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