Commit | Line | Data |
---|---|---|
28db8e3e MH |
1 | /* |
2 | * GCM: Galois/Counter Mode. | |
3 | * | |
4 | * Copyright (c) 2007 Nokia Siemens Networks - Mikko Herranen <mh1@iki.fi> | |
5 | * | |
6 | * This program is free software; you can redistribute it and/or modify it | |
7 | * under the terms of the GNU General Public License version 2 as published | |
8 | * by the Free Software Foundation. | |
9 | */ | |
10 | ||
11 | #include <crypto/algapi.h> | |
12 | #include <crypto/gf128mul.h> | |
42c271c6 | 13 | #include <crypto/scatterwalk.h> |
28db8e3e MH |
14 | #include <linux/err.h> |
15 | #include <linux/init.h> | |
16 | #include <linux/kernel.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/slab.h> | |
19 | ||
42c271c6 | 20 | #include "internal.h" |
28db8e3e MH |
21 | |
22 | struct gcm_instance_ctx { | |
23 | struct crypto_spawn ctr; | |
24 | }; | |
25 | ||
26 | struct crypto_gcm_ctx { | |
27 | struct crypto_ablkcipher *ctr; | |
28 | struct gf128mul_4k *gf128; | |
29 | }; | |
30 | ||
31 | struct crypto_gcm_ghash_ctx { | |
32 | u32 bytes; | |
33 | u32 flags; | |
34 | struct gf128mul_4k *gf128; | |
35 | u8 buffer[16]; | |
36 | }; | |
37 | ||
38 | struct crypto_gcm_req_priv_ctx { | |
39 | u8 auth_tag[16]; | |
6160b289 | 40 | u8 iauth_tag[16]; |
28db8e3e MH |
41 | u8 counter[16]; |
42 | struct crypto_gcm_ghash_ctx ghash; | |
7f681378 | 43 | struct ablkcipher_request abreq; |
28db8e3e MH |
44 | }; |
45 | ||
46 | static void crypto_gcm_ghash_init(struct crypto_gcm_ghash_ctx *ctx, u32 flags, | |
47 | struct gf128mul_4k *gf128) | |
48 | { | |
49 | ctx->bytes = 0; | |
50 | ctx->flags = flags; | |
51 | ctx->gf128 = gf128; | |
52 | memset(ctx->buffer, 0, 16); | |
53 | } | |
54 | ||
55 | static void crypto_gcm_ghash_update(struct crypto_gcm_ghash_ctx *ctx, | |
56 | const u8 *src, unsigned int srclen) | |
57 | { | |
58 | u8 *dst = ctx->buffer; | |
59 | ||
60 | if (ctx->bytes) { | |
61 | int n = min(srclen, ctx->bytes); | |
62 | u8 *pos = dst + (16 - ctx->bytes); | |
63 | ||
64 | ctx->bytes -= n; | |
65 | srclen -= n; | |
66 | ||
67 | while (n--) | |
68 | *pos++ ^= *src++; | |
69 | ||
70 | if (!ctx->bytes) | |
71 | gf128mul_4k_lle((be128 *)dst, ctx->gf128); | |
72 | } | |
73 | ||
74 | while (srclen >= 16) { | |
75 | crypto_xor(dst, src, 16); | |
76 | gf128mul_4k_lle((be128 *)dst, ctx->gf128); | |
77 | src += 16; | |
78 | srclen -= 16; | |
79 | } | |
80 | ||
81 | if (srclen) { | |
82 | ctx->bytes = 16 - srclen; | |
83 | while (srclen--) | |
84 | *dst++ ^= *src++; | |
85 | } | |
86 | } | |
87 | ||
88 | static void crypto_gcm_ghash_update_sg(struct crypto_gcm_ghash_ctx *ctx, | |
89 | struct scatterlist *sg, int len) | |
90 | { | |
91 | struct scatter_walk walk; | |
92 | u8 *src; | |
93 | int n; | |
