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_skcipher * tfm,void * iv,void * in,void * out,int length)55 krb5_encrypt(
56 struct crypto_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 SKCIPHER_REQUEST_ON_STACK(req, tfm);
66
67 if (length % crypto_skcipher_blocksize(tfm) != 0)
68 goto out;
69
70 if (crypto_skcipher_ivsize(tfm) > GSS_KRB5_MAX_BLOCKSIZE) {
71 dprintk("RPC: gss_k5encrypt: tfm iv size too large %d\n",
72 crypto_skcipher_ivsize(tfm));
73 goto out;
74 }
75
76 if (iv)
77 memcpy(local_iv, iv, crypto_skcipher_ivsize(tfm));
78
79 memcpy(out, in, length);
80 sg_init_one(sg, out, length);
81
82 skcipher_request_set_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_skcipher * tfm,void * iv,void * in,void * out,int length)94 krb5_decrypt(
95 struct crypto_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 SKCIPHER_REQUEST_ON_STACK(req, tfm);
105
106 if (length % crypto_skcipher_blocksize(tfm) != 0)
107 goto out;
108
109 if (crypto_skcipher_ivsize(tfm) > GSS_KRB5_MAX_BLOCKSIZE) {
110 dprintk("RPC: gss_k5decrypt: tfm iv size too large %d\n",
111 crypto_skcipher_ivsize(tfm));
112 goto out;
113 }
114 if (iv)
115 memcpy(local_iv,iv, crypto_skcipher_ivsize(tfm));
116
117 memcpy(out, in, length);
118 sg_init_one(sg, out, length);
119
120 skcipher_request_set_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_skcipher *tfm = crypto_skcipher_reqtfm(desc->req);
470 struct page *in_page;
471 int thislen = desc->fraglen + sg->length;
472 int fraglen, ret;
473 int page_pos;
474
475 /* Worst case is 4 fragments: head, end of page 1, start
476 * of page 2, tail. Anything more is a bug. */
477 BUG_ON(desc->fragno > 3);
478
479 page_pos = desc->pos - outbuf->head[0].iov_len;
480 if (page_pos >= 0 && page_pos < outbuf->page_len) {
481 /* pages are not in place: */
482 int i = (page_pos + outbuf->page_base) >> PAGE_SHIFT;
483 in_page = desc->pages[i];
484 } else {
485 in_page = sg_page(sg);
486 }
487 sg_set_page(&desc->infrags[desc->fragno], in_page, sg->length,
488 sg->offset);
489 sg_set_page(&desc->outfrags[desc->fragno], sg_page(sg), sg->length,
490 sg->offset);
491 desc->fragno++;
492 desc->fraglen += sg->length;
493 desc->pos += sg->length;
494
495 fraglen = thislen & (crypto_skcipher_blocksize(tfm) - 1);
496 thislen -= fraglen;
497
498 if (thislen == 0)
499 return 0;
500
501 sg_mark_end(&desc->infrags[desc->fragno - 1]);
502 sg_mark_end(&desc->outfrags[desc->fragno - 1]);
503
504 skcipher_request_set_crypt(desc->req, desc->infrags, desc->outfrags,
505 thislen, desc->iv);
506
507 ret = crypto_skcipher_encrypt(desc->req);
508 if (ret)
509 return ret;
510
511 sg_init_table(desc->infrags, 4);
512 sg_init_table(desc->outfrags, 4);
513
514 if (fraglen) {
515 sg_set_page(&desc->outfrags[0], sg_page(sg), fraglen,
516 sg->offset + sg->length - fraglen);
517 desc->infrags[0] = desc->outfrags[0];
518 sg_assign_page(&desc->infrags[0], in_page);
519 desc->fragno = 1;
520 desc->fraglen = fraglen;
521 } else {
522 desc->fragno = 0;
523 desc->fraglen = 0;
524 }
525 return 0;
526 }
527
528 int
gss_encrypt_xdr_buf(struct crypto_skcipher * tfm,struct xdr_buf * buf,int offset,struct page ** pages)529 gss_encrypt_xdr_buf(struct crypto_skcipher *tfm, struct xdr_buf *buf,
530 int offset, struct page **pages)
531 {
532 int ret;
533 struct encryptor_desc desc;
534 SKCIPHER_REQUEST_ON_STACK(req, tfm);
535
536 BUG_ON((buf->len - offset) % crypto_skcipher_blocksize(tfm) != 0);
