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 <kunit/visibility.h>
23 
24 #include "auth_gss_internal.h"
25 #include "gss_krb5_internal.h"
26 
27 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
28 # define RPCDBG_FACILITY	RPCDBG_AUTH
29 #endif
30 
31 static struct gss_api_mech gss_kerberos_mech;
32 
33 #if defined(CONFIG_RPCSEC_GSS_KRB5_SIMPLIFIED)
34 static int gss_krb5_import_ctx_des(struct krb5_ctx *ctx, gfp_t gfp_mask);
35 static int gss_krb5_import_ctx_v1(struct krb5_ctx *ctx, gfp_t gfp_mask);
36 #endif
37 #if defined(CONFIG_RPCSEC_GSS_KRB5_CRYPTOSYSTEM)
38 static int gss_krb5_import_ctx_v2(struct krb5_ctx *ctx, gfp_t gfp_mask);
39 #endif
40 
41 static const struct gss_krb5_enctype supported_gss_krb5_enctypes[] = {
42 #if defined(CONFIG_RPCSEC_GSS_KRB5_ENCTYPES_DES)
43 	/*
44 	 * DES (All DES enctypes are mapped to the same gss functionality)
45 	 */
46 	{
47 	  .etype = ENCTYPE_DES_CBC_RAW,
48 	  .ctype = CKSUMTYPE_RSA_MD5,
49 	  .name = "des-cbc-crc",
50 	  .encrypt_name = "cbc(des)",
51 	  .cksum_name = "md5",
52 	  .import_ctx = gss_krb5_import_ctx_des,
53 	  .get_mic = gss_krb5_get_mic_v1,
54 	  .verify_mic = gss_krb5_verify_mic_v1,
55 	  .wrap = gss_krb5_wrap_v1,
56 	  .unwrap = gss_krb5_unwrap_v1,
57 	  .signalg = SGN_ALG_DES_MAC_MD5,
58 	  .sealalg = SEAL_ALG_DES,
59 	  .keybytes = 7,
60 	  .keylength = 8,
61 	  .cksumlength = 8,
62 	  .keyed_cksum = 0,
63 	},
64 	/*
65 	 * 3DES
66 	 */
67 	{
68 	  .etype = ENCTYPE_DES3_CBC_RAW,
69 	  .ctype = CKSUMTYPE_HMAC_SHA1_DES3,
70 	  .name = "des3-hmac-sha1",
71 	  .encrypt_name = "cbc(des3_ede)",
72 	  .cksum_name = "hmac(sha1)",
73 	  .import_ctx = gss_krb5_import_ctx_v1,
74 	  .derive_key = krb5_derive_key_v1,
75 	  .get_mic = gss_krb5_get_mic_v1,
76 	  .verify_mic = gss_krb5_verify_mic_v1,
77 	  .wrap = gss_krb5_wrap_v1,
78 	  .unwrap = gss_krb5_unwrap_v1,
79 	  .signalg = SGN_ALG_HMAC_SHA1_DES3_KD,
80 	  .sealalg = SEAL_ALG_DES3KD,
81 	  .keybytes = 21,
82 	  .keylength = 24,
83 	  .cksumlength = 20,
84 	  .keyed_cksum = 1,
85 	},
86 #endif
87 
88 #if defined(CONFIG_RPCSEC_GSS_KRB5_ENCTYPES_AES_SHA1)
89 	/*
90 	 * AES-128 with SHA-1 (RFC 3962)
91 	 */
92 	{
93 	  .etype = ENCTYPE_AES128_CTS_HMAC_SHA1_96,
94 	  .ctype = CKSUMTYPE_HMAC_SHA1_96_AES128,
95 	  .name = "aes128-cts",
96 	  .encrypt_name = "cts(cbc(aes))",
97 	  .aux_cipher = "cbc(aes)",
98 	  .cksum_name = "hmac(sha1)",
99 	  .import_ctx = gss_krb5_import_ctx_v2,
100 	  .derive_key = krb5_derive_key_v2,
101 	  .encrypt = gss_krb5_aes_encrypt,
102 	  .decrypt = gss_krb5_aes_decrypt,
103 
104 	  .get_mic = gss_krb5_get_mic_v2,
105 	  .verify_mic = gss_krb5_verify_mic_v2,
106 	  .wrap = gss_krb5_wrap_v2,
107 	  .unwrap = gss_krb5_unwrap_v2,
108 
109 	  .signalg = -1,
110 	  .sealalg = -1,
111 	  .keybytes = 16,
112 	  .keylength = BITS2OCTETS(128),
113 	  .Kc_length = BITS2OCTETS(128),
114 	  .Ke_length = BITS2OCTETS(128),
115 	  .Ki_length = BITS2OCTETS(128),
116 	  .cksumlength = BITS2OCTETS(96),
117 	  .keyed_cksum = 1,
