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 <crypto/hash.h>
38 #include <crypto/skcipher.h>
39 #include <linux/err.h>
40 #include <linux/module.h>
41 #include <linux/init.h>
42 #include <linux/types.h>
43 #include <linux/slab.h>
44 #include <linux/sunrpc/auth.h>
45 #include <linux/sunrpc/gss_krb5.h>
46 #include <linux/sunrpc/xdr.h>
47 #include <linux/sunrpc/gss_krb5_enctypes.h>
48 
49 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
50 # define RPCDBG_FACILITY	RPCDBG_AUTH
51 #endif
52 
53 static struct gss_api_mech gss_kerberos_mech;	/* forward declaration */
54 
55 static const struct gss_krb5_enctype supported_gss_krb5_enctypes[] = {
56 	/*
57 	 * DES (All DES enctypes are mapped to the same gss functionality)
58 	 */
59 	{
60 	  .etype = ENCTYPE_DES_CBC_RAW,
61 	  .ctype = CKSUMTYPE_RSA_MD5,
62 	  .name = "des-cbc-crc",
63 	  .encrypt_name = "cbc(des)",
64 	  .cksum_name = "md5",
65 	  .encrypt = krb5_encrypt,
66 	  .decrypt = krb5_decrypt,
67 	  .mk_key = NULL,
68 	  .signalg = SGN_ALG_DES_MAC_MD5,
69 	  .sealalg = SEAL_ALG_DES,
70 	  .keybytes = 7,
71 	  .keylength = 8,
72 	  .blocksize = 8,
73 	  .conflen = 8,
74 	  .cksumlength = 8,
75 	  .keyed_cksum = 0,
76 	},
77 	/*
78 	 * RC4-HMAC
79 	 */
80 	{
81 	  .etype = ENCTYPE_ARCFOUR_HMAC,
82 	  .ctype = CKSUMTYPE_HMAC_MD5_ARCFOUR,
83 	  .name = "rc4-hmac",
84 	  .encrypt_name = "ecb(arc4)",
85 	  .cksum_name = "hmac(md5)",
86 	  .encrypt = krb5_encrypt,
87 	  .decrypt = krb5_decrypt,
88 	  .mk_key = NULL,
89 	  .signalg = SGN_ALG_HMAC_MD5,
90 	  .sealalg = SEAL_ALG_MICROSOFT_RC4,
91 	  .keybytes = 16,
92 	  .keylength = 16,
93 	  .blocksize = 1,
94 	  .conflen = 8,
95 	  .cksumlength = 8,
96 	  .keyed_cksum = 1,
97 	},
98 	/*
99 	 * 3DES
100 	 */
101 	{
102 	  .etype = ENCTYPE_DES3_CBC_RAW,
103 	  .ctype = CKSUMTYPE_HMAC_SHA1_DES3,
104 	  .name = "des3-hmac-sha1",
105 	  .encrypt_name = "cbc(des3_ede)",
106 	  .cksum_name = "hmac(sha1)",
107 	  .encrypt = krb5_encrypt,
108 	  .decrypt = krb5_decrypt,
109 	  .mk_key = gss_krb5_des3_make_key,
110 	  .signalg = SGN_ALG_HMAC_SHA1_DES3_KD,
111 	  .sealalg = SEAL_ALG_DES3KD,
112 	  .keybytes = 21,
113 	  .keylength = 24,
114 	  .blocksize = 8,
115 	  .conflen = 8,
116 	  .cksumlength = 20,
117 	  .keyed_cksum = 1,
118 	},
119 	/*
120 	 * AES128
121 	 */
122 	{
123 	  .etype = ENCTYPE_AES128_CTS_HMAC_SHA1_96,
124 	  .ctype = CKSUMTYPE_HMAC_SHA1_96_AES128,
125 	  .name = "aes128-cts",
126 	  .encrypt_name = "cts(cbc(aes))",
127 	  .cksum_name = "hmac(sha1)",
128 	  .encrypt = krb5_encrypt,
129 	  .decrypt = krb5_decrypt,
130 	  .mk_key = gss_krb5_aes_make_key,
131 	  .encrypt_v2 = gss_krb5_aes_encrypt,
132 	  .decrypt_v2 = gss_krb5_aes_decrypt,
133 	  .signalg = -1,
134 	  .sealalg = -1,
135 	  .keybytes = 16,
136 	  .keylength = 16,
137 	  .blocksize = 16,
138 	  .conflen = 16,
139 	  .cksumlength = 12,
140 	  .keyed_cksum = 1,
141 	},
142 	/*
143 	 * AES256
144 	 */
145 	{
146 	  .etype = ENCTYPE_AES256_CTS_HMAC_SHA1_96,
147 	  .ctype = CKSUMTYPE_HMAC_SHA1_96_AES256,
148 	  .name = "aes256-cts",
149 	  .encrypt_name = "cts(cbc(aes))",
150 	  .cksum_name = "hmac(sha1)",
