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/aead.h>
  29 #include <crypto/internal/skcipher.h>
  30
  31 #include "internal.h"
  32
  33 DEFINE_MUTEX(crypto_cfg_mutex);
  34
  35 /* The crypto netlink socket */
  36 static struct sock *crypto_nlsk;
  37
  38 struct crypto_dump_info {
  39         struct sk_buff *in_skb;
  40         struct sk_buff *out_skb;
  41         u32 nlmsg_seq;
  42         u16 nlmsg_flags;
  43 };
  44
  45 static struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
  46 {
  47         struct crypto_alg *q, *alg = NULL;
  48
  49         down_read(&crypto_alg_sem);
  50
  51         list_for_each_entry(q, &crypto_alg_list, cra_list) {
  52                 int match = 0;
  53
  54                 if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
  55                         continue;
  56
  57                 if (strlen(p->cru_driver_name))
  58                         match = !strcmp(q->cra_driver_name,
  59                                         p->cru_driver_name);
  60                 else if (!exact)
  61                         match = !strcmp(q->cra_name, p->cru_name);
  62
  63                 if (match) {
  64                         alg = q;
  65                         break;
  66                 }
  67         }
  68
  69         up_read(&crypto_alg_sem);
  70
  71         return alg;
  72 }
  73
  74 static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
  75 {
  76         struct crypto_report_cipher rcipher;
  77
  78         snprintf(rcipher.type, CRYPTO_MAX_ALG_NAME, "%s", "cipher");
  79
  80         rcipher.blocksize = alg->cra_blocksize;
  81         rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
  82         rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
  83
  84         if (nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
  85                     sizeof(struct crypto_report_cipher), &rcipher))
  86                 goto nla_put_failure;
  87         return 0;
  88
  89 nla_put_failure:
  90         return -EMSGSIZE;
  91 }
  92
  93 static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
  94 {
  95         struct crypto_report_comp rcomp;
  96
  97         snprintf(rcomp.type, CRYPTO_MAX_ALG_NAME, "%s", "compression");
  98
  99         if (nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS,
 100                     sizeof(struct crypto_report_comp), &rcomp))
 101                 goto nla_put_failure;
 102         return 0;
 103
 104 nla_put_failure:
 105         return -EMSGSIZE;
 106 }
 107
 108 static int crypto_report_one(struct crypto_alg *alg,
 109                              struct crypto_user_alg *ualg, struct sk_buff *skb)
 110 {
 111         memcpy(&ualg->cru_name, &alg->cra_name, sizeof(ualg->cru_name));
 112         memcpy(&ualg->cru_driver_name, &alg->cra_driver_name,
 113                sizeof(ualg->cru_driver_name));
 114         memcpy(&ualg->cru_module_name, module_name(alg->cra_module),
 115                CRYPTO_MAX_ALG_NAME);
 116
 117         ualg->cru_flags = alg->cra_flags;
 118         ualg->cru_refcnt = atomic_read(&alg->cra_refcnt);
 119
 120         if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
 121                 goto nla_put_failure;
 122         if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
 123                 struct crypto_report_larval rl;
 124
 125                 snprintf(rl.type, CRYPTO_MAX_ALG_NAME, "%s", "larval");
 126
 127                 if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL,
 128                             sizeof(struct crypto_report_larval), &rl))
 129                         goto nla_put_failure;
 130                 goto out;
 131         }
 132
 133         if (alg->cra_type && alg->cra_type->report) {
 134                 if (alg->cra_type->report(skb, alg))
 135                         goto nla_put_failure;
 136
 137                 goto out;
 138         }
 139
 140         switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
 141         case CRYPTO_ALG_TYPE_CIPHER:
 142                 if (crypto_report_cipher(skb, alg))
 143                         goto nla_put_failure;
 144
 145                 break;
 146         case CRYPTO_ALG_TYPE_COMPRESS:
 147                 if (crypto_report_comp(skb, alg))
 148                         goto nla_put_failure;
 149
 150                 break;
 151         }
 152
 153 out:
 154         return 0;
 155
 156 nla_put_failure:
 157         return -EMSGSIZE;
 158 }
 159
 160 static int crypto_report_alg(struct crypto_alg *alg,
 161                              struct crypto_dump_info *info)
 162 {
 163         struct sk_buff *in_skb = info->in_skb;
 164         struct sk_buff *skb = info->out_skb;
 165         struct nlmsghdr *nlh;
 166         struct crypto_user_alg *ualg;
 167         int err = 0;
 168
 169         nlh = nlmsg_put(skb, NETLINK_CB(in_skb).pid, info->nlmsg_seq,
 170                         CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
 171         if (!nlh) {
 172                 err = -EMSGSIZE;
 173                 goto out;
 174         }
 175
 176         ualg = nlmsg_data(nlh);
 177
 178         err = crypto_report_one(alg, ualg, skb);
 179         if (err) {
 180                 nlmsg_cancel(skb, nlh);
 181                 goto out;
 182         }
 183
 184         nlmsg_end(skb, nlh);
 185
 186 out:
 187         return err;
 188 }
 189
 190 static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
 191                          struct nlattr **attrs)
 192 {