118 	},
119 	/*
120 	 * AES-256 with SHA-1 (RFC 3962)
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 	  .aux_cipher = "cbc(aes)",
128 	  .cksum_name = "hmac(sha1)",
129 	  .import_ctx = gss_krb5_import_ctx_v2,
130 	  .derive_key = krb5_derive_key_v2,
131 	  .encrypt = gss_krb5_aes_encrypt,
132 	  .decrypt = gss_krb5_aes_decrypt,
133 
134 	  .get_mic = gss_krb5_get_mic_v2,
135 	  .verify_mic = gss_krb5_verify_mic_v2,
136 	  .wrap = gss_krb5_wrap_v2,
137 	  .unwrap = gss_krb5_unwrap_v2,
138 
139 	  .signalg = -1,
140 	  .sealalg = -1,
141 	  .keybytes = 32,
142 	  .keylength = BITS2OCTETS(256),
143 	  .Kc_length = BITS2OCTETS(256),
144 	  .Ke_length = BITS2OCTETS(256),
145 	  .Ki_length = BITS2OCTETS(256),
146 	  .cksumlength = BITS2OCTETS(96),
147 	  .keyed_cksum = 1,
148 	},
149 #endif
150 
151 #if defined(CONFIG_RPCSEC_GSS_KRB5_ENCTYPES_CAMELLIA)
152 	/*
153 	 * Camellia-128 with CMAC (RFC 6803)
154 	 */
155 	{
156 		.etype		= ENCTYPE_CAMELLIA128_CTS_CMAC,
157 		.ctype		= CKSUMTYPE_CMAC_CAMELLIA128,
158 		.name		= "camellia128-cts-cmac",
159 		.encrypt_name	= "cts(cbc(camellia))",
160 		.aux_cipher	= "cbc(camellia)",
161 		.cksum_name	= "cmac(camellia)",
162 		.cksumlength	= BITS2OCTETS(128),
163 		.keyed_cksum	= 1,
164 		.keylength	= BITS2OCTETS(128),
165 		.Kc_length	= BITS2OCTETS(128),
166 		.Ke_length	= BITS2OCTETS(128),
167 		.Ki_length	= BITS2OCTETS(128),
168 
169 		.import_ctx	= gss_krb5_import_ctx_v2,
170 		.derive_key	= krb5_kdf_feedback_cmac,
171 		.encrypt	= gss_krb5_aes_encrypt,
172 		.decrypt	= gss_krb5_aes_decrypt,
173 
174 		.get_mic	= gss_krb5_get_mic_v2,
175 		.verify_mic	= gss_krb5_verify_mic_v2,
176 		.wrap		= gss_krb5_wrap_v2,
177 		.unwrap		= gss_krb5_unwrap_v2,
178 	},
179 	/*
180 	 * Camellia-256 with CMAC (RFC 6803)
181 	 */
182 	{
183 		.etype		= ENCTYPE_CAMELLIA256_CTS_CMAC,
184 		.ctype		= CKSUMTYPE_CMAC_CAMELLIA256,
185 		.name		= "camellia256-cts-cmac",
186 		.encrypt_name	= "cts(cbc(camellia))",
187 		.aux_cipher	= "cbc(camellia)",
188 		.cksum_name	= "cmac(camellia)",
189 		.cksumlength	= BITS2OCTETS(128),
190 		.keyed_cksum	= 1,
191 		.keylength	= BITS2OCTETS(256),
192 		.Kc_length	= BITS2OCTETS(256),
193 		.Ke_length	= BITS2OCTETS(256),
194 		.Ki_length	= BITS2OCTETS(256),
195 
196 		.import_ctx	= gss_krb5_import_ctx_v2,
197 		.derive_key	= krb5_kdf_feedback_cmac,
198 		.encrypt	= gss_krb5_aes_encrypt,
199 		.decrypt	= gss_krb5_aes_decrypt,
200 
201 		.get_mic	= gss_krb5_get_mic_v2,
202 		.verify_mic	= gss_krb5_verify_mic_v2,
203 		.wrap		= gss_krb5_wrap_v2,
204 		.unwrap		= gss_krb5_unwrap_v2,
205 	},
206 #endif
207 
208 #if defined(CONFIG_RPCSEC_GSS_KRB5_ENCTYPES_AES_SHA2)
209 	/*
210 	 * AES-128 with SHA-256 (RFC 8009)
211 	 */
212 	{
213 		.etype		= ENCTYPE_AES128_CTS_HMAC_SHA256_128,
214 		.ctype		= CKSUMTYPE_HMAC_SHA256_128_AES128,
215 		.name		= "aes128-cts-hmac-sha256-128",
216 		.encrypt_name	= "cts(cbc(aes))",
217 		.aux_cipher	= "cbc(aes)",
218 		.cksum_name	= "hmac(sha256)",
