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