crypto/crypto_user.c

   1 /*
   2  * Crypto user configuration API.
   3  *
   4  * Copyright (C) 2011 secunet Security Networks AG
   5  * Copyright (C) 2011 Steffen Klassert <steffen.klassert@secunet.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms and conditions of the GNU General Public License,
   9  * version 2, as published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  14  * more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along with
  17  * this program; if not, write to the Free Software Foundation, Inc.,
  18  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  19  */
  20
  21 #include <linux/module.h>
  22 #include <linux/crypto.h>
  23 #include <linux/cryptouser.h>
  24 #include <linux/sched.h>
  25 #include <net/netlink.h>
  26 #include <linux/security.h>
  27 #include <net/net_namespace.h>
  28 #include <crypto/internal/aead.h>
  29 #include <crypto/internal/skcipher.h>
  30 #include <crypto/internal/rng.h>
  31 #include <crypto/akcipher.h>
  32
  33 #include "internal.h"
  34
  35 #define null_terminated(x)      (strnlen(x, sizeof(x)) < sizeof(x))
  36
  37 static DEFINE_MUTEX(crypto_cfg_mutex);
  38
  39 /* The crypto netlink socket */
  40 static struct sock *crypto_nlsk;
  41
  42 struct crypto_dump_info {
  43         struct sk_buff *in_skb;
  44         struct sk_buff *out_skb;
  45         u32 nlmsg_seq;
  46         u16 nlmsg_flags;
  47 };
  48
  49 static struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
  50 {
  51         struct crypto_alg *q, *alg = NULL;
  52
  53         down_read(&crypto_alg_sem);
  54
  55         list_for_each_entry(q, &crypto_alg_list, cra_list) {
  56                 int match = 0;
  57
  58                 if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
  59                         continue;
  60
  61                 if (strlen(p->cru_driver_name))
  62                         match = !strcmp(q->cra_driver_name,
  63                                         p->cru_driver_name);
  64                 else if (!exact)
  65                         match = !strcmp(q->cra_name, p->cru_name);
  66
  67                 if (!match)
  68                         continue;
  69
  70                 if (unlikely(!crypto_mod_get(q)))
  71                         continue;
  72
  73                 alg = q;
  74                 break;
  75         }
  76
  77         up_read(&crypto_alg_sem);
  78
  79         return alg;
  80 }
  81
  82 static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
  83 {
  84         struct crypto_report_cipher rcipher;
  85
  86         strncpy(rcipher.type, "cipher", sizeof(rcipher.type));
  87
  88         rcipher.blocksize = alg->cra_blocksize;
  89         rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
  90         rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
  91
  92         if (nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
  93                     sizeof(struct crypto_report_cipher), &rcipher))
  94                 goto nla_put_failure;
  95         return 0;
  96
  97 nla_put_failure:
  98         return -EMSGSIZE;
  99 }
 100
 101 static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
 102 {
 103         struct crypto_report_comp rcomp;
 104
 105         strncpy(rcomp.type, "compression", sizeof(rcomp.type));
 106         if (nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS,
 107                     sizeof(struct crypto_report_comp), &rcomp))
 108                 goto nla_put_failure;
 109         return 0;
 110
 111 nla_put_failure:
 112         return -EMSGSIZE;
 113 }
 114
 115 static int crypto_report_akcipher(struct sk_buff *skb, struct crypto_alg *alg)
 116 {
 117         struct crypto_report_akcipher rakcipher;
 118
 119         strncpy(rakcipher.type, "akcipher", sizeof(rakcipher.type));
 120
 121         if (nla_put(skb, CRYPTOCFGA_REPORT_AKCIPHER,
 122                     sizeof(struct crypto_report_akcipher), &rakcipher))
 123                 goto nla_put_failure;
 124         return 0;
 125
 126 nla_put_failure:
 127         return -EMSGSIZE;
 128 }
 129
 130 static int crypto_report_one(struct crypto_alg *alg,
 131                              struct crypto_user_alg *ualg, struct sk_buff *skb)
 132 {
 133         strncpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
 134         strncpy(ualg->cru_driver_name, alg->cra_driver_name,
 135                 sizeof(ualg->cru_driver_name));
 136         strncpy(ualg->cru_module_name, module_name(alg->cra_module),
 137                 sizeof(ualg->cru_module_name));
 138
 139         ualg->cru_type = 0;
 140         ualg->cru_mask = 0;
 141         ualg->cru_flags = alg->cra_flags;
 142         ualg->cru_refcnt = atomic_read(&alg->cra_refcnt);
 143
 144         if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
 145                 goto nla_put_failure;
 146         if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
 147                 struct crypto_report_larval rl;
 148
 149                 strncpy(rl.type, "larval", sizeof(rl.type));
 150                 if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL,
 151                             sizeof(struct crypto_report_larval), &rl))
 152                         goto nla_put_failure;
 153                 goto out;
 154         }
 155
 156         if (alg->cra_type && alg->cra_type->report) {
 157                 if (alg->cra_type->report(skb, alg))
 158                         goto nla_put_failure;