151 	  .encrypt = krb5_encrypt,
152 	  .decrypt = krb5_decrypt,
153 	  .mk_key = gss_krb5_aes_make_key,
154 	  .encrypt_v2 = gss_krb5_aes_encrypt,
155 	  .decrypt_v2 = gss_krb5_aes_decrypt,
156 	  .signalg = -1,
157 	  .sealalg = -1,
158 	  .keybytes = 32,
159 	  .keylength = 32,
160 	  .blocksize = 16,
161 	  .conflen = 16,
162 	  .cksumlength = 12,
163 	  .keyed_cksum = 1,
164 	},
165 };
166 
167 static const int num_supported_enctypes =
168 	ARRAY_SIZE(supported_gss_krb5_enctypes);
169 
170 static int
171 supported_gss_krb5_enctype(int etype)
172 {
173 	int i;
174 	for (i = 0; i < num_supported_enctypes; i++)
175 		if (supported_gss_krb5_enctypes[i].etype == etype)
176 			return 1;
177 	return 0;
178 }
179 
180 static const struct gss_krb5_enctype *
181 get_gss_krb5_enctype(int etype)
182 {
183 	int i;
184 	for (i = 0; i < num_supported_enctypes; i++)
185 		if (supported_gss_krb5_enctypes[i].etype == etype)
186 			return &supported_gss_krb5_enctypes[i];
187 	return NULL;
188 }
189 
190 static const void *
191 simple_get_bytes(const void *p, const void *end, void *res, int len)
192 {
193 	const void *q = (const void *)((const char *)p + len);
194 	if (unlikely(q > end || q < p))
195 		return ERR_PTR(-EFAULT);
196 	memcpy(res, p, len);
197 	return q;
198 }
199 
200 static const void *
201 simple_get_netobj(const void *p, const void *end, struct xdr_netobj *res)
202 {
203 	const void *q;
204 	unsigned int len;
205 
206 	p = simple_get_bytes(p, end, &len, sizeof(len));
207 	if (IS_ERR(p))
208 		return p;
209 	q = (const void *)((const char *)p + len);
210 	if (unlikely(q > end || q < p))
211 		return ERR_PTR(-EFAULT);
212 	res->data = kmemdup(p, len, GFP_NOFS);
213 	if (unlikely(res->data == NULL))
214 		return ERR_PTR(-ENOMEM);
215 	res->len = len;
216 	return q;
217 }
218 
219 static inline const void *
220 get_key(const void *p, const void *end,
221 	struct krb5_ctx *ctx, struct crypto_skcipher **res)
222 {
223 	struct xdr_netobj	key;
224 	int			alg;
225 
226 	p = simple_get_bytes(p, end, &alg, sizeof(alg));
227 	if (IS_ERR(p))
228 		goto out_err;
229 
230 	switch (alg) {
231 	case ENCTYPE_DES_CBC_CRC:
232 	case ENCTYPE_DES_CBC_MD4:
233 	case ENCTYPE_DES_CBC_MD5:
234 		/* Map all these key types to ENCTYPE_DES_CBC_RAW */
235 		alg = ENCTYPE_DES_CBC_RAW;
236 		break;
237 	}
238 
239 	if (!supported_gss_krb5_enctype(alg)) {
240 		printk(KERN_WARNING "gss_kerberos_mech: unsupported "
241 			"encryption key algorithm %d\n", alg);
242 		p = ERR_PTR(-EINVAL);
243 		goto out_err;
244 	}
245 	p = simple_get_netobj(p, end, &key);
246 	if (IS_ERR(p))
247 		goto out_err;
248 
249 	*res = crypto_alloc_skcipher(ctx->gk5e->encrypt_name, 0,
250 							CRYPTO_ALG_ASYNC);
251 	if (IS_ERR(*res)) {
252 		printk(KERN_WARNING "gss_kerberos_mech: unable to initialize "
253 			"crypto algorithm %s\n", ctx->gk5e->encrypt_name);
254 		*res = NULL;
255 		goto out_err_free_key;
256 	}
257 	if (crypto_skcipher_setkey(*res, key.data, key.len)) {
258 		printk(KERN_WARNING "gss_kerberos_mech: error setting key for "
259 			"crypto algorithm %s\n", ctx->gk5e->encrypt_name);
260 		goto out_err_free_tfm;