537
538 skcipher_request_set_tfm(req, tfm);
539 skcipher_request_set_callback(req, 0, NULL, NULL);
540
541 memset(desc.iv, 0, sizeof(desc.iv));
542 desc.req = req;
543 desc.pos = offset;
544 desc.outbuf = buf;
545 desc.pages = pages;
546 desc.fragno = 0;
547 desc.fraglen = 0;
548
549 sg_init_table(desc.infrags, 4);
550 sg_init_table(desc.outfrags, 4);
551
552 ret = xdr_process_buf(buf, offset, buf->len - offset, encryptor, &desc);
553 skcipher_request_zero(req);
554 return ret;
555 }
556
557 struct decryptor_desc {
558 u8 iv[GSS_KRB5_MAX_BLOCKSIZE];
559 struct skcipher_request *req;
560 struct scatterlist frags[4];
561 int fragno;
562 int fraglen;
563 };
564
565 static int
decryptor(struct scatterlist * sg,void * data)566 decryptor(struct scatterlist *sg, void *data)
567 {
568 struct decryptor_desc *desc = data;
569 int thislen = desc->fraglen + sg->length;
570 struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(desc->req);
571 int fraglen, ret;
572
573 /* Worst case is 4 fragments: head, end of page 1, start
574 * of page 2, tail. Anything more is a bug. */
575 BUG_ON(desc->fragno > 3);
576 sg_set_page(&desc->frags[desc->fragno], sg_page(sg), sg->length,
577 sg->offset);
578 desc->fragno++;
579 desc->fraglen += sg->length;
580
581 fraglen = thislen & (crypto_skcipher_blocksize(tfm) - 1);
582 thislen -= fraglen;
583
584 if (thislen == 0)
585 return 0;
586
587 sg_mark_end(&desc->frags[desc->fragno - 1]);
588
589 skcipher_request_set_crypt(desc->req, desc->frags, desc->frags,
590 thislen, desc->iv);
591
592 ret = crypto_skcipher_decrypt(desc->req);
593 if (ret)
594 return ret;
595
596 sg_init_table(desc->frags, 4);
597
598 if (fraglen) {
599 sg_set_page(&desc->frags[0], sg_page(sg), fraglen,
600 sg->offset + sg->length - fraglen);
601 desc->fragno = 1;
602 desc->fraglen = fraglen;
603 } else {
604 desc->fragno = 0;
605 desc->fraglen = 0;
606 }
607 return 0;
608 }
609
610 int
gss_decrypt_xdr_buf(struct crypto_skcipher * tfm,struct xdr_buf * buf,int offset)611 gss_decrypt_xdr_buf(struct crypto_skcipher *tfm, struct xdr_buf *buf,
612 int offset)
613 {
614 int ret;
615 struct decryptor_desc desc;
616 SKCIPHER_REQUEST_ON_STACK(req, tfm);
617
618 /* XXXJBF: */
619 BUG_ON((buf->len - offset) % crypto_skcipher_blocksize(tfm) != 0);
620
621 skcipher_request_set_tfm(req, tfm);
622 skcipher_request_set_callback(req, 0, NULL, NULL);
623
624 memset(desc.iv, 0, sizeof(desc.iv));
625 desc.req = req;
626 desc.fragno = 0;
627 desc.fraglen = 0;
628
629 sg_init_table(desc.frags, 4);
630
631 ret = xdr_process_buf(buf, offset, buf->len - offset, decryptor, &desc);
632 skcipher_request_zero(req);
633 return ret;
634 }
635
636 /*
637 * This function makes the assumption that it was ultimately called
638 * from gss_wrap().
639 *
640 * The client auth_gss code moves any existing tail data into a
641 * separate page before calling gss_wrap.
642 * The server svcauth_gss code ensures that both the head and the
643 * tail have slack space of RPC_MAX_AUTH_SIZE before calling gss_wrap.
644 *
645 * Even with that guarantee, this function may be called more than
646 * once in the processing of gss_wrap(). The best we can do is
647 * verify at compile-time (see GSS_KRB5_SLACK_CHECK) that the
648 * largest expected shift will fit within RPC_MAX_AUTH_SIZE.
649 * At run-time we can verify that a single invocation of this
650 * function doesn't attempt to use more the RPC_MAX_AUTH_SIZE.
