1 /*
2  *  linux/net/sunrpc/gss_krb5_mech.c
3  *
4  *  Copyright (c) 2001-2008 The Regents of the University of Michigan.
5  *  All rights reserved.
6  *
7  *  Andy Adamson <andros@umich.edu>
8  *  J. Bruce Fields <bfields@umich.edu>
9  *
10  *  Redistribution and use in source and binary forms, with or without
11  *  modification, are permitted provided that the following conditions
12  *  are met:
13  *
14  *  1. Redistributions of source code must retain the above copyright
15  *     notice, this list of conditions and the following disclaimer.
16  *  2. Redistributions in binary form must reproduce the above copyright
17  *     notice, this list of conditions and the following disclaimer in the
18  *     documentation and/or other materials provided with the distribution.
19  *  3. Neither the name of the University nor the names of its
20  *     contributors may be used to endorse or promote products derived
21  *     from this software without specific prior written permission.
22  *
23  *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
24  *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
25  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
26  *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27  *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
28  *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
29  *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
30  *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
31  *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
32  *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
33  *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34  *
35  */
36 
37 #include <linux/err.h>
38 #include <linux/module.h>
39 #include <linux/init.h>
40 #include <linux/types.h>
41 #include <linux/slab.h>
42 #include <linux/sunrpc/auth.h>
43 #include <linux/sunrpc/gss_krb5.h>
44 #include <linux/sunrpc/xdr.h>
45 #include <linux/crypto.h>
46 #include <linux/sunrpc/gss_krb5_enctypes.h>
47 
48 #ifdef RPC_DEBUG
49 # define RPCDBG_FACILITY	RPCDBG_AUTH
50 #endif
51 
52 static struct gss_api_mech gss_kerberos_mech;	/* forward declaration */
53 
54 static const struct gss_krb5_enctype supported_gss_krb5_enctypes[] = {
55 	/*
56 	 * DES (All DES enctypes are mapped to the same gss functionality)
57 	 */
58 	{
59 	  .etype = ENCTYPE_DES_CBC_RAW,
60 	  .ctype = CKSUMTYPE_RSA_MD5,
61 	  .name = "des-cbc-crc",
62 	  .encrypt_name = "cbc(des)",
63 	  .cksum_name = "md5",
64 	  .encrypt = krb5_encrypt,
65 	  .decrypt = krb5_decrypt,
66 	  .mk_key = NULL,
67 	  .signalg = SGN_ALG_DES_MAC_MD5,
68 	  .sealalg = SEAL_ALG_DES,
69 	  .keybytes = 7,
70 	  .keylength = 8,
71 	  .blocksize = 8,
72 	  .conflen = 8,
73 	  .cksumlength = 8,
74 	  .keyed_cksum = 0,
75 	},
76 	/*
77 	 * RC4-HMAC
78 	 */
79 	{
80 	  .etype = ENCTYPE_ARCFOUR_HMAC,
81 	  .ctype = CKSUMTYPE_HMAC_MD5_ARCFOUR,
82 	  .name = "rc4-hmac",
83 	  .encrypt_name = "ecb(arc4)",
84 	  .cksum_name = "hmac(md5)",
85 	  .encrypt = krb5_encrypt,
86 	  .decrypt = krb5_decrypt,
87 	  .mk_key = NULL,
88 	  .signalg = SGN_ALG_HMAC_MD5,