 159
 160                 goto out;
 161         }
 162
 163         switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
 164         case CRYPTO_ALG_TYPE_CIPHER:
 165                 if (crypto_report_cipher(skb, alg))
 166                         goto nla_put_failure;
 167
 168                 break;
 169         case CRYPTO_ALG_TYPE_COMPRESS:
 170                 if (crypto_report_comp(skb, alg))
 171                         goto nla_put_failure;
 172
 173                 break;
 174
 175         case CRYPTO_ALG_TYPE_AKCIPHER:
 176                 if (crypto_report_akcipher(skb, alg))
 177                         goto nla_put_failure;
 178
 179                 break;
 180         }
 181
 182 out:
 183         return 0;
 184
 185 nla_put_failure:
 186         return -EMSGSIZE;
 187 }
 188
 189 static int crypto_report_alg(struct crypto_alg *alg,
 190                              struct crypto_dump_info *info)
 191 {
 192         struct sk_buff *in_skb = info->in_skb;
 193         struct sk_buff *skb = info->out_skb;
 194         struct nlmsghdr *nlh;
 195         struct crypto_user_alg *ualg;
 196         int err = 0;
 197
 198         nlh = nlmsg_put(skb, NETLINK_CB(in_skb).portid, info->nlmsg_seq,
 199                         CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
 200         if (!nlh) {
 201                 err = -EMSGSIZE;
 202                 goto out;
 203         }
 204
 205         ualg = nlmsg_data(nlh);
 206
 207         err = crypto_report_one(alg, ualg, skb);
 208         if (err) {
 209                 nlmsg_cancel(skb, nlh);
 210                 goto out;
 211         }
 212
 213         nlmsg_end(skb, nlh);
 214
 215 out:
 216         return err;
 217 }
 218
 219 static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
 220                          struct nlattr **attrs)
 221 {
 222         struct crypto_user_alg *p = nlmsg_data(in_nlh);
 223         struct crypto_alg *alg;
 224         struct sk_buff *skb;
 225         struct crypto_dump_info info;
 226         int err;
 227
 228         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 229                 return -EINVAL;
 230
 231         alg = crypto_alg_match(p, 0);
 232         if (!alg)
 233                 return -ENOENT;
 234
 235         err = -ENOMEM;
 236         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
 237         if (!skb)
 238                 goto drop_alg;
 239
 240         info.in_skb = in_skb;
 241         info.out_skb = skb;
 242         info.nlmsg_seq = in_nlh->nlmsg_seq;
 243         info.nlmsg_flags = 0;
 244
 245         err = crypto_report_alg(alg, &info);
 246
 247 drop_alg:
 248         crypto_mod_put(alg);
 249
 250         if (err)
 251                 return err;
 252
 253         return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
 254 }
 255
 256 static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
 257 {
 258         struct crypto_alg *alg;
 259         struct crypto_dump_info info;
 260         int err;
 261
 262         if (cb->args[0])
 263                 goto out;
 264
 265         cb->args[0] = 1;
 266
 267         info.in_skb = cb->skb;
 268         info.out_skb = skb;
 269         info.nlmsg_seq = cb->nlh->nlmsg_seq;
 270         info.nlmsg_flags = NLM_F_MULTI;
 271
 272         list_for_each_entry(alg, &crypto_alg_list, cra_list) {
 273                 err = crypto_report_alg(alg, &info);
 274                 if (err)
 275                         goto out_err;
 276         }
 277
 278 out:
 279         return skb->len;
 280 out_err:
 281         return err;
 282 }
 283
 284 static int crypto_dump_report_done(struct netlink_callback *cb)
 285 {
 286         return 0;
 287 }
 288
 289 static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 290                              struct nlattr **attrs)
 291 {
 292         struct crypto_alg *alg;
 293         struct crypto_user_alg *p = nlmsg_data(nlh);
 294         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 295         LIST_HEAD(list);
 296
 297         if (!netlink_capable(skb, CAP_NET_ADMIN))
 298                 return -EPERM;
 299
 300         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 301                 return -EINVAL;
 302
 303         if (priority && !strlen(p->cru_driver_name))
 304                 return -EINVAL;
 305
 306         alg = crypto_alg_match(p, 1);
 307         if (!alg)
 308                 return -ENOENT;
 309
 310         down_write(&crypto_alg_sem);
 311
 312         crypto_remove_spawns(alg, &list, NULL);
 313
 314         if (priority)
 315                 alg->cra_priority = nla_get_u32(priority);
 316
 317         up_write(&crypto_alg_sem);
 318
 319         crypto_mod_put(alg);
 320         crypto_remove_final(&list);
 321
 322         return 0;
 323 }
 324
 325 static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 326                           struct nlattr **attrs)
 327 {
 328         struct crypto_alg *alg;
 329         struct crypto_user_alg *p = nlmsg_data(nlh);
 330         int err;
 331
 332         if (!netlink_capable(skb, CAP_NET_ADMIN))
 333                 return -EPERM;
 334
 335         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 336                 return -EINVAL;
 337
 338         alg = crypto_alg_match(p, 1);
 339         if (!alg)
 340                 return -ENOENT;
 341
 342         /* We can not unregister core algorithms such as aes-generic.
