xref: /linux/net/sunrpc/auth_gss/gss_krb5_mech.c (revision af873fcecef567abf8a3468b06dd4e4aab46da6d)
1 // SPDX-License-Identifier: BSD-3-Clause
2 /*
3  *  linux/net/sunrpc/gss_krb5_mech.c
4  *
5  *  Copyright (c) 2001-2008 The Regents of the University of Michigan.
6  *  All rights reserved.
7  *
8  *  Andy Adamson <andros@umich.edu>
9  *  J. Bruce Fields <bfields@umich.edu>
10  */
11 
12 #include <crypto/hash.h>
13 #include <crypto/skcipher.h>
14 #include <linux/err.h>
15 #include <linux/module.h>
16 #include <linux/init.h>
17 #include <linux/types.h>
18 #include <linux/slab.h>
19 #include <linux/sunrpc/auth.h>
20 #include <linux/sunrpc/gss_krb5.h>
21 #include <linux/sunrpc/xdr.h>
22 #include <linux/sunrpc/gss_krb5_enctypes.h>
23 
24 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
25 # define RPCDBG_FACILITY	RPCDBG_AUTH
26 #endif
27 
28 static struct gss_api_mech gss_kerberos_mech;	/* forward declaration */
29 
30 static const struct gss_krb5_enctype supported_gss_krb5_enctypes[] = {
31 #ifndef CONFIG_SUNRPC_DISABLE_INSECURE_ENCTYPES
32 	/*
33 	 * DES (All DES enctypes are mapped to the same gss functionality)
34 	 */
35 	{
36 	  .etype = ENCTYPE_DES_CBC_RAW,
37 	  .ctype = CKSUMTYPE_RSA_MD5,
38 	  .name = "des-cbc-crc",
39 	  .encrypt_name = "cbc(des)",
40 	  .cksum_name = "md5",
41 	  .encrypt = krb5_encrypt,
42 	  .decrypt = krb5_decrypt,
43 	  .mk_key = NULL,
44 	  .signalg = SGN_ALG_DES_MAC_MD5,
45 	  .sealalg = SEAL_ALG_DES,
46 	  .keybytes = 7,
47 	  .keylength = 8,
48 	  .blocksize = 8,
49 	  .conflen = 8,
50 	  .cksumlength = 8,
51 	  .keyed_cksum = 0,
52 	},
53 #endif	/* CONFIG_SUNRPC_DISABLE_INSECURE_ENCTYPES */
54 	/*
55 	 * RC4-HMAC
56 	 */
57 	{
58 	  .etype = ENCTYPE_ARCFOUR_HMAC,
59 	  .ctype = CKSUMTYPE_HMAC_MD5_ARCFOUR,
60 	  .name = "rc4-hmac",
61 	  .encrypt_name = "ecb(arc4)",
62 	  .cksum_name = "hmac(md5)",
63 	  .encrypt = krb5_encrypt,
64 	  .decrypt = krb5_decrypt,
65 	  .mk_key = NULL,
66 	  .signalg = SGN_ALG_HMAC_MD5,
67 	  .sealalg = SEAL_ALG_MICROSOFT_RC4,
68 	  .keybytes = 16,
69 	  .keylength = 16,
70 	  .blocksize = 1,
71 	  .conflen = 8,
72 	  .cksumlength = 8,
73 	  .keyed_cksum = 1,
74 	},
75 	/*
76 	 * 3DES
77 	 */
78 	{
79 	  .etype = ENCTYPE_DES3_CBC_RAW,
80 	  .ctype = CKSUMTYPE_HMAC_SHA1_DES3,
81 	  .name = "des3-hmac-sha1",
82 	  .encrypt_name = "cbc(des3_ede)",
83 	  .cksum_name = "hmac(sha1)",
84 	  .encrypt = krb5_encrypt,
85 	  .decrypt = krb5_decrypt,
86 	  .mk_key = gss_krb5_des3_make_key,
87 	  .signalg = SGN_ALG_HMAC_SHA1_DES3_KD,
88 	  .sealalg = SEAL_ALG_DES3KD,
89 	  .keybytes = 21,
90 	  .keylength = 24,
91 	  .blocksize = 8,
92 	  .conflen = 8,
93 	  .cksumlength = 20,
94 	  .keyed_cksum = 1,
95 	},
96 	/*
97 	 * AES128
98 	 */
99 	{
