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