94 | ||
6160b289 HX |
95 | if (!len) |
96 | return; | |
97 | ||
28db8e3e MH |
98 | scatterwalk_start(&walk, sg); |
99 | ||
100 | while (len) { | |
101 | n = scatterwalk_clamp(&walk, len); | |
102 | ||
103 | if (!n) { | |
b2ab4a57 | 104 | scatterwalk_start(&walk, scatterwalk_sg_next(walk.sg)); |
28db8e3e MH |
105 | n = scatterwalk_clamp(&walk, len); |
106 | } | |
107 | ||
108 | src = scatterwalk_map(&walk, 0); | |
109 | ||
110 | crypto_gcm_ghash_update(ctx, src, n); | |
111 | len -= n; | |
112 | ||
113 | scatterwalk_unmap(src, 0); | |
114 | scatterwalk_advance(&walk, n); | |
115 | scatterwalk_done(&walk, 0, len); | |
116 | if (len) | |
117 | crypto_yield(ctx->flags); | |
118 | } | |
119 | } | |
120 | ||
121 | static void crypto_gcm_ghash_flush(struct crypto_gcm_ghash_ctx *ctx) | |
122 | { | |
123 | u8 *dst = ctx->buffer; | |
124 | ||
125 | if (ctx->bytes) { | |
126 | u8 *tmp = dst + (16 - ctx->bytes); | |
127 | ||
128 | while (ctx->bytes--) | |
129 | *tmp++ ^= 0; | |
130 | ||
131 | gf128mul_4k_lle((be128 *)dst, ctx->gf128); | |
132 | } | |
133 | ||
134 | ctx->bytes = 0; | |
135 | } | |
136 | ||
137 | static void crypto_gcm_ghash_final_xor(struct crypto_gcm_ghash_ctx *ctx, | |
138 | unsigned int authlen, | |
139 | unsigned int cryptlen, u8 *dst) | |
140 | { | |
141 | u8 *buf = ctx->buffer; | |
142 | u128 lengths; | |
143 | ||
144 | lengths.a = cpu_to_be64(authlen * 8); | |
145 | lengths.b = cpu_to_be64(cryptlen * 8); | |
146 | ||
147 | crypto_gcm_ghash_flush(ctx); | |
148 | crypto_xor(buf, (u8 *)&lengths, 16); | |
149 | gf128mul_4k_lle((be128 *)buf, ctx->gf128); | |
150 | crypto_xor(dst, buf, 16); | |
151 | } | |
152 | ||
153 | static inline void crypto_gcm_set_counter(u8 *counterblock, u32 value) | |
154 | { | |
155 | *((u32 *)&counterblock[12]) = cpu_to_be32(value); | |
156 | } | |
157 | ||
158 | static int crypto_gcm_encrypt_counter(struct crypto_aead *aead, u8 *block, | |
159 | u32 value, const u8 *iv) | |
160 | { | |
161 | struct crypto_gcm_ctx *ctx = crypto_aead_ctx(aead); | |
162 | struct crypto_ablkcipher *ctr = ctx->ctr; | |
163 | struct ablkcipher_request req; | |
164 | struct scatterlist sg; | |
165 | u8 counterblock[16]; | |
166 | ||
167 | if (iv == NULL) | |
168 | memset(counterblock, 0, 12); | |
169 | else | |
170 | memcpy(counterblock, iv, 12); | |
171 | ||
172 | crypto_gcm_set_counter(counterblock, value); | |
173 | ||
174 | sg_init_one(&sg, block, 16); | |
175 | ablkcipher_request_set_tfm(&req, ctr); | |
176 | ablkcipher_request_set_crypt(&req, &sg, &sg, 16, counterblock); | |
177 | ablkcipher_request_set_callback(&req, 0, NULL, NULL); | |
178 | memset(block, 0, 16); | |
179 | return crypto_ablkcipher_encrypt(&req); | |
180 | } | |
181 | ||
