crypto/crypto_user.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
  22 #include "internal.h"
  23
  24 #define null_terminated(x)      (strnlen(x, sizeof(x)) < sizeof(x))
  25
  26 static DEFINE_MUTEX(crypto_cfg_mutex);
  27
  28 struct crypto_dump_info {
  29         struct sk_buff *in_skb;
  30         struct sk_buff *out_skb;
  31         u32 nlmsg_seq;
  32         u16 nlmsg_flags;
  33 };
  34
  35 static struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
  36 {
  37         struct crypto_alg *q, *alg = NULL;
  38
  39         down_read(&crypto_alg_sem);
  40
  41         list_for_each_entry(q, &crypto_alg_list, cra_list) {
  42                 int match = 0;
  43
  44                 if (crypto_is_larval(q))
  45                         continue;
  46
  47                 if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
  48                         continue;
  49
  50                 if (strlen(p->cru_driver_name))
  51                         match = !strcmp(q->cra_driver_name,
  52                                         p->cru_driver_name);
  53                 else if (!exact)
  54                         match = !strcmp(q->cra_name, p->cru_name);
  55
  56                 if (!match)
  57                         continue;
  58
  59                 if (unlikely(!crypto_mod_get(q)))
  60                         continue;
  61
  62                 alg = q;
  63                 break;
  64         }
  65
  66         up_read(&crypto_alg_sem);
  67
  68         return alg;
  69 }
  70
  71 static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
  72 {
  73         struct crypto_report_cipher rcipher;
  74
  75         memset(&rcipher, 0, sizeof(rcipher));
  76
  77         strscpy(rcipher.type, "cipher", sizeof(rcipher.type));
  78
  79         rcipher.blocksize = alg->cra_blocksize;
  80         rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
  81         rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
  82
  83         return nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
  84                        sizeof(rcipher), &rcipher);
  85 }
  86
  87 static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
  88 {
  89         struct crypto_report_comp rcomp;
  90
  91         memset(&rcomp, 0, sizeof(rcomp));
  92
  93         strscpy(rcomp.type, "compression", sizeof(rcomp.type));
  94
  95         return nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS, sizeof(rcomp), &rcomp);
  96 }
  97
  98 static int crypto_report_one(struct crypto_alg *alg,
  99                              struct crypto_user_alg *ualg, struct sk_buff *skb)
 100 {
 101         memset(ualg, 0, sizeof(*ualg));
 102
 103         strscpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
 104         strscpy(ualg->cru_driver_name, alg->cra_driver_name,
 105                 sizeof(ualg->cru_driver_name));
 106         strscpy(ualg->cru_module_name, module_name(alg->cra_module),
 107                 sizeof(ualg->cru_module_name));
 108
 109         ualg->cru_type = 0;
 110         ualg->cru_mask = 0;
 111         ualg->cru_flags = alg->cra_flags;
 112         ualg->cru_refcnt = refcount_read(&alg->cra_refcnt);
 113
 114         if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
 115                 goto nla_put_failure;
 116         if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
 117                 struct crypto_report_larval rl;
 118
 119                 memset(&rl, 0, sizeof(rl));
 120                 strscpy(rl.type, "larval", sizeof(rl.type));
 121                 if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL, sizeof(rl), &rl))
 122                         goto nla_put_failure;
 123                 goto out;
 124         }
 125
 126         if (alg->cra_type && alg->cra_type->report) {
 127                 if (alg->cra_type->report(skb, alg))
 128                         goto nla_put_failure;
 129
 130                 goto out;
 131         }
 132
 133         switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
 134         case CRYPTO_ALG_TYPE_CIPHER:
 135                 if (crypto_report_cipher(skb, alg))
 136                         goto nla_put_failure;
 137
 138                 break;
 139         case CRYPTO_ALG_TYPE_COMPRESS:
 140                 if (crypto_report_comp(skb, alg))
 141                         goto nla_put_failure;
 142
 143                 break;
 144         }
 145
 146 out:
 147         return 0;
 148
 149 nla_put_failure:
 150         return -EMSGSIZE;
 151 }
 152
 153 static int crypto_report_alg(struct crypto_alg *alg,
 154                              struct crypto_dump_info *info)
 155 {
 156         struct sk_buff *in_skb = info->in_skb;
 157         struct sk_buff *skb = info->out_skb;
 158         struct nlmsghdr *nlh;
