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 <asm/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
  25 struct alg_type_list {
  26         const struct af_alg_type *type;
  27         struct list_head list;
  28 };
  29
  30 static atomic_long_t alg_memory_allocated;
  31
  32 static struct proto alg_proto = {
  33         .name                   = "ALG",
  34         .owner                  = THIS_MODULE,
  35         .memory_allocated       = &alg_memory_allocated,
  36         .obj_size               = sizeof(struct alg_sock),
  37 };
  38
  39 static LIST_HEAD(alg_types);
  40 static DECLARE_RWSEM(alg_types_sem);
  41
  42 static const struct af_alg_type *alg_get_type(const char *name)
  43 {
  44         const struct af_alg_type *type = ERR_PTR(-ENOENT);
  45         struct alg_type_list *node;
  46
  47         down_read(&alg_types_sem);
  48         list_for_each_entry(node, &alg_types, list) {
  49                 if (strcmp(node->type->name, name))
  50                         continue;
  51
  52                 if (try_module_get(node->type->owner))
  53                         type = node->type;
  54                 break;
  55         }
  56         up_read(&alg_types_sem);
  57
  58         return type;
  59 }
  60
  61 int af_alg_register_type(const struct af_alg_type *type)
  62 {
  63         struct alg_type_list *node;
  64         int err = -EEXIST;
  65
  66         down_write(&alg_types_sem);
  67         list_for_each_entry(node, &alg_types, list) {
  68                 if (!strcmp(node->type->name, type->name))
  69                         goto unlock;
  70         }
  71
  72         node = kmalloc(sizeof(*node), GFP_KERNEL);
  73         err = -ENOMEM;
  74         if (!node)
  75                 goto unlock;
  76
  77         type->ops->owner = THIS_MODULE;
  78         node->type = type;
  79         list_add(&node->list, &alg_types);
  80         err = 0;
  81
  82 unlock:
  83         up_write(&alg_types_sem);
  84
  85         return err;
  86 }
  87 EXPORT_SYMBOL_GPL(af_alg_register_type);
  88
  89 int af_alg_unregister_type(const struct af_alg_type *type)
  90 {
  91         struct alg_type_list *node;
  92         int err = -ENOENT;
  93
  94         down_write(&alg_types_sem);
  95         list_for_each_entry(node, &alg_types, list) {
  96                 if (strcmp(node->type->name, type->name))
  97                         continue;
  98
  99                 list_del(&node->list);
 100                 kfree(node);
 101                 err = 0;
 102                 break;
 103         }
 104         up_write(&alg_types_sem);
 105
 106         return err;
 107 }
 108 EXPORT_SYMBOL_GPL(af_alg_unregister_type);
 109
 110 static void alg_do_release(const struct af_alg_type *type, void *private)
 111 {
 112         if (!type)
 113                 return;
 114
 115         type->release(private);
 116         module_put(type->owner);
 117 }
 118
 119 int af_alg_release(struct socket *sock)
 120 {
 121         if (sock->sk)
 122                 sock_put(sock->sk);
 123         return 0;
 124 }
 125 EXPORT_SYMBOL_GPL(af_alg_release);
 126
 127 static int alg_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
 128 {
 129         struct sock *sk = sock->sk;
 130         struct alg_sock *ask = alg_sk(sk);
 131         struct sockaddr_alg *sa = (void *)uaddr;
 132         const struct af_alg_type *type;
 133         void *private;
 134
 135         if (sock->state == SS_CONNECTED)
 136                 return -EINVAL;
 137
 138         if (addr_len != sizeof(*sa))
 139                 return -EINVAL;
 140
 141         sa->salg_type[sizeof(sa->salg_type) - 1] = 0;
 142         sa->salg_name[sizeof(sa->salg_name) - 1] = 0;
 143
 144         type = alg_get_type(sa->salg_type);
 145         if (IS_ERR(type) && PTR_ERR(type) == -ENOENT) {
 146                 request_module("algif-%s", sa->salg_type);
 147                 type = alg_get_type(sa->salg_type);
 148         }
 149
 150         if (IS_ERR(type))
 151                 return PTR_ERR(type);
 152
 153         private = type->bind(sa->salg_name, sa->salg_feat, sa->salg_mask);
 154         if (IS_ERR(private)) {
 155                 module_put(type->owner);
 156                 return PTR_ERR(private);
 157         }
 158
 159         lock_sock(sk);
 160
 161         swap(ask->type, type);
 162         swap(ask->private, private);
 163
 164         release_sock(sk);
 165
 166         alg_do_release(type, private);
 167
 168         return 0;
 169 }
 170
 171 static int alg_setkey(struct sock *sk, char __user *ukey,
 172                       unsigned int keylen)
 173 {
 174         struct alg_sock *ask = alg_sk(sk);