182 | static int crypto_gcm_setkey(struct crypto_aead *aead, const u8 *key, | |
183 | unsigned int keylen) | |
184 | { | |
185 | struct crypto_gcm_ctx *ctx = crypto_aead_ctx(aead); | |
186 | struct crypto_ablkcipher *ctr = ctx->ctr; | |
187 | int alignmask = crypto_ablkcipher_alignmask(ctr); | |
188 | u8 alignbuf[16+alignmask]; | |
189 | u8 *hash = (u8 *)ALIGN((unsigned long)alignbuf, alignmask+1); | |
190 | int err = 0; | |
191 | ||
192 | crypto_ablkcipher_clear_flags(ctr, CRYPTO_TFM_REQ_MASK); | |
193 | crypto_ablkcipher_set_flags(ctr, crypto_aead_get_flags(aead) & | |
194 | CRYPTO_TFM_REQ_MASK); | |
195 | ||
196 | err = crypto_ablkcipher_setkey(ctr, key, keylen); | |
197 | if (err) | |
198 | goto out; | |
199 | ||
200 | crypto_aead_set_flags(aead, crypto_ablkcipher_get_flags(ctr) & | |
201 | CRYPTO_TFM_RES_MASK); | |
202 | ||
203 | err = crypto_gcm_encrypt_counter(aead, hash, -1, NULL); | |
204 | if (err) | |
205 | goto out; | |
206 | ||
207 | if (ctx->gf128 != NULL) | |
208 | gf128mul_free_4k(ctx->gf128); | |
209 | ||
210 | ctx->gf128 = gf128mul_init_4k_lle((be128 *)hash); | |
211 | ||
212 | if (ctx->gf128 == NULL) | |
213 | err = -ENOMEM; | |
214 | ||
215 | out: | |
216 | return err; | |
217 | } | |
218 | ||
219 | static int crypto_gcm_init_crypt(struct ablkcipher_request *ablk_req, | |
6160b289 HX |
220 | struct aead_request *req, |
221 | unsigned int cryptlen, | |
222 | void (*done)(struct crypto_async_request *, | |
223 | int)) | |
28db8e3e MH |
224 | { |
225 | struct crypto_aead *aead = crypto_aead_reqtfm(req); | |
226 | struct crypto_gcm_ctx *ctx = crypto_aead_ctx(aead); | |
227 | struct crypto_gcm_req_priv_ctx *pctx = aead_request_ctx(req); | |
228 | u32 flags = req->base.tfm->crt_flags; | |
229 | u8 *auth_tag = pctx->auth_tag; | |
230 | u8 *counter = pctx->counter; | |
231 | struct crypto_gcm_ghash_ctx *ghash = &pctx->ghash; | |
232 | int err = 0; | |
233 | ||
234 | ablkcipher_request_set_tfm(ablk_req, ctx->ctr); | |
235 | ablkcipher_request_set_callback(ablk_req, aead_request_flags(req), | |
236 | done, req); | |
237 | ablkcipher_request_set_crypt(ablk_req, req->src, req->dst, | |
6160b289 | 238 | cryptlen, counter); |
28db8e3e MH |
239 | |
240 | err = crypto_gcm_encrypt_counter(aead, auth_tag, 0, req->iv); | |
241 | if (err) | |
242 | goto out; | |
243 | ||
244 | memcpy(counter, req->iv, 12); | |
245 | crypto_gcm_set_counter(counter, 1); | |
246 | ||
247 | crypto_gcm_ghash_init(ghash, flags, ctx->gf128); | |
248 | ||
6160b289 HX |
249 | crypto_gcm_ghash_update_sg(ghash, req->assoc, req->assoclen); |
250 | crypto_gcm_ghash_flush(ghash); | |
28db8e3e MH |
251 | |
252 | out: | |
253 | return err; | |
254 | } | |
255 | ||
6160b289 | 256 | static int crypto_gcm_hash(struct aead_request *req) |
