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 	u32 time32;
257 
258 	p = simple_get_bytes(p, end, &ctx->initiate, sizeof(ctx->initiate));
259 	if (IS_ERR(p))
260 		goto out_err;
261 
262 	/* Old format supports only DES!  Any other enctype uses new format */
263 	ctx->enctype = ENCTYPE_DES_CBC_RAW;
264 
265 	ctx->gk5e = get_gss_krb5_enctype(ctx->enctype);
266 	if (ctx->gk5e == NULL) {
267 		p = ERR_PTR(-EINVAL);
268 		goto out_err;
269 	}
270 
271 	/* The downcall format was designed before we completely understood
272 	 * the uses of the context fields; so it includes some stuff we
273 	 * just give some minimal sanity-checking, and some we ignore
274 	 * completely (like the next twenty bytes): */
275 	if (unlikely(p + 20 > end || p + 20 < p)) {
276 		p = ERR_PTR(-EFAULT);
277 		goto out_err;
278 	}
279 	p += 20;
280 	p = simple_get_bytes(p, end, &tmp, sizeof(tmp));
281 	if (IS_ERR(p))
282 		goto out_err;
283 	if (tmp != SGN_ALG_DES_MAC_MD5) {
284 		p = ERR_PTR(-ENOSYS);
285 		goto out_err;
286 	}
287 	p = simple_get_bytes(p, end, &tmp, sizeof(tmp));
288 	if (IS_ERR(p))
289 		goto out_err;
290 	if (tmp != SEAL_ALG_DES) {
291 		p = ERR_PTR(-ENOSYS);
292 		goto out_err;
293 	}
294 	p = simple_get_bytes(p, end, &time32, sizeof(time32));
295 	if (IS_ERR(p))
296 		goto out_err;
297 	/* unsigned 32-bit time overflows in year 2106 */
298 	ctx->endtime = (time64_t)time32;
299 	p = simple_get_bytes(p, end, &seq_send, sizeof(seq_send));
300 	if (IS_ERR(p))
301 		goto out_err;
302 	atomic_set(&ctx->seq_send, seq_send);
303 	p = simple_get_netobj(p, end, &ctx->mech_used);
304 	if (IS_ERR(p))
305 		goto out_err;
306 	p = get_key(p, end, ctx, &ctx->enc);
307 	if (IS_ERR(p))
308 		goto out_err_free_mech;
309 	p = get_key(p, end, ctx, &ctx->seq);
310 	if (IS_ERR(p))
311 		goto out_err_free_key1;
312 	if (p != end) {
313 		p = ERR_PTR(-EFAULT);
314 		goto out_err_free_key2;
315 	}
316 
317 	return 0;
318 
319 out_err_free_key2:
320 	crypto_free_sync_skcipher(ctx->seq);
321 out_err_free_key1:
322 	crypto_free_sync_skcipher(ctx->enc);
323 out_err_free_mech:
324 	kfree(ctx->mech_used.data);
325 out_err:
326 	return PTR_ERR(p);
327 }
328 
329 static struct crypto_sync_skcipher *
330 context_v2_alloc_cipher(struct krb5_ctx *ctx, const char *cname, u8 *key)
331 {
332 	struct crypto_sync_skcipher *cp;
333 
334 	cp = crypto_alloc_sync_skcipher(cname, 0, 0);
335 	if (IS_ERR(cp)) {
336 		dprintk("gss_kerberos_mech: unable to initialize "
337 			"crypto algorithm %s\n", cname);
338 		return NULL;
339 	}
340 	if (crypto_sync_skcipher_setkey(cp, key, ctx->gk5e->keylength)) {
341 		dprintk("gss_kerberos_mech: error setting key for "
342 			"crypto algorithm %s\n", cname);
343 		crypto_free_sync_skcipher(cp);
344 		return NULL;
345 	}
346 	return cp;
347 }
348 
349 static inline void
350 set_cdata(u8 cdata[GSS_KRB5_K5CLENGTH], u32 usage, u8 seed)
351 {
352 	cdata[0] = (usage>>24)&0xff;
353 	cdata[1] = (usage>>16)&0xff;
354 	cdata[2] = (usage>>8)&0xff;
355 	cdata[3] = usage&0xff;
356 	cdata[4] = seed;
357 }
358 
359 static int
360 context_derive_keys_des3(struct krb5_ctx *ctx, gfp_t gfp_mask)
361 {
362 	struct xdr_netobj c, keyin, keyout;