89 	  .sealalg = SEAL_ALG_MICROSOFT_RC4,
90 	  .keybytes = 16,
91 	  .keylength = 16,
92 	  .blocksize = 1,
93 	  .conflen = 8,
94 	  .cksumlength = 8,
95 	  .keyed_cksum = 1,
96 	},
97 	/*
98 	 * 3DES
99 	 */
100 	{
101 	  .etype = ENCTYPE_DES3_CBC_RAW,
102 	  .ctype = CKSUMTYPE_HMAC_SHA1_DES3,
103 	  .name = "des3-hmac-sha1",
104 	  .encrypt_name = "cbc(des3_ede)",
105 	  .cksum_name = "hmac(sha1)",
106 	  .encrypt = krb5_encrypt,
107 	  .decrypt = krb5_decrypt,
108 	  .mk_key = gss_krb5_des3_make_key,
109 	  .signalg = SGN_ALG_HMAC_SHA1_DES3_KD,
110 	  .sealalg = SEAL_ALG_DES3KD,
111 	  .keybytes = 21,
112 	  .keylength = 24,
113 	  .blocksize = 8,
114 	  .conflen = 8,
115 	  .cksumlength = 20,
116 	  .keyed_cksum = 1,
117 	},
118 	/*
119 	 * AES128
120 	 */
121 	{
122 	  .etype = ENCTYPE_AES128_CTS_HMAC_SHA1_96,
123 	  .ctype = CKSUMTYPE_HMAC_SHA1_96_AES128,
124 	  .name = "aes128-cts",
125 	  .encrypt_name = "cts(cbc(aes))",
126 	  .cksum_name = "hmac(sha1)",
127 	  .encrypt = krb5_encrypt,
128 	  .decrypt = krb5_decrypt,
129 	  .mk_key = gss_krb5_aes_make_key,
130 	  .encrypt_v2 = gss_krb5_aes_encrypt,
131 	  .decrypt_v2 = gss_krb5_aes_decrypt,
132 	  .signalg = -1,
133 	  .sealalg = -1,
134 	  .keybytes = 16,
135 	  .keylength = 16,
136 	  .blocksize = 16,
137 	  .conflen = 16,
138 	  .cksumlength = 12,
139 	  .keyed_cksum = 1,
140 	},
141 	/*
142 	 * AES256
143 	 */
144 	{
145 	  .etype = ENCTYPE_AES256_CTS_HMAC_SHA1_96,
146 	  .ctype = CKSUMTYPE_HMAC_SHA1_96_AES256,
147 	  .name = "aes256-cts",
148 	  .encrypt_name = "cts(cbc(aes))",
149 	  .cksum_name = "hmac(sha1)",
150 	  .encrypt = krb5_encrypt,
151 	  .decrypt = krb5_decrypt,
152 	  .mk_key = gss_krb5_aes_make_key,
153 	  .encrypt_v2 = gss_krb5_aes_encrypt,
154 	  .decrypt_v2 = gss_krb5_aes_decrypt,
155 	  .signalg = -1,
156 	  .sealalg = -1,
157 	  .keybytes = 32,
158 	  .keylength = 32,
159 	  .blocksize = 16,
160 	  .conflen = 16,
161 	  .cksumlength = 12,
162 	  .keyed_cksum = 1,
163 	},
164 };
165 
166 static const int num_supported_enctypes =
167 	ARRAY_SIZE(supported_gss_krb5_enctypes);
168 
169 static int
170 supported_gss_krb5_enctype(int etype)
171 {
172 	int i;
173 	for (i = 0; i < num_supported_enctypes; i++)
174 		if (supported_gss_krb5_enctypes[i].etype == etype)
175 			return 1;
176 	return 0;
177 }
178 
179 static const struct gss_krb5_enctype *
180 get_gss_krb5_enctype(int etype)
181 {
182 	int i;
183 	for (i = 0; i < num_supported_enctypes; i++)
184 		if (supported_gss_krb5_enctypes[i].etype == etype)
185 			return &supported_gss_krb5_enctypes[i];
186 	return NULL;
187 }
188 
189 static const void *
190 simple_get_bytes(const void *p, const void *end, void *res, int len)
191 {
192 	const void *q = (const void *)((const char *)p + len);
193 	if (unlikely(q > end || q < p))
194 		return ERR_PTR(-EFAULT);
195 	memcpy(res, p, len);
196 	return q;
197 }
198 
199 static const void *
200 simple_get_netobj(const void *p, const void *end, struct xdr_netobj *res)
201 {
202 	const void *q;
203 	unsigned int len;
204 
205 	p = simple_get_bytes(p, end, &len, sizeof(len));
