crypto/crypto_user_base.c

   1 /*
   2  * Crypto user configuration API.
   3  *
   4  * Copyright (C) 2011 secunet Security Networks AG
   5  * Copyright (C) 2011 Steffen Klassert <steffen.klassert@secunet.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms and conditions of the GNU General Public License,
   9  * version 2, as published by the Free Software Foundation.
  10  *
  11  * This program is distributed in the hope it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  14  * more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along with
  17  * this program; if not, write to the Free Software Foundation, Inc.,
  18  * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  19  */
  20
  21 #include <linux/module.h>
  22 #include <linux/crypto.h>
  23 #include <linux/cryptouser.h>
  24 #include <linux/sched.h>
  25 #include <net/netlink.h>
  26 #include <linux/security.h>
  27 #include <net/net_namespace.h>
  28 #include <crypto/internal/skcipher.h>
  29 #include <crypto/internal/rng.h>
  30 #include <crypto/akcipher.h>
  31 #include <crypto/kpp.h>
  32 #include <crypto/internal/cryptouser.h>
  33
  34 #include "internal.h"
  35
  36 #define null_terminated(x)      (strnlen(x, sizeof(x)) < sizeof(x))
  37
  38 static DEFINE_MUTEX(crypto_cfg_mutex);
  39
  40 /* The crypto netlink socket */
  41 struct sock *crypto_nlsk;
  42
  43 struct crypto_dump_info {
  44         struct sk_buff *in_skb;
  45         struct sk_buff *out_skb;
  46         u32 nlmsg_seq;
  47         u16 nlmsg_flags;
  48 };
  49
  50 struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
  51 {
  52         struct crypto_alg *q, *alg = NULL;
  53
  54         down_read(&crypto_alg_sem);
  55
  56         list_for_each_entry(q, &crypto_alg_list, cra_list) {
  57                 int match = 0;
  58
  59                 if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
  60                         continue;
  61
  62                 if (strlen(p->cru_driver_name))
  63                         match = !strcmp(q->cra_driver_name,
  64                                         p->cru_driver_name);
  65                 else if (!exact)
  66                         match = !strcmp(q->cra_name, p->cru_name);
  67
  68                 if (!match)
  69                         continue;
  70
  71                 if (unlikely(!crypto_mod_get(q)))
  72                         continue;
  73
  74                 alg = q;
  75                 break;
  76         }
  77
  78         up_read(&crypto_alg_sem);
  79
  80         return alg;
  81 }
  82
  83 static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
  84 {
  85         struct crypto_report_cipher rcipher;
  86
  87         memset(&rcipher, 0, sizeof(rcipher));
  88
  89         strscpy(rcipher.type, "cipher", sizeof(rcipher.type));
  90
  91         rcipher.blocksize = alg->cra_blocksize;
  92         rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
  93         rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
  94
  95         return nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
  96                        sizeof(rcipher), &rcipher);
  97 }
  98
  99 static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
 100 {
 101         struct crypto_report_comp rcomp;
 102
 103         memset(&rcomp, 0, sizeof(rcomp));
 104
 105         strscpy(rcomp.type, "compression", sizeof(rcomp.type));
 106
 107         return nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS, sizeof(rcomp), &rcomp);
 108 }
 109
 110 static int crypto_report_one(struct crypto_alg *alg,
 111                              struct crypto_user_alg *ualg, struct sk_buff *skb)
 112 {
 113         memset(ualg, 0, sizeof(*ualg));
 114
 115         strscpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
 116         strscpy(ualg->cru_driver_name, alg->cra_driver_name,
 117                 sizeof(ualg->cru_driver_name));
 118         strscpy(ualg->cru_module_name, module_name(alg->cra_module),
 119                 sizeof(ualg->cru_module_name));
 120
 121         ualg->cru_type = 0;
 122         ualg->cru_mask = 0;
 123         ualg->cru_flags = alg->cra_flags;
 124         ualg->cru_refcnt = refcount_read(&alg->cra_refcnt);
 125
 126         if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
 127                 goto nla_put_failure;
 128         if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
 129                 struct crypto_report_larval rl;
 130
 131                 memset(&rl, 0, sizeof(rl));
 132                 strscpy(rl.type, "larval", sizeof(rl.type));
 133                 if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL, sizeof(rl), &rl))
 134                         goto nla_put_failure;
 135                 goto out;
 136         }
 137
 138         if (alg->cra_type && alg->cra_type->report) {
 139                 if (alg->cra_type->report(skb, alg))
 140                         goto nla_put_failure;
 141
 142                 goto out;
 143         }
 144
 145         switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
 146         case CRYPTO_ALG_TYPE_CIPHER:
 147                 if (crypto_report_cipher(skb, alg))
 148                         goto nla_put_failure;
 149
