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 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");