crypto/af_alg.c

   1 /*
   2  * af_alg: User-space algorithm interface
   3  *
   4  * This file provides the user-space API for 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 <linux/atomic.h>
  16 #include <crypto/if_alg.h>
  17 #include <linux/crypto.h>
  18 #include <linux/init.h>
  19 #include <linux/kernel.h>
  20 #include <linux/list.h>
  21 #include <linux/module.h>
  22 #include <linux/net.h>
  23 #include <linux/rwsem.h>
  24 #include <linux/sched/signal.h>
  25 #include <linux/security.h>
  26
  27 struct alg_type_list {
  28         const struct af_alg_type *type;
  29         struct list_head list;
  30 };
  31
  32 static atomic_long_t alg_memory_allocated;
  33
  34 static struct proto alg_proto = {
  35         .name                   = "ALG",
  36         .owner                  = THIS_MODULE,
  37         .memory_allocated       = &alg_memory_allocated,
  38         .obj_size               = sizeof(struct alg_sock),
  39 };
  40
  41 static LIST_HEAD(alg_types);
  42 static DECLARE_RWSEM(alg_types_sem);
  43
  44 static const struct af_alg_type *alg_get_type(const char *name)
  45 {
  46         const struct af_alg_type *type = ERR_PTR(-ENOENT);
  47         struct alg_type_list *node;
  48
  49         down_read(&alg_types_sem);
  50         list_for_each_entry(node, &alg_types, list) {
  51                 if (strcmp(node->type->name, name))
  52                         continue;
  53
  54                 if (try_module_get(node->type->owner))
  55                         type = node->type;
  56                 break;
  57         }
  58         up_read(&alg_types_sem);
  59
  60         return type;
  61 }
  62
  63 int af_alg_register_type(const struct af_alg_type *type)
  64 {
  65         struct alg_type_list *node;
  66         int err = -EEXIST;
  67
  68         down_write(&alg_types_sem);
  69         list_for_each_entry(node, &alg_types, list) {
  70                 if (!strcmp(node->type->name, type->name))
  71                         goto unlock;
  72         }
  73
  74         node = kmalloc(sizeof(*node), GFP_KERNEL);
  75         err = -ENOMEM;
  76         if (!node)
  77                 goto unlock;
  78
  79         type->ops->owner = THIS_MODULE;
  80         if (type->ops_nokey)
  81                 type->ops_nokey->owner = THIS_MODULE;
  82         node->type = type;
  83         list_add(&node->list, &alg_types);
  84         err = 0;
  85
  86 unlock:
  87         up_write(&alg_types_sem);
  88
  89         return err;
  90 }
  91 EXPORT_SYMBOL_GPL(af_alg_register_type);
  92
  93 int af_alg_unregister_type(const struct af_alg_type *type)
  94 {
  95         struct alg_type_list *node;
  96         int err = -ENOENT;
  97
  98         down_write(&alg_types_sem);
  99         list_for_each_entry(node, &alg_types, list) {
 100                 if (strcmp(node->type->name, type->name))
 101                         continue;
 102
 103                 list_del(&node->list);
 104                 kfree(node);
 105                 err = 0;
 106                 break;
 107         }
 108         up_write(&alg_types_sem);
 109
 110         return err;
 111 }
 112 EXPORT_SYMBOL_GPL(af_alg_unregister_type);
 113
 114 static void alg_do_release(const struct af_alg_type *type, void *private)
 115 {
 116         if (!type)
 117                 return;
 118
 119         type->release(private);
 120         module_put(type->owner);
 121 }
 122
 123 int af_alg_release(struct socket *sock)
 124 {
 125         if (sock->sk)
 126                 sock_put(sock->sk);
 127         return 0;
 128 }
 129 EXPORT_SYMBOL_GPL(af_alg_release);
 130
 131 void af_alg_release_parent(struct sock *sk)
 132 {
 133         struct alg_sock *ask = alg_sk(sk);
 134         unsigned int nokey = ask->nokey_refcnt;
 135         bool last = nokey && !ask->refcnt;
 136
 137         sk = ask->parent;
 138         ask = alg_sk(sk);
 139
 140         lock_sock(sk);
 141         ask->nokey_refcnt -= nokey;
 142         if (!last)
 143                 last = !--ask->refcnt;
 144         release_sock(sk);
 145
 146         if (last)
 147                 sock_put(sk);
 148 }
 149 EXPORT_SYMBOL_GPL(af_alg_release_parent);
 150
 151 static int alg_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 152 {
 153         const u32 allowed = CRYPTO_ALG_KERN_DRIVER_ONLY;
 154         struct sock *sk = sock->sk;
 155         struct alg_sock *ask = alg_sk(sk);
 156         struct sockaddr_alg *sa = (void *)uaddr;
 157         const struct af_alg_type *type;
 158         void *private;
 159         int err;
 160
 161         if (sock->state == SS_CONNECTED)
 162                 return -EINVAL;
 163
 164         if (addr_len < sizeof(*sa))
 165                 return -EINVAL;
 166
 167         /* If caller uses non-allowed flag, return error. */
 168         if ((sa->salg_feat & ~allowed) || (sa->salg_mask & ~allowed))
 169                 return -EINVAL;
 170
 171         sa->salg_type[sizeof(sa->salg_type) - 1] = 0;
