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 crypto_wait wait; 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 = crypto_wait_req(crypto_ahash_init(&ctx->req), &ctx->wait); 92 if (err) 93 goto unlock; 94 } 95 96 ctx->more = 0; 97 98 while (msg_data_left(msg)) { 99 int len = msg_data_left(msg); 100 101 if (len > limit) 102 len = limit; 103 104 len = af_alg_make_sg(&ctx->sgl, &msg->msg_iter, len); 105 if (len < 0) { 106 err = copied ? 0 : len; 107 goto unlock; 108 } 109 110 ahash_request_set_crypt(&ctx->req, ctx->sgl.sg, NULL, len); 111 112 err = crypto_wait_req(crypto_ahash_update(&ctx->req), 113 &ctx->wait); 114 af_alg_free_sg(&ctx->sgl); 115 if (err) 116 goto unlock; 117 118 copied += len; 119 iov_iter_advance(&msg->msg_iter, len); 120 } 121 122 err = 0; 123 124 ctx->more = msg->msg_flags & MSG_MORE; 125 if (!ctx->more) { 126 err = hash_alloc_result(sk, ctx); 127 if (err) 128 goto unlock; 129 130 ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0); 131 err = crypto_wait_req(crypto_ahash_final(&ctx->req), 132 &ctx->wait); 133 } 134 135 unlock: 136 release_sock(sk); 137 138 return err ?: copied; 139 } 140 141 static ssize_t hash_sendpage(struct socket *sock, struct page *page, 142 int offset, size_t size, int flags) 143 { 144 struct sock *sk = sock->sk; 145 struct alg_sock *ask = alg_sk(sk); 146 struct hash_ctx *ctx = ask->private; 147 int err; 148 149 if (flags & MSG_SENDPAGE_NOTLAST) 150 flags |= MSG_MORE; 151 152 lock_sock(sk); 153 sg_init_table(ctx->sgl.sg, 1); 154 sg_set_page(ctx->sgl.sg, page, size, offset); 155 156 if (!(flags & MSG_MORE)) { 157 err = hash_alloc_result(sk, ctx); 158 if (err) 159 goto unlock; 160 } else if (!ctx->more) 161 hash_free_result(sk, ctx); 162 163 ahash_request_set_crypt(&ctx->req, ctx->sgl.sg, ctx->result, size); 164 165 if (!(flags & MSG_MORE)) { 166 if (ctx->more) 167 err = crypto_ahash_finup(&ctx->req); 168 else 169 err = crypto_ahash_digest(&ctx->req); 170 } else { 171 if (!ctx->more) { 172 err = crypto_ahash_init(&ctx->req); 173 err = crypto_wait_req(err, &ctx->wait); 174 if (err) 175 goto unlock; 176 } 177 178 err = crypto_ahash_update(&ctx->req); 179 } 180 181 err = crypto_wait_req(err, &ctx->wait); 182 if (err) 183 goto unlock; 184 185 ctx->more = flags & MSG_MORE; 186 187 unlock: 188 release_sock(sk); 189 190 return err ?: size; 191 } 192 193 static int hash_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, 194 int flags) 195 { 196 struct sock *sk = sock->sk; 197 struct alg_sock *ask = alg_sk(sk); 198 struct hash_ctx *ctx = ask->private; 199 unsigned ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req)); 200 bool result; 201 int err; 202 203 if (len > ds) 204 len = ds; 205 else if (len < ds) 206 msg->msg_flags |= MSG_TRUNC; 207 208 lock_sock(sk); 209 result = ctx->result; 210 err = hash_alloc_result(sk, ctx); 211 if (err) 212 goto unlock; 213 214 ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0); 215 216 if (!result && !ctx->more) { 217 err = crypto_wait_req(crypto_ahash_init(&ctx->req), 218 &ctx->wait); 219 if (err) 220 goto unlock; 221 } 222 223 if (!result || ctx->more) { 224 ctx->more = 0; 225 err = crypto_wait_req(crypto_ahash_final(&ctx->req), 226 &ctx->wait); 227 if (err) 228 goto unlock; 229 } 230 231 err = memcpy_to_msg(msg, ctx->result, len); 232 233 unlock: 234 hash_free_result(sk, ctx); 