 193         struct crypto_user_alg *p = nlmsg_data(in_nlh);
 194         struct crypto_alg *alg;
 195         struct sk_buff *skb;
 196         struct crypto_dump_info info;
 197         int err;
 198
 199         if (!p->cru_driver_name)
 200                 return -EINVAL;
 201
 202         alg = crypto_alg_match(p, 1);
 203         if (!alg)
 204                 return -ENOENT;
 205
 206         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
 207         if (!skb)
 208                 return -ENOMEM;
 209
 210         info.in_skb = in_skb;
 211         info.out_skb = skb;
 212         info.nlmsg_seq = in_nlh->nlmsg_seq;
 213         info.nlmsg_flags = 0;
 214
 215         err = crypto_report_alg(alg, &info);
 216         if (err)
 217                 return err;
 218
 219         return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).pid);
 220 }
 221
 222 static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
 223 {
 224         struct crypto_alg *alg;
 225         struct crypto_dump_info info;
 226         int err;
 227
 228         if (cb->args[0])
 229                 goto out;
 230
 231         cb->args[0] = 1;
 232
 233         info.in_skb = cb->skb;
 234         info.out_skb = skb;
 235         info.nlmsg_seq = cb->nlh->nlmsg_seq;
 236         info.nlmsg_flags = NLM_F_MULTI;
 237
 238         list_for_each_entry(alg, &crypto_alg_list, cra_list) {
 239                 err = crypto_report_alg(alg, &info);
 240                 if (err)
 241                         goto out_err;
 242         }
 243
 244 out:
 245         return skb->len;
 246 out_err:
 247         return err;
 248 }
 249
 250 static int crypto_dump_report_done(struct netlink_callback *cb)
 251 {
 252         return 0;
 253 }
 254
 255 static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 256                              struct nlattr **attrs)
 257 {
 258         struct crypto_alg *alg;
 259         struct crypto_user_alg *p = nlmsg_data(nlh);
 260         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 261         LIST_HEAD(list);
 262
 263         if (priority && !strlen(p->cru_driver_name))
 264                 return -EINVAL;
 265
 266         alg = crypto_alg_match(p, 1);
 267         if (!alg)
 268                 return -ENOENT;
 269
 270         down_write(&crypto_alg_sem);
 271
 272         crypto_remove_spawns(alg, &list, NULL);
 273
 274         if (priority)
 275                 alg->cra_priority = nla_get_u32(priority);
 276
 277         up_write(&crypto_alg_sem);
 278
 279         crypto_remove_final(&list);
 280
 281         return 0;
 282 }
 283
 284 static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 285                           struct nlattr **attrs)
 286 {
 287         struct crypto_alg *alg;
 288         struct crypto_user_alg *p = nlmsg_data(nlh);
 289
 290         alg = crypto_alg_match(p, 1);
 291         if (!alg)
 292                 return -ENOENT;
 293
 294         /* We can not unregister core algorithms such as aes-generic.
 295          * We would loose the reference in the crypto_alg_list to this algorithm
 296          * if we try to unregister. Unregistering such an algorithm without
 297          * removing the module is not possible, so we restrict to crypto
 298          * instances that are build from templates. */
 299         if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
 300                 return -EINVAL;
 301
 302         if (atomic_read(&alg->cra_refcnt) != 1)
 303                 return -EBUSY;
 304
 305         return crypto_unregister_instance(alg);
 306 }
 307
 308 static struct crypto_alg *crypto_user_skcipher_alg(const char *name, u32 type,
 309                                                    u32 mask)
 310 {
 311         int err;
 312         struct crypto_alg *alg;
 313
 314         type = crypto_skcipher_type(type);
 315         mask = crypto_skcipher_mask(mask);
 316
 317         for (;;) {
 318                 alg = crypto_lookup_skcipher(name,  type, mask);
 319                 if (!IS_ERR(alg))
 320                         return alg;
 321
 322                 err = PTR_ERR(alg);
 323                 if (err != -EAGAIN)
 324                         break;
 325                 if (signal_pending(current)) {
 326                         err = -EINTR;
 327                         break;
 328                 }
 329         }
 330
 331         return ERR_PTR(err);
 332 }
 333
 334 static struct crypto_alg *crypto_user_aead_alg(const char *name, u32 type,
 335                                                u32 mask)
 336 {
 337         int err;
 338         struct crypto_alg *alg;
 339
 340         type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
 341         type |= CRYPTO_ALG_TYPE_AEAD;
 342         mask &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
 343         mask |= CRYPTO_ALG_TYPE_MASK;
 344
 345         for (;;) {
 346                 alg = crypto_lookup_aead(name,  type, mask);
 347                 if (!IS_ERR(alg))
 348                         return alg;
 349
 350                 err = PTR_ERR(alg);
 351                 if (err != -EAGAIN)
 352                         break;
 353                 if (signal_pending(current)) {
 354                         err = -EINTR;
 355                         break;
 356                 }
 357         }
 358
 359         return ERR_PTR(err);
 360 }
 361
 362 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 363                           struct nlattr **attrs)
 364 {
 365         int exact = 0;
