crypto/algif_hash.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * algif_hash: User-space interface for hash algorithms
   4  *
   5  * This file provides the user-space API for hash algorithms.
   6  *
   7  * Copyright (c) 2010 Herbert Xu <herbert@gondor.apana.org.au>
   8  */
   9
  10 #include <crypto/hash.h>
  11 #include <crypto/if_alg.h>
  12 #include <linux/init.h>
  13 #include <linux/kernel.h>
  14 #include <linux/mm.h>
  15 #include <linux/module.h>
  16 #include <linux/net.h>
  17 #include <net/sock.h>
  18
  19 struct hash_ctx {
  20         struct af_alg_sgl sgl;
  21
  22         u8 *result;
  23
  24         struct crypto_wait wait;
  25
  26         unsigned int len;
  27         bool more;
  28
  29         struct ahash_request req;
  30 };
  31
  32 static int hash_alloc_result(struct sock *sk, struct hash_ctx *ctx)
  33 {
  34         unsigned ds;
  35
  36         if (ctx->result)
  37                 return 0;
  38
  39         ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req));
  40
  41         ctx->result = sock_kmalloc(sk, ds, GFP_KERNEL);
  42         if (!ctx->result)
  43                 return -ENOMEM;
  44
  45         memset(ctx->result, 0, ds);
  46
  47         return 0;
  48 }
  49
  50 static void hash_free_result(struct sock *sk, struct hash_ctx *ctx)
  51 {
  52         unsigned ds;
  53
  54         if (!ctx->result)
  55                 return;
  56
  57         ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req));
  58
  59         sock_kzfree_s(sk, ctx->result, ds);
  60         ctx->result = NULL;
  61 }
  62
  63 static int hash_sendmsg(struct socket *sock, struct msghdr *msg,
  64                         size_t ignored)
  65 {
  66         int limit = ALG_MAX_PAGES * PAGE_SIZE;
  67         struct sock *sk = sock->sk;
  68         struct alg_sock *ask = alg_sk(sk);
  69         struct hash_ctx *ctx = ask->private;
  70         long copied = 0;
  71         int err;
  72
  73         if (limit > sk->sk_sndbuf)
  74                 limit = sk->sk_sndbuf;
  75
  76         lock_sock(sk);
  77         if (!ctx->more) {
  78                 if ((msg->msg_flags & MSG_MORE))
  79                         hash_free_result(sk, ctx);
  80
  81                 err = crypto_wait_req(crypto_ahash_init(&ctx->req), &ctx->wait);
  82                 if (err)
  83                         goto unlock;
  84         }
  85
  86         ctx->more = false;
  87
  88         while (msg_data_left(msg)) {
  89                 int len = msg_data_left(msg);
  90
  91                 if (len > limit)
  92                         len = limit;
  93
  94                 len = af_alg_make_sg(&ctx->sgl, &msg->msg_iter, len);
  95                 if (len < 0) {
  96                         err = copied ? 0 : len;
  97                         goto unlock;
  98                 }
  99
 100                 ahash_request_set_crypt(&ctx->req, ctx->sgl.sg, NULL, len);
 101
 102                 err = crypto_wait_req(crypto_ahash_update(&ctx->req),
 103                                       &ctx->wait);
 104                 af_alg_free_sg(&ctx->sgl);
 105                 if (err)
 106                         goto unlock;
 107
 108                 copied += len;
 109                 iov_iter_advance(&msg->msg_iter, len);
 110         }
 111
 112         err = 0;
 113
 114         ctx->more = msg->msg_flags & MSG_MORE;
 115         if (!ctx->more) {
 116                 err = hash_alloc_result(sk, ctx);
 117                 if (err)
 118                         goto unlock;
 119
 120                 ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0);
 121                 err = crypto_wait_req(crypto_ahash_final(&ctx->req),
 122                                       &ctx->wait);
 123         }
 124
 125 unlock:
 126         release_sock(sk);
