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