363 	u8 cdata[GSS_KRB5_K5CLENGTH];
364 	u32 err;
365 
366 	c.len = GSS_KRB5_K5CLENGTH;
367 	c.data = cdata;
368 
369 	keyin.data = ctx->Ksess;
370 	keyin.len = ctx->gk5e->keylength;
371 	keyout.len = ctx->gk5e->keylength;
372 
373 	/* seq uses the raw key */
374 	ctx->seq = context_v2_alloc_cipher(ctx, ctx->gk5e->encrypt_name,
375 					   ctx->Ksess);
376 	if (ctx->seq == NULL)
377 		goto out_err;
378 
379 	ctx->enc = context_v2_alloc_cipher(ctx, ctx->gk5e->encrypt_name,
380 					   ctx->Ksess);
381 	if (ctx->enc == NULL)
382 		goto out_free_seq;
383 
384 	/* derive cksum */
385 	set_cdata(cdata, KG_USAGE_SIGN, KEY_USAGE_SEED_CHECKSUM);
386 	keyout.data = ctx->cksum;
387 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
388 	if (err) {
389 		dprintk("%s: Error %d deriving cksum key\n",
390 			__func__, err);
391 		goto out_free_enc;
392 	}
393 
394 	return 0;
395 
396 out_free_enc:
397 	crypto_free_sync_skcipher(ctx->enc);
398 out_free_seq:
399 	crypto_free_sync_skcipher(ctx->seq);
400 out_err:
401 	return -EINVAL;
402 }
403 
404 /*
405  * Note that RC4 depends on deriving keys using the sequence
406  * number or the checksum of a token.  Therefore, the final keys
407  * cannot be calculated until the token is being constructed!
408  */
409 static int
410 context_derive_keys_rc4(struct krb5_ctx *ctx)
411 {
412 	struct crypto_shash *hmac;
413 	char sigkeyconstant[] = "signaturekey";
414 	int slen = strlen(sigkeyconstant) + 1;	/* include null terminator */
415 	struct shash_desc *desc;
416 	int err;
417 
418 	dprintk("RPC:       %s: entered\n", __func__);
419 	/*
420 	 * derive cksum (aka Ksign) key
421 	 */
422 	hmac = crypto_alloc_shash(ctx->gk5e->cksum_name, 0, 0);
423 	if (IS_ERR(hmac)) {
424 		dprintk("%s: error %ld allocating hash '%s'\n",
425 			__func__, PTR_ERR(hmac), ctx->gk5e->cksum_name);
426 		err = PTR_ERR(hmac);
427 		goto out_err;
428 	}
429 
430 	err = crypto_shash_setkey(hmac, ctx->Ksess, ctx->gk5e->keylength);
431 	if (err)
432 		goto out_err_free_hmac;
433 
434 
435 	desc = kmalloc(sizeof(*desc) + crypto_shash_descsize(hmac), GFP_NOFS);
436 	if (!desc) {
437 		dprintk("%s: failed to allocate hash descriptor for '%s'\n",
438 			__func__, ctx->gk5e->cksum_name);
439 		err = -ENOMEM;
440 		goto out_err_free_hmac;
441 	}
442 
443 	desc->tfm = hmac;
444 
445 	err = crypto_shash_digest(desc, sigkeyconstant, slen, ctx->cksum);
446 	kfree_sensitive(desc);
447 	if (err)
448 		goto out_err_free_hmac;
449 	/*
450 	 * allocate hash, and skciphers for data and seqnum encryption
451 	 */
452 	ctx->enc = crypto_alloc_sync_skcipher(ctx->gk5e->encrypt_name, 0, 0);
453 	if (IS_ERR(ctx->enc)) {
454 		err = PTR_ERR(ctx->enc);
455 		goto out_err_free_hmac;
456 	}
457 
458 	ctx->seq = crypto_alloc_sync_skcipher(ctx->gk5e->encrypt_name, 0, 0);
459 	if (IS_ERR(ctx->seq)) {
460 		crypto_free_sync_skcipher(ctx->enc);
461 		err = PTR_ERR(ctx->seq);
462 		goto out_err_free_hmac;
463 	}
464 
465 	dprintk("RPC:       %s: returning success\n", __func__);
466 
467 	err = 0;
468 
469 out_err_free_hmac:
470 	crypto_free_shash(hmac);
471 out_err:
472 	dprintk("RPC:       %s: returning %d\n", __func__, err);
