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1/*
2 * COPYRIGHT (c) 2008
3 * The Regents of the University of Michigan
4 * ALL RIGHTS RESERVED
5 *
6 * Permission is granted to use, copy, create derivative works
7 * and redistribute this software and such derivative works
8 * for any purpose, so long as the name of The University of
9 * Michigan is not used in any advertising or publicity
10 * pertaining to the use of distribution of this software
11 * without specific, written prior authorization. If the
12 * above copyright notice or any other identification of the
13 * University of Michigan is included in any copy of any
14 * portion of this software, then the disclaimer below must
15 * also be included.
16 *
17 * THIS SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION
18 * FROM THE UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY
19 * PURPOSE, AND WITHOUT WARRANTY BY THE UNIVERSITY OF
20 * MICHIGAN OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING
21 * WITHOUT LIMITATION THE IMPLIED WARRANTIES OF
22 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE
23 * REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE LIABLE
24 * FOR ANY DAMAGES, INCLUDING SPECIAL, INDIRECT, INCIDENTAL, OR
25 * CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM ARISING
26 * OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN
27 * IF IT HAS BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGES.
29 */
30
31#include <crypto/skcipher.h>
32#include <linux/types.h>
33#include <linux/jiffies.h>
34#include <linux/sunrpc/gss_krb5.h>
35#include <linux/random.h>
36#include <linux/pagemap.h>
37
38#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
39# define RPCDBG_FACILITY RPCDBG_AUTH
40#endif
41
42static inline int
43gss_krb5_padding(int blocksize, int length)
44{
45 return blocksize - (length % blocksize);
46}
47
48static inline void
49gss_krb5_add_padding(struct xdr_buf *buf, int offset, int blocksize)
50{
51 int padding = gss_krb5_padding(blocksize, buf->len - offset);
52 char *p;
53 struct kvec *iov;
54
55 if (buf->page_len || buf->tail[0].iov_len)
56 iov = &buf->tail[0];
57 else
58 iov = &buf->head[0];
59 p = iov->iov_base + iov->iov_len;
60 iov->iov_len += padding;
61 buf->len += padding;
62 memset(p, padding, padding);
63}
64
65static inline int
66gss_krb5_remove_padding(struct xdr_buf *buf, int blocksize)
67{
68 u8 *ptr;
69 u8 pad;
70 size_t len = buf->len;
71
72 if (len <= buf->head[0].iov_len) {
73 pad = *(u8 *)(buf->head[0].iov_base + len - 1);
74 if (pad > buf->head[0].iov_len)
75 return -EINVAL;
76 buf->head[0].iov_len -= pad;
77 goto out;
78 } else
79 len -= buf->head[0].iov_len;
80 if (len <= buf->page_len) {
81 unsigned int last = (buf->page_base + len - 1)
82 >>PAGE_SHIFT;
83 unsigned int offset = (buf->page_base + len - 1)
84 & (PAGE_SIZE - 1);
85 ptr = kmap_atomic(buf->pages[last]);
86 pad = *(ptr + offset);
87 kunmap_atomic(ptr);
88 goto out;
89 } else
90 len -= buf->page_len;
91 BUG_ON(len > buf->tail[0].iov_len);
92 pad = *(u8 *)(buf->tail[0].iov_base + len - 1);
93out:
94 /* XXX: NOTE: we do not adjust the page lengths--they represent
95 * a range of data in the real filesystem page cache, and we need
96 * to know that range so the xdr code can properly place read data.
97 * However adjusting the head length, as we do above, is harmless.
98 * In the case of a request that fits into a single page, the server
99 * also uses length and head length together to determine the original
100 * start of the request to copy the request for deferal; so it's
101 * easier on the server if we adjust head and tail length in tandem.
102 * It's not really a problem that we don't fool with the page and
103 * tail lengths, though--at worst badly formed xdr might lead the
104 * server to attempt to parse the padding.
105 * XXX: Document all these weird requirements for gss mechanism
106 * wrap/unwrap functions. */
107 if (pad > blocksize)
108 return -EINVAL;
109 if (buf->len > pad)
110 buf->len -= pad;
111 else
112 return -EINVAL;
113 return 0;
114}
115
116void
117gss_krb5_make_confounder(char *p, u32 conflen)
118{
119 static u64 i = 0;
120 u64 *q = (u64 *)p;
121
122 /* rfc1964 claims this should be "random". But all that's really
123 * necessary is that it be unique. And not even that is necessary in
124 * our case since our "gssapi" implementation exists only to support
125 * rpcsec_gss, so we know that the only buffers we will ever encrypt
126 * already begin with a unique sequence number. Just to hedge my bets
127 * I'll make a half-hearted attempt at something unique, but ensuring
128 * uniqueness would mean worrying about atomicity and rollover, and I
129 * don't care enough. */
130
131 /* initialize to random value */
132 if (i == 0) {
133 i = prandom_u32();
134 i = (i << 32) | prandom_u32();
135 }
136
137 switch (conflen) {
138 case 16:
139 *q++ = i++;
140 fallthrough;
141 case 8:
142 *q++ = i++;
143 break;
144 default:
145 BUG();
146 }
147}
148
149/* Assumptions: the head and tail of inbuf are ours to play with.