261 	}
262 
263 	kfree(key.data);
264 	return p;
265 
266 out_err_free_tfm:
267 	crypto_free_skcipher(*res);
268 out_err_free_key:
269 	kfree(key.data);
270 	p = ERR_PTR(-EINVAL);
271 out_err:
272 	return p;
273 }
274 
275 static int
276 gss_import_v1_context(const void *p, const void *end, struct krb5_ctx *ctx)
277 {
278 	int tmp;
279 
280 	p = simple_get_bytes(p, end, &ctx->initiate, sizeof(ctx->initiate));
281 	if (IS_ERR(p))
282 		goto out_err;
283 
284 	/* Old format supports only DES!  Any other enctype uses new format */
285 	ctx->enctype = ENCTYPE_DES_CBC_RAW;
286 
287 	ctx->gk5e = get_gss_krb5_enctype(ctx->enctype);
288 	if (ctx->gk5e == NULL) {
289 		p = ERR_PTR(-EINVAL);
290 		goto out_err;
291 	}
292 
293 	/* The downcall format was designed before we completely understood
294 	 * the uses of the context fields; so it includes some stuff we
295 	 * just give some minimal sanity-checking, and some we ignore
296 	 * completely (like the next twenty bytes): */
297 	if (unlikely(p + 20 > end || p + 20 < p)) {
298 		p = ERR_PTR(-EFAULT);
299 		goto out_err;
300 	}
301 	p += 20;
302 	p = simple_get_bytes(p, end, &tmp, sizeof(tmp));
303 	if (IS_ERR(p))
304 		goto out_err;
305 	if (tmp != SGN_ALG_DES_MAC_MD5) {
306 		p = ERR_PTR(-ENOSYS);
307 		goto out_err;
308 	}
309 	p = simple_get_bytes(p, end, &tmp, sizeof(tmp));
310 	if (IS_ERR(p))
311 		goto out_err;
312 	if (tmp != SEAL_ALG_DES) {
313 		p = ERR_PTR(-ENOSYS);
314 		goto out_err;
315 	}
316 	p = simple_get_bytes(p, end, &ctx->endtime, sizeof(ctx->endtime));
317 	if (IS_ERR(p))
318 		goto out_err;
319 	p = simple_get_bytes(p, end, &ctx->seq_send, sizeof(ctx->seq_send));
320 	if (IS_ERR(p))
321 		goto out_err;
322 	p = simple_get_netobj(p, end, &ctx->mech_used);
323 	if (IS_ERR(p))
324 		goto out_err;
325 	p = get_key(p, end, ctx, &ctx->enc);
326 	if (IS_ERR(p))
327 		goto out_err_free_mech;
328 	p = get_key(p, end, ctx, &ctx->seq);
329 	if (IS_ERR(p))
330 		goto out_err_free_key1;
331 	if (p != end) {
332 		p = ERR_PTR(-EFAULT);
333 		goto out_err_free_key2;
334 	}
335 
336 	return 0;
337 
338 out_err_free_key2:
339 	crypto_free_skcipher(ctx->seq);
340 out_err_free_key1:
341 	crypto_free_skcipher(ctx->enc);
342 out_err_free_mech:
343 	kfree(ctx->mech_used.data);
344 out_err:
345 	return PTR_ERR(p);
346 }
347 
348 static struct crypto_skcipher *
349 context_v2_alloc_cipher(struct krb5_ctx *ctx, const char *cname, u8 *key)
350 {
351 	struct crypto_skcipher *cp;
352 
353 	cp = crypto_alloc_skcipher(cname, 0, CRYPTO_ALG_ASYNC);
354 	if (IS_ERR(cp)) {
355 		dprintk("gss_kerberos_mech: unable to initialize "
356 			"crypto algorithm %s\n", cname);
357 		return NULL;
358 	}
359 	if (crypto_skcipher_setkey(cp, key, ctx->gk5e->keylength)) {
360 		dprintk("gss_kerberos_mech: error setting key for "
361 			"crypto algorithm %s\n", cname);
362 		crypto_free_skcipher(cp);
363 		return NULL;
364 	}
365 	return cp;
366 }
367 
368 static inline void
369 set_cdata(u8 cdata[GSS_KRB5_K5CLENGTH], u32 usage, u8 seed)
370 {
371 	cdata[0] = (usage>>24)&0xff;
372 	cdata[1] = (usage>>16)&0xff;
373 	cdata[2] = (usage>>8)&0xff;
