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),
455 		       GFP_KERNEL);
456 	if (!desc) {
457 		dprintk("%s: failed to allocate hash descriptor for '%s'\n",
458 			__func__, ctx->gk5e->cksum_name);
459 		err = -ENOMEM;
460 		goto out_err_free_hmac;
461 	}
462 
463 	desc->tfm = hmac;
464 	desc->flags = 0;
465 
466 	err = crypto_shash_digest(desc, sigkeyconstant, slen, ctx->cksum);
467 	kzfree(desc);
468 	if (err)
469 		goto out_err_free_hmac;
470 	/*
471 	 * allocate hash, and skciphers for data and seqnum encryption
472 	 */
473 	ctx->enc = crypto_alloc_skcipher(ctx->gk5e->encrypt_name, 0,
474 					 CRYPTO_ALG_ASYNC);
475 	if (IS_ERR(ctx->enc)) {
476 		err = PTR_ERR(ctx->enc);
477 		goto out_err_free_hmac;
478 	}
479 
480 	ctx->seq = crypto_alloc_skcipher(ctx->gk5e->encrypt_name, 0,
481 					 CRYPTO_ALG_ASYNC);
482 	if (IS_ERR(ctx->seq)) {
483 		crypto_free_skcipher(ctx->enc);
484 		err = PTR_ERR(ctx->seq);
485 		goto out_err_free_hmac;
486 	}
487 
488 	dprintk("RPC:       %s: returning success\n", __func__);
489 
490 	err = 0;
491 
492 out_err_free_hmac:
493 	crypto_free_shash(hmac);
494 out_err:
495 	dprintk("RPC:       %s: returning %d\n", __func__, err);
496 	return err;
497 }
498 
499 static int
500 context_derive_keys_new(struct krb5_ctx *ctx, gfp_t gfp_mask)
501 {
502 	struct xdr_netobj c, keyin, keyout;
503 	u8 cdata[GSS_KRB5_K5CLENGTH];
504 	u32 err;
505 
506 	c.len = GSS_KRB5_K5CLENGTH;
507 	c.data = cdata;
508 
509 	keyin.data = ctx->Ksess;
510 	keyin.len = ctx->gk5e->keylength;
511 	keyout.len = ctx->gk5e->keylength;
512 
513 	/* initiator seal encryption */
514 	set_cdata(cdata, KG_USAGE_INITIATOR_SEAL, KEY_USAGE_SEED_ENCRYPTION);
515 	keyout.data = ctx->initiator_seal;
516 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
517 	if (err) {
518 		dprintk("%s: Error %d deriving initiator_seal key\n",
519 			__func__, err);
520 		goto out_err;
521 	}
522 	ctx->initiator_enc = context_v2_alloc_cipher(ctx,
523 						     ctx->gk5e->encrypt_name,
524 						     ctx->initiator_seal);
525 	if (ctx->initiator_enc == NULL)
526 		goto out_err;
527 
528 	/* acceptor seal encryption */
529 	set_cdata(cdata, KG_USAGE_ACCEPTOR_SEAL, KEY_USAGE_SEED_ENCRYPTION);
530 	keyout.data = ctx->acceptor_seal;
531 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
532 	if (err) {
533 		dprintk("%s: Error %d deriving acceptor_seal key\n",
534 			__func__, err);
535 		goto out_free_initiator_enc;
536 	}
537 	ctx->acceptor_enc = context_v2_alloc_cipher(ctx,
538 						    ctx->gk5e->encrypt_name,
539 						    ctx->acceptor_seal);
540 	if (ctx->acceptor_enc == NULL)
541 		goto out_free_initiator_enc;
542 
543 	/* initiator sign checksum */
544 	set_cdata(cdata, KG_USAGE_INITIATOR_SIGN, KEY_USAGE_SEED_CHECKSUM);
545 	keyout.data = ctx->initiator_sign;
546 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
547 	if (err) {
548 		dprintk("%s: Error %d deriving initiator_sign key\n",
549 			__func__, err);
550 		goto out_free_acceptor_enc;
551 	}
552 
553 	/* acceptor sign checksum */
554 	set_cdata(cdata, KG_USAGE_ACCEPTOR_SIGN, KEY_USAGE_SEED_CHECKSUM);
555 	keyout.data = ctx->acceptor_sign;
556 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
557 	if (err) {
558 		dprintk("%s: Error %d deriving acceptor_sign key\n",
559 			__func__, err);
560 		goto out_free_acceptor_enc;
561 	}
562 
563 	/* initiator seal integrity */
564 	set_cdata(cdata, KG_USAGE_INITIATOR_SEAL, KEY_USAGE_SEED_INTEGRITY);
565 	keyout.data = ctx->initiator_integ;