150 * The pages, however, may be real pages in the page cache and we replace
151 * them with scratch pages from **pages before writing to them. */
152/* XXX: obviously the above should be documentation of wrap interface,
153 * and shouldn't be in this kerberos-specific file. */
154
155/* XXX factor out common code with seal/unseal. */
156
157static u32
158gss_wrap_kerberos_v1(struct krb5_ctx *kctx, int offset,
159 struct xdr_buf *buf, struct page **pages)
160{
161 char cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
162 struct xdr_netobj md5cksum = {.len = sizeof(cksumdata),
163 .data = cksumdata};
164 int blocksize = 0, plainlen;
165 unsigned char *ptr, *msg_start;
166 time64_t now;
167 int headlen;
168 struct page **tmp_pages;
169 u32 seq_send;
170 u8 *cksumkey;
171 u32 conflen = kctx->gk5e->conflen;
172
173 dprintk("RPC: %s\n", __func__);
174
175 now = ktime_get_real_seconds();
176
177 blocksize = crypto_sync_skcipher_blocksize(kctx->enc);
178 gss_krb5_add_padding(buf, offset, blocksize);
179 BUG_ON((buf->len - offset) % blocksize);
180 plainlen = conflen + buf->len - offset;
181
182 headlen = g_token_size(&kctx->mech_used,
183 GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength + plainlen) -
184 (buf->len - offset);
185
186 ptr = buf->head[0].iov_base + offset;
187 /* shift data to make room for header. */
188 xdr_extend_head(buf, offset, headlen);
189
190 /* XXX Would be cleverer to encrypt while copying. */
191 BUG_ON((buf->len - offset - headlen) % blocksize);
192
193 g_make_token_header(&kctx->mech_used,
194 GSS_KRB5_TOK_HDR_LEN +
195 kctx->gk5e->cksumlength + plainlen, &ptr);
196
197
198 /* ptr now at header described in rfc 1964, section 1.2.1: */
199 ptr[0] = (unsigned char) ((KG_TOK_WRAP_MSG >> 8) & 0xff);
200 ptr[1] = (unsigned char) (KG_TOK_WRAP_MSG & 0xff);
201
202 msg_start = ptr + GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength;
203
204 /*
205 * signalg and sealalg are stored as if they were converted from LE
206 * to host endian, even though they're opaque pairs of bytes according
207 * to the RFC.
208 */
209 *(__le16 *)(ptr + 2) = cpu_to_le16(kctx->gk5e->signalg);
210 *(__le16 *)(ptr + 4) = cpu_to_le16(kctx->gk5e->sealalg);
211 ptr[6] = 0xff;
212 ptr[7] = 0xff;
213
214 gss_krb5_make_confounder(msg_start, conflen);
215
216 if (kctx->gk5e->keyed_cksum)
217 cksumkey = kctx->cksum;
218 else
219 cksumkey = NULL;
220
221 /* XXXJBF: UGH!: */
222 tmp_pages = buf->pages;
223 buf->pages = pages;
224 if (make_checksum(kctx, ptr, 8, buf, offset + headlen - conflen,
225 cksumkey, KG_USAGE_SEAL, &md5cksum))
226 return GSS_S_FAILURE;
227 buf->pages = tmp_pages;
228
229 memcpy(ptr + GSS_KRB5_TOK_HDR_LEN, md5cksum.data, md5cksum.len);
230
231 seq_send = atomic_fetch_inc(&kctx->seq_send);
232
233 /* XXX would probably be more efficient to compute checksum
234 * and encrypt at the same time: */
235 if ((krb5_make_seq_num(kctx, kctx->seq, kctx->initiate ? 0 : 0xff,
236 seq_send, ptr + GSS_KRB5_TOK_HDR_LEN, ptr + 8)))
237 return GSS_S_FAILURE;
238
239 if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC) {
240 struct crypto_sync_skcipher *cipher;
241 int err;
242 cipher = crypto_alloc_sync_skcipher(kctx->gk5e->encrypt_name,
243 0, 0);
244 if (IS_ERR(cipher))
245 return GSS_S_FAILURE;
246
247 krb5_rc4_setup_enc_key(kctx, cipher, seq_send);
248
249 err = gss_encrypt_xdr_buf(cipher, buf,
250 offset + headlen - conflen, pages);
251 crypto_free_sync_skcipher(cipher);
252 if (err)
253 return GSS_S_FAILURE;
254 } else {
255 if (gss_encrypt_xdr_buf(kctx->enc, buf,
256 offset + headlen - conflen, pages))
257 return GSS_S_FAILURE;
258 }
259
260 return (kctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;
261}
262
263static u32
264gss_unwrap_kerberos_v1(struct krb5_ctx *kctx, int offset, int len,
265 struct xdr_buf *buf, unsigned int *slack,
266 unsigned int *align)
267{
268 int signalg;
269 int sealalg;
270 char cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
271 struct xdr_netobj md5cksum = {.len = sizeof(cksumdata),
272 .data = cksumdata};
273 time64_t now;
274 int direction;
275 s32 seqnum;
276 unsigned char *ptr;
277 int bodysize;
278 void *data_start, *orig_start;
279 int data_len;
280 int blocksize;
281 u32 conflen = kctx->gk5e->conflen;
282 int crypt_offset;
283 u8 *cksumkey;
284 unsigned int saved_len = buf->len;
285
286 dprintk("RPC: gss_unwrap_kerberos\n");
287
288 ptr = (u8 *)buf->head[0].iov_base + offset;
289 if (g_verify_token_header(&kctx->mech_used, &bodysize, &ptr,
290 len - offset))
291 return GSS_S_DEFECTIVE_TOKEN;
292
293 if ((ptr[0] != ((KG_TOK_WRAP_MSG >> 8) & 0xff)) ||
294 (ptr[1] != (KG_TOK_WRAP_MSG & 0xff)))
295 return GSS_S_DEFECTIVE_TOKEN;
296
297 /* XXX sanity-check bodysize?? */
298
299 /* get the sign and seal algorithms */
300
301 signalg = ptr[2] + (ptr[3] << 8);
302 if (signalg != kctx->gk5e->signalg)
303 return GSS_S_DEFECTIVE_TOKEN;
304
305 sealalg = ptr[4] + (ptr[5] << 8);
306 if (sealalg != kctx->gk5e->sealalg)
307 return GSS_S_DEFECTIVE_TOKEN;
308
309 if ((ptr[6] != 0xff) || (ptr[7] != 0xff))
310 return GSS_S_DEFECTIVE_TOKEN;
311
312 /*
313 * Data starts after token header and checksum. ptr points
314 * to the beginning of the token header
315 */
316 crypt_offset = ptr + (GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength) -
