crypto/crypto_user_base.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 #include <crypto/internal/cryptouser.h>
  33
  34 #include "internal.h"
  35
  36 #define null_terminated(x)      (strnlen(x, sizeof(x)) < sizeof(x))
  37
  38 static DEFINE_MUTEX(crypto_cfg_mutex);
  39
  40 /* The crypto netlink socket */
  41 struct sock *crypto_nlsk;
  42
  43 struct crypto_dump_info {
  44         struct sk_buff *in_skb;
  45         struct sk_buff *out_skb;
  46         u32 nlmsg_seq;
  47         u16 nlmsg_flags;
  48 };
  49
  50 struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
  51 {
  52         struct crypto_alg *q, *alg = NULL;
  53
  54         down_read(&crypto_alg_sem);
  55
  56         list_for_each_entry(q, &crypto_alg_list, cra_list) {
  57                 int match = 0;
  58
  59                 if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
  60                         continue;
  61
  62                 if (strlen(p->cru_driver_name))
  63                         match = !strcmp(q->cra_driver_name,
  64                                         p->cru_driver_name);
  65                 else if (!exact)
  66                         match = !strcmp(q->cra_name, p->cru_name);
  67
  68                 if (!match)
  69                         continue;
  70
  71                 if (unlikely(!crypto_mod_get(q)))
  72                         continue;
  73
  74                 alg = q;
  75                 break;
  76         }
  77
  78         up_read(&crypto_alg_sem);
  79
  80         return alg;
  81 }
  82
  83 static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
  84 {
  85         struct crypto_report_cipher rcipher;
  86
  87         strncpy(rcipher.type, "cipher", sizeof(rcipher.type));
  88
  89         rcipher.blocksize = alg->cra_blocksize;
  90         rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
  91         rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
  92
  93         if (nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
  94                     sizeof(struct crypto_report_cipher), &rcipher))
  95                 goto nla_put_failure;
  96         return 0;
  97
  98 nla_put_failure:
  99         return -EMSGSIZE;
 100 }
 101
 102 static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
 103 {
 104         struct crypto_report_comp rcomp;
 105
 106         strncpy(rcomp.type, "compression", sizeof(rcomp.type));
 107         if (nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS,
 108                     sizeof(struct crypto_report_comp), &rcomp))
 109                 goto nla_put_failure;
 110         return 0;
 111
 112 nla_put_failure:
 113         return -EMSGSIZE;
 114 }
 115
 116 static int crypto_report_one(struct crypto_alg *alg,
 117                              struct crypto_user_alg *ualg, struct sk_buff *skb)
 118 {
 119         strncpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
 120         strncpy(ualg->cru_driver_name, alg->cra_driver_name,
 121                 sizeof(ualg->cru_driver_name));
 122         strncpy(ualg->cru_module_name, module_name(alg->cra_module),
 123                 sizeof(ualg->cru_module_name));
 124
 125         ualg->cru_type = 0;
 126         ualg->cru_mask = 0;
 127         ualg->cru_flags = alg->cra_flags;
 128         ualg->cru_refcnt = refcount_read(&alg->cra_refcnt);
 129
 130         if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
 131                 goto nla_put_failure;
 132         if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
 133                 struct crypto_report_larval rl;
 134
 135                 strncpy(rl.type, "larval", sizeof(rl.type));
 136                 if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL,
 137                             sizeof(struct crypto_report_larval), &rl))
 138                         goto nla_put_failure;
 139                 goto out;
 140         }
 141
 142         if (alg->cra_type && alg->cra_type->report) {
 143                 if (alg->cra_type->report(skb, alg))
 144                         goto nla_put_failure;
 145
 146                 goto out;
 147         }
 148
 149         switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
 150         case CRYPTO_ALG_TYPE_CIPHER:
 151                 if (crypto_report_cipher(skb, alg))
 152                         goto nla_put_failure;
 153
 154                 break;
 155         case CRYPTO_ALG_TYPE_COMPRESS:
 156                 if (crypto_report_comp(skb, alg))
 157                         goto nla_put_failure;
 158
 159                 break;
 160         }
 161
 162 out:
 163         return 0;
 164
 165 nla_put_failure:
