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