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 ((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 crypto_user_alg *p = nlmsg_data(in_nlh);
 187         struct crypto_alg *alg;
 188         struct sk_buff *skb;
 189         struct crypto_dump_info info;
 190         int err;
 191
 192         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 193                 return -EINVAL;
 194
 195         alg = crypto_alg_match(p, 0);
 196         if (!alg)
 197                 return -ENOENT;
 198
 199         err = -ENOMEM;
 200         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 201         if (!skb)
 202                 goto drop_alg;
 203
 204         info.in_skb = in_skb;
 205         info.out_skb = skb;
 206         info.nlmsg_seq = in_nlh->nlmsg_seq;
 207         info.nlmsg_flags = 0;
 208
 209         err = crypto_report_alg(alg, &info);
 210
 211 drop_alg:
 212         crypto_mod_put(alg);
 213
 214         if (err)
 215                 return err;
 216
 217         return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
 218 }
 219
 220 static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
 221 {
 222         const size_t start_pos = cb->args[0];
 223         size_t pos = 0;
 224         struct crypto_dump_info info;
 225         struct crypto_alg *alg;
 226         int res;
 227
 228         info.in_skb = cb->skb;
 229         info.out_skb = skb;
 230         info.nlmsg_seq = cb->nlh->nlmsg_seq;
 231         info.nlmsg_flags = NLM_F_MULTI;
 232
 233         down_read(&crypto_alg_sem);
 234         list_for_each_entry(alg, &crypto_alg_list, cra_list) {
 235                 if (pos >= start_pos) {
 236                         res = crypto_report_alg(alg, &info);
 237                         if (res == -EMSGSIZE)
 238                                 break;
 239                         if (res)
 240                                 goto out;
 241                 }
 242                 pos++;
 243         }
 244         cb->args[0] = pos;
 245         res = skb->len;
 246 out:
 247         up_read(&crypto_alg_sem);
 248         return res;
 249 }
 250
 251 static int crypto_dump_report_done(struct netlink_callback *cb)
 252 {
 253         return 0;
 254 }
 255
 256 static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 257                              struct nlattr **attrs)
 258 {
 259         struct crypto_alg *alg;
 260         struct crypto_user_alg *p = nlmsg_data(nlh);
 261         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 262         LIST_HEAD(list);
 263
 264         if (!netlink_capable(skb, CAP_NET_ADMIN))
 265                 return -EPERM;
 266
 267         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 268                 return -EINVAL;
 269
 270         if (priority && !strlen(p->cru_driver_name))
 271                 return -EINVAL;
 272
 273         alg = crypto_alg_match(p, 1);
 274         if (!alg)
 275                 return -ENOENT;
 276
 277         down_write(&crypto_alg_sem);
 278
 279         crypto_remove_spawns(alg, &list, NULL);
 280
 281         if (priority)
 282                 alg->cra_priority = nla_get_u32(priority);
 283
 284         up_write(&crypto_alg_sem);
 285
 286         crypto_mod_put(alg);
 287         crypto_remove_final(&list);
 288
 289         return 0;
 290 }
 291
 292 static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 293                           struct nlattr **attrs)
 294 {
 295         struct crypto_alg *alg;
 296         struct crypto_user_alg *p = nlmsg_data(nlh);
 297         int err;
 298
 299         if (!netlink_capable(skb, CAP_NET_ADMIN))
 300                 return -EPERM;
 301
 302         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 303                 return -EINVAL;
 304
 305         alg = crypto_alg_match(p, 1);
 306         if (!alg)
 307                 return -ENOENT;
 308
 309         /* We can not unregister core algorithms such as aes-generic.
