1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * af_alg: User-space algorithm interface 4 * 5 * This file provides the user-space API for algorithms. 6 * 7 * Copyright (c) 2010 Herbert Xu <herbert@gondor.apana.org.au> 8 */ 9 10 #include <linux/atomic.h> 11 #include <linux/capability.h> 12 #include <crypto/if_alg.h> 13 #include <linux/crypto.h> 14 #include <linux/init.h> 15 #include <linux/kernel.h> 16 #include <linux/key.h> 17 #include <linux/key-type.h> 18 #include <linux/list.h> 19 #include <linux/module.h> 20 #include <linux/net.h> 21 #include <linux/rwsem.h> 22 #include <linux/sched.h> 23 #include <linux/sched/signal.h> 24 #include <linux/security.h> 25 #include <linux/string.h> 26 #include <linux/sysctl.h> 27 #include <linux/user_namespace.h> 28 #include <keys/user-type.h> 29 #include <keys/trusted-type.h> 30 #include <keys/encrypted-type.h> 31 32 static int af_alg_restrict = 1; 33 34 static const struct ctl_table af_alg_table[] = { 35 { 36 .procname = "af_alg_restrict", 37 .data = &af_alg_restrict, 38 .maxlen = sizeof(int), 39 .mode = 0644, 40 .proc_handler = proc_dointvec_minmax, 41 .extra1 = SYSCTL_ZERO, 42 .extra2 = SYSCTL_TWO, 43 }, 44 }; 45 46 static struct ctl_table_header *af_alg_header; 47 48 struct alg_type_list { 49 const struct af_alg_type *type; 50 struct list_head list; 51 }; 52 53 static struct proto alg_proto = { 54 .name = "ALG", 55 .owner = THIS_MODULE, 56 .obj_size = sizeof(struct alg_sock), 57 }; 58 59 static LIST_HEAD(alg_types); 60 static DECLARE_RWSEM(alg_types_sem); 61 62 static const struct af_alg_type *alg_get_type(const char *name) 63 { 64 const struct af_alg_type *type = ERR_PTR(-ENOENT); 65 struct alg_type_list *node; 66 67 down_read(&alg_types_sem); 68 list_for_each_entry(node, &alg_types, list) { 69 if (strcmp(node->type->name, name)) 70 continue; 71 72 if (try_module_get(node->type->owner)) 73 type = node->type; 74 break; 75 } 76 up_read(&alg_types_sem); 77 78 return type; 79 } 80 81 int af_alg_register_type(const struct af_alg_type *type) 82 { 83 struct alg_type_list *node; 84 int err = -EEXIST; 85 86 down_write(&alg_types_sem); 87 list_for_each_entry(node, &alg_types, list) { 88 if (!strcmp(node->type->name, type->name)) 89 goto unlock; 90 } 91 92 node = kmalloc_obj(*node); 93 err = -ENOMEM; 94 if (!node) 95 goto unlock; 96 97 type->ops->owner = THIS_MODULE; 98 if (type->ops_nokey) 99 type->ops_nokey->owner = THIS_MODULE; 100 node->type = type; 101 list_add(&node->list, &alg_types); 102 err = 0; 103 104 unlock: 105 up_write(&alg_types_sem); 106 107 return err; 108 } 109 EXPORT_SYMBOL_GPL(af_alg_register_type); 110 111 int af_alg_unregister_type(const struct af_alg_type *type) 112 { 113 struct alg_type_list *node; 114 int err = -ENOENT; 115 116 down_write(&alg_types_sem); 117 list_for_each_entry(node, &alg_types, list) { 118 if (strcmp(node->type->name, type->name)) 119 continue; 120 121 list_del(&node->list); 122 kfree(node); 123 err = 0; 124 break; 125 } 126 up_write(&alg_types_sem); 127 128 return err; 129 } 130 EXPORT_SYMBOL_GPL(af_alg_unregister_type); 131 132 static bool af_alg_capable(void) 133 { 134 return ns_capable_noaudit(&init_user_ns, CAP_NET_ADMIN) || 135 capable(CAP_SYS_ADMIN); 136 } 137 138 int af_alg_check_restriction(const char *name, 139 const struct af_alg_allowlist_entry allowlist[]) 140 { 141 int level = READ_ONCE(af_alg_restrict); 142 143 if (level == 0) 144 return 0; 145 if (level == 1) { 146 for (const struct af_alg_allowlist_entry *ent = allowlist; 147 ent->name; ent++) { 148 if (strcmp(name, ent->name) == 0 && 149 (!ent->privileged || af_alg_capable())) 150 return 0; 151 } 152 } 153 /* 154 * Use -ENOENT (the error code for "algorithm not found") instead of 155 * -EACCES or -EPERM, for the highest chance of correctly triggering 156 * fallback code paths in userspace programs. 