 172         sa->salg_name[sizeof(sa->salg_name) + addr_len - sizeof(*sa) - 1] = 0;
 173
 174         type = alg_get_type(sa->salg_type);
 175         if (IS_ERR(type) && PTR_ERR(type) == -ENOENT) {
 176                 request_module("algif-%s", sa->salg_type);
 177                 type = alg_get_type(sa->salg_type);
 178         }
 179
 180         if (IS_ERR(type))
 181                 return PTR_ERR(type);
 182
 183         private = type->bind(sa->salg_name, sa->salg_feat, sa->salg_mask);
 184         if (IS_ERR(private)) {
 185                 module_put(type->owner);
 186                 return PTR_ERR(private);
 187         }
 188
 189         err = -EBUSY;
 190         lock_sock(sk);
 191         if (ask->refcnt | ask->nokey_refcnt)
 192                 goto unlock;
 193
 194         swap(ask->type, type);
 195         swap(ask->private, private);
 196
 197         err = 0;
 198
 199 unlock:
 200         release_sock(sk);
 201
 202         alg_do_release(type, private);
 203
 204         return err;
 205 }
 206
 207 static int alg_setkey(struct sock *sk, char __user *ukey,
 208                       unsigned int keylen)
 209 {
 210         struct alg_sock *ask = alg_sk(sk);
 211         const struct af_alg_type *type = ask->type;
 212         u8 *key;
 213         int err;
 214
 215         key = sock_kmalloc(sk, keylen, GFP_KERNEL);
 216         if (!key)
 217                 return -ENOMEM;
 218
 219         err = -EFAULT;
 220         if (copy_from_user(key, ukey, keylen))
 221                 goto out;
 222
 223         err = type->setkey(ask->private, key, keylen);
 224
 225 out:
 226         sock_kzfree_s(sk, key, keylen);
 227
 228         return err;
 229 }
 230
 231 static int alg_setsockopt(struct socket *sock, int level, int optname,
 232                           char __user *optval, unsigned int optlen)
 233 {
 234         struct sock *sk = sock->sk;
 235         struct alg_sock *ask = alg_sk(sk);
 236         const struct af_alg_type *type;
 237         int err = -EBUSY;
 238
 239         lock_sock(sk);
 240         if (ask->refcnt)
 241                 goto unlock;
 242
 243         type = ask->type;
 244
 245         err = -ENOPROTOOPT;
 246         if (level != SOL_ALG || !type)
 247                 goto unlock;
 248
 249         switch (optname) {
 250         case ALG_SET_KEY:
 251                 if (sock->state == SS_CONNECTED)
 252                         goto unlock;
 253                 if (!type->setkey)
 254                         goto unlock;
 255
 256                 err = alg_setkey(sk, optval, optlen);
 257                 break;
 258         case ALG_SET_AEAD_AUTHSIZE:
 259                 if (sock->state == SS_CONNECTED)
 260                         goto unlock;
 261                 if (!type->setauthsize)
 262                         goto unlock;
 263                 err = type->setauthsize(ask->private, optlen);
 264         }
 265
 266 unlock:
 267         release_sock(sk);
 268
 269         return err;
 270 }
 271
 272 int af_alg_accept(struct sock *sk, struct socket *newsock, bool kern)
 273 {
 274         struct alg_sock *ask = alg_sk(sk);
 275         const struct af_alg_type *type;
 276         struct sock *sk2;
 277         unsigned int nokey;
 278         int err;
 279
 280         lock_sock(sk);
 281         type = ask->type;
 282
 283         err = -EINVAL;
 284         if (!type)
 285                 goto unlock;
 286
 287         sk2 = sk_alloc(sock_net(sk), PF_ALG, GFP_KERNEL, &alg_proto, kern);
 288         err = -ENOMEM;
 289         if (!sk2)
 290                 goto unlock;
 291
 292         sock_init_data(newsock, sk2);
 293         security_sock_graft(sk2, newsock);
 294         security_sk_clone(sk, sk2);
 295
 296         err = type->accept(ask->private, sk2);
 297
 298         nokey = err == -ENOKEY;
 299         if (nokey && type->accept_nokey)
 300                 err = type->accept_nokey(ask->private, sk2);
 301
 302         if (err)
 303                 goto unlock;
 304
 305         sk2->sk_family = PF_ALG;
 306
 307         if (nokey || !ask->refcnt++)
 308                 sock_hold(sk);
 309         ask->nokey_refcnt += nokey;
 310         alg_sk(sk2)->parent = sk;
 311         alg_sk(sk2)->type = type;
 312         alg_sk(sk2)->nokey_refcnt = nokey;
 313
 314         newsock->ops = type->ops;
 315         newsock->state = SS_CONNECTED;
 316
 317         if (nokey)
 318                 newsock->ops = type->ops_nokey;
 319
 320         err = 0;
 321
 322 unlock:
 323         release_sock(sk);
 324
 325         return err;
 326 }
 327 EXPORT_SYMBOL_GPL(af_alg_accept);
 328
 329 static int alg_accept(struct socket *sock, struct socket *newsock, int flags,
 330                       bool kern)
 331 {
 332         return af_alg_accept(sock->sk, newsock, kern);
 333 }
 334
 335 static const struct proto_ops alg_proto_ops = {
 336         .family         =       PF_ALG,
 337         .owner          =       THIS_MODULE,
 338
 339         .connect        =       sock_no_connect,
