xref: /linux/net/sunrpc/auth_gss/gss_krb5_mech.c (revision cc4589ebfae6f8dbb5cf880a0a67eedab3416492)
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 		goto out_err;
241 	}
242 	p = simple_get_netobj(p, end, &key);
243 	if (IS_ERR(p))
244 		goto out_err;
245 
246 	*res = crypto_alloc_blkcipher(ctx->gk5e->encrypt_name, 0,
247 							CRYPTO_ALG_ASYNC);
248 	if (IS_ERR(*res)) {
249 		printk(KERN_WARNING "gss_kerberos_mech: unable to initialize "
250 			"crypto algorithm %s\n", ctx->gk5e->encrypt_name);
251 		*res = NULL;
252 		goto out_err_free_key;
253 	}
254 	if (crypto_blkcipher_setkey(*res, key.data, key.len)) {
255 		printk(KERN_WARNING "gss_kerberos_mech: error setting key for "
256 			"crypto algorithm %s\n", ctx->gk5e->encrypt_name);
257 		goto out_err_free_tfm;
258 	}
259 
260 	kfree(key.data);
261 	return p;
262 
263 out_err_free_tfm:
264 	crypto_free_blkcipher(*res);
265 out_err_free_key:
266 	kfree(key.data);
267 	p = ERR_PTR(-EINVAL);
268 out_err:
269 	return p;
270 }
271 
272 static int
273 gss_import_v1_context(const void *p, const void *end, struct krb5_ctx *ctx)
274 {
275 	int tmp;
276 
277 	p = simple_get_bytes(p, end, &ctx->initiate, sizeof(ctx->initiate));
278 	if (IS_ERR(p))
279 		goto out_err;
280 
281 	/* Old format supports only DES!  Any other enctype uses new format */
282 	ctx->enctype = ENCTYPE_DES_CBC_RAW;
283 
284 	ctx->gk5e = get_gss_krb5_enctype(ctx->enctype);
285 	if (ctx->gk5e == NULL)
286 		goto out_err;
287 
288 	/* The downcall format was designed before we completely understood
289 	 * the uses of the context fields; so it includes some stuff we
290 	 * just give some minimal sanity-checking, and some we ignore
291 	 * completely (like the next twenty bytes): */
292 	if (unlikely(p + 20 > end || p + 20 < p))
293 		goto out_err;
294 	p += 20;
295 	p = simple_get_bytes(p, end, &tmp, sizeof(tmp));
296 	if (IS_ERR(p))
297 		goto out_err;
298 	if (tmp != SGN_ALG_DES_MAC_MD5) {
299 		p = ERR_PTR(-ENOSYS);
300 		goto out_err;
301 	}
302 	p = simple_get_bytes(p, end, &tmp, sizeof(tmp));
303 	if (IS_ERR(p))
304 		goto out_err;
305 	if (tmp != SEAL_ALG_DES) {
306 		p = ERR_PTR(-ENOSYS);
307 		goto out_err;
308 	}
309 	p = simple_get_bytes(p, end, &ctx->endtime, sizeof(ctx->endtime));
310 	if (IS_ERR(p))
311 		goto out_err;
312 	p = simple_get_bytes(p, end, &ctx->seq_send, sizeof(ctx->seq_send));
313 	if (IS_ERR(p))
314 		goto out_err;
315 	p = simple_get_netobj(p, end, &ctx->mech_used);
316 	if (IS_ERR(p))
317 		goto out_err;
318 	p = get_key(p, end, ctx, &ctx->enc);
319 	if (IS_ERR(p))
320 		goto out_err_free_mech;
321 	p = get_key(p, end, ctx, &ctx->seq);
322 	if (IS_ERR(p))
323 		goto out_err_free_key1;
324 	if (p != end) {
325 		p = ERR_PTR(-EFAULT);
326 		goto out_err_free_key2;
327 	}
328 
329 	return 0;
330 
331 out_err_free_key2:
332 	crypto_free_blkcipher(ctx->seq);
333 out_err_free_key1:
334 	crypto_free_blkcipher(ctx->enc);
335 out_err_free_mech:
336 	kfree(ctx->mech_used.data);
337 out_err:
338 	return PTR_ERR(p);
339 }
340 
341 struct crypto_blkcipher *
342 context_v2_alloc_cipher(struct krb5_ctx *ctx, const char *cname, u8 *key)
343 {
344 	struct crypto_blkcipher *cp;
