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