157 * 158 * Don't log a warning, since it would be noisy. iwd tries to bind a 159 * bunch of algorithms that it never uses. 160 */ 161 return -ENOENT; 162 } 163 EXPORT_SYMBOL_GPL(af_alg_check_restriction); 164 165 static void alg_do_release(const struct af_alg_type *type, void *private) 166 { 167 if (!type) 168 return; 169 170 type->release(private); 171 module_put(type->owner); 172 } 173 174 int af_alg_release(struct socket *sock) 175 { 176 if (sock->sk) { 177 sock_put(sock->sk); 178 sock->sk = NULL; 179 } 180 return 0; 181 } 182 EXPORT_SYMBOL_GPL(af_alg_release); 183 184 void af_alg_release_parent(struct sock *sk) 185 { 186 struct alg_sock *ask = alg_sk(sk); 187 unsigned int nokey = atomic_read(&ask->nokey_refcnt); 188 189 sk = ask->parent; 190 ask = alg_sk(sk); 191 192 if (nokey) 193 atomic_dec(&ask->nokey_refcnt); 194 195 if (atomic_dec_and_test(&ask->refcnt)) 196 sock_put(sk); 197 } 198 EXPORT_SYMBOL_GPL(af_alg_release_parent); 199 200 static int alg_bind(struct socket *sock, struct sockaddr_unsized *uaddr, int addr_len) 201 { 202 const u32 allowed = CRYPTO_ALG_KERN_DRIVER_ONLY; 203 struct sock *sk = sock->sk; 204 struct alg_sock *ask = alg_sk(sk); 205 struct sockaddr_alg_new *sa = (void *)uaddr; 206 const struct af_alg_type *type; 207 void *private; 208 int err; 209 210 if (sock->state == SS_CONNECTED) 211 return -EINVAL; 212 213 BUILD_BUG_ON(offsetof(struct sockaddr_alg_new, salg_name) != 214 offsetof(struct sockaddr_alg, salg_name)); 215 BUILD_BUG_ON(offsetof(struct sockaddr_alg, salg_name) != sizeof(*sa)); 216 217 if (addr_len < sizeof(*sa) + 1) 218 return -EINVAL; 219 220 /* If caller uses non-allowed flag, return error. */ 221 if ((sa->salg_feat & ~allowed) || (sa->salg_mask & ~allowed)) 222 return -EINVAL; 223 224 sa->salg_type[sizeof(sa->salg_type) - 1] = 0; 225 sa->salg_name[addr_len - sizeof(*sa) - 1] = 0; 226 227 type = alg_get_type(sa->salg_type); 228 if (PTR_ERR(type) == -ENOENT) { 229 request_module("algif-%s", sa->salg_type); 230 type = alg_get_type(sa->salg_type); 231 } 232 233 if (IS_ERR(type)) 234 return PTR_ERR(type); 235 236 private = type->bind(sa->salg_name); 237 if (IS_ERR(private)) { 238 module_put(type->owner); 239 return PTR_ERR(private); 240 } 241 242 err = -EBUSY; 243 lock_sock(sk); 244 if (atomic_read(&ask->refcnt)) 245 goto unlock; 246 247 swap(ask->type, type); 248 swap(ask->private, private); 249 250 err = 0; 251 252 unlock: 253 release_sock(sk); 254 255 alg_do_release(type, private); 256 257 return err; 258 } 259 260 static int alg_setkey(struct sock *sk, sockptr_t ukey, unsigned int keylen) 261 { 262 struct alg_sock *ask = alg_sk(sk); 263 const struct af_alg_type *type = ask->type; 264 u8 *key; 265 int err; 266 267 key = sock_kmalloc(sk, keylen, GFP_KERNEL); 268 if (!key) 269 return -ENOMEM; 270 271 err = -EFAULT; 272 if (copy_from_sockptr(key, ukey, keylen)) 273 goto out; 274 275 err = type->setkey(ask->private, key, keylen); 276 277 out: 278 sock_kzfree_s(sk, key, keylen); 279 280 return err; 281 } 282 283 #ifdef CONFIG_KEYS 284 285 static const u8 *key_data_ptr_user(const struct key *key, 286 unsigned int *datalen) 287 { 288 const struct user_key_payload *ukp; 289 290 ukp = user_key_payload_locked(key); 291 if (IS_ERR_OR_NULL(ukp)) 292 return ERR_PTR(-EKEYREVOKED); 293 294 *datalen = key->datalen; 295 296 return ukp->data; 297 } 298 299 static const u8 *key_data_ptr_encrypted(const struct key *key, 300 unsigned int *datalen) 301 { 302 const struct encrypted_key_payload *ekp; 303 304 ekp = dereference_key_locked(key); 305 if (IS_ERR_OR_NULL(ekp)) 306 return ERR_PTR(-EKEYREVOKED); 307 308 *datalen = ekp->decrypted_datalen; 309 310 return ekp->decrypted_data; 311 } 312 313 static const u8 *key_data_ptr_trusted(const struct key *key, 314 unsigned int *datalen) 315 { 316 const struct trusted_key_payload *tkp; 317 318 tkp = dereference_key_locked(key); 319 if (IS_ERR_OR_NULL(tkp)) 320 return ERR_PTR(-EKEYREVOKED); 321 322 *datalen = tkp->key_len; 323 324 return tkp->key; 325 } 326 327 static struct key *lookup_key(key_serial_t serial) 328 { 329 key_ref_t key_ref; 330 331 key_ref = lookup_user_key(serial, 0, KEY_NEED_SEARCH); 332 if (IS_ERR(key_ref)) 333 return ERR_CAST(key_ref); 334 335 return key_ref_to_ptr(key_ref); 336 } 337 338 static int alg_setkey_by_key_serial(struct alg_sock *ask, sockptr_t optval, 339 unsigned int