crypto/crypto_user_base.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Crypto user configuration API.
   4  *
   5  * Copyright (C) 2011 secunet Security Networks AG
   6  * Copyright (C) 2011 Steffen Klassert <steffen.klassert@secunet.com>
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/crypto.h>
  11 #include <linux/cryptouser.h>
  12 #include <linux/sched.h>
  13 #include <linux/security.h>
  14 #include <net/netlink.h>
  15 #include <net/net_namespace.h>
  16 #include <net/sock.h>
  17 #include <crypto/internal/skcipher.h>
  18 #include <crypto/internal/rng.h>
  19 #include <crypto/akcipher.h>
  20 #include <crypto/kpp.h>
  21 #include <crypto/internal/cryptouser.h>
  22
  23 #include "internal.h"
  24
  25 #define null_terminated(x)      (strnlen(x, sizeof(x)) < sizeof(x))
  26
  27 static DEFINE_MUTEX(crypto_cfg_mutex);
  28
  29 struct crypto_dump_info {
  30         struct sk_buff *in_skb;
  31         struct sk_buff *out_skb;
  32         u32 nlmsg_seq;
  33         u16 nlmsg_flags;
  34 };
  35
  36 struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
  37 {
  38         struct crypto_alg *q, *alg = NULL;
  39
  40         down_read(&crypto_alg_sem);
  41
  42         list_for_each_entry(q, &crypto_alg_list, cra_list) {
  43                 int match = 0;
  44
  45                 if (crypto_is_larval(q))
  46                         continue;
  47
  48                 if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
  49                         continue;
  50
  51                 if (strlen(p->cru_driver_name))
  52                         match = !strcmp(q->cra_driver_name,
  53                                         p->cru_driver_name);
  54                 else if (!exact)
  55                         match = !strcmp(q->cra_name, p->cru_name);
  56
  57                 if (!match)
  58                         continue;
  59
  60                 if (unlikely(!crypto_mod_get(q)))
  61                         continue;
  62
  63                 alg = q;
  64                 break;
  65         }
  66
  67         up_read(&crypto_alg_sem);
  68
  69         return alg;
  70 }
  71
  72 static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
  73 {
  74         struct crypto_report_cipher rcipher;
  75
  76         memset(&rcipher, 0, sizeof(rcipher));
  77
  78         strscpy(rcipher.type, "cipher", sizeof(rcipher.type));
  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         return nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
  85                        sizeof(rcipher), &rcipher);
  86 }
  87
  88 static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
  89 {
  90         struct crypto_report_comp rcomp;
  91
  92         memset(&rcomp, 0, sizeof(rcomp));
  93
  94         strscpy(rcomp.type, "compression", sizeof(rcomp.type));
  95
  96         return nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS, sizeof(rcomp), &rcomp);
  97 }
  98
  99 static int crypto_report_one(struct crypto_alg *alg,
 100                              struct crypto_user_alg *ualg, struct sk_buff *skb)
 101 {
 102         memset(ualg, 0, sizeof(*ualg));
 103
 104         strscpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
 105         strscpy(ualg->cru_driver_name, alg->cra_driver_name,
 106                 sizeof(ualg->cru_driver_name));
 107         strscpy(ualg->cru_module_name, module_name(alg->cra_module),
 108                 sizeof(ualg->cru_module_name));
 109
 110         ualg->cru_type = 0;
 111         ualg->cru_mask = 0;
 112         ualg->cru_flags = alg->cra_flags;
 113         ualg->cru_refcnt = refcount_read(&alg->cra_refcnt);
 114
 115         if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
 116                 goto nla_put_failure;
 117         if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
 118                 struct crypto_report_larval rl;
 119
 120                 memset(&rl, 0, sizeof(rl));
 121                 strscpy(rl.type, "larval", sizeof(rl.type));
 122                 if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL, sizeof(rl), &rl))
 123                         goto nla_put_failure;
 124                 goto out;
 125         }
 126
 127         if (alg->cra_type && alg->cra_type->report) {
