1 /*
2 * linux/net/sunrpc/gss_krb5_crypto.c
3 *
4 * Copyright (c) 2000-2008 The Regents of the University of Michigan.
5 * All rights reserved.
6 *
7 * Andy Adamson <andros@umich.edu>
8 * Bruce Fields <bfields@umich.edu>
9 */
10
11 /*
12 * Copyright (C) 1998 by the FundsXpress, INC.
13 *
14 * All rights reserved.
15 *
16 * Export of this software from the United States of America may require
17 * a specific license from the United States Government. It is the
18 * responsibility of any person or organization contemplating export to
19 * obtain such a license before exporting.
20 *
21 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
22 * distribute this software and its documentation for any purpose and
23 * without fee is hereby granted, provided that the above copyright
24 * notice appear in all copies and that both that copyright notice and
25 * this permission notice appear in supporting documentation, and that
26 * the name of FundsXpress. not be used in advertising or publicity pertaining
27 * to distribution of the software without specific, written prior
28 * permission. FundsXpress makes no representations about the suitability of
29 * this software for any purpose. It is provided "as is" without express
30 * or implied warranty.
31 *
32 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
33 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
34 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
35 */
36
37 #include <crypto/algapi.h>
38 #include <crypto/hash.h>
39 #include <crypto/skcipher.h>
40 #include <linux/err.h>
41 #include <linux/types.h>
42 #include <linux/mm.h>
43 #include <linux/scatterlist.h>
44 #include <linux/highmem.h>
45 #include <linux/pagemap.h>
46 #include <linux/random.h>
47 #include <linux/sunrpc/gss_krb5.h>
48 #include <linux/sunrpc/xdr.h>
49
50 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
51 # define RPCDBG_FACILITY RPCDBG_AUTH
52 #endif
53
54 u32
krb5_encrypt(struct crypto_sync_skcipher * tfm,void * iv,void * in,void * out,int length)55 krb5_encrypt(
56 struct crypto_sync_skcipher *tfm,
57 void * iv,
58 void * in,
59 void * out,
60 int length)
61 {
62 u32 ret = -EINVAL;
63 struct scatterlist sg[1];
64 u8 local_iv[GSS_KRB5_MAX_BLOCKSIZE] = {0};
65 SYNC_SKCIPHER_REQUEST_ON_STACK(req, tfm);
66
67 if (length % crypto_sync_skcipher_blocksize(tfm) != 0)
68 goto out;
69
70 if (crypto_sync_skcipher_ivsize(tfm) > GSS_KRB5_MAX_BLOCKSIZE) {
71 dprintk("RPC: gss_k5encrypt: tfm iv size too large %d\n",
72 crypto_sync_skcipher_ivsize(tfm));
73 goto out;
74 }
75
76 if (iv)
77 memcpy(local_iv, iv, crypto_sync_skcipher_ivsize(tfm));
78
79 memcpy(out, in, length);
80 sg_init_one(sg, out, length);
81
82 skcipher_request_set_sync_tfm(req, tfm);
83 skcipher_request_set_callback(req, 0, NULL, NULL);
84 skcipher_request_set_crypt(req, sg, sg, length, local_iv);
85
86 ret = crypto_skcipher_encrypt(req);
87 skcipher_request_zero(req);
88 out:
89 dprintk("RPC: krb5_encrypt returns %d\n", ret);
90 return ret;
91 }
92
93 u32
krb5_decrypt(struct crypto_sync_skcipher * tfm,void * iv,void * in,void * out,int length)94 krb5_decrypt(
95 struct crypto_sync_skcipher *tfm,
96 void * iv,
97 void * in,
98 void * out,
99 int length)
100 {
101 u32 ret = -EINVAL;
102 struct scatterlist sg[1];
103 u8 local_iv[GSS_KRB5_MAX_BLOCKSIZE] = {0};
104 SYNC_SKCIPHER_REQUEST_ON_STACK(req, tfm);
105
106 if (length % crypto_sync_skcipher_blocksize(tfm) != 0)
107 goto out;
108
109 if (crypto_sync_skcipher_ivsize(tfm) > GSS_KRB5_MAX_BLOCKSIZE) {
110 dprintk("RPC: gss_k5decrypt: tfm iv size too large %d\n",
111 crypto_sync_skcipher_ivsize(tfm));
112 goto out;
113 }
114 if (iv)
115 memcpy(local_iv, iv, crypto_sync_skcipher_ivsize(tfm));
116
117 memcpy(out, in, length);
118 sg_init_one(sg, out, length);
119
120 skcipher_request_set_sync_tfm(req, tfm);
121 skcipher_request_set_callback(req, 0, NULL, NULL);
122 skcipher_request_set_crypt(req, sg, sg, length, local_iv);
123
124 ret = crypto_skcipher_decrypt(req);
125 skcipher_request_zero(req);
126 out:
127 dprintk("RPC: gss_k5decrypt returns %d\n",ret);
128 return ret;
129 }
130
131 static int
checksummer(struct scatterlist * sg,void * data)132 checksummer(struct scatterlist *sg, void *data)