optlen) 340 { 341 const struct af_alg_type *type = ask->type; 342 u8 *key_data = NULL; 343 unsigned int key_datalen; 344 key_serial_t serial; 345 struct key *key; 346 const u8 *ret; 347 int err; 348 349 if (optlen != sizeof(serial)) 350 return -EINVAL; 351 352 if (copy_from_sockptr(&serial, optval, optlen)) 353 return -EFAULT; 354 355 key = lookup_key(serial); 356 if (IS_ERR(key)) 357 return PTR_ERR(key); 358 359 down_read(&key->sem); 360 361 ret = ERR_PTR(-ENOPROTOOPT); 362 if (!strcmp(key->type->name, "user") || 363 !strcmp(key->type->name, "logon")) { 364 ret = key_data_ptr_user(key, &key_datalen); 365 } else if (IS_REACHABLE(CONFIG_ENCRYPTED_KEYS) && 366 !strcmp(key->type->name, "encrypted")) { 367 ret = key_data_ptr_encrypted(key, &key_datalen); 368 } else if (IS_REACHABLE(CONFIG_TRUSTED_KEYS) && 369 !strcmp(key->type->name, "trusted")) { 370 ret = key_data_ptr_trusted(key, &key_datalen); 371 } 372 373 if (IS_ERR(ret)) { 374 up_read(&key->sem); 375 key_put(key); 376 return PTR_ERR(ret); 377 } 378 379 key_data = sock_kmemdup(&ask->sk, ret, key_datalen, GFP_KERNEL); 380 if (!key_data) { 381 up_read(&key->sem); 382 key_put(key); 383 return -ENOMEM; 384 } 385 386 up_read(&key->sem); 387 key_put(key); 388 389 err = type->setkey(ask->private, key_data, key_datalen); 390 391 sock_kzfree_s(&ask->sk, key_data, key_datalen); 392 393 return err; 394 } 395 396 #else 397 398 static inline int alg_setkey_by_key_serial(struct alg_sock *ask, 399 sockptr_t optval, 400 unsigned int optlen) 401 { 402 return -ENOPROTOOPT; 403 } 404 405 #endif 406 407 static int alg_setsockopt(struct socket *sock, int level, int optname, 408 sockptr_t optval, unsigned int optlen) 409 { 410 struct sock *sk = sock->sk; 411 struct alg_sock *ask = alg_sk(sk); 412 const struct af_alg_type *type; 413 int err = -EBUSY; 414 415 lock_sock(sk); 416 if (atomic_read(&ask->refcnt) != atomic_read(&ask->nokey_refcnt)) 417 goto unlock; 418 419 type = ask->type; 420 421 err = -ENOPROTOOPT; 422 if (level != SOL_ALG || !type) 423 goto unlock; 424 425 switch (optname) { 426 case ALG_SET_KEY: 427 case ALG_SET_KEY_BY_KEY_SERIAL: 428 if (sock->state == SS_CONNECTED) 429 goto unlock; 430 if (!type->setkey) 431 goto unlock; 432 433 if (optname == ALG_SET_KEY_BY_KEY_SERIAL) 434 err = alg_setkey_by_key_serial(ask, optval, optlen); 435 else 436 err = alg_setkey(sk, optval, optlen); 437 break; 438 case ALG_SET_AEAD_AUTHSIZE: 439 if (sock->state == SS_CONNECTED) 440 goto unlock; 441 if (!type->setauthsize) 442 goto unlock; 443 err = type->setauthsize(ask->private, optlen); 444 break; 445 case ALG_SET_DRBG_ENTROPY: 446 if (sock->state == SS_CONNECTED) 447 goto unlock; 448 if (!type->setentropy) 449 goto unlock; 450 451 err = type->setentropy(ask->private, optval, optlen); 452 } 453 454 unlock: 455 release_sock(sk); 456 457 return err; 458 } 459 460 int af_alg_accept(struct sock *sk, struct socket *newsock, 461 struct proto_accept_arg *arg) 462 { 463 struct alg_sock *ask = alg_sk(sk); 464 const struct af_alg_type *type; 465 struct sock *sk2; 466 unsigned int nokey; 467 int err; 468 469 lock_sock(sk); 470 type = ask->type; 471 472 err = -EINVAL; 473 if (!type) 474 goto unlock; 475 476 sk2 = sk_alloc(sock_net(sk), PF_ALG, GFP_KERNEL, &alg_proto, arg->kern); 477 err = -ENOMEM; 478 if (!sk2) 479 goto unlock; 480 481 sock_init_data(newsock, sk2); 482 security_sock_graft(sk2, newsock); 483 security_sk_clone(sk, sk2); 484 485 /* 486 * newsock->ops assigned here to allow type->accept call to override 487 * them when required. 