219 		.cksumlength	= BITS2OCTETS(128),
220 		.keyed_cksum	= 1,
221 		.keylength	= BITS2OCTETS(128),
222 		.Kc_length	= BITS2OCTETS(128),
223 		.Ke_length	= BITS2OCTETS(128),
224 		.Ki_length	= BITS2OCTETS(128),
225 
226 		.import_ctx	= gss_krb5_import_ctx_v2,
227 		.derive_key	= krb5_kdf_hmac_sha2,
228 		.encrypt	= krb5_etm_encrypt,
229 		.decrypt	= krb5_etm_decrypt,
230 
231 		.get_mic	= gss_krb5_get_mic_v2,
232 		.verify_mic	= gss_krb5_verify_mic_v2,
233 		.wrap		= gss_krb5_wrap_v2,
234 		.unwrap		= gss_krb5_unwrap_v2,
235 	},
236 	/*
237 	 * AES-256 with SHA-384 (RFC 8009)
238 	 */
239 	{
240 		.etype		= ENCTYPE_AES256_CTS_HMAC_SHA384_192,
241 		.ctype		= CKSUMTYPE_HMAC_SHA384_192_AES256,
242 		.name		= "aes256-cts-hmac-sha384-192",
243 		.encrypt_name	= "cts(cbc(aes))",
244 		.aux_cipher	= "cbc(aes)",
245 		.cksum_name	= "hmac(sha384)",
246 		.cksumlength	= BITS2OCTETS(192),
247 		.keyed_cksum	= 1,
248 		.keylength	= BITS2OCTETS(256),
249 		.Kc_length	= BITS2OCTETS(192),
250 		.Ke_length	= BITS2OCTETS(256),
251 		.Ki_length	= BITS2OCTETS(192),
252 
253 		.import_ctx	= gss_krb5_import_ctx_v2,
254 		.derive_key	= krb5_kdf_hmac_sha2,
255 		.encrypt	= krb5_etm_encrypt,
256 		.decrypt	= krb5_etm_decrypt,
257 
258 		.get_mic	= gss_krb5_get_mic_v2,
259 		.verify_mic	= gss_krb5_verify_mic_v2,
260 		.wrap		= gss_krb5_wrap_v2,
261 		.unwrap		= gss_krb5_unwrap_v2,
262 	},
263 #endif
264 };
265 
266 /*
267  * The list of advertised enctypes is specified in order of most
268  * preferred to least.
269  */
270 static char gss_krb5_enctype_priority_list[64];
271 
272 static void gss_krb5_prepare_enctype_priority_list(void)
273 {
274 	static const u32 gss_krb5_enctypes[] = {
275 #if defined(CONFIG_RPCSEC_GSS_KRB5_ENCTYPES_AES_SHA2)
276 		ENCTYPE_AES256_CTS_HMAC_SHA384_192,
277 		ENCTYPE_AES128_CTS_HMAC_SHA256_128,
278 #endif
279 #if defined(CONFIG_RPCSEC_GSS_KRB5_ENCTYPES_CAMELLIA)
280 		ENCTYPE_CAMELLIA256_CTS_CMAC,
281 		ENCTYPE_CAMELLIA128_CTS_CMAC,
282 #endif
283 #if defined(CONFIG_RPCSEC_GSS_KRB5_ENCTYPES_AES_SHA1)
284 		ENCTYPE_AES256_CTS_HMAC_SHA1_96,
285 		ENCTYPE_AES128_CTS_HMAC_SHA1_96,
286 #endif
287 #if defined(CONFIG_RPCSEC_GSS_KRB5_ENCTYPES_DES)
288 		ENCTYPE_DES3_CBC_SHA1,
289 		ENCTYPE_DES_CBC_MD5,
290 		ENCTYPE_DES_CBC_CRC,
291 		ENCTYPE_DES_CBC_MD4,
292 #endif
293 	};
294 	size_t total, i;
295 	char buf[16];
296 	char *sep;
297 	int n;
298 
299 	sep = "";
300 	gss_krb5_enctype_priority_list[0] = '\0';
301 	for (total = 0, i = 0; i < ARRAY_SIZE(gss_krb5_enctypes); i++) {
302 		n = sprintf(buf, "%s%u", sep, gss_krb5_enctypes[i]);
303 		if (n < 0)
304 			break;
305 		if (total + n >= sizeof(gss_krb5_enctype_priority_list))
306 			break;
307 		strcat(gss_krb5_enctype_priority_list, buf);
308 		sep = ",";
309 		total += n;
310 	}
311 }
312 
313 /**
314  * gss_krb5_lookup_enctype - Retrieve profile information for a given enctype
315  * @etype: ENCTYPE value
316  *
317  * Returns a pointer to a gss_krb5_enctype structure, or NULL if no
318  * matching etype is found.