 150                 break;
 151         case CRYPTO_ALG_TYPE_COMPRESS:
 152                 if (crypto_report_comp(skb, alg))
 153                         goto nla_put_failure;
 154
 155                 break;
 156         }
 157
 158 out:
 159         return 0;
 160
 161 nla_put_failure:
 162         return -EMSGSIZE;
 163 }
 164
 165 static int crypto_report_alg(struct crypto_alg *alg,
 166                              struct crypto_dump_info *info)
 167 {
 168         struct sk_buff *in_skb = info->in_skb;
 169         struct sk_buff *skb = info->out_skb;
 170         struct nlmsghdr *nlh;
 171         struct crypto_user_alg *ualg;
 172         int err = 0;
 173
 174         nlh = nlmsg_put(skb, NETLINK_CB(in_skb).portid, info->nlmsg_seq,
 175                         CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
 176         if (!nlh) {
 177                 err = -EMSGSIZE;
 178                 goto out;
 179         }
 180
 181         ualg = nlmsg_data(nlh);
 182
 183         err = crypto_report_one(alg, ualg, skb);
 184         if (err) {
 185                 nlmsg_cancel(skb, nlh);
 186                 goto out;
 187         }
 188
 189         nlmsg_end(skb, nlh);
 190
 191 out:
 192         return err;
 193 }
 194
 195 static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
 196                          struct nlattr **attrs)
 197 {
 198         struct crypto_user_alg *p = nlmsg_data(in_nlh);
 199         struct crypto_alg *alg;
 200         struct sk_buff *skb;
 201         struct crypto_dump_info info;
 202         int err;
 203
 204         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 205                 return -EINVAL;
 206
 207         alg = crypto_alg_match(p, 0);
 208         if (!alg)
 209                 return -ENOENT;
 210
 211         err = -ENOMEM;
 212         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 213         if (!skb)
 214                 goto drop_alg;
 215
 216         info.in_skb = in_skb;
 217         info.out_skb = skb;
 218         info.nlmsg_seq = in_nlh->nlmsg_seq;
 219         info.nlmsg_flags = 0;
 220
 221         err = crypto_report_alg(alg, &info);
 222
 223 drop_alg:
 224         crypto_mod_put(alg);
 225
 226         if (err)
 227                 return err;
 228
 229         return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
 230 }
 231
 232 static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
 233 {
 234         const size_t start_pos = cb->args[0];
 235         size_t pos = 0;
 236         struct crypto_dump_info info;
 237         struct crypto_alg *alg;
 238         int res;
 239
 240         info.in_skb = cb->skb;
 241         info.out_skb = skb;
 242         info.nlmsg_seq = cb->nlh->nlmsg_seq;
 243         info.nlmsg_flags = NLM_F_MULTI;
 244
 245         down_read(&crypto_alg_sem);
 246         list_for_each_entry(alg, &crypto_alg_list, cra_list) {
 247                 if (pos >= start_pos) {
 248                         res = crypto_report_alg(alg, &info);
 249                         if (res == -EMSGSIZE)
 250                                 break;
 251                         if (res)
 252                                 goto out;
 253                 }
 254                 pos++;
 255         }
 256         cb->args[0] = pos;
 257         res = skb->len;
 258 out:
 259         up_read(&crypto_alg_sem);
 260         return res;
 261 }
 262
 263 static int crypto_dump_report_done(struct netlink_callback *cb)
 264 {
 265         return 0;
 266 }
 267
 268 static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 269                              struct nlattr **attrs)
 270 {
 271         struct crypto_alg *alg;
 272         struct crypto_user_alg *p = nlmsg_data(nlh);
 273         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 274         LIST_HEAD(list);
 275
 276         if (!netlink_capable(skb, CAP_NET_ADMIN))
 277                 return -EPERM;
 278
 279         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 280                 return -EINVAL;
 281
 282         if (priority && !strlen(p->cru_driver_name))
 283                 return -EINVAL;
 284
 285         alg = crypto_alg_match(p, 1);
 286         if (!alg)
 287                 return -ENOENT;
 288
 289         down_write(&crypto_alg_sem);
 290
 291         crypto_remove_spawns(alg, &list, NULL);
 292
 293         if (priority)
 294                 alg->cra_priority = nla_get_u32(priority);
 295
 296         up_write(&crypto_alg_sem);
 297
 298         crypto_mod_put(alg);
 299         crypto_remove_final(&list);
 300
 301         return 0;
 302 }
 303
 304 static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 305                           struct nlattr **attrs)
 306 {
 307         struct crypto_alg *alg;
 308         struct crypto_user_alg *p = nlmsg_data(nlh);
 309         int err;
 310
 311         if (!netlink_capable(skb, CAP_NET_ADMIN))
 312                 return -EPERM;
 313
 314         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 315                 return -EINVAL;
 316
 317         alg = crypto_alg_match(p, 1);
 318         if (!alg)
 319                 return -ENOENT;
 320
 321         /* We can not unregister core algorithms such as aes-generic.