 343          * We would loose the reference in the crypto_alg_list to this algorithm
 344          * if we try to unregister. Unregistering such an algorithm without
 345          * removing the module is not possible, so we restrict to crypto
 346          * instances that are build from templates. */
 347         err = -EINVAL;
 348         if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
 349                 goto drop_alg;
 350
 351         err = -EBUSY;
 352         if (atomic_read(&alg->cra_refcnt) > 2)
 353                 goto drop_alg;
 354
 355         err = crypto_unregister_instance((struct crypto_instance *)alg);
 356
 357 drop_alg:
 358         crypto_mod_put(alg);
 359         return err;
 360 }
 361
 362 static struct crypto_alg *crypto_user_skcipher_alg(const char *name, u32 type,
 363                                                    u32 mask)
 364 {
 365         int err;
 366         struct crypto_alg *alg;
 367
 368         type = crypto_skcipher_type(type);
 369         mask = crypto_skcipher_mask(mask);
 370
 371         for (;;) {
 372                 alg = crypto_lookup_skcipher(name,  type, mask);
 373                 if (!IS_ERR(alg))
 374                         return alg;
 375
 376                 err = PTR_ERR(alg);
 377                 if (err != -EAGAIN)
 378                         break;
 379                 if (signal_pending(current)) {
 380                         err = -EINTR;
 381                         break;
 382                 }
 383         }
 384
 385         return ERR_PTR(err);
 386 }
 387
 388 static struct crypto_alg *crypto_user_aead_alg(const char *name, u32 type,
 389                                                u32 mask)
 390 {
 391         int err;
 392         struct crypto_alg *alg;
 393
 394         type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
 395         type |= CRYPTO_ALG_TYPE_AEAD;
 396         mask &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
 397         mask |= CRYPTO_ALG_TYPE_MASK;
 398
 399         for (;;) {
 400                 alg = crypto_lookup_aead(name,  type, mask);
 401                 if (!IS_ERR(alg))
 402                         return alg;
 403
 404                 err = PTR_ERR(alg);
 405                 if (err != -EAGAIN)
 406                         break;
 407                 if (signal_pending(current)) {
 408                         err = -EINTR;
 409                         break;
 410                 }
 411         }
 412
 413         return ERR_PTR(err);
 414 }
 415
 416 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 417                           struct nlattr **attrs)
 418 {
 419         int exact = 0;
 420         const char *name;
 421         struct crypto_alg *alg;
 422         struct crypto_user_alg *p = nlmsg_data(nlh);
 423         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 424
 425         if (!netlink_capable(skb, CAP_NET_ADMIN))
 426                 return -EPERM;
 427
 428         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 429                 return -EINVAL;
 430
 431         if (strlen(p->cru_driver_name))
 432                 exact = 1;
 433
 434         if (priority && !exact)
 435                 return -EINVAL;
 436
 437         alg = crypto_alg_match(p, exact);
 438         if (alg) {
 439                 crypto_mod_put(alg);
 440                 return -EEXIST;
 441         }
 442
 443         if (strlen(p->cru_driver_name))
 444                 name = p->cru_driver_name;
 445         else
 446                 name = p->cru_name;
 447
 448         switch (p->cru_type & p->cru_mask & CRYPTO_ALG_TYPE_MASK) {
 449         case CRYPTO_ALG_TYPE_AEAD:
 450                 alg = crypto_user_aead_alg(name, p->cru_type, p->cru_mask);
 451                 break;
 452         case CRYPTO_ALG_TYPE_GIVCIPHER:
 453         case CRYPTO_ALG_TYPE_BLKCIPHER:
 454         case CRYPTO_ALG_TYPE_ABLKCIPHER:
 455                 alg = crypto_user_skcipher_alg(name, p->cru_type, p->cru_mask);
 456                 break;
 457         default:
 458                 alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
 459         }
 460
 461         if (IS_ERR(alg))
 462                 return PTR_ERR(alg);
 463
 464         down_write(&crypto_alg_sem);
 465
 466         if (priority)
 467                 alg->cra_priority = nla_get_u32(priority);
 468
