linux/crypto/crypto_user.c
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   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
  32#include "internal.h"
  33
  34#define null_terminated(x)      (strnlen(x, sizeof(x)) < sizeof(x))
  35
  36static DEFINE_MUTEX(crypto_cfg_mutex);
  37
  38/* The crypto netlink socket */
  39static struct sock *crypto_nlsk;
  40
  41struct crypto_dump_info {
  42        struct sk_buff *in_skb;
  43        struct sk_buff *out_skb;
  44        u32 nlmsg_seq;
  45        u16 nlmsg_flags;
  46};
  47
  48static struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
  49{
  50        struct crypto_alg *q, *alg = NULL;
  51
  52        down_read(&crypto_alg_sem);
  53
  54        list_for_each_entry(q, &crypto_alg_list, cra_list) {
  55                int match = 0;
  56
  57                if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
  58                        continue;
  59
  60                if (strlen(p->cru_driver_name))
  61                        match = !strcmp(q->cra_driver_name,
  62                                        p->cru_driver_name);
  63                else if (!exact)
  64                        match = !strcmp(q->cra_name, p->cru_name);
  65
  66                if (!match)
  67                        continue;
  68
  69                if (unlikely(!crypto_mod_get(q)))
  70                        continue;
  71
  72                alg = q;
  73                break;
  74        }
  75
  76        up_read(&crypto_alg_sem);
  77
  78        return alg;
  79}
  80
  81static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
  82{
  83        struct crypto_report_cipher rcipher;
  84
  85        strncpy(rcipher.type, "cipher", sizeof(rcipher.type));
  86
  87        rcipher.blocksize = alg->cra_blocksize;
  88        rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
  89        rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
  90
  91        if (nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
  92                    sizeof(struct crypto_report_cipher), &rcipher))
  93                goto nla_put_failure;
  94        return 0;
  95
  96nla_put_failure:
  97        return -EMSGSIZE;
  98}
  99
 100static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
 101{
 102        struct crypto_report_comp rcomp;
 103
 104        strncpy(rcomp.type, "compression", sizeof(rcomp.type));
 105        if (nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS,
 106                    sizeof(struct crypto_report_comp), &rcomp))
 107                goto nla_put_failure;
 108        return 0;
 109
 110nla_put_failure:
 111        return -EMSGSIZE;
 112}
 113
 114static int crypto_report_akcipher(struct sk_buff *skb, struct crypto_alg *alg)
 115{
 116        struct crypto_report_akcipher rakcipher;
 117
 118        strncpy(rakcipher.type, "akcipher", sizeof(rakcipher.type));
 119
 120        if (nla_put(skb, CRYPTOCFGA_REPORT_AKCIPHER,
 121                    sizeof(struct crypto_report_akcipher), &rakcipher))
 122                goto nla_put_failure;
 123        return 0;
 124
 125nla_put_failure:
 126        return -EMSGSIZE;
 127}
 128
 129static int crypto_report_one(struct crypto_alg *alg,
 130                             struct crypto_user_alg *ualg, struct sk_buff *skb)
 131{
 132        strncpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
 133        strncpy(ualg->cru_driver_name, alg->cra_driver_name,
 134                sizeof(ualg->cru_driver_name));
 135        strncpy(ualg->cru_module_name, module_name(alg->cra_module),
 136                sizeof(ualg->cru_module_name));
 137
 138        ualg->cru_type = 0;
 139        ualg->cru_mask = 0;
 140        ualg->cru_flags = alg->cra_flags;
 141        ualg->cru_refcnt = atomic_read(&alg->cra_refcnt);
 142
 143        if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
 144                goto nla_put_failure;
 145        if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
 146                struct crypto_report_larval rl;
 147
 148                strncpy(rl.type, "larval", sizeof(rl.type));
 149                if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL,
 150                            sizeof(struct crypto_report_larval), &rl))
 151                        goto nla_put_failure;
 152                goto out;
 153        }
 154
