kernel/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 null_terminated(x)      (strnlen(x, sizeof(x)) < sizeof(x))
  34
  35 static DEFINE_MUTEX(crypto_cfg_mutex);
  36
  37 /* The crypto netlink socket */
  38 static struct sock *crypto_nlsk;
  39
  40 struct crypto_dump_info {
  41         struct sk_buff *in_skb;
  42         struct sk_buff *out_skb;
  43         u32 nlmsg_seq;
  44         u16 nlmsg_flags;
  45 };
  46
  47 static struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
  48 {
  49         struct crypto_alg *q, *alg = NULL;
  50
  51         down_read(&crypto_alg_sem);
  52
  53         list_for_each_entry(q, &crypto_alg_list, cra_list) {
  54                 int match = 0;
  55
  56                 if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
  57                         continue;
  58
  59                 if (strlen(p->cru_driver_name))
  60                         match = !strcmp(q->cra_driver_name,
  61                                         p->cru_driver_name);
  62                 else if (!exact)
  63                         match = !strcmp(q->cra_name, p->cru_name);
  64
  65                 if (!match)
  66                         continue;
  67
  68                 if (unlikely(!crypto_mod_get(q)))
  69                         continue;
  70
  71                 alg = q;
  72                 break;
  73         }
  74
  75         up_read(&crypto_alg_sem);
  76
  77         return alg;
  78 }
  79
  80 static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
  81 {
  82         struct crypto_report_cipher rcipher;
  83
  84         strncpy(rcipher.type, "cipher", sizeof(rcipher.type));
  85
  86         rcipher.blocksize = alg->cra_blocksize;
  87         rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
  88         rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
  89
  90         if (nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
  91                     sizeof(struct crypto_report_cipher), &rcipher))
  92                 goto nla_put_failure;
  93         return 0;
  94
  95 nla_put_failure:
  96         return -EMSGSIZE;
  97 }
  98
  99 static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
 100 {
 101         struct crypto_report_comp rcomp;
 102
 103         strncpy(rcomp.type, "compression", sizeof(rcomp.type));
 104         if (nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS,
 105                     sizeof(struct crypto_report_comp), &rcomp))
 106                 goto nla_put_failure;
 107         return 0;
 108
 109 nla_put_failure:
 110         return -EMSGSIZE;
 111 }
 112
 113 static int crypto_report_one(struct crypto_alg *alg,
 114                              struct crypto_user_alg *ualg, struct sk_buff *skb)
 115 {
 116         strncpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
 117         strncpy(ualg->cru_driver_name, alg->cra_driver_name,
 118                 sizeof(ualg->cru_driver_name));
 119         strncpy(ualg->cru_module_name, module_name(alg->cra_module),
 120                 sizeof(ualg->cru_module_name));
 121
 122         ualg->cru_type = 0;
 123         ualg->cru_mask = 0;
 124         ualg->cru_flags = alg->cra_flags;
 125         ualg->cru_refcnt = atomic_read(&alg->cra_refcnt);
 126
 127         if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
 128                 goto nla_put_failure;
 129         if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
 130                 struct crypto_report_larval rl;
 131
 132                 strncpy(rl.type, "larval", sizeof(rl.type));
 133                 if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL,
 134                             sizeof(struct crypto_report_larval), &rl))
 135                         goto nla_put_failure;
 136                 goto out;
 137         }
 138
 139         if (alg->cra_type && alg->cra_type->report) {
 140                 if (alg->cra_type->report(skb, alg))
 141                         goto nla_put_failure;
 142
 143                 goto out;
 144         }
 145
 146         switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
 147         case CRYPTO_ALG_TYPE_CIPHER:
 148                 if (crypto_report_cipher(skb, alg))
 149                         goto nla_put_failure;
 150
 151                 break;
 152         case CRYPTO_ALG_TYPE_COMPRESS:
 153                 if (crypto_report_comp(skb, alg))
 154                         goto nla_put_failure;
 155
 156                 break;
 157         }
 158
 159 out:
 160         return 0;
 161
 162 nla_put_failure:
 163         return -EMSGSIZE;
 164 }
 165