317 (unsigned char *)buf->head[0].iov_base;
318
319 /*
320 * Need plaintext seqnum to derive encryption key for arcfour-hmac
321 */
322 if (krb5_get_seq_num(kctx, ptr + GSS_KRB5_TOK_HDR_LEN,
323 ptr + 8, &direction, &seqnum))
324 return GSS_S_BAD_SIG;
325
326 if ((kctx->initiate && direction != 0xff) ||
327 (!kctx->initiate && direction != 0))
328 return GSS_S_BAD_SIG;
329
330 buf->len = len;
331 if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC) {
332 struct crypto_sync_skcipher *cipher;
333 int err;
334
335 cipher = crypto_alloc_sync_skcipher(kctx->gk5e->encrypt_name,
336 0, 0);
337 if (IS_ERR(cipher))
338 return GSS_S_FAILURE;
339
340 krb5_rc4_setup_enc_key(kctx, cipher, seqnum);
341
342 err = gss_decrypt_xdr_buf(cipher, buf, crypt_offset);
343 crypto_free_sync_skcipher(cipher);
344 if (err)
345 return GSS_S_DEFECTIVE_TOKEN;
346 } else {
347 if (gss_decrypt_xdr_buf(kctx->enc, buf, crypt_offset))
348 return GSS_S_DEFECTIVE_TOKEN;
349 }
350
351 if (kctx->gk5e->keyed_cksum)
352 cksumkey = kctx->cksum;
353 else
354 cksumkey = NULL;
355
356 if (make_checksum(kctx, ptr, 8, buf, crypt_offset,
357 cksumkey, KG_USAGE_SEAL, &md5cksum))
358 return GSS_S_FAILURE;
359
360 if (memcmp(md5cksum.data, ptr + GSS_KRB5_TOK_HDR_LEN,
361 kctx->gk5e->cksumlength))
362 return GSS_S_BAD_SIG;
363
364 /* it got through unscathed. Make sure the context is unexpired */
365
366 now = ktime_get_real_seconds();
367
368 if (now > kctx->endtime)
369 return GSS_S_CONTEXT_EXPIRED;
370
371 /* do sequencing checks */
372
373 /* Copy the data back to the right position. XXX: Would probably be
374 * better to copy and encrypt at the same time. */
375
376 blocksize = crypto_sync_skcipher_blocksize(kctx->enc);
377 data_start = ptr + (GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength) +
378 conflen;
379 orig_start = buf->head[0].iov_base + offset;
380 data_len = (buf->head[0].iov_base + buf->head[0].iov_len) - data_start;
381 memmove(orig_start, data_start, data_len);
382 buf->head[0].iov_len -= (data_start - orig_start);
383 buf->len = len - (data_start - orig_start);
384
385 if (gss_krb5_remove_padding(buf, blocksize))
386 return GSS_S_DEFECTIVE_TOKEN;
387
388 /* slack must include room for krb5 padding */
389 *slack = XDR_QUADLEN(saved_len - buf->len);
390 /* The GSS blob always precedes the RPC message payload */
391 *align = *slack;
392 return GSS_S_COMPLETE;
393}
394
395/*
396 * We can shift data by up to LOCAL_BUF_LEN bytes in a pass. If we need
397 * to do more than that, we shift repeatedly. Kevin Coffman reports
398 * seeing 28 bytes as the value used by Microsoft clients and servers
399 * with AES, so this constant is chosen to allow handling 28 in one pass
400 * without using too much stack space.
401 *
402 * If that proves to a problem perhaps we could use a more clever
403 * algorithm.
404 */
405#define LOCAL_BUF_LEN 32u
406
407static void rotate_buf_a_little(struct xdr_buf *buf, unsigned int shift)
408{
409 char head[LOCAL_BUF_LEN];
410 char tmp[LOCAL_BUF_LEN];
411 unsigned int this_len, i;
412
413 BUG_ON(shift > LOCAL_BUF_LEN);
414
415 read_bytes_from_xdr_buf(buf, 0, head, shift);
416 for (i = 0; i + shift < buf->len; i += LOCAL_BUF_LEN) {
417 this_len = min(LOCAL_BUF_LEN, buf->len - (i + shift));
418 read_bytes_from_xdr_buf(buf, i+shift, tmp, this_len);
419 write_bytes_to_xdr_buf(buf, i, tmp, this_len);
420 }
421 write_bytes_to_xdr_buf(buf, buf->len - shift, head, shift);
422}
423
424static void _rotate_left(struct xdr_buf *buf, unsigned int shift)
425{
426 int shifted = 0;
427 int this_shift;
428
429 shift %= buf->len;
430 while (shifted < shift) {
431 this_shift = min(shift - shifted, LOCAL_BUF_LEN);
432 rotate_buf_a_little(buf, this_shift);
433 shifted += this_shift;
434 }
435}
436
437static void rotate_left(u32 base, struct xdr_buf *buf, unsigned int shift)
438{
439 struct xdr_buf subbuf;
440
441 xdr_buf_subsegment(buf, &subbuf, base, buf->len - base);
442 _rotate_left(&subbuf, shift);
443}
444
445static u32
446gss_wrap_kerberos_v2(struct krb5_ctx *kctx, u32 offset,
447 struct xdr_buf *buf, struct page **pages)
448{
449 u8 *ptr, *plainhdr;
450 time64_t now;
451 u8 flags = 0x00;
452 __be16 *be16ptr;
453 __be64 *be64ptr;
454 u32 err;
455
456 dprintk("RPC: %s\n", __func__);
457
458 if (kctx->gk5e->encrypt_v2 == NULL)
459 return GSS_S_FAILURE;
460
461 /* make room for gss token header */
462 if (xdr_extend_head(buf, offset, GSS_KRB5_TOK_HDR_LEN))
463 return GSS_S_FAILURE;
464
465 /* construct gss token header */
466 ptr = plainhdr = buf->head[0].iov_base + offset;
467 *ptr++ = (unsigned char) ((KG2_TOK_WRAP>>8) & 0xff);
468 *ptr++ = (unsigned char) (KG2_TOK_WRAP & 0xff);
469
470 if ((kctx->flags & KRB5_CTX_FLAG_INITIATOR) == 0)
471 flags |= KG2_TOKEN_FLAG_SENTBYACCEPTOR;
472 if ((kctx->flags & KRB5_CTX_FLAG_ACCEPTOR_SUBKEY) != 0)
473 flags |= KG2_TOKEN_FLAG_ACCEPTORSUBKEY;
474 /* We always do confidentiality in wrap tokens */
475 flags |= KG2_TOKEN_FLAG_SEALED;
476
477 *ptr++ = flags;
478 *ptr++ = 0xff;
479 be16ptr = (__be16 *)ptr;
480
481 *be16ptr++ = 0;
482 /* "inner" token header always uses 0 for RRC */
483 *be16ptr++ = 0;
484
485 be64ptr = (__be64 *)be16ptr;
486 *be64ptr = cpu_to_be64(atomic64_fetch_inc(&kctx->seq_send64));
487