374 	cdata[3] = usage&0xff;
375 	cdata[4] = seed;
376 }
377 
378 static int
379 context_derive_keys_des3(struct krb5_ctx *ctx, gfp_t gfp_mask)
380 {
381 	struct xdr_netobj c, keyin, keyout;
382 	u8 cdata[GSS_KRB5_K5CLENGTH];
383 	u32 err;
384 
385 	c.len = GSS_KRB5_K5CLENGTH;
386 	c.data = cdata;
387 
388 	keyin.data = ctx->Ksess;
389 	keyin.len = ctx->gk5e->keylength;
390 	keyout.len = ctx->gk5e->keylength;
391 
392 	/* seq uses the raw key */
393 	ctx->seq = context_v2_alloc_cipher(ctx, ctx->gk5e->encrypt_name,
394 					   ctx->Ksess);
395 	if (ctx->seq == NULL)
396 		goto out_err;
397 
398 	ctx->enc = context_v2_alloc_cipher(ctx, ctx->gk5e->encrypt_name,
399 					   ctx->Ksess);
400 	if (ctx->enc == NULL)
401 		goto out_free_seq;
402 
403 	/* derive cksum */
404 	set_cdata(cdata, KG_USAGE_SIGN, KEY_USAGE_SEED_CHECKSUM);
405 	keyout.data = ctx->cksum;
406 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
407 	if (err) {
408 		dprintk("%s: Error %d deriving cksum key\n",
409 			__func__, err);
410 		goto out_free_enc;
411 	}
412 
413 	return 0;
414 
415 out_free_enc:
416 	crypto_free_skcipher(ctx->enc);
417 out_free_seq:
418 	crypto_free_skcipher(ctx->seq);
419 out_err:
420 	return -EINVAL;
421 }
422 
423 /*
424  * Note that RC4 depends on deriving keys using the sequence
425  * number or the checksum of a token.  Therefore, the final keys
426  * cannot be calculated until the token is being constructed!
427  */
428 static int
429 context_derive_keys_rc4(struct krb5_ctx *ctx)
430 {
431 	struct crypto_shash *hmac;
432 	char sigkeyconstant[] = "signaturekey";
433 	int slen = strlen(sigkeyconstant) + 1;	/* include null terminator */
434 	struct shash_desc *desc;
435 	int err;
436 
437 	dprintk("RPC:       %s: entered\n", __func__);
438 	/*
439 	 * derive cksum (aka Ksign) key
440 	 */
441 	hmac = crypto_alloc_shash(ctx->gk5e->cksum_name, 0, 0);
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_shash_setkey(hmac, ctx->Ksess, ctx->gk5e->keylength);
450 	if (err)
451 		goto out_err_free_hmac;
452 
453 
454 	desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(hmac), GFP_NOFS);
455 	if (!desc) {
456 		dprintk("%s: failed to allocate hash descriptor for '%s'\n",
457 			__func__, ctx->gk5e->cksum_name);
458 		err = -ENOMEM;
459 		goto out_err_free_hmac;
460 	}
461 
462 	desc->tfm = hmac;
463 	desc->flags = 0;
464 
465 	err = crypto_shash_digest(desc, sigkeyconstant, slen, ctx->cksum);
466 	kzfree(desc);
467 	if (err)
468 		goto out_err_free_hmac;
469 	/*
470 	 * allocate hash, and skciphers for data and seqnum encryption
471 	 */
472 	ctx->enc = crypto_alloc_skcipher(ctx->gk5e->encrypt_name, 0,
473 					 CRYPTO_ALG_ASYNC);
474 	if (IS_ERR(ctx->enc)) {
475 		err = PTR_ERR(ctx->enc);
476 		goto out_err_free_hmac;
477 	}
478 
479 	ctx->seq = crypto_alloc_skcipher(ctx->gk5e->encrypt_name, 0,
480 					 CRYPTO_ALG_ASYNC);
481 	if (IS_ERR(ctx->seq)) {
482 		crypto_free_skcipher(ctx->enc);
483 		err = PTR_ERR(ctx->seq);
484 		goto out_err_free_hmac;
485 	}
486 
487 	dprintk("RPC:       %s: returning success\n", __func__);
488 
489 	err = 0;
490 
491 out_err_free_hmac:
