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         err = crypto_unregister_instance((struct crypto_instance *)alg);
 327
 328 drop_alg:
 329         crypto_mod_put(alg);
 330         return err;
 331 }
 332
 333 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 334                           struct nlattr **attrs)
 335 {
 336         int exact = 0;
 337         const char *name;
 338         struct crypto_alg *alg;
 339         struct crypto_user_alg *p = nlmsg_data(nlh);
 340         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 341
 342         if (!netlink_capable(skb, CAP_NET_ADMIN))
 343                 return -EPERM;
 344
 345         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 346                 return -EINVAL;
 347
 348         if (strlen(p->cru_driver_name))
 349                 exact = 1;
 350
 351         if (priority && !exact)
 352                 return -EINVAL;
 353
 354         alg = crypto_alg_match(p, exact);
 355         if (alg) {
 356                 crypto_mod_put(alg);
 357                 return -EEXIST;
 358         }
 359
 360         if (strlen(p->cru_driver_name))
 361                 name = p->cru_driver_name;
 362         else
 363                 name = p->cru_name;
 364
 365         alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
 366         if (IS_ERR(alg))
 367                 return PTR_ERR(alg);
 368
 369         down_write(&crypto_alg_sem);
 370
 371         if (priority)
 372                 alg->cra_priority = nla_get_u32(priority);
 373
 374         up_write(&crypto_alg_sem);
 375
 376         crypto_mod_put(alg);
 377
 378         return 0;
 379 }
 380
 381 static int crypto_del_rng(struct sk_buff *skb, struct nlmsghdr *nlh,
 382                           struct nlattr **attrs)
 383 {
 384         if (!netlink_capable(skb, CAP_NET_ADMIN))
 385                 return -EPERM;
 386         return crypto_del_default_rng();
 387 }
 388
 389 #define MSGSIZE(type) sizeof(struct type)
 390
 391 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
 392         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 393         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 394         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 395         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 396         [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = 0,
 397         [CRYPTO_MSG_GETSTAT     - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 398 };
 399
 400 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
 401         [CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
 402 };
 403
 404 #undef MSGSIZE
 405
 406 static const struct crypto_link {
 407         int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
 408         int (*dump)(struct sk_buff *, struct netlink_callback *);
 409         int (*done)(struct netlink_callback *);
 410 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
 411         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
 412         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
 413         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
 414         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = { .doit = crypto_report,
 415                                                        .dump = crypto_dump_report,
 416                                                        .done = crypto_dump_report_done},
 417         [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_rng },
 418         [CRYPTO_MSG_GETSTAT     - CRYPTO_MSG_BASE] = { .doit = crypto_reportstat},
 419 };
 420
 421 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
 422                                struct netlink_ext_ack *extack)
 423 {
 424         struct net *net = sock_net(skb->sk);
 425         struct nlattr *attrs[CRYPTOCFGA_MAX+1];
 426         const struct crypto_link *link;
 427         int type, err;
 428
 429         type = nlh->nlmsg_type;
 430         if (type > CRYPTO_MSG_MAX)
 431                 return -EINVAL;
 432
 433         type -= CRYPTO_MSG_BASE;
 434         link = &crypto_dispatch[type];
 435
 436         if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
 437             (nlh->nlmsg_flags & NLM_F_DUMP))) {
 438                 struct crypto_alg *alg;
 439                 unsigned long dump_alloc = 0;
 440
 441                 if (link->dump == NULL)
 442                         return -EINVAL;
 443
 444                 down_read(&crypto_alg_sem);
 445                 list_for_each_entry(alg, &crypto_alg_list, cra_list)
 446                         dump_alloc += CRYPTO_REPORT_MAXSIZE;
 447                 up_read(&crypto_alg_sem);
 448
 449                 {
 450                         struct netlink_dump_control c = {
 451                                 .dump = link->dump,
 452                                 .done = link->done,
 453                                 .min_dump_alloc = min(dump_alloc, 65535UL),
 454                         };
 455                         err = netlink_dump_start(net->crypto_nlsk, skb, nlh, &c);
 456                 }
 457
 458                 return err;
 459         }
 460
 461         err = nlmsg_parse_deprecated(nlh, crypto_msg_min[type], attrs,
 462                                      CRYPTOCFGA_MAX, crypto_policy, extack);
 463         if (err < 0)
 464                 return err;
 465
 466         if (link->doit == NULL)
 467                 return -EINVAL;
 468
 469         return link->doit(skb, nlh, attrs);
 470 }
 471
 472 static void crypto_netlink_rcv(struct sk_buff *skb)
 473 {
 474         mutex_lock(&crypto_cfg_mutex);
 475         netlink_rcv_skb(skb, &crypto_user_rcv_msg);
 476         mutex_unlock(&crypto_cfg_mutex);
 477 }
 478
 479 static int __net_init crypto_netlink_init(struct net *net)
 480 {
 481         struct netlink_kernel_cfg cfg = {
 482                 .input  = crypto_netlink_rcv,
 483         };
 484
 485         net->crypto_nlsk = netlink_kernel_create(net, NETLINK_CRYPTO, &cfg);
 486         return net->crypto_nlsk == NULL ? -ENOMEM : 0;
 487 }
 488
 489 static void __net_exit crypto_netlink_exit(struct net *net)
 490 {
 491         netlink_kernel_release(net->crypto_nlsk);
 492         net->crypto_nlsk = NULL;
 493 }
 494
 495 static struct pernet_operations crypto_netlink_net_ops = {
 496         .init = crypto_netlink_init,
 497         .exit = crypto_netlink_exit,
 498 };
 499
 500 static int __init crypto_user_init(void)
 501 {
 502         return register_pernet_subsys(&crypto_netlink_net_ops);
 503 }
 504
 505 static void __exit crypto_user_exit(void)
 506 {
 507         unregister_pernet_subsys(&crypto_netlink_net_ops);
 508 }
 509
 510 module_init(crypto_user_init);
 511 module_exit(crypto_user_exit);
 512 MODULE_LICENSE("GPL");
 513 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 514 MODULE_DESCRIPTION("Crypto userspace configuration API");
 515 MODULE_ALIAS("net-pf-16-proto-21");