345 
346 	cp = crypto_alloc_blkcipher(cname, 0, CRYPTO_ALG_ASYNC);
347 	if (IS_ERR(cp)) {
348 		dprintk("gss_kerberos_mech: unable to initialize "
349 			"crypto algorithm %s\n", cname);
350 		return NULL;
351 	}
352 	if (crypto_blkcipher_setkey(cp, key, ctx->gk5e->keylength)) {
353 		dprintk("gss_kerberos_mech: error setting key for "
354 			"crypto algorithm %s\n", cname);
355 		crypto_free_blkcipher(cp);
356 		return NULL;
357 	}
358 	return cp;
359 }
360 
361 static inline void
362 set_cdata(u8 cdata[GSS_KRB5_K5CLENGTH], u32 usage, u8 seed)
363 {
364 	cdata[0] = (usage>>24)&0xff;
365 	cdata[1] = (usage>>16)&0xff;
366 	cdata[2] = (usage>>8)&0xff;
367 	cdata[3] = usage&0xff;
368 	cdata[4] = seed;
369 }
370 
371 static int
372 context_derive_keys_des3(struct krb5_ctx *ctx, gfp_t gfp_mask)
373 {
374 	struct xdr_netobj c, keyin, keyout;
375 	u8 cdata[GSS_KRB5_K5CLENGTH];
376 	u32 err;
377 
378 	c.len = GSS_KRB5_K5CLENGTH;
379 	c.data = cdata;
380 
381 	keyin.data = ctx->Ksess;
382 	keyin.len = ctx->gk5e->keylength;
383 	keyout.len = ctx->gk5e->keylength;
384 
385 	/* seq uses the raw key */
386 	ctx->seq = context_v2_alloc_cipher(ctx, ctx->gk5e->encrypt_name,
387 					   ctx->Ksess);
388 	if (ctx->seq == NULL)
389 		goto out_err;
390 
391 	ctx->enc = context_v2_alloc_cipher(ctx, ctx->gk5e->encrypt_name,
392 					   ctx->Ksess);
393 	if (ctx->enc == NULL)
394 		goto out_free_seq;
395 
396 	/* derive cksum */
397 	set_cdata(cdata, KG_USAGE_SIGN, KEY_USAGE_SEED_CHECKSUM);
398 	keyout.data = ctx->cksum;
399 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
400 	if (err) {
401 		dprintk("%s: Error %d deriving cksum key\n",
402 			__func__, err);
403 		goto out_free_enc;
404 	}
405 
406 	return 0;
407 
408 out_free_enc:
409 	crypto_free_blkcipher(ctx->enc);
410 out_free_seq:
411 	crypto_free_blkcipher(ctx->seq);
412 out_err:
413 	return -EINVAL;
414 }
415 
416 /*
417  * Note that RC4 depends on deriving keys using the sequence
418  * number or the checksum of a token.  Therefore, the final keys
419  * cannot be calculated until the token is being constructed!
420  */
421 static int
422 context_derive_keys_rc4(struct krb5_ctx *ctx)
423 {
424 	struct crypto_hash *hmac;
425 	char sigkeyconstant[] = "signaturekey";
426 	int slen = strlen(sigkeyconstant) + 1;	/* include null terminator */
427 	struct hash_desc desc;
428 	struct scatterlist sg[1];
429 	int err;
430 
431 	dprintk("RPC:       %s: entered\n", __func__);
432 	/*
433 	 * derive cksum (aka Ksign) key
434 	 */
435 	hmac = crypto_alloc_hash(ctx->gk5e->cksum_name, 0, CRYPTO_ALG_ASYNC);
436 	if (IS_ERR(hmac)) {
437 		dprintk("%s: error %ld allocating hash '%s'\n",
438 			__func__, PTR_ERR(hmac), ctx->gk5e->cksum_name);
439 		err = PTR_ERR(hmac);
440 		goto out_err;
441 	}
442 
443 	err = crypto_hash_setkey(hmac, ctx->Ksess, ctx->gk5e->keylength);
444 	if (err)
445 		goto out_err_free_hmac;
446 
447 	sg_init_table(sg, 1);
448 	sg_set_buf(sg, sigkeyconstant, slen);
449 
450 	desc.tfm = hmac;
451 	desc.flags = 0;
452 
453 	err = crypto_hash_init(&desc);
454 	if (err)
455 		goto out_err_free_hmac;
456 
457 	err = crypto_hash_digest(&desc, sg, slen, ctx->cksum);
458 	if (err)
