linux/crypto/af_alg.c
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   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
  25struct alg_type_list {
  26        const struct af_alg_type *type;
  27        struct list_head list;
  28};
  29
  30static atomic_long_t alg_memory_allocated;
  31
  32static struct proto alg_proto = {
  33        .name                   = "ALG",
  34        .owner                  = THIS_MODULE,
  35        .memory_allocated       = &alg_memory_allocated,
  36        .obj_size               = sizeof(struct alg_sock),
  37};
  38
  39static LIST_HEAD(alg_types);
  40static DECLARE_RWSEM(alg_types_sem);
  41
  42static const struct af_alg_type *alg_get_type(const char *name)
  43{
  44        const struct af_alg_type *type = ERR_PTR(-ENOENT);
  45        struct alg_type_list *node;
  46
  47        down_read(&alg_types_sem);
  48        list_for_each_entry(node, &alg_types, list) {
  49                if (strcmp(node->type->name, name))
  50                        continue;
  51
  52                if (try_module_get(node->type->owner))
  53                        type = node->type;
  54                break;
  55        }
  56        up_read(&alg_types_sem);
  57
  58        return type;
  59}
  60
  61int af_alg_register_type(const struct af_alg_type *type)
  62{
  63        struct alg_type_list *node;
  64        int err = -EEXIST;
  65
  66        down_write(&alg_types_sem);
  67        list_for_each_entry(node, &alg_types, list) {
  68                if (!strcmp(node->type->name, type->name))
  69                        goto unlock;
  70        }
  71
  72        node = kmalloc(sizeof(*node), GFP_KERNEL);
  73        err = -ENOMEM;
  74        if (!node)
  75                goto unlock;
  76
  77        type->ops->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        return 0;
 124}
 125EXPORT_SYMBOL_GPL(af_alg_release);
 126
 127static int alg_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 128{
 129        struct sock *sk = sock->sk;
 130        struct alg_sock *ask = alg_sk(sk);
 131        struct sockaddr_alg *sa = (void *)uaddr;
 132        const struct af_alg_type *type;
 133        void *private;
 134
 135        if (sock->state == SS_CONNECTED)
 136                return -EINVAL;
 137
 138        if (addr_len != sizeof(*sa))
 139                return -EINVAL;
 140
 141        sa->salg_type[sizeof(sa->salg_type) - 1] = 0;
 142        sa->salg_name[sizeof(sa->salg_name) - 1] = 0;
 143
 144        type = alg_get_type(sa->salg_type);
 145        if (IS_ERR(type) && PTR_ERR(type) == -ENOENT) {
 146                request_module("algif-%s", sa->salg_type);
 147                type = alg_get_type(sa->salg_type);
 148        }
 149
 150        if (IS_ERR(type))
 151                return PTR_ERR(type);
 152
 153        private = type->bind(sa->salg_name, sa->salg_feat, sa->salg_mask);
 154        if (IS_ERR(private)) {
 155                module_put(type->owner);
 156                return PTR_ERR(private);
 157        }
 158
 159        lock_sock(sk);
 160
 161        swap(ask->type, type);
 162        swap(ask->private, private);
 163
 164        release_sock(sk);
 165
 166        alg_do_release(type, private);
 167
 168        return 0;
 169}
 170
 171static int alg_setkey(struct sock *sk, char __user *ukey,
 172                      unsigned int keylen)
 173{
 174        struct alg_sock *ask = alg_sk(sk);
 175        const struct af_alg_type *type = ask->type;
 176        u8 *key;
 177        int err;
 178
 179        key = sock_kmalloc(sk, keylen, GFP_KERNEL);
 180        if (!key)
 181                return -ENOMEM;
 182
 183        err = -EFAULT;
 184        if (copy_from_user(key, ukey, keylen))
 185                goto out;
 186
 187        err = type->setkey(ask->private, key, keylen);
 188
 189out:
 190        sock_kfree_s(sk, key, keylen);
 191
 192        return err;
 193}
 194
 195static int alg_setsockopt(struct socket *sock, int level, int optname,
 196                          char __user *optval, unsigned int optlen)
 197{
 198        struct sock *sk = sock->sk;
 199        struct alg_sock *ask = alg_sk(sk);
 200        const struct af_alg_type *type;