28db8e3e | 257 | { |
6160b289 | 258 | struct crypto_aead *aead = crypto_aead_reqtfm(req); |
28db8e3e MH |
259 | struct crypto_gcm_req_priv_ctx *pctx = aead_request_ctx(req); |
260 | u8 *auth_tag = pctx->auth_tag; | |
261 | struct crypto_gcm_ghash_ctx *ghash = &pctx->ghash; | |
262 | ||
263 | crypto_gcm_ghash_update_sg(ghash, req->dst, req->cryptlen); | |
264 | crypto_gcm_ghash_final_xor(ghash, req->assoclen, req->cryptlen, | |
265 | auth_tag); | |
266 | ||
6160b289 HX |
267 | scatterwalk_map_and_copy(auth_tag, req->dst, req->cryptlen, |
268 | crypto_aead_authsize(aead), 1); | |
269 | return 0; | |
270 | } | |
271 | ||
272 | static void crypto_gcm_encrypt_done(struct crypto_async_request *areq, int err) | |
273 | { | |
274 | struct aead_request *req = areq->data; | |
275 | ||
276 | if (!err) | |
277 | err = crypto_gcm_hash(req); | |
278 | ||
28db8e3e MH |
279 | aead_request_complete(req, err); |
280 | } | |
281 | ||
282 | static int crypto_gcm_encrypt(struct aead_request *req) | |
283 | { | |
7f681378 HX |
284 | struct crypto_gcm_req_priv_ctx *pctx = aead_request_ctx(req); |
285 | struct ablkcipher_request *abreq = &pctx->abreq; | |
28db8e3e MH |
286 | int err = 0; |
287 | ||
7f681378 | 288 | err = crypto_gcm_init_crypt(abreq, req, req->cryptlen, |
6160b289 | 289 | crypto_gcm_encrypt_done); |
28db8e3e MH |
290 | if (err) |
291 | return err; | |
292 | ||
293 | if (req->cryptlen) { | |
7f681378 | 294 | err = crypto_ablkcipher_encrypt(abreq); |
28db8e3e MH |
295 | if (err) |
296 | return err; | |
28db8e3e MH |
297 | } |
298 | ||
6160b289 | 299 | return crypto_gcm_hash(req); |
28db8e3e MH |
300 | } |
301 | ||
302 | static void crypto_gcm_decrypt_done(struct crypto_async_request *areq, int err) | |
303 | { | |
304 | aead_request_complete(areq->data, err); | |
305 | } | |
306 | ||
307 | static int crypto_gcm_decrypt(struct aead_request *req) | |
308 | { | |
6160b289 | 309 | struct crypto_aead *aead = crypto_aead_reqtfm(req); |
28db8e3e | 310 | struct crypto_gcm_req_priv_ctx *pctx = aead_request_ctx(req); |
7f681378 | 311 | struct ablkcipher_request *abreq = &pctx->abreq; |
28db8e3e | 312 | u8 *auth_tag = pctx->auth_tag; |
6160b289 | 313 | u8 *iauth_tag = pctx->iauth_tag; |
28db8e3e | 314 | struct crypto_gcm_ghash_ctx *ghash = &pctx->ghash; |
6160b289 HX |
315 | unsigned int cryptlen = req->cryptlen; |
316 | unsigned int authsize = crypto_aead_authsize(aead); | |
28db8e3e MH |
317 | int err; |
318 | ||
6160b289 | 319 | if (cryptlen < authsize) |
28db8e3e | 320 | return -EINVAL; |
6160b289 | 321 | cryptlen -= authsize; |
28db8e3e | 322 | |
7f681378 | 323 | err = crypto_gcm_init_crypt(abreq, req, cryptlen, |
6160b289 | 324 | crypto_gcm_decrypt_done); |
28db8e3e MH |
325 | if (err) |
326 | return err; | |
