xref: /openbmc/linux/net/sunrpc/auth_gss/gss_krb5_mech.c (revision baa7eb025ab14f3cba2e35c0a8648f9c9f01d24f)
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 
47 #ifdef RPC_DEBUG
48 # define RPCDBG_FACILITY	RPCDBG_AUTH
49 #endif
50 
51 static struct gss_api_mech gss_kerberos_mech;	/* forward declaration */
52 
53 static const struct gss_krb5_enctype supported_gss_krb5_enctypes[] = {
54 	/*
55 	 * DES (All DES enctypes are mapped to the same gss functionality)
56 	 */
57 	{
58 	  .etype = ENCTYPE_DES_CBC_RAW,
59 	  .ctype = CKSUMTYPE_RSA_MD5,
60 	  .name = "des-cbc-crc",
61 	  .encrypt_name = "cbc(des)",
62 	  .cksum_name = "md5",
63 	  .encrypt = krb5_encrypt,
64 	  .decrypt = krb5_decrypt,
65 	  .mk_key = NULL,
66 	  .signalg = SGN_ALG_DES_MAC_MD5,
67 	  .sealalg = SEAL_ALG_DES,
68 	  .keybytes = 7,
69 	  .keylength = 8,
70 	  .blocksize = 8,
71 	  .conflen = 8,
72 	  .cksumlength = 8,
73 	  .keyed_cksum = 0,
74 	},
75 	/*
76 	 * RC4-HMAC
77 	 */
78 	{
79 	  .etype = ENCTYPE_ARCFOUR_HMAC,
80 	  .ctype = CKSUMTYPE_HMAC_MD5_ARCFOUR,
81 	  .name = "rc4-hmac",
82 	  .encrypt_name = "ecb(arc4)",
83 	  .cksum_name = "hmac(md5)",
84 	  .encrypt = krb5_encrypt,
85 	  .decrypt = krb5_decrypt,
86 	  .mk_key = NULL,
87 	  .signalg = SGN_ALG_HMAC_MD5,
88 	  .sealalg = SEAL_ALG_MICROSOFT_RC4,
89 	  .keybytes = 16,
90 	  .keylength = 16,
91 	  .blocksize = 1,
92 	  .conflen = 8,
93 	  .cksumlength = 8,
94 	  .keyed_cksum = 1,
95 	},
96 	/*
97 	 * 3DES
98 	 */
99 	{
100 	  .etype = ENCTYPE_DES3_CBC_RAW,
101 	  .ctype = CKSUMTYPE_HMAC_SHA1_DES3,
102 	  .name = "des3-hmac-sha1",
103 	  .encrypt_name = "cbc(des3_ede)",
104 	  .cksum_name = "hmac(sha1)",
105 	  .encrypt = krb5_encrypt,
106 	  .decrypt = krb5_decrypt,
107 	  .mk_key = gss_krb5_des3_make_key,
108 	  .signalg = SGN_ALG_HMAC_SHA1_DES3_KD,
109 	  .sealalg = SEAL_ALG_DES3KD,
110 	  .keybytes = 21,
111 	  .keylength = 24,
112 	  .blocksize = 8,
113 	  .conflen = 8,
114 	  .cksumlength = 20,
115 	  .keyed_cksum = 1,
116 	},
117 	/*
118 	 * AES128
119 	 */
120 	{
121 	  .etype = ENCTYPE_AES128_CTS_HMAC_SHA1_96,
122 	  .ctype = CKSUMTYPE_HMAC_SHA1_96_AES128,
123 	  .name = "aes128-cts",
124 	  .encrypt_name = "cts(cbc(aes))",
125 	  .cksum_name = "hmac(sha1)",
126 	  .encrypt = krb5_encrypt,
127 	  .decrypt = krb5_decrypt,
128 	  .mk_key = gss_krb5_aes_make_key,
129 	  .encrypt_v2 = gss_krb5_aes_encrypt,
130 	  .decrypt_v2 = gss_krb5_aes_decrypt,
131 	  .signalg = -1,
132 	  .sealalg = -1,
133 	  .keybytes = 16,
134 	  .keylength = 16,
135 	  .blocksize = 16,
136 	  .conflen = 16,
137 	  .cksumlength = 12,
138 	  .keyed_cksum = 1,
139 	},
140 	/*
141 	 * AES256
142 	 */
143 	{
144 	  .etype = ENCTYPE_AES256_CTS_HMAC_SHA1_96,
145 	  .ctype = CKSUMTYPE_HMAC_SHA1_96_AES256,
146 	  .name = "aes256-cts",
147 	  .encrypt_name = "cts(cbc(aes))",
148 	  .cksum_name = "hmac(sha1)",
149 	  .encrypt = krb5_encrypt,
150 	  .decrypt = krb5_decrypt,
151 	  .mk_key = gss_krb5_aes_make_key,
152 	  .encrypt_v2 = gss_krb5_aes_encrypt,