 128                 if (alg->cra_type->report(skb, alg))
 129                         goto nla_put_failure;
 130
 131                 goto out;
 132         }
 133
 134         switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
 135         case CRYPTO_ALG_TYPE_CIPHER:
 136                 if (crypto_report_cipher(skb, alg))
 137                         goto nla_put_failure;
 138
 139                 break;
 140         case CRYPTO_ALG_TYPE_COMPRESS:
 141                 if (crypto_report_comp(skb, alg))
 142                         goto nla_put_failure;
 143
 144                 break;
 145         }
 146
 147 out:
 148         return 0;
 149
 150 nla_put_failure:
 151         return -EMSGSIZE;
 152 }
 153
 154 static int crypto_report_alg(struct crypto_alg *alg,
 155                              struct crypto_dump_info *info)
 156 {
 157         struct sk_buff *in_skb = info->in_skb;
 158         struct sk_buff *skb = info->out_skb;
 159         struct nlmsghdr *nlh;
 160         struct crypto_user_alg *ualg;
 161         int err = 0;
 162
 163         nlh = nlmsg_put(skb, NETLINK_CB(in_skb).portid, info->nlmsg_seq,
 164                         CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
 165         if (!nlh) {
 166                 err = -EMSGSIZE;
 167                 goto out;
 168         }
 169
 170         ualg = nlmsg_data(nlh);
 171
 172         err = crypto_report_one(alg, ualg, skb);
 173         if (err) {
 174                 nlmsg_cancel(skb, nlh);
 175                 goto out;
 176         }
 177
 178         nlmsg_end(skb, nlh);
 179
 180 out:
 181         return err;
 182 }
 183
 184 static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
 185                          struct nlattr **attrs)
 186 {
 187         struct net *net = sock_net(in_skb->sk);
 188         struct crypto_user_alg *p = nlmsg_data(in_nlh);
 189         struct crypto_alg *alg;
 190         struct sk_buff *skb;
 191         struct crypto_dump_info info;
 192         int err;
 193
 194         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 195                 return -EINVAL;
 196
 197         alg = crypto_alg_match(p, 0);
 198         if (!alg)
 199                 return -ENOENT;
 200
 201         err = -ENOMEM;
 202         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 203         if (!skb)
 204                 goto drop_alg;
 205
 206         info.in_skb = in_skb;
 207         info.out_skb = skb;
 208         info.nlmsg_seq = in_nlh->nlmsg_seq;
 209         info.nlmsg_flags = 0;
 210
 211         err = crypto_report_alg(alg, &info);
 212
 213 drop_alg:
 214         crypto_mod_put(alg);
 215
 216         if (err) {
 217                 kfree_skb(skb);
 218                 return err;
 219         }
 220
 221         return nlmsg_unicast(net->crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
 222 }
 223
 224 static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
 225 {
 226         const size_t start_pos = cb->args[0];
 227         size_t pos = 0;
 228         struct crypto_dump_info info;
 229         struct crypto_alg *alg;
 230         int res;
 231
 232         info.in_skb = cb->skb;
 233         info.out_skb = skb;
 234         info.nlmsg_seq = cb->nlh->nlmsg_seq;
 235         info.nlmsg_flags = NLM_F_MULTI;
 236
 237         down_read(&crypto_alg_sem);
 238         list_for_each_entry(alg, &crypto_alg_list, cra_list) {
 239                 if (pos >= start_pos) {
 240                         res = crypto_report_alg(alg, &info);
 241                         if (res == -EMSGSIZE)
 242                                 break;
 243                         if (res)
 244                                 goto out;
 245                 }
 246                 pos++;
 247         }
 248         cb->args[0] = pos;
 249         res = skb->len;
 250 out:
 251         up_read(&crypto_alg_sem);
 252         return res;
 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 (!netlink_capable(skb, CAP_NET_ADMIN))
 269                 return -EPERM;
 270
 271         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 272                 return -EINVAL;
 273
 274         if (priority && !strlen(p->cru_driver_name))
 275                 return -EINVAL;
 276
 277         alg = crypto_alg_match(p, 1);