473 	return err;
474 }
475 
476 static int
477 context_derive_keys_new(struct krb5_ctx *ctx, gfp_t gfp_mask)
478 {
479 	struct xdr_netobj c, keyin, keyout;
480 	u8 cdata[GSS_KRB5_K5CLENGTH];
481 	u32 err;
482 
483 	c.len = GSS_KRB5_K5CLENGTH;
484 	c.data = cdata;
485 
486 	keyin.data = ctx->Ksess;
487 	keyin.len = ctx->gk5e->keylength;
488 	keyout.len = ctx->gk5e->keylength;
489 
490 	/* initiator seal encryption */
491 	set_cdata(cdata, KG_USAGE_INITIATOR_SEAL, KEY_USAGE_SEED_ENCRYPTION);
492 	keyout.data = ctx->initiator_seal;
493 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
494 	if (err) {
495 		dprintk("%s: Error %d deriving initiator_seal key\n",
496 			__func__, err);
497 		goto out_err;
498 	}
499 	ctx->initiator_enc = context_v2_alloc_cipher(ctx,
500 						     ctx->gk5e->encrypt_name,
501 						     ctx->initiator_seal);
502 	if (ctx->initiator_enc == NULL)
503 		goto out_err;
504 
505 	/* acceptor seal encryption */
506 	set_cdata(cdata, KG_USAGE_ACCEPTOR_SEAL, KEY_USAGE_SEED_ENCRYPTION);
507 	keyout.data = ctx->acceptor_seal;
508 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
509 	if (err) {
510 		dprintk("%s: Error %d deriving acceptor_seal key\n",
511 			__func__, err);
512 		goto out_free_initiator_enc;
513 	}
514 	ctx->acceptor_enc = context_v2_alloc_cipher(ctx,
515 						    ctx->gk5e->encrypt_name,
516 						    ctx->acceptor_seal);
517 	if (ctx->acceptor_enc == NULL)
518 		goto out_free_initiator_enc;
519 
520 	/* initiator sign checksum */
521 	set_cdata(cdata, KG_USAGE_INITIATOR_SIGN, KEY_USAGE_SEED_CHECKSUM);
522 	keyout.data = ctx->initiator_sign;
523 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
524 	if (err) {
525 		dprintk("%s: Error %d deriving initiator_sign key\n",
526 			__func__, err);
527 		goto out_free_acceptor_enc;
528 	}
529 
530 	/* acceptor sign checksum */
531 	set_cdata(cdata, KG_USAGE_ACCEPTOR_SIGN, KEY_USAGE_SEED_CHECKSUM);
532 	keyout.data = ctx->acceptor_sign;
533 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
534 	if (err) {
535 		dprintk("%s: Error %d deriving acceptor_sign key\n",
536 			__func__, err);
537 		goto out_free_acceptor_enc;
538 	}
539 
540 	/* initiator seal integrity */
541 	set_cdata(cdata, KG_USAGE_INITIATOR_SEAL, KEY_USAGE_SEED_INTEGRITY);
542 	keyout.data = ctx->initiator_integ;
543 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
544 	if (err) {
545 		dprintk("%s: Error %d deriving initiator_integ key\n",
546 			__func__, err);
547 		goto out_free_acceptor_enc;
548 	}
549 
550 	/* acceptor seal integrity */
551 	set_cdata(cdata, KG_USAGE_ACCEPTOR_SEAL, KEY_USAGE_SEED_INTEGRITY);
552 	keyout.data = ctx->acceptor_integ;
553 	err = krb5_derive_key(ctx->gk5e, &keyin, &keyout, &c, gfp_mask);
554 	if (err) {
555 		dprintk("%s: Error %d deriving acceptor_integ key\n",
556 			__func__, err);
557 		goto out_free_acceptor_enc;
558 	}
559 
560 	switch (ctx->enctype) {
561 	case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
562 	case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
563 		ctx->initiator_enc_aux =
564 			context_v2_alloc_cipher(ctx, "cbc(aes)",
565 						ctx->initiator_seal);