 340         .socketpair     =       sock_no_socketpair,
 341         .getname        =       sock_no_getname,
 342         .ioctl          =       sock_no_ioctl,
 343         .listen         =       sock_no_listen,
 344         .shutdown       =       sock_no_shutdown,
 345         .getsockopt     =       sock_no_getsockopt,
 346         .mmap           =       sock_no_mmap,
 347         .sendpage       =       sock_no_sendpage,
 348         .sendmsg        =       sock_no_sendmsg,
 349         .recvmsg        =       sock_no_recvmsg,
 350
 351         .bind           =       alg_bind,
 352         .release        =       af_alg_release,
 353         .setsockopt     =       alg_setsockopt,
 354         .accept         =       alg_accept,
 355 };
 356
 357 static void alg_sock_destruct(struct sock *sk)
 358 {
 359         struct alg_sock *ask = alg_sk(sk);
 360
 361         alg_do_release(ask->type, ask->private);
 362 }
 363
 364 static int alg_create(struct net *net, struct socket *sock, int protocol,
 365                       int kern)
 366 {
 367         struct sock *sk;
 368         int err;
 369
 370         if (sock->type != SOCK_SEQPACKET)
 371                 return -ESOCKTNOSUPPORT;
 372         if (protocol != 0)
 373                 return -EPROTONOSUPPORT;
 374
 375         err = -ENOMEM;
 376         sk = sk_alloc(net, PF_ALG, GFP_KERNEL, &alg_proto, kern);
 377         if (!sk)
 378                 goto out;
 379
 380         sock->ops = &alg_proto_ops;
 381         sock_init_data(sock, sk);
 382
 383         sk->sk_family = PF_ALG;
 384         sk->sk_destruct = alg_sock_destruct;
 385
 386         return 0;
 387 out:
 388         return err;
 389 }
 390
 391 static const struct net_proto_family alg_family = {
 392         .family =       PF_ALG,
 393         .create =       alg_create,
 394         .owner  =       THIS_MODULE,
 395 };
 396
 397 int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len)
 398 {
 399         size_t off;
 400         ssize_t n;
 401         int npages, i;
 402
 403         n = iov_iter_get_pages(iter, sgl->pages, len, ALG_MAX_PAGES, &off);
 404         if (n < 0)
 405                 return n;
 406
 407         npages = (off + n + PAGE_SIZE - 1) >> PAGE_SHIFT;
 408         if (WARN_ON(npages == 0))
 409                 return -EINVAL;
 410         /* Add one extra for linking */
 411         sg_init_table(sgl->sg, npages + 1);
 412
 413         for (i = 0, len = n; i < npages; i++) {
 414                 int plen = min_t(int, len, PAGE_SIZE - off);
 415
 416                 sg_set_page(sgl->sg + i, sgl->pages[i], plen, off);
 417
 418                 off = 0;
 419                 len -= plen;
 420         }
 421         sg_mark_end(sgl->sg + npages - 1);
 422         sgl->npages = npages;
 423
 424         return n;
 425 }
 426 EXPORT_SYMBOL_GPL(af_alg_make_sg);
 427
 428 void af_alg_link_sg(struct af_alg_sgl *sgl_prev, struct af_alg_sgl *sgl_new)
 429 {
 430         sg_unmark_end(sgl_prev->sg + sgl_prev->npages - 1);
 431         sg_chain(sgl_prev->sg, sgl_prev->npages + 1, sgl_new->sg);
 432 }
 433 EXPORT_SYMBOL_GPL(af_alg_link_sg);
 434
 435 void af_alg_free_sg(struct af_alg_sgl *sgl)
 436 {
 437         int i;
 438
 439         for (i = 0; i < sgl->npages; i++)
 440                 put_page(sgl->pages[i]);
 441 }
 442 EXPORT_SYMBOL_GPL(af_alg_free_sg);
 443
 444 int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con)
 445 {
 446         struct cmsghdr *cmsg;
 447
 448         for_each_cmsghdr(cmsg, msg) {
 449                 if (!CMSG_OK(msg, cmsg))
 450                         return -EINVAL;
 451                 if (cmsg->cmsg_level != SOL_ALG)
 452                         continue;
 453
 454                 switch (cmsg->cmsg_type) {
 455                 case ALG_SET_IV:
 456                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(*con->iv)))
 457                                 return -EINVAL;
 458                         con->iv = (void *)CMSG_DATA(cmsg);
 459                         if (cmsg->cmsg_len < CMSG_LEN(con->iv->ivlen +
 460                                                       sizeof(*con->iv)))
 461                                 return -EINVAL;
 462                         break;
 463
 464                 case ALG_SET_OP:
 465                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
 466                                 return -EINVAL;
 467                         con->op = *(u32 *)CMSG_DATA(cmsg);
 468                         break;
 469
 470                 case ALG_SET_AEAD_ASSOCLEN:
 471                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
 472                                 return -EINVAL;
 473                         con->aead_assoclen = *(u32 *)CMSG_DATA(cmsg);
 474                         break;
 475
 476                 default:
 477                         return -EINVAL;
 478                 }
 479         }
 480
 481         return 0;
 482 }
 483 EXPORT_SYMBOL_GPL(af_alg_cmsg_send);
 484
