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         const u32 forbidden = CRYPTO_ALG_INTERNAL;
 153         struct sock *sk = sock->sk;
 154         struct alg_sock *ask = alg_sk(sk);
 155         struct sockaddr_alg *sa = (void *)uaddr;
 156         const struct af_alg_type *type;
 157         void *private;
 158         int err;
 159
 160         if (sock->state == SS_CONNECTED)
 161                 return -EINVAL;
 162
 163         if (addr_len != sizeof(*sa))
 164                 return -EINVAL;
 165
 166         sa->salg_type[sizeof(sa->salg_type) - 1] = 0;
 167         sa->salg_name[sizeof(sa->salg_name) - 1] = 0;
 168
 169         type = alg_get_type(sa->salg_type);
 170         if (IS_ERR(type) && PTR_ERR(type) == -ENOENT) {
 171                 request_module("algif-%s", sa->salg_type);
 172                 type = alg_get_type(sa->salg_type);
 173         }
 174
 175         if (IS_ERR(type))
 176                 return PTR_ERR(type);
 177
 178         private = type->bind(sa->salg_name,
 179                              sa->salg_feat & ~forbidden,
 180                              sa->salg_mask & ~forbidden);
 181         if (IS_ERR(private)) {
 182                 module_put(type->owner);
 183                 return PTR_ERR(private);
 184         }
 185
 186         err = -EBUSY;
 187         lock_sock(sk);
 188         if (ask->refcnt | ask->nokey_refcnt)
 189                 goto unlock;
 190
 191         swap(ask->type, type);
 192         swap(ask->private, private);
 193
 194         err = 0;
 195
 196 unlock:
 197         release_sock(sk);
 198
 199         alg_do_release(type, private);
 200
 201         return err;
 202 }
 203
 204 static int alg_setkey(struct sock *sk, char __user *ukey,
 205                       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_user(key, ukey, keylen))
 218                 goto out;
 219
 220         err = type->setkey(ask->private, key, keylen);
 221
 222 out:
 223         sock_kzfree_s(sk, key, keylen);
 224
 225         return err;
 226 }
 227
 228 static int alg_setsockopt(struct socket *sock, int level, int optname,
 229                           char __user *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 (ask->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         }
 262
 263 unlock:
 264         release_sock(sk);
 265
 266         return err;
 267 }
 268
 269 int af_alg_accept(struct sock *sk, struct socket *newsock)
 270 {
 271         struct alg_sock *ask = alg_sk(sk);
 272         const struct af_alg_type *type;
 273         struct sock *sk2;
 274         unsigned int nokey;
 275         int err;
 276
 277         lock_sock(sk);
 278         type = ask->type;
 279
 280         err = -EINVAL;
 281         if (!type)
 282                 goto unlock;
 283
 284         sk2 = sk_alloc(sock_net(sk), PF_ALG, GFP_KERNEL, &alg_proto, 0);
 285         err = -ENOMEM;
 286         if (!sk2)
 287                 goto unlock;
 288
 289         sock_init_data(newsock, sk2);
 290         sock_graft(sk2, newsock);
 291         security_sk_clone(sk, sk2);
 292
 293         err = type->accept(ask->private, sk2);
 294
 295         nokey = err == -ENOKEY;
 296         if (nokey && type->accept_nokey)
 297                 err = type->accept_nokey(ask->private, sk2);
 298
 299         if (err)
 300                 goto unlock;
 301
 302         sk2->sk_family = PF_ALG;
 303
 304         if (nokey || !ask->refcnt++)
 305                 sock_hold(sk);
 306         ask->nokey_refcnt += nokey;
 307         alg_sk(sk2)->parent = sk;
 308         alg_sk(sk2)->type = type;
 309         alg_sk(sk2)->nokey_refcnt = nokey;
 310
 311         newsock->ops = type->ops;
 312         newsock->state = SS_CONNECTED;
 313
 314         if (nokey)
 315                 newsock->ops = type->ops_nokey;
 316
 317         err = 0;
 318
 319 unlock:
 320         release_sock(sk);
 321
 322         return err;
 323 }
 324 EXPORT_SYMBOL_GPL(af_alg_accept);
 325
 326 static int alg_accept(struct socket *sock, struct socket *newsock, int flags)
 327 {
 328         return af_alg_accept(sock->sk, newsock);
 329 }
 330
 331 static const struct proto_ops alg_proto_ops = {
 332         .family         =       PF_ALG,
 333         .owner          =       THIS_MODULE,
 334
 335         .connect        =       sock_no_connect,
 336         .socketpair     =       sock_no_socketpair,
 337         .getname        =       sock_no_getname,
 338         .ioctl          =       sock_no_ioctl,
 339         .listen         =       sock_no_listen,
 340         .shutdown       =       sock_no_shutdown,
 341         .getsockopt     =       sock_no_getsockopt,
 342         .mmap           =       sock_no_mmap,
 343         .sendpage       =       sock_no_sendpage,
 344         .sendmsg        =       sock_no_sendmsg,
 345         .recvmsg        =       sock_no_recvmsg,
 346         .poll           =       sock_no_poll,
 347
 348         .bind           =       alg_bind,
 349         .release        =       af_alg_release,
 350         .setsockopt     =       alg_setsockopt,
 351         .accept         =       alg_accept,
 352 };
 353
 354 static void alg_sock_destruct(struct sock *sk)
 355 {
 356         struct alg_sock *ask = alg_sk(sk);
 357
 358         alg_do_release(ask->type, ask->private);
 359 }
 360
 361 static int alg_create(struct net *net, struct socket *sock, int protocol,
 362                       int kern)
 363 {
 364         struct sock *sk;
