linux/crypto/algif_hash.c
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   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
  19struct 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
  32static 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
  50static 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
  63static 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
 125unlock:
 126        release_sock(sk);
 127
 128        return err ?: copied;
 129}
 130
 131static 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
 177unlock:
 178        release_sock(sk);
 179
 180        return err ?: size;
 181}
 182
 183static 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
 223unlock:
 224        hash_free_result(sk, ctx);
 225        release_sock(sk);
 226
 227        return err ?: len;
 228}
 229
 230static 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
 273static 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
 292static 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
 319unlock:
 320        release_sock(psk);
 321unlock_child:
 322        release_sock(sk);
 323
 324        return err;
 325}
 326
 327static 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
 339static 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
 351static 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
 363static 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
 375static 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
 394static void *hash_bind(const char *name, u32 type, u32 mask)
 395{
 396        return crypto_alloc_ahash(name, type, mask);
 397}
 398
 399static void hash_release(void *private)
 400{
 401        crypto_free_ahash(private);
 402}
 403
 404static int hash_setkey(void *private, const u8 *key, unsigned int keylen)
 405{
 406        return crypto_ahash_setkey(private, key, keylen);
 407}
 408
 409static 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
 419static 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
 446static 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
 456static 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
 468static int __init algif_hash_init(void)
 469{
 470        return af_alg_register_type(&algif_type_hash);
 471}
 472
 473static void __exit algif_hash_exit(void)
 474{
 475        int err = af_alg_unregister_type(&algif_type_hash);
 476        BUG_ON(err);
 477}
 478
 479module_init(algif_hash_init);
 480module_exit(algif_hash_exit);
 481MODULE_LICENSE("GPL");
 482
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