 159         struct crypto_user_alg *ualg;
 160         int err = 0;
 161
 162         nlh = nlmsg_put(skb, NETLINK_CB(in_skb).portid, info->nlmsg_seq,
 163                         CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
 164         if (!nlh) {
 165                 err = -EMSGSIZE;
 166                 goto out;
 167         }
 168
 169         ualg = nlmsg_data(nlh);
 170
 171         err = crypto_report_one(alg, ualg, skb);
 172         if (err) {
 173                 nlmsg_cancel(skb, nlh);
 174                 goto out;
 175         }
 176
 177         nlmsg_end(skb, nlh);
 178
 179 out:
 180         return err;
 181 }
 182
 183 static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
 184                          struct nlattr **attrs)
 185 {
 186         struct net *net = sock_net(in_skb->sk);
 187         struct crypto_user_alg *p = nlmsg_data(in_nlh);
 188         struct crypto_alg *alg;
 189         struct sk_buff *skb;
 190         struct crypto_dump_info info;
 191         int err;
 192
 193         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 194                 return -EINVAL;
 195
 196         alg = crypto_alg_match(p, 0);
 197         if (!alg)
 198                 return -ENOENT;
 199
 200         err = -ENOMEM;
 201         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 202         if (!skb)
 203                 goto drop_alg;
 204
 205         info.in_skb = in_skb;
 206         info.out_skb = skb;
 207         info.nlmsg_seq = in_nlh->nlmsg_seq;
 208         info.nlmsg_flags = 0;
 209
 210         err = crypto_report_alg(alg, &info);
 211
 212 drop_alg:
 213         crypto_mod_put(alg);
 214
 215         if (err) {
 216                 kfree_skb(skb);
 217                 return err;
 218         }
 219
 220         return nlmsg_unicast(net->crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
 221 }
 222
 223 static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
 224 {
 225         const size_t start_pos = cb->args[0];
 226         size_t pos = 0;
 227         struct crypto_dump_info info;
 228         struct crypto_alg *alg;
 229         int res;
 230
 231         info.in_skb = cb->skb;
 232         info.out_skb = skb;
 233         info.nlmsg_seq = cb->nlh->nlmsg_seq;
 234         info.nlmsg_flags = NLM_F_MULTI;
 235
 236         down_read(&crypto_alg_sem);
 237         list_for_each_entry(alg, &crypto_alg_list, cra_list) {
 238                 if (pos >= start_pos) {
 239                         res = crypto_report_alg(alg, &info);
 240                         if (res == -EMSGSIZE)
 241                                 break;
 242                         if (res)
 243                                 goto out;
 244                 }
 245                 pos++;
 246         }
 247         cb->args[0] = pos;
 248         res = skb->len;
 249 out:
 250         up_read(&crypto_alg_sem);
 251         return res;
 252 }
 253
 254 static int crypto_dump_report_done(struct netlink_callback *cb)
 255 {
 256         return 0;
 257 }
 258
 259 static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 260                              struct nlattr **attrs)
 261 {
 262         struct crypto_alg *alg;
 263         struct crypto_user_alg *p = nlmsg_data(nlh);
 264         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 265         LIST_HEAD(list);
 266
 267         if (!netlink_capable(skb, CAP_NET_ADMIN))
 268                 return -EPERM;
 269
 270         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 271                 return -EINVAL;
 272
 273         if (priority && !strlen(p->cru_driver_name))
 274                 return -EINVAL;
 275
 276         alg = crypto_alg_match(p, 1);
 277         if (!alg)
 278                 return -ENOENT;
 279
 280         down_write(&crypto_alg_sem);
 281
 282         crypto_remove_spawns(alg, &list, NULL);
 283
 284         if (priority)
 285                 alg->cra_priority = nla_get_u32(priority);
 286
 287         up_write(&crypto_alg_sem);
 288
 289         crypto_mod_put(alg);
 290         crypto_remove_final(&list);
 291
 292         return 0;
 293 }
 294
 295 static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 296                           struct nlattr **attrs)
 297 {
 298         struct crypto_alg *alg;
 299         struct crypto_user_alg *p = nlmsg_data(nlh);
 300         int err;
 301
 302         if (!netlink_capable(skb, CAP_NET_ADMIN))
 303                 return -EPERM;
 304
 305         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 306                 return -EINVAL;
 307
 308         alg = crypto_alg_match(p, 1);
 309         if (!alg)
 310                 return -ENOENT;
 311
 312         /* We can not unregister core algorithms such as aes-generic.