 166 static int crypto_report_alg(struct crypto_alg *alg,
 167                              struct crypto_dump_info *info)
 168 {
 169         struct sk_buff *in_skb = info->in_skb;
 170         struct sk_buff *skb = info->out_skb;
 171         struct nlmsghdr *nlh;
 172         struct crypto_user_alg *ualg;
 173         int err = 0;
 174
 175         nlh = nlmsg_put(skb, NETLINK_CB(in_skb).portid, info->nlmsg_seq,
 176                         CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
 177         if (!nlh) {
 178                 err = -EMSGSIZE;
 179                 goto out;
 180         }
 181
 182         ualg = nlmsg_data(nlh);
 183
 184         err = crypto_report_one(alg, ualg, skb);
 185         if (err) {
 186                 nlmsg_cancel(skb, nlh);
 187                 goto out;
 188         }
 189
 190         nlmsg_end(skb, nlh);
 191
 192 out:
 193         return err;
 194 }
 195
 196 static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
 197                          struct nlattr **attrs)
 198 {
 199         struct crypto_user_alg *p = nlmsg_data(in_nlh);
 200         struct crypto_alg *alg;
 201         struct sk_buff *skb;
 202         struct crypto_dump_info info;
 203         int err;
 204
 205         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 206                 return -EINVAL;
 207
 208         alg = crypto_alg_match(p, 0);
 209         if (!alg)
 210                 return -ENOENT;
 211
 212         err = -ENOMEM;
 213         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
 214         if (!skb)
 215                 goto drop_alg;
 216
 217         info.in_skb = in_skb;
 218         info.out_skb = skb;
 219         info.nlmsg_seq = in_nlh->nlmsg_seq;
 220         info.nlmsg_flags = 0;
 221
 222         err = crypto_report_alg(alg, &info);
 223
 224 drop_alg:
 225         crypto_mod_put(alg);
 226
 227         if (err)
 228                 return err;
 229
 230         return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
 231 }
 232
 233 static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
 234 {
 235         struct crypto_alg *alg;
 236         struct crypto_dump_info info;
 237         int err;
 238
 239         if (cb->args[0])
 240                 goto out;
 241
 242         cb->args[0] = 1;
 243
 244         info.in_skb = cb->skb;
 245         info.out_skb = skb;
 246         info.nlmsg_seq = cb->nlh->nlmsg_seq;
 247         info.nlmsg_flags = NLM_F_MULTI;
 248
 249         list_for_each_entry(alg, &crypto_alg_list, cra_list) {
 250                 err = crypto_report_alg(alg, &info);
 251                 if (err)
 252                         goto out_err;
 253         }
 254
 255 out:
 256         return skb->len;
 257 out_err:
 258         return err;
 259 }
 260
 261 static int crypto_dump_report_done(struct netlink_callback *cb)
 262 {
 263         return 0;
 264 }
 265
 266 static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 267                              struct nlattr **attrs)
 268 {
 269         struct crypto_alg *alg;
 270         struct crypto_user_alg *p = nlmsg_data(nlh);
 271         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 272         LIST_HEAD(list);
 273
 274         if (!netlink_capable(skb, CAP_NET_ADMIN))
 275                 return -EPERM;
 276
 277         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 278                 return -EINVAL;
 279
 280         if (priority && !strlen(p->cru_driver_name))
 281                 return -EINVAL;
 282
 283         alg = crypto_alg_match(p, 1);
 284         if (!alg)
 285                 return -ENOENT;
 286
 287         down_write(&crypto_alg_sem);
 288
 289         crypto_remove_spawns(alg, &list, NULL);
 290
 291         if (priority)
 292                 alg->cra_priority = nla_get_u32(priority);
 293
 294         up_write(&crypto_alg_sem);
 295
 296         crypto_mod_put(alg);
 297         crypto_remove_final(&list);
 298
 299         return 0;
 300 }
 301
 302 static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 303                           struct nlattr **attrs)
 304 {
 305         struct crypto_alg *alg;
 306         struct crypto_user_alg *p = nlmsg_data(nlh);
 307         int err;
 308
 309         if (!netlink_capable(skb, CAP_NET_ADMIN))
 310                 return -EPERM;
 311
 312         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 313                 return -EINVAL;
 314
 315         alg = crypto_alg_match(p, 1);
 316         if (!alg)
 317                 return -ENOENT;
 318
 319         /* We can not unregister core algorithms such as aes-generic.
