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 
42 static inline int
43 gss_krb5_padding(int blocksize, int length)
44 {
45 	return blocksize - (length % blocksize);
46 }
47 
48 static inline void
49 gss_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 
65 static inline int
66 gss_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);
93 out:
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 
116 void
117 gss_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 		/* 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 
157 static u32
158 gss_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_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 
263 static u32
264 gss_unwrap_kerberos_v1(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf)
265 {
266 	int			signalg;
267 	int			sealalg;
268 	char			cksumdata[GSS_KRB5_MAX_CKSUM_LEN];
269 	struct xdr_netobj	md5cksum = {.len = sizeof(cksumdata),
270 					    .data = cksumdata};
271 	s32			now;
272 	int			direction;
273 	s32			seqnum;
274 	unsigned char		*ptr;
275 	int			bodysize;
276 	void			*data_start, *orig_start;
277 	int			data_len;
278 	int			blocksize;
279 	u32			conflen = kctx->gk5e->conflen;
280 	int			crypt_offset;
281 	u8			*cksumkey;
282 
283 	dprintk("RPC:       gss_unwrap_kerberos\n");
284 
285 	ptr = (u8 *)buf->head[0].iov_base + offset;
286 	if (g_verify_token_header(&kctx->mech_used, &bodysize, &ptr,
287 					buf->len - offset))
288 		return GSS_S_DEFECTIVE_TOKEN;
289 
290 	if ((ptr[0] != ((KG_TOK_WRAP_MSG >> 8) & 0xff)) ||
291 	    (ptr[1] !=  (KG_TOK_WRAP_MSG & 0xff)))
292 		return GSS_S_DEFECTIVE_TOKEN;
293 
294 	/* XXX sanity-check bodysize?? */
295 
296 	/* get the sign and seal algorithms */
297 
298 	signalg = ptr[2] + (ptr[3] << 8);
299 	if (signalg != kctx->gk5e->signalg)
300 		return GSS_S_DEFECTIVE_TOKEN;
301 
302 	sealalg = ptr[4] + (ptr[5] << 8);
303 	if (sealalg != kctx->gk5e->sealalg)
304 		return GSS_S_DEFECTIVE_TOKEN;
305 
306 	if ((ptr[6] != 0xff) || (ptr[7] != 0xff))
307 		return GSS_S_DEFECTIVE_TOKEN;
308 
309 	/*
310 	 * Data starts after token header and checksum.  ptr points
311 	 * to the beginning of the token header
312 	 */
313 	crypt_offset = ptr + (GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength) -
314 					(unsigned char *)buf->head[0].iov_base;
315 
316 	/*
317 	 * Need plaintext seqnum to derive encryption key for arcfour-hmac
318 	 */
319 	if (krb5_get_seq_num(kctx, ptr + GSS_KRB5_TOK_HDR_LEN,
320 			     ptr + 8, &direction, &seqnum))
321 		return GSS_S_BAD_SIG;
322 
323 	if ((kctx->initiate && direction != 0xff) ||
324 	    (!kctx->initiate && direction != 0))
325 		return GSS_S_BAD_SIG;
326 
327 	if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC) {
328 		struct crypto_sync_skcipher *cipher;
329 		int err;
330 
331 		cipher = crypto_alloc_sync_skcipher(kctx->gk5e->encrypt_name,
332 						    0, 0);
333 		if (IS_ERR(cipher))
334 			return GSS_S_FAILURE;
335 
336 		krb5_rc4_setup_enc_key(kctx, cipher, seqnum);
