linux/crypto/af_alg.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * af_alg: User-space algorithm interface
   4 *
   5 * This file provides the user-space API for algorithms.
   6 *
   7 * Copyright (c) 2010 Herbert Xu <herbert@gondor.apana.org.au>
   8 */
   9
  10#include <linux/atomic.h>
  11#include <crypto/if_alg.h>
  12#include <linux/crypto.h>
  13#include <linux/init.h>
  14#include <linux/kernel.h>
  15#include <linux/list.h>
  16#include <linux/module.h>
  17#include <linux/net.h>
  18#include <linux/rwsem.h>
  19#include <linux/sched.h>
  20#include <linux/sched/signal.h>
  21#include <linux/security.h>
  22
  23struct alg_type_list {
  24        const struct af_alg_type *type;
  25        struct list_head list;
  26};
  27
  28static atomic_long_t alg_memory_allocated;
  29
  30static struct proto alg_proto = {
  31        .name                   = "ALG",
  32        .owner                  = THIS_MODULE,
  33        .memory_allocated       = &alg_memory_allocated,
  34        .obj_size               = sizeof(struct alg_sock),
  35};
  36
  37static LIST_HEAD(alg_types);
  38static DECLARE_RWSEM(alg_types_sem);
  39
  40static const struct af_alg_type *alg_get_type(const char *name)
  41{
  42        const struct af_alg_type *type = ERR_PTR(-ENOENT);
  43        struct alg_type_list *node;
  44
  45        down_read(&alg_types_sem);
  46        list_for_each_entry(node, &alg_types, list) {
  47                if (strcmp(node->type->name, name))
  48                        continue;
  49
  50                if (try_module_get(node->type->owner))
  51                        type = node->type;
  52                break;
  53        }
  54        up_read(&alg_types_sem);
  55
  56        return type;
  57}
  58
  59int af_alg_register_type(const struct af_alg_type *type)
  60{
  61        struct alg_type_list *node;
  62        int err = -EEXIST;
  63
  64        down_write(&alg_types_sem);
  65        list_for_each_entry(node, &alg_types, list) {
  66                if (!strcmp(node->type->name, type->name))
  67                        goto unlock;
  68        }
  69
  70        node = kmalloc(sizeof(*node), GFP_KERNEL);
  71        err = -ENOMEM;
  72        if (!node)
  73                goto unlock;
  74
  75        type->ops->owner = THIS_MODULE;
  76        if (type->ops_nokey)
  77                type->ops_nokey->owner = THIS_MODULE;
  78        node->type = type;
  79        list_add(&node->list, &alg_types);
  80        err = 0;
  81
  82unlock:
  83        up_write(&alg_types_sem);
  84
  85        return err;
  86}
  87EXPORT_SYMBOL_GPL(af_alg_register_type);
  88
  89int af_alg_unregister_type(const struct af_alg_type *type)
  90{
  91        struct alg_type_list *node;
  92        int err = -ENOENT;
  93
  94        down_write(&alg_types_sem);
  95        list_for_each_entry(node, &alg_types, list) {
  96                if (strcmp(node->type->name, type->name))
  97                        continue;
  98
  99                list_del(&node->list);
 100                kfree(node);
 101                err = 0;
 102                break;
 103        }
 104        up_write(&alg_types_sem);
 105
 106        return err;
 107}
 108EXPORT_SYMBOL_GPL(af_alg_unregister_type);
 109
 110static void alg_do_release(const struct af_alg_type *type, void *private)
 111{
 112        if (!type)
 113                return;
 114
 115        type->release(private);
 116        module_put(type->owner);
 117}
 118
 119int af_alg_release(struct socket *sock)
 120{
 121        if (sock->sk) {
 122                sock_put(sock->sk);
 123                sock->sk = NULL;
 124        }
 125        return 0;
 126}
 127EXPORT_SYMBOL_GPL(af_alg_release);
 128
 129void af_alg_release_parent(struct sock *sk)
 130{
 131        struct alg_sock *ask = alg_sk(sk);
 132        unsigned int nokey = atomic_read(&ask->nokey_refcnt);
 133
 134        sk = ask->parent;
 135        ask = alg_sk(sk);
 136
 137        if (nokey)
 138                atomic_dec(&ask->nokey_refcnt);
 139
 140        if (atomic_dec_and_test(&ask->refcnt))
 141                sock_put(sk);
 142}
 143EXPORT_SYMBOL_GPL(af_alg_release_parent);
 144
 145static int alg_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 146{
 147        const u32 allowed = CRYPTO_ALG_KERN_DRIVER_ONLY;
 148        struct sock *sk = sock->sk;
 149        struct alg_sock *ask = alg_sk(sk);
 150        struct sockaddr_alg_new *sa = (void *)uaddr;
 151        const struct af_alg_type *type;
 152        void *private;
 153        int err;
 154
 155        if (sock->state == SS_CONNECTED)
 156                return -EINVAL;