488 err = (*kctx->gk5e->encrypt_v2)(kctx, offset, buf, pages);
489 if (err)
490 return err;
491
492 now = ktime_get_real_seconds();
493 return (kctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;
494}
495
496static u32
497gss_unwrap_kerberos_v2(struct krb5_ctx *kctx, int offset, int len,
498 struct xdr_buf *buf, unsigned int *slack,
499 unsigned int *align)
500{
501 time64_t now;
502 u8 *ptr;
503 u8 flags = 0x00;
504 u16 ec, rrc;
505 int err;
506 u32 headskip, tailskip;
507 u8 decrypted_hdr[GSS_KRB5_TOK_HDR_LEN];
508 unsigned int movelen;
509
510
511 dprintk("RPC: %s\n", __func__);
512
513 if (kctx->gk5e->decrypt_v2 == NULL)
514 return GSS_S_FAILURE;
515
516 ptr = buf->head[0].iov_base + offset;
517
518 if (be16_to_cpu(*((__be16 *)ptr)) != KG2_TOK_WRAP)
519 return GSS_S_DEFECTIVE_TOKEN;
520
521 flags = ptr[2];
522 if ((!kctx->initiate && (flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR)) ||
523 (kctx->initiate && !(flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR)))
524 return GSS_S_BAD_SIG;
525
526 if ((flags & KG2_TOKEN_FLAG_SEALED) == 0) {
527 dprintk("%s: token missing expected sealed flag\n", __func__);
528 return GSS_S_DEFECTIVE_TOKEN;
529 }
530
531 if (ptr[3] != 0xff)
532 return GSS_S_DEFECTIVE_TOKEN;
533
534 ec = be16_to_cpup((__be16 *)(ptr + 4));
535 rrc = be16_to_cpup((__be16 *)(ptr + 6));
536
537 /*
538 * NOTE: the sequence number at ptr + 8 is skipped, rpcsec_gss
539 * doesn't want it checked; see page 6 of rfc 2203.
540 */
541
542 if (rrc != 0)
543 rotate_left(offset + 16, buf, rrc);
544
545 err = (*kctx->gk5e->decrypt_v2)(kctx, offset, len, buf,
546 &headskip, &tailskip);
547 if (err)
548 return GSS_S_FAILURE;
549
550 /*
551 * Retrieve the decrypted gss token header and verify
552 * it against the original
553 */
554 err = read_bytes_from_xdr_buf(buf,
555 len - GSS_KRB5_TOK_HDR_LEN - tailskip,
556 decrypted_hdr, GSS_KRB5_TOK_HDR_LEN);
557 if (err) {
558 dprintk("%s: error %u getting decrypted_hdr\n", __func__, err);
559 return GSS_S_FAILURE;
560 }
561 if (memcmp(ptr, decrypted_hdr, 6)
562 || memcmp(ptr + 8, decrypted_hdr + 8, 8)) {
563 dprintk("%s: token hdr, plaintext hdr mismatch!\n", __func__);
564 return GSS_S_FAILURE;
565 }
566
567 /* do sequencing checks */
568
569 /* it got through unscathed. Make sure the context is unexpired */
570 now = ktime_get_real_seconds();
571 if (now > kctx->endtime)
572 return GSS_S_CONTEXT_EXPIRED;
573
574 /*
575 * Move the head data back to the right position in xdr_buf.
576 * We ignore any "ec" data since it might be in the head or
577 * the tail, and we really don't need to deal with it.
578 * Note that buf->head[0].iov_len may indicate the available
579 * head buffer space rather than that actually occupied.
580 */
581 movelen = min_t(unsigned int, buf->head[0].iov_len, len);
582 movelen -= offset + GSS_KRB5_TOK_HDR_LEN + headskip;
583 BUG_ON(offset + GSS_KRB5_TOK_HDR_LEN + headskip + movelen >
584 buf->head[0].iov_len);
585 memmove(ptr, ptr + GSS_KRB5_TOK_HDR_LEN + headskip, movelen);
586 buf->head[0].iov_len -= GSS_KRB5_TOK_HDR_LEN + headskip;
587 buf->len = len - (GSS_KRB5_TOK_HDR_LEN + headskip);
588
589 /* Trim off the trailing "extra count" and checksum blob */
590 xdr_buf_trim(buf, ec + GSS_KRB5_TOK_HDR_LEN + tailskip);
591
592 *align = XDR_QUADLEN(GSS_KRB5_TOK_HDR_LEN + headskip);
593 *slack = *align + XDR_QUADLEN(ec + GSS_KRB5_TOK_HDR_LEN + tailskip);
594 return GSS_S_COMPLETE;
595}
596
597u32
598gss_wrap_kerberos(struct gss_ctx *gctx, int offset,
599 struct xdr_buf *buf, struct page **pages)
600{
601 struct krb5_ctx *kctx = gctx->internal_ctx_id;
602
603 switch (kctx->enctype) {
604 default:
605 BUG();
606 case ENCTYPE_DES_CBC_RAW:
607 case ENCTYPE_DES3_CBC_RAW:
608 case ENCTYPE_ARCFOUR_HMAC:
609 return gss_wrap_kerberos_v1(kctx, offset, buf, pages);
610 case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
611 case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
612 return gss_wrap_kerberos_v2(kctx, offset, buf, pages);
613 }
614}
615
616u32
617gss_unwrap_kerberos(struct gss_ctx *gctx, int offset,
618 int len, struct xdr_buf *buf)
619{
620 struct krb5_ctx *kctx = gctx->internal_ctx_id;
621
622 switch (kctx->enctype) {
623 default:
624 BUG();
625 case ENCTYPE_DES_CBC_RAW:
626 case ENCTYPE_DES3_CBC_RAW:
627 case ENCTYPE_ARCFOUR_HMAC:
628 return gss_unwrap_kerberos_v1(kctx, offset, len, buf,
629 &gctx->slack, &gctx->align);
630 case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
631 case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
632 return gss_unwrap_kerberos_v2(kctx, offset, len, buf,
633 &gctx->slack, &gctx->align);
634 }
635}
1/*
2 * COPYRIGHT (c) 2008
3 * The Regents of the University of Michigan
4 * ALL RIGHTS RESERVED
5 *
6 * Permission is granted to use, copy, create derivative works
7 * and redistribute this software and such derivative works
8 * for any purpose, so long as the name of The University of
9 * Michigan is not used in any advertising or publicity
10 * pertaining to the use of distribution of this software
11 * without specific, written prior authorization. If the
12 * above copyright notice or any other identification of the
13 * University of Michigan is included in any copy of any
14 * portion of this software, then the disclaimer below must
15 * also be included.
