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