488 */ 489 newsock->ops = type->ops; 490 err = type->accept(ask->private, sk2); 491 492 nokey = err == -ENOKEY; 493 if (nokey && type->accept_nokey) 494 err = type->accept_nokey(ask->private, sk2); 495 496 if (err) 497 goto unlock; 498 499 if (atomic_inc_return_relaxed(&ask->refcnt) == 1) 500 sock_hold(sk); 501 if (nokey) { 502 atomic_inc(&ask->nokey_refcnt); 503 atomic_set(&alg_sk(sk2)->nokey_refcnt, 1); 504 } 505 alg_sk(sk2)->parent = sk; 506 alg_sk(sk2)->type = type; 507 508 newsock->state = SS_CONNECTED; 509 510 if (nokey) 511 newsock->ops = type->ops_nokey; 512 513 err = 0; 514 515 unlock: 516 release_sock(sk); 517 518 return err; 519 } 520 EXPORT_SYMBOL_GPL(af_alg_accept); 521 522 static int alg_accept(struct socket *sock, struct socket *newsock, 523 struct proto_accept_arg *arg) 524 { 525 return af_alg_accept(sock->sk, newsock, arg); 526 } 527 528 static const struct proto_ops alg_proto_ops = { 529 .family = PF_ALG, 530 .owner = THIS_MODULE, 531 532 .connect = sock_no_connect, 533 .socketpair = sock_no_socketpair, 534 .getname = sock_no_getname, 535 .ioctl = sock_no_ioctl, 536 .listen = sock_no_listen, 537 .shutdown = sock_no_shutdown, 538 .mmap = sock_no_mmap, 539 .sendmsg = sock_no_sendmsg, 540 .recvmsg = sock_no_recvmsg, 541 542 .bind = alg_bind, 543 .release = af_alg_release, 544 .setsockopt = alg_setsockopt, 545 .accept = alg_accept, 546 }; 547 548 static void alg_sock_destruct(struct sock *sk) 549 { 550 struct alg_sock *ask = alg_sk(sk); 551 552 alg_do_release(ask->type, ask->private); 553 } 554 555 static int alg_create(struct net *net, struct socket *sock, int protocol, 556 int kern) 557 { 558 struct sock *sk; 559 int err; 560 561 if (READ_ONCE(af_alg_restrict) == 2) 562 return -EAFNOSUPPORT; 563 564 if (sock->type != SOCK_SEQPACKET) 565 return -ESOCKTNOSUPPORT; 566 if (protocol != 0) 567 return -EPROTONOSUPPORT; 568 569 err = -ENOMEM; 570 sk = sk_alloc(net, PF_ALG, GFP_KERNEL, &alg_proto, kern); 571 if (!sk) 572 goto out; 573 574 sock->ops = &alg_proto_ops; 575 sock_init_data(sock, sk); 576 577 sk->sk_destruct = alg_sock_destruct; 578 579 return 0; 580 out: 581 return err; 582 } 583 584 static const struct net_proto_family alg_family = { 585 .family = PF_ALG, 586 .create = alg_create, 587 .owner = THIS_MODULE, 588 }; 589 590 static void af_alg_link_sg(struct af_alg_sgl *sgl_prev, 591 struct af_alg_sgl *sgl_new) 592 { 593 sg_unmark_end(sgl_prev->sgt.sgl + sgl_prev->sgt.nents - 1); 594 sg_chain(sgl_prev->sgt.sgl, sgl_prev->sgt.nents + 1, sgl_new->sgt.sgl); 595 } 596 597 void af_alg_free_sg(struct af_alg_sgl *sgl) 598 { 599 int i; 600 601 if (sgl->sgt.sgl) { 602 if (sgl->need_unpin) 603 for (i = 0; i < sgl->sgt.nents; i++) 604 unpin_user_page(sg_page(&sgl->sgt.sgl[i])); 605 if (sgl->sgt.sgl != sgl->sgl) 606 kvfree(sgl->sgt.sgl); 607 sgl->sgt.sgl = NULL; 608 } 609 } 610 EXPORT_SYMBOL_GPL(af_alg_free_sg); 611 612 static int af_alg_cmsg_send(struct msghdr *msg, struct af_alg_control *con) 613 { 614 struct cmsghdr *cmsg; 615 616 for_each_cmsghdr(cmsg, msg) { 617 if (!CMSG_OK(msg, cmsg)) 618 return -EINVAL; 619 if (cmsg->cmsg_level != SOL_ALG) 620 continue; 621 622 switch (cmsg->cmsg_type) { 623 case ALG_SET_IV: 624 if (cmsg->cmsg_len < CMSG_LEN(sizeof(*con->iv))) 625 return -EINVAL; 626 con->iv = (void *)CMSG_DATA(cmsg); 627 if (cmsg->cmsg_len < CMSG_LEN(con->iv->ivlen + 628 sizeof(*con->iv))) 629 return -EINVAL; 630 break; 631 632 case ALG_SET_OP: 633 if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32))) 634 return -EINVAL; 635 con->op = *(u32 *)CMSG_DATA(cmsg); 636 break; 637 638 case ALG_SET_AEAD_ASSOCLEN: 639 if (cmsg->cmsg_len < CMSG_LEN(sizeof(u32))) 640 return -EINVAL; 641 con->aead_assoclen = *(u32 *)CMSG_DATA(cmsg); 642 if (con->aead_assoclen >= 0x80000000u) 643 return -EINVAL; 644 break; 645 646 default: 647 return -EINVAL; 648 } 649 } 650 651 return 0; 652 } 653 654 /** 655 * af_alg_alloc_tsgl - allocate the TX SGL 656 * 657 * @sk: socket of connection to user space 658 * Return: 0 upon success, < 0 upon error 659 */ 660 static int af_alg_alloc_tsgl(struct sock *sk) 661 { 662 struct alg_sock *ask = alg_sk(sk); 663 struct af_alg_ctx *ctx = ask->private; 664 struct af_alg_tsgl *sgl; 665 struct scatterlist *sg = NULL; 666 667 sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl, list); 668 if (!list_empty(&ctx->tsgl_list)) 669 sg = sgl->sg; 670 671 if (!sg || sgl->cur >= MAX_SGL_ENTS) { 672 sgl = sock_kmalloc(sk, 673 struct_size(sgl, sg, (MAX_SGL_ENTS + 1)), 674 GFP_KERNEL); 675 if (!sgl) 676 return -ENOMEM; 677 678 sg_init_table(sgl->sg, MAX_SGL_ENTS + 1); 679 sgl->cur = 0; 680 681 if (sg) { 682 sg_unmark_end(sg + MAX_SGL_ENTS - 1); 683 sg_chain(sg, MAX_SGL_ENTS + 1, sgl->sg); 684 } 685 686 list_add_tail(&sgl->list, &ctx->tsgl_list); 687 } 688 689 return 0; 690 } 691 692 /** 693 * af_alg_count_tsgl - Count number of TX SG entries 694 * 695 * The counting starts from the beginning of the SGL to @bytes. 