 485 /**
 486  * af_alg_alloc_tsgl - allocate the TX SGL
 487  *
 488  * @sk socket of connection to user space
 489  * @return: 0 upon success, < 0 upon error
 490  */
 491 int af_alg_alloc_tsgl(struct sock *sk)
 492 {
 493         struct alg_sock *ask = alg_sk(sk);
 494         struct af_alg_ctx *ctx = ask->private;
 495         struct af_alg_tsgl *sgl;
 496         struct scatterlist *sg = NULL;
 497
 498         sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl, list);
 499         if (!list_empty(&ctx->tsgl_list))
 500                 sg = sgl->sg;
 501
 502         if (!sg || sgl->cur >= MAX_SGL_ENTS) {
 503                 sgl = sock_kmalloc(sk,
 504                                    struct_size(sgl, sg, (MAX_SGL_ENTS + 1)),
 505                                    GFP_KERNEL);
 506                 if (!sgl)
 507                         return -ENOMEM;
 508
 509                 sg_init_table(sgl->sg, MAX_SGL_ENTS + 1);
 510                 sgl->cur = 0;
 511
 512                 if (sg)
 513                         sg_chain(sg, MAX_SGL_ENTS + 1, sgl->sg);
 514
 515                 list_add_tail(&sgl->list, &ctx->tsgl_list);
 516         }
 517
 518         return 0;
 519 }
 520 EXPORT_SYMBOL_GPL(af_alg_alloc_tsgl);
 521
 522 /**
 523  * aead_count_tsgl - Count number of TX SG entries
 524  *
 525  * The counting starts from the beginning of the SGL to @bytes. If
 526  * an offset is provided, the counting of the SG entries starts at the offset.
 527  *
 528  * @sk socket of connection to user space
 529  * @bytes Count the number of SG entries holding given number of bytes.
 530  * @offset Start the counting of SG entries from the given offset.
 531  * @return Number of TX SG entries found given the constraints
 532  */
 533 unsigned int af_alg_count_tsgl(struct sock *sk, size_t bytes, size_t offset)
 534 {
 535         struct alg_sock *ask = alg_sk(sk);
 536         struct af_alg_ctx *ctx = ask->private;
 537         struct af_alg_tsgl *sgl, *tmp;
 538         unsigned int i;
 539         unsigned int sgl_count = 0;
 540
 541         if (!bytes)
 542                 return 0;
 543
 544         list_for_each_entry_safe(sgl, tmp, &ctx->tsgl_list, list) {
 545                 struct scatterlist *sg = sgl->sg;
 546
 547                 for (i = 0; i < sgl->cur; i++) {
 548                         size_t bytes_count;
 549
 550                         /* Skip offset */
 551                         if (offset >= sg[i].length) {
 552                                 offset -= sg[i].length;
 553                                 bytes -= sg[i].length;
 554                                 continue;
 555                         }
 556
 557                         bytes_count = sg[i].length - offset;
 558
 559                         offset = 0;
 560                         sgl_count++;
 561
 562                         /* If we have seen requested number of bytes, stop */
 563                         if (bytes_count >= bytes)
 564                                 return sgl_count;
 565
 566                         bytes -= bytes_count;
 567                 }
 568         }
 569
 570         return sgl_count;
 571 }
 572 EXPORT_SYMBOL_GPL(af_alg_count_tsgl);
 573
 574 /**
 575  * aead_pull_tsgl - Release the specified buffers from TX SGL
 576  *
 577  * If @dst is non-null, reassign the pages to dst. The caller must release
 578  * the pages. If @dst_offset is given only reassign the pages to @dst starting
 579  * at the @dst_offset (byte). The caller must ensure that @dst is large
 580  * enough (e.g. by using af_alg_count_tsgl with the same offset).
 581  *
 582  * @sk socket of connection to user space
 583  * @used Number of bytes to pull from TX SGL
 584  * @dst If non-NULL, buffer is reassigned to dst SGL instead of releasing. The
 585  *      caller must release the buffers in dst.
 586  * @dst_offset Reassign the TX SGL from given offset. All buffers before
 587  *             reaching the offset is released.
 588  */
 589 void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst,
 590                       size_t dst_offset)
 591 {
 592         struct alg_sock *ask = alg_sk(sk);
 593         struct af_alg_ctx *ctx = ask->private;
 594         struct af_alg_tsgl *sgl;
 595         struct scatterlist *sg;
 596         unsigned int i, j = 0;
 597
 598         while (!list_empty(&ctx->tsgl_list)) {
 599                 sgl = list_first_entry(&ctx->tsgl_list, struct af_alg_tsgl,
 600                                        list);
 601                 sg = sgl->sg;
 602
 603                 for (i = 0; i < sgl->cur; i++) {
 604                         size_t plen = min_t(size_t, used, sg[i].length);
 605                         struct page *page = sg_page(sg + i);
 606
 607                         if (!page)
 608                                 continue;
 609
 610                         /*
 611                          * Assumption: caller created af_alg_count_tsgl(len)
 612                          * SG entries in dst.