 201        int err = -ENOPROTOOPT;
 202
 203        lock_sock(sk);
 204        type = ask->type;
 205
 206        if (level != SOL_ALG || !type)
 207                goto unlock;
 208
 209        switch (optname) {
 210        case ALG_SET_KEY:
 211                if (sock->state == SS_CONNECTED)
 212                        goto unlock;
 213                if (!type->setkey)
 214                        goto unlock;
 215
 216                err = alg_setkey(sk, optval, optlen);
 217        }
 218
 219unlock:
 220        release_sock(sk);
 221
 222        return err;
 223}
 224
 225int af_alg_accept(struct sock *sk, struct socket *newsock)
 226{
 227        struct alg_sock *ask = alg_sk(sk);
 228        const struct af_alg_type *type;
 229        struct sock *sk2;
 230        int err;
 231
 232        lock_sock(sk);
 233        type = ask->type;
 234
 235        err = -EINVAL;
 236        if (!type)
 237                goto unlock;
 238
 239        sk2 = sk_alloc(sock_net(sk), PF_ALG, GFP_KERNEL, &alg_proto);
 240        err = -ENOMEM;
 241        if (!sk2)
 242                goto unlock;
 243
 244        sock_init_data(newsock, sk2);
 245        sock_graft(sk2, newsock);
 246
 247        err = type->accept(ask->private, sk2);
 248        if (err) {
 249                sk_free(sk2);
 250                goto unlock;
 251        }
 252
 253        sk2->sk_family = PF_ALG;
 254
 255        sock_hold(sk);
 256        alg_sk(sk2)->parent = sk;
 257        alg_sk(sk2)->type = type;
 258
 259        newsock->ops = type->ops;
 260        newsock->state = SS_CONNECTED;
 261
 262        err = 0;
 263
 264unlock:
 265        release_sock(sk);
 266
 267        return err;
 268}
 269EXPORT_SYMBOL_GPL(af_alg_accept);
 270
 271static int alg_accept(struct socket *sock, struct socket *newsock, int flags)
 272{
 273        return af_alg_accept(sock->sk, newsock);
 274}
 275
 276static const struct proto_ops alg_proto_ops = {
 277        .family         =       PF_ALG,
 278        .owner          =       THIS_MODULE,
 279
 280        .connect        =       sock_no_connect,
 281        .socketpair     =       sock_no_socketpair,
 282        .getname        =       sock_no_getname,
 283        .ioctl          =       sock_no_ioctl,
 284        .listen         =       sock_no_listen,
 285        .shutdown       =       sock_no_shutdown,
 286        .getsockopt     =       sock_no_getsockopt,
 287        .mmap           =       sock_no_mmap,
 288        .sendpage       =       sock_no_sendpage,
 289        .sendmsg        =       sock_no_sendmsg,
 290        .recvmsg        =       sock_no_recvmsg,
 291        .poll           =       sock_no_poll,
 292
 293        .bind           =       alg_bind,
 294        .release        =       af_alg_release,
 295        .setsockopt     =       alg_setsockopt,
 296        .accept         =       alg_accept,
 297};
 298
 299static void alg_sock_destruct(struct sock *sk)
 300{
 301        struct alg_sock *ask = alg_sk(sk);
 302
 303        alg_do_release(ask->type, ask->private);
 304}
 305
 306static int alg_create(struct net *net, struct socket *sock, int protocol,
 307                      int kern)
 308{
 309        struct sock *sk;
 310        int err;
 311
 312        if (sock->type != SOCK_SEQPACKET)
 313                return -ESOCKTNOSUPPORT;
 314        if (protocol != 0)
 315                return -EPROTONOSUPPORT;
 316
 317        err = -ENOMEM;
 318        sk = sk_alloc(net, PF_ALG, GFP_KERNEL, &alg_proto);
 319        if (!sk)
 320                goto out;
 321
 322        sock->ops = &alg_proto_ops;
 323        sock_init_data(sock, sk);
 324
 325        sk->sk_family = PF_ALG;
 326        sk->sk_destruct = alg_sock_destruct;
 327
 328        return 0;
 329out:
 330        return err;
 331}
 332
 333static const struct net_proto_family alg_family = {
 334        .family =       PF_ALG,
 335        .create =       alg_create,
 336        .owner  =       THIS_MODULE,
 337};
 338
 339int af_alg_make_sg(struct af_alg_sgl *sgl, void __user *addr, int len,
 340                   int write)
 341{
 342        unsigned long from = (unsigned long)addr;
 343        unsigned long npages;
 344        unsigned off;