492 	crypto_free_shash(hmac);
493 out_err:
494 	dprintk("RPC:       %s: returning %d\n", __func__, err);
495 	return err;
496 }
497 
498 static int
499 context_derive_keys_new(struct krb5_ctx *ctx, gfp_t gfp_mask)
500 {
501 	struct xdr_netobj c, keyin, keyout;
502 	u8 cdata[GSS_KRB5_K5CLENGTH];
503 	u32 err;
504 
505 	c.len = GSS_KRB5_K5CLENGTH;
506 	c.data = cdata;
507 
508 	keyin.data = ctx->Ksess;
509 	keyin.len = ctx->gk5e->keylength;
510 	keyout.len = ctx->gk5e->keylength;
511 
512 	/* initiator seal encryption */
513 	set_cdata(cdata, KG_USAGE_INITIATOR_SEAL, KEY_USAGE_SEED_ENCRYPTION);
514 	keyout.data = ctx->initiator_seal;
515 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
516 	if (err) {
517 		dprintk("%s: Error %d deriving initiator_seal key\n",
518 			__func__, err);
519 		goto out_err;
520 	}
521 	ctx->initiator_enc = context_v2_alloc_cipher(ctx,
522 						     ctx->gk5e->encrypt_name,
523 						     ctx->initiator_seal);
524 	if (ctx->initiator_enc == NULL)
525 		goto out_err;
526 
527 	/* acceptor seal encryption */
528 	set_cdata(cdata, KG_USAGE_ACCEPTOR_SEAL, KEY_USAGE_SEED_ENCRYPTION);
529 	keyout.data = ctx->acceptor_seal;
530 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
531 	if (err) {
532 		dprintk("%s: Error %d deriving acceptor_seal key\n",
533 			__func__, err);
534 		goto out_free_initiator_enc;
535 	}
536 	ctx->acceptor_enc = context_v2_alloc_cipher(ctx,
537 						    ctx->gk5e->encrypt_name,
538 						    ctx->acceptor_seal);
539 	if (ctx->acceptor_enc == NULL)
540 		goto out_free_initiator_enc;
541 
542 	/* initiator sign checksum */
543 	set_cdata(cdata, KG_USAGE_INITIATOR_SIGN, KEY_USAGE_SEED_CHECKSUM);
544 	keyout.data = ctx->initiator_sign;
545 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
546 	if (err) {
547 		dprintk("%s: Error %d deriving initiator_sign key\n",
548 			__func__, err);
549 		goto out_free_acceptor_enc;
550 	}
551 
552 	/* acceptor sign checksum */
553 	set_cdata(cdata, KG_USAGE_ACCEPTOR_SIGN, KEY_USAGE_SEED_CHECKSUM);
554 	keyout.data = ctx->acceptor_sign;
555 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
556 	if (err) {
557 		dprintk("%s: Error %d deriving acceptor_sign key\n",
558 			__func__, err);
559 		goto out_free_acceptor_enc;
560 	}
561 
562 	/* initiator seal integrity */
563 	set_cdata(cdata, KG_USAGE_INITIATOR_SEAL, KEY_USAGE_SEED_INTEGRITY);
564 	keyout.data = ctx->initiator_integ;
565 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
566 	if (err) {
567 		dprintk("%s: Error %d deriving initiator_integ key\n",
568 			__func__, err);
569 		goto out_free_acceptor_enc;
570 	}
571 
572 	/* acceptor seal integrity */
573 	set_cdata(cdata, KG_USAGE_ACCEPTOR_SEAL, KEY_USAGE_SEED_INTEGRITY);
574 	keyout.data = ctx->acceptor_integ;
575 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
576 	if (err) {
577 		dprintk("%s: Error %d deriving acceptor_integ key\n",
578 			__func__, err);
579 		goto out_free_acceptor_enc;
580 	}
581 
582 	switch (ctx->enctype) {
583 	case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
584 	case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