319  */
320 VISIBLE_IF_KUNIT
321 const struct gss_krb5_enctype *gss_krb5_lookup_enctype(u32 etype)
322 {
323 	size_t i;
324 
325 	for (i = 0; i < ARRAY_SIZE(supported_gss_krb5_enctypes); i++)
326 		if (supported_gss_krb5_enctypes[i].etype == etype)
327 			return &supported_gss_krb5_enctypes[i];
328 	return NULL;
329 }
330 EXPORT_SYMBOL_IF_KUNIT(gss_krb5_lookup_enctype);
331 
332 static struct crypto_sync_skcipher *
333 gss_krb5_alloc_cipher_v1(struct krb5_ctx *ctx, struct xdr_netobj *key)
334 {
335 	struct crypto_sync_skcipher *tfm;
336 
337 	tfm = crypto_alloc_sync_skcipher(ctx->gk5e->encrypt_name, 0, 0);
338 	if (IS_ERR(tfm))
339 		return NULL;
340 	if (crypto_sync_skcipher_setkey(tfm, key->data, key->len)) {
341 		crypto_free_sync_skcipher(tfm);
342 		return NULL;
343 	}
344 	return tfm;
345 }
346 
347 static inline const void *
348 get_key(const void *p, const void *end,
349 	struct krb5_ctx *ctx, struct crypto_sync_skcipher **res)
350 {
351 	struct crypto_sync_skcipher *tfm;
352 	struct xdr_netobj	key;
353 	int			alg;
354 
355 	p = simple_get_bytes(p, end, &alg, sizeof(alg));
356 	if (IS_ERR(p))
357 		goto out_err;
358 	switch (alg) {
359 	case ENCTYPE_DES_CBC_CRC:
360 	case ENCTYPE_DES_CBC_MD4:
361 	case ENCTYPE_DES_CBC_MD5:
362 		/* Map all these key types to ENCTYPE_DES_CBC_RAW */
363 		alg = ENCTYPE_DES_CBC_RAW;
364 		break;
365 	}
366 	if (!gss_krb5_lookup_enctype(alg)) {
367 		pr_warn("gss_krb5: unsupported enctype: %d\n", alg);
368 		goto out_err_inval;
369 	}
370 
371 	p = simple_get_netobj(p, end, &key);
372 	if (IS_ERR(p))
373 		goto out_err;
374 	tfm = gss_krb5_alloc_cipher_v1(ctx, &key);
375 	kfree(key.data);
376 	if (!tfm) {
377 		pr_warn("gss_krb5: failed to initialize cipher '%s'\n",
378 			ctx->gk5e->encrypt_name);
379 		goto out_err_inval;
380 	}
381 	*res = tfm;
382 
383 	return p;
384 
385 out_err_inval:
386 	p = ERR_PTR(-EINVAL);
387 out_err:
388 	return p;
389 }
390 
391 static int
392 gss_import_v1_context(const void *p, const void *end, struct krb5_ctx *ctx)
393 {
394 	u32 seq_send;
395 	int tmp;
396 	u32 time32;
397 
398 	p = simple_get_bytes(p, end, &ctx->initiate, sizeof(ctx->initiate));
399 	if (IS_ERR(p))
400 		goto out_err;
401 
402 	/* Old format supports only DES!  Any other enctype uses new format */
403 	ctx->enctype = ENCTYPE_DES_CBC_RAW;
404 
405 	ctx->gk5e = gss_krb5_lookup_enctype(ctx->enctype);
406 	if (ctx->gk5e == NULL) {
407 		p = ERR_PTR(-EINVAL);
408 		goto out_err;
409 	}
410 
411 	/* The downcall format was designed before we completely understood
412 	 * the uses of the context fields; so it includes some stuff we
413 	 * just give some minimal sanity-checking, and some we ignore
414 	 * completely (like the next twenty bytes): */
415 	if (unlikely(p + 20 > end || p + 20 < p)) {
416 		p = ERR_PTR(-EFAULT);
417 		goto out_err;
418 	}
419 	p += 20;
420 	p = simple_get_bytes(p, end, &tmp, sizeof(tmp));
421 	if (IS_ERR(p))
422 		goto out_err;
423 	if (tmp != SGN_ALG_DES_MAC_MD5) {
424 		p = ERR_PTR(-ENOSYS);
425 		goto out_err;
426 	}
427 	p = simple_get_bytes(p, end, &tmp, sizeof(tmp));
428 	if (IS_ERR(p))
429 		goto out_err;
430 	if (tmp != SEAL_ALG_DES) {
431 		p = ERR_PTR(-ENOSYS);
432 		goto out_err;
433 	}
434 	p = simple_get_bytes(p, end, &time32, sizeof(time32));
435 	if (IS_ERR(p))
436 		goto out_err;
437 	/* unsigned 32-bit time overflows in year 2106 */
438 	ctx->endtime = (time64_t)time32;
439 	p = simple_get_bytes(p, end, &seq_send, sizeof(seq_send));
440 	if (IS_ERR(p))
441 		goto out_err;
442 	atomic_set(&ctx->seq_send, seq_send);
443 	p = simple_get_netobj(p, end, &ctx->mech_used);
444 	if (IS_ERR(p))