153 	  .decrypt_v2 = gss_krb5_aes_decrypt,
154 	  .signalg = -1,
155 	  .sealalg = -1,
156 	  .keybytes = 32,
157 	  .keylength = 32,
158 	  .blocksize = 16,
159 	  .conflen = 16,
160 	  .cksumlength = 12,
161 	  .keyed_cksum = 1,
162 	},
163 };
164 
165 static const int num_supported_enctypes =
166 	ARRAY_SIZE(supported_gss_krb5_enctypes);
167 
168 static int
169 supported_gss_krb5_enctype(int etype)
170 {
171 	int i;
172 	for (i = 0; i < num_supported_enctypes; i++)
173 		if (supported_gss_krb5_enctypes[i].etype == etype)
174 			return 1;
175 	return 0;
176 }
177 
178 static const struct gss_krb5_enctype *
179 get_gss_krb5_enctype(int etype)
180 {
181 	int i;
182 	for (i = 0; i < num_supported_enctypes; i++)
183 		if (supported_gss_krb5_enctypes[i].etype == etype)
184 			return &supported_gss_krb5_enctypes[i];
185 	return NULL;
186 }
187 
188 static const void *
189 simple_get_bytes(const void *p, const void *end, void *res, int len)
190 {
191 	const void *q = (const void *)((const char *)p + len);
192 	if (unlikely(q > end || q < p))
193 		return ERR_PTR(-EFAULT);
194 	memcpy(res, p, len);
195 	return q;
196 }
197 
198 static const void *
199 simple_get_netobj(const void *p, const void *end, struct xdr_netobj *res)
200 {
201 	const void *q;
202 	unsigned int len;
203 
204 	p = simple_get_bytes(p, end, &len, sizeof(len));
205 	if (IS_ERR(p))
206 		return p;
207 	q = (const void *)((const char *)p + len);
208 	if (unlikely(q > end || q < p))
209 		return ERR_PTR(-EFAULT);
210 	res->data = kmemdup(p, len, GFP_NOFS);
211 	if (unlikely(res->data == NULL))
212 		return ERR_PTR(-ENOMEM);
213 	res->len = len;
214 	return q;
215 }
216 
217 static inline const void *
218 get_key(const void *p, const void *end,
219 	struct krb5_ctx *ctx, struct crypto_blkcipher **res)
220 {
221 	struct xdr_netobj	key;
222 	int			alg;
223 
224 	p = simple_get_bytes(p, end, &alg, sizeof(alg));
225 	if (IS_ERR(p))
226 		goto out_err;
227 
228 	switch (alg) {
229 	case ENCTYPE_DES_CBC_CRC:
230 	case ENCTYPE_DES_CBC_MD4:
231 	case ENCTYPE_DES_CBC_MD5:
232 		/* Map all these key types to ENCTYPE_DES_CBC_RAW */
233 		alg = ENCTYPE_DES_CBC_RAW;
234 		break;
235 	}
236 
237 	if (!supported_gss_krb5_enctype(alg)) {
238 		printk(KERN_WARNING "gss_kerberos_mech: unsupported "
239 			"encryption key algorithm %d\n", alg);
240 		p = ERR_PTR(-EINVAL);
241 		goto out_err;
242 	}
243 	p = simple_get_netobj(p, end, &key);
244 	if (IS_ERR(p))
245 		goto out_err;
246 
247 	*res = crypto_alloc_blkcipher(ctx->gk5e->encrypt_name, 0,
248 							CRYPTO_ALG_ASYNC);
249 	if (IS_ERR(*res)) {
250 		printk(KERN_WARNING "gss_kerberos_mech: unable to initialize "
251 			"crypto algorithm %s\n", ctx->gk5e->encrypt_name);
252 		*res = NULL;
253 		goto out_err_free_key;
254 	}
255 	if (crypto_blkcipher_setkey(*res, key.data, key.len)) {
256 		printk(KERN_WARNING "gss_kerberos_mech: error setting key for "
257 			"crypto algorithm %s\n", ctx->gk5e->encrypt_name);
258 		goto out_err_free_tfm;
259 	}
260 
261 	kfree(key.data);
262 	return p;