 175         const struct af_alg_type *type = ask->type;
 176         u8 *key;
 177         int err;
 178
 179         key = sock_kmalloc(sk, keylen, GFP_KERNEL);
 180         if (!key)
 181                 return -ENOMEM;
 182
 183         err = -EFAULT;
 184         if (copy_from_user(key, ukey, keylen))
 185                 goto out;
 186
 187         err = type->setkey(ask->private, key, keylen);
 188
 189 out:
 190         sock_kfree_s(sk, key, keylen);
 191
 192         return err;
 193 }
 194
 195 static int alg_setsockopt(struct socket *sock, int level, int optname,
 196                           char __user *optval, unsigned int optlen)
 197 {
 198         struct sock *sk = sock->sk;
 199         struct alg_sock *ask = alg_sk(sk);
 200         const struct af_alg_type *type;
 201         int err = -ENOPROTOOPT;
 202
 203         lock_sock(sk);
 204         type = ask->type;
 205
 206         if (level != SOL_ALG || !type)
 207                 goto unlock;
 208
 209         switch (optname) {
 210         case ALG_SET_KEY:
 211                 if (sock->state == SS_CONNECTED)
 212                         goto unlock;
 213                 if (!type->setkey)
 214                         goto unlock;
 215
 216                 err = alg_setkey(sk, optval, optlen);
 217         }
 218
 219 unlock:
 220         release_sock(sk);
 221
 222         return err;
 223 }
 224
 225 int af_alg_accept(struct sock *sk, struct socket *newsock)
 226 {
 227         struct alg_sock *ask = alg_sk(sk);
 228         const struct af_alg_type *type;
 229         struct sock *sk2;
 230         int err;
 231
 232         lock_sock(sk);
 233         type = ask->type;
 234
 235         err = -EINVAL;
 236         if (!type)
 237                 goto unlock;
 238
 239         sk2 = sk_alloc(sock_net(sk), PF_ALG, GFP_KERNEL, &alg_proto);
 240         err = -ENOMEM;
 241         if (!sk2)
 242                 goto unlock;
 243
 244         sock_init_data(newsock, sk2);
 245         sock_graft(sk2, newsock);
 246
 247         err = type->accept(ask->private, sk2);
 248         if (err) {
 249                 sk_free(sk2);
 250                 goto unlock;
 251         }
 252
 253         sk2->sk_family = PF_ALG;
 254
 255         sock_hold(sk);
 256         alg_sk(sk2)->parent = sk;
 257         alg_sk(sk2)->type = type;
 258
 259         newsock->ops = type->ops;
 260         newsock->state = SS_CONNECTED;
 261
 262         err = 0;
 263
 264 unlock:
 265         release_sock(sk);
 266
 267         return err;
 268 }
 269 EXPORT_SYMBOL_GPL(af_alg_accept);
 270
 271 static int alg_accept(struct socket *sock, struct socket *newsock, int flags)
 272 {
 273         return af_alg_accept(sock->sk, newsock);
 274 }
 275
 276 static const struct proto_ops alg_proto_ops = {
 277         .family         =       PF_ALG,
 278         .owner          =       THIS_MODULE,
 279
 280         .connect        =       sock_no_connect,
 281         .socketpair     =       sock_no_socketpair,
 282         .getname        =       sock_no_getname,
 283         .ioctl          =       sock_no_ioctl,
 284         .listen         =       sock_no_listen,
 285         .shutdown       =       sock_no_shutdown,
 286         .getsockopt     =       sock_no_getsockopt,
 287         .mmap           =       sock_no_mmap,
 288         .sendpage       =       sock_no_sendpage,
 289         .sendmsg        =       sock_no_sendmsg,
 290         .recvmsg        =       sock_no_recvmsg,
 291         .poll           =       sock_no_poll,
 292
 293         .bind           =       alg_bind,
 294         .release        =       af_alg_release,
 295         .setsockopt     =       alg_setsockopt,
 296         .accept         =       alg_accept,
 297 };
 298
 299 static void alg_sock_destruct(struct sock *sk)
 300 {
 301         struct alg_sock *ask = alg_sk(sk);
 302
 303         alg_do_release(ask->type, ask->private);
 304 }
 305
 306 static int alg_create(struct net *net, struct socket *sock, int protocol,
 307                       int kern)
 308 {
 309         struct sock *sk;
 310         int err;
 311
 312         if (sock->type != SOCK_SEQPACKET)
 313                 return -ESOCKTNOSUPPORT;
 314         if (protocol != 0)
 315                 return -EPROTONOSUPPORT;
 316
 317         err = -ENOMEM;
 318         sk = sk_alloc(net, PF_ALG, GFP_KERNEL, &alg_proto);
 319         if (!sk)
 320                 goto out;
 321
 322         sock->ops = &alg_proto_ops;
 323         sock_init_data(sock, sk);
 324
 325         sk->sk_family = PF_ALG;
 326         sk->sk_destruct = alg_sock_destruct;
 327
 328         return 0;
 329 out:
 330         return err;
 331 }
