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         memset(&rcipher, 0, sizeof(rcipher));
  88
  89         strscpy(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         return nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
  96                        sizeof(rcipher), &rcipher);
  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         memset(&rcomp, 0, sizeof(rcomp));
 104
 105         strscpy(rcomp.type, "compression", sizeof(rcomp.type));
 106
 107         return nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS, sizeof(rcomp), &rcomp);
 108 }
 109
 110 static int crypto_report_one(struct crypto_alg *alg,
 111                              struct crypto_user_alg *ualg, struct sk_buff *skb)
 112 {
 113         memset(ualg, 0, sizeof(*ualg));
 114
 115         strscpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
 116         strscpy(ualg->cru_driver_name, alg->cra_driver_name,
 117                 sizeof(ualg->cru_driver_name));
 118         strscpy(ualg->cru_module_name, module_name(alg->cra_module),
 119                 sizeof(ualg->cru_module_name));
 120
 121         ualg->cru_type = 0;
 122         ualg->cru_mask = 0;
 123         ualg->cru_flags = alg->cra_flags;
 124         ualg->cru_refcnt = refcount_read(&alg->cra_refcnt);
 125
 126         if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
 127                 goto nla_put_failure;
 128         if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
 129                 struct crypto_report_larval rl;
 130
 131                 memset(&rl, 0, sizeof(rl));
 132                 strscpy(rl.type, "larval", sizeof(rl.type));
 133                 if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL, sizeof(rl), &rl))
 134                         goto nla_put_failure;
 135                 goto out;
 136         }
 137
 138         if (alg->cra_type && alg->cra_type->report) {
 139                 if (alg->cra_type->report(skb, alg))
 140                         goto nla_put_failure;
 141
 142                 goto out;
 143         }
 144
 145         switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
 146         case CRYPTO_ALG_TYPE_CIPHER:
 147                 if (crypto_report_cipher(skb, alg))
 148                         goto nla_put_failure;
 149
 150                 break;
 151         case CRYPTO_ALG_TYPE_COMPRESS:
 152                 if (crypto_report_comp(skb, alg))
 153                         goto nla_put_failure;
 154
 155                 break;
 156         }
 157
 158 out:
 159         return 0;
 160
 161 nla_put_failure:
 162         return -EMSGSIZE;
 163 }
 164
 165 static int crypto_report_alg(struct crypto_alg *alg,
 166                              struct crypto_dump_info *info)
 167 {
 168         struct sk_buff *in_skb = info->in_skb;
 169         struct sk_buff *skb = info->out_skb;
 170         struct nlmsghdr *nlh;
 171         struct crypto_user_alg *ualg;
 172         int err = 0;
 173
 174         nlh = nlmsg_put(skb, NETLINK_CB(in_skb).portid, info->nlmsg_seq,
 175                         CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
 176         if (!nlh) {
 177                 err = -EMSGSIZE;
 178                 goto out;
 179         }
 180
 181         ualg = nlmsg_data(nlh);
 182
 183         err = crypto_report_one(alg, ualg, skb);
 184         if (err) {
 185                 nlmsg_cancel(skb, nlh);
 186                 goto out;
 187         }
 188
 189         nlmsg_end(skb, nlh);
 190
 191 out:
 192         return err;
 193 }
 194
 195 static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
 196                          struct nlattr **attrs)
 197 {
 198         struct crypto_user_alg *p = nlmsg_data(in_nlh);
 199         struct crypto_alg *alg;
 200         struct sk_buff *skb;
 201         struct crypto_dump_info info;
 202         int err;
 203
 204         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 205                 return -EINVAL;
 206
 207         alg = crypto_alg_match(p, 0);
 208         if (!alg)
 209                 return -ENOENT;
 210
 211         err = -ENOMEM;
 212         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 213         if (!skb)
 214                 goto drop_alg;
 215
 216         info.in_skb = in_skb;
 217         info.out_skb = skb;
 218         info.nlmsg_seq = in_nlh->nlmsg_seq;
 219         info.nlmsg_flags = 0;
 220
 221         err = crypto_report_alg(alg, &info);
 222
 223 drop_alg:
 224         crypto_mod_put(alg);
 225
 226         if (err)
 227                 return err;
 228
 229         return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
 230 }
 231
 232 static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
 233 {
 234         struct crypto_alg *alg;