263 
264 out_err_free_tfm:
265 	crypto_free_blkcipher(*res);
266 out_err_free_key:
267 	kfree(key.data);
268 	p = ERR_PTR(-EINVAL);
269 out_err:
270 	return p;
271 }
272 
273 static int
274 gss_import_v1_context(const void *p, const void *end, struct krb5_ctx *ctx)
275 {
276 	int tmp;
277 
278 	p = simple_get_bytes(p, end, &ctx->initiate, sizeof(ctx->initiate));
279 	if (IS_ERR(p))
280 		goto out_err;
281 
282 	/* Old format supports only DES!  Any other enctype uses new format */
283 	ctx->enctype = ENCTYPE_DES_CBC_RAW;
284 
285 	ctx->gk5e = get_gss_krb5_enctype(ctx->enctype);
286 	if (ctx->gk5e == NULL) {
287 		p = ERR_PTR(-EINVAL);
288 		goto out_err;
289 	}
290 
291 	/* The downcall format was designed before we completely understood
292 	 * the uses of the context fields; so it includes some stuff we
293 	 * just give some minimal sanity-checking, and some we ignore
294 	 * completely (like the next twenty bytes): */
295 	if (unlikely(p + 20 > end || p + 20 < p)) {
296 		p = ERR_PTR(-EFAULT);
297 		goto out_err;
298 	}
299 	p += 20;
300 	p = simple_get_bytes(p, end, &tmp, sizeof(tmp));
301 	if (IS_ERR(p))
302 		goto out_err;
303 	if (tmp != SGN_ALG_DES_MAC_MD5) {
304 		p = ERR_PTR(-ENOSYS);
305 		goto out_err;
306 	}
307 	p = simple_get_bytes(p, end, &tmp, sizeof(tmp));
308 	if (IS_ERR(p))
309 		goto out_err;
310 	if (tmp != SEAL_ALG_DES) {
311 		p = ERR_PTR(-ENOSYS);
312 		goto out_err;
313 	}
314 	p = simple_get_bytes(p, end, &ctx->endtime, sizeof(ctx->endtime));
315 	if (IS_ERR(p))
316 		goto out_err;
317 	p = simple_get_bytes(p, end, &ctx->seq_send, sizeof(ctx->seq_send));
318 	if (IS_ERR(p))
319 		goto out_err;
320 	p = simple_get_netobj(p, end, &ctx->mech_used);
321 	if (IS_ERR(p))
322 		goto out_err;
323 	p = get_key(p, end, ctx, &ctx->enc);
324 	if (IS_ERR(p))
325 		goto out_err_free_mech;
326 	p = get_key(p, end, ctx, &ctx->seq);
327 	if (IS_ERR(p))
328 		goto out_err_free_key1;
329 	if (p != end) {
330 		p = ERR_PTR(-EFAULT);
331 		goto out_err_free_key2;
332 	}
333 
334 	return 0;
335 
336 out_err_free_key2:
337 	crypto_free_blkcipher(ctx->seq);
338 out_err_free_key1:
339 	crypto_free_blkcipher(ctx->enc);
340 out_err_free_mech:
341 	kfree(ctx->mech_used.data);
342 out_err:
343 	return PTR_ERR(p);
344 }
345 
346 struct crypto_blkcipher *
347 context_v2_alloc_cipher(struct krb5_ctx *ctx, const char *cname, u8 *key)
348 {
349 	struct crypto_blkcipher *cp;
350 
351 	cp = crypto_alloc_blkcipher(cname, 0, CRYPTO_ALG_ASYNC);
352 	if (IS_ERR(cp)) {
353 		dprintk("gss_kerberos_mech: unable to initialize "
354 			"crypto algorithm %s\n", cname);
355 		return NULL;
356 	}
357 	if (crypto_blkcipher_setkey(cp, key, ctx->gk5e->keylength)) {
358 		dprintk("gss_kerberos_mech: error setting key for "
359 			"crypto algorithm %s\n", cname);
360 		crypto_free_blkcipher(cp);
361 		return NULL;
362 	}
363 	return cp;
364 }
365 
366 static inline void
367 set_cdata(u8 cdata[GSS_KRB5_K5CLENGTH], u32 usage, u8 seed)
368 {
369 	cdata[0] = (usage>>24)&0xff;
370 	cdata[1] = (usage>>16)&0xff;
