370 ETYPE_AES256_CTS_HMAC_SHA1_96, /* etype */
371 EC_DERIVED_KEYS, /* flags */
372 16, /* blocklen */
373 1, /* msgblocklen */
374 12, /* checksumlen */
375 256, /* keybits */
376 32, /* keylen */
377 aes_init,
378 aes_destroy,
379 aes_set_key,
380 aes_random_to_key,
381 aes_encrypt,
382 aes_decrypt,
383 aes_checksum
384 };
385