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         list_for_each_entry(q, &crypto_alg_list, cra_list) {
  48                 int match = 0;
  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                         alg = q;
  61                         break;
  62                 }
  63         }
  64
  65         up_read(&crypto_alg_sem);
  66
  67         return alg;
  68 }
  69
  70 static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
  71 {
  72         struct crypto_report_cipher rcipher;
  73
  74         strncpy(rcipher.type, "cipher", sizeof(rcipher.type));
  75
  76         rcipher.blocksize = alg->cra_blocksize;
  77         rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
  78         rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
  79
  80         NLA_PUT(skb, CRYPTOCFGA_REPORT_CIPHER,
  81                 sizeof(struct crypto_report_cipher), &rcipher);
  82
  83         return 0;
  84
  85 nla_put_failure:
  86         return -EMSGSIZE;
  87 }
  88
  89 static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
  90 {
  91         struct crypto_report_comp rcomp;
  92
  93         strncpy(rcomp.type, "compression", sizeof(rcomp.type));
  94         NLA_PUT(skb, CRYPTOCFGA_REPORT_COMPRESS,
  95                 sizeof(struct crypto_report_comp), &rcomp);
  96
  97         return 0;
  98
  99 nla_put_failure:
 100         return -EMSGSIZE;
 101 }
 102
 103 static int crypto_report_one(struct crypto_alg *alg,
 104                              struct crypto_user_alg *ualg, struct sk_buff *skb)
 105 {
 106         strncpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
 107         strncpy(ualg->cru_driver_name, alg->cra_driver_name,
 108                 sizeof(ualg->cru_driver_name));
 109         strncpy(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 = atomic_read(&alg->cra_refcnt);
 116
 117         NLA_PUT_U32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority);
 118
 119         if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
 120                 struct crypto_report_larval rl;
 121
 122                 strncpy(rl.type, "larval", sizeof(rl.type));
 123                 NLA_PUT(skb, CRYPTOCFGA_REPORT_LARVAL,
 124                         sizeof(struct crypto_report_larval), &rl);
 125
 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).pid, 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 (!p->cru_driver_name)
 196                 return -EINVAL;
 197
 198         alg = crypto_alg_match(p, 1);
 199         if (!alg)
 200                 return -ENOENT;
 201
 202         skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
 203         if (!skb)
 204                 return -ENOMEM;
 205
 206         info.in_skb = in_skb;
 207         info.out_skb = skb;
 208         info.nlmsg_seq = in_nlh->nlmsg_seq;
 209         info.nlmsg_flags = 0;
 210
 211         err = crypto_report_alg(alg, &info);
 212         if (err)
 213                 return err;
 214
 215         return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).pid);
 216 }
 217
 218 static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
 219 {
 220         struct crypto_alg *alg;
 221         struct crypto_dump_info info;
 222         int err;
 223
 224         if (cb->args[0])
 225                 goto out;
 226
 227         cb->args[0] = 1;
 228
 229         info.in_skb = cb->skb;
 230         info.out_skb = skb;
 231         info.nlmsg_seq = cb->nlh->nlmsg_seq;
 232         info.nlmsg_flags = NLM_F_MULTI;
 233
 234         list_for_each_entry(alg, &crypto_alg_list, cra_list) {
 235                 err = crypto_report_alg(alg, &info);
 236                 if (err)
 237                         goto out_err;
 238         }
 239
 240 out:
 241         return skb->len;
 242 out_err:
 243         return err;
 244 }
 245
 246 static int crypto_dump_report_done(struct netlink_callback *cb)
 247 {
 248         return 0;
 249 }
 250
 251 static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 252                              struct nlattr **attrs)
 253 {
 254         struct crypto_alg *alg;
 255         struct crypto_user_alg *p = nlmsg_data(nlh);
 256         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 257         LIST_HEAD(list);
 258
 259         if (priority && !strlen(p->cru_driver_name))
 260                 return -EINVAL;
 261
 262         alg = crypto_alg_match(p, 1);
 263         if (!alg)
 264                 return -ENOENT;
 265
 266         down_write(&crypto_alg_sem);
 267
 268         crypto_remove_spawns(alg, &list, NULL);
 269
 270         if (priority)
 271                 alg->cra_priority = nla_get_u32(priority);
 272
 273         up_write(&crypto_alg_sem);
 274
 275         crypto_remove_final(&list);
 276
 277         return 0;
 278 }
 279
 280 static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 281                           struct nlattr **attrs)
 282 {
 283         struct crypto_alg *alg;
 284         struct crypto_user_alg *p = nlmsg_data(nlh);
 285
 286         alg = crypto_alg_match(p, 1);
 287         if (!alg)
 288                 return -ENOENT;
 289
 290         /* We can not unregister core algorithms such as aes-generic.