445 		goto out_err;
446 	p = get_key(p, end, ctx, &ctx->enc);
447 	if (IS_ERR(p))
448 		goto out_err_free_mech;
449 	p = get_key(p, end, ctx, &ctx->seq);
450 	if (IS_ERR(p))
451 		goto out_err_free_key1;
452 	if (p != end) {
453 		p = ERR_PTR(-EFAULT);
454 		goto out_err_free_key2;
455 	}
456 
457 	return 0;
458 
459 out_err_free_key2:
460 	crypto_free_sync_skcipher(ctx->seq);
461 out_err_free_key1:
462 	crypto_free_sync_skcipher(ctx->enc);
463 out_err_free_mech:
464 	kfree(ctx->mech_used.data);
465 out_err:
466 	return PTR_ERR(p);
467 }
468 
469 #if defined(CONFIG_RPCSEC_GSS_KRB5_SIMPLIFIED)
470 static int
471 gss_krb5_import_ctx_des(struct krb5_ctx *ctx, gfp_t gfp_mask)
472 {
473 	return -EINVAL;
474 }
475 
476 static int
477 gss_krb5_import_ctx_v1(struct krb5_ctx *ctx, gfp_t gfp_mask)
478 {
479 	struct xdr_netobj keyin, keyout;
480 
481 	keyin.data = ctx->Ksess;
482 	keyin.len = ctx->gk5e->keylength;
483 
484 	ctx->seq = gss_krb5_alloc_cipher_v1(ctx, &keyin);
485 	if (ctx->seq == NULL)
486 		goto out_err;
487 	ctx->enc = gss_krb5_alloc_cipher_v1(ctx, &keyin);
488 	if (ctx->enc == NULL)
489 		goto out_free_seq;
490 
491 	/* derive cksum */
492 	keyout.data = ctx->cksum;
493 	keyout.len = ctx->gk5e->keylength;
494 	if (krb5_derive_key(ctx, &keyin, &keyout, KG_USAGE_SIGN,
495 			    KEY_USAGE_SEED_CHECKSUM, gfp_mask))
496 		goto out_free_enc;
497 
498 	return 0;
499 
500 out_free_enc:
501 	crypto_free_sync_skcipher(ctx->enc);
502 out_free_seq:
503 	crypto_free_sync_skcipher(ctx->seq);
504 out_err:
505 	return -EINVAL;
506 }
507 #endif
508 
509 #if defined(CONFIG_RPCSEC_GSS_KRB5_CRYPTOSYSTEM)
510 
511 static struct crypto_sync_skcipher *
512 gss_krb5_alloc_cipher_v2(const char *cname, const struct xdr_netobj *key)
513 {
514 	struct crypto_sync_skcipher *tfm;
515 
516 	tfm = crypto_alloc_sync_skcipher(cname, 0, 0);
517 	if (IS_ERR(tfm))
518 		return NULL;
519 	if (crypto_sync_skcipher_setkey(tfm, key->data, key->len)) {
520 		crypto_free_sync_skcipher(tfm);
521 		return NULL;
522 	}
523 	return tfm;
524 }
525 
526 static struct crypto_ahash *
527 gss_krb5_alloc_hash_v2(struct krb5_ctx *kctx, const struct xdr_netobj *key)
528 {
529 	struct crypto_ahash *tfm;
530 
531 	tfm = crypto_alloc_ahash(kctx->gk5e->cksum_name, 0, CRYPTO_ALG_ASYNC);
532 	if (IS_ERR(tfm))
533 		return NULL;
534 	if (crypto_ahash_setkey(tfm, key->data, key->len)) {
535 		crypto_free_ahash(tfm);
536 		return NULL;
537 	}
538 	return tfm;
539 }
540 
541 static int
542 gss_krb5_import_ctx_v2(struct krb5_ctx *ctx, gfp_t gfp_mask)
543 {
544 	struct xdr_netobj keyin = {
545 		.len	= ctx->gk5e->keylength,
546 		.data	= ctx->Ksess,
547 	};
548 	struct xdr_netobj keyout;
549 	int ret = -EINVAL;
550 
551 	keyout.data = kmalloc(GSS_KRB5_MAX_KEYLEN, gfp_mask);
552 	if (!keyout.data)
553 		return -ENOMEM;
554 
555 	/* initiator seal encryption */
556 	keyout.len = ctx->gk5e->Ke_length;
557 	if (krb5_derive_key(ctx, &keyin, &keyout, KG_USAGE_INITIATOR_SEAL,
558 			    KEY_USAGE_SEED_ENCRYPTION, gfp_mask))
559 		goto out;
560 	ctx->initiator_enc = gss_krb5_alloc_cipher_v2(ctx->gk5e->encrypt_name,
561 						      &keyout);
562 	if (ctx->initiator_enc == NULL)
563 		goto out;
564 	if (ctx->gk5e->aux_cipher) {
565 		ctx->initiator_enc_aux =
566 			gss_krb5_alloc_cipher_v2(ctx->gk5e->aux_cipher,
567 						 &keyout);
568 		if (ctx->initiator_enc_aux == NULL)
569 			goto out_free;
570 	}
571 
572 	/* acceptor seal encryption */
573 	if (krb5_derive_key(ctx, &keyin, &keyout, KG_USAGE_ACCEPTOR_SEAL,
574 			    KEY_USAGE_SEED_ENCRYPTION, gfp_mask))
575 		goto out_free;
576 	ctx->acceptor_enc = gss_krb5_alloc_cipher_v2(ctx->gk5e->encrypt_name,