696 * 697 * @sk: socket of connection to user space 698 * @bytes: Count the number of SG entries holding given number of bytes. 699 * Return: Number of TX SG entries found given the constraints 700 */ 701 unsigned int af_alg_count_tsgl(struct sock *sk, size_t bytes) 702 { 703 const struct alg_sock *ask = alg_sk(sk); 704 const struct af_alg_ctx *ctx = ask->private; 705 const struct af_alg_tsgl *sgl; 706 unsigned int i; 707 unsigned int sgl_count = 0; 708 709 if (!bytes) 710 return 0; 711 712 list_for_each_entry(sgl, &ctx->tsgl_list, list) { 713 const struct scatterlist *sg = sgl->sg; 714 715 for (i = 0; i < sgl->cur; i++) { 716 sgl_count++; 717 if (sg[i].length >= bytes) 718 return sgl_count; 719 720 bytes -= sg[i].length; 721 } 722 } 723 724 return sgl_count; 725 } 726 EXPORT_SYMBOL_GPL(af_alg_count_tsgl); 727 728 /** 729 * af_alg_pull_tsgl - Release the specified buffers from TX SGL 730 * 731 * If @dst is non-null, reassign the pages to @dst. The caller must release 732 * the pages. 733 * 734 * @sk: socket of connection to user space 735 * @used: Number of bytes to pull from TX SGL 736 * @dst: If non-NULL, buffer is reassigned to dst SGL instead of releasing. The 737 * caller must release the buffers in dst. 738 */ 739 void af_alg_pull_tsgl(struct sock *sk, size_t used, struct scatterlist *dst) 740 { 741 struct alg_sock *ask = alg_sk(sk); 742 struct af_alg_ctx *ctx = ask->private; 743 struct af_alg_tsgl *sgl; 744 struct scatterlist *sg; 745 unsigned int i, j = 0; 746 747 while (!list_empty(&ctx->tsgl_list)) { 748 sgl = list_first_entry(&ctx->tsgl_list, struct af_alg_tsgl, 749 list); 750 sg = sgl->sg; 751 752 for (i = 0; i < sgl->cur; i++) { 753 size_t plen = min_t(size_t, used, sg[i].length); 754 struct page *page = sg_page(sg + i); 755 756 if (!page) 757 continue; 758 759 /* 760 * Assumption: caller created af_alg_count_tsgl(len) 761 * SG entries in dst. 762 */ 763 if (dst && plen) { 764 /* reassign page to dst */ 765 get_page(page); 766 sg_set_page(dst + j, page, plen, sg[i].offset); 767 j++; 768 } 769 770 sg[i].length -= plen; 771 sg[i].offset += plen; 772 773 used -= plen; 774 ctx->used -= plen; 775 776 if (sg[i].length) 777 return; 778 779 put_page(page); 780 sg_assign_page(sg + i, NULL); 781 } 782 783 list_del(&sgl->list); 784 sock_kfree_s(sk, sgl, struct_size(sgl, sg, MAX_SGL_ENTS + 1)); 785 } 786 787 if (!ctx->used) 788 ctx->merge = 0; 789 ctx->init = ctx->more; 790 } 791 EXPORT_SYMBOL_GPL(af_alg_pull_tsgl); 792 793 /** 794 * af_alg_free_areq_sgls - Release TX and RX SGLs of the request 795 * 796 * @areq: Request holding the TX and RX SGL 797 */ 798 static void af_alg_free_areq_sgls(struct af_alg_async_req *areq) 799 { 800 struct sock *sk = areq->sk; 801 struct alg_sock *ask = alg_sk(sk); 802 struct af_alg_ctx *ctx = ask->private; 803 struct af_alg_rsgl *rsgl, *tmp; 804 struct scatterlist *tsgl; 805 struct scatterlist *sg; 806 unsigned int i; 807 808 list_for_each_entry_safe(rsgl, tmp, &areq->rsgl_list, list) { 809 atomic_sub(rsgl->sg_num_bytes, &ctx->rcvused); 810 af_alg_free_sg(&rsgl->sgl); 811 list_del(&rsgl->list); 812 if (rsgl != &areq->first_rsgl) 813 sock_kfree_s(sk, rsgl, sizeof(*rsgl)); 814 } 815 816 tsgl = areq->tsgl; 817 if (tsgl) { 818 for_each_sg(tsgl, sg, areq->tsgl_entries, i) { 819 if (!sg_page(sg)) 820 continue; 821 put_page(sg_page(sg)); 822 } 823 824 sock_kfree_s(sk, tsgl, areq->tsgl_entries * sizeof(*tsgl)); 825 } 826 } 827 828 /** 829 * af_alg_wait_for_wmem - wait for availability of writable memory 830 * 831 * @sk: socket of connection to user space 832 * @flags: If MSG_DONTWAIT is set, then only report if function would sleep 833 * Return: 0 when writable memory is available, < 0 upon error 834 */ 835 static int af_alg_wait_for_wmem(struct sock *sk, unsigned int flags) 836 { 837 