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/skcipher.h>
  29 #include <crypto/internal/rng.h>
  30 #include <crypto/akcipher.h>
  31
  32 #include "internal.h"
  33
  34 #define null_terminated(x)      (strnlen(x, sizeof(x)) < sizeof(x))
  35
  36 static DEFINE_MUTEX(crypto_cfg_mutex);
  37
  38 /* The crypto netlink socket */
  39 static struct sock *crypto_nlsk;
  40
  41 struct crypto_dump_info {
  42         struct sk_buff *in_skb;
  43         struct sk_buff *out_skb;
  44         u32 nlmsg_seq;
  45         u16 nlmsg_flags;
  46 };
  47
  48 static struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
  49 {
  50         struct crypto_alg *q, *alg = NULL;
  51
  52         down_read(&crypto_alg_sem);
  53
  54         list_for_each_entry(q, &crypto_alg_list, cra_list) {
  55                 int match = 0;
  56
  57                 if (crypto_is_larval(q))
  58                         continue;
  59
  60                 if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
  61                         continue;
  62
  63                 if (strlen(p->cru_driver_name))
  64                         match = !strcmp(q->cra_driver_name,
  65                                         p->cru_driver_name);
  66                 else if (!exact)
  67                         match = !strcmp(q->cra_name, p->cru_name);
  68
  69                 if (!match)
  70                         continue;
  71
  72                 if (unlikely(!crypto_mod_get(q)))
  73                         continue;
  74
  75                 alg = q;
  76                 break;
  77         }
  78
  79         up_read(&crypto_alg_sem);
  80
  81         return alg;
  82 }
  83
  84 static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
  85 {
  86         struct crypto_report_cipher rcipher;
  87
  88         strncpy(rcipher.type, "cipher", sizeof(rcipher.type));
  89
  90         rcipher.blocksize = alg->cra_blocksize;
  91         rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
  92         rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
  93
  94         if (nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
  95                     sizeof(struct crypto_report_cipher), &rcipher))
  96                 goto nla_put_failure;
  97         return 0;
  98
  99 nla_put_failure:
 100         return -EMSGSIZE;
 101 }
 102
 103 static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
 104 {
 105         struct crypto_report_comp rcomp;
 106
 107         strncpy(rcomp.type, "compression", sizeof(rcomp.type));
 108         if (nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS,
 109                     sizeof(struct crypto_report_comp), &rcomp))
 110                 goto nla_put_failure;
 111         return 0;
 112
 113 nla_put_failure:
 114         return -EMSGSIZE;
 115 }
 116
 117 static int crypto_report_akcipher(struct sk_buff *skb, struct crypto_alg *alg)
 118 {
 119         struct crypto_report_akcipher rakcipher;
 120
 121         strncpy(rakcipher.type, "akcipher", sizeof(rakcipher.type));
 122
 123         if (nla_put(skb, CRYPTOCFGA_REPORT_AKCIPHER,
 124                     sizeof(struct crypto_report_akcipher), &rakcipher))
 125                 goto nla_put_failure;
 126         return 0;
 127
 128 nla_put_failure:
 129         return -EMSGSIZE;
 130 }
 131
 132 static int crypto_report_one(struct crypto_alg *alg,
 133                              struct crypto_user_alg *ualg, struct sk_buff *skb)
 134 {
 135         strncpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
 136         strncpy(ualg->cru_driver_name, alg->cra_driver_name,
 137                 sizeof(ualg->cru_driver_name));
 138         strncpy(ualg->cru_module_name, module_name(alg->cra_module),
 139                 sizeof(ualg->cru_module_name));
 140
 141         ualg->cru_type = 0;
 142         ualg->cru_mask = 0;
 143         ualg->cru_flags = alg->cra_flags;
 144         ualg->cru_refcnt = atomic_read(&alg->cra_refcnt);
 145
 146         if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
 147                 goto nla_put_failure;
 148         if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
 149                 struct crypto_report_larval rl;
 150
 151                 strncpy(rl.type, "larval", sizeof(rl.type));
 152                 if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL,
 153                             sizeof(struct crypto_report_larval), &rl))
 154                         goto nla_put_failure;
 155                 goto out;
 156         }
 157
 158         if (alg->cra_type && alg->cra_type->report) {