577 						     &keyout);
578 	if (ctx->acceptor_enc == NULL)
579 		goto out_free;
580 	if (ctx->gk5e->aux_cipher) {
581 		ctx->acceptor_enc_aux =
582 			gss_krb5_alloc_cipher_v2(ctx->gk5e->aux_cipher,
583 						 &keyout);
584 		if (ctx->acceptor_enc_aux == NULL)
585 			goto out_free;
586 	}
587 
588 	/* initiator sign checksum */
589 	keyout.len = ctx->gk5e->Kc_length;
590 	if (krb5_derive_key(ctx, &keyin, &keyout, KG_USAGE_INITIATOR_SIGN,
591 			    KEY_USAGE_SEED_CHECKSUM, gfp_mask))
592 		goto out_free;
593 	ctx->initiator_sign = gss_krb5_alloc_hash_v2(ctx, &keyout);
594 	if (ctx->initiator_sign == NULL)
595 		goto out_free;
596 
597 	/* acceptor sign checksum */
598 	if (krb5_derive_key(ctx, &keyin, &keyout, KG_USAGE_ACCEPTOR_SIGN,
599 			    KEY_USAGE_SEED_CHECKSUM, gfp_mask))
600 		goto out_free;
601 	ctx->acceptor_sign = gss_krb5_alloc_hash_v2(ctx, &keyout);
602 	if (ctx->acceptor_sign == NULL)
603 		goto out_free;
604 
605 	/* initiator seal integrity */
606 	keyout.len = ctx->gk5e->Ki_length;
607 	if (krb5_derive_key(ctx, &keyin, &keyout, KG_USAGE_INITIATOR_SEAL,
608 			    KEY_USAGE_SEED_INTEGRITY, gfp_mask))
609 		goto out_free;
610 	ctx->initiator_integ = gss_krb5_alloc_hash_v2(ctx, &keyout);
611 	if (ctx->initiator_integ == NULL)
612 		goto out_free;
613 
614 	/* acceptor seal integrity */
615 	if (krb5_derive_key(ctx, &keyin, &keyout, KG_USAGE_ACCEPTOR_SEAL,
616 			    KEY_USAGE_SEED_INTEGRITY, gfp_mask))
617 		goto out_free;
618 	ctx->acceptor_integ = gss_krb5_alloc_hash_v2(ctx, &keyout);
619 	if (ctx->acceptor_integ == NULL)
620 		goto out_free;
621 
622 	ret = 0;
623 out:
624 	kfree_sensitive(keyout.data);
625 	return ret;
626 
627 out_free:
628 	crypto_free_ahash(ctx->acceptor_integ);
629 	crypto_free_ahash(ctx->initiator_integ);
630 	crypto_free_ahash(ctx->acceptor_sign);
631 	crypto_free_ahash(ctx->initiator_sign);
632 	crypto_free_sync_skcipher(ctx->acceptor_enc_aux);
633 	crypto_free_sync_skcipher(ctx->acceptor_enc);
634 	crypto_free_sync_skcipher(ctx->initiator_enc_aux);
635 	crypto_free_sync_skcipher(ctx->initiator_enc);
636 	goto out;
637 }
638 
639 #endif
640 
641 static int
642 gss_import_v2_context(const void *p, const void *end, struct krb5_ctx *ctx,
643 		gfp_t gfp_mask)
644 {
645 	u64 seq_send64;
646 	int keylen;
647 	u32 time32;
648 
649 	p = simple_get_bytes(p, end, &ctx->flags, sizeof(ctx->flags));
650 	if (IS_ERR(p))
651 		goto out_err;
652 	ctx->initiate = ctx->flags & KRB5_CTX_FLAG_INITIATOR;
653 
654 	p = simple_get_bytes(p, end, &time32, sizeof(time32));
655 	if (IS_ERR(p))
656 		goto out_err;
657 	/* unsigned 32-bit time overflows in year 2106 */
658 	ctx->endtime = (time64_t)time32;
659 	p = simple_get_bytes(p, end, &seq_send64, sizeof(seq_send64));
660 	if (IS_ERR(p))
661 		goto out_err;
662 	atomic64_set(&ctx->seq_send64, seq_send64);
663 	/* set seq_send for use by "older" enctypes */
664 	atomic_set(&ctx->seq_send, seq_send64);
665 	if (seq_send64 != atomic_read(&ctx->seq_send)) {
666 		dprintk("%s: seq_send64 %llx, seq_send %x overflow?\n", __func__,
667 			seq_send64, atomic_read(&ctx->seq_send));
668 		p = ERR_PTR(-EINVAL);
669 		goto out_err;
670 	}
671 	p = simple_get_bytes(p, end, &ctx->enctype, sizeof(ctx->enctype));
672 	if (IS_ERR(p))
673 		goto out_err;
674 	/* Map ENCTYPE_DES3_CBC_SHA1 to ENCTYPE_DES3_CBC_RAW */
675 	if (ctx->enctype == ENCTYPE_DES3_CBC_SHA1)
676 		ctx->enctype = ENCTYPE_DES3_CBC_RAW;
677 	ctx->gk5e = gss_krb5_lookup_enctype(ctx->enctype);
678 	if (ctx->gk5e == NULL) {
679 		dprintk("gss_kerberos_mech: unsupported krb5 enctype %u\n",
680 			ctx->enctype);