100 	  .etype = ENCTYPE_AES128_CTS_HMAC_SHA1_96,
101 	  .ctype = CKSUMTYPE_HMAC_SHA1_96_AES128,
102 	  .name = "aes128-cts",
103 	  .encrypt_name = "cts(cbc(aes))",
104 	  .cksum_name = "hmac(sha1)",
105 	  .encrypt = krb5_encrypt,
106 	  .decrypt = krb5_decrypt,
107 	  .mk_key = gss_krb5_aes_make_key,
108 	  .encrypt_v2 = gss_krb5_aes_encrypt,
109 	  .decrypt_v2 = gss_krb5_aes_decrypt,
110 	  .signalg = -1,
111 	  .sealalg = -1,
112 	  .keybytes = 16,
113 	  .keylength = 16,
114 	  .blocksize = 16,
115 	  .conflen = 16,
116 	  .cksumlength = 12,
117 	  .keyed_cksum = 1,
118 	},
119 	/*
120 	 * AES256
121 	 */
122 	{
123 	  .etype = ENCTYPE_AES256_CTS_HMAC_SHA1_96,
124 	  .ctype = CKSUMTYPE_HMAC_SHA1_96_AES256,
125 	  .name = "aes256-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 = 32,
136 	  .keylength = 32,
137 	  .blocksize = 16,
138 	  .conflen = 16,
139 	  .cksumlength = 12,
140 	  .keyed_cksum = 1,
141 	},
142 };
143 
144 static const int num_supported_enctypes =
145 	ARRAY_SIZE(supported_gss_krb5_enctypes);
146 
147 static int
148 supported_gss_krb5_enctype(int etype)
149 {
150 	int i;
151 	for (i = 0; i < num_supported_enctypes; i++)
152 		if (supported_gss_krb5_enctypes[i].etype == etype)
153 			return 1;
154 	return 0;
155 }
156 
157 static const struct gss_krb5_enctype *
158 get_gss_krb5_enctype(int etype)
159 {
160 	int i;
161 	for (i = 0; i < num_supported_enctypes; i++)
162 		if (supported_gss_krb5_enctypes[i].etype == etype)
163 			return &supported_gss_krb5_enctypes[i];
164 	return NULL;
165 }
166 
167 static const void *
168 simple_get_bytes(const void *p, const void *end, void *res, int len)
169 {
170 	const void *q = (const void *)((const char *)p + len);
171 	if (unlikely(q > end || q < p))
172 		return ERR_PTR(-EFAULT);
173 	memcpy(res, p, len);
174 	return q;
175 }
176 
177 static const void *
178 simple_get_netobj(const void *p, const void *end, struct xdr_netobj *res)
179 {
180 	const void *q;
181 	unsigned int len;
182 
183 	p = simple_get_bytes(p, end, &len, sizeof(len));
184 	if (IS_ERR(p))
185 		return p;
186 	q = (const void *)((const char *)p + len);
187 	if (unlikely(q > end || q < p))
188 		return ERR_PTR(-EFAULT);
189 	res->data = kmemdup(p, len, GFP_NOFS);
190 	if (unlikely(res->data == NULL))
191 		return ERR_PTR(-ENOMEM);
192 	res->len = len;
193 	return q;
194 }
195 
196 static inline const void *
197 get_key(const void *p, const void *end,
198 	struct krb5_ctx *ctx, struct crypto_sync_skcipher **res)
199 {
200 	struct xdr_netobj	key;
201 	int			alg;
202 
203 	p = simple_get_bytes(p, end, &alg, sizeof(alg));
204 	if (IS_ERR(p))
205 		goto out_err;
206 
207 	switch (alg) {
208 	case ENCTYPE_DES_CBC_CRC:
209 	case ENCTYPE_DES_CBC_MD4:
210 	case ENCTYPE_DES_CBC_MD5:
