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/security.h>
  25
  26 struct alg_type_list {
  27         const struct af_alg_type *type;
  28         struct list_head list;
  29 };
  30
  31 static atomic_long_t alg_memory_allocated;
  32
  33 static struct proto alg_proto = {
  34         .name                   = "ALG",
  35         .owner                  = THIS_MODULE,
  36         .memory_allocated       = &alg_memory_allocated,
  37         .obj_size               = sizeof(struct alg_sock),
  38 };
  39
  40 static LIST_HEAD(alg_types);
  41 static DECLARE_RWSEM(alg_types_sem);
  42
  43 static const struct af_alg_type *alg_get_type(const char *name)
  44 {
  45         const struct af_alg_type *type = ERR_PTR(-ENOENT);
  46         struct alg_type_list *node;
  47
  48         down_read(&alg_types_sem);
  49         list_for_each_entry(node, &alg_types, list) {
  50                 if (strcmp(node->type->name, name))
  51                         continue;
  52
  53                 if (try_module_get(node->type->owner))
  54                         type = node->type;
  55                 break;
  56         }
  57         up_read(&alg_types_sem);
  58
  59         return type;
  60 }
  61
  62 int af_alg_register_type(const struct af_alg_type *type)
  63 {
  64         struct alg_type_list *node;
  65         int err = -EEXIST;
  66
  67         down_write(&alg_types_sem);
  68         list_for_each_entry(node, &alg_types, list) {
  69                 if (!strcmp(node->type->name, type->name))
  70                         goto unlock;
  71         }
  72
  73         node = kmalloc(sizeof(*node), GFP_KERNEL);
  74         err = -ENOMEM;
  75         if (!node)
  76                 goto unlock;
  77
  78         type->ops->owner = THIS_MODULE;
  79         if (type->ops_nokey)
  80                 type->ops_nokey->owner = THIS_MODULE;
  81         node->type = type;
  82         list_add(&node->list, &alg_types);
  83         err = 0;
  84
  85 unlock:
  86         up_write(&alg_types_sem);
  87
  88         return err;
  89 }
  90 EXPORT_SYMBOL_GPL(af_alg_register_type);
  91
  92 int af_alg_unregister_type(const struct af_alg_type *type)
  93 {
  94         struct alg_type_list *node;
  95         int err = -ENOENT;
  96
  97         down_write(&alg_types_sem);
  98         list_for_each_entry(node, &alg_types, list) {
  99                 if (strcmp(node->type->name, type->name))
 100                         continue;
 101
 102                 list_del(&node->list);
 103                 kfree(node);
 104                 err = 0;
 105                 break;
 106         }
 107         up_write(&alg_types_sem);
 108
 109         return err;
 110 }
 111 EXPORT_SYMBOL_GPL(af_alg_unregister_type);
 112
 113 static void alg_do_release(const struct af_alg_type *type, void *private)
 114 {
 115         if (!type)
 116                 return;
 117
 118         type->release(private);
 119         module_put(type->owner);
 120 }
 121
 122 int af_alg_release(struct socket *sock)
 123 {
 124         if (sock->sk)
 125                 sock_put(sock->sk);
 126         return 0;
 127 }
 128 EXPORT_SYMBOL_GPL(af_alg_release);
 129
 130 void af_alg_release_parent(struct sock *sk)
 131 {
 132         struct alg_sock *ask = alg_sk(sk);
 133         unsigned int nokey = ask->nokey_refcnt;
 134         bool last = nokey && !ask->refcnt;
 135
 136         sk = ask->parent;
 137         ask = alg_sk(sk);
 138
 139         lock_sock(sk);
 140         ask->nokey_refcnt -= nokey;
 141         if (!last)
 142                 last = !--ask->refcnt;
 143         release_sock(sk);
 144
 145         if (last)
 146                 sock_put(sk);
 147 }
 148 EXPORT_SYMBOL_GPL(af_alg_release_parent);
 149
 150 static int alg_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 151 {
 152         struct sock *sk = sock->sk;
 153         struct alg_sock *ask = alg_sk(sk);
 154         struct sockaddr_alg *sa = (void *)uaddr;