327 | ||
6160b289 HX |
328 | crypto_gcm_ghash_update_sg(ghash, req->src, cryptlen); |
329 | crypto_gcm_ghash_final_xor(ghash, req->assoclen, cryptlen, auth_tag); | |
28db8e3e | 330 | |
6160b289 HX |
331 | scatterwalk_map_and_copy(iauth_tag, req->src, cryptlen, authsize, 0); |
332 | if (memcmp(iauth_tag, auth_tag, authsize)) | |
fe70f5df | 333 | return -EBADMSG; |
28db8e3e | 334 | |
7f681378 | 335 | return crypto_ablkcipher_decrypt(abreq); |
28db8e3e MH |
336 | } |
337 | ||
338 | static int crypto_gcm_init_tfm(struct crypto_tfm *tfm) | |
339 | { | |
340 | struct crypto_instance *inst = (void *)tfm->__crt_alg; | |
341 | struct gcm_instance_ctx *ictx = crypto_instance_ctx(inst); | |
342 | struct crypto_gcm_ctx *ctx = crypto_tfm_ctx(tfm); | |
343 | struct crypto_ablkcipher *ctr; | |
344 | unsigned long align; | |
345 | int err; | |
346 | ||
347 | ctr = crypto_spawn_ablkcipher(&ictx->ctr); | |
348 | err = PTR_ERR(ctr); | |
349 | if (IS_ERR(ctr)) | |
350 | return err; | |
351 | ||
352 | ctx->ctr = ctr; | |
353 | ctx->gf128 = NULL; | |
354 | ||
355 | align = max_t(unsigned long, crypto_ablkcipher_alignmask(ctr), | |
356 | __alignof__(u32) - 1); | |
357 | align &= ~(crypto_tfm_ctx_alignment() - 1); | |
7f681378 HX |
358 | tfm->crt_aead.reqsize = align + |
359 | sizeof(struct crypto_gcm_req_priv_ctx) + | |
360 | crypto_ablkcipher_reqsize(ctr); | |
28db8e3e MH |
361 | |
362 | return 0; | |
363 | } | |
364 | ||
365 | static void crypto_gcm_exit_tfm(struct crypto_tfm *tfm) | |
366 | { | |
367 | struct crypto_gcm_ctx *ctx = crypto_tfm_ctx(tfm); | |
368 | ||
369 | if (ctx->gf128 != NULL) | |
370 | gf128mul_free_4k(ctx->gf128); | |
371 | ||
372 | crypto_free_ablkcipher(ctx->ctr); | |
373 | } | |
374 | ||
375 | static struct crypto_instance *crypto_gcm_alloc(struct rtattr **tb) | |
376 | { | |
377 | struct crypto_instance *inst; | |
378 | struct crypto_alg *ctr; | |
379 | struct crypto_alg *cipher; | |
380 | struct gcm_instance_ctx *ctx; | |
381 | int err; | |
382 | char ctr_name[CRYPTO_MAX_ALG_NAME]; | |
383 | ||
384 | err = crypto_check_attr_type(tb, CRYPTO_ALG_TYPE_AEAD); | |
385 | if (err) | |
386 | return ERR_PTR(err); | |
387 | ||
388 | cipher = crypto_attr_alg(tb[1], CRYPTO_ALG_TYPE_CIPHER, | |
389 | CRYPTO_ALG_TYPE_MASK); | |
390 | ||
391 | inst = ERR_PTR(PTR_ERR(cipher)); | |
392 | if (IS_ERR(cipher)) | |
393 | return inst; | |
394 | ||
395 | inst = ERR_PTR(ENAMETOOLONG); | |
396 | if (snprintf( | |
397 | ctr_name, CRYPTO_MAX_ALG_NAME, | |
398 | "ctr(%s,0,16,4)", cipher->cra_name) >= CRYPTO_MAX_ALG_NAME) | |
399 | return inst; | |
400 | ||
401 | ctr = crypto_alg_mod_lookup(ctr_name, CRYPTO_ALG_TYPE_BLKCIPHER, | |
402 | CRYPTO_ALG_TYPE_MASK); | |
403 | ||
404 | if (IS_ERR(ctr)) | |