651 */
652
653 int
xdr_extend_head(struct xdr_buf * buf,unsigned int base,unsigned int shiftlen)654 xdr_extend_head(struct xdr_buf *buf, unsigned int base, unsigned int shiftlen)
655 {
656 u8 *p;
657
658 if (shiftlen == 0)
659 return 0;
660
661 BUILD_BUG_ON(GSS_KRB5_MAX_SLACK_NEEDED > RPC_MAX_AUTH_SIZE);
662 BUG_ON(shiftlen > RPC_MAX_AUTH_SIZE);
663
664 p = buf->head[0].iov_base + base;
665
666 memmove(p + shiftlen, p, buf->head[0].iov_len - base);
667
668 buf->head[0].iov_len += shiftlen;
669 buf->len += shiftlen;
670
671 return 0;
672 }
673
674 static u32
gss_krb5_cts_crypt(struct crypto_skcipher * cipher,struct xdr_buf * buf,u32 offset,u8 * iv,struct page ** pages,int encrypt)675 gss_krb5_cts_crypt(struct crypto_skcipher *cipher, struct xdr_buf *buf,
676 u32 offset, u8 *iv, struct page **pages, int encrypt)
677 {
678 u32 ret;
679 struct scatterlist sg[1];
680 SKCIPHER_REQUEST_ON_STACK(req, cipher);
681 u8 *data;
682 struct page **save_pages;
683 u32 len = buf->len - offset;
684
685 if (len > GSS_KRB5_MAX_BLOCKSIZE * 2) {
686 WARN_ON(0);
687 return -ENOMEM;
688 }
689 data = kmalloc(GSS_KRB5_MAX_BLOCKSIZE * 2, GFP_NOFS);
690 if (!data)
691 return -ENOMEM;
692
693 /*
694 * For encryption, we want to read from the cleartext
695 * page cache pages, and write the encrypted data to
696 * the supplied xdr_buf pages.
697 */
698 save_pages = buf->pages;
699 if (encrypt)
700 buf->pages = pages;
701
702 ret = read_bytes_from_xdr_buf(buf, offset, data, len);
703 buf->pages = save_pages;
704 if (ret)
705 goto out;
706
707 sg_init_one(sg, data, len);
708
709 skcipher_request_set_tfm(req, cipher);
710 skcipher_request_set_callback(req, 0, NULL, NULL);
711 skcipher_request_set_crypt(req, sg, sg, len, iv);
712
713 if (encrypt)
714 ret = crypto_skcipher_encrypt(req);
715 else
716 ret = crypto_skcipher_decrypt(req);
717
718 skcipher_request_zero(req);
719
720 if (ret)
721 goto out;
722
723 ret = write_bytes_to_xdr_buf(buf, offset, data, len);
724
725 out:
726 kfree(data);
727 return ret;
728 }
729
730 u32
gss_krb5_aes_encrypt(struct krb5_ctx * kctx,u32 offset,struct xdr_buf * buf,struct page ** pages)731 gss_krb5_aes_encrypt(struct krb5_ctx *kctx, u32 offset,
732 struct xdr_buf *buf, struct page **pages)
733 {
734 u32 err;
735 struct xdr_netobj hmac;
736 u8 *cksumkey;
737 u8 *ecptr;
738 struct crypto_skcipher *cipher, *aux_cipher;
739 int blocksize;
740 struct page **save_pages;
741 int nblocks, nbytes;
742 struct encryptor_desc desc;
743 u32 cbcbytes;
744 unsigned int usage;
745
746 if (kctx->initiate) {
747 cipher = kctx->initiator_enc;
748 aux_cipher = kctx->initiator_enc_aux;
749 cksumkey = kctx->initiator_integ;
750 usage = KG_USAGE_INITIATOR_SEAL;
751 } else {
752 cipher = kctx->acceptor_enc;
753 aux_cipher = kctx->acceptor_enc_aux;
754 cksumkey = kctx->acceptor_integ;
755 usage = KG_USAGE_ACCEPTOR_SEAL;
756 }
757 blocksize = crypto_skcipher_blocksize(cipher);
758
759 /* hide the gss token header and insert the confounder */
760 offset += GSS_KRB5_TOK_HDR_LEN;
761 if (xdr_extend_head(buf, offset, kctx->gk5e->conflen))
762 return GSS_S_FAILURE;
763 gss_krb5_make_confounder(buf->head[0].iov_base + offset, kctx->gk5e->conflen);
764 offset -= GSS_KRB5_TOK_HDR_LEN;
765
766 if (buf->tail[0].iov_base != NULL) {
767 ecptr = buf->tail[0].iov_base + buf->tail[0].iov_len;
768 } else {
769 buf->tail[0].iov_base = buf->head[0].iov_base
770 + buf->head[0].iov_len;
771 buf->tail[0].iov_len = 0;
772 ecptr = buf->tail[0].iov_base;
773 }
774
775 /* copy plaintext gss token header after filler (if any) */
776 memcpy(ecptr, buf->head[0].iov_base + offset, GSS_KRB5_TOK_HDR_LEN);
777 buf->tail[0].iov_len += GSS_KRB5_TOK_HDR_LEN;
778 buf->len += GSS_KRB5_TOK_HDR_LEN;
779
780 /* Do the HMAC */
781 hmac.len = GSS_KRB5_MAX_CKSUM_LEN;
782 hmac.data = buf->tail[0].iov_base + buf->tail[0].iov_len;
783
784 /*
785 * When we are called, pages points to the real page cache
786 * data -- which we can't go and encrypt! buf->pages points
787 * to scratch pages which we are going to send off to the
788 * client/server. Swap in the plaintext pages to calculate
789 * the hmac.