 155         const struct af_alg_type *type;
 156         void *private;
 157         int err;
 158
 159         if (sock->state == SS_CONNECTED)
 160                 return -EINVAL;
 161
 162         if (addr_len != sizeof(*sa))
 163                 return -EINVAL;
 164
 165         sa->salg_type[sizeof(sa->salg_type) - 1] = 0;
 166         sa->salg_name[sizeof(sa->salg_name) - 1] = 0;
 167
 168         type = alg_get_type(sa->salg_type);
 169         if (IS_ERR(type) && PTR_ERR(type) == -ENOENT) {
 170                 request_module("algif-%s", sa->salg_type);
 171                 type = alg_get_type(sa->salg_type);
 172         }
 173
 174         if (IS_ERR(type))
 175                 return PTR_ERR(type);
 176
 177         private = type->bind(sa->salg_name, sa->salg_feat, sa->salg_mask);
 178         if (IS_ERR(private)) {
 179                 module_put(type->owner);
 180                 return PTR_ERR(private);
 181         }
 182
 183         err = -EBUSY;
 184         lock_sock(sk);
 185         if (ask->refcnt | ask->nokey_refcnt)
 186                 goto unlock;
 187
 188         swap(ask->type, type);
 189         swap(ask->private, private);
 190
 191         err = 0;
 192
 193 unlock:
 194         release_sock(sk);
 195
 196         alg_do_release(type, private);
 197
 198         return err;
 199 }
 200
 201 static int alg_setkey(struct sock *sk, char __user *ukey,
 202                       unsigned int keylen)
 203 {
 204         struct alg_sock *ask = alg_sk(sk);
 205         const struct af_alg_type *type = ask->type;
 206         u8 *key;
 207         int err;
 208
 209         key = sock_kmalloc(sk, keylen, GFP_KERNEL);
 210         if (!key)
 211                 return -ENOMEM;
 212
 213         err = -EFAULT;
 214         if (copy_from_user(key, ukey, keylen))
 215                 goto out;
 216
 217         err = type->setkey(ask->private, key, keylen);
 218
 219 out:
 220         sock_kzfree_s(sk, key, keylen);
 221
 222         return err;
 223 }
 224
 225 static int alg_setsockopt(struct socket *sock, int level, int optname,
 226                           char __user *optval, unsigned int optlen)
 227 {
 228         struct sock *sk = sock->sk;
 229         struct alg_sock *ask = alg_sk(sk);
 230         const struct af_alg_type *type;
 231         int err = -EBUSY;
 232
 233         lock_sock(sk);
 234         if (ask->refcnt)
 235                 goto unlock;
 236
 237         type = ask->type;
 238
 239         err = -ENOPROTOOPT;
 240         if (level != SOL_ALG || !type)
 241                 goto unlock;
 242
 243         switch (optname) {
 244         case ALG_SET_KEY:
 245                 if (sock->state == SS_CONNECTED)
 246                         goto unlock;
 247                 if (!type->setkey)
 248                         goto unlock;
 249
 250                 err = alg_setkey(sk, optval, optlen);
 251                 break;
 252         case ALG_SET_AEAD_AUTHSIZE:
 253                 if (sock->state == SS_CONNECTED)
 254                         goto unlock;
 255                 if (!type->setauthsize)
 256                         goto unlock;
 257                 err = type->setauthsize(ask->private, optlen);
 258         }
 259
 260 unlock:
 261         release_sock(sk);
 262
 263         return err;
 264 }
 265
 266 int af_alg_accept(struct sock *sk, struct socket *newsock)
 267 {
 268         struct alg_sock *ask = alg_sk(sk);
 269         const struct af_alg_type *type;
 270         struct sock *sk2;
 271         unsigned int nokey;
 272         int err;
 273
 274         lock_sock(sk);
 275         type = ask->type;
 276
 277         err = -EINVAL;
 278         if (!type)
 279                 goto unlock;
 280
 281         sk2 = sk_alloc(sock_net(sk), PF_ALG, GFP_KERNEL, &alg_proto);
 282         err = -ENOMEM;
 283         if (!sk2)
 284                 goto unlock;
 285
 286         sock_init_data(newsock, sk2);
