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