 159                 if (alg->cra_type->report(skb, alg))
 160                         goto nla_put_failure;
 161
 162                 goto out;
 163         }
 164
 165         switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
 166         case CRYPTO_ALG_TYPE_CIPHER:
 167                 if (crypto_report_cipher(skb, alg))
 168                         goto nla_put_failure;
 169
 170                 break;
 171         case CRYPTO_ALG_TYPE_COMPRESS:
 172                 if (crypto_report_comp(skb, alg))
 173                         goto nla_put_failure;
 174
 175                 break;
 176
 177         case CRYPTO_ALG_TYPE_AKCIPHER:
 178                 if (crypto_report_akcipher(skb, alg))
 179                         goto nla_put_failure;
 180
 181                 break;
 182         }
 183
 184 out:
 185         return 0;
 186
 187 nla_put_failure:
 188         return -EMSGSIZE;
 189 }
 190
 191 static int crypto_report_alg(struct crypto_alg *alg,
 192                              struct crypto_dump_info *info)
 193 {
 194         struct sk_buff *in_skb = info->in_skb;
 195         struct sk_buff *skb = info->out_skb;
 196         struct nlmsghdr *nlh;
 197         struct crypto_user_alg *ualg;
 198         int err = 0;
 199
 200         nlh = nlmsg_put(skb, NETLINK_CB(in_skb).portid, info->nlmsg_seq,
 201                         CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
 202         if (!nlh) {
 203                 err = -EMSGSIZE;
 204                 goto out;
 205         }
 206
 207         ualg = nlmsg_data(nlh);
 208
 209         err = crypto_report_one(alg, ualg, skb);
 210         if (err) {
 211                 nlmsg_cancel(skb, nlh);
 212                 goto out;
 213         }
 214
 215         nlmsg_end(skb, nlh);
 216
 217 out:
 218         return err;
 219 }
 220
 221 static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
 222                          struct nlattr **attrs)
 223 {
 224         struct crypto_user_alg *p = nlmsg_data(in_nlh);
 225         struct crypto_alg *alg;
 226         struct sk_buff *skb;
 227         struct crypto_dump_info info;
 228         int err;
 229
 230         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 231                 return -EINVAL;
 232
 233         alg = crypto_alg_match(p, 0);
 234         if (!alg)
 235                 return -ENOENT;
 236
 237         err = -ENOMEM;
 238         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
 239         if (!skb)
 240                 goto drop_alg;
 241
 242         info.in_skb = in_skb;
 243         info.out_skb = skb;
 244         info.nlmsg_seq = in_nlh->nlmsg_seq;
 245         info.nlmsg_flags = 0;
 246
 247         err = crypto_report_alg(alg, &info);
 248
 249 drop_alg:
 250         crypto_mod_put(alg);
 251
 252         if (err) {
 253                 kfree_skb(skb);
 254                 return err;
 255         }
 256
 257         return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
 258 }
 259
 260 static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
 261 {
 262         const size_t start_pos = cb->args[0];
 263         size_t pos = 0;
 264         struct crypto_dump_info info;
 265         struct crypto_alg *alg;
 266         int res;
 267
 268         info.in_skb = cb->skb;
 269         info.out_skb = skb;
 270         info.nlmsg_seq = cb->nlh->nlmsg_seq;
 271         info.nlmsg_flags = NLM_F_MULTI;
 272
 273         down_read(&crypto_alg_sem);
 274         list_for_each_entry(alg, &crypto_alg_list, cra_list) {
 275                 if (pos >= start_pos) {
 276                         res = crypto_report_alg(alg, &info);
 277                         if (res == -EMSGSIZE)
 278                                 break;
 279                         if (res)
 280                                 goto out;
 281                 }
 282                 pos++;
 283         }
 284         cb->args[0] = pos;
 285         res = skb->len;
 286 out:
 287         up_read(&crypto_alg_sem);
 288         return res;
 289 }
 290
 291 static int crypto_dump_report_done(struct netlink_callback *cb)
 292 {
 293         return 0;
 294 }
 295
 296 static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 297                              struct nlattr **attrs)
 298 {
 299         struct crypto_alg *alg;
 300         struct crypto_user_alg *p = nlmsg_data(nlh);
 301         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 302         LIST_HEAD(list);
 303
 304         if (!netlink_capable(skb, CAP_NET_ADMIN))
 305                 return -EPERM;
 306