 127
 128         return err ?: copied;
 129 }
 130
 131 static ssize_t hash_sendpage(struct socket *sock, struct page *page,
 132                              int offset, size_t size, int flags)
 133 {
 134         struct sock *sk = sock->sk;
 135         struct alg_sock *ask = alg_sk(sk);
 136         struct hash_ctx *ctx = ask->private;
 137         int err;
 138
 139         if (flags & MSG_SENDPAGE_NOTLAST)
 140                 flags |= MSG_MORE;
 141
 142         lock_sock(sk);
 143         sg_init_table(ctx->sgl.sg, 1);
 144         sg_set_page(ctx->sgl.sg, page, size, offset);
 145
 146         if (!(flags & MSG_MORE)) {
 147                 err = hash_alloc_result(sk, ctx);
 148                 if (err)
 149                         goto unlock;
 150         } else if (!ctx->more)
 151                 hash_free_result(sk, ctx);
 152
 153         ahash_request_set_crypt(&ctx->req, ctx->sgl.sg, ctx->result, size);
 154
 155         if (!(flags & MSG_MORE)) {
 156                 if (ctx->more)
 157                         err = crypto_ahash_finup(&ctx->req);
 158                 else
 159                         err = crypto_ahash_digest(&ctx->req);
 160         } else {
 161                 if (!ctx->more) {
 162                         err = crypto_ahash_init(&ctx->req);
 163                         err = crypto_wait_req(err, &ctx->wait);
 164                         if (err)
 165                                 goto unlock;
 166                 }
 167
 168                 err = crypto_ahash_update(&ctx->req);
 169         }
 170
 171         err = crypto_wait_req(err, &ctx->wait);
 172         if (err)
 173                 goto unlock;
 174
 175         ctx->more = flags & MSG_MORE;
 176
 177 unlock:
 178         release_sock(sk);
 179
 180         return err ?: size;
 181 }
 182
 183 static int hash_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
 184                         int flags)
 185 {
 186         struct sock *sk = sock->sk;
 187         struct alg_sock *ask = alg_sk(sk);
 188         struct hash_ctx *ctx = ask->private;
 189         unsigned ds = crypto_ahash_digestsize(crypto_ahash_reqtfm(&ctx->req));
 190         bool result;
 191         int err;
 192
 193         if (len > ds)
 194                 len = ds;
 195         else if (len < ds)
 196                 msg->msg_flags |= MSG_TRUNC;
 197
 198         lock_sock(sk);
 199         result = ctx->result;
 200         err = hash_alloc_result(sk, ctx);
 201         if (err)
 202                 goto unlock;
 203
 204         ahash_request_set_crypt(&ctx->req, NULL, ctx->result, 0);
 205
 206         if (!result && !ctx->more) {
 207                 err = crypto_wait_req(crypto_ahash_init(&ctx->req),
 208                                       &ctx->wait);
 209                 if (err)
 210                         goto unlock;
 211         }
 212
 213         if (!result || ctx->more) {
 214                 ctx->more = false;
 215                 err = crypto_wait_req(crypto_ahash_final(&ctx->req),
 216                                       &ctx->wait);
 217                 if (err)
 218                         goto unlock;
 219         }
 220
 221         err = memcpy_to_msg(msg, ctx->result, len);
 222
 223 unlock:
 224         hash_free_result(sk, ctx);
 225         release_sock(sk);
 226
 227         return err ?: len;
 228 }
 229
 230 static int hash_accept(struct socket *sock, struct socket *newsock, int flags,
 231                        bool kern)
 232 {
 233         struct sock *sk = sock->sk;
 234         struct alg_sock *ask = alg_sk(sk);
 235         struct hash_ctx *ctx = ask->private;
 236         struct ahash_request *req = &ctx->req;
 237         char state[HASH_MAX_STATESIZE];
 238         struct sock *sk2;
 239         struct alg_sock *ask2;
 240         struct hash_ctx *ctx2;
