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 { 244 struct sock *sk = sock->sk; 245 struct alg_sock *ask = alg_sk(sk); 246 struct hash_ctx *ctx = ask->private; 247 struct ahash_request *req = &ctx->req; 248 char state[crypto_ahash_statesize(crypto_ahash_reqtfm(req))]; 249 struct sock *sk2; 250 struct alg_sock *ask2; 251 struct hash_ctx *ctx2; 252 bool more; 253 int err; 254 255 lock_sock(sk); 256 more = ctx->more; 257 err = more ? crypto_ahash_export(req, state) : 0; 258 release_sock(sk); 259 260 if (err) 261 return err; 262 263 err = af_alg_accept(ask->parent, newsock); 264 if (err) 265 return err; 266 267 sk2 = newsock->sk; 268 ask2 = alg_sk(sk2); 269 ctx2 = ask2->private; 270 ctx2->more = more; 271 272 if (!more) 273 return err; 274 275 err = crypto_ahash_import(&ctx2->req, state); 276 if (err) { 277 sock_orphan(sk2); 278 sock_put(sk2); 279 } 280 281 return err; 282 } 283 284 static struct proto_ops algif_hash_ops = { 285 .family = PF_ALG, 286 287 .connect = sock_no_connect, 288 .socketpair = sock_no_socketpair, 289 .getname = sock_no_getname, 290 .ioctl = sock_no_ioctl, 291 .listen = sock_no_listen, 292 .shutdown = sock_no_shutdown, 293 .getsockopt = sock_no_getsockopt, 294 .mmap = sock_no_mmap, 295 .bind = sock_no_bind, 296 .setsockopt = sock_no_setsockopt, 297 .poll = sock_no_poll, 298 299 .release = af_alg_release, 300 .sendmsg = hash_sendmsg, 301 .sendpage = hash_sendpage, 302 .recvmsg = hash_recvmsg, 303 .accept = hash_accept, 304 }; 305 306 static int hash_check_key(struct socket *sock) 307 { 308 int err = 0; 309 struct sock *psk; 310 struct alg_sock *pask; 311 struct algif_hash_tfm *tfm; 312 struct sock *sk = sock->sk; 313 struct alg_sock *ask = alg_sk(sk); 314 315 lock_sock(sk); 316 if (ask->refcnt) 317 goto unlock_child; 318 319 psk = ask->parent; 320 pask = alg_sk(ask->parent); 321 tfm = pask->private; 322 323 err = -ENOKEY; 324 lock_sock_nested(psk, SINGLE_DEPTH_NESTING); 325 if (!tfm->has_key) 326 goto unlock; 327 328 if (!pask->refcnt++) 329 sock_hold(psk); 330 331 ask->refcnt = 1; 332 sock_put(psk); 333 334 err = 0; 335 336 unlock: 337 release_sock(psk); 338 unlock_child: 339 release_sock(sk); 340 341 return err; 342 } 343 344 static int hash_sendmsg_nokey(struct socket *sock, struct msghdr *msg, 345 size_t size) 346 { 347 int err; 348 349 err = hash_check_key(sock); 350 if (err) 351 return err; 352 353 return hash_sendmsg(sock, msg, size); 354 } 355 356 static ssize_t hash_sendpage_nokey(struct socket *sock, struct page *page, 357 int offset, size_t size, int flags) 358 { 359 int err; 360 361 err = hash_check_key(sock); 362 if (err) 363 return err; 364 365 return hash_sendpage(sock, page, offset, size, flags); 366 } 367 368 static int hash_recvmsg_nokey(struct socket *sock, struct msghdr *msg, 369 size_t ignored, int flags) 370 { 371 int err; 372 373 err = hash_check_key(sock); 374 if (err) 375 return err; 376 377 return hash_recvmsg(sock, msg, ignored, flags); 378 } 379 380 static int hash_accept_nokey(struct socket *sock, struct socket *newsock, 381 int flags) 382 { 383 int err; 384 385 err = hash_check_key(sock); 386 if (err) 387 return err; 388 389 return hash_accept(sock, newsock, flags); 390 } 391 392 static struct proto_ops algif_hash_ops_nokey = { 393 .family = PF_ALG, 394 395 .connect = sock_no_connect, 396 .socketpair = sock_no_socketpair, 397 .getname = sock_no_getname, 398 .ioctl = sock_no_ioctl, 399 .listen = sock_no_listen, 400 .shutdown = sock_no_shutdown, 401 .getsockopt = sock_no_getsockopt, 402 .mmap = sock_no_mmap, 403 .bind = sock_no_bind, 404 .setsockopt = sock_no_setsockopt, 405 .poll = sock_no_poll, 406 407 .release = af_alg_release, 408 .sendmsg = hash_sendmsg_nokey, 409 .sendpage = hash_sendpage_nokey, 410 .recvmsg = hash_recvmsg_nokey, 411 .accept = hash_accept_nokey, 412 }; 413 414 static void *hash_bind(const char *name, u32 type, u32 mask) 415 { 416 struct algif_hash_tfm *tfm; 417 struct crypto_ahash *hash; 418 419 tfm = kzalloc(sizeof(*tfm), GFP_KERNEL); 420 if (!tfm) 421 return ERR_PTR(-ENOMEM); 422 423 hash = crypto_alloc_ahash(name, type, mask); 424 if (IS_ERR(hash)) { 425 kfree(tfm); 426 return ERR_CAST(hash); 427 } 428 429 tfm->hash = hash; 430 431 return tfm; 432 } 433 434 static void hash_release(void *private) 435 { 436 struct algif_hash_tfm *tfm = private; 437 438 crypto_free_ahash(tfm->hash); 439 kfree(tfm); 440 } 441 442 static int hash_setkey(void *private, const u8 *key, unsigned int keylen) 443 { 444 struct algif_hash_tfm *tfm = private; 445 int err; 446 447 err = crypto_ahash_setkey(tfm->hash, key, keylen); 448 tfm->has_key = !err; 449 450 return err; 451 } 452 453 static void hash_sock_destruct(struct sock *sk) 454 { 455 struct alg_sock *ask = alg_sk(sk); 456 struct hash_ctx *ctx = ask->private; 457 458 hash_free_result(sk, ctx); 459 sock_kfree_s(sk, ctx, ctx->len); 460 af_alg_release_parent(sk); 461 } 462 463 static int hash_accept_parent_nokey(void *private, struct sock *sk) 464 { 465 struct hash_ctx *ctx; 466 struct alg_sock *ask = alg_sk(sk); 467 struct algif_hash_tfm *tfm = private; 468 struct crypto_ahash *hash = tfm->hash; 469 unsigned len = sizeof(*ctx) + crypto_ahash_reqsize(hash); 470 471 ctx = sock_kmalloc(sk, len, GFP_KERNEL); 472 if (!ctx) 473 return -ENOMEM; 474 475 ctx->result = NULL; 476 ctx->len = len; 477 ctx->more = 0; 478 af_alg_init_completion(&ctx->completion); 479 480 ask->private = ctx; 481 482 ahash_request_set_tfm(&ctx->req, hash); 483 ahash_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG, 484 af_alg_complete, &ctx->completion); 485 486 sk->sk_destruct = hash_sock_destruct; 487 488 return 0; 489 } 490 491 static int hash_accept_parent(void *private, struct sock *sk) 492 { 493 struct algif_hash_tfm *tfm = private; 494 495 if (!tfm->has_key && crypto_ahash_has_setkey(tfm->hash)) 496 return -ENOKEY; 497 498 return hash_accept_parent_nokey(private, sk); 499 } 500 501 static const struct af_alg_type algif_type_hash = { 502 .bind = hash_bind, 503 .release = hash_release, 504 .setkey = hash_setkey, 505 .accept = hash_accept_parent, 506 .accept_nokey = hash_accept_parent_nokey, 507 .ops = &algif_hash_ops, 508 .ops_nokey = &algif_hash_ops_nokey, 509 .name = "hash", 510 .owner = THIS_MODULE 511 }; 512 513 static int __init algif_hash_init(void) 514 { 515 return af_alg_register_type(&algif_type_hash); 516 } 517 518 static void __exit algif_hash_exit(void) 519 { 520 int err = af_alg_unregister_type(&algif_type_hash); 521 BUG_ON(err); 522 } 523 524 module_init(algif_hash_init); 525 module_exit(algif_hash_exit); 526 MODULE_LICENSE("GPL"); 527