585 		ctx->initiator_enc_aux =
586 			context_v2_alloc_cipher(ctx, "cbc(aes)",
587 						ctx->initiator_seal);
588 		if (ctx->initiator_enc_aux == NULL)
589 			goto out_free_acceptor_enc;
590 		ctx->acceptor_enc_aux =
591 			context_v2_alloc_cipher(ctx, "cbc(aes)",
592 						ctx->acceptor_seal);
593 		if (ctx->acceptor_enc_aux == NULL) {
594 			crypto_free_skcipher(ctx->initiator_enc_aux);
595 			goto out_free_acceptor_enc;
596 		}
597 	}
598 
599 	return 0;
600 
601 out_free_acceptor_enc:
602 	crypto_free_skcipher(ctx->acceptor_enc);
603 out_free_initiator_enc:
604 	crypto_free_skcipher(ctx->initiator_enc);
605 out_err:
606 	return -EINVAL;
607 }
608 
609 static int
610 gss_import_v2_context(const void *p, const void *end, struct krb5_ctx *ctx,
611 		gfp_t gfp_mask)
612 {
613 	int keylen;
614 
615 	p = simple_get_bytes(p, end, &ctx->flags, sizeof(ctx->flags));
616 	if (IS_ERR(p))
617 		goto out_err;
618 	ctx->initiate = ctx->flags & KRB5_CTX_FLAG_INITIATOR;
619 
620 	p = simple_get_bytes(p, end, &ctx->endtime, sizeof(ctx->endtime));
621 	if (IS_ERR(p))
622 		goto out_err;
623 	p = simple_get_bytes(p, end, &ctx->seq_send64, sizeof(ctx->seq_send64));
624 	if (IS_ERR(p))
625 		goto out_err;
626 	/* set seq_send for use by "older" enctypes */
627 	ctx->seq_send = ctx->seq_send64;
628 	if (ctx->seq_send64 != ctx->seq_send) {
629 		dprintk("%s: seq_send64 %lx, seq_send %x overflow?\n", __func__,
630 			(unsigned long)ctx->seq_send64, ctx->seq_send);
631 		p = ERR_PTR(-EINVAL);
632 		goto out_err;
633 	}
634 	p = simple_get_bytes(p, end, &ctx->enctype, sizeof(ctx->enctype));
635 	if (IS_ERR(p))
636 		goto out_err;
637 	/* Map ENCTYPE_DES3_CBC_SHA1 to ENCTYPE_DES3_CBC_RAW */
638 	if (ctx->enctype == ENCTYPE_DES3_CBC_SHA1)
639 		ctx->enctype = ENCTYPE_DES3_CBC_RAW;
640 	ctx->gk5e = get_gss_krb5_enctype(ctx->enctype);
641 	if (ctx->gk5e == NULL) {
642 		dprintk("gss_kerberos_mech: unsupported krb5 enctype %u\n",
643 			ctx->enctype);
644 		p = ERR_PTR(-EINVAL);
645 		goto out_err;
646 	}
647 	keylen = ctx->gk5e->keylength;
648 
649 	p = simple_get_bytes(p, end, ctx->Ksess, keylen);
650 	if (IS_ERR(p))
651 		goto out_err;
652 
653 	if (p != end) {
654 		p = ERR_PTR(-EINVAL);
655 		goto out_err;
656 	}
657 
658 	ctx->mech_used.data = kmemdup(gss_kerberos_mech.gm_oid.data,
659 				      gss_kerberos_mech.gm_oid.len, gfp_mask);
660 	if (unlikely(ctx->mech_used.data == NULL)) {
661 		p = ERR_PTR(-ENOMEM);
662 		goto out_err;
663 	}
664 	ctx->mech_used.len = gss_kerberos_mech.gm_oid.len;
665 
666 	switch (ctx->enctype) {
667 	case ENCTYPE_DES3_CBC_RAW:
668 		return context_derive_keys_des3(ctx, gfp_mask);
669 	case ENCTYPE_ARCFOUR_HMAC:
670 		return context_derive_keys_rc4(ctx);
671 	case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
672 	case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
673 		return context_derive_keys_new(ctx, gfp_mask);
674 	default:
675 		return -EINVAL;
676 	}
677 
678 out_err:
679 	return PTR_ERR(p);
680 }
681 
682 static int
683 gss_import_sec_context_kerberos(const void *p, size_t len,
684 				struct gss_ctx *ctx_id,
685 				time_t *endtime,
686 				gfp_t gfp_mask)