 241         bool more;
 242         int err;
 243
 244         lock_sock(sk);
 245         more = ctx->more;
 246         err = more ? crypto_ahash_export(req, state) : 0;
 247         release_sock(sk);
 248
 249         if (err)
 250                 return err;
 251
 252         err = af_alg_accept(ask->parent, newsock, kern);
 253         if (err)
 254                 return err;
 255
 256         sk2 = newsock->sk;
 257         ask2 = alg_sk(sk2);
 258         ctx2 = ask2->private;
 259         ctx2->more = more;
 260
 261         if (!more)
 262                 return err;
 263
 264         err = crypto_ahash_import(&ctx2->req, state);
 265         if (err) {
 266                 sock_orphan(sk2);
 267                 sock_put(sk2);
 268         }
 269
 270         return err;
 271 }
 272
 273 static struct proto_ops algif_hash_ops = {
 274         .family         =       PF_ALG,
 275
 276         .connect        =       sock_no_connect,
 277         .socketpair     =       sock_no_socketpair,
 278         .getname        =       sock_no_getname,
 279         .ioctl          =       sock_no_ioctl,
 280         .listen         =       sock_no_listen,
 281         .shutdown       =       sock_no_shutdown,
 282         .mmap           =       sock_no_mmap,
 283         .bind           =       sock_no_bind,
 284
 285         .release        =       af_alg_release,
 286         .sendmsg        =       hash_sendmsg,
 287         .sendpage       =       hash_sendpage,
 288         .recvmsg        =       hash_recvmsg,
 289         .accept         =       hash_accept,
 290 };
 291
 292 static int hash_check_key(struct socket *sock)
 293 {
 294         int err = 0;
 295         struct sock *psk;
 296         struct alg_sock *pask;
 297         struct crypto_ahash *tfm;
 298         struct sock *sk = sock->sk;
 299         struct alg_sock *ask = alg_sk(sk);
 300
 301         lock_sock(sk);
 302         if (!atomic_read(&ask->nokey_refcnt))
 303                 goto unlock_child;
 304
 305         psk = ask->parent;
 306         pask = alg_sk(ask->parent);
 307         tfm = pask->private;
 308
 309         err = -ENOKEY;
 310         lock_sock_nested(psk, SINGLE_DEPTH_NESTING);
 311         if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
 312                 goto unlock;
 313
 314         atomic_dec(&pask->nokey_refcnt);
 315         atomic_set(&ask->nokey_refcnt, 0);
 316
 317         err = 0;
 318
 319 unlock:
 320         release_sock(psk);
 321 unlock_child:
 322         release_sock(sk);
 323
 324         return err;
 325 }
 326
 327 static int hash_sendmsg_nokey(struct socket *sock, struct msghdr *msg,
 328                               size_t size)
 329 {
 330         int err;
 331
 332         err = hash_check_key(sock);
 333         if (err)
 334                 return err;
 335
 336         return hash_sendmsg(sock, msg, size);
 337 }
 338
 339 static ssize_t hash_sendpage_nokey(struct socket *sock, struct page *page,
 340                                    int offset, size_t size, int flags)
 341 {
 342         int err;
 343
 344         err = hash_check_key(sock);
 345         if (err)
 346                 return err;
 347
 348         return hash_sendpage(sock, page, offset, size, flags);
 349 }
 350
 351 static int hash_recvmsg_nokey(struct socket *sock, struct msghdr *msg,
 352                               size_t ignored, int flags)
 353 {
 354         int err;
 355
 356         err = hash_check_key(sock);
 357         if (err)
 358                 return err;
 359
 360         return hash_recvmsg(sock, msg, ignored, flags);
 361 }
 362
 363 static int hash_accept_nokey(struct socket *sock, struct socket *newsock,
 364                              int flags, bool kern)
 365 {
 366         int err;
 367
 368         err = hash_check_key(sock);