 613                          */
 614                         if (dst) {
 615                                 if (dst_offset >= plen) {
 616                                         /* discard page before offset */
 617                                         dst_offset -= plen;
 618                                 } else {
 619                                         /* reassign page to dst after offset */
 620                                         get_page(page);
 621                                         sg_set_page(dst + j, page,
 622                                                     plen - dst_offset,
 623                                                     sg[i].offset + dst_offset);
 624                                         dst_offset = 0;
 625                                         j++;
 626                                 }
 627                         }
 628
 629                         sg[i].length -= plen;
 630                         sg[i].offset += plen;
 631
 632                         used -= plen;
 633                         ctx->used -= plen;
 634
 635                         if (sg[i].length)
 636                                 return;
 637
 638                         put_page(page);
 639                         sg_assign_page(sg + i, NULL);
 640                 }
 641
 642                 list_del(&sgl->list);
 643                 sock_kfree_s(sk, sgl, sizeof(*sgl) + sizeof(sgl->sg[0]) *
 644                                                      (MAX_SGL_ENTS + 1));
 645         }
 646
 647         if (!ctx->used)
 648                 ctx->merge = 0;
 649 }
 650 EXPORT_SYMBOL_GPL(af_alg_pull_tsgl);
 651
 652 /**
 653  * af_alg_free_areq_sgls - Release TX and RX SGLs of the request
 654  *
 655  * @areq Request holding the TX and RX SGL
 656  */
 657 void af_alg_free_areq_sgls(struct af_alg_async_req *areq)
 658 {
 659         struct sock *sk = areq->sk;
 660         struct alg_sock *ask = alg_sk(sk);
 661         struct af_alg_ctx *ctx = ask->private;
 662         struct af_alg_rsgl *rsgl, *tmp;
 663         struct scatterlist *tsgl;
 664         struct scatterlist *sg;
 665         unsigned int i;
 666
 667         list_for_each_entry_safe(rsgl, tmp, &areq->rsgl_list, list) {
 668                 atomic_sub(rsgl->sg_num_bytes, &ctx->rcvused);
 669                 af_alg_free_sg(&rsgl->sgl);
 670                 list_del(&rsgl->list);
 671                 if (rsgl != &areq->first_rsgl)
 672                         sock_kfree_s(sk, rsgl, sizeof(*rsgl));
 673         }
 674
 675         tsgl = areq->tsgl;
 676         if (tsgl) {
 677                 for_each_sg(tsgl, sg, areq->tsgl_entries, i) {
 678                         if (!sg_page(sg))
 679                                 continue;
 680                         put_page(sg_page(sg));
 681                 }
 682
 683                 sock_kfree_s(sk, tsgl, areq->tsgl_entries * sizeof(*tsgl));
 684         }
 685 }
 686 EXPORT_SYMBOL_GPL(af_alg_free_areq_sgls);
 687
 688 /**
 689  * af_alg_wait_for_wmem - wait for availability of writable memory
 690  *
 691  * @sk socket of connection to user space
 692  * @flags If MSG_DONTWAIT is set, then only report if function would sleep
 693  * @return 0 when writable memory is available, < 0 upon error
 694  */
 695 int af_alg_wait_for_wmem(struct sock *sk, unsigned int flags)
 696 {
 697         DEFINE_WAIT_FUNC(wait, woken_wake_function);
 698         int err = -ERESTARTSYS;
 699         long timeout;
 700
 701         if (flags & MSG_DONTWAIT)
 702                 return -EAGAIN;
 703
 704         sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 705
 706         add_wait_queue(sk_sleep(sk), &wait);
 707         for (;;) {
 708                 if (signal_pending(current))
 709                         break;
 710                 timeout = MAX_SCHEDULE_TIMEOUT;
 711                 if (sk_wait_event(sk, &timeout, af_alg_writable(sk), &wait)) {
 712                         err = 0;
 713                         break;
 714                 }
 715         }
 716         remove_wait_queue(sk_sleep(sk), &wait);
 717
 718         return err;
 719 }
 720 EXPORT_SYMBOL_GPL(af_alg_wait_for_wmem);
 721
 722 /**
 723  * af_alg_wmem_wakeup - wakeup caller when writable memory is available
 724  *
 725  * @sk socket of connection to user space
 726  */
 727 void af_alg_wmem_wakeup(struct sock *sk)
 728 {
 729         struct socket_wq *wq;
 730
 731         if (!af_alg_writable(sk))
 732                 return;
 733
 734         rcu_read_lock();
 735         wq = rcu_dereference(sk->sk_wq);
 736         if (skwq_has_sleeper(wq))
 737                 wake_up_interruptible_sync_poll(&wq->wait, EPOLLIN |
 738                                                            EPOLLRDNORM |
 739                                                            EPOLLRDBAND);
 740         sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
 741         rcu_read_unlock();
 742 }
 743 EXPORT_SYMBOL_GPL(af_alg_wmem_wakeup);
 744
 745 /**
 746  * af_alg_wait_for_data - wait for availability of TX data
 747  *
 748  * @sk socket of connection to user space
 749  * @flags If MSG_DONTWAIT is set, then only report if function would sleep