 155        if (alg->cra_type && alg->cra_type->report) {
 156                if (alg->cra_type->report(skb, alg))
 157                        goto nla_put_failure;
 158
 159                goto out;
 160        }
 161
 162        switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
 163        case CRYPTO_ALG_TYPE_CIPHER:
 164                if (crypto_report_cipher(skb, alg))
 165                        goto nla_put_failure;
 166
 167                break;
 168        case CRYPTO_ALG_TYPE_COMPRESS:
 169                if (crypto_report_comp(skb, alg))
 170                        goto nla_put_failure;
 171
 172                break;
 173
 174        case CRYPTO_ALG_TYPE_AKCIPHER:
 175                if (crypto_report_akcipher(skb, alg))
 176                        goto nla_put_failure;
 177
 178                break;
 179        }
 180
 181out:
 182        return 0;
 183
 184nla_put_failure:
 185        return -EMSGSIZE;
 186}
 187
 188static int crypto_report_alg(struct crypto_alg *alg,
 189                             struct crypto_dump_info *info)
 190{
 191        struct sk_buff *in_skb = info->in_skb;
 192        struct sk_buff *skb = info->out_skb;
 193        struct nlmsghdr *nlh;
 194        struct crypto_user_alg *ualg;
 195        int err = 0;
 196
 197        nlh = nlmsg_put(skb, NETLINK_CB(in_skb).portid, info->nlmsg_seq,
 198                        CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
 199        if (!nlh) {
 200                err = -EMSGSIZE;
 201                goto out;
 202        }
 203
 204        ualg = nlmsg_data(nlh);
 205
 206        err = crypto_report_one(alg, ualg, skb);
 207        if (err) {
 208                nlmsg_cancel(skb, nlh);
 209                goto out;
 210        }
 211
 212        nlmsg_end(skb, nlh);
 213
 214out:
 215        return err;
 216}
 217
 218static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
 219                         struct nlattr **attrs)
 220{
 221        struct crypto_user_alg *p = nlmsg_data(in_nlh);
 222        struct crypto_alg *alg;
 223        struct sk_buff *skb;
 224        struct crypto_dump_info info;
 225        int err;
 226
 227        if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 228                return -EINVAL;
 229
 230        alg = crypto_alg_match(p, 0);
 231        if (!alg)
 232                return -ENOENT;
 233
 234        err = -ENOMEM;
 235        skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
 236        if (!skb)
 237                goto drop_alg;
 238
 239        info.in_skb = in_skb;
 240        info.out_skb = skb;
 241        info.nlmsg_seq = in_nlh->nlmsg_seq;
 242        info.nlmsg_flags = 0;
 243
 244        err = crypto_report_alg(alg, &info);
 245
 246drop_alg:
 247        crypto_mod_put(alg);
 248
 249        if (err)
 250                return err;
 251
 252        return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
 253}
 254
 255static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
 256{
 257        struct crypto_alg *alg;
 258        struct crypto_dump_info info;
 259        int err;
 260
 261        if (cb->args[0])
 262                goto out;
 263
 264        cb->args[0] = 1;
 265
 266        info.in_skb = cb->skb;
 267        info.out_skb = skb;
 268        info.nlmsg_seq = cb->nlh->nlmsg_seq;
 269        info.nlmsg_flags = NLM_F_MULTI;
 270
 271        list_for_each_entry(alg, &crypto_alg_list, cra_list) {
 272                err = crypto_report_alg(alg, &info);
 273                if (err)
 274                        goto out_err;
 275        }
 276
 277out:
 278        return skb->len;
 279out_err:
 280        return err;
 281}
 282
 283static int crypto_dump_report_done(struct netlink_callback *cb)
 284{
 285        return 0;
 286}
 287
 288static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 289                             struct nlattr **attrs)
 290{
 291        struct crypto_alg *alg;
 292        struct crypto_user_alg *p = nlmsg_data(nlh);
 293        struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 294        LIST_HEAD(list);
 295
 296        if (!netlink_capable(skb, CAP_NET_ADMIN))
 297                return -EPERM;
 298
 299        if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 300                return -EINVAL;
 301
 302        if (priority && !strlen(p->cru_driver_name))
 303                return -EINVAL;