DEFINE_WAIT_FUNC(wait, woken_wake_function); 838 int err = -ERESTARTSYS; 839 long timeout; 840 841 if (flags & MSG_DONTWAIT) 842 return -EAGAIN; 843 844 sk_set_bit(SOCKWQ_ASYNC_NOSPACE, sk); 845 846 add_wait_queue(sk_sleep(sk), &wait); 847 for (;;) { 848 if (signal_pending(current)) 849 break; 850 timeout = MAX_SCHEDULE_TIMEOUT; 851 if (sk_wait_event(sk, &timeout, af_alg_writable(sk), &wait)) { 852 err = 0; 853 break; 854 } 855 } 856 remove_wait_queue(sk_sleep(sk), &wait); 857 858 return err; 859 } 860 861 /** 862 * af_alg_wmem_wakeup - wakeup caller when writable memory is available 863 * 864 * @sk: socket of connection to user space 865 */ 866 void af_alg_wmem_wakeup(struct sock *sk) 867 { 868 struct socket_wq *wq; 869 870 if (!af_alg_writable(sk)) 871 return; 872 873 rcu_read_lock(); 874 wq = rcu_dereference(sk->sk_wq); 875 if (skwq_has_sleeper(wq)) 876 wake_up_interruptible_sync_poll(&wq->wait, EPOLLIN | 877 EPOLLRDNORM | 878 EPOLLRDBAND); 879 sk_wake_async_rcu(sk, SOCK_WAKE_WAITD, POLL_IN); 880 rcu_read_unlock(); 881 } 882 EXPORT_SYMBOL_GPL(af_alg_wmem_wakeup); 883 884 /** 885 * af_alg_wait_for_data - wait for availability of TX data 886 * 887 * @sk: socket of connection to user space 888 * @flags: If MSG_DONTWAIT is set, then only report if function would sleep 889 * @min: Set to minimum request size if partial requests are allowed. 890 * Return: 0 when writable memory is available, < 0 upon error 891 */ 892 int af_alg_wait_for_data(struct sock *sk, unsigned flags, unsigned min) 893 { 894 DEFINE_WAIT_FUNC(wait, woken_wake_function); 895 struct alg_sock *ask = alg_sk(sk); 896 struct af_alg_ctx *ctx = ask->private; 897 long timeout; 898 int err = -ERESTARTSYS; 899 900 if (flags & MSG_DONTWAIT) 901 return -EAGAIN; 902 903 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); 904 905 add_wait_queue(sk_sleep(sk), &wait); 906 for (;;) { 907 if (signal_pending(current)) 908 break; 909 timeout = MAX_SCHEDULE_TIMEOUT; 910 if (sk_wait_event(sk, &timeout, 911 ctx->init && (!ctx->more || 912 (min && ctx->used >= min)), 913 &wait)) { 914 err = 0; 915 break; 916 } 917 } 918 remove_wait_queue(sk_sleep(sk), &wait); 919 920 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk); 921 922 return err; 923 } 924 EXPORT_SYMBOL_GPL(af_alg_wait_for_data); 925 926 /** 927 * af_alg_data_wakeup - wakeup caller when new data can be sent to kernel 928 * 929 * @sk: socket of connection to user space 930 */ 931 static void af_alg_data_wakeup(struct sock *sk) 932 { 933 struct alg_sock *ask = alg_sk(sk); 934 struct af_alg_ctx *ctx = ask->private; 935 struct socket_wq *wq; 936 937 if (!ctx->used) 938 return; 939 940 rcu_read_lock(); 941 wq = rcu_dereference(sk->sk_wq); 942 if (skwq_has_sleeper(wq)) 943 wake_up_interruptible_sync_poll(&wq->wait, EPOLLOUT | 944 EPOLLRDNORM | 945 EPOLLRDBAND); 946 sk_wake_async_rcu(sk, SOCK_WAKE_SPACE, POLL_OUT); 947 rcu_read_unlock(); 948 } 949 950 /** 951 * af_alg_sendmsg - implementation of sendmsg system call handler 952 * 953 * The sendmsg system call handler obtains the user data and stores it 954 * in ctx->tsgl_list. This implies allocation of the required numbers of 955 * struct af_alg_tsgl. 956 * 957 * In addition, the ctx is filled with the information sent via CMSG. 958 * 959 * @sock: socket of connection to user space 960 * @msg: message from user space 961 * @size: size of message from user space 962 * @ivsize: the size of the IV for the cipher operation to verify that the 963 * user-space-provided IV has the right size 964 * Return: the number of copied data upon success, < 0 upon error 965 */ 966 int af_alg_sendmsg(struct socket *sock, struct msghdr *msg, size_t size, 967 unsigned int ivsize) 968 { 969 struct sock *sk = sock->sk; 970 struct alg_sock *ask = alg_sk(sk); 971 struct af_alg_ctx *ctx = ask->private; 972 struct af_alg_tsgl *sgl; 973 struct af_alg_control con = {}; 974 long copied = 0; 975 bool enc = false; 976 bool init = false; 977 int err = 0; 978 979 if (msg->msg_controllen) { 980 err = af_alg_cmsg_send(msg, &con); 981 if (err) 982 return err; 983 984 init = true; 985 switch (con.op) { 986 case ALG_OP_ENCRYPT: 987 enc = true; 988 break; 989 case ALG_OP_DECRYPT: 990 enc = false; 991 break; 992 default: 993 return -EINVAL; 994 } 995 996 if (con.iv && con.iv->ivlen != ivsize) 997 return -EINVAL; 998 } 999 1000 lock_sock(sk); 1001 if (ctx->write) { 1002 release_sock(sk); 1003 return -EBUSY; 1004 } 1005 ctx->write = true; 1006 1007 if (ctx->init && !ctx->more) { 1008 if (ctx->used) { 1009 err = -EINVAL; 1010 goto unlock; 1011 } 1012 1013 pr_info_once( 1014 "%s sent an empty control message without MSG_MORE.