 750  * @return 0 when writable memory is available, < 0 upon error
 751  */
 752 int af_alg_wait_for_data(struct sock *sk, unsigned flags)
 753 {
 754         DEFINE_WAIT_FUNC(wait, woken_wake_function);
 755         struct alg_sock *ask = alg_sk(sk);
 756         struct af_alg_ctx *ctx = ask->private;
 757         long timeout;
 758         int err = -ERESTARTSYS;
 759
 760         if (flags & MSG_DONTWAIT)
 761                 return -EAGAIN;
 762
 763         sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 764
 765         add_wait_queue(sk_sleep(sk), &wait);
 766         for (;;) {
 767                 if (signal_pending(current))
 768                         break;
 769                 timeout = MAX_SCHEDULE_TIMEOUT;
 770                 if (sk_wait_event(sk, &timeout, (ctx->used || !ctx->more),
 771                                   &wait)) {
 772                         err = 0;
 773                         break;
 774                 }
 775         }
 776         remove_wait_queue(sk_sleep(sk), &wait);
 777
 778         sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 779
 780         return err;
 781 }
 782 EXPORT_SYMBOL_GPL(af_alg_wait_for_data);
 783
 784 /**
 785  * af_alg_data_wakeup - wakeup caller when new data can be sent to kernel
 786  *
 787  * @sk socket of connection to user space
 788  */
 789
 790 void af_alg_data_wakeup(struct sock *sk)
 791 {
 792         struct alg_sock *ask = alg_sk(sk);
 793         struct af_alg_ctx *ctx = ask->private;
 794         struct socket_wq *wq;
 795
 796         if (!ctx->used)
 797                 return;
 798
 799         rcu_read_lock();
 800         wq = rcu_dereference(sk->sk_wq);
 801         if (skwq_has_sleeper(wq))
 802                 wake_up_interruptible_sync_poll(&wq->wait, EPOLLOUT |
 803                                                            EPOLLRDNORM |
 804                                                            EPOLLRDBAND);
 805         sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
 806         rcu_read_unlock();
 807 }
 808 EXPORT_SYMBOL_GPL(af_alg_data_wakeup);
 809
 810 /**
 811  * af_alg_sendmsg - implementation of sendmsg system call handler
 812  *
 813  * The sendmsg system call handler obtains the user data and stores it
 814  * in ctx->tsgl_list. This implies allocation of the required numbers of
 815  * struct af_alg_tsgl.
 816  *
 817  * In addition, the ctx is filled with the information sent via CMSG.
 818  *
 819  * @sock socket of connection to user space
 820  * @msg message from user space
 821  * @size size of message from user space
 822  * @ivsize the size of the IV for the cipher operation to verify that the
 823  *         user-space-provided IV has the right size
 824  * @return the number of copied data upon success, < 0 upon error
 825  */
 826 int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
 827                    unsigned int ivsize)
 828 {
 829         struct sock *sk = sock->sk;
 830         struct alg_sock *ask = alg_sk(sk);
 831         struct af_alg_ctx *ctx = ask->private;
 832         struct af_alg_tsgl *sgl;
 833         struct af_alg_control con = {};
 834         long copied = 0;
 835         bool enc = 0;
 836         bool init = 0;
 837         int err = 0;
 838
 839         if (msg->msg_controllen) {
 840                 err = af_alg_cmsg_send(msg, &con);
 841                 if (err)
 842                         return err;
 843
 844                 init = 1;
 845                 switch (con.op) {
 846                 case ALG_OP_ENCRYPT:
 847                         enc = 1;
 848                         break;
 849                 case ALG_OP_DECRYPT:
 850                         enc = 0;
 851                         break;
 852                 default:
 853                         return -EINVAL;
 854                 }
 855
 856                 if (con.iv && con.iv->ivlen != ivsize)
 857                         return -EINVAL;
 858         }
 859
 860         lock_sock(sk);
 861         if (!ctx->more && ctx->used) {
 862                 err = -EINVAL;
 863                 goto unlock;
 864         }
 865
 866         if (init) {
 867                 ctx->enc = enc;
 868                 if (con.iv)
 869                         memcpy(ctx->iv, con.iv->iv, ivsize);
 870
 871                 ctx->aead_assoclen = con.aead_assoclen;
 872         }
 873
 874         while (size) {
 875                 struct scatterlist *sg;
 876                 size_t len = size;
 877                 size_t plen;
 878
 879                 /* use the existing memory in an allocated page */
 880                 if (ctx->merge) {
 881                         sgl = list_entry(ctx->tsgl_list.prev,
 882                                          struct af_alg_tsgl, list);
 883                         sg = sgl->sg + sgl->cur - 1;
 884                         len = min_t(size_t, len,
 885                                     PAGE_SIZE - sg->offset - sg->length);
 886
 887                         err = memcpy_from_msg(page_address(sg_page(sg)) +
 888                                               sg->offset + sg->length,
 889                                               msg, len);