566 		if (ctx->initiator_enc_aux == NULL)
567 			goto out_free_acceptor_enc;
568 		ctx->acceptor_enc_aux =
569 			context_v2_alloc_cipher(ctx, "cbc(aes)",
570 						ctx->acceptor_seal);
571 		if (ctx->acceptor_enc_aux == NULL) {
572 			crypto_free_sync_skcipher(ctx->initiator_enc_aux);
573 			goto out_free_acceptor_enc;
574 		}
575 	}
576 
577 	return 0;
578 
579 out_free_acceptor_enc:
580 	crypto_free_sync_skcipher(ctx->acceptor_enc);
581 out_free_initiator_enc:
582 	crypto_free_sync_skcipher(ctx->initiator_enc);
583 out_err:
584 	return -EINVAL;
585 }
586 
587 static int
588 gss_import_v2_context(const void *p, const void *end, struct krb5_ctx *ctx,
589 		gfp_t gfp_mask)
590 {
591 	u64 seq_send64;
592 	int keylen;
593 	u32 time32;
594 
595 	p = simple_get_bytes(p, end, &ctx->flags, sizeof(ctx->flags));
596 	if (IS_ERR(p))
597 		goto out_err;
598 	ctx->initiate = ctx->flags & KRB5_CTX_FLAG_INITIATOR;
599 
600 	p = simple_get_bytes(p, end, &time32, sizeof(time32));
601 	if (IS_ERR(p))
602 		goto out_err;
603 	/* unsigned 32-bit time overflows in year 2106 */
604 	ctx->endtime = (time64_t)time32;
605 	p = simple_get_bytes(p, end, &seq_send64, sizeof(seq_send64));
606 	if (IS_ERR(p))
607 		goto out_err;
608 	atomic64_set(&ctx->seq_send64, seq_send64);
609 	/* set seq_send for use by "older" enctypes */
610 	atomic_set(&ctx->seq_send, seq_send64);
611 	if (seq_send64 != atomic_read(&ctx->seq_send)) {
612 		dprintk("%s: seq_send64 %llx, seq_send %x overflow?\n", __func__,
613 			seq_send64, atomic_read(&ctx->seq_send));
614 		p = ERR_PTR(-EINVAL);
615 		goto out_err;
616 	}
617 	p = simple_get_bytes(p, end, &ctx->enctype, sizeof(ctx->enctype));
618 	if (IS_ERR(p))
619 		goto out_err;
620 	/* Map ENCTYPE_DES3_CBC_SHA1 to ENCTYPE_DES3_CBC_RAW */
621 	if (ctx->enctype == ENCTYPE_DES3_CBC_SHA1)
622 		ctx->enctype = ENCTYPE_DES3_CBC_RAW;
623 	ctx->gk5e = get_gss_krb5_enctype(ctx->enctype);
624 	if (ctx->gk5e == NULL) {
625 		dprintk("gss_kerberos_mech: unsupported krb5 enctype %u\n",
626 			ctx->enctype);
627 		p = ERR_PTR(-EINVAL);
628 		goto out_err;
629 	}
630 	keylen = ctx->gk5e->keylength;
631 
632 	p = simple_get_bytes(p, end, ctx->Ksess, keylen);
633 	if (IS_ERR(p))
634 		goto out_err;
635 
636 	if (p != end) {
637 		p = ERR_PTR(-EINVAL);
638 		goto out_err;
639 	}
640 
641 	ctx->mech_used.data = kmemdup(gss_kerberos_mech.gm_oid.data,
642 				      gss_kerberos_mech.gm_oid.len, gfp_mask);
643 	if (unlikely(ctx->mech_used.data == NULL)) {
644 		p = ERR_PTR(-ENOMEM);
645 		goto out_err;
646 	}
647 	ctx->mech_used.len = gss_kerberos_mech.gm_oid.len;
648 
649 	switch (ctx->enctype) {
650 	case ENCTYPE_DES3_CBC_RAW:
651 		return context_derive_keys_des3(ctx, gfp_mask);
652 	case ENCTYPE_ARCFOUR_HMAC:
653 		return context_derive_keys_rc4(ctx);
654 	case ENCTYPE_AES128_CTS_HMAC_SHA1_96:
655 	case ENCTYPE_AES256_CTS_HMAC_SHA1_96:
656 		return context_derive_keys_new(ctx, gfp_mask);
657 	default:
658 		return -EINVAL;
659 	}
660 
661 out_err:
662 	return PTR_ERR(p);
663 }
664 
665 static int
666 gss_import_sec_context_kerberos(const void *p, size_t len,
667 				struct gss_ctx *ctx_id,
668 				time64_t *endtime,
669 				gfp_t gfp_mask)