 157
 158        BUILD_BUG_ON(offsetof(struct sockaddr_alg_new, salg_name) !=
 159                     offsetof(struct sockaddr_alg, salg_name));
 160        BUILD_BUG_ON(offsetof(struct sockaddr_alg, salg_name) != sizeof(*sa));
 161
 162        if (addr_len < sizeof(*sa) + 1)
 163                return -EINVAL;
 164
 165        /* If caller uses non-allowed flag, return error. */
 166        if ((sa->salg_feat & ~allowed) || (sa->salg_mask & ~allowed))
 167                return -EINVAL;
 168
 169        sa->salg_type[sizeof(sa->salg_type) - 1] = 0;
 170        sa->salg_name[addr_len - sizeof(*sa) - 1] = 0;
 171
 172        type = alg_get_type(sa->salg_type);
 173        if (PTR_ERR(type) == -ENOENT) {
 174                request_module("algif-%s", sa->salg_type);
 175                type = alg_get_type(sa->salg_type);
 176        }
 177
 178        if (IS_ERR(type))
 179                return PTR_ERR(type);
 180
 181        private = type->bind(sa->salg_name, sa->salg_feat, sa->salg_mask);
 182        if (IS_ERR(private)) {
 183                module_put(type->owner);
 184                return PTR_ERR(private);
 185        }
 186
 187        err = -EBUSY;
 188        lock_sock(sk);
 189        if (atomic_read(&ask->refcnt))
 190                goto unlock;
 191
 192        swap(ask->type, type);
 193        swap(ask->private, private);
 194
 195        err = 0;
 196
 197unlock:
 198        release_sock(sk);
 199
 200        alg_do_release(type, private);
 201
 202        return err;
 203}
 204
 205static int alg_setkey(struct sock *sk, sockptr_t ukey, unsigned int keylen)
 206{
 207        struct alg_sock *ask = alg_sk(sk);
 208        const struct af_alg_type *type = ask->type;
 209        u8 *key;
 210        int err;
 211
 212        key = sock_kmalloc(sk, keylen, GFP_KERNEL);
 213        if (!key)
 214                return -ENOMEM;
 215
 216        err = -EFAULT;
 217        if (copy_from_sockptr(key, ukey, keylen))
 218                goto out;
 219
 220        err = type->setkey(ask->private, key, keylen);
 221
 222out:
 223        sock_kzfree_s(sk, key, keylen);
 224
 225        return err;
 226}
 227
 228static int alg_setsockopt(struct socket *sock, int level, int optname,
 229                          sockptr_t optval, unsigned int optlen)
 230{
 231        struct sock *sk = sock->sk;
 232        struct alg_sock *ask = alg_sk(sk);
 233        const struct af_alg_type *type;
 234        int err = -EBUSY;
 235
 236        lock_sock(sk);
 237        if (atomic_read(&ask->refcnt) != atomic_read(&ask->nokey_refcnt))
 238                goto unlock;
 239
 240        type = ask->type;
 241
 242        err = -ENOPROTOOPT;
 243        if (level != SOL_ALG || !type)
 244                goto unlock;
 245
 246        switch (optname) {
 247        case ALG_SET_KEY:
 248                if (sock->state == SS_CONNECTED)
 249                        goto unlock;
 250                if (!type->setkey)
 251                        goto unlock;
 252
 253                err = alg_setkey(sk, optval, optlen);
 254                break;
 255        case ALG_SET_AEAD_AUTHSIZE:
 256                if (sock->state == SS_CONNECTED)
 257                        goto unlock;
 258                if (!type->setauthsize)
 259                        goto unlock;
 260                err = type->setauthsize(ask->private, optlen);
 261                break;
 262        case ALG_SET_DRBG_ENTROPY:
 263                if (sock->state == SS_CONNECTED)
 264                        goto unlock;
 265                if (!type->setentropy)
 266                        goto unlock;
 267
 268                err = type->setentropy(ask->private, optval, optlen);
 269        }
 270
 271unlock:
 272        release_sock(sk);
 273
 274        return err;
 275}
 276
 277int af_alg_accept(struct sock *sk, struct socket *newsock, bool kern)
 278{
 279        struct alg_sock *ask = alg_sk(sk);
 280        const struct af_alg_type *type;
 281        struct sock *sk2;
 282        unsigned int nokey;
 283        int err;
 284
 285        lock_sock(sk);
 286        type = ask->type;
 287
 288        err = -EINVAL;
 289        if (!type)
 290                goto unlock;
 291
 292        sk2 = sk_alloc(sock_net(sk), PF_ALG, GFP_KERNEL, &alg_proto, kern);
 293        err = -ENOMEM;
 294        if (!sk2)
 295                goto unlock;
 296
 297        sock_init_data(newsock, sk2);
 298        security_sock_graft(sk2, newsock);
 299        security_sk_clone(sk, sk2);
 300
 301        /*
 302         * newsock->ops assigned here to allow type->accept call to override
 303         * them when required.