337 
338 		err = gss_decrypt_xdr_buf(cipher, buf, crypt_offset);
339 		crypto_free_sync_skcipher(cipher);
340 		if (err)
341 			return GSS_S_DEFECTIVE_TOKEN;
342 	} else {
343 		if (gss_decrypt_xdr_buf(kctx->enc, buf, crypt_offset))
344 			return GSS_S_DEFECTIVE_TOKEN;
345 	}
346 
347 	if (kctx->gk5e->keyed_cksum)
348 		cksumkey = kctx->cksum;
349 	else
350 		cksumkey = NULL;
351 
352 	if (make_checksum(kctx, ptr, 8, buf, crypt_offset,
353 					cksumkey, KG_USAGE_SEAL, &md5cksum))
354 		return GSS_S_FAILURE;
355 
356 	if (memcmp(md5cksum.data, ptr + GSS_KRB5_TOK_HDR_LEN,
357 						kctx->gk5e->cksumlength))
358 		return GSS_S_BAD_SIG;
359 
360 	/* it got through unscathed.  Make sure the context is unexpired */
361 
362 	now = get_seconds();
363 
364 	if (now > kctx->endtime)
365 		return GSS_S_CONTEXT_EXPIRED;
366 
367 	/* do sequencing checks */
368 
369 	/* Copy the data back to the right position.  XXX: Would probably be
370 	 * better to copy and encrypt at the same time. */
371 
372 	blocksize = crypto_sync_skcipher_blocksize(kctx->enc);
373 	data_start = ptr + (GSS_KRB5_TOK_HDR_LEN + kctx->gk5e->cksumlength) +
374 					conflen;
375 	orig_start = buf->head[0].iov_base + offset;
376 	data_len = (buf->head[0].iov_base + buf->head[0].iov_len) - data_start;
377 	memmove(orig_start, data_start, data_len);
378 	buf->head[0].iov_len -= (data_start - orig_start);
379 	buf->len -= (data_start - orig_start);
380 
381 	if (gss_krb5_remove_padding(buf, blocksize))
382 		return GSS_S_DEFECTIVE_TOKEN;
383 
384 	return GSS_S_COMPLETE;
385 }
386 
387 /*
388  * We can shift data by up to LOCAL_BUF_LEN bytes in a pass.  If we need
389  * to do more than that, we shift repeatedly.  Kevin Coffman reports
390  * seeing 28 bytes as the value used by Microsoft clients and servers
391  * with AES, so this constant is chosen to allow handling 28 in one pass
392  * without using too much stack space.
393  *
394  * If that proves to a problem perhaps we could use a more clever
395  * algorithm.
396  */
397 #define LOCAL_BUF_LEN 32u
398 
399 static void rotate_buf_a_little(struct xdr_buf *buf, unsigned int shift)
400 {
401 	char head[LOCAL_BUF_LEN];
402 	char tmp[LOCAL_BUF_LEN];
403 	unsigned int this_len, i;
404 
405 	BUG_ON(shift > LOCAL_BUF_LEN);
406 
407 	read_bytes_from_xdr_buf(buf, 0, head, shift);
408 	for (i = 0; i + shift < buf->len; i += LOCAL_BUF_LEN) {
409 		this_len = min(LOCAL_BUF_LEN, buf->len - (i + shift));
410 		read_bytes_from_xdr_buf(buf, i+shift, tmp, this_len);
411 		write_bytes_to_xdr_buf(buf, i, tmp, this_len);
412 	}
413 	write_bytes_to_xdr_buf(buf, buf->len - shift, head, shift);
414 }
415 
416 static void _rotate_left(struct xdr_buf *buf, unsigned int shift)
417 {
418 	int shifted = 0;
419 	int this_shift;
420 
421 	shift %= buf->len;
422 	while (shifted < shift) {
423 		this_shift = min(shift - shifted, LOCAL_BUF_LEN);
424 		rotate_buf_a_little(buf, this_shift);
425 		shifted += this_shift;
426 	}
427 }
428 