 307         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 308                 return -EINVAL;
 309
 310         if (priority && !strlen(p->cru_driver_name))
 311                 return -EINVAL;
 312
 313         alg = crypto_alg_match(p, 1);
 314         if (!alg)
 315                 return -ENOENT;
 316
 317         down_write(&crypto_alg_sem);
 318
 319         crypto_remove_spawns(alg, &list, NULL);
 320
 321         if (priority)
 322                 alg->cra_priority = nla_get_u32(priority);
 323
 324         up_write(&crypto_alg_sem);
 325
 326         crypto_mod_put(alg);
 327         crypto_remove_final(&list);
 328
 329         return 0;
 330 }
 331
 332 static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 333                           struct nlattr **attrs)
 334 {
 335         struct crypto_alg *alg;
 336         struct crypto_user_alg *p = nlmsg_data(nlh);
 337         int err;
 338
 339         if (!netlink_capable(skb, CAP_NET_ADMIN))
 340                 return -EPERM;
 341
 342         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 343                 return -EINVAL;
 344
 345         alg = crypto_alg_match(p, 1);
 346         if (!alg)
 347                 return -ENOENT;
 348
 349         /* We can not unregister core algorithms such as aes-generic.
 350          * We would loose the reference in the crypto_alg_list to this algorithm
 351          * if we try to unregister. Unregistering such an algorithm without
 352          * removing the module is not possible, so we restrict to crypto
 353          * instances that are build from templates. */
 354         err = -EINVAL;
 355         if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
 356                 goto drop_alg;
 357
 358         err = -EBUSY;
 359         if (atomic_read(&alg->cra_refcnt) > 2)
 360                 goto drop_alg;
 361
 362         err = crypto_unregister_instance((struct crypto_instance *)alg);
 363
 364 drop_alg:
 365         crypto_mod_put(alg);
 366         return err;
 367 }
 368
 369 static struct crypto_alg *crypto_user_skcipher_alg(const char *name, u32 type,
 370                                                    u32 mask)
 371 {
 372         int err;
 373         struct crypto_alg *alg;
 374
 375         type = crypto_skcipher_type(type);
 376         mask = crypto_skcipher_mask(mask);
 377
 378         for (;;) {
 379                 alg = crypto_lookup_skcipher(name,  type, mask);
 380                 if (!IS_ERR(alg))
 381                         return alg;
 382
 383                 err = PTR_ERR(alg);
 384                 if (err != -EAGAIN)
 385                         break;
 386                 if (fatal_signal_pending(current)) {
 387                         err = -EINTR;
 388                         break;
 389                 }
 390         }
 391
 392         return ERR_PTR(err);
 393 }
 394
 395 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 396                           struct nlattr **attrs)
 397 {
 398         int exact = 0;
 399         const char *name;
 400         struct crypto_alg *alg;
 401         struct crypto_user_alg *p = nlmsg_data(nlh);
 402         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 403
 404         if (!netlink_capable(skb, CAP_NET_ADMIN))
 405                 return -EPERM;
 406
 407         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 408                 return -EINVAL;
 409
 410         if (strlen(p->cru_driver_name))
 411                 exact = 1;
 412
 413         if (priority && !exact)
 414                 return -EINVAL;
 415
 416         alg = crypto_alg_match(p, exact);
 417         if (alg) {
 418                 crypto_mod_put(alg);
 419                 return -EEXIST;
 420         }
 421
 422         if (strlen(p->cru_driver_name))
 423                 name = p->cru_driver_name;
 424         else
 425                 name = p->cru_name;
 426
 427         switch (p->cru_type & p->cru_mask & CRYPTO_ALG_TYPE_MASK) {
 428         case CRYPTO_ALG_TYPE_GIVCIPHER:
 429         case CRYPTO_ALG_TYPE_BLKCIPHER:
 430         case CRYPTO_ALG_TYPE_ABLKCIPHER:
 431                 alg = crypto_user_skcipher_alg(name, p->cru_type, p->cru_mask);
 432                 break;
 433         default:
 434                 alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
 435         }
 436
 437         if (IS_ERR(alg))
 438                 return PTR_ERR(alg);
 439
 440         down_write(&crypto_alg_sem);
 441
 442         if (priority)
 443                 alg->cra_priority = nla_get_u32(priority);
 444