459 		goto out_err_free_hmac;
460 	/*
461 	 * allocate hash, and blkciphers for data and seqnum encryption
462 	 */
463 	ctx->enc = crypto_alloc_blkcipher(ctx->gk5e->encrypt_name, 0,
464 					  CRYPTO_ALG_ASYNC);
465 	if (IS_ERR(ctx->enc)) {
466 		err = PTR_ERR(ctx->enc);
467 		goto out_err_free_hmac;
468 	}
469 
470 	ctx->seq = crypto_alloc_blkcipher(ctx->gk5e->encrypt_name, 0,
471 					  CRYPTO_ALG_ASYNC);
472 	if (IS_ERR(ctx->seq)) {
473 		crypto_free_blkcipher(ctx->enc);
474 		err = PTR_ERR(ctx->seq);
475 		goto out_err_free_hmac;
476 	}
477 
478 	dprintk("RPC:       %s: returning success\n", __func__);
479 
480 	err = 0;
481 
482 out_err_free_hmac:
483 	crypto_free_hash(hmac);
484 out_err:
485 	dprintk("RPC:       %s: returning %d\n", __func__, err);
486 	return err;
487 }
488 
489 static int
490 context_derive_keys_new(struct krb5_ctx *ctx, gfp_t gfp_mask)
491 {
492 	struct xdr_netobj c, keyin, keyout;
493 	u8 cdata[GSS_KRB5_K5CLENGTH];
494 	u32 err;
495 
496 	c.len = GSS_KRB5_K5CLENGTH;
497 	c.data = cdata;
498 
499 	keyin.data = ctx->Ksess;
500 	keyin.len = ctx->gk5e->keylength;
501 	keyout.len = ctx->gk5e->keylength;
502 
503 	/* initiator seal encryption */
504 	set_cdata(cdata, KG_USAGE_INITIATOR_SEAL, KEY_USAGE_SEED_ENCRYPTION);
505 	keyout.data = ctx->initiator_seal;
506 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
507 	if (err) {
508 		dprintk("%s: Error %d deriving initiator_seal key\n",
509 			__func__, err);
510 		goto out_err;
511 	}
512 	ctx->initiator_enc = context_v2_alloc_cipher(ctx,
513 						     ctx->gk5e->encrypt_name,
514 						     ctx->initiator_seal);
515 	if (ctx->initiator_enc == NULL)
516 		goto out_err;
517 
518 	/* acceptor seal encryption */
519 	set_cdata(cdata, KG_USAGE_ACCEPTOR_SEAL, KEY_USAGE_SEED_ENCRYPTION);
520 	keyout.data = ctx->acceptor_seal;
521 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
522 	if (err) {
523 		dprintk("%s: Error %d deriving acceptor_seal key\n",
524 			__func__, err);
525 		goto out_free_initiator_enc;
526 	}
527 	ctx->acceptor_enc = context_v2_alloc_cipher(ctx,
528 						    ctx->gk5e->encrypt_name,
529 						    ctx->acceptor_seal);
530 	if (ctx->acceptor_enc == NULL)
531 		goto out_free_initiator_enc;
532 
533 	/* initiator sign checksum */
534 	set_cdata(cdata, KG_USAGE_INITIATOR_SIGN, KEY_USAGE_SEED_CHECKSUM);
535 	keyout.data = ctx->initiator_sign;
536 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
537 	if (err) {
538 		dprintk("%s: Error %d deriving initiator_sign key\n",
539 			__func__, err);
540 		goto out_free_acceptor_enc;
541 	}
542 
543 	/* acceptor sign checksum */
544 	set_cdata(cdata, KG_USAGE_ACCEPTOR_SIGN, KEY_USAGE_SEED_CHECKSUM);
545 	keyout.data = ctx->acceptor_sign;
546 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
547 	if (err) {
548 		dprintk("%s: Error %d deriving acceptor_sign key\n",
549 			__func__, err);
550 		goto out_free_acceptor_enc;
551 	}
552 
553 	/* initiator seal integrity */
554 	set_cdata(cdata, KG_USAGE_INITIATOR_SEAL, KEY_USAGE_SEED_INTEGRITY);
555 	keyout.data = ctx->initiator_integ;
556 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
557 	if (err) {
