crypto/crypto_user.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 <net/netlink.h>
  25 #include <linux/security.h>
  26 #include <net/net_namespace.h>
  27 #include "internal.h"
  28
  29 DEFINE_MUTEX(crypto_cfg_mutex);
  30
  31 /* The crypto netlink socket */
  32 static struct sock *crypto_nlsk;
  33
  34 struct crypto_dump_info {
  35         struct sk_buff *in_skb;
  36         struct sk_buff *out_skb;
  37         u32 nlmsg_seq;
  38         u16 nlmsg_flags;
  39 };
  40
  41 static struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
  42 {
  43         struct crypto_alg *q, *alg = NULL;
  44
  45         down_read(&crypto_alg_sem);
  46
  47         if (list_empty(&crypto_alg_list))
  48                 return NULL;
  49
  50         list_for_each_entry(q, &crypto_alg_list, cra_list) {
  51                 int match = 0;
  52
  53                 if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
  54                         continue;
  55
  56                 if (strlen(p->cru_driver_name))
  57                         match = !strcmp(q->cra_driver_name,
  58                                         p->cru_driver_name);
  59                 else if (!exact)
  60                         match = !strcmp(q->cra_name, p->cru_name);
  61
  62                 if (match) {
  63                         alg = q;
  64                         break;
  65                 }
  66         }
  67
  68         up_read(&crypto_alg_sem);
  69
  70         return alg;
  71 }
  72
  73 static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
  74 {
  75         struct crypto_report_cipher rcipher;
  76
  77         snprintf(rcipher.type, CRYPTO_MAX_ALG_NAME, "%s", "cipher");
  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         NLA_PUT(skb, CRYPTOCFGA_REPORT_CIPHER,
  84                 sizeof(struct crypto_report_cipher), &rcipher);
  85
  86         return 0;
  87
  88 nla_put_failure:
  89         return -EMSGSIZE;
  90 }
  91
  92 static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
  93 {
  94         struct crypto_report_comp rcomp;
  95
  96         snprintf(rcomp.type, CRYPTO_MAX_ALG_NAME, "%s", "compression");
  97
  98         NLA_PUT(skb, CRYPTOCFGA_REPORT_COMPRESS,
  99                 sizeof(struct crypto_report_comp), &rcomp);
 100
 101         return 0;
 102
 103 nla_put_failure:
 104         return -EMSGSIZE;
 105 }
 106
 107 static int crypto_report_one(struct crypto_alg *alg,
 108                              struct crypto_user_alg *ualg, struct sk_buff *skb)
 109 {
 110         memcpy(&ualg->cru_name, &alg->cra_name, sizeof(ualg->cru_name));
 111         memcpy(&ualg->cru_driver_name, &alg->cra_driver_name,
 112                sizeof(ualg->cru_driver_name));
 113         memcpy(&ualg->cru_module_name, module_name(alg->cra_module),
 114                CRYPTO_MAX_ALG_NAME);
 115
 116         ualg->cru_flags = alg->cra_flags;
 117         ualg->cru_refcnt = atomic_read(&alg->cra_refcnt);
 118
 119         NLA_PUT_U32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority);
 120
 121         if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
 122                 struct crypto_report_larval rl;
 123
 124                 snprintf(rl.type, CRYPTO_MAX_ALG_NAME, "%s", "larval");
 125
 126                 NLA_PUT(skb, CRYPTOCFGA_REPORT_LARVAL,
 127                         sizeof(struct crypto_report_larval), &rl);
 128
 129                 goto out;
 130         }
 131
 132         if (alg->cra_type && alg->cra_type->report) {
 133                 if (alg->cra_type->report(skb, alg))
 134                         goto nla_put_failure;
 135
 136                 goto out;
 137         }
 138
 139         switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
 140         case CRYPTO_ALG_TYPE_CIPHER:
 141                 if (crypto_report_cipher(skb, alg))
 142                         goto nla_put_failure;
 143
 144                 break;
 145         case CRYPTO_ALG_TYPE_COMPRESS:
 146                 if (crypto_report_comp(skb, alg))
 147                         goto nla_put_failure;
 148
 149                 break;
 150         }
 151