 469         up_write(&crypto_alg_sem);
 470
 471         crypto_mod_put(alg);
 472
 473         return 0;
 474 }
 475
 476 static int crypto_del_rng(struct sk_buff *skb, struct nlmsghdr *nlh,
 477                           struct nlattr **attrs)
 478 {
 479         if (!netlink_capable(skb, CAP_NET_ADMIN))
 480                 return -EPERM;
 481         return crypto_del_default_rng();
 482 }
 483
 484 #define MSGSIZE(type) sizeof(struct type)
 485
 486 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
 487         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 488         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 489         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 490         [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = 0,
 491 };
 492
 493 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
 494         [CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
 495 };
 496
 497 #undef MSGSIZE
 498
 499 static const struct crypto_link {
 500         int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
 501         int (*dump)(struct sk_buff *, struct netlink_callback *);
 502         int (*done)(struct netlink_callback *);
 503 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
 504         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
 505         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
 506         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
 507         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = { .doit = crypto_report,
 508                                                        .dump = crypto_dump_report,
 509                                                        .done = crypto_dump_report_done},
 510         [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_rng },
 511 };
 512
 513 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 514 {
 515         struct nlattr *attrs[CRYPTOCFGA_MAX+1];
 516         const struct crypto_link *link;
 517         int type, err;
 518
 519         type = nlh->nlmsg_type;
 520         if (type > CRYPTO_MSG_MAX)
 521                 return -EINVAL;
 522
 523         type -= CRYPTO_MSG_BASE;
 524         link = &crypto_dispatch[type];
 525
 526         if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
 527             (nlh->nlmsg_flags & NLM_F_DUMP))) {
 528                 struct crypto_alg *alg;
 529                 u16 dump_alloc = 0;
 530
 531                 if (link->dump == NULL)
 532                         return -EINVAL;
 533
 534                 list_for_each_entry(alg, &crypto_alg_list, cra_list)
 535                         dump_alloc += CRYPTO_REPORT_MAXSIZE;
 536
 537                 {
 538                         struct netlink_dump_control c = {
 539                                 .dump = link->dump,
 540                                 .done = link->done,
 541                                 .min_dump_alloc = dump_alloc,
 542                         };
 543                         return netlink_dump_start(crypto_nlsk, skb, nlh, &c);
 544                 }
 545         }
 546
 547         err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
 548                           crypto_policy);
 549         if (err < 0)
 550                 return err;
 551
 552         if (link->doit == NULL)
 553                 return -EINVAL;
 554
 555         return link->doit(skb, nlh, attrs);
 556 }
 557
 558 static void crypto_netlink_rcv(struct sk_buff *skb)
 559 {
 560         mutex_lock(&crypto_cfg_mutex);
 561         netlink_rcv_skb(skb, &crypto_user_rcv_msg);
 562         mutex_unlock(&crypto_cfg_mutex);
 563 }
 564
 565 static int __init crypto_user_init(void)
 566 {
 567         struct netlink_kernel_cfg cfg = {
 568                 .input  = crypto_netlink_rcv,
 569         };
 570
 571         crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO, &cfg);
 572         if (!crypto_nlsk)
 573                 return -ENOMEM;
 574
 575         return 0;
 576 }
 577
 578 static void __exit crypto_user_exit(void)
 579 {
 580         netlink_kernel_release(crypto_nlsk);
 581 }
 582
 583 module_init(crypto_user_init);
 584 module_exit(crypto_user_exit);
 585 MODULE_LICENSE("GPL");
 586 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 587 MODULE_DESCRIPTION("Crypto userspace configuration API");
 588 MODULE_ALIAS("net-pf-16-proto-21");