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         bool last;
 134
 135         sk = ask->parent;
 136         ask = alg_sk(sk);
 137
 138         lock_sock(sk);
 139         last = !--ask->refcnt;
 140         release_sock(sk);
 141
 142         if (last)
 143                 sock_put(sk);
 144 }
 145 EXPORT_SYMBOL_GPL(af_alg_release_parent);
 146
 147 static int alg_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 148 {
 149         const u32 forbidden = CRYPTO_ALG_INTERNAL;
 150         struct sock *sk = sock->sk;
 151         struct alg_sock *ask = alg_sk(sk);
 152         struct sockaddr_alg *sa = (void *)uaddr;
 153         const struct af_alg_type *type;
 154         void *private;
 155         int err;
 156
 157         if (sock->state == SS_CONNECTED)
 158                 return -EINVAL;
 159
 160         if (addr_len != sizeof(*sa))
 161                 return -EINVAL;
 162
 163         sa->salg_type[sizeof(sa->salg_type) - 1] = 0;
 164         sa->salg_name[sizeof(sa->salg_name) - 1] = 0;
 165
 166         type = alg_get_type(sa->salg_type);
 167         if (IS_ERR(type) && PTR_ERR(type) == -ENOENT) {
 168                 request_module("algif-%s", sa->salg_type);
 169                 type = alg_get_type(sa->salg_type);
 170         }
 171
 172         if (IS_ERR(type))
 173                 return PTR_ERR(type);
 174
 175         private = type->bind(sa->salg_name,
 176                              sa->salg_feat & ~forbidden,
 177                              sa->salg_mask & ~forbidden);
 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)
 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         int err;
 272         bool nokey;
 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, 0);
 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         alg_sk(sk2)->parent = sk;
 304         alg_sk(sk2)->type = type;
 305
 306         newsock->ops = type->ops;
 307         newsock->state = SS_CONNECTED;
 308
 309         if (nokey)
 310                 newsock->ops = type->ops_nokey;
 311
 312         err = 0;
 313
 314 unlock:
 315         release_sock(sk);
 316
 317         return err;
 318 }
 319 EXPORT_SYMBOL_GPL(af_alg_accept);
 320
 321 static int alg_accept(struct socket *sock, struct socket *newsock, int flags)
 322 {
 323         return af_alg_accept(sock->sk, newsock);
 324 }
 325
 326 static const struct proto_ops alg_proto_ops = {
 327         .family         =       PF_ALG,
 328         .owner          =       THIS_MODULE,
 329
 330         .connect        =       sock_no_connect,
 331         .socketpair     =       sock_no_socketpair,
 332         .getname        =       sock_no_getname,
 333         .ioctl          =       sock_no_ioctl,
 334         .listen         =       sock_no_listen,
 335         .shutdown       =       sock_no_shutdown,
 336         .getsockopt     =       sock_no_getsockopt,
 337         .mmap           =       sock_no_mmap,
 338         .sendpage       =       sock_no_sendpage,
 339         .sendmsg        =       sock_no_sendmsg,
 340         .recvmsg        =       sock_no_recvmsg,
 341         .poll           =       sock_no_poll,
 342
 343         .bind           =       alg_bind,
 344         .release        =       af_alg_release,
 345         .setsockopt     =       alg_setsockopt,
 346         .accept         =       alg_accept,
 347 };
 348
 349 static void alg_sock_destruct(struct sock *sk)
 350 {
 351         struct alg_sock *ask = alg_sk(sk);
 352
 353         alg_do_release(ask->type, ask->private);
 354 }
 355
 356 static int alg_create(struct net *net, struct socket *sock, int protocol,
 357                       int kern)
 358 {
 359         struct sock *sk;
 360         int err;
 361
 362         if (sock->type != SOCK_SEQPACKET)
 363                 return -ESOCKTNOSUPPORT;
 364         if (protocol != 0)
 365                 return -EPROTONOSUPPORT;
 366
 367         err = -ENOMEM;
 368         sk = sk_alloc(net, PF_ALG, GFP_KERNEL, &alg_proto, kern);
 369         if (!sk)
 370                 goto out;
 371
 372         sock->ops = &alg_proto_ops;
 373         sock_init_data(sock, sk);
 374
 375         sk->sk_family = PF_ALG;
 376         sk->sk_destruct = alg_sock_destruct;
 377
 378         return 0;
 379 out:
 380         return err;
 381 }
 382
 383 static const struct net_proto_family alg_family = {
 384         .family =       PF_ALG,
 385         .create =       alg_create,
 386         .owner  =       THIS_MODULE,
 387 };
 388
 389 int af_alg_make_sg(struct af_alg_sgl *sgl, struct iov_iter *iter, int len)
 390 {