 369         if (err)
 370                 return err;
 371
 372         return hash_accept(sock, newsock, flags, kern);
 373 }
 374
 375 static struct proto_ops algif_hash_ops_nokey = {
 376         .family         =       PF_ALG,
 377
 378         .connect        =       sock_no_connect,
 379         .socketpair     =       sock_no_socketpair,
 380         .getname        =       sock_no_getname,
 381         .ioctl          =       sock_no_ioctl,
 382         .listen         =       sock_no_listen,
 383         .shutdown       =       sock_no_shutdown,
 384         .mmap           =       sock_no_mmap,
 385         .bind           =       sock_no_bind,
 386
 387         .release        =       af_alg_release,
 388         .sendmsg        =       hash_sendmsg_nokey,
 389         .sendpage       =       hash_sendpage_nokey,
 390         .recvmsg        =       hash_recvmsg_nokey,
 391         .accept         =       hash_accept_nokey,
 392 };
 393
 394 static void *hash_bind(const char *name, u32 type, u32 mask)
 395 {
 396         return crypto_alloc_ahash(name, type, mask);
 397 }
 398
 399 static void hash_release(void *private)
 400 {
 401         crypto_free_ahash(private);
 402 }
 403
 404 static int hash_setkey(void *private, const u8 *key, unsigned int keylen)
 405 {
 406         return crypto_ahash_setkey(private, key, keylen);
 407 }
 408
 409 static void hash_sock_destruct(struct sock *sk)
 410 {
 411         struct alg_sock *ask = alg_sk(sk);
 412         struct hash_ctx *ctx = ask->private;
 413
 414         hash_free_result(sk, ctx);
 415         sock_kfree_s(sk, ctx, ctx->len);
 416         af_alg_release_parent(sk);
 417 }
 418
 419 static int hash_accept_parent_nokey(void *private, struct sock *sk)
 420 {
 421         struct crypto_ahash *tfm = private;
 422         struct alg_sock *ask = alg_sk(sk);
 423         struct hash_ctx *ctx;
 424         unsigned int len = sizeof(*ctx) + crypto_ahash_reqsize(tfm);
 425
 426         ctx = sock_kmalloc(sk, len, GFP_KERNEL);
 427         if (!ctx)
 428                 return -ENOMEM;
 429
 430         ctx->result = NULL;
 431         ctx->len = len;
 432         ctx->more = false;
 433         crypto_init_wait(&ctx->wait);
 434
 435         ask->private = ctx;
 436
 437         ahash_request_set_tfm(&ctx->req, tfm);
 438         ahash_request_set_callback(&ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG,
 439                                    crypto_req_done, &ctx->wait);
 440
 441         sk->sk_destruct = hash_sock_destruct;
 442
 443         return 0;
 444 }
 445
 446 static int hash_accept_parent(void *private, struct sock *sk)
 447 {
 448         struct crypto_ahash *tfm = private;
 449
 450         if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
 451                 return -ENOKEY;
 452
 453         return hash_accept_parent_nokey(private, sk);
 454 }
 455
 456 static const struct af_alg_type algif_type_hash = {
 457         .bind           =       hash_bind,
 458         .release        =       hash_release,
 459         .setkey         =       hash_setkey,
 460         .accept         =       hash_accept_parent,
 461         .accept_nokey   =       hash_accept_parent_nokey,
 462         .ops            =       &algif_hash_ops,
 463         .ops_nokey      =       &algif_hash_ops_nokey,
 464         .name           =       "hash",
 465         .owner          =       THIS_MODULE
 466 };
 467
 468 static int __init algif_hash_init(void)
 469 {
 470         return af_alg_register_type(&algif_type_hash);
 471 }
 472
 473 static void __exit algif_hash_exit(void)
 474 {
 475         int err = af_alg_unregister_type(&algif_type_hash);
 476         BUG_ON(err);
 477 }
 478
 479 module_init(algif_hash_init);
 480 module_exit(algif_hash_exit);
 481 MODULE_LICENSE("GPL");