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