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