133 {
134 struct ahash_request *req = data;
135
136 ahash_request_set_crypt(req, sg, NULL, sg->length);
137
138 return crypto_ahash_update(req);
139 }
140
141 static int
arcfour_hmac_md5_usage_to_salt(unsigned int usage,u8 salt[4])142 arcfour_hmac_md5_usage_to_salt(unsigned int usage, u8 salt[4])
143 {
144 unsigned int ms_usage;
145
146 switch (usage) {
147 case KG_USAGE_SIGN:
148 ms_usage = 15;
149 break;
150 case KG_USAGE_SEAL:
151 ms_usage = 13;
152 break;
153 default:
154 return -EINVAL;
155 }
156 salt[0] = (ms_usage >> 0) & 0xff;
157 salt[1] = (ms_usage >> 8) & 0xff;
158 salt[2] = (ms_usage >> 16) & 0xff;
159 salt[3] = (ms_usage >> 24) & 0xff;
160
161 return 0;
162 }
163
164 static u32
make_checksum_hmac_md5(struct krb5_ctx * kctx,char * header,int hdrlen,struct xdr_buf * body,int body_offset,u8 * cksumkey,unsigned int usage,struct xdr_netobj * cksumout)165 make_checksum_hmac_md5(struct krb5_ctx *kctx, char *header, int hdrlen,
166 struct xdr_buf *body, int body_offset, u8 *cksumkey,
167 unsigned int usage, struct xdr_netobj *cksumout)
168 {
169 struct scatterlist sg[1];
170 int err = -1;
171 u8 *checksumdata;
172 u8 *rc4salt;
173 struct crypto_ahash *md5;
174 struct crypto_ahash *hmac_md5;
175 struct ahash_request *req;
176
177 if (cksumkey == NULL)
178 return GSS_S_FAILURE;
179
180 if (cksumout->len < kctx->gk5e->cksumlength) {
181 dprintk("%s: checksum buffer length, %u, too small for %s\n",
182 __func__, cksumout->len, kctx->gk5e->name);
183 return GSS_S_FAILURE;
184 }
185
186 rc4salt = kmalloc_array(4, sizeof(*rc4salt), GFP_NOFS);
187 if (!rc4salt)
188 return GSS_S_FAILURE;
189
190 if (arcfour_hmac_md5_usage_to_salt(usage, rc4salt)) {
191 dprintk("%s: invalid usage value %u\n", __func__, usage);
192 goto out_free_rc4salt;
193 }
194
195 checksumdata = kmalloc(GSS_KRB5_MAX_CKSUM_LEN, GFP_NOFS);
196 if (!checksumdata)
197 goto out_free_rc4salt;
198
199 md5 = crypto_alloc_ahash("md5", 0, CRYPTO_ALG_ASYNC);
200 if (IS_ERR(md5))
201 goto out_free_cksum;
202
203 hmac_md5 = crypto_alloc_ahash(kctx->gk5e->cksum_name, 0,
204 CRYPTO_ALG_ASYNC);
205 if (IS_ERR(hmac_md5))
206 goto out_free_md5;
207
208 req = ahash_request_alloc(md5, GFP_NOFS);
209 if (!req)
210 goto out_free_hmac_md5;
211
212 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
213
214 err = crypto_ahash_init(req);
215 if (err)
216 goto out;
217 sg_init_one(sg, rc4salt, 4);
218 ahash_request_set_crypt(req, sg, NULL, 4);
219 err = crypto_ahash_update(req);
220 if (err)
221 goto out;
222
223 sg_init_one(sg, header, hdrlen);
224 ahash_request_set_crypt(req, sg, NULL, hdrlen);
225 err = crypto_ahash_update(req);
226 if (err)
227 goto out;
228 err = xdr_process_buf(body, body_offset, body->len - body_offset,
229 checksummer, req);
230 if (err)
231 goto out;
232 ahash_request_set_crypt(req, NULL, checksumdata, 0);
233 err = crypto_ahash_final(req);
234 if (err)
235 goto out;
236
237 ahash_request_free(req);
238 req = ahash_request_alloc(hmac_md5, GFP_NOFS);
239 if (!req)
240 goto out_free_hmac_md5;
241
242 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
243
244 err = crypto_ahash_setkey(hmac_md5, cksumkey, kctx->gk5e->keylength);
245 if (err)
246 goto out;
247
248 sg_init_one(sg, checksumdata, crypto_ahash_digestsize(md5));
249 ahash_request_set_crypt(req, sg, checksumdata,
250 crypto_ahash_digestsize(md5));
251 err = crypto_ahash_digest(req);
252 if (err)
253 goto out;
254
255 memcpy(cksumout->data, checksumdata, kctx->gk5e->cksumlength);
256 cksumout->len = kctx->gk5e->cksumlength;
257 out:
258 ahash_request_free(req);
259 out_free_hmac_md5:
260 crypto_free_ahash(hmac_md5);
261 out_free_md5:
262 crypto_free_ahash(md5);
263 out_free_cksum:
264 kfree(checksumdata);
265 out_free_rc4salt:
266 kfree(rc4salt);
267 return err ? GSS_S_FAILURE : 0;
268 }
269
270 /*
271 * checksum the plaintext data and hdrlen bytes of the token header
272 * The checksum is performed over the first 8 bytes of the
273 * gss token header and then over the data body
274 */
275 u32
make_checksum(struct krb5_ctx * kctx,char * header,int hdrlen,struct xdr_buf * body,int body_offset,u8 * cksumkey,unsigned int usage,struct xdr_netobj * cksumout)276 make_checksum(struct krb5_ctx *kctx, char *header, int hdrlen,