 345        int err;
 346        int i;
 347
 348        err = -EFAULT;
 349        if (!access_ok(write ? VERIFY_READ : VERIFY_WRITE, addr, len))
 350                goto out;
 351
 352        off = from & ~PAGE_MASK;
 353        npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
 354        if (npages > ALG_MAX_PAGES)
 355                npages = ALG_MAX_PAGES;
 356
 357        err = get_user_pages_fast(from, npages, write, sgl->pages);
 358        if (err < 0)
 359                goto out;
 360
 361        npages = err;
 362        err = -EINVAL;
 363        if (WARN_ON(npages == 0))
 364                goto out;
 365
 366        err = 0;
 367
 368        sg_init_table(sgl->sg, npages);
 369
 370        for (i = 0; i < npages; i++) {
 371                int plen = min_t(int, len, PAGE_SIZE - off);
 372
 373                sg_set_page(sgl->sg + i, sgl->pages[i], plen, off);
 374
 375                off = 0;
 376                len -= plen;
 377                err += plen;
 378        }
 379
 380out:
 381        return err;
 382}
 383EXPORT_SYMBOL_GPL(af_alg_make_sg);
 384
 385void af_alg_free_sg(struct af_alg_sgl *sgl)
 386{
 387        int i;
 388
 389        i = 0;
 390        do {
 391                put_page(sgl->pages[i]);
 392        } while (!sg_is_last(sgl->sg + (i++)));
 393}
 394EXPORT_SYMBOL_GPL(af_alg_free_sg);
 395
 396int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con)
 397{
 398        struct cmsghdr *cmsg;
 399
 400        for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
 401                if (!CMSG_OK(msg, cmsg))
 402                        return -EINVAL;
 403                if (cmsg->cmsg_level != SOL_ALG)
 404                        continue;
 405
 406                switch(cmsg->cmsg_type) {
 407                case ALG_SET_IV:
 408                        if (cmsg->cmsg_len < CMSG_LEN(sizeof(*con->iv)))
 409                                return -EINVAL;
 410                        con->iv = (void *)CMSG_DATA(cmsg);
 411                        if (cmsg->cmsg_len < CMSG_LEN(con->iv->ivlen +
 412                                                      sizeof(*con->iv)))
 413                                return -EINVAL;
 414                        break;
 415
 416                case ALG_SET_OP:
 417                        if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
 418                                return -EINVAL;
 419                        con->op = *(u32 *)CMSG_DATA(cmsg);
 420                        break;
 421
 422                default:
 423                        return -EINVAL;
 424                }
 425        }
 426
 427        return 0;
 428}
 429EXPORT_SYMBOL_GPL(af_alg_cmsg_send);
 430
 431int af_alg_wait_for_completion(int err, struct af_alg_completion *completion)
 432{
 433        switch (err) {
 434        case -EINPROGRESS:
 435        case -EBUSY:
 436                wait_for_completion(&completion->completion);
 437                INIT_COMPLETION(completion->completion);
 438                err = completion->err;
 439                break;
 440        };
 441
 442        return err;
 443}
 444EXPORT_SYMBOL_GPL(af_alg_wait_for_completion);
 445
 446void af_alg_complete(struct crypto_async_request *req, int err)
 447{
 448        struct af_alg_completion *completion = req->data;
 449
 450        completion->err = err;
 451        complete(&completion->completion);
 452}
 453EXPORT_SYMBOL_GPL(af_alg_complete);
 454
 455static int __init af_alg_init(void)
 456{
 457        int err = proto_register(&alg_proto, 0);
 458
 459        if (err)
 460                goto out;
 461
 462        err = sock_register(&alg_family);
 463        if (err != 0)
 464                goto out_unregister_proto;
 465
 466out:
 467        return err;
 468
 469out_unregister_proto:
 470        proto_unregister(&alg_proto);
 471        goto out;
 472}
 473
 474static void __exit af_alg_exit(void)
 475{
 476        sock_unregister(PF_ALG);
 477        proto_unregister(&alg_proto);
 478}
 479
 480module_init(af_alg_init);
 481module_exit(af_alg_exit);
 482MODULE_LICENSE("GPL");
 483MODULE_ALIAS_NETPROTO(AF_ALG);
 484
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