 890                         if (err)
 891                                 goto unlock;
 892
 893                         sg->length += len;
 894                         ctx->merge = (sg->offset + sg->length) &
 895                                      (PAGE_SIZE - 1);
 896
 897                         ctx->used += len;
 898                         copied += len;
 899                         size -= len;
 900                         continue;
 901                 }
 902
 903                 if (!af_alg_writable(sk)) {
 904                         err = af_alg_wait_for_wmem(sk, msg->msg_flags);
 905                         if (err)
 906                                 goto unlock;
 907                 }
 908
 909                 /* allocate a new page */
 910                 len = min_t(unsigned long, len, af_alg_sndbuf(sk));
 911
 912                 err = af_alg_alloc_tsgl(sk);
 913                 if (err)
 914                         goto unlock;
 915
 916                 sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl,
 917                                  list);
 918                 sg = sgl->sg;
 919                 if (sgl->cur)
 920                         sg_unmark_end(sg + sgl->cur - 1);
 921
 922                 do {
 923                         unsigned int i = sgl->cur;
 924
 925                         plen = min_t(size_t, len, PAGE_SIZE);
 926
 927                         sg_assign_page(sg + i, alloc_page(GFP_KERNEL));
 928                         if (!sg_page(sg + i)) {
 929                                 err = -ENOMEM;
 930                                 goto unlock;
 931                         }
 932
 933                         err = memcpy_from_msg(page_address(sg_page(sg + i)),
 934                                               msg, plen);
 935                         if (err) {
 936                                 __free_page(sg_page(sg + i));
 937                                 sg_assign_page(sg + i, NULL);
 938                                 goto unlock;
 939                         }
 940
 941                         sg[i].length = plen;
 942                         len -= plen;
 943                         ctx->used += plen;
 944                         copied += plen;
 945                         size -= plen;
 946                         sgl->cur++;
 947                 } while (len && sgl->cur < MAX_SGL_ENTS);
 948
 949                 if (!size)
 950                         sg_mark_end(sg + sgl->cur - 1);
 951
 952                 ctx->merge = plen & (PAGE_SIZE - 1);
 953         }
 954
 955         err = 0;
 956
 957         ctx->more = msg->msg_flags & MSG_MORE;
 958
 959 unlock:
 960         af_alg_data_wakeup(sk);
 961         release_sock(sk);
 962
 963         return copied ?: err;
 964 }
 965 EXPORT_SYMBOL_GPL(af_alg_sendmsg);
 966
 967 /**
 968  * af_alg_sendpage - sendpage system call handler
 969  *
 970  * This is a generic implementation of sendpage to fill ctx->tsgl_list.
 971  */
 972 ssize_t af_alg_sendpage(struct socket *sock, struct page *page,
 973                         int offset, size_t size, int flags)
 974 {
 975         struct sock *sk = sock->sk;
 976         struct alg_sock *ask = alg_sk(sk);
 977         struct af_alg_ctx *ctx = ask->private;
 978         struct af_alg_tsgl *sgl;
 979         int err = -EINVAL;
 980
 981         if (flags & MSG_SENDPAGE_NOTLAST)
 982                 flags |= MSG_MORE;
 983
 984         lock_sock(sk);
 985         if (!ctx->more && ctx->used)
 986                 goto unlock;
 987
 988         if (!size)
 989                 goto done;
 990
 991         if (!af_alg_writable(sk)) {
 992                 err = af_alg_wait_for_wmem(sk, flags);
 993                 if (err)
 994                         goto unlock;
 995         }
 996
 997         err = af_alg_alloc_tsgl(sk);
 998         if (err)
 999                 goto unlock;
1000
1001         ctx->merge = 0;
1002         sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl, list);
1003
1004         if (sgl->cur)
1005                 sg_unmark_end(sgl->sg + sgl->cur - 1);
1006
1007         sg_mark_end(sgl->sg + sgl->cur);
1008
1009         get_page(page);
1010         sg_set_page(sgl->sg + sgl->cur, page, size, offset);
1011         sgl->cur++;
1012         ctx->used += size;
1013
1014 done:
1015         ctx->more = flags & MSG_MORE;
1016
1017 unlock:
1018         af_alg_data_wakeup(sk);
1019         release_sock(sk);
1020
1021         return err ?: size;
1022 }
1023 EXPORT_SYMBOL_GPL(af_alg_sendpage);
1024
1025 /**
1026  * af_alg_free_resources - release resources required for crypto request
1027  */
1028 void af_alg_free_resources(struct af_alg_async_req *areq)
1029 {
1030         struct sock *sk = areq->sk;
1031
1032         af_alg_free_areq_sgls(areq);
1033         sock_kfree_s(sk, areq, areq->areqlen);
1034 }
1035 EXPORT_SYMBOL_GPL(af_alg_free_resources);
1036
1037 /**
1038  * af_alg_async_cb - AIO callback handler
1039  *
1040  * This handler cleans up the struct af_alg_async_req upon completion of the
1041  * AIO operation.
1042  *
1043  * The number of bytes to be generated with the AIO operation must be set
1044  * in areq->outlen before the AIO callback handler is invoked.