277 struct xdr_buf *body, int body_offset, u8 *cksumkey,
278 unsigned int usage, struct xdr_netobj *cksumout)
279 {
280 struct crypto_ahash *tfm;
281 struct ahash_request *req;
282 struct scatterlist sg[1];
283 int err = -1;
284 u8 *checksumdata;
285 unsigned int checksumlen;
286
287 if (kctx->gk5e->ctype == CKSUMTYPE_HMAC_MD5_ARCFOUR)
288 return make_checksum_hmac_md5(kctx, header, hdrlen,
289 body, body_offset,
290 cksumkey, usage, cksumout);
291
292 if (cksumout->len < kctx->gk5e->cksumlength) {
293 dprintk("%s: checksum buffer length, %u, too small for %s\n",
294 __func__, cksumout->len, kctx->gk5e->name);
295 return GSS_S_FAILURE;
296 }
297
298 checksumdata = kmalloc(GSS_KRB5_MAX_CKSUM_LEN, GFP_NOFS);
299 if (checksumdata == NULL)
300 return GSS_S_FAILURE;
301
302 tfm = crypto_alloc_ahash(kctx->gk5e->cksum_name, 0, CRYPTO_ALG_ASYNC);
303 if (IS_ERR(tfm))
304 goto out_free_cksum;
305
306 req = ahash_request_alloc(tfm, GFP_NOFS);
307 if (!req)
308 goto out_free_ahash;
309
310 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
311
312 checksumlen = crypto_ahash_digestsize(tfm);
313
314 if (cksumkey != NULL) {
315 err = crypto_ahash_setkey(tfm, cksumkey,
316 kctx->gk5e->keylength);
317 if (err)
318 goto out;
319 }
320
321 err = crypto_ahash_init(req);
322 if (err)
323 goto out;
324 sg_init_one(sg, header, hdrlen);
325 ahash_request_set_crypt(req, sg, NULL, hdrlen);
326 err = crypto_ahash_update(req);
327 if (err)
328 goto out;
329 err = xdr_process_buf(body, body_offset, body->len - body_offset,
330 checksummer, req);
331 if (err)
332 goto out;
333 ahash_request_set_crypt(req, NULL, checksumdata, 0);
334 err = crypto_ahash_final(req);
335 if (err)
336 goto out;
337
338 switch (kctx->gk5e->ctype) {
339 case CKSUMTYPE_RSA_MD5:
340 err = kctx->gk5e->encrypt(kctx->seq, NULL, checksumdata,
341 checksumdata, checksumlen);
342 if (err)
343 goto out;
344 memcpy(cksumout->data,
345 checksumdata + checksumlen - kctx->gk5e->cksumlength,
346 kctx->gk5e->cksumlength);
347 break;
348 case CKSUMTYPE_HMAC_SHA1_DES3:
349 memcpy(cksumout->data, checksumdata, kctx->gk5e->cksumlength);
350 break;
351 default:
352 BUG();
353 break;
354 }
355 cksumout->len = kctx->gk5e->cksumlength;
356 out:
357 ahash_request_free(req);
358 out_free_ahash:
359 crypto_free_ahash(tfm);
360 out_free_cksum:
361 kfree(checksumdata);
362 return err ? GSS_S_FAILURE : 0;
363 }
364
365 /*
366 * checksum the plaintext data and hdrlen bytes of the token header
367 * Per rfc4121, sec. 4.2.4, the checksum is performed over the data
368 * body then over the first 16 octets of the MIC token
369 * Inclusion of the header data in the calculation of the
370 * checksum is optional.
371 */
372 u32
make_checksum_v2(struct krb5_ctx * kctx,char * header,int hdrlen,struct xdr_buf * body,int body_offset,u8 * cksumkey,unsigned int usage,struct xdr_netobj * cksumout)373 make_checksum_v2(struct krb5_ctx *kctx, char *header, int hdrlen,
374 struct xdr_buf *body, int body_offset, u8 *cksumkey,
375 unsigned int usage, struct xdr_netobj *cksumout)
376 {
377 struct crypto_ahash *tfm;
378 struct ahash_request *req;
379 struct scatterlist sg[1];
380 int err = -1;
381 u8 *checksumdata;
382
383 if (kctx->gk5e->keyed_cksum == 0) {
384 dprintk("%s: expected keyed hash for %s\n",
385 __func__, kctx->gk5e->name);
386 return GSS_S_FAILURE;
387 }
388 if (cksumkey == NULL) {
389 dprintk("%s: no key supplied for %s\n",
390 __func__, kctx->gk5e->name);
391 return GSS_S_FAILURE;
392 }
393
394 checksumdata = kmalloc(GSS_KRB5_MAX_CKSUM_LEN, GFP_NOFS);
395 if (!checksumdata)
396 return GSS_S_FAILURE;
397
398 tfm = crypto_alloc_ahash(kctx->gk5e->cksum_name, 0, CRYPTO_ALG_ASYNC);
399 if (IS_ERR(tfm))
400 goto out_free_cksum;
401
402 req = ahash_request_alloc(tfm, GFP_NOFS);
403 if (!req)
404 goto out_free_ahash;
405
406 ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_SLEEP, NULL, NULL);
407
408 err = crypto_ahash_setkey(tfm, cksumkey, kctx->gk5e->keylength);
409 if (err)
410 goto out;
411
412 err = crypto_ahash_init(req);
413 if (err)
414 goto out;
