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_kfree_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         }
 252
 253 unlock:
 254         release_sock(sk);
 255
 256         return err;
 257 }
 258
 259 int af_alg_accept(struct sock *sk, struct socket *newsock)
 260 {
 261         struct alg_sock *ask = alg_sk(sk);
 262         const struct af_alg_type *type;
 263         struct sock *sk2;
 264         unsigned int nokey;
 265         int err;
 266
 267         lock_sock(sk);
 268         type = ask->type;
 269
 270         err = -EINVAL;
 271         if (!type)
 272                 goto unlock;
 273
 274         sk2 = sk_alloc(sock_net(sk), PF_ALG, GFP_KERNEL, &alg_proto);
 275         err = -ENOMEM;
 276         if (!sk2)
 277                 goto unlock;
 278
 279         sock_init_data(newsock, sk2);
 280         sock_graft(sk2, newsock);
 281         security_sk_clone(sk, sk2);
 282
 283         err = type->accept(ask->private, sk2);
 284
 285         nokey = err == -ENOKEY;
 286         if (nokey && type->accept_nokey)
 287                 err = type->accept_nokey(ask->private, sk2);
 288
 289         if (err)
 290                 goto unlock;
 291
 292         sk2->sk_family = PF_ALG;
 293
 294         if (nokey || !ask->refcnt++)
 295                 sock_hold(sk);
 296         ask->nokey_refcnt += nokey;
 297         alg_sk(sk2)->parent = sk;
 298         alg_sk(sk2)->type = type;
 299         alg_sk(sk2)->nokey_refcnt = nokey;
 300
 301         newsock->ops = type->ops;
 302         newsock->state = SS_CONNECTED;
 303
 304         if (nokey)
 305                 newsock->ops = type->ops_nokey;
 306
 307         err = 0;
 308
 309 unlock:
 310         release_sock(sk);
 311
 312         return err;
 313 }
 314 EXPORT_SYMBOL_GPL(af_alg_accept);
 315
 316 static int alg_accept(struct socket *sock, struct socket *newsock, int flags)
 317 {
 318         return af_alg_accept(sock->sk, newsock);
 319 }
 320
 321 static const struct proto_ops alg_proto_ops = {
 322         .family         =       PF_ALG,
 323         .owner          =       THIS_MODULE,
 324
 325         .connect        =       sock_no_connect,
 326         .socketpair     =       sock_no_socketpair,
 327         .getname        =       sock_no_getname,
 328         .ioctl          =       sock_no_ioctl,
 329         .listen         =       sock_no_listen,
 330         .shutdown       =       sock_no_shutdown,
 331         .getsockopt     =       sock_no_getsockopt,
 332         .mmap           =       sock_no_mmap,
 333         .sendpage       =       sock_no_sendpage,
 334         .sendmsg        =       sock_no_sendmsg,
 335         .recvmsg        =       sock_no_recvmsg,
 336         .poll           =       sock_no_poll,
 337
 338         .bind           =       alg_bind,
 339         .release        =       af_alg_release,
 340         .setsockopt     =       alg_setsockopt,
 341         .accept         =       alg_accept,
 342 };
 343
 344 static void alg_sock_destruct(struct sock *sk)
 345 {
 346         struct alg_sock *ask = alg_sk(sk);
 347
 348         alg_do_release(ask->type, ask->private);
 349 }
 350
 351 static int alg_create(struct net *net, struct socket *sock, int protocol,
 352                       int kern)
 353 {
 354         struct sock *sk;
 355         int err;
 356
 357         if (sock->type != SOCK_SEQPACKET)
 358                 return -ESOCKTNOSUPPORT;
 359         if (protocol != 0)
 360                 return -EPROTONOSUPPORT;
 361
 362         err = -ENOMEM;
 363         sk = sk_alloc(net, PF_ALG, GFP_KERNEL, &alg_proto);
 364         if (!sk)
 365                 goto out;
 366
 367         sock->ops = &alg_proto_ops;
 368         sock_init_data(sock, sk);
 369
 370         sk->sk_family = PF_ALG;