235 release_sock(sk); 236 237 return err ?: len; 238 } 239 240 static int hash_accept(struct socket *sock, struct socket *newsock, int flags, 241 bool kern) 242 { 243 struct sock *sk = sock->sk; 244 struct alg_sock *ask = alg_sk(sk); 245 struct hash_ctx *ctx = ask->private; 246 struct ahash_request *req = &ctx->req; 247 char state[crypto_ahash_statesize(crypto_ahash_reqtfm(req)) ? : 1]; 248 struct sock *sk2; 249 struct alg_sock *ask2; 250 struct hash_ctx *ctx2; 251 bool more; 252 int err; 253 254 lock_sock(sk); 255 more = ctx->more; 256 err = more ? crypto_ahash_export(req, state) : 0; 257 release_sock(sk); 258 259 if (err) 260 return err; 261 262 err = af_alg_accept(ask->parent, newsock, kern); 263 if (err) 264 return err; 265 266 sk2 = newsock->sk; 267 ask2 = alg_sk(sk2); 268 ctx2 = ask2->private; 269 ctx2->more = more; 270 271 if (!more) 272 return err; 273 274 err = crypto_ahash_import(&ctx2->req, state); 275 if (err) { 276 sock_orphan(sk2); 277 sock_put(sk2); 278 } 279 280 return err; 281 } 282 283 static struct proto_ops algif_hash_ops = { 284 .family = PF_ALG, 285 286 .connect = sock_no_connect, 287 .socketpair = sock_no_socketpair, 288 .getname = sock_no_getname, 289 .ioctl = sock_no_ioctl, 290 .listen = sock_no_listen, 291 .shutdown = sock_no_shutdown, 292 .getsockopt = sock_no_getsockopt, 293 .mmap = sock_no_mmap, 294 .bind = sock_no_bind, 295 .setsockopt = sock_no_setsockopt, 296 .poll = sock_no_poll, 297 298 .release = af_alg_release, 299 .sendmsg = hash_sendmsg, 300 .sendpage = hash_sendpage, 301 .recvmsg = hash_recvmsg, 302 .accept = hash_accept, 303 }; 304 305 static int hash_check_key(struct socket *sock) 306 { 307 int err = 0; 308 struct sock *psk; 309 struct alg_sock *pask; 310 struct algif_hash_tfm *tfm; 311 struct sock *sk = sock->sk; 312 struct alg_sock *ask = alg_sk(sk); 313 314 lock_sock(sk); 315 if (ask->refcnt) 316 goto unlock_child; 317 318 psk = ask->parent; 319 pask = alg_sk(ask->parent); 320 tfm = pask->private; 321 322 err = -ENOKEY; 323 lock_sock_nested(psk, SINGLE_DEPTH_NESTING); 324 if (!tfm->has_key) 325 goto unlock; 326 327 if (!pask->refcnt++) 328 sock_hold(psk); 329 330 ask->refcnt = 1; 331 sock_put(psk); 332 333 err = 0; 334 335 unlock: 336 release_sock(psk); 337 unlock_child: 338 release_sock(sk); 339 340 return err; 341 } 342 343 static int hash_sendmsg_nokey(struct socket *sock, struct msghdr *msg, 344 size_t size) 345 { 346 int err; 347 348 err = hash_check_key(sock); 349 if (err) 350 return err; 351 352 return hash_sendmsg(sock, msg, size); 353 } 354 355 static ssize_t hash_sendpage_nokey(struct socket *sock, struct page *page, 356 int offset, size_t size, int flags) 357 { 358 int err; 359 360 err = hash_check_key(sock); 361 if (err) 362 return err; 363 364 return hash_sendpage(sock, page, offset, size, flags); 365 } 366 367 static int hash_recvmsg_nokey(struct socket *sock, struct msghdr *msg, 368 size_t ignored, int flags) 369 { 370 int err; 371 372 err = hash_check_key(sock); 373 if (err) 374 return err; 375 376 return hash_recvmsg(sock, msg, ignored, flags); 377 } 378 379 static int hash_accept_nokey(struct socket *sock, struct socket *newsock, 380 int flags, bool kern) 381 { 382 int err; 383 384 err = hash_check_key(sock); 385 if (err) 386 return err; 387 388 return hash_accept(sock, newsock, flags, kern); 389 } 390 391 static