206 	if (IS_ERR(p))
207 		return p;
208 	q = (const void *)((const char *)p + len);
209 	if (unlikely(q > end || q < p))
210 		return ERR_PTR(-EFAULT);
211 	res->data = kmemdup(p, len, GFP_NOFS);
212 	if (unlikely(res->data == NULL))
213 		return ERR_PTR(-ENOMEM);
214 	res->len = len;
215 	return q;
216 }
217 
218 static inline const void *
219 get_key(const void *p, const void *end,
220 	struct krb5_ctx *ctx, struct crypto_blkcipher **res)
221 {
222 	struct xdr_netobj	key;
223 	int			alg;
224 
225 	p = simple_get_bytes(p, end, &alg, sizeof(alg));
226 	if (IS_ERR(p))
227 		goto out_err;
228 
229 	switch (alg) {
230 	case ENCTYPE_DES_CBC_CRC:
231 	case ENCTYPE_DES_CBC_MD4:
232 	case ENCTYPE_DES_CBC_MD5:
233 		/* Map all these key types to ENCTYPE_DES_CBC_RAW */
234 		alg = ENCTYPE_DES_CBC_RAW;
235 		break;
236 	}
237 
238 	if (!supported_gss_krb5_enctype(alg)) {
239 		printk(KERN_WARNING "gss_kerberos_mech: unsupported "
240 			"encryption key algorithm %d\n", alg);
241 		p = ERR_PTR(-EINVAL);
242 		goto out_err;
243 	}
244 	p = simple_get_netobj(p, end, &key);
245 	if (IS_ERR(p))
246 		goto out_err;
247 
248 	*res = crypto_alloc_blkcipher(ctx->gk5e->encrypt_name, 0,
249 							CRYPTO_ALG_ASYNC);
250 	if (IS_ERR(*res)) {
251 		printk(KERN_WARNING "gss_kerberos_mech: unable to initialize "
252 			"crypto algorithm %s\n", ctx->gk5e->encrypt_name);
253 		*res = NULL;
254 		goto out_err_free_key;
255 	}
256 	if (crypto_blkcipher_setkey(*res, key.data, key.len)) {
257 		printk(KERN_WARNING "gss_kerberos_mech: error setting key for "
258 			"crypto algorithm %s\n", ctx->gk5e->encrypt_name);
259 		goto out_err_free_tfm;
260 	}
261 
262 	kfree(key.data);
263 	return p;
264 
265 out_err_free_tfm:
266 	crypto_free_blkcipher(*res);
267 out_err_free_key:
268 	kfree(key.data);
269 	p = ERR_PTR(-EINVAL);
270 out_err:
271 	return p;
272 }
273 
274 static int
275 gss_import_v1_context(const void *p, const void *end, struct krb5_ctx *ctx)
276 {
277 	int tmp;
278 
279 	p = simple_get_bytes(p, end, &ctx->initiate, sizeof(ctx->initiate));
280 	if (IS_ERR(p))
281 		goto out_err;
282 
283 	/* Old format supports only DES!  Any other enctype uses new format */
284 	ctx->enctype = ENCTYPE_DES_CBC_RAW;
285 
286 	ctx->gk5e = get_gss_krb5_enctype(ctx->enctype);
287 	if (ctx->gk5e == NULL) {
288 		p = ERR_PTR(-EINVAL);
289 		goto out_err;
290 	}
291 
292 	/* The downcall format was designed before we completely understood
293 	 * the uses of the context fields; so it includes some stuff we
294 	 * just give some minimal sanity-checking, and some we ignore
295 	 * completely (like the next twenty bytes): */
296 	if (unlikely(p + 20 > end || p + 20 < p)) {
297 		p = ERR_PTR(-EFAULT);
298 		goto out_err;
299 	}
300 	p += 20;
301 	p = simple_get_bytes(p, end, &tmp, sizeof(tmp));
302 	if (IS_ERR(p))
303 		goto out_err;
304 	if (tmp != SGN_ALG_DES_MAC_MD5) {
305 		p = ERR_PTR(-ENOSYS);
306 		goto out_err;
307 	}
308 	p = simple_get_bytes(p, end, &tmp, sizeof(tmp));
309 	if (IS_ERR(p))
310 		goto out_err;
311 	if (tmp != SEAL_ALG_DES) {
312 		p = ERR_PTR(-ENOSYS);
313 		goto out_err;
