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_kfree_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         }
 219
 220 unlock:
 221         release_sock(sk);
 222
 223         return err;
 224 }
 225
 226 int af_alg_accept(struct sock *sk, struct socket *newsock)
 227 {
 228         struct alg_sock *ask = alg_sk(sk);
 229         const struct af_alg_type *type;
 230         struct sock *sk2;
 231         int err;
 232
 233         lock_sock(sk);
 234         type = ask->type;
 235
 236         err = -EINVAL;
 237         if (!type)
 238                 goto unlock;
 239
 240         sk2 = sk_alloc(sock_net(sk), PF_ALG, GFP_KERNEL, &alg_proto);
 241         err = -ENOMEM;
 242         if (!sk2)
 243                 goto unlock;
 244
 245         sock_init_data(newsock, sk2);
 246         sock_graft(sk2, newsock);
 247         security_sk_clone(sk, sk2);
 248
 249         err = type->accept(ask->private, sk2);
 250         if (err) {
 251                 sk_free(sk2);
 252                 goto unlock;
 253         }
 254
 255         sk2->sk_family = PF_ALG;
 256
 257         sock_hold(sk);
 258         alg_sk(sk2)->parent = sk;
 259         alg_sk(sk2)->type = type;
 260
 261         newsock->ops = type->ops;
 262         newsock->state = SS_CONNECTED;
 263
 264         err = 0;
 265
 266 unlock:
 267         release_sock(sk);
 268
 269         return err;
 270 }
 271 EXPORT_SYMBOL_GPL(af_alg_accept);
 272
 273 static int alg_accept(struct socket *sock, struct socket *newsock, int flags)
 274 {
 275         return af_alg_accept(sock->sk, newsock);
 276 }
 277
 278 static const struct proto_ops alg_proto_ops = {
 279         .family         =       PF_ALG,
 280         .owner          =       THIS_MODULE,
 281
 282         .connect        =       sock_no_connect,
 283         .socketpair     =       sock_no_socketpair,
 284         .getname        =       sock_no_getname,
 285         .ioctl          =       sock_no_ioctl,
 286         .listen         =       sock_no_listen,
 287         .shutdown       =       sock_no_shutdown,
 288         .getsockopt     =       sock_no_getsockopt,
 289         .mmap           =       sock_no_mmap,
 290         .sendpage       =       sock_no_sendpage,
 291         .sendmsg        =       sock_no_sendmsg,
 292         .recvmsg        =       sock_no_recvmsg,
 293         .poll           =       sock_no_poll,
 294
 295         .bind           =       alg_bind,
 296         .release        =       af_alg_release,
 297         .setsockopt     =       alg_setsockopt,
 298         .accept         =       alg_accept,
 299 };
 300
 301 static void alg_sock_destruct(struct sock *sk)
 302 {
 303         struct alg_sock *ask = alg_sk(sk);
 304
 305         alg_do_release(ask->type, ask->private);
 306 }
 307
 308 static int alg_create(struct net *net, struct socket *sock, int protocol,
 309                       int kern)
 310 {
 311         struct sock *sk;
 312         int err;
 313
 314         if (sock->type != SOCK_SEQPACKET)
 315                 return -ESOCKTNOSUPPORT;
 316         if (protocol != 0)
 317                 return -EPROTONOSUPPORT;
 318
 319         err = -ENOMEM;
 320         sk = sk_alloc(net, PF_ALG, GFP_KERNEL, &alg_proto);
 321         if (!sk)
 322                 goto out;
 323
 324         sock->ops = &alg_proto_ops;
 325         sock_init_data(sock, sk);
 326
 327         sk->sk_family = PF_ALG;
 328         sk->sk_destruct = alg_sock_destruct;
 329
 330         return 0;
 331 out:
 332         return err;
 333 }
 334
 335 static const struct net_proto_family alg_family = {
 336         .family =       PF_ALG,
 337         .create =       alg_create,
 338         .owner  =       THIS_MODULE,
 339 };
 340
 341 int af_alg_make_sg(struct af_alg_sgl *sgl, void __user *addr, int len,
 342                    int write)
 343 {
 344         unsigned long from = (unsigned long)addr;
 345         unsigned long npages;
 346         unsigned off;
 347         int err;
 348         int i;
 349
 350         err = -EFAULT;
 351         if (!access_ok(write ? VERIFY_READ : VERIFY_WRITE, addr, len))
 352                 goto out;
 353
 354         off = from & ~PAGE_MASK;
 355         npages = (off + len + PAGE_SIZE - 1) >> PAGE_SHIFT;
 356         if (npages > ALG_MAX_PAGES)
 357                 npages = ALG_MAX_PAGES;
 358
 359         err = get_user_pages_fast(from, npages, write, sgl->pages);
 360         if (err < 0)
 361                 goto out;
 362
 363         npages = err;
 364         err = -EINVAL;
 365         if (WARN_ON(npages == 0))
 366                 goto out;
 367
 368         err = 0;
 369
 370         sg_init_table(sgl->sg, npages);
 371
 372         for (i = 0; i < npages; i++) {
 373                 int plen = min_t(int, len, PAGE_SIZE - off);
 374
 375                 sg_set_page(sgl->sg + i, sgl->pages[i], plen, off);
 376
 377                 off = 0;
 378                 len -= plen;
 379                 err += plen;
 380         }
 381
 382 out:
 383         return err;
 384 }
 385 EXPORT_SYMBOL_GPL(af_alg_make_sg);
 386
 387 void af_alg_free_sg(struct af_alg_sgl *sgl)
 388 {
 389         int i;
 390
 391         i = 0;
 392         do {
 393                 put_page(sgl->pages[i]);
 394         } while (!sg_is_last(sgl->sg + (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 (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
 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                 default:
 425                         return -EINVAL;
 426                 }
 427         }
 428
 429         return 0;
 430 }
 431 EXPORT_SYMBOL_GPL(af_alg_cmsg_send);
 432
 433 int af_alg_wait_for_completion(int err, struct af_alg_completion *completion)
 434 {
 435         switch (err) {
 436         case -EINPROGRESS:
 437         case -EBUSY:
 438                 wait_for_completion(&completion->completion);
 439                 INIT_COMPLETION(completion->completion);
 440                 err = completion->err;
 441                 break;
 442         };
 443
 444         return err;
 445 }
 446 EXPORT_SYMBOL_GPL(af_alg_wait_for_completion);
 447
 448 void af_alg_complete(struct crypto_async_request *req, int err)
 449 {
 450         struct af_alg_completion *completion = req->data;
 451
 452         completion->err = err;
 453         complete(&completion->completion);
 454 }
 455 EXPORT_SYMBOL_GPL(af_alg_complete);
 456
 457 static int __init af_alg_init(void)
 458 {
 459         int err = proto_register(&alg_proto, 0);
 460
 461         if (err)
 462                 goto out;
 463
 464         err = sock_register(&alg_family);
 465         if (err != 0)
 466                 goto out_unregister_proto;
 467
 468 out:
 469         return err;
 470
 471 out_unregister_proto:
 472         proto_unregister(&alg_proto);
 473         goto out;
 474 }
 475
 476 static void __exit af_alg_exit(void)
 477 {
 478         sock_unregister(PF_ALG);
 479         proto_unregister(&alg_proto);
 480 }
 481
 482 module_init(af_alg_init);
 483 module_exit(af_alg_exit);
 484 MODULE_LICENSE("GPL");
 485 MODULE_ALIAS_NETPROTO(AF_ALG);