681 		p = ERR_PTR(-EINVAL);
682 		goto out_err;
683 	}
684 	keylen = ctx->gk5e->keylength;
685 
686 	p = simple_get_bytes(p, end, ctx->Ksess, keylen);
687 	if (IS_ERR(p))
688 		goto out_err;
689 
690 	if (p != end) {
691 		p = ERR_PTR(-EINVAL);
692 		goto out_err;
693 	}
694 
695 	ctx->mech_used.data = kmemdup(gss_kerberos_mech.gm_oid.data,
696 				      gss_kerberos_mech.gm_oid.len, gfp_mask);
697 	if (unlikely(ctx->mech_used.data == NULL)) {
698 		p = ERR_PTR(-ENOMEM);
699 		goto out_err;
700 	}
701 	ctx->mech_used.len = gss_kerberos_mech.gm_oid.len;
702 
703 	return ctx->gk5e->import_ctx(ctx, gfp_mask);
704 
705 out_err:
706 	return PTR_ERR(p);
707 }
708 
709 static int
710 gss_krb5_import_sec_context(const void *p, size_t len, struct gss_ctx *ctx_id,
711 			    time64_t *endtime, gfp_t gfp_mask)
712 {
713 	const void *end = (const void *)((const char *)p + len);
714 	struct  krb5_ctx *ctx;
715 	int ret;
716 
717 	ctx = kzalloc(sizeof(*ctx), gfp_mask);
718 	if (ctx == NULL)
719 		return -ENOMEM;
720 
721 	if (len == 85)
722 		ret = gss_import_v1_context(p, end, ctx);
723 	else
724 		ret = gss_import_v2_context(p, end, ctx, gfp_mask);
725 	memzero_explicit(&ctx->Ksess, sizeof(ctx->Ksess));
726 	if (ret) {
727 		kfree(ctx);
728 		return ret;
729 	}
730 
731 	ctx_id->internal_ctx_id = ctx;
732 	if (endtime)
733 		*endtime = ctx->endtime;
734 	return 0;
735 }
736 
737 static void
738 gss_krb5_delete_sec_context(void *internal_ctx)
739 {
740 	struct krb5_ctx *kctx = internal_ctx;
741 
742 	crypto_free_sync_skcipher(kctx->seq);
743 	crypto_free_sync_skcipher(kctx->enc);
744 	crypto_free_sync_skcipher(kctx->acceptor_enc);
745 	crypto_free_sync_skcipher(kctx->initiator_enc);
746 	crypto_free_sync_skcipher(kctx->acceptor_enc_aux);
747 	crypto_free_sync_skcipher(kctx->initiator_enc_aux);
748 	crypto_free_ahash(kctx->acceptor_sign);
749 	crypto_free_ahash(kctx->initiator_sign);
750 	crypto_free_ahash(kctx->acceptor_integ);
751 	crypto_free_ahash(kctx->initiator_integ);
752 	kfree(kctx->mech_used.data);
753 	kfree(kctx);
754 }
755 
756 /**
757  * gss_krb5_get_mic - get_mic for the Kerberos GSS mechanism
758  * @gctx: GSS context
759  * @text: plaintext to checksum
760  * @token: buffer into which to write the computed checksum
761  *
762  * Return values:
763  *    %GSS_S_COMPLETE - success, and @token is filled in
764  *    %GSS_S_FAILURE - checksum could not be generated
765  *    %GSS_S_CONTEXT_EXPIRED - Kerberos context is no longer valid
766  */
767 static u32 gss_krb5_get_mic(struct gss_ctx *gctx, struct xdr_buf *text,
768 			    struct xdr_netobj *token)
769 {
770 	struct krb5_ctx *kctx = gctx->internal_ctx_id;
771 
772 	return kctx->gk5e->get_mic(kctx, text, token);
773 }
774 
775 /**
776  * gss_krb5_verify_mic - verify_mic for the Kerberos GSS mechanism
777  * @gctx: GSS context
778  * @message_buffer: plaintext to check
779  * @read_token: received checksum to check
780  *
781  * Return values:
782  *    %GSS_S_COMPLETE - computed and received checksums match
783  *    %GSS_S_DEFECTIVE_TOKEN - received checksum is not valid
784  *    %GSS_S_BAD_SIG - computed and received checksums do not match
785  *    %GSS_S_FAILURE - received checksum could not be checked
786  *    %GSS_S_CONTEXT_EXPIRED - Kerberos context is no longer valid
787  */
788 static u32 gss_krb5_verify_mic(struct gss_ctx *gctx,
789 			       struct xdr_buf *message_buffer,
790 			       struct xdr_netobj *read_token)
791 {
792 	struct krb5_ctx *kctx = gctx->internal_ctx_id;
793 
794 	return kctx->gk5e->verify_mic(kctx, message_buffer, read_token);
795 }
796 
797 /**
798  * gss_krb5_wrap - gss_wrap for the Kerberos GSS mechanism