670 {
671 	const void *end = (const void *)((const char *)p + len);
672 	struct  krb5_ctx *ctx;
673 	int ret;
674 
675 	ctx = kzalloc(sizeof(*ctx), gfp_mask);
676 	if (ctx == NULL)
677 		return -ENOMEM;
678 
679 	if (len == 85)
680 		ret = gss_import_v1_context(p, end, ctx);
681 	else
682 		ret = gss_import_v2_context(p, end, ctx, gfp_mask);
683 
684 	if (ret == 0) {
685 		ctx_id->internal_ctx_id = ctx;
686 		if (endtime)
687 			*endtime = ctx->endtime;
688 	} else
689 		kfree(ctx);
690 
691 	dprintk("RPC:       %s: returning %d\n", __func__, ret);
692 	return ret;
693 }
694 
695 static void
696 gss_delete_sec_context_kerberos(void *internal_ctx) {
697 	struct krb5_ctx *kctx = internal_ctx;
698 
699 	crypto_free_sync_skcipher(kctx->seq);
700 	crypto_free_sync_skcipher(kctx->enc);
701 	crypto_free_sync_skcipher(kctx->acceptor_enc);
702 	crypto_free_sync_skcipher(kctx->initiator_enc);
703 	crypto_free_sync_skcipher(kctx->acceptor_enc_aux);
704 	crypto_free_sync_skcipher(kctx->initiator_enc_aux);
705 	kfree(kctx->mech_used.data);
706 	kfree(kctx);
707 }
708 
709 static const struct gss_api_ops gss_kerberos_ops = {
710 	.gss_import_sec_context	= gss_import_sec_context_kerberos,
711 	.gss_get_mic		= gss_get_mic_kerberos,
712 	.gss_verify_mic		= gss_verify_mic_kerberos,
713 	.gss_wrap		= gss_wrap_kerberos,
714 	.gss_unwrap		= gss_unwrap_kerberos,
715 	.gss_delete_sec_context	= gss_delete_sec_context_kerberos,
716 };
717 
718 static struct pf_desc gss_kerberos_pfs[] = {
719 	[0] = {
720 		.pseudoflavor = RPC_AUTH_GSS_KRB5,
721 		.qop = GSS_C_QOP_DEFAULT,
722 		.service = RPC_GSS_SVC_NONE,
723 		.name = "krb5",
724 	},
725 	[1] = {
726 		.pseudoflavor = RPC_AUTH_GSS_KRB5I,
727 		.qop = GSS_C_QOP_DEFAULT,
728 		.service = RPC_GSS_SVC_INTEGRITY,
729 		.name = "krb5i",
730 		.datatouch = true,
731 	},
732 	[2] = {
733 		.pseudoflavor = RPC_AUTH_GSS_KRB5P,
734 		.qop = GSS_C_QOP_DEFAULT,
735 		.service = RPC_GSS_SVC_PRIVACY,
736 		.name = "krb5p",
737 		.datatouch = true,
738 	},
739 };
740 
741 MODULE_ALIAS("rpc-auth-gss-krb5");
742 MODULE_ALIAS("rpc-auth-gss-krb5i");
743 MODULE_ALIAS("rpc-auth-gss-krb5p");
744 MODULE_ALIAS("rpc-auth-gss-390003");
745 MODULE_ALIAS("rpc-auth-gss-390004");
746 MODULE_ALIAS("rpc-auth-gss-390005");
747 MODULE_ALIAS("rpc-auth-gss-1.2.840.113554.1.2.2");
748 
749 static struct gss_api_mech gss_kerberos_mech = {
750 	.gm_name	= "krb5",
751 	.gm_owner	= THIS_MODULE,
752 	.gm_oid		= { 9, "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02" },
753 	.gm_ops		= &gss_kerberos_ops,
754 	.gm_pf_num	= ARRAY_SIZE(gss_kerberos_pfs),
755 	.gm_pfs		= gss_kerberos_pfs,
756 	.gm_upcall_enctypes = KRB5_SUPPORTED_ENCTYPES,
757 };
758 
759 static int __init init_kerberos_module(void)
760 {
761 	int status;
762 
763 	status = gss_mech_register(&gss_kerberos_mech);
764 	if (status)
765 		printk("Failed to register kerberos gss mechanism!\n");
766 	return status;
767 }
768 
769 static void __exit cleanup_kerberos_module(void)
770 {
771 	gss_mech_unregister(&gss_kerberos_mech);
772 }
773 
774 MODULE_LICENSE("GPL");
775 module_init(init_kerberos_module);
776 module_exit(cleanup_kerberos_module);
777