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