405 | return ERR_PTR(PTR_ERR(ctr)); | |
406 | ||
407 | if (cipher->cra_blocksize != 16) | |
408 | goto out_put_ctr; | |
409 | ||
410 | inst = kzalloc(sizeof(*inst) + sizeof(*ctx), GFP_KERNEL); | |
411 | err = -ENOMEM; | |
412 | if (!inst) | |
413 | goto out_put_ctr; | |
414 | ||
415 | err = -ENAMETOOLONG; | |
416 | if (snprintf(inst->alg.cra_name, CRYPTO_MAX_ALG_NAME, | |
417 | "gcm(%s)", cipher->cra_name) >= CRYPTO_MAX_ALG_NAME || | |
418 | snprintf(inst->alg.cra_driver_name, CRYPTO_MAX_ALG_NAME, | |
419 | "gcm(%s)", cipher->cra_driver_name) >= CRYPTO_MAX_ALG_NAME) | |
420 | goto err_free_inst; | |
421 | ||
422 | ||
423 | ctx = crypto_instance_ctx(inst); | |
424 | err = crypto_init_spawn(&ctx->ctr, ctr, inst, CRYPTO_ALG_TYPE_MASK); | |
425 | if (err) | |
426 | goto err_free_inst; | |
427 | ||
428 | inst->alg.cra_flags = CRYPTO_ALG_TYPE_AEAD | CRYPTO_ALG_ASYNC; | |
429 | inst->alg.cra_priority = ctr->cra_priority; | |
430 | inst->alg.cra_blocksize = 16; | |
431 | inst->alg.cra_alignmask = __alignof__(u32) - 1; | |
432 | inst->alg.cra_type = &crypto_aead_type; | |
433 | inst->alg.cra_aead.ivsize = 12; | |
7ba683a6 | 434 | inst->alg.cra_aead.maxauthsize = 16; |
28db8e3e MH |
435 | inst->alg.cra_ctxsize = sizeof(struct crypto_gcm_ctx); |
436 | inst->alg.cra_init = crypto_gcm_init_tfm; | |
437 | inst->alg.cra_exit = crypto_gcm_exit_tfm; | |
438 | inst->alg.cra_aead.setkey = crypto_gcm_setkey; | |
439 | inst->alg.cra_aead.encrypt = crypto_gcm_encrypt; | |
440 | inst->alg.cra_aead.decrypt = crypto_gcm_decrypt; | |
441 | ||
442 | out: | |
443 | crypto_mod_put(ctr); | |
444 | return inst; | |
445 | err_free_inst: | |
446 | kfree(inst); | |
447 | out_put_ctr: | |
448 | inst = ERR_PTR(err); | |
449 | goto out; | |
450 | } | |
451 | ||
452 | static void crypto_gcm_free(struct crypto_instance *inst) | |
453 | { | |
454 | struct gcm_instance_ctx *ctx = crypto_instance_ctx(inst); | |
455 | ||
456 | crypto_drop_spawn(&ctx->ctr); | |
457 | kfree(inst); | |
458 | } | |
459 | ||
460 | static struct crypto_template crypto_gcm_tmpl = { | |
461 | .name = "gcm", | |
462 | .alloc = crypto_gcm_alloc, | |
463 | .free = crypto_gcm_free, | |
464 | .module = THIS_MODULE, | |
465 | }; | |
466 | ||
467 | static int __init crypto_gcm_module_init(void) | |
468 | { | |
469 | return crypto_register_template(&crypto_gcm_tmpl); | |
470 | } | |
471 | ||
472 | static void __exit crypto_gcm_module_exit(void) | |
473 | { | |
474 | crypto_unregister_template(&crypto_gcm_tmpl); | |
475 | } | |
476 | ||
477 | module_init(crypto_gcm_module_init); | |
478 | module_exit(crypto_gcm_module_exit); | |
479 | ||
480 | MODULE_LICENSE("GPL"); | |
481 | MODULE_DESCRIPTION("Galois/Counter Mode"); | |
482 | MODULE_AUTHOR("Mikko Herranen <mh1@iki.fi>"); |