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                 return err;
 218
 219         return nlmsg_unicast(net->crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
 220 }
 221
 222 static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
 223 {
 224         const size_t start_pos = cb->args[0];
 225         size_t pos = 0;
 226         struct crypto_dump_info info;
 227         struct crypto_alg *alg;
 228         int res;
 229
 230         info.in_skb = cb->skb;
 231         info.out_skb = skb;
 232         info.nlmsg_seq = cb->nlh->nlmsg_seq;
 233         info.nlmsg_flags = NLM_F_MULTI;
 234
 235         down_read(&crypto_alg_sem);
 236         list_for_each_entry(alg, &crypto_alg_list, cra_list) {
 237                 if (pos >= start_pos) {
 238                         res = crypto_report_alg(alg, &info);
 239                         if (res == -EMSGSIZE)
 240                                 break;
 241                         if (res)
 242                                 goto out;
 243                 }
 244                 pos++;
 245         }
 246         cb->args[0] = pos;
 247         res = skb->len;
 248 out:
 249         up_read(&crypto_alg_sem);
 250         return res;
 251 }
 252
 253 static int crypto_dump_report_done(struct netlink_callback *cb)
 254 {
 255         return 0;
 256 }
 257
 258 static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 259                              struct nlattr **attrs)
 260 {
 261         struct crypto_alg *alg;
 262         struct crypto_user_alg *p = nlmsg_data(nlh);
 263         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 264         LIST_HEAD(list);
 265
 266         if (!netlink_capable(skb, CAP_NET_ADMIN))
 267                 return -EPERM;
 268
 269         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 270                 return -EINVAL;
 271
 272         if (priority && !strlen(p->cru_driver_name))
 273                 return -EINVAL;
 274
 275         alg = crypto_alg_match(p, 1);
 276         if (!alg)
 277                 return -ENOENT;
 278
 279         down_write(&crypto_alg_sem);
 280
 281         crypto_remove_spawns(alg, &list, NULL);
 282
 283         if (priority)
 284                 alg->cra_priority = nla_get_u32(priority);
 285
 286         up_write(&crypto_alg_sem);
 287
 288         crypto_mod_put(alg);
 289         crypto_remove_final(&list);
 290
 291         return 0;
 292 }
 293
 294 static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 295                           struct nlattr **attrs)
 296 {
 297         struct crypto_alg *alg;
 298         struct crypto_user_alg *p = nlmsg_data(nlh);
 299         int err;
 300
 301         if (!netlink_capable(skb, CAP_NET_ADMIN))
 302                 return -EPERM;
 303
 304         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 305                 return -EINVAL;
 306
 307         alg = crypto_alg_match(p, 1);
 308         if (!alg)
 309                 return -ENOENT;
 310
 311         /* We can not unregister core algorithms such as aes-generic.
 312          * We would loose the reference in the crypto_alg_list to this algorithm
 313          * if we try to unregister. Unregistering such an algorithm without
 314          * removing the module is not possible, so we restrict to crypto
 315          * instances that are build from templates. */
 316         err = -EINVAL;
 317         if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
 318                 goto drop_alg;
 319
 320         err = -EBUSY;
 321         if (refcount_read(&alg->cra_refcnt) > 2)
 322                 goto drop_alg;
 323
 324         err = crypto_unregister_instance((struct crypto_instance *)alg);
 325
 326 drop_alg:
 327         crypto_mod_put(alg);
 328         return err;
 329 }
 330
 331 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 332                           struct nlattr **attrs)
 333 {
 334         int exact = 0;
 335         const char *name;
 336         struct crypto_alg *alg;
 337         struct crypto_user_alg *p = nlmsg_data(nlh);
 338         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 339
 340         if (!netlink_capable(skb, CAP_NET_ADMIN))
 341                 return -EPERM;
 342
 343         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 344                 return -EINVAL;
 345
 346         if (strlen(p->cru_driver_name))
 347                 exact = 1;
 348
 349         if (priority && !exact)
 350                 return -EINVAL;
 351
 352         alg = crypto_alg_match(p, exact);
 353         if (alg) {
 354                 crypto_mod_put(alg);
 355                 return -EEXIST;
 356         }
 357
 358         if (strlen(p->cru_driver_name))
 359                 name = p->cru_driver_name;
 360         else
 361                 name = p->cru_name;
 362
 363         alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
 364         if (IS_ERR(alg))
 365                 return PTR_ERR(alg);
 366
 367         down_write(&crypto_alg_sem);
 368
 369         if (priority)
 370                 alg->cra_priority = nla_get_u32(priority);
 371
 372         up_write(&crypto_alg_sem);
 373
 374         crypto_mod_put(alg);
 375
 376         return 0;
 377 }
 378