371 	cdata[2] = (usage>>8)&0xff;
372 	cdata[3] = usage&0xff;
373 	cdata[4] = seed;
374 }
375 
376 static int
377 context_derive_keys_des3(struct krb5_ctx *ctx, gfp_t gfp_mask)
378 {
379 	struct xdr_netobj c, keyin, keyout;
380 	u8 cdata[GSS_KRB5_K5CLENGTH];
381 	u32 err;
382 
383 	c.len = GSS_KRB5_K5CLENGTH;
384 	c.data = cdata;
385 
386 	keyin.data = ctx->Ksess;
387 	keyin.len = ctx->gk5e->keylength;
388 	keyout.len = ctx->gk5e->keylength;
389 
390 	/* seq uses the raw key */
391 	ctx->seq = context_v2_alloc_cipher(ctx, ctx->gk5e->encrypt_name,
392 					   ctx->Ksess);
393 	if (ctx->seq == NULL)
394 		goto out_err;
395 
396 	ctx->enc = context_v2_alloc_cipher(ctx, ctx->gk5e->encrypt_name,
397 					   ctx->Ksess);
398 	if (ctx->enc == NULL)
399 		goto out_free_seq;
400 
401 	/* derive cksum */
402 	set_cdata(cdata, KG_USAGE_SIGN, KEY_USAGE_SEED_CHECKSUM);
403 	keyout.data = ctx->cksum;
404 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
405 	if (err) {
406 		dprintk("%s: Error %d deriving cksum key\n",
407 			__func__, err);
408 		goto out_free_enc;
409 	}
410 
411 	return 0;
412 
413 out_free_enc:
414 	crypto_free_blkcipher(ctx->enc);
415 out_free_seq:
416 	crypto_free_blkcipher(ctx->seq);
417 out_err:
418 	return -EINVAL;
419 }
420 
421 /*
422  * Note that RC4 depends on deriving keys using the sequence
423  * number or the checksum of a token.  Therefore, the final keys
424  * cannot be calculated until the token is being constructed!
425  */
426 static int
427 context_derive_keys_rc4(struct krb5_ctx *ctx)
428 {
429 	struct crypto_hash *hmac;
430 	static const char sigkeyconstant[] = "signaturekey";
431 	int slen = strlen(sigkeyconstant) + 1;	/* include null terminator */
432 	struct hash_desc desc;
433 	struct scatterlist sg[1];
434 	int err;
435 
436 	dprintk("RPC:       %s: entered\n", __func__);
437 	/*
438 	 * derive cksum (aka Ksign) key
439 	 */
440 	hmac = crypto_alloc_hash(ctx->gk5e->cksum_name, 0, CRYPTO_ALG_ASYNC);
441 	if (IS_ERR(hmac)) {
442 		dprintk("%s: error %ld allocating hash '%s'\n",
443 			__func__, PTR_ERR(hmac), ctx->gk5e->cksum_name);
444 		err = PTR_ERR(hmac);
445 		goto out_err;
446 	}
447 
448 	err = crypto_hash_setkey(hmac, ctx->Ksess, ctx->gk5e->keylength);
449 	if (err)
450 		goto out_err_free_hmac;
451 
452 	sg_init_table(sg, 1);
453 	sg_set_buf(sg, sigkeyconstant, slen);
454 
455 	desc.tfm = hmac;
456 	desc.flags = 0;
457 
458 	err = crypto_hash_init(&desc);
459 	if (err)
460 		goto out_err_free_hmac;
461 
462 	err = crypto_hash_digest(&desc, sg, slen, ctx->cksum);
463 	if (err)
464 		goto out_err_free_hmac;
465 	/*
466 	 * allocate hash, and blkciphers for data and seqnum encryption
467 	 */
468 	ctx->enc = crypto_alloc_blkcipher(ctx->gk5e->encrypt_name, 0,
469 					  CRYPTO_ALG_ASYNC);
470 	if (IS_ERR(ctx->enc)) {
471 		err = PTR_ERR(ctx->enc);
472 		goto out_err_free_hmac;
473 	}
474 
475 	ctx->seq = crypto_alloc_blkcipher(ctx->gk5e->encrypt_name, 0,
476 					  CRYPTO_ALG_ASYNC);
477 	if (IS_ERR(ctx->seq)) {