 278         if (!alg)
 279                 return -ENOENT;
 280
 281         down_write(&crypto_alg_sem);
 282
 283         crypto_remove_spawns(alg, &list, NULL);
 284
 285         if (priority)
 286                 alg->cra_priority = nla_get_u32(priority);
 287
 288         up_write(&crypto_alg_sem);
 289
 290         crypto_mod_put(alg);
 291         crypto_remove_final(&list);
 292
 293         return 0;
 294 }
 295
 296 static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 297                           struct nlattr **attrs)
 298 {
 299         struct crypto_alg *alg;
 300         struct crypto_user_alg *p = nlmsg_data(nlh);
 301         int err;
 302
 303         if (!netlink_capable(skb, CAP_NET_ADMIN))
 304                 return -EPERM;
 305
 306         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 307                 return -EINVAL;
 308
 309         alg = crypto_alg_match(p, 1);
 310         if (!alg)
 311                 return -ENOENT;
 312
 313         /* We can not unregister core algorithms such as aes-generic.
 314          * We would loose the reference in the crypto_alg_list to this algorithm
 315          * if we try to unregister. Unregistering such an algorithm without
 316          * removing the module is not possible, so we restrict to crypto
 317          * instances that are build from templates. */
 318         err = -EINVAL;
 319         if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
 320                 goto drop_alg;
 321
 322         err = -EBUSY;
 323         if (refcount_read(&alg->cra_refcnt) > 2)
 324                 goto drop_alg;
 325
 326         crypto_unregister_instance((struct crypto_instance *)alg);
 327         err = 0;
 328
 329 drop_alg:
 330         crypto_mod_put(alg);
 331         return err;
 332 }
 333
 334 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 335                           struct nlattr **attrs)
 336 {
 337         int exact = 0;
 338         const char *name;
 339         struct crypto_alg *alg;
 340         struct crypto_user_alg *p = nlmsg_data(nlh);
 341         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 342
 343         if (!netlink_capable(skb, CAP_NET_ADMIN))
 344                 return -EPERM;
 345
 346         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 347                 return -EINVAL;
 348
 349         if (strlen(p->cru_driver_name))
 350                 exact = 1;
 351
 352         if (priority && !exact)
 353                 return -EINVAL;
 354
 355         alg = crypto_alg_match(p, exact);
 356         if (alg) {
 357                 crypto_mod_put(alg);
 358                 return -EEXIST;
 359         }
 360
 361         if (strlen(p->cru_driver_name))
 362                 name = p->cru_driver_name;
 363         else
 364                 name = p->cru_name;
 365
 366         alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
 367         if (IS_ERR(alg))
 368                 return PTR_ERR(alg);
 369
 370         down_write(&crypto_alg_sem);
 371
 372         if (priority)
 373                 alg->cra_priority = nla_get_u32(priority);
 374
 375         up_write(&crypto_alg_sem);
 376
 377         crypto_mod_put(alg);
 378
 379         return 0;
 380 }
 381
 382 static int crypto_del_rng(struct sk_buff *skb, struct nlmsghdr *nlh,
 383                           struct nlattr **attrs)
 384 {
 385         if (!netlink_capable(skb, CAP_NET_ADMIN))
 386                 return -EPERM;
 387         return crypto_del_default_rng();
 388 }
 389
 390 #define MSGSIZE(type) sizeof(struct type)
 391
 392 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
 393         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 394         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 395         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 396         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 397         [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = 0,
 398         [CRYPTO_MSG_GETSTAT     - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 399 };
 400
 401 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
 402         [CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
 403 };
 404
 405 #undef MSGSIZE
 406