314 	}
315 	p = simple_get_bytes(p, end, &ctx->endtime, sizeof(ctx->endtime));
316 	if (IS_ERR(p))
317 		goto out_err;
318 	p = simple_get_bytes(p, end, &ctx->seq_send, sizeof(ctx->seq_send));
319 	if (IS_ERR(p))
320 		goto out_err;
321 	p = simple_get_netobj(p, end, &ctx->mech_used);
322 	if (IS_ERR(p))
323 		goto out_err;
324 	p = get_key(p, end, ctx, &ctx->enc);
325 	if (IS_ERR(p))
326 		goto out_err_free_mech;
327 	p = get_key(p, end, ctx, &ctx->seq);
328 	if (IS_ERR(p))
329 		goto out_err_free_key1;
330 	if (p != end) {
331 		p = ERR_PTR(-EFAULT);
332 		goto out_err_free_key2;
333 	}
334 
335 	return 0;
336 
337 out_err_free_key2:
338 	crypto_free_blkcipher(ctx->seq);
339 out_err_free_key1:
340 	crypto_free_blkcipher(ctx->enc);
341 out_err_free_mech:
342 	kfree(ctx->mech_used.data);
343 out_err:
344 	return PTR_ERR(p);
345 }
346 
347 static struct crypto_blkcipher *
348 context_v2_alloc_cipher(struct krb5_ctx *ctx, const char *cname, u8 *key)
349 {
350 	struct crypto_blkcipher *cp;
351 
352 	cp = crypto_alloc_blkcipher(cname, 0, CRYPTO_ALG_ASYNC);
353 	if (IS_ERR(cp)) {
354 		dprintk("gss_kerberos_mech: unable to initialize "
355 			"crypto algorithm %s\n", cname);
356 		return NULL;
357 	}
358 	if (crypto_blkcipher_setkey(cp, key, ctx->gk5e->keylength)) {
359 		dprintk("gss_kerberos_mech: error setting key for "
360 			"crypto algorithm %s\n", cname);
361 		crypto_free_blkcipher(cp);
362 		return NULL;
363 	}
364 	return cp;
365 }
366 
367 static inline void
368 set_cdata(u8 cdata[GSS_KRB5_K5CLENGTH], u32 usage, u8 seed)
369 {
370 	cdata[0] = (usage>>24)&0xff;
371 	cdata[1] = (usage>>16)&0xff;
372 	cdata[2] = (usage>>8)&0xff;
373 	cdata[3] = usage&0xff;
374 	cdata[4] = seed;
375 }
376 
377 static int
378 context_derive_keys_des3(struct krb5_ctx *ctx, gfp_t gfp_mask)
379 {
380 	struct xdr_netobj c, keyin, keyout;
381 	u8 cdata[GSS_KRB5_K5CLENGTH];
382 	u32 err;
383 
384 	c.len = GSS_KRB5_K5CLENGTH;
385 	c.data = cdata;
386 
387 	keyin.data = ctx->Ksess;
388 	keyin.len = ctx->gk5e->keylength;
389 	keyout.len = ctx->gk5e->keylength;
390 
391 	/* seq uses the raw key */
392 	ctx->seq = context_v2_alloc_cipher(ctx, ctx->gk5e->encrypt_name,
393 					   ctx->Ksess);
394 	if (ctx->seq == NULL)
395 		goto out_err;
396 
397 	ctx->enc = context_v2_alloc_cipher(ctx, ctx->gk5e->encrypt_name,
398 					   ctx->Ksess);
399 	if (ctx->enc == NULL)
400 		goto out_free_seq;
401 
402 	/* derive cksum */
403 	set_cdata(cdata, KG_USAGE_SIGN, KEY_USAGE_SEED_CHECKSUM);
404 	keyout.data = ctx->cksum;
405 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
406 	if (err) {
407 		dprintk("%s: Error %d deriving cksum key\n",
408 			__func__, err);
409 		goto out_free_enc;
410 	}
411 
412 	return 0;
413 
414 out_free_enc:
415 	crypto_free_blkcipher(ctx->enc);
416 out_free_seq:
417 	crypto_free_blkcipher(ctx->seq);
418 out_err:
419 	return -EINVAL;
420 }
421 
422 /*
423  * Note that RC4 depends on deriving keys using the sequence
424  * number or the checksum of a token.  Therefore, the final keys
425  * cannot be calculated until the token is being constructed!
