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))];
 188         struct sock *sk2;
 189         struct alg_sock *ask2;
 190         struct hash_ctx *ctx2;
 191         int err;
 192
 193         err = crypto_ahash_export(req, state);
 194         if (err)
 195                 return err;
 196
 197         err = af_alg_accept(ask->parent, newsock);
 198         if (err)
 199                 return err;
 200
 201         sk2 = newsock->sk;
 202         ask2 = alg_sk(sk2);
 203         ctx2 = ask2->private;
 204         ctx2->more = 1;
 205
 206         err = crypto_ahash_import(&ctx2->req, state);
 207         if (err) {
 208                 sock_orphan(sk2);
 209                 sock_put(sk2);
 210         }
 211
 212         return err;
 213 }
 214
 215 static struct proto_ops algif_hash_ops = {
 216         .family         =       PF_ALG,
 217
 218         .connect        =       sock_no_connect,
 219         .socketpair     =       sock_no_socketpair,
 220         .getname        =       sock_no_getname,
 221         .ioctl          =       sock_no_ioctl,
 222         .listen         =       sock_no_listen,
 223         .shutdown       =       sock_no_shutdown,
 224         .getsockopt     =       sock_no_getsockopt,
 225         .mmap           =       sock_no_mmap,
 226         .bind           =       sock_no_bind,
 227         .setsockopt     =       sock_no_setsockopt,
 228         .poll           =       sock_no_poll,
 229
 230         .release        =       af_alg_release,
 231         .sendmsg        =       hash_sendmsg,
 232         .sendpage       =       hash_sendpage,
 233         .recvmsg        =       hash_recvmsg,
 234         .accept         =       hash_accept,
 235 };
 236
 237 static int hash_check_key(struct socket *sock)
 238 {
 239         int err = 0;
 240         struct sock *psk;
 241         struct alg_sock *pask;
 242         struct algif_hash_tfm *tfm;
 243         struct sock *sk = sock->sk;
 244         struct alg_sock *ask = alg_sk(sk);
 245
 246         lock_sock(sk);
 247         if (ask->refcnt)
 248                 goto unlock_child;
 249
 250         psk = ask->parent;
 251         pask = alg_sk(ask->parent);
 252         tfm = pask->private;
 253
 254         err = -ENOKEY;
 255         lock_sock_nested(psk, SINGLE_DEPTH_NESTING);
 256         if (!tfm->has_key)
 257                 goto unlock;
 258
 259         if (!pask->refcnt++)
 260                 sock_hold(psk);
 261
 262         ask->refcnt = 1;
 263         sock_put(psk);
 264
 265         err = 0;
 266
 267 unlock:
 268         release_sock(psk);
 269 unlock_child:
 270         release_sock(sk);
 271
 272         return err;
 273 }
 274
 275 static int hash_sendmsg_nokey(struct socket *sock, struct msghdr *msg,
 276                               size_t size)
 277 {
 278         int err;
 279
 280         err = hash_check_key(sock);
 281         if (err)
 282                 return err;
 283
 284         return hash_sendmsg(sock, msg, size);
 285 }
 286
 287 static ssize_t hash_sendpage_nokey(struct socket *sock, struct page *page,
 288                                    int offset, size_t size, int flags)
 289 {
 290         int err;
 291
 292         err = hash_check_key(sock);
 293         if (err)
 294                 return err;
 295
 296         return hash_sendpage(sock, page, offset, size, flags);
 297 }
 298
 299 static int hash_recvmsg_nokey(struct socket *sock, struct msghdr *msg,
 300                               size_t ignored, int flags)
 301 {
 302         int err;
 303
 304         err = hash_check_key(sock);
 305         if (err)
 306                 return err;
 307
 308         return hash_recvmsg(sock, msg, ignored, flags);
 309 }
 310
 311 static int hash_accept_nokey(struct socket *sock, struct socket *newsock,
 312                              int flags)
 313 {
 314         int err;
 315
 316         err = hash_check_key(sock);
 317         if (err)
 318                 return err;
 319
 320         return hash_accept(sock, newsock, flags);
 321 }
 322
 323 static struct proto_ops algif_hash_ops_nokey = {
 324         .family         =       PF_ALG,
 325
 326         .connect        =       sock_no_connect,
 327         .socketpair     =       sock_no_socketpair,
 328         .getname        =       sock_no_getname,
 329         .ioctl          =       sock_no_ioctl,
 330         .listen         =       sock_no_listen,
 331         .shutdown       =       sock_no_shutdown,