 407 static const struct crypto_link {
 408         int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
 409         int (*dump)(struct sk_buff *, struct netlink_callback *);
 410         int (*done)(struct netlink_callback *);
 411 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
 412         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
 413         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
 414         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
 415         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = { .doit = crypto_report,
 416                                                        .dump = crypto_dump_report,
 417                                                        .done = crypto_dump_report_done},
 418         [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_rng },
 419         [CRYPTO_MSG_GETSTAT     - CRYPTO_MSG_BASE] = { .doit = crypto_reportstat},
 420 };
 421
 422 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
 423                                struct netlink_ext_ack *extack)
 424 {
 425         struct net *net = sock_net(skb->sk);
 426         struct nlattr *attrs[CRYPTOCFGA_MAX+1];
 427         const struct crypto_link *link;
 428         int type, err;
 429
 430         type = nlh->nlmsg_type;
 431         if (type > CRYPTO_MSG_MAX)
 432                 return -EINVAL;
 433
 434         type -= CRYPTO_MSG_BASE;
 435         link = &crypto_dispatch[type];
 436
 437         if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
 438             (nlh->nlmsg_flags & NLM_F_DUMP))) {
 439                 struct crypto_alg *alg;
 440                 unsigned long dump_alloc = 0;
 441
 442                 if (link->dump == NULL)
 443                         return -EINVAL;
 444
 445                 down_read(&crypto_alg_sem);
 446                 list_for_each_entry(alg, &crypto_alg_list, cra_list)
 447                         dump_alloc += CRYPTO_REPORT_MAXSIZE;
 448                 up_read(&crypto_alg_sem);
 449
 450                 {
 451                         struct netlink_dump_control c = {
 452                                 .dump = link->dump,
 453                                 .done = link->done,
 454                                 .min_dump_alloc = min(dump_alloc, 65535UL),
 455                         };
 456                         err = netlink_dump_start(net->crypto_nlsk, skb, nlh, &c);
 457                 }
 458
 459                 return err;
 460         }
 461
 462         err = nlmsg_parse_deprecated(nlh, crypto_msg_min[type], attrs,
 463                                      CRYPTOCFGA_MAX, crypto_policy, extack);
 464         if (err < 0)
 465                 return err;
 466
 467         if (link->doit == NULL)
 468                 return -EINVAL;
 469
 470         return link->doit(skb, nlh, attrs);
 471 }
 472
 473 static void crypto_netlink_rcv(struct sk_buff *skb)
 474 {
 475         mutex_lock(&crypto_cfg_mutex);
 476         netlink_rcv_skb(skb, &crypto_user_rcv_msg);
 477         mutex_unlock(&crypto_cfg_mutex);
 478 }
 479
 480 static int __net_init crypto_netlink_init(struct net *net)
 481 {
 482         struct netlink_kernel_cfg cfg = {
 483                 .input  = crypto_netlink_rcv,
 484         };
 485
 486         net->crypto_nlsk = netlink_kernel_create(net, NETLINK_CRYPTO, &cfg);
 487         return net->crypto_nlsk == NULL ? -ENOMEM : 0;
 488 }
 489
 490 static void __net_exit crypto_netlink_exit(struct net *net)
 491 {
 492         netlink_kernel_release(net->crypto_nlsk);
 493         net->crypto_nlsk = NULL;
 494 }
 495
 496 static struct pernet_operations crypto_netlink_net_ops = {
 497         .init = crypto_netlink_init,
 498         .exit = crypto_netlink_exit,
 499 };
 500
 501 static int __init crypto_user_init(void)
 502 {
 503         return register_pernet_subsys(&crypto_netlink_net_ops);
 504 }
 505
 506 static void __exit crypto_user_exit(void)
 507 {
 508         unregister_pernet_subsys(&crypto_netlink_net_ops);
 509 }
 510
 511 module_init(crypto_user_init);
 512 module_exit(crypto_user_exit);
 513 MODULE_LICENSE("GPL");
 514 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 515 MODULE_DESCRIPTION("Crypto userspace configuration API");
 516 MODULE_ALIAS("net-pf-16-proto-21");