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