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