799  * @gctx: initialized GSS context
800  * @offset: byte offset in @buf to start writing the cipher text
801  * @buf: OUT: send buffer
802  * @pages: plaintext to wrap
803  *
804  * Return values:
805  *    %GSS_S_COMPLETE - success, @buf has been updated
806  *    %GSS_S_FAILURE - @buf could not be wrapped
807  *    %GSS_S_CONTEXT_EXPIRED - Kerberos context is no longer valid
808  */
809 static u32 gss_krb5_wrap(struct gss_ctx *gctx, int offset,
810 			 struct xdr_buf *buf, struct page **pages)
811 {
812 	struct krb5_ctx	*kctx = gctx->internal_ctx_id;
813 
814 	return kctx->gk5e->wrap(kctx, offset, buf, pages);
815 }
816 
817 /**
818  * gss_krb5_unwrap - gss_unwrap for the Kerberos GSS mechanism
819  * @gctx: initialized GSS context
820  * @offset: starting byte offset into @buf
821  * @len: size of ciphertext to unwrap
822  * @buf: ciphertext to unwrap
823  *
824  * Return values:
825  *    %GSS_S_COMPLETE - success, @buf has been updated
826  *    %GSS_S_DEFECTIVE_TOKEN - received blob is not valid
827  *    %GSS_S_BAD_SIG - computed and received checksums do not match
828  *    %GSS_S_FAILURE - @buf could not be unwrapped
829  *    %GSS_S_CONTEXT_EXPIRED - Kerberos context is no longer valid
830  */
831 static u32 gss_krb5_unwrap(struct gss_ctx *gctx, int offset,
832 			   int len, struct xdr_buf *buf)
833 {
834 	struct krb5_ctx	*kctx = gctx->internal_ctx_id;
835 
836 	return kctx->gk5e->unwrap(kctx, offset, len, buf,
837 				  &gctx->slack, &gctx->align);
838 }
839 
840 static const struct gss_api_ops gss_kerberos_ops = {
841 	.gss_import_sec_context	= gss_krb5_import_sec_context,
842 	.gss_get_mic		= gss_krb5_get_mic,
843 	.gss_verify_mic		= gss_krb5_verify_mic,
844 	.gss_wrap		= gss_krb5_wrap,
845 	.gss_unwrap		= gss_krb5_unwrap,
846 	.gss_delete_sec_context	= gss_krb5_delete_sec_context,
847 };
848 
849 static struct pf_desc gss_kerberos_pfs[] = {
850 	[0] = {
851 		.pseudoflavor = RPC_AUTH_GSS_KRB5,
852 		.qop = GSS_C_QOP_DEFAULT,
853 		.service = RPC_GSS_SVC_NONE,
854 		.name = "krb5",
855 	},
856 	[1] = {
857 		.pseudoflavor = RPC_AUTH_GSS_KRB5I,
858 		.qop = GSS_C_QOP_DEFAULT,
859 		.service = RPC_GSS_SVC_INTEGRITY,
860 		.name = "krb5i",
861 		.datatouch = true,
862 	},
863 	[2] = {
864 		.pseudoflavor = RPC_AUTH_GSS_KRB5P,
865 		.qop = GSS_C_QOP_DEFAULT,
866 		.service = RPC_GSS_SVC_PRIVACY,
867 		.name = "krb5p",
868 		.datatouch = true,
869 	},
870 };
871 
872 MODULE_ALIAS("rpc-auth-gss-krb5");
873 MODULE_ALIAS("rpc-auth-gss-krb5i");
874 MODULE_ALIAS("rpc-auth-gss-krb5p");
875 MODULE_ALIAS("rpc-auth-gss-390003");
876 MODULE_ALIAS("rpc-auth-gss-390004");
877 MODULE_ALIAS("rpc-auth-gss-390005");
878 MODULE_ALIAS("rpc-auth-gss-1.2.840.113554.1.2.2");
879 
880 static struct gss_api_mech gss_kerberos_mech = {
881 	.gm_name	= "krb5",
882 	.gm_owner	= THIS_MODULE,
883 	.gm_oid		= { 9, "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02" },
884 	.gm_ops		= &gss_kerberos_ops,
885 	.gm_pf_num	= ARRAY_SIZE(gss_kerberos_pfs),
886 	.gm_pfs		= gss_kerberos_pfs,
887 	.gm_upcall_enctypes = gss_krb5_enctype_priority_list,
888 };
889 
890 static int __init init_kerberos_module(void)
891 {
892 	int status;
893 
894 	gss_krb5_prepare_enctype_priority_list();
895 	status = gss_mech_register(&gss_kerberos_mech);
896 	if (status)
897 		printk("Failed to register kerberos gss mechanism!\n");
898 	return status;
899 }
900 
901 static void __exit cleanup_kerberos_module(void)
902 {
903 	gss_mech_unregister(&gss_kerberos_mech);
904 }
905 
906 MODULE_LICENSE("GPL");
907 module_init(init_kerberos_module);
908 module_exit(cleanup_kerberos_module);
909