 152 out:
 153         return 0;
 154
 155 nla_put_failure:
 156         return -EMSGSIZE;
 157 }
 158
 159 static int crypto_report_alg(struct crypto_alg *alg,
 160                              struct crypto_dump_info *info)
 161 {
 162         struct sk_buff *in_skb = info->in_skb;
 163         struct sk_buff *skb = info->out_skb;
 164         struct nlmsghdr *nlh;
 165         struct crypto_user_alg *ualg;
 166         int err = 0;
 167
 168         nlh = nlmsg_put(skb, NETLINK_CB(in_skb).pid, info->nlmsg_seq,
 169                         CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
 170         if (!nlh) {
 171                 err = -EMSGSIZE;
 172                 goto out;
 173         }
 174
 175         ualg = nlmsg_data(nlh);
 176
 177         err = crypto_report_one(alg, ualg, skb);
 178         if (err) {
 179                 nlmsg_cancel(skb, nlh);
 180                 goto out;
 181         }
 182
 183         nlmsg_end(skb, nlh);
 184
 185 out:
 186         return err;
 187 }
 188
 189 static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
 190                          struct nlattr **attrs)
 191 {
 192         struct crypto_user_alg *p = nlmsg_data(in_nlh);
 193         struct crypto_alg *alg;
 194         struct sk_buff *skb;
 195         struct crypto_dump_info info;
 196         int err;
 197
 198         if (!p->cru_driver_name)
 199                 return -EINVAL;
 200
 201         alg = crypto_alg_match(p, 1);
 202         if (!alg)
 203                 return -ENOENT;
 204
 205         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
 206         if (!skb)
 207                 return -ENOMEM;
 208
 209         info.in_skb = in_skb;
 210         info.out_skb = skb;
 211         info.nlmsg_seq = in_nlh->nlmsg_seq;
 212         info.nlmsg_flags = 0;
 213
 214         err = crypto_report_alg(alg, &info);
 215         if (err)
 216                 return err;
 217
 218         return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).pid);
 219 }
 220
 221 static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
 222 {
 223         struct crypto_alg *alg;
 224         struct crypto_dump_info info;
 225         int err;
 226
 227         if (cb->args[0])
 228                 goto out;
 229
 230         cb->args[0] = 1;
 231
 232         info.in_skb = cb->skb;
 233         info.out_skb = skb;
 234         info.nlmsg_seq = cb->nlh->nlmsg_seq;
 235         info.nlmsg_flags = NLM_F_MULTI;
 236
 237         list_for_each_entry(alg, &crypto_alg_list, cra_list) {
 238                 err = crypto_report_alg(alg, &info);
 239                 if (err)
 240                         goto out_err;
 241         }
 242
 243 out:
 244         return skb->len;
 245 out_err:
 246         return err;
 247 }
 248
 249 static int crypto_dump_report_done(struct netlink_callback *cb)
 250 {
 251         return 0;
 252 }
 253
 254 static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 255                              struct nlattr **attrs)
 256 {
 257         struct crypto_alg *alg;
 258         struct crypto_user_alg *p = nlmsg_data(nlh);
 259         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 260         LIST_HEAD(list);
 261
 262         if (priority && !strlen(p->cru_driver_name))
 263                 return -EINVAL;
 264
 265         alg = crypto_alg_match(p, 1);
 266         if (!alg)
 267                 return -ENOENT;
 268
 269         down_write(&crypto_alg_sem);
 270
 271         crypto_remove_spawns(alg, &list, NULL);
 272
 273         if (priority)
 274                 alg->cra_priority = nla_get_u32(priority);
 275
 276         up_write(&crypto_alg_sem);
 277
 278         crypto_remove_final(&list);
 279
 280         return 0;
 281 }
 282
 283 static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 284                           struct nlattr **attrs)
 285 {
 286         struct crypto_alg *alg;
 287         struct crypto_user_alg *p = nlmsg_data(nlh);
 288
 289         alg = crypto_alg_match(p, 1);
 290         if (!alg)
 291                 return -ENOENT;
 292
 293         /* We can not unregister core algorithms such as aes-generic.