211 		/* Map all these key types to ENCTYPE_DES_CBC_RAW */
212 		alg = ENCTYPE_DES_CBC_RAW;
213 		break;
214 	}
215 
216 	if (!supported_gss_krb5_enctype(alg)) {
217 		printk(KERN_WARNING "gss_kerberos_mech: unsupported "
218 			"encryption key algorithm %d\n", alg);
219 		p = ERR_PTR(-EINVAL);
220 		goto out_err;
221 	}
222 	p = simple_get_netobj(p, end, &key);
223 	if (IS_ERR(p))
224 		goto out_err;
225 
226 	*res = crypto_alloc_sync_skcipher(ctx->gk5e->encrypt_name, 0, 0);
227 	if (IS_ERR(*res)) {
228 		printk(KERN_WARNING "gss_kerberos_mech: unable to initialize "
229 			"crypto algorithm %s\n", ctx->gk5e->encrypt_name);
230 		*res = NULL;
231 		goto out_err_free_key;
232 	}
233 	if (crypto_sync_skcipher_setkey(*res, key.data, key.len)) {
234 		printk(KERN_WARNING "gss_kerberos_mech: error setting key for "
235 			"crypto algorithm %s\n", ctx->gk5e->encrypt_name);
236 		goto out_err_free_tfm;
237 	}
238 
239 	kfree(key.data);
240 	return p;
241 
242 out_err_free_tfm:
243 	crypto_free_sync_skcipher(*res);
244 out_err_free_key:
245 	kfree(key.data);
246 	p = ERR_PTR(-EINVAL);
247 out_err:
248 	return p;
249 }
250 
251 static int
252 gss_import_v1_context(const void *p, const void *end, struct krb5_ctx *ctx)
253 {
254 	u32 seq_send;
255 	int tmp;
256 
257 	p = simple_get_bytes(p, end, &ctx->initiate, sizeof(ctx->initiate));
258 	if (IS_ERR(p))
259 		goto out_err;
260 
261 	/* Old format supports only DES!  Any other enctype uses new format */
262 	ctx->enctype = ENCTYPE_DES_CBC_RAW;
263 
264 	ctx->gk5e = get_gss_krb5_enctype(ctx->enctype);
265 	if (ctx->gk5e == NULL) {
266 		p = ERR_PTR(-EINVAL);
267 		goto out_err;
268 	}
269 
270 	/* The downcall format was designed before we completely understood
271 	 * the uses of the context fields; so it includes some stuff we
272 	 * just give some minimal sanity-checking, and some we ignore
273 	 * completely (like the next twenty bytes): */
274 	if (unlikely(p + 20 > end || p + 20 < p)) {
275 		p = ERR_PTR(-EFAULT);
276 		goto out_err;
277 	}
278 	p += 20;
279 	p = simple_get_bytes(p, end, &tmp, sizeof(tmp));
280 	if (IS_ERR(p))
281 		goto out_err;
282 	if (tmp != SGN_ALG_DES_MAC_MD5) {
283 		p = ERR_PTR(-ENOSYS);
284 		goto out_err;
285 	}
286 	p = simple_get_bytes(p, end, &tmp, sizeof(tmp));
287 	if (IS_ERR(p))
288 		goto out_err;
289 	if (tmp != SEAL_ALG_DES) {
290 		p = ERR_PTR(-ENOSYS);
291 		goto out_err;
292 	}
293 	p = simple_get_bytes(p, end, &ctx->endtime, sizeof(ctx->endtime));
294 	if (IS_ERR(p))
295 		goto out_err;
296 	p = simple_get_bytes(p, end, &seq_send, sizeof(seq_send));
297 	if (IS_ERR(p))
298 		goto out_err;
299 	atomic_set(&ctx->seq_send, seq_send);
300 	p = simple_get_netobj(p, end, &ctx->mech_used);
301 	if (IS_ERR(p))
302 		goto out_err;
303 	p = get_key(p, end, ctx, &ctx->enc);