790 */
791 save_pages = buf->pages;
792 buf->pages = pages;
793
794 err = make_checksum_v2(kctx, NULL, 0, buf,
795 offset + GSS_KRB5_TOK_HDR_LEN,
796 cksumkey, usage, &hmac);
797 buf->pages = save_pages;
798 if (err)
799 return GSS_S_FAILURE;
800
801 nbytes = buf->len - offset - GSS_KRB5_TOK_HDR_LEN;
802 nblocks = (nbytes + blocksize - 1) / blocksize;
803 cbcbytes = 0;
804 if (nblocks > 2)
805 cbcbytes = (nblocks - 2) * blocksize;
806
807 memset(desc.iv, 0, sizeof(desc.iv));
808
809 if (cbcbytes) {
810 SKCIPHER_REQUEST_ON_STACK(req, aux_cipher);
811
812 desc.pos = offset + GSS_KRB5_TOK_HDR_LEN;
813 desc.fragno = 0;
814 desc.fraglen = 0;
815 desc.pages = pages;
816 desc.outbuf = buf;
817 desc.req = req;
818
819 skcipher_request_set_tfm(req, aux_cipher);
820 skcipher_request_set_callback(req, 0, NULL, NULL);
821
822 sg_init_table(desc.infrags, 4);
823 sg_init_table(desc.outfrags, 4);
824
825 err = xdr_process_buf(buf, offset + GSS_KRB5_TOK_HDR_LEN,
826 cbcbytes, encryptor, &desc);
827 skcipher_request_zero(req);
828 if (err)
829 goto out_err;
830 }
831
832 /* Make sure IV carries forward from any CBC results. */
833 err = gss_krb5_cts_crypt(cipher, buf,
834 offset + GSS_KRB5_TOK_HDR_LEN + cbcbytes,
835 desc.iv, pages, 1);
836 if (err) {
837 err = GSS_S_FAILURE;
838 goto out_err;
839 }
840
841 /* Now update buf to account for HMAC */
842 buf->tail[0].iov_len += kctx->gk5e->cksumlength;
843 buf->len += kctx->gk5e->cksumlength;
844
845 out_err:
846 if (err)
847 err = GSS_S_FAILURE;
848 return err;
849 }
850
851 u32
gss_krb5_aes_decrypt(struct krb5_ctx * kctx,u32 offset,struct xdr_buf * buf,u32 * headskip,u32 * tailskip)852 gss_krb5_aes_decrypt(struct krb5_ctx *kctx, u32 offset, struct xdr_buf *buf,
853 u32 *headskip, u32 *tailskip)
854 {
855 struct xdr_buf subbuf;
856 u32 ret = 0;
857 u8 *cksum_key;
858 struct crypto_skcipher *cipher, *aux_cipher;
859 struct xdr_netobj our_hmac_obj;
860 u8 our_hmac[GSS_KRB5_MAX_CKSUM_LEN];
861 u8 pkt_hmac[GSS_KRB5_MAX_CKSUM_LEN];
862 int nblocks, blocksize, cbcbytes;
863 struct decryptor_desc desc;
864 unsigned int usage;
865
866 if (kctx->initiate) {
867 cipher = kctx->acceptor_enc;
868 aux_cipher = kctx->acceptor_enc_aux;
869 cksum_key = kctx->acceptor_integ;
870 usage = KG_USAGE_ACCEPTOR_SEAL;
871 } else {
872 cipher = kctx->initiator_enc;
873 aux_cipher = kctx->initiator_enc_aux;
874 cksum_key = kctx->initiator_integ;
875 usage = KG_USAGE_INITIATOR_SEAL;
876 }
877 blocksize = crypto_skcipher_blocksize(cipher);
878
879
880 /* create a segment skipping the header and leaving out the checksum */
881 xdr_buf_subsegment(buf, &subbuf, offset + GSS_KRB5_TOK_HDR_LEN,
882 (buf->len - offset - GSS_KRB5_TOK_HDR_LEN -
883 kctx->gk5e->cksumlength));
884
885 nblocks = (subbuf.len + blocksize - 1) / blocksize;
886
887 cbcbytes = 0;
888 if (nblocks > 2)
889 cbcbytes = (nblocks - 2) * blocksize;
890
891 memset(desc.iv, 0, sizeof(desc.iv));
892
893 if (cbcbytes) {
894 SKCIPHER_REQUEST_ON_STACK(req, aux_cipher);
895
896 desc.fragno = 0;
897 desc.fraglen = 0;
898 desc.req = req;
899
900 skcipher_request_set_tfm(req, aux_cipher);