415 err = xdr_process_buf(body, body_offset, body->len - body_offset,
416 checksummer, req);
417 if (err)
418 goto out;
419 if (header != NULL) {
420 sg_init_one(sg, header, hdrlen);
421 ahash_request_set_crypt(req, sg, NULL, hdrlen);
422 err = crypto_ahash_update(req);
423 if (err)
424 goto out;
425 }
426 ahash_request_set_crypt(req, NULL, checksumdata, 0);
427 err = crypto_ahash_final(req);
428 if (err)
429 goto out;
430
431 cksumout->len = kctx->gk5e->cksumlength;
432
433 switch (kctx->gk5e->ctype) {
434 case CKSUMTYPE_HMAC_SHA1_96_AES128:
435 case CKSUMTYPE_HMAC_SHA1_96_AES256:
436 /* note that this truncates the hash */
437 memcpy(cksumout->data, checksumdata, kctx->gk5e->cksumlength);
438 break;
439 default:
440 BUG();
441 break;
442 }
443 out:
444 ahash_request_free(req);
445 out_free_ahash:
446 crypto_free_ahash(tfm);
447 out_free_cksum:
448 kfree(checksumdata);
449 return err ? GSS_S_FAILURE : 0;
450 }
451
452 struct encryptor_desc {
453 u8 iv[GSS_KRB5_MAX_BLOCKSIZE];
454 struct skcipher_request *req;
455 int pos;
456 struct xdr_buf *outbuf;
457 struct page **pages;
458 struct scatterlist infrags[4];
459 struct scatterlist outfrags[4];
460 int fragno;
461 int fraglen;
462 };
463
464 static int
encryptor(struct scatterlist * sg,void * data)465 encryptor(struct scatterlist *sg, void *data)
466 {
467 struct encryptor_desc *desc = data;
468 struct xdr_buf *outbuf = desc->outbuf;
469 struct crypto_sync_skcipher *tfm =
470 crypto_sync_skcipher_reqtfm(desc->req);
471 struct page *in_page;
472 int thislen = desc->fraglen + sg->length;
473 int fraglen, ret;
474 int page_pos;
475
476 /* Worst case is 4 fragments: head, end of page 1, start
477 * of page 2, tail. Anything more is a bug. */
478 BUG_ON(desc->fragno > 3);
479
480 page_pos = desc->pos - outbuf->head[0].iov_len;
481 if (page_pos >= 0 && page_pos < outbuf->page_len) {
482 /* pages are not in place: */
483 int i = (page_pos + outbuf->page_base) >> PAGE_SHIFT;
484 in_page = desc->pages[i];
485 } else {
486 in_page = sg_page(sg);
487 }
488 sg_set_page(&desc->infrags[desc->fragno], in_page, sg->length,
489 sg->offset);
490 sg_set_page(&desc->outfrags[desc->fragno], sg_page(sg), sg->length,
491 sg->offset);
492 desc->fragno++;
493 desc->fraglen += sg->length;
494 desc->pos += sg->length;
495
496 fraglen = thislen & (crypto_sync_skcipher_blocksize(tfm) - 1);
497 thislen -= fraglen;
498
499 if (thislen == 0)
500 return 0;
501
502 sg_mark_end(&desc->infrags[desc->fragno - 1]);
503 sg_mark_end(&desc->outfrags[desc->fragno - 1]);
504
505 skcipher_request_set_crypt(desc->req, desc->infrags, desc->outfrags,
506 thislen, desc->iv);
507
508 ret = crypto_skcipher_encrypt(desc->req);
509 if (ret)
510 return ret;
511
512 sg_init_table(desc->infrags, 4);
513 sg_init_table(desc->outfrags, 4);
514
515 if (fraglen) {
516 sg_set_page(&desc->outfrags[0], sg_page(sg), fraglen,
517 sg->offset + sg->length - fraglen);
518 desc->infrags[0] = desc->outfrags[0];
519 sg_assign_page(&desc->infrags[0], in_page);
520 desc->fragno = 1;
521 desc->fraglen = fraglen;
522 } else {
523 desc->fragno = 0;
524 desc->fraglen = 0;
525 }
526 return 0;
527 }
528
529 int
gss_encrypt_xdr_buf(struct crypto_sync_skcipher * tfm,struct xdr_buf * buf,int offset,struct page ** pages)530 gss_encrypt_xdr_buf(struct crypto_sync_skcipher *tfm, struct xdr_buf *buf,
531 int offset, struct page **pages)
532 {
533 int ret;
534 struct encryptor_desc desc;
535 SYNC_SKCIPHER_REQUEST_ON_STACK(req, tfm);
536
537 BUG_ON((buf->len - offset) % crypto_sync_skcipher_blocksize(tfm) != 0);
538
539 skcipher_request_set_sync_tfm(req, tfm);
540 skcipher_request_set_callback(req, 0, NULL, NULL);
541
542 memset(desc.iv, 0, sizeof(desc.iv));
543 desc.req = req;
544 desc.pos = offset;
545 desc.outbuf = buf;
546 desc.pages = pages;
547 desc.fragno = 0;
548 desc.fraglen = 0;
549
550 sg_init_table(desc.infrags, 4);
551 sg_init_table(desc.outfrags, 4);
552
553 ret = xdr_process_buf(buf, offset, buf->len - offset, encryptor, &desc);
554 skcipher_request_zero(req);
555 return ret;
556 }
557
558 struct decryptor_desc {
559 u8 iv[GSS_KRB5_MAX_BLOCKSIZE];
560 struct skcipher_request *req;
561 struct scatterlist frags[4];
562 int fragno;