566 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
567 	if (err) {
568 		dprintk("%s: Error %d deriving initiator_integ key\n",
569 			__func__, err);
570 		goto out_free_acceptor_enc;
571 	}
572 
573 	/* acceptor seal integrity */
574 	set_cdata(cdata, KG_USAGE_ACCEPTOR_SEAL, KEY_USAGE_SEED_INTEGRITY);
575 	keyout.data = ctx->acceptor_integ;
576 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
577 	if (err) {
578 		dprintk("%s: Error %d deriving acceptor_integ key\n",
579 			__func__, err);
580 		goto out_free_acceptor_enc;
581 	}
582 
583 	switch (ctx->enctype) {
584 	case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
585 	case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
586 		ctx->initiator_enc_aux =
587 			context_v2_alloc_cipher(ctx, "cbc(aes)",
588 						ctx->initiator_seal);
589 		if (ctx->initiator_enc_aux == NULL)
590 			goto out_free_acceptor_enc;
591 		ctx->acceptor_enc_aux =
592 			context_v2_alloc_cipher(ctx, "cbc(aes)",
593 						ctx->acceptor_seal);
594 		if (ctx->acceptor_enc_aux == NULL) {
595 			crypto_free_skcipher(ctx->initiator_enc_aux);
596 			goto out_free_acceptor_enc;
597 		}
598 	}
599 
600 	return 0;
601 
602 out_free_acceptor_enc:
603 	crypto_free_skcipher(ctx->acceptor_enc);
604 out_free_initiator_enc:
605 	crypto_free_skcipher(ctx->initiator_enc);
606 out_err:
607 	return -EINVAL;
608 }
609 
610 static int
611 gss_import_v2_context(const void *p, const void *end, struct krb5_ctx *ctx,
612 		gfp_t gfp_mask)
613 {
614 	int keylen;
615 
616 	p = simple_get_bytes(p, end, &ctx->flags, sizeof(ctx->flags));
617 	if (IS_ERR(p))
618 		goto out_err;
619 	ctx->initiate = ctx->flags & KRB5_CTX_FLAG_INITIATOR;
620 
621 	p = simple_get_bytes(p, end, &ctx->endtime, sizeof(ctx->endtime));
622 	if (IS_ERR(p))
623 		goto out_err;
624 	p = simple_get_bytes(p, end, &ctx->seq_send64, sizeof(ctx->seq_send64));
625 	if (IS_ERR(p))
626 		goto out_err;
627 	/* set seq_send for use by "older" enctypes */
628 	ctx->seq_send = ctx->seq_send64;
629 	if (ctx->seq_send64 != ctx->seq_send) {
630 		dprintk("%s: seq_send64 %lx, seq_send %x overflow?\n", __func__,
631 			(unsigned long)ctx->seq_send64, ctx->seq_send);
632 		p = ERR_PTR(-EINVAL);
633 		goto out_err;
634 	}
635 	p = simple_get_bytes(p, end, &ctx->enctype, sizeof(ctx->enctype));
636 	if (IS_ERR(p))
637 		goto out_err;
638 	/* Map ENCTYPE_DES3_CBC_SHA1 to ENCTYPE_DES3_CBC_RAW */
639 	if (ctx->enctype == ENCTYPE_DES3_CBC_SHA1)
640 		ctx->enctype = ENCTYPE_DES3_CBC_RAW;
641 	ctx->gk5e = get_gss_krb5_enctype(ctx->enctype);
642 	if (ctx->gk5e == NULL) {
643 		dprintk("gss_kerberos_mech: unsupported krb5 enctype %u\n",
644 			ctx->enctype);
645 		p = ERR_PTR(-EINVAL);
646 		goto out_err;
647 	}
648 	keylen = ctx->gk5e->keylength;
649 
650 	p = simple_get_bytes(p, end, ctx->Ksess, keylen);
651 	if (IS_ERR(p))
652 		goto out_err;
653 
654 	if (p != end) {
655 		p = ERR_PTR(-EINVAL);
656 		goto out_err;
657 	}
658 
659 	ctx->mech_used.data = kmemdup(gss_kerberos_mech.gm_oid.data,
660 				      gss_kerberos_mech.gm_oid.len, gfp_mask);
661 	if (unlikely(ctx->mech_used.data == NULL)) {
662 		p = ERR_PTR(-ENOMEM);
663 		goto out_err;
664 	}
665 	ctx->mech_used.len = gss_kerberos_mech.gm_oid.len;
666 
667 	switch (ctx->enctype) {
668 	case ENCTYPE_DES3_CBC_RAW:
669 		return context_derive_keys_des3(ctx, gfp_mask);
670 	case ENCTYPE_ARCFOUR_HMAC:
671 		return context_derive_keys_rc4(ctx);
672 	case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