 304         */
 305        newsock->ops = type->ops;
 306        err = type->accept(ask->private, sk2);
 307
 308        nokey = err == -ENOKEY;
 309        if (nokey && type->accept_nokey)
 310                err = type->accept_nokey(ask->private, sk2);
 311
 312        if (err)
 313                goto unlock;
 314
 315        if (atomic_inc_return_relaxed(&ask->refcnt) == 1)
 316                sock_hold(sk);
 317        if (nokey) {
 318                atomic_inc(&ask->nokey_refcnt);
 319                atomic_set(&alg_sk(sk2)->nokey_refcnt, 1);
 320        }
 321        alg_sk(sk2)->parent = sk;
 322        alg_sk(sk2)->type = type;
 323
 324        newsock->state = SS_CONNECTED;
 325
 326        if (nokey)
 327                newsock->ops = type->ops_nokey;
 328
 329        err = 0;
 330
 331unlock:
 332        release_sock(sk);
 333
 334        return err;
 335}
 336EXPORT_SYMBOL_GPL(af_alg_accept);
 337
 338static int alg_accept(struct socket *sock, struct socket *newsock, int flags,
 339                      bool kern)
 340{
 341        return af_alg_accept(sock->sk, newsock, kern);
 342}
 343
 344static const struct proto_ops alg_proto_ops = {
 345        .family         =       PF_ALG,
 346        .owner          =       THIS_MODULE,
 347
 348        .connect        =       sock_no_connect,
 349        .socketpair     =       sock_no_socketpair,
 350        .getname        =       sock_no_getname,
 351        .ioctl          =       sock_no_ioctl,
 352        .listen         =       sock_no_listen,
 353        .shutdown       =       sock_no_shutdown,
 354        .mmap           =       sock_no_mmap,
 355        .sendpage       =       sock_no_sendpage,
 356        .sendmsg        =       sock_no_sendmsg,
 357        .recvmsg        =       sock_no_recvmsg,
 358
 359        .bind           =       alg_bind,
 360        .release        =       af_alg_release,
 361        .setsockopt     =       alg_setsockopt,
 362        .accept         =       alg_accept,
 363};
 364
 365static void alg_sock_destruct(struct sock *sk)
 366{
 367        struct alg_sock *ask = alg_sk(sk);
 368
 369        alg_do_release(ask->type, ask->private);
 370}
 371
 372static int alg_create(struct net *net, struct socket *sock, int protocol,
 373                      int kern)
 374{
 375        struct sock *sk;
 376        int err;
 377
 378        if (sock->type != SOCK_SEQPACKET)
 379                return -ESOCKTNOSUPPORT;
 380        if (protocol != 0)
 381                return -EPROTONOSUPPORT;
 382
 383        err = -ENOMEM;
 384        sk = sk_alloc(net, PF_ALG, GFP_KERNEL, &alg_proto, kern);
 385        if (!sk)
 386                goto out;
 387
 388        sock->ops = &alg_proto_ops;
 389        sock_init_data(sock, sk);
 390
 391        sk->sk_destruct = alg_sock_destruct;
 392
 393        return 0;
 394out:
 395        return err;
 396}
 397
 398static const struct net_proto_family alg_family = {
 399        .family =       PF_ALG,
 400        .create =       alg_create,
 401        .owner  =       THIS_MODULE,
 402};
 403
 404int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len)
 405{
 406        size_t off;
 407        ssize_t n;
 408        int npages, i;
 409
 410        n = iov_iter_get_pages(iter, sgl->pages, len, ALG_MAX_PAGES, &off);
 411        if (n < 0)
 412                return n;
 413
 414        npages = DIV_ROUND_UP(off + n, PAGE_SIZE);
 415        if (WARN_ON(npages == 0))
 416                return -EINVAL;
 417        /* Add one extra for linking */
 418        sg_init_table(sgl->sg, npages + 1);
 419
 420        for (i = 0, len = n; i < npages; i++) {
 421                int plen = min_t(int, len, PAGE_SIZE - off);
 422
 423                sg_set_page(sgl->sg + i, sgl->pages[i], plen, off);
 424
 425                off = 0;
 426                len -= plen;
 427        }
 428        sg_mark_end(sgl->sg + npages - 1);
 429        sgl->npages = npages;
 430
 431        return n;
 432}
 433EXPORT_SYMBOL_GPL(af_alg_make_sg);
 434
 435static void af_alg_link_sg(struct af_alg_sgl *sgl_prev,
 436                           struct af_alg_sgl *sgl_new)
 437{
 438        sg_unmark_end(sgl_prev->sg + sgl_prev->npages - 1);
 439        sg_chain(sgl_prev->sg, sgl_prev->npages + 1, sgl_new->sg);
 440}
 441
 442void af_alg_free_sg(struct af_alg_sgl *sgl)
 443{
 444        int i;
 445
 446        for (i = 0; i < sgl->npages; i++)
 447                put_page(sgl->pages[i]);
 448}
 449EXPORT_SYMBOL_GPL(af_alg_free_sg);
 450
 451static int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con)
 452{
 453        struct cmsghdr *cmsg;
 454
 455        for_each_cmsghdr(cmsg, msg) {
 456                if (!CMSG_OK(msg, cmsg))
 457                        return -EINVAL;
 458                if (cmsg->cmsg_level != SOL_ALG)
 459                        continue;
 460
 461                switch (cmsg->cmsg_type) {
 462                case ALG_SET_IV:
 463                        if (cmsg->cmsg_len < CMSG_LEN(sizeof(*con->iv)))
 464                                return -EINVAL;
 465                        con->iv = (void *)CMSG_DATA(cmsg);
 466                        if (cmsg->cmsg_len < CMSG_LEN(con->iv->ivlen +
 467                                                      sizeof(*con->iv)))
 468                                return -EINVAL;
 469                        break;
 470
 471                case ALG_SET_OP:
 472                        if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