563 int fraglen;
564 };
565
566 static int
decryptor(struct scatterlist * sg,void * data)567 decryptor(struct scatterlist *sg, void *data)
568 {
569 struct decryptor_desc *desc = data;
570 int thislen = desc->fraglen + sg->length;
571 struct crypto_sync_skcipher *tfm =
572 crypto_sync_skcipher_reqtfm(desc->req);
573 int fraglen, ret;
574
575 /* Worst case is 4 fragments: head, end of page 1, start
576 * of page 2, tail. Anything more is a bug. */
577 BUG_ON(desc->fragno > 3);
578 sg_set_page(&desc->frags[desc->fragno], sg_page(sg), sg->length,
579 sg->offset);
580 desc->fragno++;
581 desc->fraglen += sg->length;
582
583 fraglen = thislen & (crypto_sync_skcipher_blocksize(tfm) - 1);
584 thislen -= fraglen;
585
586 if (thislen == 0)
587 return 0;
588
589 sg_mark_end(&desc->frags[desc->fragno - 1]);
590
591 skcipher_request_set_crypt(desc->req, desc->frags, desc->frags,
592 thislen, desc->iv);
593
594 ret = crypto_skcipher_decrypt(desc->req);
595 if (ret)
596 return ret;
597
598 sg_init_table(desc->frags, 4);
599
600 if (fraglen) {
601 sg_set_page(&desc->frags[0], sg_page(sg), fraglen,
602 sg->offset + sg->length - fraglen);
603 desc->fragno = 1;
604 desc->fraglen = fraglen;
605 } else {
606 desc->fragno = 0;
607 desc->fraglen = 0;
608 }
609 return 0;
610 }
611
612 int
gss_decrypt_xdr_buf(struct crypto_sync_skcipher * tfm,struct xdr_buf * buf,int offset)613 gss_decrypt_xdr_buf(struct crypto_sync_skcipher *tfm, struct xdr_buf *buf,
614 int offset)
615 {
616 int ret;
617 struct decryptor_desc desc;
618 SYNC_SKCIPHER_REQUEST_ON_STACK(req, tfm);
619
620 /* XXXJBF: */
621 BUG_ON((buf->len - offset) % crypto_sync_skcipher_blocksize(tfm) != 0);
622
623 skcipher_request_set_sync_tfm(req, tfm);
624 skcipher_request_set_callback(req, 0, NULL, NULL);
625
626 memset(desc.iv, 0, sizeof(desc.iv));
627 desc.req = req;
628 desc.fragno = 0;
629 desc.fraglen = 0;
630
631 sg_init_table(desc.frags, 4);
632
633 ret = xdr_process_buf(buf, offset, buf->len - offset, decryptor, &desc);
634 skcipher_request_zero(req);
635 return ret;
636 }
637
638 /*
639 * This function makes the assumption that it was ultimately called
640 * from gss_wrap().
641 *
642 * The client auth_gss code moves any existing tail data into a
643 * separate page before calling gss_wrap.
644 * The server svcauth_gss code ensures that both the head and the
645 * tail have slack space of RPC_MAX_AUTH_SIZE before calling gss_wrap.
646 *
647 * Even with that guarantee, this function may be called more than
648 * once in the processing of gss_wrap(). The best we can do is
649 * verify at compile-time (see GSS_KRB5_SLACK_CHECK) that the
650 * largest expected shift will fit within RPC_MAX_AUTH_SIZE.
651 * At run-time we can verify that a single invocation of this
652 * function doesn't attempt to use more the RPC_MAX_AUTH_SIZE.
653 */
654
655 int
xdr_extend_head(struct xdr_buf * buf,unsigned int base,unsigned int shiftlen)656 xdr_extend_head(struct xdr_buf *buf, unsigned int base, unsigned int shiftlen)
657 {
658 u8 *p;
659
660 if (shiftlen == 0)
661 return 0;
662
663 BUILD_BUG_ON(GSS_KRB5_MAX_SLACK_NEEDED > RPC_MAX_AUTH_SIZE);
664 BUG_ON(shiftlen > RPC_MAX_AUTH_SIZE);
665
666 p = buf->head[0].iov_base + base;
667
668 memmove(p + shiftlen, p, buf->head[0].iov_len - base);
669
670 buf->head[0].iov_len += shiftlen;
671 buf->len += shiftlen;
672
673 return 0;
674 }
675
676 static u32
gss_krb5_cts_crypt(struct crypto_sync_skcipher * cipher,struct xdr_buf * buf,u32 offset,u8 * iv,struct page ** pages,int encrypt)677 gss_krb5_cts_crypt(struct crypto_sync_skcipher *cipher, struct xdr_buf *buf,
678 u32 offset, u8 *iv, struct page **pages, int encrypt)
679 {
680 u32 ret;
681 struct scatterlist sg[1];
682 SYNC_SKCIPHER_REQUEST_ON_STACK(req, cipher);
683 u8 *data;
684 struct page **save_pages;
685 u32 len = buf->len - offset;
686
687 if (len > GSS_KRB5_MAX_BLOCKSIZE * 2) {
688 WARN_ON(0);
689 return -ENOMEM;
690 }
691 data = kmalloc(GSS_KRB5_MAX_BLOCKSIZE * 2, GFP_NOFS);
692 if (!data)
693 return -ENOMEM;
694
695 /*
696 * For encryption, we want to read from the cleartext
697 * page cache pages, and write the encrypted data to
698 * the supplied xdr_buf pages.