426  */
427 static int
428 context_derive_keys_rc4(struct krb5_ctx *ctx)
429 {
430 	struct crypto_hash *hmac;
431 	char sigkeyconstant[] = "signaturekey";
432 	int slen = strlen(sigkeyconstant) + 1;	/* include null terminator */
433 	struct hash_desc desc;
434 	struct scatterlist sg[1];
435 	int err;
436 
437 	dprintk("RPC:       %s: entered\n", __func__);
438 	/*
439 	 * derive cksum (aka Ksign) key
440 	 */
441 	hmac = crypto_alloc_hash(ctx->gk5e->cksum_name, 0, CRYPTO_ALG_ASYNC);
442 	if (IS_ERR(hmac)) {
443 		dprintk("%s: error %ld allocating hash '%s'\n",
444 			__func__, PTR_ERR(hmac), ctx->gk5e->cksum_name);
445 		err = PTR_ERR(hmac);
446 		goto out_err;
447 	}
448 
449 	err = crypto_hash_setkey(hmac, ctx->Ksess, ctx->gk5e->keylength);
450 	if (err)
451 		goto out_err_free_hmac;
452 
453 	sg_init_table(sg, 1);
454 	sg_set_buf(sg, sigkeyconstant, slen);
455 
456 	desc.tfm = hmac;
457 	desc.flags = 0;
458 
459 	err = crypto_hash_init(&desc);
460 	if (err)
461 		goto out_err_free_hmac;
462 
463 	err = crypto_hash_digest(&desc, sg, slen, ctx->cksum);
464 	if (err)
465 		goto out_err_free_hmac;
466 	/*
467 	 * allocate hash, and blkciphers for data and seqnum encryption
468 	 */
469 	ctx->enc = crypto_alloc_blkcipher(ctx->gk5e->encrypt_name, 0,
470 					  CRYPTO_ALG_ASYNC);
471 	if (IS_ERR(ctx->enc)) {
472 		err = PTR_ERR(ctx->enc);
473 		goto out_err_free_hmac;
474 	}
475 
476 	ctx->seq = crypto_alloc_blkcipher(ctx->gk5e->encrypt_name, 0,
477 					  CRYPTO_ALG_ASYNC);
478 	if (IS_ERR(ctx->seq)) {
479 		crypto_free_blkcipher(ctx->enc);
480 		err = PTR_ERR(ctx->seq);
481 		goto out_err_free_hmac;
482 	}
483 
484 	dprintk("RPC:       %s: returning success\n", __func__);
485 
486 	err = 0;
487 
488 out_err_free_hmac:
489 	crypto_free_hash(hmac);
490 out_err:
491 	dprintk("RPC:       %s: returning %d\n", __func__, err);
492 	return err;
493 }
494 
495 static int
496 context_derive_keys_new(struct krb5_ctx *ctx, gfp_t gfp_mask)
497 {
498 	struct xdr_netobj c, keyin, keyout;
499 	u8 cdata[GSS_KRB5_K5CLENGTH];
500 	u32 err;
501 
502 	c.len = GSS_KRB5_K5CLENGTH;
503 	c.data = cdata;
504 
505 	keyin.data = ctx->Ksess;
506 	keyin.len = ctx->gk5e->keylength;
507 	keyout.len = ctx->gk5e->keylength;
508 
509 	/* initiator seal encryption */
510 	set_cdata(cdata, KG_USAGE_INITIATOR_SEAL, KEY_USAGE_SEED_ENCRYPTION);
511 	keyout.data = ctx->initiator_seal;
512 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
513 	if (err) {
514 		dprintk("%s: Error %d deriving initiator_seal key\n",
515 			__func__, err);
516 		goto out_err;
517 	}
518 	ctx->initiator_enc = context_v2_alloc_cipher(ctx,
519 						     ctx->gk5e->encrypt_name,
520 						     ctx->initiator_seal);