304 	if (IS_ERR(p))
305 		goto out_err_free_mech;
306 	p = get_key(p, end, ctx, &ctx->seq);
307 	if (IS_ERR(p))
308 		goto out_err_free_key1;
309 	if (p != end) {
310 		p = ERR_PTR(-EFAULT);
311 		goto out_err_free_key2;
312 	}
313 
314 	return 0;
315 
316 out_err_free_key2:
317 	crypto_free_sync_skcipher(ctx->seq);
318 out_err_free_key1:
319 	crypto_free_sync_skcipher(ctx->enc);
320 out_err_free_mech:
321 	kfree(ctx->mech_used.data);
322 out_err:
323 	return PTR_ERR(p);
324 }
325 
326 static struct crypto_sync_skcipher *
327 context_v2_alloc_cipher(struct krb5_ctx *ctx, const char *cname, u8 *key)
328 {
329 	struct crypto_sync_skcipher *cp;
330 
331 	cp = crypto_alloc_sync_skcipher(cname, 0, 0);
332 	if (IS_ERR(cp)) {
333 		dprintk("gss_kerberos_mech: unable to initialize "
334 			"crypto algorithm %s\n", cname);
335 		return NULL;
336 	}
337 	if (crypto_sync_skcipher_setkey(cp, key, ctx->gk5e->keylength)) {
338 		dprintk("gss_kerberos_mech: error setting key for "
339 			"crypto algorithm %s\n", cname);
340 		crypto_free_sync_skcipher(cp);
341 		return NULL;
342 	}
343 	return cp;
344 }
345 
346 static inline void
347 set_cdata(u8 cdata[GSS_KRB5_K5CLENGTH], u32 usage, u8 seed)
348 {
349 	cdata[0] = (usage>>24)&0xff;
350 	cdata[1] = (usage>>16)&0xff;
351 	cdata[2] = (usage>>8)&0xff;
352 	cdata[3] = usage&0xff;
353 	cdata[4] = seed;
354 }
355 
356 static int
357 context_derive_keys_des3(struct krb5_ctx *ctx, gfp_t gfp_mask)
358 {
359 	struct xdr_netobj c, keyin, keyout;
360 	u8 cdata[GSS_KRB5_K5CLENGTH];
361 	u32 err;
362 
363 	c.len = GSS_KRB5_K5CLENGTH;
364 	c.data = cdata;
365 
366 	keyin.data = ctx->Ksess;
367 	keyin.len = ctx->gk5e->keylength;
368 	keyout.len = ctx->gk5e->keylength;
369 
370 	/* seq uses the raw key */
371 	ctx->seq = context_v2_alloc_cipher(ctx, ctx->gk5e->encrypt_name,
372 					   ctx->Ksess);
373 	if (ctx->seq == NULL)
374 		goto out_err;
375 
376 	ctx->enc = context_v2_alloc_cipher(ctx, ctx->gk5e->encrypt_name,
377 					   ctx->Ksess);
378 	if (ctx->enc == NULL)
379 		goto out_free_seq;
380 
381 	/* derive cksum */
382 	set_cdata(cdata, KG_USAGE_SIGN, KEY_USAGE_SEED_CHECKSUM);
383 	keyout.data = ctx->cksum;
384 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
385 	if (err) {
386 		dprintk("%s: Error %d deriving cksum key\n",
387 			__func__, err);
388 		goto out_free_enc;
389 	}
390 
391 	return 0;
392 
393 out_free_enc:
394 	crypto_free_sync_skcipher(ctx->enc);
395 out_free_seq:
396 	crypto_free_sync_skcipher(ctx->seq);
397 out_err:
398 	return -EINVAL;
399 }
400 
401 /*
402  * Note that RC4 depends on deriving keys using the sequence
403  * number or the checksum of a token.  Therefore, the final keys
404  * cannot be calculated until the token is being constructed!
