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 reinit_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); 486