521 	if (ctx->initiator_enc == NULL)
522 		goto out_err;
523 
524 	/* acceptor seal encryption */
525 	set_cdata(cdata, KG_USAGE_ACCEPTOR_SEAL, KEY_USAGE_SEED_ENCRYPTION);
526 	keyout.data = ctx->acceptor_seal;
527 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
528 	if (err) {
529 		dprintk("%s: Error %d deriving acceptor_seal key\n",
530 			__func__, err);
531 		goto out_free_initiator_enc;
532 	}
533 	ctx->acceptor_enc = context_v2_alloc_cipher(ctx,
534 						    ctx->gk5e->encrypt_name,
535 						    ctx->acceptor_seal);
536 	if (ctx->acceptor_enc == NULL)
537 		goto out_free_initiator_enc;
538 
539 	/* initiator sign checksum */
540 	set_cdata(cdata, KG_USAGE_INITIATOR_SIGN, KEY_USAGE_SEED_CHECKSUM);
541 	keyout.data = ctx->initiator_sign;
542 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
543 	if (err) {
544 		dprintk("%s: Error %d deriving initiator_sign key\n",
545 			__func__, err);
546 		goto out_free_acceptor_enc;
547 	}
548 
549 	/* acceptor sign checksum */
550 	set_cdata(cdata, KG_USAGE_ACCEPTOR_SIGN, KEY_USAGE_SEED_CHECKSUM);
551 	keyout.data = ctx->acceptor_sign;
552 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
553 	if (err) {
554 		dprintk("%s: Error %d deriving acceptor_sign key\n",
555 			__func__, err);
556 		goto out_free_acceptor_enc;
557 	}
558 
559 	/* initiator seal integrity */
560 	set_cdata(cdata, KG_USAGE_INITIATOR_SEAL, KEY_USAGE_SEED_INTEGRITY);
561 	keyout.data = ctx->initiator_integ;
562 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
563 	if (err) {
564 		dprintk("%s: Error %d deriving initiator_integ key\n",
565 			__func__, err);
566 		goto out_free_acceptor_enc;
567 	}
568 
569 	/* acceptor seal integrity */
570 	set_cdata(cdata, KG_USAGE_ACCEPTOR_SEAL, KEY_USAGE_SEED_INTEGRITY);
571 	keyout.data = ctx->acceptor_integ;
572 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
573 	if (err) {
574 		dprintk("%s: Error %d deriving acceptor_integ key\n",
575 			__func__, err);
576 		goto out_free_acceptor_enc;
577 	}
578 
579 	switch (ctx->enctype) {
580 	case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
581 	case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
582 		ctx->initiator_enc_aux =
583 			context_v2_alloc_cipher(ctx, "cbc(aes)",
584 						ctx->initiator_seal);
585 		if (ctx->initiator_enc_aux == NULL)
586 			goto out_free_acceptor_enc;
587 		ctx->acceptor_enc_aux =
588 			context_v2_alloc_cipher(ctx, "cbc(aes)",
589 						ctx->acceptor_seal);
590 		if (ctx->acceptor_enc_aux == NULL) {
591 			crypto_free_blkcipher(ctx->initiator_enc_aux);
592 			goto out_free_acceptor_enc;
593 		}
594 	}
595 
596 	return 0;
597 
598 out_free_acceptor_enc:
599 	crypto_free_blkcipher(ctx->acceptor_enc);
