1 /* 2 * algif_hash: User-space interface for hash algorithms 3 * 4 * This file provides the user-space API for hash algorithms. 5 * 6 * Copyright (c) 2010 Herbert Xu <herbert@gondor.apana.org.au> 7 * 8 * This program is free software; you can redistribute it and/or modify it 9 * under the terms of the GNU General Public License as published by the Free 10 * Software Foundation; either version 2 of the License, or (at your option) 11 * any later version. 12 * 13 */ 14 15 #include <crypto/hash.h> 16 #include <crypto/if_alg.h> 17 #include <linux/init.h> 18 #include <linux/kernel.h> 19 #include <linux/mm.h> 20 #include <linux/module.h> 21 #include <linux/net.h> 22 #include <net/sock.h> 23 24 struct hash_ctx { 25 struct af_alg_sgl sgl; 26 27 u8 *result; 28 29 struct af_alg_completion completion; 30 31 unsigned int len; 32 bool more; 33 34 struct ahash_request req; 35 }; 36 37 struct algif_hash_tfm { 38 struct crypto_ahash *hash; 39 bool has_key; 40 }; 41 42 static int hash_alloc_result(struct sock *sk, struct hash_ctx *ctx) 43 { 44 unsigned ds; 45 46 if (ctx->result) 47 return 0; 48 49 ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req)); 50 51 ctx->result = sock_kmalloc(sk, ds, GFP_KERNEL); 52 if (!ctx->result) 53 return -ENOMEM; 54 55 memset(ctx->result, 0, ds); 56 57 return 0; 58 } 59 60 static void hash_free_result(struct sock *sk, struct hash_ctx *ctx) 61 { 62 unsigned ds; 63 64 if (!ctx->result) 65 return; 66 67 ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req)); 68 69 sock_kzfree_s(sk, ctx->result, ds); 70 ctx->result = NULL; 71 } 72 73 static int hash_sendmsg(struct socket *sock, struct msghdr *msg, 74 size_t ignored) 75 { 76 int limit = ALG_MAX_PAGES * PAGE_SIZE; 77 struct sock *sk = sock->sk; 78 struct alg_sock *ask = alg_sk(sk); 79 struct hash_ctx *ctx = ask->private; 80 long copied = 0; 81 int err; 82 83 if (limit > sk->sk_sndbuf) 84 limit = sk->sk_sndbuf; 85 86 lock_sock(sk); 87 if (!ctx->more) { 88 if ((msg->msg_flags & MSG_MORE)) 89 hash_free_result(sk, ctx); 90 91 err = af_alg_wait_for_completion(crypto_ahash_init(&ctx->req), 92 &ctx->completion); 93 if (err) 94 goto unlock; 95 } 96 97 ctx->more = 0; 98 99 while (msg_data_left(msg)) { 100 int len = msg_data_left(msg); 101 102 if (len > limit) 103 len = limit; 104 105 len = af_alg_make_sg(&ctx->sgl, &msg->msg_iter, len); 106 if (len < 0) { 107 err = copied ? 0 : len; 108 goto unlock; 109 } 110 111 ahash_request_set_crypt(&ctx->req, ctx->sgl.sg, NULL, len); 112 113 err = af_alg_wait_for_completion(crypto_ahash_update(&ctx->req), 114 &ctx->completion); 115 af_alg_free_sg(&ctx->sgl); 116 if (err) 117 goto unlock; 118 119 copied += len; 120 iov_iter_advance(&msg->msg_iter, len); 121 } 122 123 err = 0; 124 125 ctx->more = msg->msg_flags & MSG_MORE; 126 if (!ctx->more) { 127 err = hash_alloc_result(sk, ctx); 128 if (err) 129 goto unlock; 130 131 ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0); 132 err = af_alg_wait_for_completion(crypto_ahash_final(&ctx->req), 133 &ctx->completion); 