 235         struct crypto_dump_info info;
 236         int err;
 237
 238         if (cb->args[0])
 239                 goto out;
 240
 241         cb->args[0] = 1;
 242
 243         info.in_skb = cb->skb;
 244         info.out_skb = skb;
 245         info.nlmsg_seq = cb->nlh->nlmsg_seq;
 246         info.nlmsg_flags = NLM_F_MULTI;
 247
 248         list_for_each_entry(alg, &crypto_alg_list, cra_list) {
 249                 err = crypto_report_alg(alg, &info);
 250                 if (err)
 251                         goto out_err;
 252         }
 253
 254 out:
 255         return skb->len;
 256 out_err:
 257         return err;
 258 }
 259
 260 static int crypto_dump_report_done(struct netlink_callback *cb)
 261 {
 262         return 0;
 263 }
 264
 265 static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 266                              struct nlattr **attrs)
 267 {
 268         struct crypto_alg *alg;
 269         struct crypto_user_alg *p = nlmsg_data(nlh);
 270         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 271         LIST_HEAD(list);
 272
 273         if (!netlink_capable(skb, CAP_NET_ADMIN))
 274                 return -EPERM;
 275
 276         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 277                 return -EINVAL;
 278
 279         if (priority && !strlen(p->cru_driver_name))
 280                 return -EINVAL;
 281
 282         alg = crypto_alg_match(p, 1);
 283         if (!alg)
 284                 return -ENOENT;
 285
 286         down_write(&crypto_alg_sem);
 287
 288         crypto_remove_spawns(alg, &list, NULL);
 289
 290         if (priority)
 291                 alg->cra_priority = nla_get_u32(priority);
 292
 293         up_write(&crypto_alg_sem);
 294
 295         crypto_mod_put(alg);
 296         crypto_remove_final(&list);
 297
 298         return 0;
 299 }
 300
 301 static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 302                           struct nlattr **attrs)
 303 {
 304         struct crypto_alg *alg;
 305         struct crypto_user_alg *p = nlmsg_data(nlh);
 306         int err;
 307
 308         if (!netlink_capable(skb, CAP_NET_ADMIN))
 309                 return -EPERM;
 310
 311         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 312                 return -EINVAL;
 313
 314         alg = crypto_alg_match(p, 1);
 315         if (!alg)
 316                 return -ENOENT;
 317
 318         /* We can not unregister core algorithms such as aes-generic.
 319          * We would loose the reference in the crypto_alg_list to this algorithm
 320          * if we try to unregister. Unregistering such an algorithm without
 321          * removing the module is not possible, so we restrict to crypto
 322          * instances that are build from templates. */
 323         err = -EINVAL;
 324         if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
 325                 goto drop_alg;
 326
 327         err = -EBUSY;
 328         if (refcount_read(&alg->cra_refcnt) > 2)
 329                 goto drop_alg;
 330
 331         err = crypto_unregister_instance((struct crypto_instance *)alg);
 332
 333 drop_alg:
 334         crypto_mod_put(alg);
 335         return err;
 336 }
 337
 338 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 339                           struct nlattr **attrs)
 340 {
 341         int exact = 0;
 342         const char *name;
 343         struct crypto_alg *alg;
 344         struct crypto_user_alg *p = nlmsg_data(nlh);
 345         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 346
 347         if (!netlink_capable(skb, CAP_NET_ADMIN))
 348                 return -EPERM;
 349
 350         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 351                 return -EINVAL;
 352
 353         if (strlen(p->cru_driver_name))
 354                 exact = 1;
 355
 356         if (priority && !exact)
 357                 return -EINVAL;
 358
 359         alg = crypto_alg_match(p, exact);
 360         if (alg) {
 361                 crypto_mod_put(alg);
 362                 return -EEXIST;
 363         }
 364
 365         if (strlen(p->cru_driver_name))
 366                 name = p->cru_driver_name;
 367         else
 368                 name = p->cru_name;
 369
 370         alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
 371         if (IS_ERR(alg))
 372                 return PTR_ERR(alg);
 373
 374         down_write(&crypto_alg_sem);
 375
 376         if (priority)
 377                 alg->cra_priority = nla_get_u32(priority);
 378
 379         up_write(&crypto_alg_sem);
 380
 381         crypto_mod_put(alg);
 382
 383         return 0;
 384 }
 385
 386 static int crypto_del_rng(struct sk_buff *skb, struct nlmsghdr *nlh,
 387                           struct nlattr **attrs)
