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 allowed = CRYPTO_ALG_KERN_DRIVER_ONLY;
 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 caller uses non-allowed flag, return error. */
 161         if ((sa->salg_feat & ~allowed) || (sa->salg_mask & ~allowed))
 162                 return -EINVAL;
 163
 164         if (sock->state == SS_CONNECTED)
 165                 return -EINVAL;
 166
 167         if (addr_len != sizeof(*sa))
 168                 return -EINVAL;
 169
 170         sa->salg_type[sizeof(sa->salg_type) - 1] = 0;
 171         sa->salg_name[sizeof(sa->salg_name) - 1] = 0;
 172
 173         type = alg_get_type(sa->salg_type);
 174         if (IS_ERR(type) && PTR_ERR(type) == -ENOENT) {
 175                 request_module("algif-%s", sa->salg_type);
 176                 type = alg_get_type(sa->salg_type);
 177         }
 178
 179         if (IS_ERR(type))
 180                 return PTR_ERR(type);
 181
 182         private = type->bind(sa->salg_name, sa->salg_feat, sa->salg_mask);
 183         if (IS_ERR(private)) {
 184                 module_put(type->owner);
 185                 return PTR_ERR(private);
 186         }
 187
 188         err = -EBUSY;
 189         lock_sock(sk);
 190         if (ask->refcnt | ask->nokey_refcnt)
 191                 goto unlock;
 192
 193         swap(ask->type, type);
 194         swap(ask->private, private);
 195
 196         err = 0;
 197
 198 unlock:
 199         release_sock(sk);
 200
 201         alg_do_release(type, private);
 202
 203         return err;
 204 }
 205
 206 static int alg_setkey(struct sock *sk, char __user *ukey,
 207                       unsigned int keylen)
 208 {
 209         struct alg_sock *ask = alg_sk(sk);
 210         const struct af_alg_type *type = ask->type;
 211         u8 *key;
 212         int err;
 213
 214         key = sock_kmalloc(sk, keylen, GFP_KERNEL);
 215         if (!key)
 216                 return -ENOMEM;
 217
 218         err = -EFAULT;
 219         if (copy_from_user(key, ukey, keylen))
 220                 goto out;
 221
 222         err = type->setkey(ask->private, key, keylen);
 223
 224 out:
 225         sock_kzfree_s(sk, key, keylen);
 226
 227         return err;
 228 }
 229
 230 static int alg_setsockopt(struct socket *sock, int level, int optname,
 231                           char __user *optval, unsigned int optlen)
 232 {
 233         struct sock *sk = sock->sk;
 234         struct alg_sock *ask = alg_sk(sk);
 235         const struct af_alg_type *type;
 236         int err = -EBUSY;
 237
 238         lock_sock(sk);
 239         if (ask->refcnt)
 240                 goto unlock;
 241
 242         type = ask->type;
 243
 244         err = -ENOPROTOOPT;
 245         if (level != SOL_ALG || !type)
 246                 goto unlock;
 247
 248         switch (optname) {
 249         case ALG_SET_KEY:
 250                 if (sock->state == SS_CONNECTED)
 251                         goto unlock;
 252                 if (!type->setkey)
 253                         goto unlock;
 254
 255                 err = alg_setkey(sk, optval, optlen);
 256                 break;
 257         case ALG_SET_AEAD_AUTHSIZE:
 258                 if (sock->state == SS_CONNECTED)
 259                         goto unlock;
 260                 if (!type->setauthsize)
 261                         goto unlock;
 262                 err = type->setauthsize(ask->private, optlen);
 263         }
 264
 265 unlock:
 266         release_sock(sk);
 267
 268         return err;
 269 }
 270
 271 int af_alg_accept(struct sock *sk, struct socket *newsock)
 272 {
 273         struct alg_sock *ask = alg_sk(sk);
 274         const struct af_alg_type *type;
 275         struct sock *sk2;
 276         unsigned int nokey;
 277         int err;
 278
 279         lock_sock(sk);
 280         type = ask->type;
 281
 282         err = -EINVAL;
 283         if (!type)
 284                 goto unlock;
 285
 286         sk2 = sk_alloc(sock_net(sk), PF_ALG, GFP_KERNEL, &alg_proto, 0);
 287         err = -ENOMEM;
 288         if (!sk2)
 289                 goto unlock;
 290
 291         sock_init_data(newsock, sk2);
 292         sock_graft(sk2, newsock);
 293         security_sk_clone(sk, sk2);
 294
 295         err = type->accept(ask->private, sk2);
 296
 297         nokey = err == -ENOKEY;
 298         if (nokey && type->accept_nokey)
 299                 err = type->accept_nokey(ask->private, sk2);
 300
 301         if (err)
 302                 goto unlock;
 303
 304         sk2->sk_family = PF_ALG;
 305