 294          * We would loose the reference in the crypto_alg_list to this algorithm
 295          * if we try to unregister. Unregistering such an algorithm without
 296          * removing the module is not possible, so we restrict to crypto
 297          * instances that are build from templates. */
 298         if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
 299                 return -EINVAL;
 300
 301         if (atomic_read(&alg->cra_refcnt) != 1)
 302                 return -EBUSY;
 303
 304         return crypto_unregister_alg(alg);
 305 }
 306
 307 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 308                           struct nlattr **attrs)
 309 {
 310         int exact;
 311         const char *name;
 312         struct crypto_alg *alg;
 313         struct crypto_user_alg *p = nlmsg_data(nlh);
 314         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 315
 316         if (strlen(p->cru_driver_name))
 317                 exact = 1;
 318
 319         if (priority && !exact)
 320                 return -EINVAL;
 321
 322         alg = crypto_alg_match(p, exact);
 323         if (alg)
 324                 return -EEXIST;
 325
 326         if (strlen(p->cru_driver_name))
 327                 name = p->cru_driver_name;
 328         else
 329                 name = p->cru_name;
 330
 331         alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
 332         if (IS_ERR(alg))
 333                 return PTR_ERR(alg);
 334
 335         down_write(&crypto_alg_sem);
 336
 337         if (priority)
 338                 alg->cra_priority = nla_get_u32(priority);
 339
 340         up_write(&crypto_alg_sem);
 341
 342         crypto_mod_put(alg);
 343
 344         return 0;
 345 }
 346
 347 #define MSGSIZE(type) sizeof(struct type)
 348
 349 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
 350         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 351         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 352         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 353         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 354 };
 355
 356 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
 357         [CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
 358 };
 359
 360 #undef MSGSIZE
 361
 362 static struct crypto_link {
 363         int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
 364         int (*dump)(struct sk_buff *, struct netlink_callback *);
 365         int (*done)(struct netlink_callback *);
 366 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
 367         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
 368         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
 369         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
 370         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = { .doit = crypto_report,
 371                                                        .dump = crypto_dump_report,
 372                                                        .done = crypto_dump_report_done},
 373 };
 374
 375 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 376 {
 377         struct nlattr *attrs[CRYPTOCFGA_MAX+1];
 378         struct crypto_link *link;
 379         int type, err;
 380
 381         type = nlh->nlmsg_type;
 382         if (type > CRYPTO_MSG_MAX)
 383                 return -EINVAL;
 384
 385         type -= CRYPTO_MSG_BASE;
 386         link = &crypto_dispatch[type];
 387
 388         if (security_netlink_recv(skb, CAP_NET_ADMIN))
 389                 return -EPERM;
 390
 391         if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
 392             (nlh->nlmsg_flags & NLM_F_DUMP))) {
 393                 if (link->dump == NULL)
 394                         return -EINVAL;
 395
 396                 return netlink_dump_start(crypto_nlsk, skb, nlh,
 397                                           link->dump, link->done, 0);
 398         }
 399
 400         err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
 401                           crypto_policy);
 402         if (err < 0)
 403                 return err;
 404
 405         if (link->doit == NULL)
 406                 return -EINVAL;
 407
 408         return link->doit(skb, nlh, attrs);
 409 }
 410
 411 static void crypto_netlink_rcv(struct sk_buff *skb)
 412 {
 413         mutex_lock(&crypto_cfg_mutex);
 414         netlink_rcv_skb(skb, &crypto_user_rcv_msg);
 415         mutex_unlock(&crypto_cfg_mutex);
 416 }
 417
 418 static int __init crypto_user_init(void)
 419 {
 420         crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO,
 421                                             0, crypto_netlink_rcv,
 422                                             NULL, THIS_MODULE);
 423         if (!crypto_nlsk)
 424                 return -ENOMEM;
 425
 426         return 0;
 427 }
 428
 429 static void __exit crypto_user_exit(void)
 430 {
 431         netlink_kernel_release(crypto_nlsk);
 432 }
 433
 434 module_init(crypto_user_init);
 435 module_exit(crypto_user_exit);
 436 MODULE_LICENSE("GPL");
 437 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 438 MODULE_DESCRIPTION("Crypto userspace configuration API");