405  */
406 static int
407 context_derive_keys_rc4(struct krb5_ctx *ctx)
408 {
409 	struct crypto_shash *hmac;
410 	char sigkeyconstant[] = "signaturekey";
411 	int slen = strlen(sigkeyconstant) + 1;	/* include null terminator */
412 	struct shash_desc *desc;
413 	int err;
414 
415 	dprintk("RPC:       %s: entered\n", __func__);
416 	/*
417 	 * derive cksum (aka Ksign) key
418 	 */
419 	hmac = crypto_alloc_shash(ctx->gk5e->cksum_name, 0, 0);
420 	if (IS_ERR(hmac)) {
421 		dprintk("%s: error %ld allocating hash '%s'\n",
422 			__func__, PTR_ERR(hmac), ctx->gk5e->cksum_name);
423 		err = PTR_ERR(hmac);
424 		goto out_err;
425 	}
426 
427 	err = crypto_shash_setkey(hmac, ctx->Ksess, ctx->gk5e->keylength);
428 	if (err)
429 		goto out_err_free_hmac;
430 
431 
432 	desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(hmac), GFP_NOFS);
433 	if (!desc) {
434 		dprintk("%s: failed to allocate hash descriptor for '%s'\n",
435 			__func__, ctx->gk5e->cksum_name);
436 		err = -ENOMEM;
437 		goto out_err_free_hmac;
438 	}
439 
440 	desc->tfm = hmac;
441 
442 	err = crypto_shash_digest(desc, sigkeyconstant, slen, ctx->cksum);
443 	kzfree(desc);
444 	if (err)
445 		goto out_err_free_hmac;
446 	/*
447 	 * allocate hash, and skciphers for data and seqnum encryption
448 	 */
449 	ctx->enc = crypto_alloc_sync_skcipher(ctx->gk5e->encrypt_name, 0, 0);
450 	if (IS_ERR(ctx->enc)) {
451 		err = PTR_ERR(ctx->enc);
452 		goto out_err_free_hmac;
453 	}
454 
455 	ctx->seq = crypto_alloc_sync_skcipher(ctx->gk5e->encrypt_name, 0, 0);
456 	if (IS_ERR(ctx->seq)) {
457 		crypto_free_sync_skcipher(ctx->enc);
458 		err = PTR_ERR(ctx->seq);
459 		goto out_err_free_hmac;
460 	}
461 
462 	dprintk("RPC:       %s: returning success\n", __func__);
463 
464 	err = 0;
465 
466 out_err_free_hmac:
467 	crypto_free_shash(hmac);
468 out_err:
469 	dprintk("RPC:       %s: returning %d\n", __func__, err);
470 	return err;
471 }
472 
473 static int
474 context_derive_keys_new(struct krb5_ctx *ctx, gfp_t gfp_mask)
475 {
476 	struct xdr_netobj c, keyin, keyout;
477 	u8 cdata[GSS_KRB5_K5CLENGTH];
478 	u32 err;
479 
480 	c.len = GSS_KRB5_K5CLENGTH;
481 	c.data = cdata;
482 
483 	keyin.data = ctx->Ksess;
484 	keyin.len = ctx->gk5e->keylength;
485 	keyout.len = ctx->gk5e->keylength;
486 
487 	/* initiator seal encryption */
488 	set_cdata(cdata, KG_USAGE_INITIATOR_SEAL, KEY_USAGE_SEED_ENCRYPTION);
489 	keyout.data = ctx->initiator_seal;
490 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
491 	if (err) {
492 		dprintk("%s: Error %d deriving initiator_seal key\n",
493 			__func__, err);
494 		goto out_err;
495 	}
496 	ctx->initiator_enc = context_v2_alloc_cipher(ctx,
497 						     ctx->gk5e->encrypt_name,
498 						     ctx->initiator_seal);
499 	if (ctx->initiator_enc == NULL)
500 		goto out_err;
501 
502 	/* acceptor seal encryption */