 322          * We would loose the reference in the crypto_alg_list to this algorithm
 323          * if we try to unregister. Unregistering such an algorithm without
 324          * removing the module is not possible, so we restrict to crypto
 325          * instances that are build from templates. */
 326         err = -EINVAL;
 327         if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
 328                 goto drop_alg;
 329
 330         err = -EBUSY;
 331         if (refcount_read(&alg->cra_refcnt) > 2)
 332                 goto drop_alg;
 333
 334         err = crypto_unregister_instance((struct crypto_instance *)alg);
 335
 336 drop_alg:
 337         crypto_mod_put(alg);
 338         return err;
 339 }
 340
 341 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 342                           struct nlattr **attrs)
 343 {
 344         int exact = 0;
 345         const char *name;
 346         struct crypto_alg *alg;
 347         struct crypto_user_alg *p = nlmsg_data(nlh);
 348         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 349
 350         if (!netlink_capable(skb, CAP_NET_ADMIN))
 351                 return -EPERM;
 352
 353         if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 354                 return -EINVAL;
 355
 356         if (strlen(p->cru_driver_name))
 357                 exact = 1;
 358
 359         if (priority && !exact)
 360                 return -EINVAL;
 361
 362         alg = crypto_alg_match(p, exact);
 363         if (alg) {
 364                 crypto_mod_put(alg);
 365                 return -EEXIST;
 366         }
 367
 368         if (strlen(p->cru_driver_name))
 369                 name = p->cru_driver_name;
 370         else
 371                 name = p->cru_name;
 372
 373         alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
 374         if (IS_ERR(alg))
 375                 return PTR_ERR(alg);
 376
 377         down_write(&crypto_alg_sem);
 378
 379         if (priority)
 380                 alg->cra_priority = nla_get_u32(priority);
 381
 382         up_write(&crypto_alg_sem);
 383
 384         crypto_mod_put(alg);
 385
 386         return 0;
 387 }
 388
 389 static int crypto_del_rng(struct sk_buff *skb, struct nlmsghdr *nlh,
 390                           struct nlattr **attrs)
 391 {
 392         if (!netlink_capable(skb, CAP_NET_ADMIN))
 393                 return -EPERM;
 394         return crypto_del_default_rng();
 395 }
 396
 397 #define MSGSIZE(type) sizeof(struct type)
 398
 399 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
 400         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 401         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 402         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 403         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 404         [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = 0,
 405         [CRYPTO_MSG_GETSTAT     - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 406 };
 407
 408 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
 409         [CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
 410 };
 411
 412 #undef MSGSIZE
 413
 414 static const struct crypto_link {
 415         int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
 416         int (*dump)(struct sk_buff *, struct netlink_callback *);
 417         int (*done)(struct netlink_callback *);
 418 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
 419         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
 420         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
 421         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
 422         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = { .doit = crypto_report,
 423                                                        .dump = crypto_dump_report,
 424                                                        .done = crypto_dump_report_done},
 425         [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_rng },
 426         [CRYPTO_MSG_GETSTAT     - CRYPTO_MSG_BASE] = { .doit = crypto_reportstat},
 427 };
 428
 429 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
 430                                struct netlink_ext_ack *extack)
 431 {
 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(crypto_nlsk, skb, nlh, &c);
 463                 }
 464
 465                 return err;
 466         }
 467
 468         err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
 469                           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 __init crypto_user_init(void)
 487 {
 488         struct netlink_kernel_cfg cfg = {
 489                 .input  = crypto_netlink_rcv,
 490         };
 491
 492         crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO, &cfg);
 493         if (!crypto_nlsk)
 494                 return -ENOMEM;
 495
 496         return 0;
 497 }
 498
 499 static void __exit crypto_user_exit(void)
 500 {
 501         netlink_kernel_release(crypto_nlsk);
 502 }
 503
 504 module_init(crypto_user_init);
 505 module_exit(crypto_user_exit);
 506 MODULE_LICENSE("GPL");
 507 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 508 MODULE_DESCRIPTION("Crypto userspace configuration API");
 509 MODULE_ALIAS("net-pf-16-proto-21");