 391         size_t off;
 392         ssize_t n;
 393         int npages, i;
 394
 395         n = iov_iter_get_pages(iter, sgl->pages, len, ALG_MAX_PAGES, &off);
 396         if (n < 0)
 397                 return n;
 398
 399         npages = (off + n + PAGE_SIZE - 1) >> PAGE_SHIFT;
 400         if (WARN_ON(npages == 0))
 401                 return -EINVAL;
 402         /* Add one extra for linking */
 403         sg_init_table(sgl->sg, npages + 1);
 404
 405         for (i = 0, len = n; i < npages; i++) {
 406                 int plen = min_t(int, len, PAGE_SIZE - off);
 407
 408                 sg_set_page(sgl->sg + i, sgl->pages[i], plen, off);
 409
 410                 off = 0;
 411                 len -= plen;
 412         }
 413         sg_mark_end(sgl->sg + npages - 1);
 414         sgl->npages = npages;
 415
 416         return n;
 417 }
 418 EXPORT_SYMBOL_GPL(af_alg_make_sg);
 419
 420 void af_alg_link_sg(struct af_alg_sgl *sgl_prev, struct af_alg_sgl *sgl_new)
 421 {
 422         sg_unmark_end(sgl_prev->sg + sgl_prev->npages - 1);
 423         sg_chain(sgl_prev->sg, sgl_prev->npages + 1, sgl_new->sg);
 424 }
 425 EXPORT_SYMBOL_GPL(af_alg_link_sg);
 426
 427 void af_alg_free_sg(struct af_alg_sgl *sgl)
 428 {
 429         int i;
 430
 431         for (i = 0; i < sgl->npages; i++)
 432                 put_page(sgl->pages[i]);
 433 }
 434 EXPORT_SYMBOL_GPL(af_alg_free_sg);
 435
 436 int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con)
 437 {
 438         struct cmsghdr *cmsg;
 439
 440         for_each_cmsghdr(cmsg, msg) {
 441                 if (!CMSG_OK(msg, cmsg))
 442                         return -EINVAL;
 443                 if (cmsg->cmsg_level != SOL_ALG)
 444                         continue;
 445
 446                 switch (cmsg->cmsg_type) {
 447                 case ALG_SET_IV:
 448                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(*con->iv)))
 449                                 return -EINVAL;
 450                         con->iv = (void *)CMSG_DATA(cmsg);
 451                         if (cmsg->cmsg_len < CMSG_LEN(con->iv->ivlen +
 452                                                       sizeof(*con->iv)))
 453                                 return -EINVAL;
 454                         break;
 455
 456                 case ALG_SET_OP:
 457                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
 458                                 return -EINVAL;
 459                         con->op = *(u32 *)CMSG_DATA(cmsg);
 460                         break;
 461
 462                 case ALG_SET_AEAD_ASSOCLEN:
 463                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
 464                                 return -EINVAL;
 465                         con->aead_assoclen = *(u32 *)CMSG_DATA(cmsg);
 466                         break;
 467
 468                 default:
 469                         return -EINVAL;
 470                 }
 471         }
 472
 473         return 0;
 474 }
 475 EXPORT_SYMBOL_GPL(af_alg_cmsg_send);
 476
 477 int af_alg_wait_for_completion(int err, struct af_alg_completion *completion)
 478 {
 479         switch (err) {
 480         case -EINPROGRESS:
 481         case -EBUSY:
 482                 wait_for_completion(&completion->completion);
 483                 reinit_completion(&completion->completion);
 484                 err = completion->err;
 485                 break;
 486         };
 487
 488         return err;
 489 }
 490 EXPORT_SYMBOL_GPL(af_alg_wait_for_completion);
 491
 492 void af_alg_complete(struct crypto_async_request *req, int err)
 493 {
 494         struct af_alg_completion *completion = req->data;
 495
 496         if (err == -EINPROGRESS)
 497                 return;
 498
 499         completion->err = err;
 500         complete(&completion->completion);
 501 }
 502 EXPORT_SYMBOL_GPL(af_alg_complete);
 503
 504 static int __init af_alg_init(void)
 505 {
 506         int err = proto_register(&alg_proto, 0);
 507
 508         if (err)
 509                 goto out;
 510
 511         err = sock_register(&alg_family);
 512         if (err != 0)
 513                 goto out_unregister_proto;
 514
 515 out:
 516         return err;
 517
 518 out_unregister_proto:
 519         proto_unregister(&alg_proto);
 520         goto out;
 521 }
 522
 523 static void __exit af_alg_exit(void)
 524 {
 525         sock_unregister(PF_ALG);
 526         proto_unregister(&alg_proto);
 527 }
 528
 529 module_init(af_alg_init);
 530 module_exit(af_alg_exit);
 531 MODULE_LICENSE("GPL");
 532 MODULE_ALIAS_NETPROTO(AF_ALG);