503 	set_cdata(cdata, KG_USAGE_ACCEPTOR_SEAL, KEY_USAGE_SEED_ENCRYPTION);
504 	keyout.data = ctx->acceptor_seal;
505 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
506 	if (err) {
507 		dprintk("%s: Error %d deriving acceptor_seal key\n",
508 			__func__, err);
509 		goto out_free_initiator_enc;
510 	}
511 	ctx->acceptor_enc = context_v2_alloc_cipher(ctx,
512 						    ctx->gk5e->encrypt_name,
513 						    ctx->acceptor_seal);
514 	if (ctx->acceptor_enc == NULL)
515 		goto out_free_initiator_enc;
516 
517 	/* initiator sign checksum */
518 	set_cdata(cdata, KG_USAGE_INITIATOR_SIGN, KEY_USAGE_SEED_CHECKSUM);
519 	keyout.data = ctx->initiator_sign;
520 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
521 	if (err) {
522 		dprintk("%s: Error %d deriving initiator_sign key\n",
523 			__func__, err);
524 		goto out_free_acceptor_enc;
525 	}
526 
527 	/* acceptor sign checksum */
528 	set_cdata(cdata, KG_USAGE_ACCEPTOR_SIGN, KEY_USAGE_SEED_CHECKSUM);
529 	keyout.data = ctx->acceptor_sign;
530 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
531 	if (err) {
532 		dprintk("%s: Error %d deriving acceptor_sign key\n",
533 			__func__, err);
534 		goto out_free_acceptor_enc;
535 	}
536 
537 	/* initiator seal integrity */
538 	set_cdata(cdata, KG_USAGE_INITIATOR_SEAL, KEY_USAGE_SEED_INTEGRITY);
539 	keyout.data = ctx->initiator_integ;
540 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
541 	if (err) {
542 		dprintk("%s: Error %d deriving initiator_integ key\n",
543 			__func__, err);
544 		goto out_free_acceptor_enc;
545 	}
546 
547 	/* acceptor seal integrity */
548 	set_cdata(cdata, KG_USAGE_ACCEPTOR_SEAL, KEY_USAGE_SEED_INTEGRITY);
549 	keyout.data = ctx->acceptor_integ;
550 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
551 	if (err) {
552 		dprintk("%s: Error %d deriving acceptor_integ key\n",
553 			__func__, err);
554 		goto out_free_acceptor_enc;
555 	}
556 
557 	switch (ctx->enctype) {
558 	case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
559 	case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
560 		ctx->initiator_enc_aux =
561 			context_v2_alloc_cipher(ctx, "cbc(aes)",
562 						ctx->initiator_seal);
563 		if (ctx->initiator_enc_aux == NULL)
564 			goto out_free_acceptor_enc;
565 		ctx->acceptor_enc_aux =
566 			context_v2_alloc_cipher(ctx, "cbc(aes)",
567 						ctx->acceptor_seal);
568 		if (ctx->acceptor_enc_aux == NULL) {
569 			crypto_free_sync_skcipher(ctx->initiator_enc_aux);
570 			goto out_free_acceptor_enc;
571 		}
572 	}
573 
574 	return 0;
575 
576 out_free_acceptor_enc:
577 	crypto_free_sync_skcipher(ctx->acceptor_enc);
578 out_free_initiator_enc:
579 	crypto_free_sync_skcipher(ctx->initiator_enc);
580 out_err:
581 	return -EINVAL;
582 }
583 
584 static int
585 gss_import_v2_context(const void *p, const void *end, struct krb5_ctx *ctx,