673 	case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
674 		return context_derive_keys_new(ctx, gfp_mask);
675 	default:
676 		return -EINVAL;
677 	}
678 
679 out_err:
680 	return PTR_ERR(p);
681 }
682 
683 static int
684 gss_import_sec_context_kerberos(const void *p, size_t len,
685 				struct gss_ctx *ctx_id,
686 				time_t *endtime,
687 				gfp_t gfp_mask)
688 {
689 	const void *end = (const void *)((const char *)p + len);
690 	struct  krb5_ctx *ctx;
691 	int ret;
692 
693 	ctx = kzalloc(sizeof(*ctx), gfp_mask);
694 	if (ctx == NULL)
695 		return -ENOMEM;
696 
697 	if (len == 85)
698 		ret = gss_import_v1_context(p, end, ctx);
699 	else
700 		ret = gss_import_v2_context(p, end, ctx, gfp_mask);
701 
702 	if (ret == 0) {
703 		ctx_id->internal_ctx_id = ctx;
704 		if (endtime)
705 			*endtime = ctx->endtime;
706 	} else
707 		kfree(ctx);
708 
709 	dprintk("RPC:       %s: returning %d\n", __func__, ret);
710 	return ret;
711 }
712 
713 static void
714 gss_delete_sec_context_kerberos(void *internal_ctx) {
715 	struct krb5_ctx *kctx = internal_ctx;
716 
717 	crypto_free_skcipher(kctx->seq);
718 	crypto_free_skcipher(kctx->enc);
719 	crypto_free_skcipher(kctx->acceptor_enc);
720 	crypto_free_skcipher(kctx->initiator_enc);
721 	crypto_free_skcipher(kctx->acceptor_enc_aux);
722 	crypto_free_skcipher(kctx->initiator_enc_aux);
723 	kfree(kctx->mech_used.data);
724 	kfree(kctx);
725 }
726 
727 static const struct gss_api_ops gss_kerberos_ops = {
728 	.gss_import_sec_context	= gss_import_sec_context_kerberos,
729 	.gss_get_mic		= gss_get_mic_kerberos,
730 	.gss_verify_mic		= gss_verify_mic_kerberos,
731 	.gss_wrap		= gss_wrap_kerberos,
732 	.gss_unwrap		= gss_unwrap_kerberos,
733 	.gss_delete_sec_context	= gss_delete_sec_context_kerberos,
734 };
735 
736 static struct pf_desc gss_kerberos_pfs[] = {
737 	[0] = {
738 		.pseudoflavor = RPC_AUTH_GSS_KRB5,
739 		.qop = GSS_C_QOP_DEFAULT,
740 		.service = RPC_GSS_SVC_NONE,
741 		.name = "krb5",
742 	},
743 	[1] = {
744 		.pseudoflavor = RPC_AUTH_GSS_KRB5I,
745 		.qop = GSS_C_QOP_DEFAULT,
746 		.service = RPC_GSS_SVC_INTEGRITY,
747 		.name = "krb5i",
748 		.datatouch = true,
749 	},
750 	[2] = {
751 		.pseudoflavor = RPC_AUTH_GSS_KRB5P,
752 		.qop = GSS_C_QOP_DEFAULT,
753 		.service = RPC_GSS_SVC_PRIVACY,
754 		.name = "krb5p",
755 		.datatouch = true,
756 	},
757 };
758 
759 MODULE_ALIAS("rpc-auth-gss-krb5");
760 MODULE_ALIAS("rpc-auth-gss-krb5i");
761 MODULE_ALIAS("rpc-auth-gss-krb5p");
762 MODULE_ALIAS("rpc-auth-gss-390003");
763 MODULE_ALIAS("rpc-auth-gss-390004");
764 MODULE_ALIAS("rpc-auth-gss-390005");
765 MODULE_ALIAS("rpc-auth-gss-1.2.840.113554.1.2.2");
766 
767 static struct gss_api_mech gss_kerberos_mech = {
768 	.gm_name	= "krb5",
769 	.gm_owner	= THIS_MODULE,
770 	.gm_oid		= { 9, "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02" },
771 	.gm_ops		= &gss_kerberos_ops,
772 	.gm_pf_num	= ARRAY_SIZE(gss_kerberos_pfs),
773 	.gm_pfs		= gss_kerberos_pfs,
774 	.gm_upcall_enctypes = KRB5_SUPPORTED_ENCTYPES,
775 };
776 
777 static int __init init_kerberos_module(void)
778 {
779 	int status;
780 
781 	status = gss_mech_register(&gss_kerberos_mech);
782 	if (status)
783 		printk("Failed to register kerberos gss mechanism!\n");
784 	return status;
785 }
786 
787 static void __exit cleanup_kerberos_module(void)
788 {
789 	gss_mech_unregister(&gss_kerberos_mech);
790 }
791 
792 MODULE_LICENSE("GPL");
793 module_init(init_kerberos_module);
794 module_exit(cleanup_kerberos_module);
795