 287         sock_graft(sk2, newsock);
 288         security_sk_clone(sk, sk2);
 289
 290         err = type->accept(ask->private, sk2);
 291
 292         nokey = err == -ENOKEY;
 293         if (nokey && type->accept_nokey)
 294                 err = type->accept_nokey(ask->private, sk2);
 295
 296         if (err)
 297                 goto unlock;
 298
 299         sk2->sk_family = PF_ALG;
 300
 301         if (nokey || !ask->refcnt++)
 302                 sock_hold(sk);
 303         ask->nokey_refcnt += nokey;
 304         alg_sk(sk2)->parent = sk;
 305         alg_sk(sk2)->type = type;
 306         alg_sk(sk2)->nokey_refcnt = nokey;
 307
 308         newsock->ops = type->ops;
 309         newsock->state = SS_CONNECTED;
 310
 311         if (nokey)
 312                 newsock->ops = type->ops_nokey;
 313
 314         err = 0;
 315
 316 unlock:
 317         release_sock(sk);
 318
 319         return err;
 320 }
 321 EXPORT_SYMBOL_GPL(af_alg_accept);
 322
 323 static int alg_accept(struct socket *sock, struct socket *newsock, int flags)
 324 {
 325         return af_alg_accept(sock->sk, newsock);
 326 }
 327
 328 static const struct proto_ops alg_proto_ops = {
 329         .family         =       PF_ALG,
 330         .owner          =       THIS_MODULE,
 331
 332         .connect        =       sock_no_connect,
 333         .socketpair     =       sock_no_socketpair,
 334         .getname        =       sock_no_getname,
 335         .ioctl          =       sock_no_ioctl,
 336         .listen         =       sock_no_listen,
 337         .shutdown       =       sock_no_shutdown,
 338         .getsockopt     =       sock_no_getsockopt,
 339         .mmap           =       sock_no_mmap,
 340         .sendpage       =       sock_no_sendpage,
 341         .sendmsg        =       sock_no_sendmsg,
 342         .recvmsg        =       sock_no_recvmsg,
 343         .poll           =       sock_no_poll,
 344
 345         .bind           =       alg_bind,
 346         .release        =       af_alg_release,
 347         .setsockopt     =       alg_setsockopt,
 348         .accept         =       alg_accept,
 349 };
 350
 351 static void alg_sock_destruct(struct sock *sk)
 352 {
 353         struct alg_sock *ask = alg_sk(sk);
 354
 355         alg_do_release(ask->type, ask->private);
 356 }
 357
 358 static int alg_create(struct net *net, struct socket *sock, int protocol,
 359                       int kern)
 360 {
 361         struct sock *sk;
 362         int err;
 363
 364         if (sock->type != SOCK_SEQPACKET)
 365                 return -ESOCKTNOSUPPORT;
 366         if (protocol != 0)
 367                 return -EPROTONOSUPPORT;
 368
 369         err = -ENOMEM;
 370         sk = sk_alloc(net, PF_ALG, GFP_KERNEL, &alg_proto);
 371         if (!sk)
 372                 goto out;
 373
 374         sock->ops = &alg_proto_ops;
 375         sock_init_data(sock, sk);
 376
 377         sk->sk_family = PF_ALG;
 378         sk->sk_destruct = alg_sock_destruct;
 379
 380         return 0;
 381 out:
 382         return err;
 383 }
 384
 385 static const struct net_proto_family alg_family = {
 386         .family =       PF_ALG,
 387         .create =       alg_create,
 388         .owner  =       THIS_MODULE,
 389 };
 390
 391 int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len)
 392 {
 393         size_t off;
 394         ssize_t n;
 395         int npages, i;
 396
 397         n = iov_iter_get_pages(iter, sgl->pages, len, ALG_MAX_PAGES, &off);
 398         if (n < 0)
 399                 return n;
 400
 401         npages = (off + n + PAGE_SIZE - 1) >> PAGE_SHIFT;
 402         if (WARN_ON(npages == 0))
 403                 return -EINVAL;
 404         /* Add one extra for linking */
 405         sg_init_table(sgl->sg, npages + 1);
 406
 407         for (i = 0, len = n; i < npages; i++) {
 408                 int plen = min_t(int, len, PAGE_SIZE - off);
 409
 410                 sg_set_page(sgl->sg + i, sgl->pages[i], plen, off);