 304
 305        alg = crypto_alg_match(p, 1);
 306        if (!alg)
 307                return -ENOENT;
 308
 309        down_write(&crypto_alg_sem);
 310
 311        crypto_remove_spawns(alg, &list, NULL);
 312
 313        if (priority)
 314                alg->cra_priority = nla_get_u32(priority);
 315
 316        up_write(&crypto_alg_sem);
 317
 318        crypto_mod_put(alg);
 319        crypto_remove_final(&list);
 320
 321        return 0;
 322}
 323
 324static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 325                          struct nlattr **attrs)
 326{
 327        struct crypto_alg *alg;
 328        struct crypto_user_alg *p = nlmsg_data(nlh);
 329        int err;
 330
 331        if (!netlink_capable(skb, CAP_NET_ADMIN))
 332                return -EPERM;
 333
 334        if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 335                return -EINVAL;
 336
 337        alg = crypto_alg_match(p, 1);
 338        if (!alg)
 339                return -ENOENT;
 340
 341        /* We can not unregister core algorithms such as aes-generic.
 342         * We would loose the reference in the crypto_alg_list to this algorithm
 343         * if we try to unregister. Unregistering such an algorithm without
 344         * removing the module is not possible, so we restrict to crypto
 345         * instances that are build from templates. */
 346        err = -EINVAL;
 347        if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
 348                goto drop_alg;
 349
 350        err = -EBUSY;
 351        if (atomic_read(&alg->cra_refcnt) > 2)
 352                goto drop_alg;
 353
 354        err = crypto_unregister_instance((struct crypto_instance *)alg);
 355
 356drop_alg:
 357        crypto_mod_put(alg);
 358        return err;
 359}
 360
 361static struct crypto_alg *crypto_user_skcipher_alg(const char *name, u32 type,
 362                                                   u32 mask)
 363{
 364        int err;
 365        struct crypto_alg *alg;
 366
 367        type = crypto_skcipher_type(type);
 368        mask = crypto_skcipher_mask(mask);
 369
 370        for (;;) {
 371                alg = crypto_lookup_skcipher(name,  type, mask);
 372                if (!IS_ERR(alg))
 373                        return alg;
 374
 375                err = PTR_ERR(alg);
 376                if (err != -EAGAIN)
 377                        break;
 378                if (fatal_signal_pending(current)) {
 379                        err = -EINTR;
 380                        break;
 381                }
 382        }
 383
 384        return ERR_PTR(err);
 385}
 386
 387static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 388                          struct nlattr **attrs)
 389{
 390        int exact = 0;
 391        const char *name;
 392        struct crypto_alg *alg;
 393        struct crypto_user_alg *p = nlmsg_data(nlh);
 394        struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 395
 396        if (!netlink_capable(skb, CAP_NET_ADMIN))
 397                return -EPERM;
 398
 399        if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 400                return -EINVAL;
 401
 402        if (strlen(p->cru_driver_name))
 403                exact = 1;
 404
 405        if (priority && !exact)
 406                return -EINVAL;
 407
 408        alg = crypto_alg_match(p, exact);
 409        if (alg) {
 410                crypto_mod_put(alg);
 411                return -EEXIST;
 412        }
 413
 414        if (strlen(p->cru_driver_name))
 415                name = p->cru_driver_name;
 416        else
 417                name = p->cru_name;
 418
 419        switch (p->cru_type & p->cru_mask & CRYPTO_ALG_TYPE_MASK) {
 420        case CRYPTO_ALG_TYPE_GIVCIPHER:
 421        case CRYPTO_ALG_TYPE_BLKCIPHER:
 422        case CRYPTO_ALG_TYPE_ABLKCIPHER:
 423                alg = crypto_user_skcipher_alg(name, p->cru_type, p->cru_mask);
 424                break;
 425        default:
 426                alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
 427        }
 428
 429        if (IS_ERR(alg))
 430                return PTR_ERR(alg);
 431
 432        down_write(&crypto_alg_sem);
 433
 434        if (priority)
 435                alg->cra_priority = nla_get_u32(priority);
 436
 437        up_write(&crypto_alg_sem);
 438
 439        crypto_mod_put(alg);
