crypto/algif_hash.c

   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");