 411
 412                 off = 0;
 413                 len -= plen;
 414         }
 415         sg_mark_end(sgl->sg + npages - 1);
 416         sgl->npages = npages;
 417
 418         return n;
 419 }
 420 EXPORT_SYMBOL_GPL(af_alg_make_sg);
 421
 422 void af_alg_link_sg(struct af_alg_sgl *sgl_prev, struct af_alg_sgl *sgl_new)
 423 {
 424         sg_unmark_end(sgl_prev->sg + sgl_prev->npages - 1);
 425         sg_chain(sgl_prev->sg, sgl_prev->npages + 1, sgl_new->sg);
 426 }
 427 EXPORT_SYMBOL_GPL(af_alg_link_sg);
 428
 429 void af_alg_free_sg(struct af_alg_sgl *sgl)
 430 {
 431         int i;
 432
 433         for (i = 0; i < sgl->npages; i++)
 434                 put_page(sgl->pages[i]);
 435 }
 436 EXPORT_SYMBOL_GPL(af_alg_free_sg);
 437
 438 int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con)
 439 {
 440         struct cmsghdr *cmsg;
 441
 442         for_each_cmsghdr(cmsg, msg) {
 443                 if (!CMSG_OK(msg, cmsg))
 444                         return -EINVAL;
 445                 if (cmsg->cmsg_level != SOL_ALG)
 446                         continue;
 447
 448                 switch (cmsg->cmsg_type) {
 449                 case ALG_SET_IV:
 450                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(*con->iv)))
 451                                 return -EINVAL;
 452                         con->iv = (void *)CMSG_DATA(cmsg);
 453                         if (cmsg->cmsg_len < CMSG_LEN(con->iv->ivlen +
 454                                                       sizeof(*con->iv)))
 455                                 return -EINVAL;
 456                         break;
 457
 458                 case ALG_SET_OP:
 459                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
 460                                 return -EINVAL;
 461                         con->op = *(u32 *)CMSG_DATA(cmsg);
 462                         break;
 463
 464                 case ALG_SET_AEAD_ASSOCLEN:
 465                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
 466                                 return -EINVAL;
 467                         con->aead_assoclen = *(u32 *)CMSG_DATA(cmsg);
 468                         break;
 469
 470                 default:
 471                         return -EINVAL;
 472                 }
 473         }
 474
 475         return 0;
 476 }
 477 EXPORT_SYMBOL_GPL(af_alg_cmsg_send);
 478
 479 int af_alg_wait_for_completion(int err, struct af_alg_completion *completion)
 480 {
 481         switch (err) {
 482         case -EINPROGRESS:
 483         case -EBUSY:
 484                 wait_for_completion(&completion->completion);
 485                 reinit_completion(&completion->completion);
 486                 err = completion->err;
 487                 break;
 488         };
 489
 490         return err;
 491 }
 492 EXPORT_SYMBOL_GPL(af_alg_wait_for_completion);
 493
 494 void af_alg_complete(struct crypto_async_request *req, int err)
 495 {
 496         struct af_alg_completion *completion = req->data;
 497
 498         if (err == -EINPROGRESS)
 499                 return;
 500
 501         completion->err = err;
 502         complete(&completion->completion);
 503 }
 504 EXPORT_SYMBOL_GPL(af_alg_complete);
 505
 506 static int __init af_alg_init(void)
 507 {
 508         int err = proto_register(&alg_proto, 0);
 509
 510         if (err)
 511                 goto out;
 512
 513         err = sock_register(&alg_family);
 514         if (err != 0)
 515                 goto out_unregister_proto;
 516
 517 out:
 518         return err;
 519
 520 out_unregister_proto:
 521         proto_unregister(&alg_proto);
 522         goto out;
 523 }
 524
 525 static void __exit af_alg_exit(void)
 526 {
 527         sock_unregister(PF_ALG);
 528         proto_unregister(&alg_proto);
 529 }
 530
 531 module_init(af_alg_init);
 532 module_exit(af_alg_exit);
 533 MODULE_LICENSE("GPL");
 534 MODULE_ALIAS_NETPROTO(AF_ALG);