429 static void rotate_left(u32 base, struct xdr_buf *buf, unsigned int shift)
430 {
431 	struct xdr_buf subbuf;
432 
433 	xdr_buf_subsegment(buf, &subbuf, base, buf->len - base);
434 	_rotate_left(&subbuf, shift);
435 }
436 
437 static u32
438 gss_wrap_kerberos_v2(struct krb5_ctx *kctx, u32 offset,
439 		     struct xdr_buf *buf, struct page **pages)
440 {
441 	u8		*ptr, *plainhdr;
442 	s32		now;
443 	u8		flags = 0x00;
444 	__be16		*be16ptr;
445 	__be64		*be64ptr;
446 	u32		err;
447 
448 	dprintk("RPC:       %s\n", __func__);
449 
450 	if (kctx->gk5e->encrypt_v2 == NULL)
451 		return GSS_S_FAILURE;
452 
453 	/* make room for gss token header */
454 	if (xdr_extend_head(buf, offset, GSS_KRB5_TOK_HDR_LEN))
455 		return GSS_S_FAILURE;
456 
457 	/* construct gss token header */
458 	ptr = plainhdr = buf->head[0].iov_base + offset;
459 	*ptr++ = (unsigned char) ((KG2_TOK_WRAP>>8) & 0xff);
460 	*ptr++ = (unsigned char) (KG2_TOK_WRAP & 0xff);
461 
462 	if ((kctx->flags & KRB5_CTX_FLAG_INITIATOR) == 0)
463 		flags |= KG2_TOKEN_FLAG_SENTBYACCEPTOR;
464 	if ((kctx->flags & KRB5_CTX_FLAG_ACCEPTOR_SUBKEY) != 0)
465 		flags |= KG2_TOKEN_FLAG_ACCEPTORSUBKEY;
466 	/* We always do confidentiality in wrap tokens */
467 	flags |= KG2_TOKEN_FLAG_SEALED;
468 
469 	*ptr++ = flags;
470 	*ptr++ = 0xff;
471 	be16ptr = (__be16 *)ptr;
472 
473 	*be16ptr++ = 0;
474 	/* "inner" token header always uses 0 for RRC */
475 	*be16ptr++ = 0;
476 
477 	be64ptr = (__be64 *)be16ptr;
478 	*be64ptr = cpu_to_be64(atomic64_fetch_inc(&kctx->seq_send64));
479 
480 	err = (*kctx->gk5e->encrypt_v2)(kctx, offset, buf, pages);
481 	if (err)
482 		return err;
483 
484 	now = get_seconds();
485 	return (kctx->endtime < now) ? GSS_S_CONTEXT_EXPIRED : GSS_S_COMPLETE;
486 }
487 
488 static u32
489 gss_unwrap_kerberos_v2(struct krb5_ctx *kctx, int offset, struct xdr_buf *buf)
490 {
491 	s32		now;
492 	u8		*ptr;
493 	u8		flags = 0x00;
494 	u16		ec, rrc;
495 	int		err;
496 	u32		headskip, tailskip;
497 	u8		decrypted_hdr[GSS_KRB5_TOK_HDR_LEN];
498 	unsigned int	movelen;
499 
500 
501 	dprintk("RPC:       %s\n", __func__);
502 
503 	if (kctx->gk5e->decrypt_v2 == NULL)
504 		return GSS_S_FAILURE;
505 
506 	ptr = buf->head[0].iov_base + offset;
507 
508 	if (be16_to_cpu(*((__be16 *)ptr)) != KG2_TOK_WRAP)
509 		return GSS_S_DEFECTIVE_TOKEN;
510 
511 	flags = ptr[2];
512 	if ((!kctx->initiate && (flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR)) ||
513 	    (kctx->initiate && !(flags & KG2_TOKEN_FLAG_SENTBYACCEPTOR)))
514 		return GSS_S_BAD_SIG;
515 
516 	if ((flags & KG2_TOKEN_FLAG_SEALED) == 0) {
517 		dprintk("%s: token missing expected sealed flag\n", __func__);
518 		return GSS_S_DEFECTIVE_TOKEN;
519 	}
520 
521 	if (ptr[3] != 0xff)
522 		return GSS_S_DEFECTIVE_TOKEN;
523 
524 	ec = be16_to_cpup((__be16 *)(ptr + 4));
525 	rrc = be16_to_cpup((__be16 *)(ptr + 6));
526 
527 	/*
528 	 * NOTE: the sequence number at ptr + 8 is skipped, rpcsec_gss
529 	 * doesn't want it checked; see page 6 of rfc 2203.