478 		crypto_free_blkcipher(ctx->enc);
479 		err = PTR_ERR(ctx->seq);
480 		goto out_err_free_hmac;
481 	}
482 
483 	dprintk("RPC:       %s: returning success\n", __func__);
484 
485 	err = 0;
486 
487 out_err_free_hmac:
488 	crypto_free_hash(hmac);
489 out_err:
490 	dprintk("RPC:       %s: returning %d\n", __func__, err);
491 	return err;
492 }
493 
494 static int
495 context_derive_keys_new(struct krb5_ctx *ctx, gfp_t gfp_mask)
496 {
497 	struct xdr_netobj c, keyin, keyout;
498 	u8 cdata[GSS_KRB5_K5CLENGTH];
499 	u32 err;
500 
501 	c.len = GSS_KRB5_K5CLENGTH;
502 	c.data = cdata;
503 
504 	keyin.data = ctx->Ksess;
505 	keyin.len = ctx->gk5e->keylength;
506 	keyout.len = ctx->gk5e->keylength;
507 
508 	/* initiator seal encryption */
509 	set_cdata(cdata, KG_USAGE_INITIATOR_SEAL, KEY_USAGE_SEED_ENCRYPTION);
510 	keyout.data = ctx->initiator_seal;
511 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
512 	if (err) {
513 		dprintk("%s: Error %d deriving initiator_seal key\n",
514 			__func__, err);
515 		goto out_err;
516 	}
517 	ctx->initiator_enc = context_v2_alloc_cipher(ctx,
518 						     ctx->gk5e->encrypt_name,
519 						     ctx->initiator_seal);
520 	if (ctx->initiator_enc == NULL)
521 		goto out_err;
522 
523 	/* acceptor seal encryption */
524 	set_cdata(cdata, KG_USAGE_ACCEPTOR_SEAL, KEY_USAGE_SEED_ENCRYPTION);
525 	keyout.data = ctx->acceptor_seal;
526 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
527 	if (err) {
528 		dprintk("%s: Error %d deriving acceptor_seal key\n",
529 			__func__, err);
530 		goto out_free_initiator_enc;
531 	}
532 	ctx->acceptor_enc = context_v2_alloc_cipher(ctx,
533 						    ctx->gk5e->encrypt_name,
534 						    ctx->acceptor_seal);
535 	if (ctx->acceptor_enc == NULL)
536 		goto out_free_initiator_enc;
537 
538 	/* initiator sign checksum */
539 	set_cdata(cdata, KG_USAGE_INITIATOR_SIGN, KEY_USAGE_SEED_CHECKSUM);
540 	keyout.data = ctx->initiator_sign;
541 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
542 	if (err) {
543 		dprintk("%s: Error %d deriving initiator_sign key\n",
544 			__func__, err);
545 		goto out_free_acceptor_enc;
546 	}
547 
548 	/* acceptor sign checksum */
549 	set_cdata(cdata, KG_USAGE_ACCEPTOR_SIGN, KEY_USAGE_SEED_CHECKSUM);
550 	keyout.data = ctx->acceptor_sign;
551 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
552 	if (err) {
553 		dprintk("%s: Error %d deriving acceptor_sign key\n",
554 			__func__, err);
555 		goto out_free_acceptor_enc;
556 	}
557 
558 	/* initiator seal integrity */
559 	set_cdata(cdata, KG_USAGE_INITIATOR_SEAL, KEY_USAGE_SEED_INTEGRITY);
560 	keyout.data = ctx->initiator_integ;
561 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
562 	if (err) {
563 		dprintk("%s: Error %d deriving initiator_integ key\n",
564 			__func__, err);
565 		goto out_free_acceptor_enc;
566 	}
567 
568 	/* acceptor seal integrity */
569 	set_cdata(cdata, KG_USAGE_ACCEPTOR_SEAL, KEY_USAGE_SEED_INTEGRITY);
570 	keyout.data = ctx->acceptor_integ;
571 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