 365         int err;
 366
 367         if (sock->type != SOCK_SEQPACKET)
 368                 return -ESOCKTNOSUPPORT;
 369         if (protocol != 0)
 370                 return -EPROTONOSUPPORT;
 371
 372         err = -ENOMEM;
 373         sk = sk_alloc(net, PF_ALG, GFP_KERNEL, &alg_proto, kern);
 374         if (!sk)
 375                 goto out;
 376
 377         sock->ops = &alg_proto_ops;
 378         sock_init_data(sock, sk);
 379
 380         sk->sk_family = PF_ALG;
 381         sk->sk_destruct = alg_sock_destruct;
 382
 383         return 0;
 384 out:
 385         return err;
 386 }
 387
 388 static const struct net_proto_family alg_family = {
 389         .family =       PF_ALG,
 390         .create =       alg_create,
 391         .owner  =       THIS_MODULE,
 392 };
 393
 394 int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len)
 395 {
 396         size_t off;
 397         ssize_t n;
 398         int npages, i;
 399
 400         n = iov_iter_get_pages(iter, sgl->pages, len, ALG_MAX_PAGES, &off);
 401         if (n < 0)
 402                 return n;
 403
 404         npages = (off + n + PAGE_SIZE - 1) >> PAGE_SHIFT;
 405         if (WARN_ON(npages == 0))
 406                 return -EINVAL;
 407         /* Add one extra for linking */
 408         sg_init_table(sgl->sg, npages + 1);
 409
 410         for (i = 0, len = n; i < npages; i++) {
 411                 int plen = min_t(int, len, PAGE_SIZE - off);
 412
 413                 sg_set_page(sgl->sg + i, sgl->pages[i], plen, off);
 414
 415                 off = 0;
 416                 len -= plen;
 417         }
 418         sg_mark_end(sgl->sg + npages - 1);
 419         sgl->npages = npages;
 420
 421         return n;
 422 }
 423 EXPORT_SYMBOL_GPL(af_alg_make_sg);
 424
 425 void af_alg_link_sg(struct af_alg_sgl *sgl_prev, struct af_alg_sgl *sgl_new)
 426 {
 427         sg_unmark_end(sgl_prev->sg + sgl_prev->npages - 1);
 428         sg_chain(sgl_prev->sg, sgl_prev->npages + 1, sgl_new->sg);
 429 }
 430 EXPORT_SYMBOL_GPL(af_alg_link_sg);
 431
 432 void af_alg_free_sg(struct af_alg_sgl *sgl)
 433 {
 434         int i;
 435
 436         for (i = 0; i < sgl->npages; i++)
 437                 put_page(sgl->pages[i]);
 438 }
 439 EXPORT_SYMBOL_GPL(af_alg_free_sg);
 440
 441 int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con)
 442 {
 443         struct cmsghdr *cmsg;
 444
 445         for_each_cmsghdr(cmsg, msg) {
 446                 if (!CMSG_OK(msg, cmsg))
 447                         return -EINVAL;
 448                 if (cmsg->cmsg_level != SOL_ALG)
 449                         continue;
 450
 451                 switch (cmsg->cmsg_type) {
 452                 case ALG_SET_IV:
 453                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(*con->iv)))
 454                                 return -EINVAL;
 455                         con->iv = (void *)CMSG_DATA(cmsg);
 456                         if (cmsg->cmsg_len < CMSG_LEN(con->iv->ivlen +
 457                                                       sizeof(*con->iv)))
 458                                 return -EINVAL;
 459                         break;
 460
 461                 case ALG_SET_OP:
 462                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
 463                                 return -EINVAL;
 464                         con->op = *(u32 *)CMSG_DATA(cmsg);
 465                         break;
 466
 467                 case ALG_SET_AEAD_ASSOCLEN:
 468                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
 469                                 return -EINVAL;
 470                         con->aead_assoclen = *(u32 *)CMSG_DATA(cmsg);
 471                         break;
 472
 473                 default:
 474                         return -EINVAL;
 475                 }
 476         }
 477
 478         return 0;
 479 }
 480 EXPORT_SYMBOL_GPL(af_alg_cmsg_send);
 481
 482 int af_alg_wait_for_completion(int err, struct af_alg_completion *completion)
 483 {
 484         switch (err) {
 485         case -EINPROGRESS:
 486         case -EBUSY:
 487                 wait_for_completion(&completion->completion);
 488                 reinit_completion(&completion->completion);
 489                 err = completion->err;
 490                 break;
 491         };
 492
 493         return err;
 494 }
 495 EXPORT_SYMBOL_GPL(af_alg_wait_for_completion);
 496
 497 void af_alg_complete(struct crypto_async_request *req, int err)
 498 {
 499         struct af_alg_completion *completion = req->data;
 500
 501         if (err == -EINPROGRESS)
 502                 return;
 503
 504         completion->err = err;
 505         complete(&completion->completion);
 506 }
 507 EXPORT_SYMBOL_GPL(af_alg_complete);
 508
 509 static int __init af_alg_init(void)
 510 {
 511         int err = proto_register(&alg_proto, 0);
 512
 513         if (err)
 514                 goto out;
 515
 516         err = sock_register(&alg_family);
 517         if (err != 0)
 518                 goto out_unregister_proto;
 519
 520 out:
 521         return err;
 522
 523 out_unregister_proto:
 524         proto_unregister(&alg_proto);
 525         goto out;
 526 }
 527
 528 static void __exit af_alg_exit(void)
 529 {
 530         sock_unregister(PF_ALG);
 531         proto_unregister(&alg_proto);
 532 }
 533
 534 module_init(af_alg_init);
 535 module_exit(af_alg_exit);
 536 MODULE_LICENSE("GPL");
 537 MODULE_ALIAS_NETPROTO(AF_ALG);