 440
 441        return 0;
 442}
 443
 444static int crypto_del_rng(struct sk_buff *skb, struct nlmsghdr *nlh,
 445                          struct nlattr **attrs)
 446{
 447        if (!netlink_capable(skb, CAP_NET_ADMIN))
 448                return -EPERM;
 449        return crypto_del_default_rng();
 450}
 451
 452#define MSGSIZE(type) sizeof(struct type)
 453
 454static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
 455        [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 456        [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 457        [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 458        [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = 0,
 459};
 460
 461static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
 462        [CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
 463};
 464
 465#undef MSGSIZE
 466
 467static const struct crypto_link {
 468        int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
 469        int (*dump)(struct sk_buff *, struct netlink_callback *);
 470        int (*done)(struct netlink_callback *);
 471} crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
 472        [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
 473        [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
 474        [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
 475        [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = { .doit = crypto_report,
 476                                                       .dump = crypto_dump_report,
 477                                                       .done = crypto_dump_report_done},
 478        [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_rng },
 479};
 480
 481static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
 482{
 483        struct nlattr *attrs[CRYPTOCFGA_MAX+1];
 484        const struct crypto_link *link;
 485        int type, err;
 486
 487        type = nlh->nlmsg_type;
 488        if (type > CRYPTO_MSG_MAX)
 489                return -EINVAL;
 490
 491        type -= CRYPTO_MSG_BASE;
 492        link = &crypto_dispatch[type];
 493
 494        if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
 495            (nlh->nlmsg_flags & NLM_F_DUMP))) {
 496                struct crypto_alg *alg;
 497                u16 dump_alloc = 0;
 498
 499                if (link->dump == NULL)
 500                        return -EINVAL;
 501
 502                down_read(&crypto_alg_sem);
 503                list_for_each_entry(alg, &crypto_alg_list, cra_list)
 504                        dump_alloc += CRYPTO_REPORT_MAXSIZE;
 505
 506                {
 507                        struct netlink_dump_control c = {
 508                                .dump = link->dump,
 509                                .done = link->done,
 510                                .min_dump_alloc = dump_alloc,
 511                        };
 512                        err = netlink_dump_start(crypto_nlsk, skb, nlh, &c);
 513                }
 514                up_read(&crypto_alg_sem);
 515
 516                return err;
 517        }
 518
 519        err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
 520                          crypto_policy);
 521        if (err < 0)
 522                return err;
 523
 524        if (link->doit == NULL)
 525                return -EINVAL;
 526
 527        return link->doit(skb, nlh, attrs);
 528}
 529
 530static void crypto_netlink_rcv(struct sk_buff *skb)
 531{
 532        mutex_lock(&crypto_cfg_mutex);
 533        netlink_rcv_skb(skb, &crypto_user_rcv_msg);
 534        mutex_unlock(&crypto_cfg_mutex);
 535}
 536
 537static int __init crypto_user_init(void)
 538{
 539        struct netlink_kernel_cfg cfg = {
 540                .input  = crypto_netlink_rcv,
 541        };
 542
 543        crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO, &cfg);
 544        if (!crypto_nlsk)
 545                return -ENOMEM;
 546
 547        return 0;
 548}
 549
 550static void __exit crypto_user_exit(void)
 551{
 552        netlink_kernel_release(crypto_nlsk);
 553}
 554
 555module_init(crypto_user_init);
 556module_exit(crypto_user_exit);
 557MODULE_LICENSE("GPL");
 558MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 559MODULE_DESCRIPTION("Crypto userspace configuration API");
 560MODULE_ALIAS("net-pf-16-proto-21");
 561