struct proto_ops algif_hash_ops_nokey = { 392 .family = PF_ALG, 393 394 .connect = sock_no_connect, 395 .socketpair = sock_no_socketpair, 396 .getname = sock_no_getname, 397 .ioctl = sock_no_ioctl, 398 .listen = sock_no_listen, 399 .shutdown = sock_no_shutdown, 400 .getsockopt = sock_no_getsockopt, 401 .mmap = sock_no_mmap, 402 .bind = sock_no_bind, 403 .setsockopt = sock_no_setsockopt, 404 .poll = sock_no_poll, 405 406 .release = af_alg_release, 407 .sendmsg = hash_sendmsg_nokey, 408 .sendpage = hash_sendpage_nokey, 409 .recvmsg = hash_recvmsg_nokey, 410 .accept = hash_accept_nokey, 411 }; 412 413 static void *hash_bind(const char *name, u32 type, u32 mask) 414 { 415 struct algif_hash_tfm *tfm; 416 struct crypto_ahash *hash; 417 418 tfm = kzalloc(sizeof(*tfm), GFP_KERNEL); 419 if (!tfm) 420 return ERR_PTR(-ENOMEM); 421 422 hash = crypto_alloc_ahash(name, type, mask); 423 if (IS_ERR(hash)) { 424 kfree(tfm); 425 return ERR_CAST(hash); 426 } 427 428 tfm->hash = hash; 429 430 return tfm; 431 } 432 433 static void hash_release(void *private) 434 { 435 struct algif_hash_tfm *tfm = private; 436 437 crypto_free_ahash(tfm->hash); 438 kfree(tfm); 439 } 440 441 static int hash_setkey(void *private, const u8 *key, unsigned int keylen) 442 { 443 struct algif_hash_tfm *tfm = private; 444 int err; 445 446 err = crypto_ahash_setkey(tfm->hash, key, keylen); 447 tfm->has_key = !err; 448 449 return err; 450 } 451 452 static void hash_sock_destruct(struct sock *sk) 453 { 454 struct alg_sock *ask = alg_sk(sk); 455 struct hash_ctx *ctx = ask->private; 456 457 hash_free_result(sk, ctx); 458 sock_kfree_s(sk, ctx, ctx->len); 459 af_alg_release_parent(sk); 460 } 461 462 static int hash_accept_parent_nokey(void *private, struct sock *sk) 463 { 464 struct hash_ctx *ctx; 465 struct alg_sock *ask = alg_sk(sk); 466 struct algif_hash_tfm *tfm = private; 467 struct crypto_ahash *hash = tfm->hash; 468 unsigned len = sizeof(*ctx) + crypto_ahash_reqsize(hash); 469 470 ctx = sock_kmalloc(sk, len, GFP_KERNEL); 471 if (!ctx) 472 return -ENOMEM; 473 474 ctx->result = NULL; 475 ctx->len = len; 476 ctx->more = 0; 477 crypto_init_wait(&ctx->wait); 478 479 ask->private = ctx; 480 481 ahash_request_set_tfm(&ctx->req, hash); 482 ahash_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG, 483 crypto_req_done, &ctx->wait); 484 485 sk->sk_destruct = hash_sock_destruct; 486 487 return 0; 488 } 489 490 static int hash_accept_parent(void *private, struct sock *sk) 491 { 492 struct algif_hash_tfm *tfm = private; 493 494 if (!tfm->has_key && crypto_ahash_has_setkey(tfm->hash)) 495 return -ENOKEY; 496 497 return hash_accept_parent_nokey(private, sk); 498 } 499 500 static const struct af_alg_type algif_type_hash = { 501 .bind = hash_bind, 502 .release = hash_release, 503 .setkey = hash_setkey, 504 .accept = hash_accept_parent, 505 .accept_nokey = hash_accept_parent_nokey, 506 .ops = &algif_hash_ops, 507 .ops_nokey = &algif_hash_ops_nokey, 508 .name = "hash", 509 .owner = THIS_MODULE 510 }; 511 512 static int __init algif_hash_init(void) 513 { 514 return af_alg_register_type(&algif_type_hash); 515 } 516 517 static void __exit algif_hash_exit(void) 518 { 519 int err = af_alg_unregister_type(&algif_type_hash); 520 BUG_ON(err); 521 } 522 523 module_init(algif_hash_init); 524 module_exit(algif_hash_exit); 525 MODULE_LICENSE("GPL"); 526