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 <net/netlink.h>
  14 #include <linux/security.h>
  15 #include <net/net_namespace.h>
  16 #include <crypto/internal/skcipher.h>
  17 #include <crypto/internal/rng.h>
  18 #include <crypto/akcipher.h>
  19 #include <crypto/kpp.h>
  20 #include <crypto/internal/cryptouser.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 /* The crypto netlink socket */
  29 struct sock *crypto_nlsk;
  30
  31 struct crypto_dump_info {
  32         struct sk_buff *in_skb;
  33         struct sk_buff *out_skb;
  34         u32 nlmsg_seq;
  35         u16 nlmsg_flags;
  36 };
  37
  38 struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
  39 {
  40         struct crypto_alg *q, *alg = NULL;
  41
  42         down_read(&crypto_alg_sem);
  43
  44         list_for_each_entry(q, &crypto_alg_list, cra_list) {
  45                 int match = 0;
  46
  47                 if (crypto_is_larval(q))
  48                         continue;
  49
  50                 if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
  51                         continue;
  52
  53                 if (strlen(p->cru_driver_name))
  54                         match = !strcmp(q->cra_driver_name,
  55                                         p->cru_driver_name);
  56                 else if (!exact)
  57                         match = !strcmp(q->cra_name, p->cru_name);
  58
  59                 if (!match)
  60                         continue;
  61
  62                 if (unlikely(!crypto_mod_get(q)))
  63                         continue;
  64
  65                 alg = q;
  66                 break;
  67         }
  68
  69         up_read(&crypto_alg_sem);
  70
  71         return alg;
  72 }
  73
  74 static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
  75 {
  76         struct crypto_report_cipher rcipher;
  77
  78         memset(&rcipher, 0, sizeof(rcipher));
  79
  80         strscpy(rcipher.type, "cipher", sizeof(rcipher.type));
  81
  82         rcipher.blocksize = alg->cra_blocksize;
  83         rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
  84         rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
  85
  86         return nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
  87                        sizeof(rcipher), &rcipher);
  88 }
  89
  90 static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
  91 {
  92         struct crypto_report_comp rcomp;
  93
  94         memset(&rcomp, 0, sizeof(rcomp));
  95
  96         strscpy(rcomp.type, "compression", sizeof(rcomp.type));
  97
  98         return nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS, sizeof(rcomp), &rcomp);
  99 }
 100
 101 static int crypto_report_one(struct crypto_alg *alg,
 102                              struct crypto_user_alg *ualg, struct sk_buff *skb)
 103 {
 104         memset(ualg, 0, sizeof(*ualg));
 105
 106         strscpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
 107         strscpy(ualg->cru_driver_name, alg->cra_driver_name,
 108                 sizeof(ualg->cru_driver_name));
 109         strscpy(ualg->cru_module_name, module_name(alg->cra_module),
 110                 sizeof(ualg->cru_module_name));
 111
 112         ualg->cru_type = 0;
 113         ualg->cru_mask = 0;
 114         ualg->cru_flags = alg->cra_flags;
 115         ualg->cru_refcnt = refcount_read(&alg->cra_refcnt);
 116
 117         if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
 118                 goto nla_put_failure;
 119         if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
 120                 struct crypto_report_larval rl;
 121
 122                 memset(&rl, 0, sizeof(rl));
 123                 strscpy(rl.type, "larval", sizeof(rl.type));
 124                 if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL, sizeof(rl), &rl))
 125                         goto nla_put_failure;
 126                 goto out;
 127         }
 128
 129         if (alg->cra_type && alg->cra_type->report) {
 130                 if (alg->cra_type->report(skb, alg))
 131                         goto nla_put_failure;
 132
 133                 goto out;
 134         }
 135
 136         switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
 137         case CRYPTO_ALG_TYPE_CIPHER:
 138                 if (crypto_report_cipher(skb, alg))
 139                         goto nla_put_failure;
 140
 141                 break;
 142         case CRYPTO_ALG_TYPE_COMPRESS:
 143                 if (crypto_report_comp(skb, alg))
 144                         goto nla_put_failure;
 145
 146                 break;
 147         }
 148
 149 out:
 150         return 0;
 151
 152 nla_put_failure:
 153         return -EMSGSIZE;
 154 }
 155
 156 static int crypto_report_alg(struct crypto_alg *alg,
 157                              struct crypto_dump_info *info)
 158 {
 159         struct sk_buff *in_skb = info->in_skb;
 160         struct sk_buff *skb = info->out_skb;
 161         struct nlmsghdr *nlh;
 162         struct crypto_user_alg *ualg;
 163         int err = 0;
 164
 165         nlh = nlmsg_put(skb, NETLINK_CB(in_skb).portid, info->nlmsg_seq,
 166                         CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
 167         if (!nlh) {
 168                 err = -EMSGSIZE;
 169                 goto out;
 170         }
 171
 172         ualg = nlmsg_data(nlh);
 173
 174         err = crypto_report_one(alg, ualg, skb);
 175         if (err) {
 176                 nlmsg_cancel(skb, nlh);
 177                 goto out;
 178         }
 179
 180         nlmsg_end(skb, nlh);
 181
 182 out:
 183         return err;