 366         const char *name;
 367         struct crypto_alg *alg;
 368         struct crypto_user_alg *p = nlmsg_data(nlh);
 369         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 370
 371         if (strlen(p->cru_driver_name))
 372                 exact = 1;
 373
 374         if (priority && !exact)
 375                 return -EINVAL;
 376
 377         alg = crypto_alg_match(p, exact);
 378         if (alg)
 379                 return -EEXIST;
 380
 381         if (strlen(p->cru_driver_name))
 382                 name = p->cru_driver_name;
 383         else
 384                 name = p->cru_name;
 385
 386         switch (p->cru_type & p->cru_mask & CRYPTO_ALG_TYPE_MASK) {
 387         case CRYPTO_ALG_TYPE_AEAD:
 388                 alg = crypto_user_aead_alg(name, p->cru_type, p->cru_mask);
 389                 break;
 390         case CRYPTO_ALG_TYPE_GIVCIPHER:
 391         case CRYPTO_ALG_TYPE_BLKCIPHER:
 392         case CRYPTO_ALG_TYPE_ABLKCIPHER:
 393                 alg = crypto_user_skcipher_alg(name, p->cru_type, p->cru_mask);
 394                 break;
 395         default:
 396                 alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
 397         }
 398
 399         if (IS_ERR(alg))
 400                 return PTR_ERR(alg);
 401
 402         down_write(&crypto_alg_sem);
 403
 404         if (priority)
 405                 alg->cra_priority = nla_get_u32(priority);
 406
 407         up_write(&crypto_alg_sem);
 408
 409         crypto_mod_put(alg);
 410
 411         return 0;
 412 }
 413
 414 #define MSGSIZE(type) sizeof(struct type)
 415
 416 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
 417         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 418         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 419         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 420         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 421 };
 422
 423 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
 424         [CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
 425 };
 426
 427 #undef MSGSIZE
 428
 429 static struct crypto_link {
 430         int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
 431         int (*dump)(struct sk_buff *, struct netlink_callback *);
 432         int (*done)(struct netlink_callback *);
 433 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
 434         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
 435         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
 436         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
 437         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = { .doit = crypto_report,
 438                                                        .dump = crypto_dump_report,
 439                                                        .done = crypto_dump_report_done},
 440 };
 441
 442 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 443 {
 444         struct nlattr *attrs[CRYPTOCFGA_MAX+1];
 445         struct crypto_link *link;
 446         int type, err;
 447
 448         type = nlh->nlmsg_type;
 449         if (type > CRYPTO_MSG_MAX)
 450                 return -EINVAL;
 451
 452         type -= CRYPTO_MSG_BASE;
 453         link = &crypto_dispatch[type];
 454
 455         if (!capable(CAP_NET_ADMIN))
 456                 return -EPERM;
 457
 458         if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
 459             (nlh->nlmsg_flags & NLM_F_DUMP))) {
 460                 struct crypto_alg *alg;
 461                 u16 dump_alloc = 0;
 462
 463                 if (link->dump == NULL)
 464                         return -EINVAL;
 465
 466                 list_for_each_entry(alg, &crypto_alg_list, cra_list)
 467                         dump_alloc += CRYPTO_REPORT_MAXSIZE;
 468
 469                 {
 470                         struct netlink_dump_control c = {
 471                                 .dump = link->dump,
 472                                 .done = link->done,
 473                                 .min_dump_alloc = dump_alloc,
 474                         };
 475                         return netlink_dump_start(crypto_nlsk, skb, nlh, &c);
 476                 }
 477         }
 478
 479         err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
 480                           crypto_policy);
 481         if (err < 0)
 482                 return err;
 483
 484         if (link->doit == NULL)
 485                 return -EINVAL;
 486
 487         return link->doit(skb, nlh, attrs);
 488 }
 489
 490 static void crypto_netlink_rcv(struct sk_buff *skb)
 491 {
 492         mutex_lock(&crypto_cfg_mutex);
 493         netlink_rcv_skb(skb, &crypto_user_rcv_msg);
 494         mutex_unlock(&crypto_cfg_mutex);
 495 }
 496
 497 static int __init crypto_user_init(void)
 498 {
 499         struct netlink_kernel_cfg cfg = {
 500                 .input  = crypto_netlink_rcv,
 501         };
 502
 503         crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO,
 504                                             THIS_MODULE, &cfg);
 505         if (!crypto_nlsk)
 506                 return -ENOMEM;
 507
 508         return 0;
 509 }
 510
 511 static void __exit crypto_user_exit(void)
 512 {
 513         netlink_kernel_release(crypto_nlsk);
 514 }
 515
 516 module_init(crypto_user_init);
 517 module_exit(crypto_user_exit);
 518 MODULE_LICENSE("GPL");
 519 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 520 MODULE_DESCRIPTION("Crypto userspace configuration API");