 371         sk->sk_destruct = alg_sock_destruct;
 372
 373         return 0;
 374 out:
 375         return err;
 376 }
 377
 378 static const struct net_proto_family alg_family = {
 379         .family =       PF_ALG,
 380         .create =       alg_create,
 381         .owner  =       THIS_MODULE,
 382 };
 383
 384 int af_alg_make_sg(struct af_alg_sgl *sgl, void __user *addr, int len,
 385                    int write)
 386 {
 387         unsigned long from = (unsigned long)addr;
 388         unsigned long npages;
 389         unsigned off;
 390         int err;
 391         int i;
 392
 393         err = -EFAULT;
 394         if (!access_ok(write ? VERIFY_READ : VERIFY_WRITE, addr, len))
 395                 goto out;
 396
 397         off = from & ~PAGE_MASK;
 398         npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
 399         if (npages > ALG_MAX_PAGES)
 400                 npages = ALG_MAX_PAGES;
 401
 402         err = get_user_pages_fast(from, npages, write, sgl->pages);
 403         if (err < 0)
 404                 goto out;
 405
 406         npages = err;
 407         err = -EINVAL;
 408         if (WARN_ON(npages == 0))
 409                 goto out;
 410
 411         err = 0;
 412
 413         sg_init_table(sgl->sg, npages);
 414
 415         for (i = 0; i < npages; i++) {
 416                 int plen = min_t(int, len, PAGE_SIZE - off);
 417
 418                 sg_set_page(sgl->sg + i, sgl->pages[i], plen, off);
 419
 420                 off = 0;
 421                 len -= plen;
 422                 err += plen;
 423         }
 424
 425 out:
 426         return err;
 427 }
 428 EXPORT_SYMBOL_GPL(af_alg_make_sg);
 429
 430 void af_alg_free_sg(struct af_alg_sgl *sgl)
 431 {
 432         int i;
 433
 434         i = 0;
 435         do {
 436                 put_page(sgl->pages[i]);
 437         } while (!sg_is_last(sgl->sg + (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 (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
 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                 default:
 468                         return -EINVAL;
 469                 }
 470         }
 471
 472         return 0;
 473 }
 474 EXPORT_SYMBOL_GPL(af_alg_cmsg_send);
 475
 476 int af_alg_wait_for_completion(int err, struct af_alg_completion *completion)
 477 {
 478         switch (err) {
 479         case -EINPROGRESS:
 480         case -EBUSY:
 481                 wait_for_completion(&completion->completion);
 482                 INIT_COMPLETION(completion->completion);
 483                 err = completion->err;
 484                 break;
 485         };
 486
 487         return err;
 488 }
 489 EXPORT_SYMBOL_GPL(af_alg_wait_for_completion);
 490
 491 void af_alg_complete(struct crypto_async_request *req, int err)
 492 {
 493         struct af_alg_completion *completion = req->data;
 494
 495         if (err == -EINPROGRESS)
 496                 return;
 497
 498         completion->err = err;
 499         complete(&completion->completion);
 500 }
 501 EXPORT_SYMBOL_GPL(af_alg_complete);
 502
 503 static int __init af_alg_init(void)
 504 {
 505         int err = proto_register(&alg_proto, 0);
 506
 507         if (err)
 508                 goto out;
 509
 510         err = sock_register(&alg_family);
 511         if (err != 0)
 512                 goto out_unregister_proto;
 513
 514 out:
 515         return err;
 516
 517 out_unregister_proto:
 518         proto_unregister(&alg_proto);
 519         goto out;
 520 }
 521
 522 static void __exit af_alg_exit(void)
 523 {
 524         sock_unregister(PF_ALG);
 525         proto_unregister(&alg_proto);
 526 }
 527
 528 module_init(af_alg_init);
 529 module_exit(af_alg_exit);
 530 MODULE_LICENSE("GPL");
 531 MODULE_ALIAS_NETPROTO(AF_ALG);