16 *
17 * THIS SOFTWARE IS PROVIDED AS IS, WITHOUT REPRESENTATION
18 * FROM THE UNIVERSITY OF MICHIGAN AS TO ITS FITNESS FOR ANY
19 * PURPOSE, AND WITHOUT WARRANTY BY THE UNIVERSITY OF
20 * MICHIGAN OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING
21 * WITHOUT LIMITATION THE IMPLIED WARRANTIES OF
22 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE
23 * REGENTS OF THE UNIVERSITY OF MICHIGAN SHALL NOT BE LIABLE
24 * FOR ANY DAMAGES, INCLUDING SPECIAL, INDIRECT, INCIDENTAL, OR
25 * CONSEQUENTIAL DAMAGES, WITH RESPECT TO ANY CLAIM ARISING
26 * OUT OF OR IN CONNECTION WITH THE USE OF THE SOFTWARE, EVEN
27 * IF IT HAS BEEN OR IS HEREAFTER ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGES.
29 */
30
31#include <linux/types.h>
32#include <linux/jiffies.h>
33#include <linux/sunrpc/gss_krb5.h>
34#include <linux/random.h>
35#include <linux/pagemap.h>
36#include <linux/crypto.h>
37
38#ifdef RPC_DEBUG
39# define RPCDBG_FACILITY RPCDBG_AUTH
40#endif
41
42static inline int
43gss_krb5_padding(int blocksize, int length)
44{
45 return blocksize - (length % blocksize);
46}
47
48static inline void
49gss_krb5_add_padding(struct xdr_buf *buf, int offset, int blocksize)
50{
51 int padding = gss_krb5_padding(blocksize, buf->len - offset);
52 char *p;
53 struct kvec *iov;
54
55 if (buf->page_len || buf->tail[0].iov_len)
56 iov = &buf->tail[0];
57 else
58 iov = &buf->head[0];
59 p = iov->iov_base + iov->iov_len;
60 iov->iov_len += padding;
61 buf->len += padding;
62 memset(p, padding, padding);
63}
64
65static inline int
66gss_krb5_remove_padding(struct xdr_buf *buf, int blocksize)
67{
68 u8 *ptr;
69 u8 pad;
70 size_t len = buf->len;
71
72 if (len <= buf->head[0].iov_len) {
73 pad = *(u8 *)(buf->head[0].iov_base + len - 1);
74 if (pad > buf->head[0].iov_len)
75 return -EINVAL;
76 buf->head[0].iov_len -= pad;
77 goto out;
78 } else
79 len -= buf->head[0].iov_len;
80 if (len <= buf->page_len) {
81 unsigned int last = (buf->page_base + len - 1)
82 >>PAGE_CACHE_SHIFT;
83 unsigned int offset = (buf->page_base + len - 1)
84 & (PAGE_CACHE_SIZE - 1);
85 ptr = kmap_atomic(buf->pages[last], KM_USER0);
86 pad = *(ptr + offset);
87 kunmap_atomic(ptr, KM_USER0);
88 goto out;
89 } else
90 len -= buf->page_len;
91 BUG_ON(len > buf->tail[0].iov_len);
92 pad = *(u8 *)(buf->tail[0].iov_base + len - 1);
93out:
94 /* XXX: NOTE: we do not adjust the page lengths--they represent
95 * a range of data in the real filesystem page cache, and we need
96 * to know that range so the xdr code can properly place read data.
97 * However adjusting the head length, as we do above, is harmless.
98 * In the case of a request that fits into a single page, the server
99 * also uses length and head length together to determine the original
100 * start of the request to copy the request for deferal; so it's
101 * easier on the server if we adjust head and tail length in tandem.
102 * It's not really a problem that we don't fool with the page and
103 * tail lengths, though--at worst badly formed xdr might lead the
104 * server to attempt to parse the padding.
105 * XXX: Document all these weird requirements for gss mechanism
106 * wrap/unwrap functions. */
107 if (pad > blocksize)
108 return -EINVAL;
109 if (buf->len > pad)
110 buf->len -= pad;
111 else
112 return -EINVAL;
113 return 0;
114}
115
116void
117gss_krb5_make_confounder(char *p, u32 conflen)
118{
119 static u64 i = 0;
120 u64 *q = (u64 *)p;
121
122 /* rfc1964 claims this should be "random". But all that's really
123 * necessary is that it be unique. And not even that is necessary in
124 * our case since our "gssapi" implementation exists only to support
125 * rpcsec_gss, so we know that the only buffers we will ever encrypt
126 * already begin with a unique sequence number. Just to hedge my bets
127 * I'll make a half-hearted attempt at something unique, but ensuring
128 * uniqueness would mean worrying about atomicity and rollover, and I
129 * don't care enough. */
130
131 /* initialize to random value */
132 if (i == 0) {
133 i = random32();
134 i = (i << 32) | random32();
135 }
136
137 switch (conflen) {
138 case 16:
139 *q++ = i++;
140 /* fall through */
141 case 8:
142 *q++ = i++;
143 break;
144 default:
145 BUG();
146 }
147}
148
149/* Assumptions: the head and tail of inbuf are ours to play with.