558 		dprintk("%s: Error %d deriving initiator_integ key\n",
559 			__func__, err);
560 		goto out_free_acceptor_enc;
561 	}
562 
563 	/* acceptor seal integrity */
564 	set_cdata(cdata, KG_USAGE_ACCEPTOR_SEAL, KEY_USAGE_SEED_INTEGRITY);
565 	keyout.data = ctx->acceptor_integ;
566 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
567 	if (err) {
568 		dprintk("%s: Error %d deriving acceptor_integ key\n",
569 			__func__, err);
570 		goto out_free_acceptor_enc;
571 	}
572 
573 	switch (ctx->enctype) {
574 	case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
575 	case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
576 		ctx->initiator_enc_aux =
577 			context_v2_alloc_cipher(ctx, "cbc(aes)",
578 						ctx->initiator_seal);
579 		if (ctx->initiator_enc_aux == NULL)
580 			goto out_free_acceptor_enc;
581 		ctx->acceptor_enc_aux =
582 			context_v2_alloc_cipher(ctx, "cbc(aes)",
583 						ctx->acceptor_seal);
584 		if (ctx->acceptor_enc_aux == NULL) {
585 			crypto_free_blkcipher(ctx->initiator_enc_aux);
586 			goto out_free_acceptor_enc;
587 		}
588 	}
589 
590 	return 0;
591 
592 out_free_acceptor_enc:
593 	crypto_free_blkcipher(ctx->acceptor_enc);
594 out_free_initiator_enc:
595 	crypto_free_blkcipher(ctx->initiator_enc);
596 out_err:
597 	return -EINVAL;
598 }
599 
600 static int
601 gss_import_v2_context(const void *p, const void *end, struct krb5_ctx *ctx,
602 		gfp_t gfp_mask)
603 {
604 	int keylen;
605 
606 	p = simple_get_bytes(p, end, &ctx->flags, sizeof(ctx->flags));
607 	if (IS_ERR(p))
608 		goto out_err;
609 	ctx->initiate = ctx->flags & KRB5_CTX_FLAG_INITIATOR;
610 
611 	p = simple_get_bytes(p, end, &ctx->endtime, sizeof(ctx->endtime));
612 	if (IS_ERR(p))
613 		goto out_err;
614 	p = simple_get_bytes(p, end, &ctx->seq_send64, sizeof(ctx->seq_send64));
615 	if (IS_ERR(p))
616 		goto out_err;
617 	/* set seq_send for use by "older" enctypes */
618 	ctx->seq_send = ctx->seq_send64;
619 	if (ctx->seq_send64 != ctx->seq_send) {
620 		dprintk("%s: seq_send64 %lx, seq_send %x overflow?\n", __func__,
621 			(long unsigned)ctx->seq_send64, ctx->seq_send);
622 		goto out_err;
623 	}
624 	p = simple_get_bytes(p, end, &ctx->enctype, sizeof(ctx->enctype));
625 	if (IS_ERR(p))
626 		goto out_err;
627 	/* Map ENCTYPE_DES3_CBC_SHA1 to ENCTYPE_DES3_CBC_RAW */
628 	if (ctx->enctype == ENCTYPE_DES3_CBC_SHA1)
629 		ctx->enctype = ENCTYPE_DES3_CBC_RAW;
630 	ctx->gk5e = get_gss_krb5_enctype(ctx->enctype);
631 	if (ctx->gk5e == NULL) {
632 		dprintk("gss_kerberos_mech: unsupported krb5 enctype %u\n",
633 			ctx->enctype);
634 		p = ERR_PTR(-EINVAL);
635 		goto out_err;
636 	}
637 	keylen = ctx->gk5e->keylength;
638 
639 	p = simple_get_bytes(p, end, ctx->Ksess, keylen);
640 	if (IS_ERR(p))
641 		goto out_err;
642 
643 	if (p != end) {
644 		p = ERR_PTR(-EINVAL);
645 		goto out_err;
646 	}
647 
648 	ctx->mech_used.data = kmemdup(gss_kerberos_mech.gm_oid.data,
649 				      gss_kerberos_mech.gm_oid.len, gfp_mask);
650 	if (unlikely(ctx->mech_used.data == NULL)) {
651 		p = ERR_PTR(-ENOMEM);
652 		goto out_err;
653 	}
654 	ctx->mech_used.len = gss_kerberos_mech.gm_oid.len;
655 
656 	switch (ctx->enctype) {
657 	case ENCTYPE_DES3_CBC_RAW:
