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