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