699 */
700 save_pages = buf->pages;
701 if (encrypt)
702 buf->pages = pages;
703
704 ret = read_bytes_from_xdr_buf(buf, offset, data, len);
705 buf->pages = save_pages;
706 if (ret)
707 goto out;
708
709 sg_init_one(sg, data, len);
710
711 skcipher_request_set_sync_tfm(req, cipher);
712 skcipher_request_set_callback(req, 0, NULL, NULL);
713 skcipher_request_set_crypt(req, sg, sg, len, iv);
714
715 if (encrypt)
716 ret = crypto_skcipher_encrypt(req);
717 else
718 ret = crypto_skcipher_decrypt(req);
719
720 skcipher_request_zero(req);
721
722 if (ret)
723 goto out;
724
725 ret = write_bytes_to_xdr_buf(buf, offset, data, len);
726
727 out:
728 kfree(data);
729 return ret;
730 }
731
732 u32
gss_krb5_aes_encrypt(struct krb5_ctx * kctx,u32 offset,struct xdr_buf * buf,struct page ** pages)733 gss_krb5_aes_encrypt(struct krb5_ctx *kctx, u32 offset,
734 struct xdr_buf *buf, struct page **pages)
735 {
736 u32 err;
737 struct xdr_netobj hmac;
738 u8 *cksumkey;
739 u8 *ecptr;
740 struct crypto_sync_skcipher *cipher, *aux_cipher;
741 int blocksize;
742 struct page **save_pages;
743 int nblocks, nbytes;
744 struct encryptor_desc desc;
745 u32 cbcbytes;
746 unsigned int usage;
747
748 if (kctx->initiate) {
749 cipher = kctx->initiator_enc;
750 aux_cipher = kctx->initiator_enc_aux;
751 cksumkey = kctx->initiator_integ;
752 usage = KG_USAGE_INITIATOR_SEAL;
753 } else {
754 cipher = kctx->acceptor_enc;
755 aux_cipher = kctx->acceptor_enc_aux;
756 cksumkey = kctx->acceptor_integ;
757 usage = KG_USAGE_ACCEPTOR_SEAL;
758 }
759 blocksize = crypto_sync_skcipher_blocksize(cipher);
760
761 /* hide the gss token header and insert the confounder */
762 offset += GSS_KRB5_TOK_HDR_LEN;
763 if (xdr_extend_head(buf, offset, kctx->gk5e->conflen))
764 return GSS_S_FAILURE;
765 gss_krb5_make_confounder(buf->head[0].iov_base + offset, kctx->gk5e->conflen);
766 offset -= GSS_KRB5_TOK_HDR_LEN;
767
768 if (buf->tail[0].iov_base != NULL) {
769 ecptr = buf->tail[0].iov_base + buf->tail[0].iov_len;
770 } else {
771 buf->tail[0].iov_base = buf->head[0].iov_base
772 + buf->head[0].iov_len;
773 buf->tail[0].iov_len = 0;
774 ecptr = buf->tail[0].iov_base;
775 }
776
777 /* copy plaintext gss token header after filler (if any) */
778 memcpy(ecptr, buf->head[0].iov_base + offset, GSS_KRB5_TOK_HDR_LEN);
779 buf->tail[0].iov_len += GSS_KRB5_TOK_HDR_LEN;
780 buf->len += GSS_KRB5_TOK_HDR_LEN;
781
782 /* Do the HMAC */
783 hmac.len = GSS_KRB5_MAX_CKSUM_LEN;
784 hmac.data = buf->tail[0].iov_base + buf->tail[0].iov_len;
785
786 /*
787 * When we are called, pages points to the real page cache
788 * data -- which we can't go and encrypt! buf->pages points
789 * to scratch pages which we are going to send off to the
790 * client/server. Swap in the plaintext pages to calculate
791 * the hmac.
