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