901 skcipher_request_set_callback(req, 0, NULL, NULL);
902
903 sg_init_table(desc.frags, 4);
904
905 ret = xdr_process_buf(&subbuf, 0, cbcbytes, decryptor, &desc);
906 skcipher_request_zero(req);
907 if (ret)
908 goto out_err;
909 }
910
911 /* Make sure IV carries forward from any CBC results. */
912 ret = gss_krb5_cts_crypt(cipher, &subbuf, cbcbytes, desc.iv, NULL, 0);
913 if (ret)
914 goto out_err;
915
916
917 /* Calculate our hmac over the plaintext data */
918 our_hmac_obj.len = sizeof(our_hmac);
919 our_hmac_obj.data = our_hmac;
920
921 ret = make_checksum_v2(kctx, NULL, 0, &subbuf, 0,
922 cksum_key, usage, &our_hmac_obj);
923 if (ret)
924 goto out_err;
925
926 /* Get the packet's hmac value */
927 ret = read_bytes_from_xdr_buf(buf, buf->len - kctx->gk5e->cksumlength,
928 pkt_hmac, kctx->gk5e->cksumlength);
929 if (ret)
930 goto out_err;
931
932 if (crypto_memneq(pkt_hmac, our_hmac, kctx->gk5e->cksumlength) != 0) {
933 ret = GSS_S_BAD_SIG;
934 goto out_err;
935 }
936 *headskip = kctx->gk5e->conflen;
937 *tailskip = kctx->gk5e->cksumlength;
938 out_err:
939 if (ret && ret != GSS_S_BAD_SIG)
940 ret = GSS_S_FAILURE;
941 return ret;
942 }
943
944 /*
945 * Compute Kseq given the initial session key and the checksum.
946 * Set the key of the given cipher.
947 */
948 int
krb5_rc4_setup_seq_key(struct krb5_ctx * kctx,struct crypto_skcipher * cipher,unsigned char * cksum)949 krb5_rc4_setup_seq_key(struct krb5_ctx *kctx, struct crypto_skcipher *cipher,
950 unsigned char *cksum)
951 {
952 struct crypto_shash *hmac;
953 struct shash_desc *desc;
954 u8 Kseq[GSS_KRB5_MAX_KEYLEN];
955 u32 zeroconstant = 0;
956 int err;
957
958 dprintk("%s: entered\n", __func__);
959
960 hmac = crypto_alloc_shash(kctx->gk5e->cksum_name, 0, 0);
961 if (IS_ERR(hmac)) {
962 dprintk("%s: error %ld, allocating hash '%s'\n",
963 __func__, PTR_ERR(hmac), kctx->gk5e->cksum_name);
964 return PTR_ERR(hmac);
965 }
966
967 desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(hmac),
968 GFP_NOFS);
969 if (!desc) {
970 dprintk("%s: failed to allocate shash descriptor for '%s'\n",
971 __func__, kctx->gk5e->cksum_name);
972 crypto_free_shash(hmac);
973 return -ENOMEM;
974 }
975
976 desc->tfm = hmac;
977 desc->flags = 0;
978
979 /* Compute intermediate Kseq from session key */
980 err = crypto_shash_setkey(hmac, kctx->Ksess, kctx->gk5e->keylength);
981 if (err)
982 goto out_err;
983
984 err = crypto_shash_digest(desc, (u8 *)&zeroconstant, 4, Kseq);
985 if (err)
986 goto out_err;
987
988 /* Compute final Kseq from the checksum and intermediate Kseq */
989 err = crypto_shash_setkey(hmac, Kseq, kctx->gk5e->keylength);
990 if (err)
991 goto out_err;
992
993 err = crypto_shash_digest(desc, cksum, 8, Kseq);
994 if (err)
995 goto out_err;
996
997 err = crypto_skcipher_setkey(cipher, Kseq, kctx->gk5e->keylength);
998 if (err)
999 goto out_err;
1000
1001 err = 0;
1002
1003 out_err:
1004 kzfree(desc);
1005 crypto_free_shash(hmac);
1006 dprintk("%s: returning %d\n", __func__, err);
1007 return err;
1008 }
1009
1010 /*
1011 * Compute Kcrypt given the initial session key and the plaintext seqnum.