 473                                return -EINVAL;
 474                        con->op = *(u32 *)CMSG_DATA(cmsg);
 475                        break;
 476
 477                case ALG_SET_AEAD_ASSOCLEN:
 478                        if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
 479                                return -EINVAL;
 480                        con->aead_assoclen = *(u32 *)CMSG_DATA(cmsg);
 481                        break;
 482
 483                default:
 484                        return -EINVAL;
 485                }
 486        }
 487
 488        return 0;
 489}
 490
 491/**
 492 * af_alg_alloc_tsgl - allocate the TX SGL
 493 *
 494 * @sk: socket of connection to user space
 495 * Return: 0 upon success, < 0 upon error
 496 */
 497static int af_alg_alloc_tsgl(struct sock *sk)
 498{
 499        struct alg_sock *ask = alg_sk(sk);
 500        struct af_alg_ctx *ctx = ask->private;
 501        struct af_alg_tsgl *sgl;
 502        struct scatterlist *sg = NULL;
 503
 504        sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl, list);
 505        if (!list_empty(&ctx->tsgl_list))
 506                sg = sgl->sg;
 507
 508        if (!sg || sgl->cur >= MAX_SGL_ENTS) {
 509                sgl = sock_kmalloc(sk,
 510                                   struct_size(sgl, sg, (MAX_SGL_ENTS + 1)),
 511                                   GFP_KERNEL);
 512                if (!sgl)
 513                        return -ENOMEM;
 514
 515                sg_init_table(sgl->sg, MAX_SGL_ENTS + 1);
 516                sgl->cur = 0;
 517
 518                if (sg)
 519                        sg_chain(sg, MAX_SGL_ENTS + 1, sgl->sg);
 520
 521                list_add_tail(&sgl->list, &ctx->tsgl_list);
 522        }
 523
 524        return 0;
 525}
 526
 527/**
 528 * af_alg_count_tsgl - Count number of TX SG entries
 529 *
 530 * The counting starts from the beginning of the SGL to @bytes. If
 531 * an @offset is provided, the counting of the SG entries starts at the @offset.
 532 *
 533 * @sk: socket of connection to user space
 534 * @bytes: Count the number of SG entries holding given number of bytes.
 535 * @offset: Start the counting of SG entries from the given offset.
 536 * Return: Number of TX SG entries found given the constraints
 537 */
 538unsigned int af_alg_count_tsgl(struct sock *sk, size_t bytes, size_t offset)
 539{
 540        const struct alg_sock *ask = alg_sk(sk);
 541        const struct af_alg_ctx *ctx = ask->private;
 542        const struct af_alg_tsgl *sgl;
 543        unsigned int i;
 544        unsigned int sgl_count = 0;
 545
 546        if (!bytes)
 547                return 0;
 548
 549        list_for_each_entry(sgl, &ctx->tsgl_list, list) {
 550                const struct scatterlist *sg = sgl->sg;
 551
 552                for (i = 0; i < sgl->cur; i++) {
 553                        size_t bytes_count;
 554
 555                        /* Skip offset */
 556                        if (offset >= sg[i].length) {
 557                                offset -= sg[i].length;
 558                                bytes -= sg[i].length;
 559                                continue;
 560                        }
 561
 562                        bytes_count = sg[i].length - offset;
 563
 564                        offset = 0;
 565                        sgl_count++;
 566
 567                        /* If we have seen requested number of bytes, stop */
 568                        if (bytes_count >= bytes)
 569                                return sgl_count;
 570
 571                        bytes -= bytes_count;
 572                }
 573        }
 574
 575        return sgl_count;
 576}
 577EXPORT_SYMBOL_GPL(af_alg_count_tsgl);
 578
 579/**
 580 * af_alg_pull_tsgl - Release the specified buffers from TX SGL
 581 *
 582 * If @dst is non-null, reassign the pages to @dst. The caller must release
 583 * the pages. If @dst_offset is given only reassign the pages to @dst starting
 584 * at the @dst_offset (byte). The caller must ensure that @dst is large
 585 * enough (e.g. by using af_alg_count_tsgl with the same offset).
 586 *
 587 * @sk: socket of connection to user space
 588 * @used: Number of bytes to pull from TX SGL
 589 * @dst: If non-NULL, buffer is reassigned to dst SGL instead of releasing. The
 590 *       caller must release the buffers in dst.
 591 * @dst_offset: Reassign the TX SGL from given offset. All buffers before
 592 *              reaching the offset is released.
 593 */
 594void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst,
 595                      size_t dst_offset)
 596{
 597        struct alg_sock *ask = alg_sk(sk);
 598        struct af_alg_ctx *ctx = ask->private;
 599        struct af_alg_tsgl *sgl;
 600        struct scatterlist *sg;
 601        unsigned int i, j = 0;
 602
 603        while (!list_empty(&ctx->tsgl_list)) {
 604                sgl = list_first_entry(&ctx->tsgl_list, struct af_alg_tsgl,
 605                                       list);
 606                sg = sgl->sg;
 607
 608                for (i = 0; i < sgl->cur; i++) {
 609                        size_t plen = min_t(size_t, used, sg[i].length);
 610                        struct page *page = sg_page(sg + i);
 611
 612                        if (!page)
 613                                continue;
 614
 615                        /*
 616                         * Assumption: caller created af_alg_count_tsgl(len)
 617                         * SG entries in dst.