 166         return -EMSGSIZE;
 167 }
 168
 169 static int crypto_report_alg(struct crypto_alg *alg,
 170                              struct crypto_dump_info *info)
 171 {
 172         struct sk_buff *in_skb = info->in_skb;
 173         struct sk_buff *skb = info->out_skb;
 174         struct nlmsghdr *nlh;
 175         struct crypto_user_alg *ualg;
 176         int err = 0;
 177
 178         nlh = nlmsg_put(skb, NETLINK_CB(in_skb).portid, info->nlmsg_seq,
 179                         CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
 180         if (!nlh) {
 181                 err = -EMSGSIZE;
 182                 goto out;
 183         }
 184
 185         ualg = nlmsg_data(nlh);
 186
 187         err = crypto_report_one(alg, ualg, skb);
 188         if (err) {
 189                 nlmsg_cancel(skb, nlh);
 190                 goto out;
 191         }
 192
 193         nlmsg_end(skb, nlh);
 194
 195 out:
 196         return err;
 197 }
 198
 199 static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
 200                          struct nlattr **attrs)
 201 {
 202         struct crypto_user_alg *p = nlmsg_data(in_nlh);
 203         struct crypto_alg *alg;
 204         struct sk_buff *skb;
 205         struct crypto_dump_info info;
 206         int err;
 207
 208         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 209                 return -EINVAL;
 210
 211         alg = crypto_alg_match(p, 0);
 212         if (!alg)
 213                 return -ENOENT;
 214
 215         err = -ENOMEM;
 216         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 217         if (!skb)
 218                 goto drop_alg;
 219
 220         info.in_skb = in_skb;
 221         info.out_skb = skb;
 222         info.nlmsg_seq = in_nlh->nlmsg_seq;
 223         info.nlmsg_flags = 0;
 224
 225         err = crypto_report_alg(alg, &info);
 226
 227 drop_alg:
 228         crypto_mod_put(alg);
 229
 230         if (err)
 231                 return err;
 232
 233         return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
 234 }
 235
 236 static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
 237 {
 238         struct crypto_alg *alg;
 239         struct crypto_dump_info info;
 240         int err;
 241
 242         if (cb->args[0])
 243                 goto out;
 244
 245         cb->args[0] = 1;
 246
 247         info.in_skb = cb->skb;
 248         info.out_skb = skb;
 249         info.nlmsg_seq = cb->nlh->nlmsg_seq;
 250         info.nlmsg_flags = NLM_F_MULTI;
 251
 252         list_for_each_entry(alg, &crypto_alg_list, cra_list) {
 253                 err = crypto_report_alg(alg, &info);
 254                 if (err)
 255                         goto out_err;
 256         }
 257
 258 out:
 259         return skb->len;
 260 out_err:
 261         return err;
 262 }
 263
 264 static int crypto_dump_report_done(struct netlink_callback *cb)
 265 {
 266         return 0;
 267 }
 268
 269 static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 270                              struct nlattr **attrs)
 271 {
 272         struct crypto_alg *alg;
 273         struct crypto_user_alg *p = nlmsg_data(nlh);
 274         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 275         LIST_HEAD(list);
 276
 277         if (!netlink_capable(skb, CAP_NET_ADMIN))
 278                 return -EPERM;
 279
 280         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 281                 return -EINVAL;
 282
 283         if (priority && !strlen(p->cru_driver_name))
 284                 return -EINVAL;
 285
 286         alg = crypto_alg_match(p, 1);
 287         if (!alg)
 288                 return -ENOENT;
 289
 290         down_write(&crypto_alg_sem);
 291
 292         crypto_remove_spawns(alg, &list, NULL);
 293
 294         if (priority)
 295                 alg->cra_priority = nla_get_u32(priority);
 296
 297         up_write(&crypto_alg_sem);
 298
 299         crypto_mod_put(alg);
 300         crypto_remove_final(&list);
 301
 302         return 0;
 303 }
 304
 305 static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 306                           struct nlattr **attrs)
 307 {
 308         struct crypto_alg *alg;
 309         struct crypto_user_alg *p = nlmsg_data(nlh);
 310         int err;
 311
 312         if (!netlink_capable(skb, CAP_NET_ADMIN))
 313                 return -EPERM;
 314
 315         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 316                 return -EINVAL;
 317
 318         alg = crypto_alg_match(p, 1);
 319         if (!alg)
 320                 return -ENOENT;
 321
 322         /* We can not unregister core algorithms such as aes-generic.