 445         up_write(&crypto_alg_sem);
 446
 447         crypto_mod_put(alg);
 448
 449         return 0;
 450 }
 451
 452 static int crypto_del_rng(struct sk_buff *skb, struct nlmsghdr *nlh,
 453                           struct nlattr **attrs)
 454 {
 455         if (!netlink_capable(skb, CAP_NET_ADMIN))
 456                 return -EPERM;
 457         return crypto_del_default_rng();
 458 }
 459
 460 #define MSGSIZE(type) sizeof(struct type)
 461
 462 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
 463         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 464         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 465         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 466         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 467         [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = 0,
 468 };
 469
 470 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
 471         [CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
 472 };
 473
 474 #undef MSGSIZE
 475
 476 static const struct crypto_link {
 477         int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
 478         int (*dump)(struct sk_buff *, struct netlink_callback *);
 479         int (*done)(struct netlink_callback *);
 480 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
 481         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
 482         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
 483         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
 484         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = { .doit = crypto_report,
 485                                                        .dump = crypto_dump_report,
 486                                                        .done = crypto_dump_report_done},
 487         [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_rng },
 488 };
 489
 490 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 491 {
 492         struct nlattr *attrs[CRYPTOCFGA_MAX+1];
 493         const struct crypto_link *link;
 494         int type, err;
 495
 496         type = nlh->nlmsg_type;
 497         if (type > CRYPTO_MSG_MAX)
 498                 return -EINVAL;
 499
 500         type -= CRYPTO_MSG_BASE;
 501         link = &crypto_dispatch[type];
 502
 503         if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
 504             (nlh->nlmsg_flags & NLM_F_DUMP))) {
 505                 struct crypto_alg *alg;
 506                 unsigned long dump_alloc = 0;
 507
 508                 if (link->dump == NULL)
 509                         return -EINVAL;
 510
 511                 down_read(&crypto_alg_sem);
 512                 list_for_each_entry(alg, &crypto_alg_list, cra_list)
 513                         dump_alloc += CRYPTO_REPORT_MAXSIZE;
 514                 up_read(&crypto_alg_sem);
 515
 516                 {
 517                         struct netlink_dump_control c = {
 518                                 .dump = link->dump,
 519                                 .done = link->done,
 520                                 .min_dump_alloc = min(dump_alloc, 65535UL),
 521                         };
 522                         err = netlink_dump_start(crypto_nlsk, skb, nlh, &c);
 523                 }
 524
 525                 return err;
 526         }
 527
 528         err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
 529                           crypto_policy);
 530         if (err < 0)
 531                 return err;
 532
 533         if (link->doit == NULL)
 534                 return -EINVAL;
 535
 536         return link->doit(skb, nlh, attrs);
 537 }
 538
 539 static void crypto_netlink_rcv(struct sk_buff *skb)
 540 {
 541         mutex_lock(&crypto_cfg_mutex);
 542         netlink_rcv_skb(skb, &crypto_user_rcv_msg);
 543         mutex_unlock(&crypto_cfg_mutex);
 544 }
 545
 546 static int __init crypto_user_init(void)
 547 {
 548         struct netlink_kernel_cfg cfg = {
 549                 .input  = crypto_netlink_rcv,
 550         };
 551
 552         crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO, &cfg);
 553         if (!crypto_nlsk)
 554                 return -ENOMEM;
 555
 556         return 0;
 557 }
 558
 559 static void __exit crypto_user_exit(void)
 560 {
 561         netlink_kernel_release(crypto_nlsk);
 562 }
 563
 564 module_init(crypto_user_init);
 565 module_exit(crypto_user_exit);
 566 MODULE_LICENSE("GPL");
 567 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 568 MODULE_DESCRIPTION("Crypto userspace configuration API");
 569 MODULE_ALIAS("net-pf-16-proto-21");