687 {
688 	const void *end = (const void *)((const char *)p + len);
689 	struct  krb5_ctx *ctx;
690 	int ret;
691 
692 	ctx = kzalloc(sizeof(*ctx), gfp_mask);
693 	if (ctx == NULL)
694 		return -ENOMEM;
695 
696 	if (len == 85)
697 		ret = gss_import_v1_context(p, end, ctx);
698 	else
699 		ret = gss_import_v2_context(p, end, ctx, gfp_mask);
700 
701 	if (ret == 0) {
702 		ctx_id->internal_ctx_id = ctx;
703 		if (endtime)
704 			*endtime = ctx->endtime;
705 	} else
706 		kfree(ctx);
707 
708 	dprintk("RPC:       %s: returning %d\n", __func__, ret);
709 	return ret;
710 }
711 
712 static void
713 gss_delete_sec_context_kerberos(void *internal_ctx) {
714 	struct krb5_ctx *kctx = internal_ctx;
715 
716 	crypto_free_skcipher(kctx->seq);
717 	crypto_free_skcipher(kctx->enc);
718 	crypto_free_skcipher(kctx->acceptor_enc);
719 	crypto_free_skcipher(kctx->initiator_enc);
720 	crypto_free_skcipher(kctx->acceptor_enc_aux);
721 	crypto_free_skcipher(kctx->initiator_enc_aux);
722 	kfree(kctx->mech_used.data);
723 	kfree(kctx);
724 }
725 
726 static const struct gss_api_ops gss_kerberos_ops = {
727 	.gss_import_sec_context	= gss_import_sec_context_kerberos,
728 	.gss_get_mic		= gss_get_mic_kerberos,
729 	.gss_verify_mic		= gss_verify_mic_kerberos,
730 	.gss_wrap		= gss_wrap_kerberos,
731 	.gss_unwrap		= gss_unwrap_kerberos,
732 	.gss_delete_sec_context	= gss_delete_sec_context_kerberos,
733 };
734 
735 static struct pf_desc gss_kerberos_pfs[] = {
736 	[0] = {
737 		.pseudoflavor = RPC_AUTH_GSS_KRB5,
738 		.qop = GSS_C_QOP_DEFAULT,
739 		.service = RPC_GSS_SVC_NONE,
740 		.name = "krb5",
741 	},
742 	[1] = {
743 		.pseudoflavor = RPC_AUTH_GSS_KRB5I,
744 		.qop = GSS_C_QOP_DEFAULT,
745 		.service = RPC_GSS_SVC_INTEGRITY,
746 		.name = "krb5i",
747 		.datatouch = true,
748 	},
749 	[2] = {
750 		.pseudoflavor = RPC_AUTH_GSS_KRB5P,
751 		.qop = GSS_C_QOP_DEFAULT,
752 		.service = RPC_GSS_SVC_PRIVACY,
753 		.name = "krb5p",
754 		.datatouch = true,
755 	},
756 };
757 
758 MODULE_ALIAS("rpc-auth-gss-krb5");
759 MODULE_ALIAS("rpc-auth-gss-krb5i");
760 MODULE_ALIAS("rpc-auth-gss-krb5p");
761 MODULE_ALIAS("rpc-auth-gss-390003");
762 MODULE_ALIAS("rpc-auth-gss-390004");
763 MODULE_ALIAS("rpc-auth-gss-390005");
764 MODULE_ALIAS("rpc-auth-gss-1.2.840.113554.1.2.2");
765 
766 static struct gss_api_mech gss_kerberos_mech = {
767 	.gm_name	= "krb5",
768 	.gm_owner	= THIS_MODULE,
769 	.gm_oid		= { 9, "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02" },
770 	.gm_ops		= &gss_kerberos_ops,
771 	.gm_pf_num	= ARRAY_SIZE(gss_kerberos_pfs),
772 	.gm_pfs		= gss_kerberos_pfs,
773 	.gm_upcall_enctypes = KRB5_SUPPORTED_ENCTYPES,
774 };
775 
776 static int __init init_kerberos_module(void)
777 {
778 	int status;
779 
780 	status = gss_mech_register(&gss_kerberos_mech);
781 	if (status)
782 		printk("Failed to register kerberos gss mechanism!\n");
783 	return status;
784 }
785 
786 static void __exit cleanup_kerberos_module(void)
787 {
788 	gss_mech_unregister(&gss_kerberos_mech);
789 }
790 
791 MODULE_LICENSE("GPL");
792 module_init(init_kerberos_module);
793 module_exit(cleanup_kerberos_module);
794