 320          * We would loose the reference in the crypto_alg_list to this algorithm
 321          * if we try to unregister. Unregistering such an algorithm without
 322          * removing the module is not possible, so we restrict to crypto
 323          * instances that are build from templates. */
 324         err = -EINVAL;
 325         if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
 326                 goto drop_alg;
 327
 328         err = -EBUSY;
 329         if (atomic_read(&alg->cra_refcnt) > 2)
 330                 goto drop_alg;
 331
 332         err = crypto_unregister_instance((struct crypto_instance *)alg);
 333
 334 drop_alg:
 335         crypto_mod_put(alg);
 336         return err;
 337 }
 338
 339 static struct crypto_alg *crypto_user_skcipher_alg(const char *name, u32 type,
 340                                                    u32 mask)
 341 {
 342         int err;
 343         struct crypto_alg *alg;
 344
 345         type = crypto_skcipher_type(type);
 346         mask = crypto_skcipher_mask(mask);
 347
 348         for (;;) {
 349                 alg = crypto_lookup_skcipher(name,  type, mask);
 350                 if (!IS_ERR(alg))
 351                         return alg;
 352
 353                 err = PTR_ERR(alg);
 354                 if (err != -EAGAIN)
 355                         break;
 356                 if (signal_pending(current)) {
 357                         err = -EINTR;
 358                         break;
 359                 }
 360         }
 361
 362         return ERR_PTR(err);
 363 }
 364
 365 static struct crypto_alg *crypto_user_aead_alg(const char *name, u32 type,
 366                                                u32 mask)
 367 {
 368         int err;
 369         struct crypto_alg *alg;
 370
 371         type &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
 372         type |= CRYPTO_ALG_TYPE_AEAD;
 373         mask &= ~(CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_GENIV);
 374         mask |= CRYPTO_ALG_TYPE_MASK;
 375
 376         for (;;) {
 377                 alg = crypto_lookup_aead(name,  type, mask);
 378                 if (!IS_ERR(alg))
 379                         return alg;
 380
 381                 err = PTR_ERR(alg);
 382                 if (err != -EAGAIN)
 383                         break;
 384                 if (signal_pending(current)) {
 385                         err = -EINTR;
 386                         break;
 387                 }
 388         }
 389
 390         return ERR_PTR(err);
 391 }
 392
 393 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 394                           struct nlattr **attrs)
 395 {
 396         int exact = 0;
 397         const char *name;
 398         struct crypto_alg *alg;
 399         struct crypto_user_alg *p = nlmsg_data(nlh);
 400         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 401
 402         if (!netlink_capable(skb, CAP_NET_ADMIN))
 403                 return -EPERM;
 404
 405         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 406                 return -EINVAL;
 407
 408         if (strlen(p->cru_driver_name))
 409                 exact = 1;
 410
 411         if (priority && !exact)
 412                 return -EINVAL;
 413
 414         alg = crypto_alg_match(p, exact);
 415         if (alg) {
 416                 crypto_mod_put(alg);
 417                 return -EEXIST;
 418         }
 419
 420         if (strlen(p->cru_driver_name))
 421                 name = p->cru_driver_name;
 422         else
 423                 name = p->cru_name;
 424
 425         switch (p->cru_type & p->cru_mask & CRYPTO_ALG_TYPE_MASK) {
 426         case CRYPTO_ALG_TYPE_AEAD:
 427                 alg = crypto_user_aead_alg(name, p->cru_type, p->cru_mask);
 428                 break;
 429         case CRYPTO_ALG_TYPE_GIVCIPHER:
 430         case CRYPTO_ALG_TYPE_BLKCIPHER:
 431         case CRYPTO_ALG_TYPE_ABLKCIPHER:
 432                 alg = crypto_user_skcipher_alg(name, p->cru_type, p->cru_mask);
 433                 break;
 434         default:
 435                 alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
 436         }
 437
 438         if (IS_ERR(alg))