 313          * We would loose the reference in the crypto_alg_list to this algorithm
 314          * if we try to unregister. Unregistering such an algorithm without
 315          * removing the module is not possible, so we restrict to crypto
 316          * instances that are build from templates. */
 317         err = -EINVAL;
 318         if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
 319                 goto drop_alg;
 320
 321         err = -EBUSY;
 322         if (refcount_read(&alg->cra_refcnt) > 2)
 323                 goto drop_alg;
 324
 325         crypto_unregister_instance((struct crypto_instance *)alg);
 326         err = 0;
 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 static int crypto_reportstat(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
 390                              struct nlattr **attrs)
 391 {
 392         /* No longer supported */
 393         return -ENOTSUPP;
 394 }
 395
 396 #define MSGSIZE(type) sizeof(struct type)
 397
 398 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
 399         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 400         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 401         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 402         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 403         [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = 0,
 404         [CRYPTO_MSG_GETSTAT     - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 405 };
 406
 407 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
 408         [CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
 409 };
 410
 411 #undef MSGSIZE
 412
 413 static const struct crypto_link {
 414         int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
 415         int (*dump)(struct sk_buff *, struct netlink_callback *);
 416         int (*done)(struct netlink_callback *);
 417 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
 418         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
 419         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
 420         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
 421         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = { .doit = crypto_report,
 422                                                        .dump = crypto_dump_report,
 423                                                        .done = crypto_dump_report_done},
 424         [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_rng },
 425         [CRYPTO_MSG_GETSTAT     - CRYPTO_MSG_BASE] = { .doit = crypto_reportstat},
 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 net *net = sock_net(skb->sk);
 432         struct nlattr *attrs[CRYPTOCFGA_MAX+1];
 433         const struct crypto_link *link;
 434         int type, err;
 435
 436         type = nlh->nlmsg_type;
 437         if (type > CRYPTO_MSG_MAX)
 438                 return -EINVAL;
 439
 440         type -= CRYPTO_MSG_BASE;
 441         link = &crypto_dispatch[type];
 442
 443         if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
 444             (nlh->nlmsg_flags & NLM_F_DUMP))) {
 445                 struct crypto_alg *alg;
 446                 unsigned long dump_alloc = 0;
 447
 448                 if (link->dump == NULL)
 449                         return -EINVAL;
 450
 451                 down_read(&crypto_alg_sem);
 452                 list_for_each_entry(alg, &crypto_alg_list, cra_list)
 453                         dump_alloc += CRYPTO_REPORT_MAXSIZE;
 454                 up_read(&crypto_alg_sem);
 455
 456                 {
 457                         struct netlink_dump_control c = {
 458                                 .dump = link->dump,
 459                                 .done = link->done,
 460                                 .min_dump_alloc = min(dump_alloc, 65535UL),
 461                         };
 462                         err = netlink_dump_start(net->crypto_nlsk, skb, nlh, &c);
 463                 }
 464
 465                 return err;
 466         }
 467
 468         err = nlmsg_parse_deprecated(nlh, crypto_msg_min[type], attrs,
 469                                      CRYPTOCFGA_MAX, crypto_policy, extack);
 470         if (err < 0)
 471                 return err;
 472
 473         if (link->doit == NULL)
 474                 return -EINVAL;
 475
 476         return link->doit(skb, nlh, attrs);
 477 }
 478
 479 static void crypto_netlink_rcv(struct sk_buff *skb)
 480 {
 481         mutex_lock(&crypto_cfg_mutex);
 482         netlink_rcv_skb(skb, &crypto_user_rcv_msg);
 483         mutex_unlock(&crypto_cfg_mutex);
 484 }
 485
 486 static int __net_init crypto_netlink_init(struct net *net)
 487 {
 488         struct netlink_kernel_cfg cfg = {
 489                 .input  = crypto_netlink_rcv,
 490         };
 491
 492         net->crypto_nlsk = netlink_kernel_create(net, NETLINK_CRYPTO, &cfg);
 493         return net->crypto_nlsk == NULL ? -ENOMEM : 0;
 494 }
 495
 496 static void __net_exit crypto_netlink_exit(struct net *net)
 497 {
 498         netlink_kernel_release(net->crypto_nlsk);
 499         net->crypto_nlsk = NULL;
 500 }
 501
 502 static struct pernet_operations crypto_netlink_net_ops = {
 503         .init = crypto_netlink_init,
 504         .exit = crypto_netlink_exit,
 505 };
 506
 507 static int __init crypto_user_init(void)
 508 {
 509         return register_pernet_subsys(&crypto_netlink_net_ops);
 510 }
 511
 512 static void __exit crypto_user_exit(void)
 513 {
 514         unregister_pernet_subsys(&crypto_netlink_net_ops);
 515 }
 516
 517 module_init(crypto_user_init);
 518 module_exit(crypto_user_exit);
 519 MODULE_LICENSE("GPL");
 520 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 521 MODULE_DESCRIPTION("Crypto userspace configuration API");
 522 MODULE_ALIAS("net-pf-16-proto-21");