792 */
793 save_pages = buf->pages;
794 buf->pages = pages;
795
796 err = make_checksum_v2(kctx, NULL, 0, buf,
797 offset + GSS_KRB5_TOK_HDR_LEN,
798 cksumkey, usage, &hmac);
799 buf->pages = save_pages;
800 if (err)
801 return GSS_S_FAILURE;
802
803 nbytes = buf->len - offset - GSS_KRB5_TOK_HDR_LEN;
804 nblocks = (nbytes + blocksize - 1) / blocksize;
805 cbcbytes = 0;
806 if (nblocks > 2)
807 cbcbytes = (nblocks - 2) * blocksize;
808
809 memset(desc.iv, 0, sizeof(desc.iv));
810
811 if (cbcbytes) {
812 SYNC_SKCIPHER_REQUEST_ON_STACK(req, aux_cipher);
813
814 desc.pos = offset + GSS_KRB5_TOK_HDR_LEN;
815 desc.fragno = 0;
816 desc.fraglen = 0;
817 desc.pages = pages;
818 desc.outbuf = buf;
819 desc.req = req;
820
821 skcipher_request_set_sync_tfm(req, aux_cipher);
822 skcipher_request_set_callback(req, 0, NULL, NULL);
823
824 sg_init_table(desc.infrags, 4);
825 sg_init_table(desc.outfrags, 4);
826
827 err = xdr_process_buf(buf, offset + GSS_KRB5_TOK_HDR_LEN,
828 cbcbytes, encryptor, &desc);
829 skcipher_request_zero(req);
830 if (err)
831 goto out_err;
832 }
833
834 /* Make sure IV carries forward from any CBC results. */
835 err = gss_krb5_cts_crypt(cipher, buf,
836 offset + GSS_KRB5_TOK_HDR_LEN + cbcbytes,
837 desc.iv, pages, 1);
838 if (err) {
839 err = GSS_S_FAILURE;
840 goto out_err;
841 }
842
843 /* Now update buf to account for HMAC */
844 buf->tail[0].iov_len += kctx->gk5e->cksumlength;
845 buf->len += kctx->gk5e->cksumlength;
846
847 out_err:
848 if (err)
849 err = GSS_S_FAILURE;
850 return err;
851 }
852
853 u32
gss_krb5_aes_decrypt(struct krb5_ctx * kctx,u32 offset,struct xdr_buf * buf,u32 * headskip,u32 * tailskip)854 gss_krb5_aes_decrypt(struct krb5_ctx *kctx, u32 offset, struct xdr_buf *buf,
855 u32 *headskip, u32 *tailskip)
856 {
857 struct xdr_buf subbuf;
858 u32 ret = 0;
859 u8 *cksum_key;
860 struct crypto_sync_skcipher *cipher, *aux_cipher;
861 struct xdr_netobj our_hmac_obj;
862 u8 our_hmac[GSS_KRB5_MAX_CKSUM_LEN];
863 u8 pkt_hmac[GSS_KRB5_MAX_CKSUM_LEN];
864 int nblocks, blocksize, cbcbytes;
865 struct decryptor_desc desc;
866 unsigned int usage;
867
868 if (kctx->initiate) {
869 cipher = kctx->acceptor_enc;
870 aux_cipher = kctx->acceptor_enc_aux;
871 cksum_key = kctx->acceptor_integ;
872 usage = KG_USAGE_ACCEPTOR_SEAL;
873 } else {
874 cipher = kctx->initiator_enc;
875 aux_cipher = kctx->initiator_enc_aux;
876 cksum_key = kctx->initiator_integ;
877 usage = KG_USAGE_INITIATOR_SEAL;
878 }
879 blocksize = crypto_sync_skcipher_blocksize(cipher);
880
881
882 /* create a segment skipping the header and leaving out the checksum */
883 xdr_buf_subsegment(buf, &subbuf, offset + GSS_KRB5_TOK_HDR_LEN,
884 (buf->len - offset - GSS_KRB5_TOK_HDR_LEN -
885 kctx->gk5e->cksumlength));
886
887 nblocks = (subbuf.len + blocksize - 1) / blocksize;
888
889 cbcbytes = 0;
890 if (nblocks > 2)
891 cbcbytes = (nblocks - 2) * blocksize;
892
893 memset(desc.iv, 0, sizeof(desc.iv));
894
895 if (cbcbytes) {
896 SYNC_SKCIPHER_REQUEST_ON_STACK(req, aux_cipher);
897
898 desc.fragno = 0;
899 desc.fraglen = 0;
900 desc.req = req;
901
902 skcipher_request_set_sync_tfm(req, aux_cipher);
903 skcipher_request_set_callback(req, 0, NULL, NULL);
904
905 sg_init_table(desc.frags, 4);
906
907 ret = xdr_process_buf(&subbuf, 0, cbcbytes, decryptor, &desc);
908 skcipher_request_zero(req);
909 if (ret)
910 goto out_err;
911 }
912
913 /* Make sure IV carries forward from any CBC results. */
914 ret = gss_krb5_cts_crypt(cipher, &subbuf, cbcbytes, desc.iv, NULL, 0);
915 if (ret)
916 goto out_err;
917
918
919 /* Calculate our hmac over the plaintext data */
920 our_hmac_obj.len = sizeof(our_hmac);
921 our_hmac_obj.data = our_hmac;
922
923 ret = make_checksum_v2(kctx, NULL, 0, &subbuf, 0,
924 cksum_key, usage, &our_hmac_obj);
925 if (ret)
926 goto out_err;
927
928 /* Get the packet's hmac value */
929 ret = read_bytes_from_xdr_buf(buf, buf->len - kctx->gk5e->cksumlength,
930 pkt_hmac, kctx->gk5e->cksumlength);
931 if (ret)
932 goto out_err;
933
934 if (crypto_memneq(pkt_hmac, our_hmac, kctx->gk5e->cksumlength) != 0) {
935 ret = GSS_S_BAD_SIG;
936 goto out_err;
937 }
938 *headskip = kctx->gk5e->conflen;
939 *tailskip = kctx->gk5e->cksumlength;
940 out_err:
941 if (ret && ret != GSS_S_BAD_SIG)
942 ret = GSS_S_FAILURE;
943 return ret;
944 }
945
946 /*
947 * Compute Kseq given the initial session key and the checksum.
948 * Set the key of the given cipher.