 310          * We would loose the reference in the crypto_alg_list to this algorithm
 311          * if we try to unregister. Unregistering such an algorithm without
 312          * removing the module is not possible, so we restrict to crypto
 313          * instances that are build from templates. */
 314         err = -EINVAL;
 315         if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
 316                 goto drop_alg;
 317
 318         err = -EBUSY;
 319         if (refcount_read(&alg->cra_refcnt) > 2)
 320                 goto drop_alg;
 321
 322         err = crypto_unregister_instance((struct crypto_instance *)alg);
 323
 324 drop_alg:
 325         crypto_mod_put(alg);
 326         return err;
 327 }
 328
 329 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 330                           struct nlattr **attrs)
 331 {
 332         int exact = 0;
 333         const char *name;
 334         struct crypto_alg *alg;
 335         struct crypto_user_alg *p = nlmsg_data(nlh);
 336         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 337
 338         if (!netlink_capable(skb, CAP_NET_ADMIN))
 339                 return -EPERM;
 340
 341         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 342                 return -EINVAL;
 343
 344         if (strlen(p->cru_driver_name))
 345                 exact = 1;
 346
 347         if (priority && !exact)
 348                 return -EINVAL;
 349
 350         alg = crypto_alg_match(p, exact);
 351         if (alg) {
 352                 crypto_mod_put(alg);
 353                 return -EEXIST;
 354         }
 355
 356         if (strlen(p->cru_driver_name))
 357                 name = p->cru_driver_name;
 358         else
 359                 name = p->cru_name;
 360
 361         alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
 362         if (IS_ERR(alg))
 363                 return PTR_ERR(alg);
 364
 365         down_write(&crypto_alg_sem);
 366
 367         if (priority)
 368                 alg->cra_priority = nla_get_u32(priority);
 369
 370         up_write(&crypto_alg_sem);
 371
 372         crypto_mod_put(alg);
 373
 374         return 0;
 375 }
 376
 377 static int crypto_del_rng(struct sk_buff *skb, struct nlmsghdr *nlh,
 378                           struct nlattr **attrs)
 379 {
 380         if (!netlink_capable(skb, CAP_NET_ADMIN))
 381                 return -EPERM;
 382         return crypto_del_default_rng();
 383 }
 384
 385 #define MSGSIZE(type) sizeof(struct type)
 386
 387 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
 388         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 389         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 390         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 391         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 392         [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = 0,
 393         [CRYPTO_MSG_GETSTAT     - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 394 };
 395
 396 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
 397         [CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
 398 };
 399
 400 #undef MSGSIZE
 401
 402 static const struct crypto_link {
 403         int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
 404         int (*dump)(struct sk_buff *, struct netlink_callback *);
 405         int (*done)(struct netlink_callback *);
 406 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
 407         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
 408         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
 409         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
 410         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = { .doit = crypto_report,
 411                                                        .dump = crypto_dump_report,
 412                                                        .done = crypto_dump_report_done},
 413         [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_rng },
 414         [CRYPTO_MSG_GETSTAT     - CRYPTO_MSG_BASE] = { .doit = crypto_reportstat},
 415 };
 416
 417 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
 418                                struct netlink_ext_ack *extack)
 419 {
 420         struct nlattr *attrs[CRYPTOCFGA_MAX+1];
 421         const struct crypto_link *link;
 422         int type, err;
 423
 424         type = nlh->nlmsg_type;
 425         if (type > CRYPTO_MSG_MAX)
 426                 return -EINVAL;
 427
 428         type -= CRYPTO_MSG_BASE;
 429         link = &crypto_dispatch[type];
 430
 431         if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
 432             (nlh->nlmsg_flags & NLM_F_DUMP))) {
 433                 struct crypto_alg *alg;
 434                 unsigned long dump_alloc = 0;
 435
 436                 if (link->dump == NULL)
 437                         return -EINVAL;
 438
 439                 down_read(&crypto_alg_sem);
 440                 list_for_each_entry(alg, &crypto_alg_list, cra_list)
 441                         dump_alloc += CRYPTO_REPORT_MAXSIZE;
 442                 up_read(&crypto_alg_sem);
 443
 444                 {
 445                         struct netlink_dump_control c = {
 446                                 .dump = link->dump,
 447                                 .done = link->done,
 448                                 .min_dump_alloc = min(dump_alloc, 65535UL),
 449                         };
 450                         err = netlink_dump_start(crypto_nlsk, skb, nlh, &c);
 451                 }
 452
 453                 return err;
 454         }
 455
 456         err = nlmsg_parse_deprecated(nlh, crypto_msg_min[type], attrs,
 457                                      CRYPTOCFGA_MAX, crypto_policy, extack);
 458         if (err < 0)
 459                 return err;
 460
 461         if (link->doit == NULL)
 462                 return -EINVAL;
 463
 464         return link->doit(skb, nlh, attrs);
 465 }
 466
 467 static void crypto_netlink_rcv(struct sk_buff *skb)
 468 {
 469         mutex_lock(&crypto_cfg_mutex);
 470         netlink_rcv_skb(skb, &crypto_user_rcv_msg);
 471         mutex_unlock(&crypto_cfg_mutex);
 472 }
 473
 474 static int __init crypto_user_init(void)
 475 {
 476         struct netlink_kernel_cfg cfg = {
 477                 .input  = crypto_netlink_rcv,
 478         };
 479
 480         crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO, &cfg);
 481         if (!crypto_nlsk)
 482                 return -ENOMEM;
 483
 484         return 0;
 485 }
 486
 487 static void __exit crypto_user_exit(void)
 488 {
 489         netlink_kernel_release(crypto_nlsk);
 490 }
 491
 492 module_init(crypto_user_init);
 493 module_exit(crypto_user_exit);
 494 MODULE_LICENSE("GPL");
 495 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 496 MODULE_DESCRIPTION("Crypto userspace configuration API");
 497 MODULE_ALIAS("net-pf-16-proto-21");