134 } 135 136 unlock: 137 release_sock(sk); 138 139 return err ?: copied; 140 } 141 142 static ssize_t hash_sendpage(struct socket *sock, struct page *page, 143 int offset, size_t size, int flags) 144 { 145 struct sock *sk = sock->sk; 146 struct alg_sock *ask = alg_sk(sk); 147 struct hash_ctx *ctx = ask->private; 148 int err; 149 150 if (flags & MSG_SENDPAGE_NOTLAST) 151 flags |= MSG_MORE; 152 153 lock_sock(sk); 154 sg_init_table(ctx->sgl.sg, 1); 155 sg_set_page(ctx->sgl.sg, page, size, offset); 156 157 if (!(flags & MSG_MORE)) { 158 err = hash_alloc_result(sk, ctx); 159 if (err) 160 goto unlock; 161 } else if (!ctx->more) 162 hash_free_result(sk, ctx); 163 164 ahash_request_set_crypt(&ctx->req, ctx->sgl.sg, ctx->result, size); 165 166 if (!(flags & MSG_MORE)) { 167 if (ctx->more) 168 err = crypto_ahash_finup(&ctx->req); 169 else 170 err = crypto_ahash_digest(&ctx->req); 171 } else { 172 if (!ctx->more) { 173 err = crypto_ahash_init(&ctx->req); 174 err = af_alg_wait_for_completion(err, &ctx->completion); 175 if (err) 176 goto unlock; 177 } 178 179 err = crypto_ahash_update(&ctx->req); 180 } 181 182 err = af_alg_wait_for_completion(err, &ctx->completion); 183 if (err) 184 goto unlock; 185 186 ctx->more = flags & MSG_MORE; 187 188 unlock: 189 release_sock(sk); 190 191 return err ?: size; 192 } 193 194 static int hash_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, 195 int flags) 196 { 197 struct sock *sk = sock->sk; 198 struct alg_sock *ask = alg_sk(sk); 199 struct hash_ctx *ctx = ask->private; 200 unsigned ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req)); 201 bool result; 202 int err; 203 204 if (len > ds) 205 len = ds; 206 else if (len < ds) 207 msg->msg_flags |= MSG_TRUNC; 208 209 lock_sock(sk); 210 result = ctx->result; 211 err = hash_alloc_result(sk, ctx); 212 if (err) 213 goto unlock; 214 215 ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0); 216 217 if (!result && !ctx->more) { 218 err = af_alg_wait_for_completion( 219 crypto_ahash_init(&ctx->req), 220 &ctx->completion); 221 if (err) 222 goto unlock; 223 } 224 225 if (!result || ctx->more) { 226 ctx->more = 0; 227 err = af_alg_wait_for_completion(crypto_ahash_final(&ctx->req), 228 &ctx->completion); 229 if (err) 230 goto unlock; 231 } 232 233 err = memcpy_to_msg(msg, ctx->result, len); 234 235 unlock: 236 hash_free_result(sk, ctx); 237 release_sock(sk); 238 239 return err ?: len; 240 } 241 242 static int hash_accept(struct socket *sock, struct socket *newsock, int flags, 243 bool kern) 244 { 245 struct sock *sk = sock->sk; 246 struct alg_sock *ask = alg_sk(sk); 247 struct hash_ctx *ctx = ask->private; 248 struct ahash_request *req = &ctx->req; 249 char state[crypto_ahash_statesize(crypto_ahash_reqtfm(req)) ? : 1]; 250 struct sock *sk2; 251 struct alg_sock *ask2; 252 struct hash_ctx *ctx2; 253 bool more; 254 int err; 255 256 lock_sock(sk); 257 more = ctx->more; 258 err = more ? crypto_ahash_export(req, state) : 0; 259 release_sock(sk); 260 261 if (err) 262 return err; 263 264 err = af_alg_accept(ask->parent, newsock, kern); 265 if (err) 266 return err; 267 268 sk2 = newsock->sk; 269 ask2 = alg_sk(sk2); 270 ctx2 = ask2->private; 271 ctx2->more = more; 272 273 if (!more) 274 return err; 275 276 err = crypto_ahash_import(&ctx2->req, state); 277 if (err) { 278 sock_orphan(sk2); 279 sock_put(sk2); 280 } 281 282 return err; 283 } 284 285 static struct proto_ops algif_hash_ops = { 286 .family = PF_ALG, 287 288 .connect = sock_no_connect, 289 .socketpair = sock_no_socketpair, 290 .getname = sock_no_getname, 291 .ioctl = sock_no_ioctl, 292 .listen = sock_no_listen, 293 .shutdown = sock_no_shutdown, 294 .getsockopt = sock_no_getsockopt, 295 .mmap = sock_no_mmap, 296 .bind = sock_no_bind, 297 .setsockopt = sock_no_setsockopt, 298 .poll = sock_no_poll, 299 300 .release = af_alg_release, 301 .sendmsg = hash_sendmsg, 302 .sendpage = hash_sendpage, 303 .recvmsg = hash_recvmsg, 304 .accept = hash_accept, 305 }; 306 307 static int hash_check_key(struct socket *sock) 308 { 309 int err = 0; 310 struct sock *psk; 311 struct alg_sock *pask; 312 struct algif_hash_tfm *tfm; 313 struct sock *sk = sock->sk; 314 struct alg_sock *ask = alg_sk(sk); 315 316 lock_sock(sk); 317 if (ask->refcnt) 318 goto unlock_child; 319 320 psk = ask->parent; 321 pask = alg_sk(ask->parent); 322 tfm = pask->private; 323 324 err = -ENOKEY; 325 lock_sock_nested(psk, SINGLE_DEPTH_NESTING); 326 if (!tfm->has_key) 327 goto unlock; 328 329 if (!pask->refcnt++) 330 sock_hold(psk); 331 332 ask->refcnt = 1; 333 sock_put(psk); 334 335 err = 0; 336 337 unlock: 338 release_sock(psk); 339 unlock_child: 340 release_sock(sk); 341 342 return err; 343 } 344 345 static int hash_sendmsg_nokey(struct socket *sock, struct msghdr *msg, 346 size_t size) 347 { 348 int err; 349 350 err = hash_check_key(sock); 351 if (err) 352 return err; 353 354 return hash_sendmsg(sock, msg, size); 355 } 356 357 static ssize_t hash_sendpage_nokey(struct socket *sock, struct page *page, 358 int offset, size_t size, int flags) 359 { 360 int err; 361 362 err = hash_check_key(sock); 363 if (err) 364 return err; 365 366 return hash_sendpage(sock, page, offset, size, flags); 367 } 368 369 static int hash_recvmsg_nokey(struct socket *sock, struct msghdr *msg, 370 size_t ignored, int flags) 371 { 372 int err; 373 374 err = hash_check_key(sock); 375 if (err) 376 return err; 377 378 return hash_recvmsg(sock, msg, ignored, flags); 379 } 380 381 static int hash_accept_nokey(struct socket *sock, struct socket *newsock, 382 int flags, bool kern) 383 { 384 int err; 385 386 err = hash_check_key(sock); 387 if (err) 388 return err; 389 390 return hash_accept(sock, newsock, flags, kern); 391 } 392 393 static struct proto_ops algif_hash_ops_nokey = { 394 .family = PF_ALG, 395 396 .connect = sock_no_connect, 397 .socketpair = sock_no_socketpair, 398 .getname = sock_no_getname, 399 .ioctl = sock_no_ioctl, 400 .listen = sock_no_listen, 401 .shutdown = sock_no_shutdown, 402 .getsockopt = sock_no_getsockopt, 403 .mmap = sock_no_mmap, 404 .bind = sock_no_bind, 405 .setsockopt = sock_no_setsockopt, 406 .poll = sock_no_poll, 407 408 .release = af_alg_release, 409 .sendmsg = hash_sendmsg_nokey, 410 .sendpage = hash_sendpage_nokey, 411 .recvmsg = hash_recvmsg_nokey, 412 .accept = hash_accept_nokey, 413 }; 414 415 static void *hash_bind(const char *name, u32 type, u32 mask) 416 { 417 struct algif_hash_tfm *tfm; 418 struct crypto_ahash *hash; 419 420 tfm = kzalloc(sizeof(*tfm), GFP_KERNEL); 421 if (!tfm) 422 return ERR_PTR(-ENOMEM); 423 424 hash = crypto_alloc_ahash(name, type, mask); 425 if (IS_ERR(hash)) { 426 kfree(tfm); 427 return ERR_CAST(hash); 428 } 429 430 tfm->hash = hash; 431 432 return tfm; 433 } 434 435 static void hash_release(void *private) 436 { 437 struct algif_hash_tfm *tfm = private; 438 439 crypto_free_ahash(tfm->hash); 440 kfree(tfm); 441 } 442 443 static int hash_setkey(void *private, const u8 *key, unsigned int keylen) 444 { 445 struct algif_hash_tfm *tfm = private; 446 int err; 447 448 err = crypto_ahash_setkey(tfm->hash, key, keylen); 449 tfm->has_key = !err; 450 451 return err; 452 } 453 454 static void hash_sock_destruct(struct sock *sk) 455 { 456 struct alg_sock *ask = alg_sk(sk); 457 struct hash_ctx *ctx = ask->private; 458 459 hash_free_result(sk, ctx); 460 sock_kfree_s(sk, ctx, ctx->len); 461 af_alg_release_parent(sk); 462 } 463 464 static int hash_accept_parent_nokey(void *private, struct sock *sk) 465 { 466 struct hash_ctx *ctx; 467 struct alg_sock *ask = alg_sk(sk); 468 struct algif_hash_tfm *tfm = private; 469 struct crypto_ahash *hash = tfm->hash; 470 unsigned len = sizeof(*ctx) + crypto_ahash_reqsize(hash); 471 472 ctx = sock_kmalloc(sk, len, GFP_KERNEL); 473 if (!ctx) 474 return -ENOMEM; 475 476 ctx->result = NULL; 477 ctx->len = len; 478 ctx->more = 0; 479 af_alg_init_completion(&ctx->completion); 480 481 ask->private = ctx; 482 483 ahash_request_set_tfm(&ctx->req, hash); 484 ahash_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG, 485 af_alg_complete, &ctx->completion); 486 487 sk->sk_destruct = hash_sock_destruct; 488 489 return 0; 490 } 491 492 static int hash_accept_parent(void *private, struct sock *sk) 493 { 494 struct algif_hash_tfm *tfm = private; 495 496 if (!tfm->has_key && crypto_ahash_has_setkey(tfm->hash)) 497 return -ENOKEY; 498 499 return hash_accept_parent_nokey(private, sk); 500 } 501 502 static const struct af_alg_type algif_type_hash = { 503 .bind = hash_bind, 504 .release = hash_release, 505 .setkey = hash_setkey, 506 .accept = hash_accept_parent, 507 .accept_nokey = hash_accept_parent_nokey, 508 .ops = &algif_hash_ops, 509 .ops_nokey = &algif_hash_ops_nokey, 510 .name = "hash", 511 .owner = THIS_MODULE 512 }; 513 514 static int __init algif_hash_init(void) 515 { 516 return af_alg_register_type(&algif_type_hash); 517 } 518 519 static void __exit algif_hash_exit(void) 520 { 521 int err = af_alg_unregister_type(&algif_type_hash); 522 BUG_ON(err); 523 } 524 525 module_init(algif_hash_init); 526 module_exit(algif_hash_exit); 527 MODULE_LICENSE("GPL"); 528