 291          * We would loose the reference in the crypto_alg_list to this algorithm
 292          * if we try to unregister. Unregistering such an algorithm without
 293          * removing the module is not possible, so we restrict to crypto
 294          * instances that are build from templates. */
 295         if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
 296                 return -EINVAL;
 297
 298         if (atomic_read(&alg->cra_refcnt) != 1)
 299                 return -EBUSY;
 300
 301         return crypto_unregister_alg(alg);
 302 }
 303
 304 static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 305                           struct nlattr **attrs)
 306 {
 307         int exact;
 308         const char *name;
 309         struct crypto_alg *alg;
 310         struct crypto_user_alg *p = nlmsg_data(nlh);
 311         struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 312
 313         if (strlen(p->cru_driver_name))
 314                 exact = 1;
 315
 316         if (priority && !exact)
 317                 return -EINVAL;
 318
 319         alg = crypto_alg_match(p, exact);
 320         if (alg)
 321                 return -EEXIST;
 322
 323         if (strlen(p->cru_driver_name))
 324                 name = p->cru_driver_name;
 325         else
 326                 name = p->cru_name;
 327
 328         alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
 329         if (IS_ERR(alg))
 330                 return PTR_ERR(alg);
 331
 332         down_write(&crypto_alg_sem);
 333
 334         if (priority)
 335                 alg->cra_priority = nla_get_u32(priority);
 336
 337         up_write(&crypto_alg_sem);
 338
 339         crypto_mod_put(alg);
 340
 341         return 0;
 342 }
 343
 344 #define MSGSIZE(type) sizeof(struct type)
 345
 346 static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
 347         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 348         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 349         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 350         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 351 };
 352
 353 static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
 354         [CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
 355 };
 356
 357 #undef MSGSIZE
 358
 359 static struct crypto_link {
 360         int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
 361         int (*dump)(struct sk_buff *, struct netlink_callback *);
 362         int (*done)(struct netlink_callback *);
 363 } crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
 364         [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
 365         [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
 366         [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
 367         [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = { .doit = crypto_report,
 368                                                        .dump = crypto_dump_report,
 369                                                        .done = crypto_dump_report_done},
 370 };
 371
 372 static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 373 {
 374         struct nlattr *attrs[CRYPTOCFGA_MAX+1];
 375         struct crypto_link *link;
 376         int type, err;
 377
 378         type = nlh->nlmsg_type;
 379         if (type > CRYPTO_MSG_MAX)
 380                 return -EINVAL;
 381
 382         type -= CRYPTO_MSG_BASE;
 383         link = &crypto_dispatch[type];
 384
 385         if (security_netlink_recv(skb, CAP_NET_ADMIN))
 386                 return -EPERM;
 387
 388         if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
 389             (nlh->nlmsg_flags & NLM_F_DUMP))) {
 390                 if (link->dump == NULL)
 391                         return -EINVAL;
 392
 393                 return netlink_dump_start(crypto_nlsk, skb, nlh,
 394                                           link->dump, link->done, 0);
 395         }
 396
 397         err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
 398                           crypto_policy);
 399         if (err < 0)
 400                 return err;
 401
 402         if (link->doit == NULL)
 403                 return -EINVAL;
 404
 405         return link->doit(skb, nlh, attrs);
 406 }
 407
 408 static void crypto_netlink_rcv(struct sk_buff *skb)
 409 {
 410         mutex_lock(&crypto_cfg_mutex);
 411         netlink_rcv_skb(skb, &crypto_user_rcv_msg);
 412         mutex_unlock(&crypto_cfg_mutex);
 413 }
 414
 415 static int __init crypto_user_init(void)
 416 {
 417         crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO,
 418                                             0, crypto_netlink_rcv,
 419                                             NULL, THIS_MODULE);
 420         if (!crypto_nlsk)
 421                 return -ENOMEM;
 422
 423         return 0;
 424 }
 425
 426 static void __exit crypto_user_exit(void)
 427 {
 428         netlink_kernel_release(crypto_nlsk);
 429 }
 430
 431 module_init(crypto_user_init);
 432 module_exit(crypto_user_exit);
 433 MODULE_LICENSE("GPL");
 434 MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 435 MODULE_DESCRIPTION("Crypto userspace configuration API");