 618                         */
 619                        if (dst) {
 620                                if (dst_offset >= plen) {
 621                                        /* discard page before offset */
 622                                        dst_offset -= plen;
 623                                } else {
 624                                        /* reassign page to dst after offset */
 625                                        get_page(page);
 626                                        sg_set_page(dst + j, page,
 627                                                    plen - dst_offset,
 628                                                    sg[i].offset + dst_offset);
 629                                        dst_offset = 0;
 630                                        j++;
 631                                }
 632                        }
 633
 634                        sg[i].length -= plen;
 635                        sg[i].offset += plen;
 636
 637                        used -= plen;
 638                        ctx->used -= plen;
 639
 640                        if (sg[i].length)
 641                                return;
 642
 643                        put_page(page);
 644                        sg_assign_page(sg + i, NULL);
 645                }
 646
 647                list_del(&sgl->list);
 648                sock_kfree_s(sk, sgl, struct_size(sgl, sg, MAX_SGL_ENTS + 1));
 649        }
 650
 651        if (!ctx->used)
 652                ctx->merge = 0;
 653        ctx->init = ctx->more;
 654}
 655EXPORT_SYMBOL_GPL(af_alg_pull_tsgl);
 656
 657/**
 658 * af_alg_free_areq_sgls - Release TX and RX SGLs of the request
 659 *
 660 * @areq: Request holding the TX and RX SGL
 661 */
 662static void af_alg_free_areq_sgls(struct af_alg_async_req *areq)
 663{
 664        struct sock *sk = areq->sk;
 665        struct alg_sock *ask = alg_sk(sk);
 666        struct af_alg_ctx *ctx = ask->private;
 667        struct af_alg_rsgl *rsgl, *tmp;
 668        struct scatterlist *tsgl;
 669        struct scatterlist *sg;
 670        unsigned int i;
 671
 672        list_for_each_entry_safe(rsgl, tmp, &areq->rsgl_list, list) {
 673                atomic_sub(rsgl->sg_num_bytes, &ctx->rcvused);
 674                af_alg_free_sg(&rsgl->sgl);
 675                list_del(&rsgl->list);
 676                if (rsgl != &areq->first_rsgl)
 677                        sock_kfree_s(sk, rsgl, sizeof(*rsgl));
 678        }
 679
 680        tsgl = areq->tsgl;
 681        if (tsgl) {
 682                for_each_sg(tsgl, sg, areq->tsgl_entries, i) {
 683                        if (!sg_page(sg))
 684                                continue;
 685                        put_page(sg_page(sg));
 686                }
 687
 688                sock_kfree_s(sk, tsgl, areq->tsgl_entries * sizeof(*tsgl));
 689        }
 690}
 691
 692/**
 693 * af_alg_wait_for_wmem - wait for availability of writable memory
 694 *
 695 * @sk: socket of connection to user space
 696 * @flags: If MSG_DONTWAIT is set, then only report if function would sleep
 697 * Return: 0 when writable memory is available, < 0 upon error
 698 */
 699static int af_alg_wait_for_wmem(struct sock *sk, unsigned int flags)
 700{
 701        DEFINE_WAIT_FUNC(wait, woken_wake_function);
 702        int err = -ERESTARTSYS;
 703        long timeout;
 704
 705        if (flags & MSG_DONTWAIT)
 706                return -EAGAIN;
 707
 708        sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk);
 709
 710        add_wait_queue(sk_sleep(sk), &wait);
 711        for (;;) {
 712                if (signal_pending(current))
 713                        break;
 714                timeout = MAX_SCHEDULE_TIMEOUT;
 715                if (sk_wait_event(sk, &timeout, af_alg_writable(sk), &wait)) {
 716                        err = 0;
 717                        break;
 718                }
 719        }
 720        remove_wait_queue(sk_sleep(sk), &wait);
 721
 722        return err;
 723}
 724
 725/**
 726 * af_alg_wmem_wakeup - wakeup caller when writable memory is available
 727 *
 728 * @sk: socket of connection to user space
 729 */
 730void af_alg_wmem_wakeup(struct sock *sk)
 731{
 732        struct socket_wq *wq;
 733
 734        if (!af_alg_writable(sk))
 735                return;
 736
 737        rcu_read_lock();
 738        wq = rcu_dereference(sk->sk_wq);
 739        if (skwq_has_sleeper(wq))
 740                wake_up_interruptible_sync_poll(&wq->wait, EPOLLIN |
 741                                                           EPOLLRDNORM |
 742                                                           EPOLLRDBAND);
 743        sk_wake_async(sk, SOCK_WAKE_WAITD, POLL_IN);
 744        rcu_read_unlock();
 745}
 746EXPORT_SYMBOL_GPL(af_alg_wmem_wakeup);
 747
 748/**
 749 * af_alg_wait_for_data - wait for availability of TX data
 750 *
 751 * @sk: socket of connection to user space
 752 * @flags: If MSG_DONTWAIT is set, then only report if function would sleep
 753 * @min: Set to minimum request size if partial requests are allowed.