 306         if (nokey || !ask->refcnt++)
 307                 sock_hold(sk);
 308         ask->nokey_refcnt += nokey;
 309         alg_sk(sk2)->parent = sk;
 310         alg_sk(sk2)->type = type;
 311         alg_sk(sk2)->nokey_refcnt = nokey;
 312
 313         newsock->ops = type->ops;
 314         newsock->state = SS_CONNECTED;
 315
 316         if (nokey)
 317                 newsock->ops = type->ops_nokey;
 318
 319         err = 0;
 320
 321 unlock:
 322         release_sock(sk);
 323
 324         return err;
 325 }
 326 EXPORT_SYMBOL_GPL(af_alg_accept);
 327
 328 static int alg_accept(struct socket *sock, struct socket *newsock, int flags)
 329 {
 330         return af_alg_accept(sock->sk, newsock);
 331 }
 332
 333 static const struct proto_ops alg_proto_ops = {
 334         .family         =       PF_ALG,
 335         .owner          =       THIS_MODULE,
 336
 337         .connect        =       sock_no_connect,
 338         .socketpair     =       sock_no_socketpair,
 339         .getname        =       sock_no_getname,
 340         .ioctl          =       sock_no_ioctl,
 341         .listen         =       sock_no_listen,
 342         .shutdown       =       sock_no_shutdown,
 343         .getsockopt     =       sock_no_getsockopt,
 344         .mmap           =       sock_no_mmap,
 345         .sendpage       =       sock_no_sendpage,
 346         .sendmsg        =       sock_no_sendmsg,
 347         .recvmsg        =       sock_no_recvmsg,
 348         .poll           =       sock_no_poll,
 349
 350         .bind           =       alg_bind,
 351         .release        =       af_alg_release,
 352         .setsockopt     =       alg_setsockopt,
 353         .accept         =       alg_accept,
 354 };
 355
 356 static void alg_sock_destruct(struct sock *sk)
 357 {
 358         struct alg_sock *ask = alg_sk(sk);
 359
 360         alg_do_release(ask->type, ask->private);
 361 }
 362
 363 static int alg_create(struct net *net, struct socket *sock, int protocol,
 364                       int kern)
 365 {
 366         struct sock *sk;
 367         int err;
 368
 369         if (sock->type != SOCK_SEQPACKET)
 370                 return -ESOCKTNOSUPPORT;
 371         if (protocol != 0)
 372                 return -EPROTONOSUPPORT;
 373
 374         err = -ENOMEM;
 375         sk = sk_alloc(net, PF_ALG, GFP_KERNEL, &alg_proto, kern);
 376         if (!sk)
 377                 goto out;
 378
 379         sock->ops = &alg_proto_ops;
 380         sock_init_data(sock, sk);
 381
 382         sk->sk_family = PF_ALG;
 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 void af_alg_link_sg(struct af_alg_sgl *sgl_prev, struct af_alg_sgl *sgl_new)
 428 {
 429         sg_unmark_end(sgl_prev->sg + sgl_prev->npages - 1);
 430         sg_chain(sgl_prev->sg, sgl_prev->npages + 1, sgl_new->sg);
 431 }
 432 EXPORT_SYMBOL_GPL(af_alg_link_sg);
 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 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 EXPORT_SYMBOL_GPL(af_alg_cmsg_send);
 483
 484 int af_alg_wait_for_completion(int err, struct af_alg_completion *completion)
 485 {
 486         switch (err) {
 487         case -EINPROGRESS:
 488         case -EBUSY:
 489                 wait_for_completion(&completion->completion);
 490                 reinit_completion(&completion->completion);
 491                 err = completion->err;
 492                 break;
 493         };
 494
 495         return err;
 496 }
 497 EXPORT_SYMBOL_GPL(af_alg_wait_for_completion);
 498
 499 void af_alg_complete(struct crypto_async_request *req, int err)
 500 {
 501         struct af_alg_completion *completion = req->data;
 502
 503         if (err == -EINPROGRESS)
 504                 return;
 505
 506         completion->err = err;
 507         complete(&completion->completion);
 508 }
 509 EXPORT_SYMBOL_GPL(af_alg_complete);
 510
 511 static int __init af_alg_init(void)
 512 {
 513         int err = proto_register(&alg_proto, 0);
 514
 515         if (err)
 516                 goto out;
 517
 518         err = sock_register(&alg_family);
 519         if (err != 0)
 520                 goto out_unregister_proto;
 521
 522 out:
 523         return err;
 524
 525 out_unregister_proto:
 526         proto_unregister(&alg_proto);
 527         goto out;
 528 }
 529
 530 static void __exit af_alg_exit(void)
 531 {
 532         sock_unregister(PF_ALG);
 533         proto_unregister(&alg_proto);
 534 }
 535
 536 module_init(af_alg_init);
 537 module_exit(af_alg_exit);
 538 MODULE_LICENSE("GPL");
 539 MODULE_ALIAS_NETPROTO(AF_ALG);