 332         .getsockopt     =       sock_no_getsockopt,
 333         .mmap           =       sock_no_mmap,
 334         .bind           =       sock_no_bind,
 335         .setsockopt     =       sock_no_setsockopt,
 336         .poll           =       sock_no_poll,
 337
 338         .release        =       af_alg_release,
 339         .sendmsg        =       hash_sendmsg_nokey,
 340         .sendpage       =       hash_sendpage_nokey,
 341         .recvmsg        =       hash_recvmsg_nokey,
 342         .accept         =       hash_accept_nokey,
 343 };
 344
 345 static void *hash_bind(const char *name, u32 type, u32 mask)
 346 {
 347         struct algif_hash_tfm *tfm;
 348         struct crypto_ahash *hash;
 349
 350         tfm = kzalloc(sizeof(*tfm), GFP_KERNEL);
 351         if (!tfm)
 352                 return ERR_PTR(-ENOMEM);
 353
 354         hash = crypto_alloc_ahash(name, type, mask);
 355         if (IS_ERR(hash)) {
 356                 kfree(tfm);
 357                 return ERR_CAST(hash);
 358         }
 359
 360         tfm->hash = hash;
 361
 362         return tfm;
 363 }
 364
 365 static void hash_release(void *private)
 366 {
 367         struct algif_hash_tfm *tfm = private;
 368
 369         crypto_free_ahash(tfm->hash);
 370         kfree(tfm);
 371 }
 372
 373 static int hash_setkey(void *private, const u8 *key, unsigned int keylen)
 374 {
 375         struct algif_hash_tfm *tfm = private;
 376         int err;
 377
 378         err = crypto_ahash_setkey(tfm->hash, key, keylen);
 379         tfm->has_key = !err;
 380
 381         return err;
 382 }
 383
 384 static void hash_sock_destruct(struct sock *sk)
 385 {
 386         struct alg_sock *ask = alg_sk(sk);
 387         struct hash_ctx *ctx = ask->private;
 388
 389         sock_kzfree_s(sk, ctx->result,
 390                       crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req)));
 391         sock_kfree_s(sk, ctx, ctx->len);
 392         af_alg_release_parent(sk);
 393 }
 394
 395 static int hash_accept_parent_nokey(void *private, struct sock *sk)
 396 {
 397         struct hash_ctx *ctx;
 398         struct alg_sock *ask = alg_sk(sk);
 399         struct algif_hash_tfm *tfm = private;
 400         struct crypto_ahash *hash = tfm->hash;
 401         unsigned len = sizeof(*ctx) + crypto_ahash_reqsize(hash);
 402         unsigned ds = crypto_ahash_digestsize(hash);
 403
 404         ctx = sock_kmalloc(sk, len, GFP_KERNEL);
 405         if (!ctx)
 406                 return -ENOMEM;
 407
 408         ctx->result = sock_kmalloc(sk, ds, GFP_KERNEL);
 409         if (!ctx->result) {
 410                 sock_kfree_s(sk, ctx, len);
 411                 return -ENOMEM;
 412         }
 413
 414         memset(ctx->result, 0, ds);
 415
 416         ctx->len = len;
 417         ctx->more = 0;
 418         af_alg_init_completion(&ctx->completion);
 419
 420         ask->private = ctx;
 421
 422         ahash_request_set_tfm(&ctx->req, hash);
 423         ahash_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG,
 424                                    af_alg_complete, &ctx->completion);
 425
 426         sk->sk_destruct = hash_sock_destruct;
 427
 428         return 0;
 429 }
 430
 431 static int hash_accept_parent(void *private, struct sock *sk)
 432 {
 433         struct algif_hash_tfm *tfm = private;
 434
 435         if (!tfm->has_key && crypto_ahash_has_setkey(tfm->hash))
 436                 return -ENOKEY;
 437
 438         return hash_accept_parent_nokey(private, sk);
 439 }
 440
 441 static const struct af_alg_type algif_type_hash = {
 442         .bind           =       hash_bind,
 443         .release        =       hash_release,
 444         .setkey         =       hash_setkey,
 445         .accept         =       hash_accept_parent,
 446         .accept_nokey   =       hash_accept_parent_nokey,
 447         .ops            =       &algif_hash_ops,
 448         .ops_nokey      =       &algif_hash_ops_nokey,
 449         .name           =       "hash",
 450         .owner          =       THIS_MODULE
 451 };
 452
 453 static int __init algif_hash_init(void)
 454 {
 455         return af_alg_register_type(&algif_type_hash);
 456 }
 457
 458 static void __exit algif_hash_exit(void)
 459 {
 460         int err = af_alg_unregister_type(&algif_type_hash);
 461         BUG_ON(err);
 462 }
 463
 464 module_init(algif_hash_init);
 465 module_exit(algif_hash_exit);
 466 MODULE_LICENSE("GPL");