150 * The pages, however, may be real pages in the page cache and we replace
151 * them with scratch pages from **pages before writing to them. */
152/* XXX: obviously the above should be documentation of wrap interface,
153 * and shouldn't be in this kerberos-specific file. */
154
155/* XXX factor out common code with seal/unseal. */
156
157static u32
158gss_wrap_kerberos_v1(struct krb5_ctx *kctx, int offset,
159 struct xdr_buf *buf, struct page **pages)
160{
161 char cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
162 struct xdr_netobj md5cksum = {.len = sizeof(cksumdata),
163 .data = cksumdata};
164 int blocksize = 0, plainlen;
165 unsigned char *ptr, *msg_start;
166 s32 now;
167 int headlen;
168 struct page **tmp_pages;
169 u32 seq_send;
170 u8 *cksumkey;
171 u32 conflen = kctx->gk5e->conflen;
172
173 dprintk("RPC: %s\n", __func__);
174
175 now = get_seconds();
176
177 blocksize = crypto_blkcipher_blocksize(kctx->enc);
178 gss_krb5_add_padding(buf, offset, blocksize);
179 BUG_ON((buf->len - offset) % blocksize);
180 plainlen = conflen + buf->len - offset;
181
182 headlen = g_token_size(&kctx->mech_used,
183 GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength + plainlen) -
184 (buf->len - offset);
185
186 ptr = buf->head[0].iov_base + offset;
187 /* shift data to make room for header. */
188 xdr_extend_head(buf, offset, headlen);
189
190 /* XXX Would be cleverer to encrypt while copying. */
191 BUG_ON((buf->len - offset - headlen) % blocksize);
192
193 g_make_token_header(&kctx->mech_used,
194 GSS_KRB5_TOK_HDR_LEN +
195 kctx->gk5e->cksumlength + plainlen, &ptr);
196
197
198 /* ptr now at header described in rfc 1964, section 1.2.1: */
199 ptr[0] = (unsigned char) ((KG_TOK_WRAP_MSG >> 8) & 0xff);
200 ptr[1] = (unsigned char) (KG_TOK_WRAP_MSG & 0xff);
201
202 msg_start = ptr + GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength;
203
204 *(__be16 *)(ptr + 2) = cpu_to_le16(kctx->gk5e->signalg);
205 memset(ptr + 4, 0xff, 4);
206 *(__be16 *)(ptr + 4) = cpu_to_le16(kctx->gk5e->sealalg);
207
208 gss_krb5_make_confounder(msg_start, conflen);
209
210 if (kctx->gk5e->keyed_cksum)
211 cksumkey = kctx->cksum;
212 else
213 cksumkey = NULL;
214
215 /* XXXJBF: UGH!: */
216 tmp_pages = buf->pages;
217 buf->pages = pages;
218 if (make_checksum(kctx, ptr, 8, buf, offset + headlen - conflen,
219 cksumkey, KG_USAGE_SEAL, &md5cksum))
220 return GSS_S_FAILURE;
221 buf->pages = tmp_pages;
222
223 memcpy(ptr + GSS_KRB5_TOK_HDR_LEN, md5cksum.data, md5cksum.len);
224
225 spin_lock(&krb5_seq_lock);
226 seq_send = kctx->seq_send++;
227 spin_unlock(&krb5_seq_lock);
228
229 /* XXX would probably be more efficient to compute checksum
230 * and encrypt at the same time: */
231 if ((krb5_make_seq_num(kctx, kctx->seq, kctx->initiate ? 0 : 0xff,
232 seq_send, ptr + GSS_KRB5_TOK_HDR_LEN, ptr + 8)))
233 return GSS_S_FAILURE;
234
235 if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC) {
236 struct crypto_blkcipher *cipher;
237 int err;
238 cipher = crypto_alloc_blkcipher(kctx->gk5e->encrypt_name, 0,
239 CRYPTO_ALG_ASYNC);
240 if (IS_ERR(cipher))
241 return GSS_S_FAILURE;
242
243 krb5_rc4_setup_enc_key(kctx, cipher, seq_send);
244
245 err = gss_encrypt_xdr_buf(cipher, buf,
246 offset + headlen - conflen, pages);
247 crypto_free_blkcipher(cipher);
248 if (err)
249 return GSS_S_FAILURE;
250 } else {
251 if (gss_encrypt_xdr_buf(kctx->enc, buf,
252 offset + headlen - conflen, pages))
253 return GSS_S_FAILURE;
254 }
255
256 return (kctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;
257}
258
259static u32
260gss_unwrap_kerberos_v1(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf)
261{
262 int signalg;
263 int sealalg;
264 char cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
265 struct xdr_netobj md5cksum = {.len = sizeof(cksumdata),
266 .data = cksumdata};
267 s32 now;
268 int direction;
269 s32 seqnum;
270 unsigned char *ptr;
271 int bodysize;
272 void *data_start, *orig_start;
273 int data_len;
274 int blocksize;
275 u32 conflen = kctx->gk5e->conflen;
276 int crypt_offset;
277 u8 *cksumkey;
278
279 dprintk("RPC: gss_unwrap_kerberos\n");
280
281 ptr = (u8 *)buf->head[0].iov_base + offset;
282 if (g_verify_token_header(&kctx->mech_used, &bodysize, &ptr,
283 buf->len - offset))
284 return GSS_S_DEFECTIVE_TOKEN;
285
286 if ((ptr[0] != ((KG_TOK_WRAP_MSG >> 8) & 0xff)) ||
287 (ptr[1] != (KG_TOK_WRAP_MSG & 0xff)))
288 return GSS_S_DEFECTIVE_TOKEN;
289
290 /* XXX sanity-check bodysize?? */