530 	 */
531 
532 	if (rrc != 0)
533 		rotate_left(offset + 16, buf, rrc);
534 
535 	err = (*kctx->gk5e->decrypt_v2)(kctx, offset, buf,
536 					&headskip, &tailskip);
537 	if (err)
538 		return GSS_S_FAILURE;
539 
540 	/*
541 	 * Retrieve the decrypted gss token header and verify
542 	 * it against the original
543 	 */
544 	err = read_bytes_from_xdr_buf(buf,
545 				buf->len - GSS_KRB5_TOK_HDR_LEN - tailskip,
546 				decrypted_hdr, GSS_KRB5_TOK_HDR_LEN);
547 	if (err) {
548 		dprintk("%s: error %u getting decrypted_hdr\n", __func__, err);
549 		return GSS_S_FAILURE;
550 	}
551 	if (memcmp(ptr, decrypted_hdr, 6)
552 				|| memcmp(ptr + 8, decrypted_hdr + 8, 8)) {
553 		dprintk("%s: token hdr, plaintext hdr mismatch!\n", __func__);
554 		return GSS_S_FAILURE;
555 	}
556 
557 	/* do sequencing checks */
558 
559 	/* it got through unscathed.  Make sure the context is unexpired */
560 	now = get_seconds();
561 	if (now > kctx->endtime)
562 		return GSS_S_CONTEXT_EXPIRED;
563 
564 	/*
565 	 * Move the head data back to the right position in xdr_buf.
566 	 * We ignore any "ec" data since it might be in the head or
567 	 * the tail, and we really don't need to deal with it.
568 	 * Note that buf->head[0].iov_len may indicate the available
569 	 * head buffer space rather than that actually occupied.
570 	 */
571 	movelen = min_t(unsigned int, buf->head[0].iov_len, buf->len);
572 	movelen -= offset + GSS_KRB5_TOK_HDR_LEN + headskip;
573 	BUG_ON(offset + GSS_KRB5_TOK_HDR_LEN + headskip + movelen >
574 							buf->head[0].iov_len);
575 	memmove(ptr, ptr + GSS_KRB5_TOK_HDR_LEN + headskip, movelen);
576 	buf->head[0].iov_len -= GSS_KRB5_TOK_HDR_LEN + headskip;
577 	buf->len -= GSS_KRB5_TOK_HDR_LEN + headskip;
578 
579 	/* Trim off the trailing "extra count" and checksum blob */
580 	xdr_buf_trim(buf, ec + GSS_KRB5_TOK_HDR_LEN + tailskip);
581 	return GSS_S_COMPLETE;
582 }
583 
584 u32
585 gss_wrap_kerberos(struct gss_ctx *gctx, int offset,
586 		  struct xdr_buf *buf, struct page **pages)
587 {
588 	struct krb5_ctx	*kctx = gctx->internal_ctx_id;
589 
590 	switch (kctx->enctype) {
591 	default:
592 		BUG();
593 	case ENCTYPE_DES_CBC_RAW:
594 	case ENCTYPE_DES3_CBC_RAW:
595 	case ENCTYPE_ARCFOUR_HMAC:
596 		return gss_wrap_kerberos_v1(kctx, offset, buf, pages);
597 	case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
598 	case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
599 		return gss_wrap_kerberos_v2(kctx, offset, buf, pages);
600 	}
601 }
602 
603 u32
604 gss_unwrap_kerberos(struct gss_ctx *gctx, int offset, struct xdr_buf *buf)
605 {
606 	struct krb5_ctx	*kctx = gctx->internal_ctx_id;
607 
608 	switch (kctx->enctype) {
609 	default:
610 		BUG();
611 	case ENCTYPE_DES_CBC_RAW:
612 	case ENCTYPE_DES3_CBC_RAW:
613 	case ENCTYPE_ARCFOUR_HMAC:
614 		return gss_unwrap_kerberos_v1(kctx, offset, buf);
615 	case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
616 	case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
617 		return gss_unwrap_kerberos_v2(kctx, offset, buf);
618 	}
619 }
620