 184 }
 185
 186 static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
 187                          struct nlattr **attrs)
 188 {
 189         struct crypto_user_alg *p = nlmsg_data(in_nlh);
 190         struct crypto_alg *alg;
 191         struct sk_buff *skb;
 192         struct crypto_dump_info info;
 193         int err;
 194
 195         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 196                 return -EINVAL;
 197
 198         alg = crypto_alg_match(p, 0);
 199         if (!alg)
 200                 return -ENOENT;
 201
 202         err = -ENOMEM;
 203         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 204         if (!skb)
 205                 goto drop_alg;
 206
 207         info.in_skb = in_skb;
 208         info.out_skb = skb;
 209         info.nlmsg_seq = in_nlh->nlmsg_seq;
 210         info.nlmsg_flags = 0;
 211
 212         err = crypto_report_alg(alg, &info);
 213
 214 drop_alg:
 215         crypto_mod_put(alg);
 216
 217         if (err)
 218                 return err;
 219
 220         return nlmsg_unicast(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         err = crypto_unregister_instance((struct crypto_instance *)alg);
 326
 327 drop_alg:
 328         crypto_mod_put(alg);
 329         return err;
 330 }
 331
 332 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 333                           struct nlattr **attrs)
 334 {
 335         int exact = 0;
 336         const char *name;
 337         struct crypto_alg *alg;
 338         struct crypto_user_alg *p = nlmsg_data(nlh);
 339         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 340
 341         if (!netlink_capable(skb, CAP_NET_ADMIN))
 342                 return -EPERM;
 343
 344         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 345                 return -EINVAL;
 346
 347         if (strlen(p->cru_driver_name))
 348                 exact = 1;
 349
 350         if (priority && !exact)
 351                 return -EINVAL;
 352
 353         alg = crypto_alg_match(p, exact);
 354         if (alg) {
 355                 crypto_mod_put(alg);
 356                 return -EEXIST;
 357         }
 358
 359         if (strlen(p->cru_driver_name))
 360                 name = p->cru_driver_name;
 361         else
 362                 name = p->cru_name;
 363
 364         alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
 365         if (IS_ERR(alg))
 366                 return PTR_ERR(alg);
 367
 368         down_write(&crypto_alg_sem);
 369
 370         if (priority)
 371                 alg->cra_priority = nla_get_u32(priority);
 372
 373         up_write(&crypto_alg_sem);
 374
 375         crypto_mod_put(alg);
 376
 377         return 0;
 378 }
 379
 380 static int crypto_del_rng(struct sk_buff *skb, struct nlmsghdr *nlh,
 381                           struct nlattr **attrs)
 382 {
 383         if (!netlink_capable(skb, CAP_NET_ADMIN))
 384                 return -EPERM;
 385         return crypto_del_default_rng();
 386 }
 387
 388 #define MSGSIZE(type) sizeof(struct type)
 389
 390 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
 391         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 392         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 393         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 394         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 395         [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = 0,
 396         [CRYPTO_MSG_GETSTAT     - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 397 };
 398
 399 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
 400         [CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
 401 };
 402
 403 #undef MSGSIZE
 404
 405 static const struct crypto_link {
 406         int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
 407         int (*dump)(struct sk_buff *, struct netlink_callback *);
 408         int (*done)(struct netlink_callback *);
 409 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
 410         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
 411         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
 412         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
 413         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = { .doit = crypto_report,
 414                                                        .dump = crypto_dump_report,
 415                                                        .done = crypto_dump_report_done},
 416         [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_rng },
 417         [CRYPTO_MSG_GETSTAT     - CRYPTO_MSG_BASE] = { .doit = crypto_reportstat},
 418 };
 419
 420 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
 421                                struct netlink_ext_ack *extack)
 422 {
 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(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 __init crypto_user_init(void)
 478 {
 479         struct netlink_kernel_cfg cfg = {
 480                 .input  = crypto_netlink_rcv,
 481         };
 482
 483         crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO, &cfg);
 484         if (!crypto_nlsk)
 485                 return -ENOMEM;
 486
 487         return 0;
 488 }
 489
 490 static void __exit crypto_user_exit(void)
 491 {
 492         netlink_kernel_release(crypto_nlsk);
 493 }
 494
 495 module_init(crypto_user_init);
 496 module_exit(crypto_user_exit);
 497 MODULE_LICENSE("GPL");
 498 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 499 MODULE_DESCRIPTION("Crypto userspace configuration API");
 500 MODULE_ALIAS("net-pf-16-proto-21");