 439                 return PTR_ERR(alg);
 440
 441         down_write(&crypto_alg_sem);
 442
 443         if (priority)
 444                 alg->cra_priority = nla_get_u32(priority);
 445
 446         up_write(&crypto_alg_sem);
 447
 448         crypto_mod_put(alg);
 449
 450         return 0;
 451 }
 452
 453 #define MSGSIZE(type) sizeof(struct type)
 454
 455 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
 456         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 457         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 458         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 459         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 460 };
 461
 462 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
 463         [CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
 464 };
 465
 466 #undef MSGSIZE
 467
 468 static const struct crypto_link {
 469         int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
 470         int (*dump)(struct sk_buff *, struct netlink_callback *);
 471         int (*done)(struct netlink_callback *);
 472 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
 473         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
 474         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
 475         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
 476         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = { .doit = crypto_report,
 477                                                        .dump = crypto_dump_report,
 478                                                        .done = crypto_dump_report_done},
 479 };
 480
 481 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 482 {
 483         struct nlattr *attrs[CRYPTOCFGA_MAX+1];
 484         const struct crypto_link *link;
 485         int type, err;
 486
 487         type = nlh->nlmsg_type;
 488         if (type > CRYPTO_MSG_MAX)
 489                 return -EINVAL;
 490
 491         type -= CRYPTO_MSG_BASE;
 492         link = &crypto_dispatch[type];
 493
 494         if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
 495             (nlh->nlmsg_flags & NLM_F_DUMP))) {
 496                 struct crypto_alg *alg;
 497                 u16 dump_alloc = 0;
 498
 499                 if (link->dump == NULL)
 500                         return -EINVAL;
 501
 502                 list_for_each_entry(alg, &crypto_alg_list, cra_list)
 503                         dump_alloc += CRYPTO_REPORT_MAXSIZE;
 504
 505                 {
 506                         struct netlink_dump_control c = {
 507                                 .dump = link->dump,
 508                                 .done = link->done,
 509                                 .min_dump_alloc = dump_alloc,
 510                         };
 511                         return netlink_dump_start(crypto_nlsk, skb, nlh, &c);
 512                 }
 513         }
 514
 515         err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
 516                           crypto_policy);
 517         if (err < 0)
 518                 return err;
 519
 520         if (link->doit == NULL)
 521                 return -EINVAL;
 522
 523         return link->doit(skb, nlh, attrs);
 524 }
 525
 526 static void crypto_netlink_rcv(struct sk_buff *skb)
 527 {
 528         mutex_lock(&crypto_cfg_mutex);
 529         netlink_rcv_skb(skb, &crypto_user_rcv_msg);
 530         mutex_unlock(&crypto_cfg_mutex);
 531 }
 532
 533 static int __init crypto_user_init(void)
 534 {
 535         struct netlink_kernel_cfg cfg = {
 536                 .input  = crypto_netlink_rcv,
 537         };
 538
 539         crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO, &cfg);
 540         if (!crypto_nlsk)
 541                 return -ENOMEM;
 542
 543         return 0;
 544 }
 545
 546 static void __exit crypto_user_exit(void)
 547 {
 548         netlink_kernel_release(crypto_nlsk);
 549 }
 550
 551 module_init(crypto_user_init);
 552 module_exit(crypto_user_exit);
 553 MODULE_LICENSE("GPL");
 554 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 555 MODULE_DESCRIPTION("Crypto userspace configuration API");
 556 MODULE_ALIAS("net-pf-16-proto-21");