 754 * Return: 0 when writable memory is available, < 0 upon error
 755 */
 756int af_alg_wait_for_data(struct sock *sk, unsigned flags, unsigned min)
 757{
 758        DEFINE_WAIT_FUNC(wait, woken_wake_function);
 759        struct alg_sock *ask = alg_sk(sk);
 760        struct af_alg_ctx *ctx = ask->private;
 761        long timeout;
 762        int err = -ERESTARTSYS;
 763
 764        if (flags & MSG_DONTWAIT)
 765                return -EAGAIN;
 766
 767        sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 768
 769        add_wait_queue(sk_sleep(sk), &wait);
 770        for (;;) {
 771                if (signal_pending(current))
 772                        break;
 773                timeout = MAX_SCHEDULE_TIMEOUT;
 774                if (sk_wait_event(sk, &timeout,
 775                                  ctx->init && (!ctx->more ||
 776                                                (min && ctx->used >= min)),
 777                                  &wait)) {
 778                        err = 0;
 779                        break;
 780                }
 781        }
 782        remove_wait_queue(sk_sleep(sk), &wait);
 783
 784        sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
 785
 786        return err;
 787}
 788EXPORT_SYMBOL_GPL(af_alg_wait_for_data);
 789
 790/**
 791 * af_alg_data_wakeup - wakeup caller when new data can be sent to kernel
 792 *
 793 * @sk: socket of connection to user space
 794 */
 795static void af_alg_data_wakeup(struct sock *sk)
 796{
 797        struct alg_sock *ask = alg_sk(sk);
 798        struct af_alg_ctx *ctx = ask->private;
 799        struct socket_wq *wq;
 800
 801        if (!ctx->used)
 802                return;
 803
 804        rcu_read_lock();
 805        wq = rcu_dereference(sk->sk_wq);
 806        if (skwq_has_sleeper(wq))
 807                wake_up_interruptible_sync_poll(&wq->wait, EPOLLOUT |
 808                                                           EPOLLRDNORM |
 809                                                           EPOLLRDBAND);
 810        sk_wake_async(sk, SOCK_WAKE_SPACE, POLL_OUT);
 811        rcu_read_unlock();
 812}
 813
 814/**
 815 * af_alg_sendmsg - implementation of sendmsg system call handler
 816 *
 817 * The sendmsg system call handler obtains the user data and stores it
 818 * in ctx->tsgl_list. This implies allocation of the required numbers of
 819 * struct af_alg_tsgl.
 820 *
 821 * In addition, the ctx is filled with the information sent via CMSG.
 822 *
 823 * @sock: socket of connection to user space
 824 * @msg: message from user space
 825 * @size: size of message from user space
 826 * @ivsize: the size of the IV for the cipher operation to verify that the
 827 *         user-space-provided IV has the right size
 828 * Return: the number of copied data upon success, < 0 upon error
 829 */
 830int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size,
 831                   unsigned int ivsize)
 832{
 833        struct sock *sk = sock->sk;
 834        struct alg_sock *ask = alg_sk(sk);
 835        struct af_alg_ctx *ctx = ask->private;
 836        struct af_alg_tsgl *sgl;
 837        struct af_alg_control con = {};
 838        long copied = 0;
 839        bool enc = false;
 840        bool init = false;
 841        int err = 0;
 842
 843        if (msg->msg_controllen) {
 844                err = af_alg_cmsg_send(msg, &con);
 845                if (err)
 846                        return err;
 847
 848                init = true;
 849                switch (con.op) {
 850                case ALG_OP_ENCRYPT:
 851                        enc = true;
 852                        break;
 853                case ALG_OP_DECRYPT:
 854                        enc = false;
 855                        break;
 856                default:
 857                        return -EINVAL;
 858                }
 859
 860                if (con.iv && con.iv->ivlen != ivsize)
 861                        return -EINVAL;
 862        }
 863
 864        lock_sock(sk);
 865        if (ctx->init && !ctx->more) {
 866                if (ctx->used) {
 867                        err = -EINVAL;
 868                        goto unlock;
 869                }
 870
 871                pr_info_once(
 872                        "%s sent an empty control message without MSG_MORE.\n",
 873                        current->comm);
 874        }
 875        ctx->init = true;
 876
 877        if (init) {
 878                ctx->enc = enc;
 879                if (con.iv)
 880                        memcpy(ctx->iv, con.iv->iv, ivsize);
 881
 882                ctx->aead_assoclen = con.aead_assoclen;
 883        }
 884
 885        while (size) {
 886                struct scatterlist *sg;
 887                size_t len = size;
 888                size_t plen;
 889
 890                /* use the existing memory in an allocated page */
 891                if (ctx->merge) {
 892                        sgl = list_entry(ctx->tsgl_list.prev,
 893                                         struct af_alg_tsgl, list);
 894                        sg = sgl->sg + sgl->cur - 1;
 895                        len = min_t(size_t, len,
 896                                    PAGE_SIZE - sg->offset - sg->length);
 897
 898                        err = memcpy_from_msg(page_address(sg_page(sg)) +
 899                                              sg->offset + sg->length,
 900                                              msg, len);
 901                        if (err)