572 	if (err) {
573 		dprintk("%s: Error %d deriving acceptor_integ key\n",
574 			__func__, err);
575 		goto out_free_acceptor_enc;
576 	}
577 
578 	switch (ctx->enctype) {
579 	case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
580 	case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
581 		ctx->initiator_enc_aux =
582 			context_v2_alloc_cipher(ctx, "cbc(aes)",
583 						ctx->initiator_seal);
584 		if (ctx->initiator_enc_aux == NULL)
585 			goto out_free_acceptor_enc;
586 		ctx->acceptor_enc_aux =
587 			context_v2_alloc_cipher(ctx, "cbc(aes)",
588 						ctx->acceptor_seal);
589 		if (ctx->acceptor_enc_aux == NULL) {
590 			crypto_free_blkcipher(ctx->initiator_enc_aux);
591 			goto out_free_acceptor_enc;
592 		}
593 	}
594 
595 	return 0;
596 
597 out_free_acceptor_enc:
598 	crypto_free_blkcipher(ctx->acceptor_enc);
599 out_free_initiator_enc:
600 	crypto_free_blkcipher(ctx->initiator_enc);
601 out_err:
602 	return -EINVAL;
603 }
604 
605 static int
606 gss_import_v2_context(const void *p, const void *end, struct krb5_ctx *ctx,
607 		gfp_t gfp_mask)
608 {
609 	int keylen;
610 
611 	p = simple_get_bytes(p, end, &ctx->flags, sizeof(ctx->flags));
612 	if (IS_ERR(p))
613 		goto out_err;
614 	ctx->initiate = ctx->flags & KRB5_CTX_FLAG_INITIATOR;
615 
616 	p = simple_get_bytes(p, end, &ctx->endtime, sizeof(ctx->endtime));
617 	if (IS_ERR(p))
618 		goto out_err;
619 	p = simple_get_bytes(p, end, &ctx->seq_send64, sizeof(ctx->seq_send64));
620 	if (IS_ERR(p))
621 		goto out_err;
622 	/* set seq_send for use by "older" enctypes */
623 	ctx->seq_send = ctx->seq_send64;
624 	if (ctx->seq_send64 != ctx->seq_send) {
625 		dprintk("%s: seq_send64 %lx, seq_send %x overflow?\n", __func__,
626 			(long unsigned)ctx->seq_send64, ctx->seq_send);
627 		p = ERR_PTR(-EINVAL);
628 		goto out_err;
629 	}
630 	p = simple_get_bytes(p, end, &ctx->enctype, sizeof(ctx->enctype));
631 	if (IS_ERR(p))
632 		goto out_err;
633 	/* Map ENCTYPE_DES3_CBC_SHA1 to ENCTYPE_DES3_CBC_RAW */
634 	if (ctx->enctype == ENCTYPE_DES3_CBC_SHA1)
635 		ctx->enctype = ENCTYPE_DES3_CBC_RAW;
636 	ctx->gk5e = get_gss_krb5_enctype(ctx->enctype);
637 	if (ctx->gk5e == NULL) {
638 		dprintk("gss_kerberos_mech: unsupported krb5 enctype %u\n",
639 			ctx->enctype);
640 		p = ERR_PTR(-EINVAL);
641 		goto out_err;
642 	}
643 	keylen = ctx->gk5e->keylength;
644 
645 	p = simple_get_bytes(p, end, ctx->Ksess, keylen);
646 	if (IS_ERR(p))
647 		goto out_err;
648 
649 	if (p != end) {
650 		p = ERR_PTR(-EINVAL);
651 		goto out_err;
652 	}
653 
654 	ctx->mech_used.data = kmemdup(gss_kerberos_mech.gm_oid.data,
655 				      gss_kerberos_mech.gm_oid.len, gfp_mask);
656 	if (unlikely(ctx->mech_used.data == NULL)) {
657 		p = ERR_PTR(-ENOMEM);
658 		goto out_err;
659 	}
660 	ctx->mech_used.len = gss_kerberos_mech.gm_oid.len;
661 
662 	switch (ctx->enctype) {
663 	case ENCTYPE_DES3_CBC_RAW:
664 		return context_derive_keys_des3(ctx, gfp_mask);
665 	case ENCTYPE_ARCFOUR_HMAC:
666 		return context_derive_keys_rc4(ctx);
