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 (ctx->more) { 218 ctx->more = 0; 219 err = af_alg_wait_for_completion(crypto_ahash_final(&ctx->req), 220 &ctx->completion); 221 if (err) 222 goto unlock; 223 } else if (!result) { 224 err = af_alg_wait_for_completion( 225 crypto_ahash_digest(&ctx->req), 226 &ctx->completion); 227 } 228 229 err = memcpy_to_msg(msg, ctx->result, len); 230 231 hash_free_result(sk, ctx); 232 233 unlock: 234 release_sock(sk); 235 236 return err ?: len; 237 } 238 239 static int hash_accept(struct socket *sock, struct socket *newsock, int flags) 240 { 241 struct sock *sk = sock->sk; 242 struct alg_sock *ask = alg_sk(sk); 243 struct hash_ctx *ctx = ask->private; 244 struct ahash_request *req = &ctx->req; 245 char state[crypto_ahash_statesize(crypto_ahash_reqtfm(req))]; 246 struct sock *sk2; 247 struct alg_sock *ask2; 248 struct hash_ctx *ctx2; 249 bool more; 250 int err; 251 252 lock_sock(sk); 253 more = ctx->more; 254 err = more ? crypto_ahash_export(req, state) : 0; 255 release_sock(sk); 256 257 if (err) 258 return err; 259 260 err = af_alg_accept(ask->parent, newsock); 261 if (err) 262 return err; 263 264 sk2 = newsock->sk; 265 ask2 = alg_sk(sk2); 266 ctx2 = ask2->private; 267 ctx2->more = more; 268 269 if (!more) 270 return err; 271 272 err = crypto_ahash_import(&ctx2->req, state); 273 if (err) { 274 sock_orphan(sk2); 275 sock_put(sk2); 276 } 277 278 return err; 279 } 280 281 static struct proto_ops algif_hash_ops = { 282 .family = PF_ALG, 283 284 .connect = sock_no_connect, 285 .socketpair = sock_no_socketpair, 286 .getname = sock_no_getname, 287 .ioctl = sock_no_ioctl, 288 .listen = sock_no_listen, 289 .shutdown = sock_no_shutdown, 290 .getsockopt = sock_no_getsockopt, 291 .mmap = sock_no_mmap, 292 .bind = sock_no_bind, 293 .setsockopt = sock_no_setsockopt, 294 .poll = sock_no_poll, 295 296 .release = af_alg_release, 297 .sendmsg = hash_sendmsg, 298 .sendpage = hash_sendpage, 299 .recvmsg = hash_recvmsg, 300 .accept = hash_accept, 301 }; 302 303 static int hash_check_key(struct socket *sock) 304 { 305 int err = 0; 306 struct sock *psk; 307 struct alg_sock *pask; 308 struct algif_hash_tfm *tfm; 309 struct sock *sk = sock->sk; 310 struct alg_sock *ask = alg_sk(sk); 311 312 lock_sock(sk); 313 if (ask->refcnt) 314 goto unlock_child; 315 316 psk = ask->parent; 317 pask = alg_sk(ask->parent); 318 tfm = pask->private; 319 320 err = -ENOKEY; 321 lock_sock_nested(psk, SINGLE_DEPTH_NESTING); 322 if (!tfm->has_key) 323 goto unlock; 324 325 if (!pask->refcnt++) 326 sock_hold(psk); 327 328 ask->refcnt = 1; 329 sock_put(psk); 330 331 err = 0; 332 333 unlock: 334 release_sock(psk); 335 unlock_child: 336 release_sock(sk); 337 338 return err; 339 } 340 341 static int hash_sendmsg_nokey(struct socket *sock, struct msghdr *msg, 342 size_t size) 343 { 344 int err; 345 346 err = hash_check_key(sock); 347 if (err) 348 return err; 349 350 return hash_sendmsg(sock, msg, size); 351 } 352 353 static ssize_t hash_sendpage_nokey(struct socket *sock, struct page *page, 354 int offset, size_t size, int flags) 355 { 356 int err; 357 358 err = hash_check_key(sock); 359 if (err) 360 return err; 361 362 return hash_sendpage(sock, page, offset, size, flags); 363 } 364 365 static int hash_recvmsg_nokey(struct socket *sock, struct msghdr *msg, 366 size_t ignored, int flags) 367 { 368 int err; 369 370 err = hash_check_key(sock); 371 if (err) 372 return err; 373 374 return hash_recvmsg(sock, msg, ignored, flags); 375 } 376 377 static int hash_accept_nokey(struct socket *sock, struct