 388 {
 389         if (!netlink_capable(skb, CAP_NET_ADMIN))
 390                 return -EPERM;
 391         return crypto_del_default_rng();
 392 }
 393
 394 #define MSGSIZE(type) sizeof(struct type)
 395
 396 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
 397         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 398         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 399         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 400         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 401         [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = 0,
 402         [CRYPTO_MSG_GETSTAT     - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 403 };
 404
 405 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
 406         [CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
 407 };
 408
 409 #undef MSGSIZE
 410
 411 static const struct crypto_link {
 412         int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
 413         int (*dump)(struct sk_buff *, struct netlink_callback *);
 414         int (*done)(struct netlink_callback *);
 415 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
 416         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
 417         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
 418         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
 419         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = { .doit = crypto_report,
 420                                                        .dump = crypto_dump_report,
 421                                                        .done = crypto_dump_report_done},
 422         [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_rng },
 423         [CRYPTO_MSG_GETSTAT     - CRYPTO_MSG_BASE] = { .doit = crypto_reportstat,
 424                                                        .dump = crypto_dump_reportstat,
 425                                                        .done = crypto_dump_reportstat_done},
 426 };
 427
 428 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
 429                                struct netlink_ext_ack *extack)
 430 {
 431         struct nlattr *attrs[CRYPTOCFGA_MAX+1];
 432         const struct crypto_link *link;
 433         int type, err;
 434
 435         type = nlh->nlmsg_type;
 436         if (type > CRYPTO_MSG_MAX)
 437                 return -EINVAL;
 438
 439         type -= CRYPTO_MSG_BASE;
 440         link = &crypto_dispatch[type];
 441
 442         if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
 443             (nlh->nlmsg_flags & NLM_F_DUMP))) {
 444                 struct crypto_alg *alg;
 445                 u16 dump_alloc = 0;
 446
 447                 if (link->dump == NULL)
 448                         return -EINVAL;
 449
 450                 down_read(&crypto_alg_sem);
 451                 list_for_each_entry(alg, &crypto_alg_list, cra_list)
 452                         dump_alloc += CRYPTO_REPORT_MAXSIZE;
 453
 454                 {
 455                         struct netlink_dump_control c = {
 456                                 .dump = link->dump,
 457                                 .done = link->done,
 458                                 .min_dump_alloc = dump_alloc,
 459                         };
 460                         err = netlink_dump_start(crypto_nlsk, skb, nlh, &c);
 461                 }
 462                 up_read(&crypto_alg_sem);
 463
 464                 return err;
 465         }
 466
 467         err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
 468                           crypto_policy, extack);
 469         if (err < 0)
 470                 return err;
 471
 472         if (link->doit == NULL)
 473                 return -EINVAL;
 474
 475         return link->doit(skb, nlh, attrs);
 476 }
 477
 478 static void crypto_netlink_rcv(struct sk_buff *skb)
 479 {
 480         mutex_lock(&crypto_cfg_mutex);
 481         netlink_rcv_skb(skb, &crypto_user_rcv_msg);
 482         mutex_unlock(&crypto_cfg_mutex);
 483 }
 484
 485 static int __init crypto_user_init(void)
 486 {
 487         struct netlink_kernel_cfg cfg = {
 488                 .input  = crypto_netlink_rcv,
 489         };
 490
 491         crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO, &cfg);
 492         if (!crypto_nlsk)
 493                 return -ENOMEM;
 494
 495         return 0;
 496 }
 497
 498 static void __exit crypto_user_exit(void)
 499 {
 500         netlink_kernel_release(crypto_nlsk);
 501 }
 502
 503 module_init(crypto_user_init);
 504 module_exit(crypto_user_exit);
 505 MODULE_LICENSE("GPL");
 506 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 507 MODULE_DESCRIPTION("Crypto userspace configuration API");
 508 MODULE_ALIAS("net-pf-16-proto-21");