658 		return context_derive_keys_des3(ctx, gfp_mask);
659 	case ENCTYPE_ARCFOUR_HMAC:
660 		return context_derive_keys_rc4(ctx);
661 	case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
662 	case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
663 		return context_derive_keys_new(ctx, gfp_mask);
664 	default:
665 		return -EINVAL;
666 	}
667 
668 out_err:
669 	return PTR_ERR(p);
670 }
671 
672 static int
673 gss_import_sec_context_kerberos(const void *p, size_t len,
674 				struct gss_ctx *ctx_id,
675 				gfp_t gfp_mask)
676 {
677 	const void *end = (const void *)((const char *)p + len);
678 	struct  krb5_ctx *ctx;
679 	int ret;
680 
681 	ctx = kzalloc(sizeof(*ctx), gfp_mask);
682 	if (ctx == NULL)
683 		return -ENOMEM;
684 
685 	if (len == 85)
686 		ret = gss_import_v1_context(p, end, ctx);
687 	else
688 		ret = gss_import_v2_context(p, end, ctx, gfp_mask);
689 
690 	if (ret == 0)
691 		ctx_id->internal_ctx_id = ctx;
692 	else
693 		kfree(ctx);
694 
695 	dprintk("RPC:       %s: returning %d\n", __func__, ret);
696 	return ret;
697 }
698 
699 static void
700 gss_delete_sec_context_kerberos(void *internal_ctx) {
701 	struct krb5_ctx *kctx = internal_ctx;
702 
703 	crypto_free_blkcipher(kctx->seq);
704 	crypto_free_blkcipher(kctx->enc);
705 	crypto_free_blkcipher(kctx->acceptor_enc);
706 	crypto_free_blkcipher(kctx->initiator_enc);
707 	crypto_free_blkcipher(kctx->acceptor_enc_aux);
708 	crypto_free_blkcipher(kctx->initiator_enc_aux);
709 	kfree(kctx->mech_used.data);
710 	kfree(kctx);
711 }
712 
713 static const struct gss_api_ops gss_kerberos_ops = {
714 	.gss_import_sec_context	= gss_import_sec_context_kerberos,
715 	.gss_get_mic		= gss_get_mic_kerberos,
716 	.gss_verify_mic		= gss_verify_mic_kerberos,
717 	.gss_wrap		= gss_wrap_kerberos,
718 	.gss_unwrap		= gss_unwrap_kerberos,
719 	.gss_delete_sec_context	= gss_delete_sec_context_kerberos,
720 };
721 
722 static struct pf_desc gss_kerberos_pfs[] = {
723 	[0] = {
724 		.pseudoflavor = RPC_AUTH_GSS_KRB5,
725 		.service = RPC_GSS_SVC_NONE,
726 		.name = "krb5",
727 	},
728 	[1] = {
729 		.pseudoflavor = RPC_AUTH_GSS_KRB5I,
730 		.service = RPC_GSS_SVC_INTEGRITY,
731 		.name = "krb5i",
732 	},
733 	[2] = {
734 		.pseudoflavor = RPC_AUTH_GSS_KRB5P,
735 		.service = RPC_GSS_SVC_PRIVACY,
736 		.name = "krb5p",
737 	},
738 };
739 
740 static struct gss_api_mech gss_kerberos_mech = {
741 	.gm_name	= "krb5",
742 	.gm_owner	= THIS_MODULE,
743 	.gm_oid		= {9, (void *)"\x2a\x86\x48\x86\xf7\x12\x01\x02\x02"},
744 	.gm_ops		= &gss_kerberos_ops,
745 	.gm_pf_num	= ARRAY_SIZE(gss_kerberos_pfs),
746 	.gm_pfs		= gss_kerberos_pfs,
747 	.gm_upcall_enctypes = "enctypes=18,17,16,23,3,1,2 ",
748 };
749 
750 static int __init init_kerberos_module(void)
751 {
752 	int status;
753 
754 	status = gss_mech_register(&gss_kerberos_mech);
755 	if (status)
756 		printk("Failed to register kerberos gss mechanism!\n");
757 	return status;
758 }
759 
760 static void __exit cleanup_kerberos_module(void)
761 {
762 	gss_mech_unregister(&gss_kerberos_mech);
763 }
764 
765 MODULE_LICENSE("GPL");
766 module_init(init_kerberos_module);
767 module_exit(cleanup_kerberos_module);
768