667 	case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
668 	case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
669 		return context_derive_keys_new(ctx, gfp_mask);
670 	default:
671 		return -EINVAL;
672 	}
673 
674 out_err:
675 	return PTR_ERR(p);
676 }
677 
678 static int
679 gss_import_sec_context_kerberos(const void *p, size_t len,
680 				struct gss_ctx *ctx_id,
681 				gfp_t gfp_mask)
682 {
683 	const void *end = (const void *)((const char *)p + len);
684 	struct  krb5_ctx *ctx;
685 	int ret;
686 
687 	ctx = kzalloc(sizeof(*ctx), gfp_mask);
688 	if (ctx == NULL)
689 		return -ENOMEM;
690 
691 	if (len == 85)
692 		ret = gss_import_v1_context(p, end, ctx);
693 	else
694 		ret = gss_import_v2_context(p, end, ctx, gfp_mask);
695 
696 	if (ret == 0)
697 		ctx_id->internal_ctx_id = ctx;
698 	else
699 		kfree(ctx);
700 
701 	dprintk("RPC:       %s: returning %d\n", __func__, ret);
702 	return ret;
703 }
704 
705 static void
706 gss_delete_sec_context_kerberos(void *internal_ctx) {
707 	struct krb5_ctx *kctx = internal_ctx;
708 
709 	crypto_free_blkcipher(kctx->seq);
710 	crypto_free_blkcipher(kctx->enc);
711 	crypto_free_blkcipher(kctx->acceptor_enc);
712 	crypto_free_blkcipher(kctx->initiator_enc);
713 	crypto_free_blkcipher(kctx->acceptor_enc_aux);
714 	crypto_free_blkcipher(kctx->initiator_enc_aux);
715 	kfree(kctx->mech_used.data);
716 	kfree(kctx);
717 }
718 
719 static const struct gss_api_ops gss_kerberos_ops = {
720 	.gss_import_sec_context	= gss_import_sec_context_kerberos,
721 	.gss_get_mic		= gss_get_mic_kerberos,
722 	.gss_verify_mic		= gss_verify_mic_kerberos,
723 	.gss_wrap		= gss_wrap_kerberos,
724 	.gss_unwrap		= gss_unwrap_kerberos,
725 	.gss_delete_sec_context	= gss_delete_sec_context_kerberos,
726 };
727 
728 static struct pf_desc gss_kerberos_pfs[] = {
729 	[0] = {
730 		.pseudoflavor = RPC_AUTH_GSS_KRB5,
731 		.service = RPC_GSS_SVC_NONE,
732 		.name = "krb5",
733 	},
734 	[1] = {
735 		.pseudoflavor = RPC_AUTH_GSS_KRB5I,
736 		.service = RPC_GSS_SVC_INTEGRITY,
737 		.name = "krb5i",
738 	},
739 	[2] = {
740 		.pseudoflavor = RPC_AUTH_GSS_KRB5P,
741 		.service = RPC_GSS_SVC_PRIVACY,
742 		.name = "krb5p",
743 	},
744 };
745 
746 static struct gss_api_mech gss_kerberos_mech = {
747 	.gm_name	= "krb5",
748 	.gm_owner	= THIS_MODULE,
749 	.gm_oid		= {9, (void *)"\x2a\x86\x48\x86\xf7\x12\x01\x02\x02"},
750 	.gm_ops		= &gss_kerberos_ops,
751 	.gm_pf_num	= ARRAY_SIZE(gss_kerberos_pfs),
752 	.gm_pfs		= gss_kerberos_pfs,
753 	.gm_upcall_enctypes = "enctypes=18,17,16,23,3,1,2 ",
754 };
755 
756 static int __init init_kerberos_module(void)
757 {
758 	int status;
759 
760 	status = gss_mech_register(&gss_kerberos_mech);
761 	if (status)
762 		printk("Failed to register kerberos gss mechanism!\n");
763 	return status;
764 }
765 
766 static void __exit cleanup_kerberos_module(void)
767 {
768 	gss_mech_unregister(&gss_kerberos_mech);
769 }
770 
771 MODULE_LICENSE("GPL");
772 module_init(init_kerberos_module);
773 module_exit(cleanup_kerberos_module);
774