600 out_free_initiator_enc:
601 	crypto_free_blkcipher(ctx->initiator_enc);
602 out_err:
603 	return -EINVAL;
604 }
605 
606 static int
607 gss_import_v2_context(const void *p, const void *end, struct krb5_ctx *ctx,
608 		gfp_t gfp_mask)
609 {
610 	int keylen;
611 
612 	p = simple_get_bytes(p, end, &ctx->flags, sizeof(ctx->flags));
613 	if (IS_ERR(p))
614 		goto out_err;
615 	ctx->initiate = ctx->flags & KRB5_CTX_FLAG_INITIATOR;
616 
617 	p = simple_get_bytes(p, end, &ctx->endtime, sizeof(ctx->endtime));
618 	if (IS_ERR(p))
619 		goto out_err;
620 	p = simple_get_bytes(p, end, &ctx->seq_send64, sizeof(ctx->seq_send64));
621 	if (IS_ERR(p))
622 		goto out_err;
623 	/* set seq_send for use by "older" enctypes */
624 	ctx->seq_send = ctx->seq_send64;
625 	if (ctx->seq_send64 != ctx->seq_send) {
626 		dprintk("%s: seq_send64 %lx, seq_send %x overflow?\n", __func__,
627 			(long unsigned)ctx->seq_send64, ctx->seq_send);
628 		p = ERR_PTR(-EINVAL);
629 		goto out_err;
630 	}
631 	p = simple_get_bytes(p, end, &ctx->enctype, sizeof(ctx->enctype));
632 	if (IS_ERR(p))
633 		goto out_err;
634 	/* Map ENCTYPE_DES3_CBC_SHA1 to ENCTYPE_DES3_CBC_RAW */
635 	if (ctx->enctype == ENCTYPE_DES3_CBC_SHA1)
636 		ctx->enctype = ENCTYPE_DES3_CBC_RAW;
637 	ctx->gk5e = get_gss_krb5_enctype(ctx->enctype);
638 	if (ctx->gk5e == NULL) {
639 		dprintk("gss_kerberos_mech: unsupported krb5 enctype %u\n",
640 			ctx->enctype);
641 		p = ERR_PTR(-EINVAL);
642 		goto out_err;
643 	}
644 	keylen = ctx->gk5e->keylength;
645 
646 	p = simple_get_bytes(p, end, ctx->Ksess, keylen);
647 	if (IS_ERR(p))
648 		goto out_err;
649 
650 	if (p != end) {
651 		p = ERR_PTR(-EINVAL);
652 		goto out_err;
653 	}
654 
655 	ctx->mech_used.data = kmemdup(gss_kerberos_mech.gm_oid.data,
656 				      gss_kerberos_mech.gm_oid.len, gfp_mask);
657 	if (unlikely(ctx->mech_used.data == NULL)) {
658 		p = ERR_PTR(-ENOMEM);
659 		goto out_err;
660 	}
661 	ctx->mech_used.len = gss_kerberos_mech.gm_oid.len;
662 
663 	switch (ctx->enctype) {
664 	case ENCTYPE_DES3_CBC_RAW:
665 		return context_derive_keys_des3(ctx, gfp_mask);
666 	case ENCTYPE_ARCFOUR_HMAC:
667 		return context_derive_keys_rc4(ctx);
668 	case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
669 	case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
670 		return context_derive_keys_new(ctx, gfp_mask);
671 	default:
672 		return -EINVAL;
673 	}
674 
675 out_err:
676 	return PTR_ERR(p);
677 }
678 
679 static int
680 gss_import_sec_context_kerberos(const void *p, size_t len,
681 				struct gss_ctx *ctx_id,
682 				gfp_t gfp_mask)
683 {
684 	const void *end = (const void *)((const char *)p + len);
685 	struct  krb5_ctx *ctx;
686 	int ret;
687 
688 	ctx = kzalloc(sizeof(*ctx), gfp_mask);