949 */
950 int
krb5_rc4_setup_seq_key(struct krb5_ctx * kctx,struct crypto_sync_skcipher * cipher,unsigned char * cksum)951 krb5_rc4_setup_seq_key(struct krb5_ctx *kctx,
952 struct crypto_sync_skcipher *cipher,
953 unsigned char *cksum)
954 {
955 struct crypto_shash *hmac;
956 struct shash_desc *desc;
957 u8 Kseq[GSS_KRB5_MAX_KEYLEN];
958 u32 zeroconstant = 0;
959 int err;
960
961 dprintk("%s: entered\n", __func__);
962
963 hmac = crypto_alloc_shash(kctx->gk5e->cksum_name, 0, 0);
964 if (IS_ERR(hmac)) {
965 dprintk("%s: error %ld, allocating hash '%s'\n",
966 __func__, PTR_ERR(hmac), kctx->gk5e->cksum_name);
967 return PTR_ERR(hmac);
968 }
969
970 desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(hmac),
971 GFP_NOFS);
972 if (!desc) {
973 dprintk("%s: failed to allocate shash descriptor for '%s'\n",
974 __func__, kctx->gk5e->cksum_name);
975 crypto_free_shash(hmac);
976 return -ENOMEM;
977 }
978
979 desc->tfm = hmac;
980
981 /* Compute intermediate Kseq from session key */
982 err = crypto_shash_setkey(hmac, kctx->Ksess, kctx->gk5e->keylength);
983 if (err)
984 goto out_err;
985
986 err = crypto_shash_digest(desc, (u8 *)&zeroconstant, 4, Kseq);
987 if (err)
988 goto out_err;
989
990 /* Compute final Kseq from the checksum and intermediate Kseq */
991 err = crypto_shash_setkey(hmac, Kseq, kctx->gk5e->keylength);
992 if (err)
993 goto out_err;
994
995 err = crypto_shash_digest(desc, cksum, 8, Kseq);
996 if (err)
997 goto out_err;
998
999 err = crypto_sync_skcipher_setkey(cipher, Kseq, kctx->gk5e->keylength);
1000 if (err)
1001 goto out_err;
1002
1003 err = 0;
1004
1005 out_err:
1006 kzfree(desc);
1007 crypto_free_shash(hmac);
1008 dprintk("%s: returning %d\n", __func__, err);
1009 return err;
1010 }
1011
1012 /*
1013 * Compute Kcrypt given the initial session key and the plaintext seqnum.
1014 * Set the key of cipher kctx->enc.
1015 */
1016 int
krb5_rc4_setup_enc_key(struct krb5_ctx * kctx,struct crypto_sync_skcipher * cipher,s32 seqnum)1017 krb5_rc4_setup_enc_key(struct krb5_ctx *kctx,
1018 struct crypto_sync_skcipher *cipher,
1019 s32 seqnum)
1020 {
1021 struct crypto_shash *hmac;
1022 struct shash_desc *desc;
1023 u8 Kcrypt[GSS_KRB5_MAX_KEYLEN];
1024 u8 zeroconstant[4] = {0};
1025 u8 seqnumarray[4];
1026 int err, i;
1027
1028 dprintk("%s: entered, seqnum %u\n", __func__, seqnum);
1029
1030 hmac = crypto_alloc_shash(kctx->gk5e->cksum_name, 0, 0);
1031 if (IS_ERR(hmac)) {
1032 dprintk("%s: error %ld, allocating hash '%s'\n",
1033 __func__, PTR_ERR(hmac), kctx->gk5e->cksum_name);
1034 return PTR_ERR(hmac);
1035 }
1036
1037 desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(hmac),
1038 GFP_NOFS);
1039 if (!desc) {
1040 dprintk("%s: failed to allocate shash descriptor for '%s'\n",
1041 __func__, kctx->gk5e->cksum_name);
1042 crypto_free_shash(hmac);
1043 return -ENOMEM;
1044 }
1045
1046 desc->tfm = hmac;
1047
1048 /* Compute intermediate Kcrypt from session key */
1049 for (i = 0; i < kctx->gk5e->keylength; i++)
1050 Kcrypt[i] = kctx->Ksess[i] ^ 0xf0;
1051
1052 err = crypto_shash_setkey(hmac, Kcrypt, kctx->gk5e->keylength);
1053 if (err)
1054 goto out_err;
1055
1056 err = crypto_shash_digest(desc, zeroconstant, 4, Kcrypt);
1057 if (err)
1058 goto out_err;
1059
1060 /* Compute final Kcrypt from the seqnum and intermediate Kcrypt */
1061 err = crypto_shash_setkey(hmac, Kcrypt, kctx->gk5e->keylength);
1062 if (err)
1063 goto out_err;
1064
1065 seqnumarray[0] = (unsigned char) ((seqnum >> 24) & 0xff);
1066 seqnumarray[1] = (unsigned char) ((seqnum >> 16) & 0xff);
1067 seqnumarray[2] = (unsigned char) ((seqnum >> 8) & 0xff);
1068 seqnumarray[3] = (unsigned char) ((seqnum >> 0) & 0xff);
1069
1070 err = crypto_shash_digest(desc, seqnumarray, 4, Kcrypt);
1071 if (err)
1072 goto out_err;
1073
1074 err = crypto_sync_skcipher_setkey(cipher, Kcrypt,
1075 kctx->gk5e->keylength);
1076 if (err)
1077 goto out_err;
1078
1079 err = 0;
1080
1081 out_err:
1082 kzfree(desc);
1083 crypto_free_shash(hmac);
1084 dprintk("%s: returning %d\n", __func__, err);
1085 return err;
1086 }
1087