 323          * We would loose the reference in the crypto_alg_list to this algorithm
 324          * if we try to unregister. Unregistering such an algorithm without
 325          * removing the module is not possible, so we restrict to crypto
 326          * instances that are build from templates. */
 327         err = -EINVAL;
 328         if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
 329                 goto drop_alg;
 330
 331         err = -EBUSY;
 332         if (refcount_read(&alg->cra_refcnt) > 2)
 333                 goto drop_alg;
 334
 335         err = crypto_unregister_instance((struct crypto_instance *)alg);
 336
 337 drop_alg:
 338         crypto_mod_put(alg);
 339         return err;
 340 }
 341
 342 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 343                           struct nlattr **attrs)
 344 {
 345         int exact = 0;
 346         const char *name;
 347         struct crypto_alg *alg;
 348         struct crypto_user_alg *p = nlmsg_data(nlh);
 349         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 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         if (strlen(p->cru_driver_name))
 358                 exact = 1;
 359
 360         if (priority && !exact)
 361                 return -EINVAL;
 362
 363         alg = crypto_alg_match(p, exact);
 364         if (alg) {
 365                 crypto_mod_put(alg);
 366                 return -EEXIST;
 367         }
 368
 369         if (strlen(p->cru_driver_name))
 370                 name = p->cru_driver_name;
 371         else
 372                 name = p->cru_name;
 373
 374         alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
 375         if (IS_ERR(alg))
 376                 return PTR_ERR(alg);
 377
 378         down_write(&crypto_alg_sem);
 379
 380         if (priority)
 381                 alg->cra_priority = nla_get_u32(priority);
 382
 383         up_write(&crypto_alg_sem);
 384
 385         crypto_mod_put(alg);
 386
 387         return 0;
 388 }
 389
 390 static int crypto_del_rng(struct sk_buff *skb, struct nlmsghdr *nlh,
 391                           struct nlattr **attrs)
 392 {
 393         if (!netlink_capable(skb, CAP_NET_ADMIN))
 394                 return -EPERM;
 395         return crypto_del_default_rng();
 396 }
 397
 398 #define MSGSIZE(type) sizeof(struct type)
 399
 400 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
 401         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 402         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 403         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 404         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 405         [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = 0,
 406         [CRYPTO_MSG_GETSTAT     - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 407 };
 408
 409 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
 410         [CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
 411 };
 412
 413 #undef MSGSIZE
 414
 415 static const struct crypto_link {
 416         int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
 417         int (*dump)(struct sk_buff *, struct netlink_callback *);
 418         int (*done)(struct netlink_callback *);
 419 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
 420         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
 421         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
 422         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
 423         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = { .doit = crypto_report,
 424                                                        .dump = crypto_dump_report,
 425                                                        .done = crypto_dump_report_done},
 426         [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_rng },
 427         [CRYPTO_MSG_GETSTAT     - CRYPTO_MSG_BASE] = { .doit = crypto_reportstat,
 428                                                        .dump = crypto_dump_reportstat,
 429                                                        .done = crypto_dump_reportstat_done},
 430 };
 431
 432 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
 433                                struct netlink_ext_ack *extack)
 434 {
 435         struct nlattr *attrs[CRYPTOCFGA_MAX+1];
 436         const struct crypto_link *link;
 437         int type, err;
 438
 439         type = nlh->nlmsg_type;
 440         if (type > CRYPTO_MSG_MAX)
 441                 return -EINVAL;
 442
 443         type -= CRYPTO_MSG_BASE;
 444         link = &crypto_dispatch[type];
 445
 446         if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
 447             (nlh->nlmsg_flags & NLM_F_DUMP))) {
 448                 struct crypto_alg *alg;
 449                 u16 dump_alloc = 0;
 450
 451                 if (link->dump == NULL)
 452                         return -EINVAL;
 453
 454                 down_read(&crypto_alg_sem);
 455                 list_for_each_entry(alg, &crypto_alg_list, cra_list)
 456                         dump_alloc += CRYPTO_REPORT_MAXSIZE;
 457
 458                 {
 459                         struct netlink_dump_control c = {
 460                                 .dump = link->dump,
 461                                 .done = link->done,
 462                                 .min_dump_alloc = dump_alloc,
 463                         };
 464                         err = netlink_dump_start(crypto_nlsk, skb, nlh, &c);
 465                 }
 466                 up_read(&crypto_alg_sem);
 467
 468                 return err;
 469         }
 470
 471         err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
 472                           crypto_policy, extack);
 473         if (err < 0)
 474                 return err;
 475
 476         if (link->doit == NULL)
 477                 return -EINVAL;
 478
 479         return link->doit(skb, nlh, attrs);
 480 }
 481
 482 static void crypto_netlink_rcv(struct sk_buff *skb)
 483 {
 484         mutex_lock(&crypto_cfg_mutex);
 485         netlink_rcv_skb(skb, &crypto_user_rcv_msg);
 486         mutex_unlock(&crypto_cfg_mutex);
 487 }
 488
 489 static int __init crypto_user_init(void)
 490 {
 491         struct netlink_kernel_cfg cfg = {
 492                 .input  = crypto_netlink_rcv,
 493         };
 494
 495         crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO, &cfg);
 496         if (!crypto_nlsk)
 497                 return -ENOMEM;
 498
 499         return 0;
 500 }
 501
 502 static void __exit crypto_user_exit(void)
 503 {
 504         netlink_kernel_release(crypto_nlsk);
 505 }
 506
 507 module_init(crypto_user_init);
 508 module_exit(crypto_user_exit);
 509 MODULE_LICENSE("GPL");
 510 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 511 MODULE_DESCRIPTION("Crypto userspace configuration API");
 512 MODULE_ALIAS("net-pf-16-proto-21");