 902                                goto unlock;
 903
 904                        sg->length += len;
 905                        ctx->merge = (sg->offset + sg->length) &
 906                                     (PAGE_SIZE - 1);
 907
 908                        ctx->used += len;
 909                        copied += len;
 910                        size -= len;
 911                        continue;
 912                }
 913
 914                if (!af_alg_writable(sk)) {
 915                        err = af_alg_wait_for_wmem(sk, msg->msg_flags);
 916                        if (err)
 917                                goto unlock;
 918                }
 919
 920                /* allocate a new page */
 921                len = min_t(unsigned long, len, af_alg_sndbuf(sk));
 922
 923                err = af_alg_alloc_tsgl(sk);
 924                if (err)
 925                        goto unlock;
 926
 927                sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl,
 928                                 list);
 929                sg = sgl->sg;
 930                if (sgl->cur)
 931                        sg_unmark_end(sg + sgl->cur - 1);
 932
 933                do {
 934                        unsigned int i = sgl->cur;
 935
 936                        plen = min_t(size_t, len, PAGE_SIZE);
 937
 938                        sg_assign_page(sg + i, alloc_page(GFP_KERNEL));
 939                        if (!sg_page(sg + i)) {
 940                                err = -ENOMEM;
 941                                goto unlock;
 942                        }
 943
 944                        err = memcpy_from_msg(page_address(sg_page(sg + i)),
 945                                              msg, plen);
 946                        if (err) {
 947                                __free_page(sg_page(sg + i));
 948                                sg_assign_page(sg + i, NULL);
 949                                goto unlock;
 950                        }
 951
 952                        sg[i].length = plen;
 953                        len -= plen;
 954                        ctx->used += plen;
 955                        copied += plen;
 956                        size -= plen;
 957                        sgl->cur++;
 958                } while (len && sgl->cur < MAX_SGL_ENTS);
 959
 960                if (!size)
 961                        sg_mark_end(sg + sgl->cur - 1);
 962
 963                ctx->merge = plen & (PAGE_SIZE - 1);
 964        }
 965
 966        err = 0;
 967
 968        ctx->more = msg->msg_flags & MSG_MORE;
 969
 970unlock:
 971        af_alg_data_wakeup(sk);
 972        release_sock(sk);
 973
 974        return copied ?: err;
 975}
 976EXPORT_SYMBOL_GPL(af_alg_sendmsg);
 977
 978/**
 979 * af_alg_sendpage - sendpage system call handler
 980 * @sock: socket of connection to user space to write to
 981 * @page: data to send
 982 * @offset: offset into page to begin sending
 983 * @size: length of data
 984 * @flags: message send/receive flags
 985 *
 986 * This is a generic implementation of sendpage to fill ctx->tsgl_list.
 987 */
 988ssize_t af_alg_sendpage(struct socket *sock, struct page *page,
 989                        int offset, size_t size, int flags)
 990{
 991        struct sock *sk = sock->sk;
 992        struct alg_sock *ask = alg_sk(sk);
 993        struct af_alg_ctx *ctx = ask->private;
 994        struct af_alg_tsgl *sgl;
 995        int err = -EINVAL;
 996
 997        if (flags & MSG_SENDPAGE_NOTLAST)
 998                flags |= MSG_MORE;
 999
1000        lock_sock(sk);
1001        if (!ctx->more && ctx->used)
1002                goto unlock;
1003
1004        if (!size)
1005                goto done;
1006
1007        if (!af_alg_writable(sk)) {
1008                err = af_alg_wait_for_wmem(sk, flags);
1009                if (err)
1010                        goto unlock;
1011        }
1012
1013        err = af_alg_alloc_tsgl(sk);
1014        if (err)
1015                goto unlock;
1016
1017        ctx->merge = 0;
1018        sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl, list);
1019
1020        if (sgl->cur)
1021                sg_unmark_end(sgl->sg + sgl->cur - 1);
1022
1023        sg_mark_end(sgl->sg + sgl->cur);
1024
1025        get_page(page);
1026        sg_set_page(sgl->sg + sgl->cur, page, size, offset);
1027        sgl->cur++;
1028        ctx->used += size;
1029
1030done:
1031        ctx->more = flags & MSG_MORE;
1032
1033unlock:
1034        af_alg_data_wakeup(sk);
1035        release_sock(sk);
1036
1037        return err ?: size;
1038}
1039EXPORT_SYMBOL_GPL(af_alg_sendpage);
1040
1041/**
1042 * af_alg_free_resources - release resources required for crypto request
1043 * @areq: Request holding the TX and RX SGL
1044 */
1045void af_alg_free_resources(struct af_alg_async_req *areq)
1046{
1047        struct sock *sk = areq->sk;
1048
1049        af_alg_free_areq_sgls(areq);
1050        sock_kfree_s(sk, areq, areq->areqlen);
1051}
1052EXPORT_SYMBOL_GPL(af_alg_free_resources);
1053
1054/**
1055 * af_alg_async_cb - AIO callback handler
1056 * @_req: async request info
1057 * @err: if non-zero, error result to be returned via ki_complete();
1058 *       otherwise return the AIO output length via ki_complete().
1059 *
1060 * This handler cleans up the struct af_alg_async_req upon completion of the
1061 * AIO operation.
1062 *
1063 * The number of bytes to be generated with the AIO operation must be set
1064 * in areq->outlen before the AIO callback handler is invoked.
