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