586 		gfp_t gfp_mask)
587 {
588 	u64 seq_send64;
589 	int keylen;
590 
591 	p = simple_get_bytes(p, end, &ctx->flags, sizeof(ctx->flags));
592 	if (IS_ERR(p))
593 		goto out_err;
594 	ctx->initiate = ctx->flags & KRB5_CTX_FLAG_INITIATOR;
595 
596 	p = simple_get_bytes(p, end, &ctx->endtime, sizeof(ctx->endtime));
597 	if (IS_ERR(p))
598 		goto out_err;
599 	p = simple_get_bytes(p, end, &seq_send64, sizeof(seq_send64));
600 	if (IS_ERR(p))
601 		goto out_err;
602 	atomic64_set(&ctx->seq_send64, seq_send64);
603 	/* set seq_send for use by "older" enctypes */
604 	atomic_set(&ctx->seq_send, seq_send64);
605 	if (seq_send64 != atomic_read(&ctx->seq_send)) {
606 		dprintk("%s: seq_send64 %llx, seq_send %x overflow?\n", __func__,
607 			seq_send64, atomic_read(&ctx->seq_send));
608 		p = ERR_PTR(-EINVAL);
609 		goto out_err;
610 	}
611 	p = simple_get_bytes(p, end, &ctx->enctype, sizeof(ctx->enctype));
612 	if (IS_ERR(p))
613 		goto out_err;
614 	/* Map ENCTYPE_DES3_CBC_SHA1 to ENCTYPE_DES3_CBC_RAW */
615 	if (ctx->enctype == ENCTYPE_DES3_CBC_SHA1)
616 		ctx->enctype = ENCTYPE_DES3_CBC_RAW;
617 	ctx->gk5e = get_gss_krb5_enctype(ctx->enctype);
618 	if (ctx->gk5e == NULL) {
619 		dprintk("gss_kerberos_mech: unsupported krb5 enctype %u\n",
620 			ctx->enctype);
621 		p = ERR_PTR(-EINVAL);
622 		goto out_err;
623 	}
624 	keylen = ctx->gk5e->keylength;
625 
626 	p = simple_get_bytes(p, end, ctx->Ksess, keylen);
627 	if (IS_ERR(p))
628 		goto out_err;
629 
630 	if (p != end) {
631 		p = ERR_PTR(-EINVAL);
632 		goto out_err;
633 	}
634 
635 	ctx->mech_used.data = kmemdup(gss_kerberos_mech.gm_oid.data,
636 				      gss_kerberos_mech.gm_oid.len, gfp_mask);
637 	if (unlikely(ctx->mech_used.data == NULL)) {
638 		p = ERR_PTR(-ENOMEM);
639 		goto out_err;
640 	}
641 	ctx->mech_used.len = gss_kerberos_mech.gm_oid.len;
642 
643 	switch (ctx->enctype) {
644 	case ENCTYPE_DES3_CBC_RAW:
645 		return context_derive_keys_des3(ctx, gfp_mask);
646 	case ENCTYPE_ARCFOUR_HMAC:
647 		return context_derive_keys_rc4(ctx);
648 	case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
649 	case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
650 		return context_derive_keys_new(ctx, gfp_mask);
651 	default:
652 		return -EINVAL;
653 	}
654 
655 out_err:
656 	return PTR_ERR(p);
657 }
658 
659 static int
660 gss_import_sec_context_kerberos(const void *p, size_t len,
661 				struct gss_ctx *ctx_id,
662 				time_t *endtime,
663 				gfp_t gfp_mask)
664 {
665 	const void *end = (const void *)((const char *)p + len);
666 	struct  krb5_ctx *ctx;
667 	int ret;
668 
669 	ctx = kzalloc(sizeof(*ctx), gfp_mask);
670 	if (ctx == NULL)
671 		return -ENOMEM;
672 
673 	if (len == 85)
674 		ret = gss_import_v1_context(p, end, ctx);
675 	else
676 		ret = gss_import_v2_context(p, end, ctx, gfp_mask);