1065 */
1066void af_alg_async_cb(struct crypto_async_request *_req, int err)
1067{
1068        struct af_alg_async_req *areq = _req->data;
1069        struct sock *sk = areq->sk;
1070        struct kiocb *iocb = areq->iocb;
1071        unsigned int resultlen;
1072
1073        /* Buffer size written by crypto operation. */
1074        resultlen = areq->outlen;
1075
1076        af_alg_free_resources(areq);
1077        sock_put(sk);
1078
1079        iocb->ki_complete(iocb, err ? err : (int)resultlen, 0);
1080}
1081EXPORT_SYMBOL_GPL(af_alg_async_cb);
1082
1083/**
1084 * af_alg_poll - poll system call handler
1085 * @file: file pointer
1086 * @sock: socket to poll
1087 * @wait: poll_table
1088 */
1089__poll_t af_alg_poll(struct file *file, struct socket *sock,
1090                         poll_table *wait)
1091{
1092        struct sock *sk = sock->sk;
1093        struct alg_sock *ask = alg_sk(sk);
1094        struct af_alg_ctx *ctx = ask->private;
1095        __poll_t mask;
1096
1097        sock_poll_wait(file, sock, wait);
1098        mask = 0;
1099
1100        if (!ctx->more || ctx->used)
1101                mask |= EPOLLIN | EPOLLRDNORM;
1102
1103        if (af_alg_writable(sk))
1104                mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
1105
1106        return mask;
1107}
1108EXPORT_SYMBOL_GPL(af_alg_poll);
1109
1110/**
1111 * af_alg_alloc_areq - allocate struct af_alg_async_req
1112 *
1113 * @sk: socket of connection to user space
1114 * @areqlen: size of struct af_alg_async_req + crypto_*_reqsize
1115 * Return: allocated data structure or ERR_PTR upon error
1116 */
1117struct af_alg_async_req *af_alg_alloc_areq(struct sock *sk,
1118                                           unsigned int areqlen)
1119{
1120        struct af_alg_async_req *areq = sock_kmalloc(sk, areqlen, GFP_KERNEL);
1121
1122        if (unlikely(!areq))
1123                return ERR_PTR(-ENOMEM);
1124
1125        areq->areqlen = areqlen;
1126        areq->sk = sk;
1127        areq->last_rsgl = NULL;
1128        INIT_LIST_HEAD(&areq->rsgl_list);
1129        areq->tsgl = NULL;
1130        areq->tsgl_entries = 0;
1131
1132        return areq;
1133}
1134EXPORT_SYMBOL_GPL(af_alg_alloc_areq);
1135
1136/**
1137 * af_alg_get_rsgl - create the RX SGL for the output data from the crypto
1138 *                   operation
1139 *
1140 * @sk: socket of connection to user space
1141 * @msg: user space message
1142 * @flags: flags used to invoke recvmsg with
1143 * @areq: instance of the cryptographic request that will hold the RX SGL
1144 * @maxsize: maximum number of bytes to be pulled from user space
1145 * @outlen: number of bytes in the RX SGL
1146 * Return: 0 on success, < 0 upon error
1147 */
1148int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags,
1149                    struct af_alg_async_req *areq, size_t maxsize,
1150                    size_t *outlen)
1151{
1152        struct alg_sock *ask = alg_sk(sk);
1153        struct af_alg_ctx *ctx = ask->private;
1154        size_t len = 0;
1155
1156        while (maxsize > len && msg_data_left(msg)) {
1157                struct af_alg_rsgl *rsgl;
1158                size_t seglen;
1159                int err;
1160
1161                /* limit the amount of readable buffers */
1162                if (!af_alg_readable(sk))
1163                        break;
1164
1165                seglen = min_t(size_t, (maxsize - len),
1166                               msg_data_left(msg));
1167
1168                if (list_empty(&areq->rsgl_list)) {
1169                        rsgl = &areq->first_rsgl;
1170                } else {
1171                        rsgl = sock_kmalloc(sk, sizeof(*rsgl), GFP_KERNEL);
1172                        if (unlikely(!rsgl))
1173                                return -ENOMEM;
1174                }
1175
1176                rsgl->sgl.npages = 0;
1177                list_add_tail(&rsgl->list, &areq->rsgl_list);
1178
1179                /* make one iovec available as scatterlist */
1180                err = af_alg_make_sg(&rsgl->sgl, &msg->msg_iter, seglen);
1181                if (err < 0) {
1182                        rsgl->sg_num_bytes = 0;
1183                        return err;
1184                }
1185
1186                /* chain the new scatterlist with previous one */
1187                if (areq->last_rsgl)
1188                        af_alg_link_sg(&areq->last_rsgl->sgl, &rsgl->sgl);
1189
1190                areq->last_rsgl = rsgl;
1191                len += err;
1192                atomic_add(err, &ctx->rcvused);
1193                rsgl->sg_num_bytes = err;
1194                iov_iter_advance(&msg->msg_iter, err);
1195        }
1196
1197        *outlen = len;
1198        return 0;
1199}
1200EXPORT_SYMBOL_GPL(af_alg_get_rsgl);
1201
1202static int __init af_alg_init(void)
1203{
1204        int err = proto_register(&alg_proto, 0);
1205
1206        if (err)
1207                goto out;
1208
1209        err = sock_register(&alg_family);
1210        if (err != 0)
1211                goto out_unregister_proto;
1212
1213out:
1214        return err;
1215
1216out_unregister_proto:
1217        proto_unregister(&alg_proto);
1218        goto out;
1219}
1220
1221static void __exit af_alg_exit(void)
1222{
1223        sock_unregister(PF_ALG);
1224        proto_unregister(&alg_proto);
1225}
1226
1227module_init(af_alg_init);
1228module_exit(af_alg_exit);
1229MODULE_LICENSE("GPL");
1230MODULE_ALIAS_NETPROTO(AF_ALG);
1231
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