\n", 1015 current->comm); 1016 } 1017 ctx->init = true; 1018 1019 if (init) { 1020 ctx->enc = enc; 1021 if (con.iv) 1022 memcpy(ctx->iv, con.iv->iv, ivsize); 1023 1024 ctx->aead_assoclen = con.aead_assoclen; 1025 } 1026 1027 while (size) { 1028 struct scatterlist *sg; 1029 size_t len = size; 1030 ssize_t plen; 1031 1032 /* use the existing memory in an allocated page */ 1033 if (ctx->merge) { 1034 sgl = list_entry(ctx->tsgl_list.prev, 1035 struct af_alg_tsgl, list); 1036 sg = sgl->sg + sgl->cur - 1; 1037 len = min_t(size_t, len, 1038 PAGE_SIZE - sg->offset - sg->length); 1039 1040 err = memcpy_from_msg(page_address(sg_page(sg)) + 1041 sg->offset + sg->length, 1042 msg, len); 1043 if (err) 1044 goto unlock; 1045 1046 sg->length += len; 1047 ctx->merge = (sg->offset + sg->length) & 1048 (PAGE_SIZE - 1); 1049 1050 ctx->used += len; 1051 copied += len; 1052 size -= len; 1053 continue; 1054 } 1055 1056 ctx->merge = 0; 1057 1058 if (!af_alg_writable(sk)) { 1059 err = af_alg_wait_for_wmem(sk, msg->msg_flags); 1060 if (err) 1061 goto unlock; 1062 } 1063 1064 /* allocate a new page */ 1065 len = min_t(unsigned long, len, af_alg_sndbuf(sk)); 1066 1067 err = af_alg_alloc_tsgl(sk); 1068 if (err) 1069 goto unlock; 1070 1071 sgl = list_entry(ctx->tsgl_list.prev, struct af_alg_tsgl, 1072 list); 1073 sg = sgl->sg; 1074 if (sgl->cur) 1075 sg_unmark_end(sg + sgl->cur - 1); 1076 1077 do { 1078 struct page *pg; 1079 unsigned int i = sgl->cur; 1080 1081 plen = min_t(size_t, len, PAGE_SIZE); 1082 1083 pg = alloc_page(GFP_KERNEL); 1084 if (!pg) { 1085 err = -ENOMEM; 1086 goto unlock; 1087 } 1088 1089 sg_assign_page(sg + i, pg); 1090 1091 err = memcpy_from_msg(page_address(sg_page(sg + i)), 1092 msg, plen); 1093 if (err) { 1094 __free_page(sg_page(sg + i)); 1095 sg_assign_page(sg + i, NULL); 1096 goto unlock; 1097 } 1098 1099 sg[i].length = plen; 1100 len -= plen; 1101 ctx->used += plen; 1102 copied += plen; 1103 size -= plen; 1104 sgl->cur++; 1105 } while (len && sgl->cur < MAX_SGL_ENTS); 1106 1107 ctx->merge = plen & (PAGE_SIZE - 1); 1108 1109 if (!size) 1110 sg_mark_end(sg + sgl->cur - 1); 1111 } 1112 1113 err = 0; 1114 1115 ctx->more = msg->msg_flags & MSG_MORE; 1116 1117 unlock: 1118 af_alg_data_wakeup(sk); 1119 ctx->write = false; 1120 release_sock(sk); 1121 1122 return copied ?: err; 1123 } 1124 EXPORT_SYMBOL_GPL(af_alg_sendmsg); 1125 1126 /** 1127 * af_alg_free_resources - release resources required for crypto request 1128 * @areq: Request holding the TX and RX SGL 1129 */ 1130 void af_alg_free_resources(struct af_alg_async_req *areq) 1131 { 1132 struct sock *sk = areq->sk; 1133 struct af_alg_ctx *ctx; 1134 1135 af_alg_free_areq_sgls(areq); 1136 sock_kfree_s(sk, areq, areq->areqlen); 1137 1138 ctx = alg_sk(sk)->private; 1139 ctx->inflight = false; 1140 } 1141 EXPORT_SYMBOL_GPL(af_alg_free_resources); 1142 1143 /** 1144 * af_alg_poll - poll system call handler 1145 * @file: file pointer 1146 * @sock: socket to poll 1147 * @wait: poll_table 1148 */ 1149 __poll_t af_alg_poll(struct file *file, struct socket *sock, 1150 poll_table *wait) 1151 { 1152 struct sock *sk = sock->sk; 1153 struct alg_sock *ask = alg_sk(sk); 1154 struct af_alg_ctx *ctx = ask->private; 1155 __poll_t mask; 1156 1157 sock_poll_wait(file, sock, wait); 1158 mask = 0; 1159 1160 if (!ctx->more || ctx->used) 1161 mask |= EPOLLIN | EPOLLRDNORM; 1162 1163 if (af_alg_writable(sk)) 1164 mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND; 1165 1166 return mask; 1167 } 1168 EXPORT_SYMBOL_GPL(af_alg_poll); 1169 1170 /** 1171 * af_alg_alloc_areq - allocate struct af_alg_async_req 1172 * 1173 * @sk: socket of connection to user space 1174 * @areqlen: size of struct af_alg_async_req + crypto_*_reqsize 1175 * Return: allocated data structure or ERR_PTR upon error 1176 */ 1177 struct af_alg_async_req *af_alg_alloc_areq(struct sock *sk, 1178 unsigned int areqlen) 1179 { 1180 struct af_alg_ctx *ctx = alg_sk(sk)->private; 1181 struct af_alg_async_req *areq; 1182 1183 /* Only one request can be in flight. */ 1184 if (WARN_ON_ONCE(ctx->inflight)) 1185 return ERR_PTR(-EBUSY); 1186 1187 areq = sock_kmalloc(sk, areqlen, GFP_KERNEL); 1188 if (unlikely(!areq)) 1189 return ERR_PTR(-ENOMEM); 1190 1191 memset(areq, 0, areqlen); 1192 1193 ctx->inflight = true; 1194 1195 areq->areqlen = areqlen; 1196 areq->sk = sk; 1197 areq->first_rsgl.sgl.sgt.sgl = areq->first_rsgl.sgl.sgl; 1198 INIT_LIST_HEAD(&areq->rsgl_list); 1199 1200 return areq; 1201 } 1202 EXPORT_SYMBOL_GPL(af_alg_alloc_areq); 1203 1204 /** 1205 * af_alg_get_rsgl - create the RX SGL for the output data from the crypto 1206 * operation 1207 * 1208 * @sk: socket of connection to user space 1209 * @msg: user space message 1210 * @flags: flags used to invoke recvmsg with 1211 * @areq: instance of the cryptographic request that will hold the RX SGL 1212 * @maxsize: maximum number of bytes to be pulled from user space 1213 * @outlen: number of bytes in the RX SGL 1214 * Return: 0 on success, < 0 upon error 1215 */ 1216 int af_alg_get_rsgl(struct sock *sk, struct msghdr *msg, int flags, 1217 struct af_alg_async_req *areq, size_t maxsize, 1218 size_t *outlen) 1219 { 1220 struct alg_sock *ask = alg_sk(sk); 1221 struct af_alg_ctx *ctx = ask->private; 1222 size_t len = 0; 1223 1224 while (maxsize > len && msg_data_left(msg)) { 1225 struct af_alg_rsgl *rsgl; 1226 ssize_t err; 1227 size_t seglen; 1228 1229 /* limit the amount of readable buffers */ 1230 if (!af_alg_readable(sk)) 1231 break; 1232 1233 seglen = min_t(size_t, (maxsize - len), 1234 msg_data_left(msg)); 1235 /* Never pin more pages than the remaining RX accounting budget. */ 1236 seglen = min_t(size_t, seglen, af_alg_rcvbuf(sk)); 1237 1238 if (list_empty(&areq->rsgl_list)) { 1239 rsgl = &areq->first_rsgl; 1240 } else { 1241 rsgl = sock_kmalloc(sk, sizeof(*rsgl), GFP_KERNEL); 1242 if (unlikely(!rsgl)) 1243 return -ENOMEM; 1244 } 1245 1246 rsgl->sgl.need_unpin = 1247 iov_iter_extract_will_pin(&msg->msg_iter); 1248 rsgl->sgl.sgt.sgl = rsgl->sgl.sgl; 1249 rsgl->sgl.sgt.nents = 0; 1250 rsgl->sgl.sgt.orig_nents = 0; 1251 list_add_tail(&rsgl->list, &areq->rsgl_list); 1252 1253 sg_init_table(rsgl->sgl.sgt.sgl, ALG_MAX_PAGES); 1254 err = extract_iter_to_sg(&msg->msg_iter, seglen, &rsgl->sgl.sgt, 1255 ALG_MAX_PAGES, 0); 1256 if (err < 0) { 1257 rsgl->sg_num_bytes = 0; 1258 return err; 1259 } 1260 1261 sg_mark_end(rsgl->sgl.sgt.sgl + rsgl->sgl.sgt.nents - 1); 1262 1263 /* chain the new scatterlist with previous one */ 1264 if (areq->last_rsgl) 1265 af_alg_link_sg(&areq->last_rsgl->sgl, &rsgl->sgl); 1266 1267 areq->last_rsgl = rsgl; 1268 len += err; 1269 atomic_add(err, &ctx->rcvused); 1270 rsgl->sg_num_bytes = err; 1271 } 1272 1273 *outlen = len; 1274 return 0; 1275 } 1276 EXPORT_SYMBOL_GPL(af_alg_get_rsgl); 1277 1278 static int __init af_alg_init(void) 1279 { 1280 int err; 1281 1282 af_alg_header = register_sysctl("crypto", af_alg_table); 1283 1284 err = proto_register(&alg_proto, 0); 1285 if (err) 1286 goto out_unregister_sysctl; 1287 1288 err = sock_register(&alg_family); 1289 if (err) 1290 goto out_unregister_proto; 1291 1292 return 0; 1293 1294 out_unregister_proto: 1295 proto_unregister(&alg_proto); 1296 out_unregister_sysctl: 1297 unregister_sysctl_table(af_alg_header); 1298 return err; 1299 } 1300 1301 static void __exit af_alg_exit(void) 1302 { 1303 sock_unregister(PF_ALG); 1304 proto_unregister(&alg_proto); 1305 unregister_sysctl_table(af_alg_header); 1306 } 1307 1308 module_init(af_alg_init); 1309 module_exit(af_alg_exit); 1310 MODULE_DESCRIPTION("Crypto userspace interface"); 1311 MODULE_LICENSE("GPL"); 1312 MODULE_ALIAS_NETPROTO(AF_ALG); 1313