 332
 333 static const struct net_proto_family alg_family = {
 334         .family =       PF_ALG,
 335         .create =       alg_create,
 336         .owner  =       THIS_MODULE,
 337 };
 338
 339 int af_alg_make_sg(struct af_alg_sgl *sgl, void __user *addr, int len,
 340                    int write)
 341 {
 342         unsigned long from = (unsigned long)addr;
 343         unsigned long npages;
 344         unsigned off;
 345         int err;
 346         int i;
 347
 348         err = -EFAULT;
 349         if (!access_ok(write ? VERIFY_READ : VERIFY_WRITE, addr, len))
 350                 goto out;
 351
 352         off = from & ~PAGE_MASK;
 353         npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
 354         if (npages > ALG_MAX_PAGES)
 355                 npages = ALG_MAX_PAGES;
 356
 357         err = get_user_pages_fast(from, npages, write, sgl->pages);
 358         if (err < 0)
 359                 goto out;
 360
 361         npages = err;
 362         err = -EINVAL;
 363         if (WARN_ON(npages == 0))
 364                 goto out;
 365
 366         err = 0;
 367
 368         sg_init_table(sgl->sg, npages);
 369
 370         for (i = 0; i < npages; i++) {
 371                 int plen = min_t(int, len, PAGE_SIZE - off);
 372
 373                 sg_set_page(sgl->sg + i, sgl->pages[i], plen, off);
 374
 375                 off = 0;
 376                 len -= plen;
 377                 err += plen;
 378         }
 379
 380 out:
 381         return err;
 382 }
 383 EXPORT_SYMBOL_GPL(af_alg_make_sg);
 384
 385 void af_alg_free_sg(struct af_alg_sgl *sgl)
 386 {
 387         int i;
 388
 389         i = 0;
 390         do {
 391                 put_page(sgl->pages[i]);
 392         } while (!sg_is_last(sgl->sg + (i++)));
 393 }
 394 EXPORT_SYMBOL_GPL(af_alg_free_sg);
 395
 396 int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con)
 397 {
 398         struct cmsghdr *cmsg;
 399
 400         for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
 401                 if (!CMSG_OK(msg, cmsg))
 402                         return -EINVAL;
 403                 if (cmsg->cmsg_level != SOL_ALG)
 404                         continue;
 405
 406                 switch(cmsg->cmsg_type) {
 407                 case ALG_SET_IV:
 408                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(*con->iv)))
 409                                 return -EINVAL;
 410                         con->iv = (void *)CMSG_DATA(cmsg);
 411                         if (cmsg->cmsg_len < CMSG_LEN(con->iv->ivlen +
 412                                                       sizeof(*con->iv)))
 413                                 return -EINVAL;
 414                         break;
 415
 416                 case ALG_SET_OP:
 417                         if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32)))
 418                                 return -EINVAL;
 419                         con->op = *(u32 *)CMSG_DATA(cmsg);
 420                         break;
 421
 422                 default:
 423                         return -EINVAL;
 424                 }
 425         }
 426
 427         return 0;
 428 }
 429 EXPORT_SYMBOL_GPL(af_alg_cmsg_send);
 430
 431 int af_alg_wait_for_completion(int err, struct af_alg_completion *completion)
 432 {
 433         switch (err) {
 434         case -EINPROGRESS:
 435         case -EBUSY:
 436                 wait_for_completion(&completion->completion);
 437                 INIT_COMPLETION(completion->completion);
 438                 err = completion->err;
 439                 break;
 440         };
 441
 442         return err;
 443 }
 444 EXPORT_SYMBOL_GPL(af_alg_wait_for_completion);
 445
 446 void af_alg_complete(struct crypto_async_request *req, int err)
 447 {
 448         struct af_alg_completion *completion = req->data;
 449
 450         completion->err = err;
 451         complete(&completion->completion);
 452 }
 453 EXPORT_SYMBOL_GPL(af_alg_complete);
 454
 455 static int __init af_alg_init(void)
 456 {
 457         int err = proto_register(&alg_proto, 0);
 458
 459         if (err)
 460                 goto out;
 461
 462         err = sock_register(&alg_family);
 463         if (err != 0)
 464                 goto out_unregister_proto;
 465
 466 out:
 467         return err;
 468
 469 out_unregister_proto:
 470         proto_unregister(&alg_proto);
 471         goto out;
 472 }
 473
 474 static void __exit af_alg_exit(void)
 475 {
 476         sock_unregister(PF_ALG);
 477         proto_unregister(&alg_proto);
 478 }
 479
 480 module_init(af_alg_init);
 481 module_exit(af_alg_exit);
 482 MODULE_LICENSE("GPL");
 483 MODULE_ALIAS_NETPROTO(AF_ALG);