291
292 /* get the sign and seal algorithms */
293
294 signalg = ptr[2] + (ptr[3] << 8);
295 if (signalg != kctx->gk5e->signalg)
296 return GSS_S_DEFECTIVE_TOKEN;
297
298 sealalg = ptr[4] + (ptr[5] << 8);
299 if (sealalg != kctx->gk5e->sealalg)
300 return GSS_S_DEFECTIVE_TOKEN;
301
302 if ((ptr[6] != 0xff) || (ptr[7] != 0xff))
303 return GSS_S_DEFECTIVE_TOKEN;
304
305 /*
306 * Data starts after token header and checksum. ptr points
307 * to the beginning of the token header
308 */
309 crypt_offset = ptr + (GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength) -
310 (unsigned char *)buf->head[0].iov_base;
311
312 /*
313 * Need plaintext seqnum to derive encryption key for arcfour-hmac
314 */
315 if (krb5_get_seq_num(kctx, ptr + GSS_KRB5_TOK_HDR_LEN,
316 ptr + 8, &direction, &seqnum))
317 return GSS_S_BAD_SIG;
318
319 if ((kctx->initiate && direction != 0xff) ||
320 (!kctx->initiate && direction != 0))
321 return GSS_S_BAD_SIG;
322
323 if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC) {
324 struct crypto_blkcipher *cipher;
325 int err;
326
327 cipher = crypto_alloc_blkcipher(kctx->gk5e->encrypt_name, 0,
328 CRYPTO_ALG_ASYNC);
329 if (IS_ERR(cipher))
330 return GSS_S_FAILURE;
331
332 krb5_rc4_setup_enc_key(kctx, cipher, seqnum);
333
334 err = gss_decrypt_xdr_buf(cipher, buf, crypt_offset);
335 crypto_free_blkcipher(cipher);
336 if (err)
337 return GSS_S_DEFECTIVE_TOKEN;
338 } else {
339 if (gss_decrypt_xdr_buf(kctx->enc, buf, crypt_offset))
340 return GSS_S_DEFECTIVE_TOKEN;
341 }
342
343 if (kctx->gk5e->keyed_cksum)
344 cksumkey = kctx->cksum;
345 else
346 cksumkey = NULL;
347
348 if (make_checksum(kctx, ptr, 8, buf, crypt_offset,
349 cksumkey, KG_USAGE_SEAL, &md5cksum))
350 return GSS_S_FAILURE;
351
352 if (memcmp(md5cksum.data, ptr + GSS_KRB5_TOK_HDR_LEN,
353 kctx->gk5e->cksumlength))
354 return GSS_S_BAD_SIG;
355
356 /* it got through unscathed. Make sure the context is unexpired */
357
358 now = get_seconds();
359
360 if (now > kctx->endtime)
361 return GSS_S_CONTEXT_EXPIRED;
362
363 /* do sequencing checks */
364
365 /* Copy the data back to the right position. XXX: Would probably be
366 * better to copy and encrypt at the same time. */
367
368 blocksize = crypto_blkcipher_blocksize(kctx->enc);
369 data_start = ptr + (GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength) +
370 conflen;
371 orig_start = buf->head[0].iov_base + offset;
372 data_len = (buf->head[0].iov_base + buf->head[0].iov_len) - data_start;
373 memmove(orig_start, data_start, data_len);
374 buf->head[0].iov_len -= (data_start - orig_start);
375 buf->len -= (data_start - orig_start);
376
377 if (gss_krb5_remove_padding(buf, blocksize))
378 return GSS_S_DEFECTIVE_TOKEN;
379
380 return GSS_S_COMPLETE;
381}
382
383/*
384 * We cannot currently handle tokens with rotated data. We need a
385 * generalized routine to rotate the data in place. It is anticipated
386 * that we won't encounter rotated data in the general case.
387 */
388static u32
389rotate_left(struct krb5_ctx *kctx, u32 offset, struct xdr_buf *buf, u16 rrc)
390{
391 unsigned int realrrc = rrc % (buf->len - offset - GSS_KRB5_TOK_HDR_LEN);
392
393 if (realrrc == 0)
394 return 0;
395
396 dprintk("%s: cannot process token with rotated data: "
397 "rrc %u, realrrc %u\n", __func__, rrc, realrrc);
398 return 1;
399}
400
401static u32
402gss_wrap_kerberos_v2(struct krb5_ctx *kctx, u32 offset,
403 struct xdr_buf *buf, struct page **pages)
404{
405 int blocksize;
406 u8 *ptr, *plainhdr;
407 s32 now;
408 u8 flags = 0x00;
409 __be16 *be16ptr, ec = 0;
410 __be64 *be64ptr;
411 u32 err;
412
413 dprintk("RPC: %s\n", __func__);
414
415 if (kctx->gk5e->encrypt_v2 == NULL)
416 return GSS_S_FAILURE;
417
418 /* make room for gss token header */
419 if (xdr_extend_head(buf, offset, GSS_KRB5_TOK_HDR_LEN))
420 return GSS_S_FAILURE;
421
422 /* construct gss token header */
423 ptr = plainhdr = buf->head[0].iov_base + offset;
424 *ptr++ = (unsigned char) ((KG2_TOK_WRAP>>8) & 0xff);
425 *ptr++ = (unsigned char) (KG2_TOK_WRAP & 0xff);
426
427 if ((kctx->flags & KRB5_CTX_FLAG_INITIATOR) == 0)
428 flags |= KG2_TOKEN_FLAG_SENTBYACCEPTOR;
429 if ((kctx->flags & KRB5_CTX_FLAG_ACCEPTOR_SUBKEY) != 0)
430 flags |= KG2_TOKEN_FLAG_ACCEPTORSUBKEY;
431 /* We always do confidentiality in wrap tokens */
432 flags |= KG2_TOKEN_FLAG_SEALED;
433
434 *ptr++ = flags;
435 *ptr++ = 0xff;
436 be16ptr = (__be16 *)ptr;
437
438 blocksize = crypto_blkcipher_blocksize(kctx->acceptor_enc);