socket *newsock, 378 int flags) 379 { 380 int err; 381 382 err = hash_check_key(sock); 383 if (err) 384 return err; 385 386 return hash_accept(sock, newsock, flags); 387 } 388 389 static struct proto_ops algif_hash_ops_nokey = { 390 .family = PF_ALG, 391 392 .connect = sock_no_connect, 393 .socketpair = sock_no_socketpair, 394 .getname = sock_no_getname, 395 .ioctl = sock_no_ioctl, 396 .listen = sock_no_listen, 397 .shutdown = sock_no_shutdown, 398 .getsockopt = sock_no_getsockopt, 399 .mmap = sock_no_mmap, 400 .bind = sock_no_bind, 401 .setsockopt = sock_no_setsockopt, 402 .poll = sock_no_poll, 403 404 .release = af_alg_release, 405 .sendmsg = hash_sendmsg_nokey, 406 .sendpage = hash_sendpage_nokey, 407 .recvmsg = hash_recvmsg_nokey, 408 .accept = hash_accept_nokey, 409 }; 410 411 static void *hash_bind(const char *name, u32 type, u32 mask) 412 { 413 struct algif_hash_tfm *tfm; 414 struct crypto_ahash *hash; 415 416 tfm = kzalloc(sizeof(*tfm), GFP_KERNEL); 417 if (!tfm) 418 return ERR_PTR(-ENOMEM); 419 420 hash = crypto_alloc_ahash(name, type, mask); 421 if (IS_ERR(hash)) { 422 kfree(tfm); 423 return ERR_CAST(hash); 424 } 425 426 tfm->hash = hash; 427 428 return tfm; 429 } 430 431 static void hash_release(void *private) 432 { 433 struct algif_hash_tfm *tfm = private; 434 435 crypto_free_ahash(tfm->hash); 436 kfree(tfm); 437 } 438 439 static int hash_setkey(void *private, const u8 *key, unsigned int keylen) 440 { 441 struct algif_hash_tfm *tfm = private; 442 int err; 443 444 err = crypto_ahash_setkey(tfm->hash, key, keylen); 445 tfm->has_key = !err; 446 447 return err; 448 } 449 450 static void hash_sock_destruct(struct sock *sk) 451 { 452 struct alg_sock *ask = alg_sk(sk); 453 struct hash_ctx *ctx = ask->private; 454 455 hash_free_result(sk, ctx); 456 sock_kfree_s(sk, ctx, ctx->len); 457 af_alg_release_parent(sk); 458 } 459 460 static int hash_accept_parent_nokey(void *private, struct sock *sk) 461 { 462 struct hash_ctx *ctx; 463 struct alg_sock *ask = alg_sk(sk); 464 struct algif_hash_tfm *tfm = private; 465 struct crypto_ahash *hash = tfm->hash; 466 unsigned len = sizeof(*ctx) + crypto_ahash_reqsize(hash); 467 468 ctx = sock_kmalloc(sk, len, GFP_KERNEL); 469 if (!ctx) 470 return -ENOMEM; 471 472 ctx->result = NULL; 473 ctx->len = len; 474 ctx->more = 0; 475 af_alg_init_completion(&ctx->completion); 476 477 ask->private = ctx; 478 479 ahash_request_set_tfm(&ctx->req, hash); 480 ahash_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG, 481 af_alg_complete, &ctx->completion); 482 483 sk->sk_destruct = hash_sock_destruct; 484 485 return 0; 486 } 487 488 static int hash_accept_parent(void *private, struct sock *sk) 489 { 490 struct algif_hash_tfm *tfm = private; 491 492 if (!tfm->has_key && crypto_ahash_has_setkey(tfm->hash)) 493 return -ENOKEY; 494 495 return hash_accept_parent_nokey(private, sk); 496 } 497 498 static const struct af_alg_type algif_type_hash = { 499 .bind = hash_bind, 500 .release = hash_release, 501 .setkey = hash_setkey, 502 .accept = hash_accept_parent, 503 .accept_nokey = hash_accept_parent_nokey, 504 .ops = &algif_hash_ops, 505 .ops_nokey = &algif_hash_ops_nokey, 506 .name = "hash", 507 .owner = THIS_MODULE 508 }; 509 510 static int __init algif_hash_init(void) 511 { 512 return af_alg_register_type(&algif_type_hash); 513 } 514 515 static void __exit algif_hash_exit(void) 516 { 517 int err = af_alg_unregister_type(&algif_type_hash); 518 BUG_ON(err); 519 } 520 521 module_init(algif_hash_init); 522 module_exit(algif_hash_exit); 523 MODULE_LICENSE("GPL"); 524