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