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