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