 379 static int crypto_del_rng(struct sk_buff *skb, struct nlmsghdr *nlh,
 380                           struct nlattr **attrs)
 381 {
 382         if (!netlink_capable(skb, CAP_NET_ADMIN))
 383                 return -EPERM;
 384         return crypto_del_default_rng();
 385 }
 386
 387 #define MSGSIZE(type) sizeof(struct type)
 388
 389 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
 390         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 391         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 392         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 393         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 394         [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = 0,
 395         [CRYPTO_MSG_GETSTAT     - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 396 };
 397
 398 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
 399         [CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
 400 };
 401
 402 #undef MSGSIZE
 403
 404 static const struct crypto_link {
 405         int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
 406         int (*dump)(struct sk_buff *, struct netlink_callback *);
 407         int (*done)(struct netlink_callback *);
 408 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
 409         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
 410         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
 411         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
 412         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = { .doit = crypto_report,
 413                                                        .dump = crypto_dump_report,
 414                                                        .done = crypto_dump_report_done},
 415         [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_rng },
 416         [CRYPTO_MSG_GETSTAT     - CRYPTO_MSG_BASE] = { .doit = crypto_reportstat},
 417 };
 418
 419 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
 420                                struct netlink_ext_ack *extack)
 421 {
 422         struct net *net = sock_net(skb->sk);
 423         struct nlattr *attrs[CRYPTOCFGA_MAX+1];
 424         const struct crypto_link *link;
 425         int type, err;
 426
 427         type = nlh->nlmsg_type;
 428         if (type > CRYPTO_MSG_MAX)
 429                 return -EINVAL;
 430
 431         type -= CRYPTO_MSG_BASE;
 432         link = &crypto_dispatch[type];
 433
 434         if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
 435             (nlh->nlmsg_flags & NLM_F_DUMP))) {
 436                 struct crypto_alg *alg;
 437                 unsigned long dump_alloc = 0;
 438
 439                 if (link->dump == NULL)
 440                         return -EINVAL;
 441
 442                 down_read(&crypto_alg_sem);
 443                 list_for_each_entry(alg, &crypto_alg_list, cra_list)
 444                         dump_alloc += CRYPTO_REPORT_MAXSIZE;
 445                 up_read(&crypto_alg_sem);
 446
 447                 {
 448                         struct netlink_dump_control c = {
 449                                 .dump = link->dump,
 450                                 .done = link->done,
 451                                 .min_dump_alloc = min(dump_alloc, 65535UL),
 452                         };
 453                         err = netlink_dump_start(net->crypto_nlsk, skb, nlh, &c);
 454                 }
 455
 456                 return err;
 457         }
 458
 459         err = nlmsg_parse_deprecated(nlh, crypto_msg_min[type], attrs,
 460                                      CRYPTOCFGA_MAX, crypto_policy, extack);
 461         if (err < 0)
 462                 return err;
 463
 464         if (link->doit == NULL)
 465                 return -EINVAL;
 466
 467         return link->doit(skb, nlh, attrs);
 468 }
 469
 470 static void crypto_netlink_rcv(struct sk_buff *skb)
 471 {
 472         mutex_lock(&crypto_cfg_mutex);
 473         netlink_rcv_skb(skb, &crypto_user_rcv_msg);
 474         mutex_unlock(&crypto_cfg_mutex);
 475 }
 476
 477 static int __net_init crypto_netlink_init(struct net *net)
 478 {
 479         struct netlink_kernel_cfg cfg = {
 480                 .input  = crypto_netlink_rcv,
 481         };
 482
 483         net->crypto_nlsk = netlink_kernel_create(net, NETLINK_CRYPTO, &cfg);
 484         return net->crypto_nlsk == NULL ? -ENOMEM : 0;
 485 }
 486
 487 static void __net_exit crypto_netlink_exit(struct net *net)
 488 {
 489         netlink_kernel_release(net->crypto_nlsk);
 490         net->crypto_nlsk = NULL;
 491 }
 492
 493 static struct pernet_operations crypto_netlink_net_ops = {
 494         .init = crypto_netlink_init,
 495         .exit = crypto_netlink_exit,
 496 };
 497
 498 static int __init crypto_user_init(void)
 499 {
 500         return register_pernet_subsys(&crypto_netlink_net_ops);
 501 }
 502
 503 static void __exit crypto_user_exit(void)
 504 {
 505         unregister_pernet_subsys(&crypto_netlink_net_ops);
 506 }
 507
 508 module_init(crypto_user_init);
 509 module_exit(crypto_user_exit);
 510 MODULE_LICENSE("GPL");
 511 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 512 MODULE_DESCRIPTION("Crypto userspace configuration API");
 513 MODULE_ALIAS("net-pf-16-proto-21");