689 	if (ctx == NULL)
690 		return -ENOMEM;
691 
692 	if (len == 85)
693 		ret = gss_import_v1_context(p, end, ctx);
694 	else
695 		ret = gss_import_v2_context(p, end, ctx, gfp_mask);
696 
697 	if (ret == 0)
698 		ctx_id->internal_ctx_id = ctx;
699 	else
700 		kfree(ctx);
701 
702 	dprintk("RPC:       %s: returning %d\n", __func__, ret);
703 	return ret;
704 }
705 
706 static void
707 gss_delete_sec_context_kerberos(void *internal_ctx) {
708 	struct krb5_ctx *kctx = internal_ctx;
709 
710 	crypto_free_blkcipher(kctx->seq);
711 	crypto_free_blkcipher(kctx->enc);
712 	crypto_free_blkcipher(kctx->acceptor_enc);
713 	crypto_free_blkcipher(kctx->initiator_enc);
714 	crypto_free_blkcipher(kctx->acceptor_enc_aux);
715 	crypto_free_blkcipher(kctx->initiator_enc_aux);
716 	kfree(kctx->mech_used.data);
717 	kfree(kctx);
718 }
719 
720 static const struct gss_api_ops gss_kerberos_ops = {
721 	.gss_import_sec_context	= gss_import_sec_context_kerberos,
722 	.gss_get_mic		= gss_get_mic_kerberos,
723 	.gss_verify_mic		= gss_verify_mic_kerberos,
724 	.gss_wrap		= gss_wrap_kerberos,
725 	.gss_unwrap		= gss_unwrap_kerberos,
726 	.gss_delete_sec_context	= gss_delete_sec_context_kerberos,
727 };
728 
729 static struct pf_desc gss_kerberos_pfs[] = {
730 	[0] = {
731 		.pseudoflavor = RPC_AUTH_GSS_KRB5,
732 		.service = RPC_GSS_SVC_NONE,
733 		.name = "krb5",
734 	},
735 	[1] = {
736 		.pseudoflavor = RPC_AUTH_GSS_KRB5I,
737 		.service = RPC_GSS_SVC_INTEGRITY,
738 		.name = "krb5i",
739 	},
740 	[2] = {
741 		.pseudoflavor = RPC_AUTH_GSS_KRB5P,
742 		.service = RPC_GSS_SVC_PRIVACY,
743 		.name = "krb5p",
744 	},
745 };
746 
747 MODULE_ALIAS("rpc-auth-gss-krb5");
748 MODULE_ALIAS("rpc-auth-gss-krb5i");
749 MODULE_ALIAS("rpc-auth-gss-krb5p");
750 MODULE_ALIAS("rpc-auth-gss-390003");
751 MODULE_ALIAS("rpc-auth-gss-390004");
752 MODULE_ALIAS("rpc-auth-gss-390005");
753 
754 static struct gss_api_mech gss_kerberos_mech = {
755 	.gm_name	= "krb5",
756 	.gm_owner	= THIS_MODULE,
757 	.gm_oid		= {9, (void *)"\x2a\x86\x48\x86\xf7\x12\x01\x02\x02"},
758 	.gm_ops		= &gss_kerberos_ops,
759 	.gm_pf_num	= ARRAY_SIZE(gss_kerberos_pfs),
760 	.gm_pfs		= gss_kerberos_pfs,
761 	.gm_upcall_enctypes = KRB5_SUPPORTED_ENCTYPES,
762 };
763 
764 static int __init init_kerberos_module(void)
765 {
766 	int status;
767 
768 	status = gss_mech_register(&gss_kerberos_mech);
769 	if (status)
770 		printk("Failed to register kerberos gss mechanism!\n");
771 	return status;
772 }
773 
774 static void __exit cleanup_kerberos_module(void)
775 {
776 	gss_mech_unregister(&gss_kerberos_mech);
777 }
778 
779 MODULE_LICENSE("GPL");
780 module_init(init_kerberos_module);
781 module_exit(cleanup_kerberos_module);
782