1045  */
1046 void af_alg_async_cb(struct crypto_async_request *_req, int err)
1047 {
1048         struct af_alg_async_req *areq = _req->data;
1049         struct sock *sk = areq->sk;
1050         struct kiocb *iocb = areq->iocb;
1051         unsigned int resultlen;
1052
1053         /* Buffer size written by crypto operation. */
1054         resultlen = areq->outlen;
1055
1056         af_alg_free_resources(areq);
1057         sock_put(sk);
1058
1059         iocb->ki_complete(iocb, err ? err : resultlen, 0);
1060 }
1061 EXPORT_SYMBOL_GPL(af_alg_async_cb);
1062
1063 /**
1064  * af_alg_poll - poll system call handler
1065  */
1066 __poll_t af_alg_poll(struct file *file, struct socket *sock,
1067                          poll_table *wait)
1068 {
1069         struct sock *sk = sock->sk;
1070         struct alg_sock *ask = alg_sk(sk);
1071         struct af_alg_ctx *ctx = ask->private;
1072         __poll_t mask;
1073
1074         sock_poll_wait(file, wait);
1075         mask = 0;
1076
1077         if (!ctx->more || ctx->used)
1078                 mask |= EPOLLIN | EPOLLRDNORM;
1079
1080         if (af_alg_writable(sk))
1081                 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
1082
1083         return mask;
1084 }
1085 EXPORT_SYMBOL_GPL(af_alg_poll);
1086
1087 /**
1088  * af_alg_alloc_areq - allocate struct af_alg_async_req
1089  *
1090  * @sk socket of connection to user space
1091  * @areqlen size of struct af_alg_async_req + crypto_*_reqsize
1092  * @return allocated data structure or ERR_PTR upon error
1093  */
1094 struct af_alg_async_req *af_alg_alloc_areq(struct sock *sk,
1095                                            unsigned int areqlen)
1096 {
1097         struct af_alg_async_req *areq = sock_kmalloc(sk, areqlen, GFP_KERNEL);
1098
1099         if (unlikely(!areq))
1100                 return ERR_PTR(-ENOMEM);
1101
1102         areq->areqlen = areqlen;
1103         areq->sk = sk;
1104         areq->last_rsgl = NULL;
1105         INIT_LIST_HEAD(&areq->rsgl_list);
1106         areq->tsgl = NULL;
1107         areq->tsgl_entries = 0;
1108
1109         return areq;
1110 }
1111 EXPORT_SYMBOL_GPL(af_alg_alloc_areq);
1112
1113 /**
1114  * af_alg_get_rsgl - create the RX SGL for the output data from the crypto
1115  *                   operation
1116  *
1117  * @sk socket of connection to user space
1118  * @msg user space message
1119  * @flags flags used to invoke recvmsg with
1120  * @areq instance of the cryptographic request that will hold the RX SGL
1121  * @maxsize maximum number of bytes to be pulled from user space
1122  * @outlen number of bytes in the RX SGL
1123  * @return 0 on success, < 0 upon error
1124  */
1125 int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags,
1126                     struct af_alg_async_req *areq, size_t maxsize,
1127                     size_t *outlen)
1128 {
1129         struct alg_sock *ask = alg_sk(sk);
1130         struct af_alg_ctx *ctx = ask->private;
1131         size_t len = 0;
1132
1133         while (maxsize > len && msg_data_left(msg)) {
1134                 struct af_alg_rsgl *rsgl;
1135                 size_t seglen;
1136                 int err;
1137
1138                 /* limit the amount of readable buffers */
1139                 if (!af_alg_readable(sk))
1140                         break;
1141
1142                 seglen = min_t(size_t, (maxsize - len),
1143                                msg_data_left(msg));
1144
1145                 if (list_empty(&areq->rsgl_list)) {
1146                         rsgl = &areq->first_rsgl;
1147                 } else {
1148                         rsgl = sock_kmalloc(sk, sizeof(*rsgl), GFP_KERNEL);
1149                         if (unlikely(!rsgl))
1150                                 return -ENOMEM;
1151                 }
1152
1153                 rsgl->sgl.npages = 0;
1154                 list_add_tail(&rsgl->list, &areq->rsgl_list);
1155
1156                 /* make one iovec available as scatterlist */
1157                 err = af_alg_make_sg(&rsgl->sgl, &msg->msg_iter, seglen);
1158                 if (err < 0) {
1159                         rsgl->sg_num_bytes = 0;
1160                         return err;
1161                 }
1162
1163                 /* chain the new scatterlist with previous one */
1164                 if (areq->last_rsgl)
1165                         af_alg_link_sg(&areq->last_rsgl->sgl, &rsgl->sgl);
1166
1167                 areq->last_rsgl = rsgl;
1168                 len += err;
1169                 atomic_add(err, &ctx->rcvused);
1170                 rsgl->sg_num_bytes = err;
1171                 iov_iter_advance(&msg->msg_iter, err);
1172         }
1173
1174         *outlen = len;
1175         return 0;
1176 }
1177 EXPORT_SYMBOL_GPL(af_alg_get_rsgl);
1178
1179 static int __init af_alg_init(void)
1180 {
1181         int err = proto_register(&alg_proto, 0);
1182
1183         if (err)
1184                 goto out;
1185
1186         err = sock_register(&alg_family);
1187         if (err != 0)
1188                 goto out_unregister_proto;
1189
1190 out:
1191         return err;
1192
1193 out_unregister_proto:
1194         proto_unregister(&alg_proto);
1195         goto out;
1196 }
1197
1198 static void __exit af_alg_exit(void)
1199 {
1200         sock_unregister(PF_ALG);
1201         proto_unregister(&alg_proto);
1202 }
1203
1204 module_init(af_alg_init);
1205 module_exit(af_alg_exit);
1206 MODULE_LICENSE("GPL");
1207 MODULE_ALIAS_NETPROTO(AF_ALG);