1012 * Set the key of cipher kctx->enc.
1013 */
1014 int
krb5_rc4_setup_enc_key(struct krb5_ctx * kctx,struct crypto_skcipher * cipher,s32 seqnum)1015 krb5_rc4_setup_enc_key(struct krb5_ctx *kctx, struct crypto_skcipher *cipher,
1016 s32 seqnum)
1017 {
1018 struct crypto_shash *hmac;
1019 struct shash_desc *desc;
1020 u8 Kcrypt[GSS_KRB5_MAX_KEYLEN];
1021 u8 zeroconstant[4] = {0};
1022 u8 seqnumarray[4];
1023 int err, i;
1024
1025 dprintk("%s: entered, seqnum %u\n", __func__, seqnum);
1026
1027 hmac = crypto_alloc_shash(kctx->gk5e->cksum_name, 0, 0);
1028 if (IS_ERR(hmac)) {
1029 dprintk("%s: error %ld, allocating hash '%s'\n",
1030 __func__, PTR_ERR(hmac), kctx->gk5e->cksum_name);
1031 return PTR_ERR(hmac);
1032 }
1033
1034 desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(hmac),
1035 GFP_NOFS);
1036 if (!desc) {
1037 dprintk("%s: failed to allocate shash descriptor for '%s'\n",
1038 __func__, kctx->gk5e->cksum_name);
1039 crypto_free_shash(hmac);
1040 return -ENOMEM;
1041 }
1042
1043 desc->tfm = hmac;
1044 desc->flags = 0;
1045
1046 /* Compute intermediate Kcrypt from session key */
1047 for (i = 0; i < kctx->gk5e->keylength; i++)
1048 Kcrypt[i] = kctx->Ksess[i] ^ 0xf0;
1049
1050 err = crypto_shash_setkey(hmac, Kcrypt, kctx->gk5e->keylength);
1051 if (err)
1052 goto out_err;
1053
1054 err = crypto_shash_digest(desc, zeroconstant, 4, Kcrypt);
1055 if (err)
1056 goto out_err;
1057
1058 /* Compute final Kcrypt from the seqnum and intermediate Kcrypt */
1059 err = crypto_shash_setkey(hmac, Kcrypt, kctx->gk5e->keylength);
1060 if (err)
1061 goto out_err;
1062
1063 seqnumarray[0] = (unsigned char) ((seqnum >> 24) & 0xff);
1064 seqnumarray[1] = (unsigned char) ((seqnum >> 16) & 0xff);
1065 seqnumarray[2] = (unsigned char) ((seqnum >> 8) & 0xff);
1066 seqnumarray[3] = (unsigned char) ((seqnum >> 0) & 0xff);
1067
1068 err = crypto_shash_digest(desc, seqnumarray, 4, Kcrypt);
1069 if (err)
1070 goto out_err;
1071
1072 err = crypto_skcipher_setkey(cipher, Kcrypt, kctx->gk5e->keylength);
1073 if (err)
1074 goto out_err;
1075
1076 err = 0;
1077
1078 out_err:
1079 kzfree(desc);
1080 crypto_free_shash(hmac);
1081 dprintk("%s: returning %d\n", __func__, err);
1082 return err;
1083 }
1084