439 *be16ptr++ = cpu_to_be16(ec);
440 /* "inner" token header always uses 0 for RRC */
441 *be16ptr++ = cpu_to_be16(0);
442
443 be64ptr = (__be64 *)be16ptr;
444 spin_lock(&krb5_seq_lock);
445 *be64ptr = cpu_to_be64(kctx->seq_send64++);
446 spin_unlock(&krb5_seq_lock);
447
448 err = (*kctx->gk5e->encrypt_v2)(kctx, offset, buf, ec, pages);
449 if (err)
450 return err;
451
452 now = get_seconds();
453 return (kctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;
454}
455
456static u32
457gss_unwrap_kerberos_v2(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf)
458{
459 s32 now;
460 u64 seqnum;
461 u8 *ptr;
462 u8 flags = 0x00;
463 u16 ec, rrc;
464 int err;
465 u32 headskip, tailskip;
466 u8 decrypted_hdr[GSS_KRB5_TOK_HDR_LEN];
467 unsigned int movelen;
468
469
470 dprintk("RPC: %s\n", __func__);
471
472 if (kctx->gk5e->decrypt_v2 == NULL)
473 return GSS_S_FAILURE;
474
475 ptr = buf->head[0].iov_base + offset;
476
477 if (be16_to_cpu(*((__be16 *)ptr)) != KG2_TOK_WRAP)
478 return GSS_S_DEFECTIVE_TOKEN;
479
480 flags = ptr[2];
481 if ((!kctx->initiate && (flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR)) ||
482 (kctx->initiate && !(flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR)))
483 return GSS_S_BAD_SIG;
484
485 if ((flags & KG2_TOKEN_FLAG_SEALED) == 0) {
486 dprintk("%s: token missing expected sealed flag\n", __func__);
487 return GSS_S_DEFECTIVE_TOKEN;
488 }
489
490 if (ptr[3] != 0xff)
491 return GSS_S_DEFECTIVE_TOKEN;
492
493 ec = be16_to_cpup((__be16 *)(ptr + 4));
494 rrc = be16_to_cpup((__be16 *)(ptr + 6));
495
496 seqnum = be64_to_cpup((__be64 *)(ptr + 8));
497
498 if (rrc != 0) {
499 err = rotate_left(kctx, offset, buf, rrc);
500 if (err)
501 return GSS_S_FAILURE;
502 }
503
504 err = (*kctx->gk5e->decrypt_v2)(kctx, offset, buf,
505 &headskip, &tailskip);
506 if (err)
507 return GSS_S_FAILURE;
508
509 /*
510 * Retrieve the decrypted gss token header and verify
511 * it against the original
512 */
513 err = read_bytes_from_xdr_buf(buf,
514 buf->len - GSS_KRB5_TOK_HDR_LEN - tailskip,
515 decrypted_hdr, GSS_KRB5_TOK_HDR_LEN);
516 if (err) {
517 dprintk("%s: error %u getting decrypted_hdr\n", __func__, err);
518 return GSS_S_FAILURE;
519 }
520 if (memcmp(ptr, decrypted_hdr, 6)
521 || memcmp(ptr + 8, decrypted_hdr + 8, 8)) {
522 dprintk("%s: token hdr, plaintext hdr mismatch!\n", __func__);
523 return GSS_S_FAILURE;
524 }
525
526 /* do sequencing checks */
527
528 /* it got through unscathed. Make sure the context is unexpired */
529 now = get_seconds();
530 if (now > kctx->endtime)
531 return GSS_S_CONTEXT_EXPIRED;
532
533 /*
534 * Move the head data back to the right position in xdr_buf.
535 * We ignore any "ec" data since it might be in the head or
536 * the tail, and we really don't need to deal with it.
537 * Note that buf->head[0].iov_len may indicate the available
538 * head buffer space rather than that actually occupied.
539 */
540 movelen = min_t(unsigned int, buf->head[0].iov_len, buf->len);
541 movelen -= offset + GSS_KRB5_TOK_HDR_LEN + headskip;
542 BUG_ON(offset + GSS_KRB5_TOK_HDR_LEN + headskip + movelen >
543 buf->head[0].iov_len);
544 memmove(ptr, ptr + GSS_KRB5_TOK_HDR_LEN + headskip, movelen);
545 buf->head[0].iov_len -= GSS_KRB5_TOK_HDR_LEN + headskip;
546 buf->len -= GSS_KRB5_TOK_HDR_LEN + headskip;
547
548 return GSS_S_COMPLETE;
549}
550
551u32
552gss_wrap_kerberos(struct gss_ctx *gctx, int offset,
553 struct xdr_buf *buf, struct page **pages)
554{
555 struct krb5_ctx *kctx = gctx->internal_ctx_id;
556
557 switch (kctx->enctype) {
558 default:
559 BUG();
560 case ENCTYPE_DES_CBC_RAW:
561 case ENCTYPE_DES3_CBC_RAW:
562 case ENCTYPE_ARCFOUR_HMAC:
563 return gss_wrap_kerberos_v1(kctx, offset, buf, pages);
564 case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
565 case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
566 return gss_wrap_kerberos_v2(kctx, offset, buf, pages);
567 }
568}
569
570u32
571gss_unwrap_kerberos(struct gss_ctx *gctx, int offset, struct xdr_buf *buf)
572{
573 struct krb5_ctx *kctx = gctx->internal_ctx_id;
574
575 switch (kctx->enctype) {
576 default:
577 BUG();
578 case ENCTYPE_DES_CBC_RAW:
579 case ENCTYPE_DES3_CBC_RAW:
580 case ENCTYPE_ARCFOUR_HMAC:
581 return gss_unwrap_kerberos_v1(kctx, offset, buf);
582 case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
583 case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
584 return gss_unwrap_kerberos_v2(kctx, offset, buf);
585 }
586}
587