677 
678 	if (ret == 0) {
679 		ctx_id->internal_ctx_id = ctx;
680 		if (endtime)
681 			*endtime = ctx->endtime;
682 	} else
683 		kfree(ctx);
684 
685 	dprintk("RPC:       %s: returning %d\n", __func__, ret);
686 	return ret;
687 }
688 
689 static void
690 gss_delete_sec_context_kerberos(void *internal_ctx) {
691 	struct krb5_ctx *kctx = internal_ctx;
692 
693 	crypto_free_sync_skcipher(kctx->seq);
694 	crypto_free_sync_skcipher(kctx->enc);
695 	crypto_free_sync_skcipher(kctx->acceptor_enc);
696 	crypto_free_sync_skcipher(kctx->initiator_enc);
697 	crypto_free_sync_skcipher(kctx->acceptor_enc_aux);
698 	crypto_free_sync_skcipher(kctx->initiator_enc_aux);
699 	kfree(kctx->mech_used.data);
700 	kfree(kctx);
701 }
702 
703 static const struct gss_api_ops gss_kerberos_ops = {
704 	.gss_import_sec_context	= gss_import_sec_context_kerberos,
705 	.gss_get_mic		= gss_get_mic_kerberos,
706 	.gss_verify_mic		= gss_verify_mic_kerberos,
707 	.gss_wrap		= gss_wrap_kerberos,
708 	.gss_unwrap		= gss_unwrap_kerberos,
709 	.gss_delete_sec_context	= gss_delete_sec_context_kerberos,
710 };
711 
712 static struct pf_desc gss_kerberos_pfs[] = {
713 	[0] = {
714 		.pseudoflavor = RPC_AUTH_GSS_KRB5,
715 		.qop = GSS_C_QOP_DEFAULT,
716 		.service = RPC_GSS_SVC_NONE,
717 		.name = "krb5",
718 	},
719 	[1] = {
720 		.pseudoflavor = RPC_AUTH_GSS_KRB5I,
721 		.qop = GSS_C_QOP_DEFAULT,
722 		.service = RPC_GSS_SVC_INTEGRITY,
723 		.name = "krb5i",
724 		.datatouch = true,
725 	},
726 	[2] = {
727 		.pseudoflavor = RPC_AUTH_GSS_KRB5P,
728 		.qop = GSS_C_QOP_DEFAULT,
729 		.service = RPC_GSS_SVC_PRIVACY,
730 		.name = "krb5p",
731 		.datatouch = true,
732 	},
733 };
734 
735 MODULE_ALIAS("rpc-auth-gss-krb5");
736 MODULE_ALIAS("rpc-auth-gss-krb5i");
737 MODULE_ALIAS("rpc-auth-gss-krb5p");
738 MODULE_ALIAS("rpc-auth-gss-390003");
739 MODULE_ALIAS("rpc-auth-gss-390004");
740 MODULE_ALIAS("rpc-auth-gss-390005");
741 MODULE_ALIAS("rpc-auth-gss-1.2.840.113554.1.2.2");
742 
743 static struct gss_api_mech gss_kerberos_mech = {
744 	.gm_name	= "krb5",
745 	.gm_owner	= THIS_MODULE,
746 	.gm_oid		= { 9, "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02" },
747 	.gm_ops		= &gss_kerberos_ops,
748 	.gm_pf_num	= ARRAY_SIZE(gss_kerberos_pfs),
749 	.gm_pfs		= gss_kerberos_pfs,
750 	.gm_upcall_enctypes = KRB5_SUPPORTED_ENCTYPES,
751 };
752 
753 static int __init init_kerberos_module(void)
754 {
755 	int status;
756 
757 	status = gss_mech_register(&gss_kerberos_mech);
758 	if (status)
759 		printk("Failed to register kerberos gss mechanism!\n");
760 	return status;
761 }
762 
763 static void __exit cleanup_kerberos_module(void)
764 {
765 	gss_mech_unregister(&gss_kerberos_mech);
766 }
767 
768 MODULE_LICENSE("GPL");
769 module_init(init_kerberos_module);
770 module_exit(cleanup_kerberos_module);
771