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#include <crypto/kpp.h>
  32
  33#include "internal.h"
  34
  35#define null_terminated(x)      (strnlen(x, sizeof(x)) < sizeof(x))
  36
  37static DEFINE_MUTEX(crypto_cfg_mutex);
  38
  39/* The crypto netlink socket */
  40static struct sock *crypto_nlsk;
  41
  42struct crypto_dump_info {
  43        struct sk_buff *in_skb;
  44        struct sk_buff *out_skb;
  45        u32 nlmsg_seq;
  46        u16 nlmsg_flags;
  47};
  48
  49static struct crypto_alg *crypto_alg_match(struct crypto_user_alg *p, int exact)
  50{
  51        struct crypto_alg *q, *alg = NULL;
  52
  53        down_read(&crypto_alg_sem);
  54
  55        list_for_each_entry(q, &crypto_alg_list, cra_list) {
  56                int match = 0;
  57
  58                if ((q->cra_flags ^ p->cru_type) & p->cru_mask)
  59                        continue;
  60
  61                if (strlen(p->cru_driver_name))
  62                        match = !strcmp(q->cra_driver_name,
  63                                        p->cru_driver_name);
  64                else if (!exact)
  65                        match = !strcmp(q->cra_name, p->cru_name);
  66
  67                if (!match)
  68                        continue;
  69
  70                if (unlikely(!crypto_mod_get(q)))
  71                        continue;
  72
  73                alg = q;
  74                break;
  75        }
  76
  77        up_read(&crypto_alg_sem);
  78
  79        return alg;
  80}
  81
  82static int crypto_report_cipher(struct sk_buff *skb, struct crypto_alg *alg)
  83{
  84        struct crypto_report_cipher rcipher;
  85
  86        strlcpy(rcipher.type, "cipher", sizeof(rcipher.type));
  87
  88        rcipher.blocksize = alg->cra_blocksize;
  89        rcipher.min_keysize = alg->cra_cipher.cia_min_keysize;
  90        rcipher.max_keysize = alg->cra_cipher.cia_max_keysize;
  91
  92        if (nla_put(skb, CRYPTOCFGA_REPORT_CIPHER,
  93                    sizeof(struct crypto_report_cipher), &rcipher))
  94                goto nla_put_failure;
  95        return 0;
  96
  97nla_put_failure:
  98        return -EMSGSIZE;
  99}
 100
 101static int crypto_report_comp(struct sk_buff *skb, struct crypto_alg *alg)
 102{
 103        struct crypto_report_comp rcomp;
 104
 105        strlcpy(rcomp.type, "compression", sizeof(rcomp.type));
 106        if (nla_put(skb, CRYPTOCFGA_REPORT_COMPRESS,
 107                    sizeof(struct crypto_report_comp), &rcomp))
 108                goto nla_put_failure;
 109        return 0;
 110
 111nla_put_failure:
 112        return -EMSGSIZE;
 113}
 114
 115static int crypto_report_acomp(struct sk_buff *skb, struct crypto_alg *alg)
 116{
 117        struct crypto_report_acomp racomp;
 118
 119        strlcpy(racomp.type, "acomp", sizeof(racomp.type));
 120
 121        if (nla_put(skb, CRYPTOCFGA_REPORT_ACOMP,
 122                    sizeof(struct crypto_report_acomp), &racomp))
 123                goto nla_put_failure;
 124        return 0;
 125
 126nla_put_failure:
 127        return -EMSGSIZE;
 128}
 129
 130static int crypto_report_akcipher(struct sk_buff *skb, struct crypto_alg *alg)
 131{
 132        struct crypto_report_akcipher rakcipher;
 133
 134        strlcpy(rakcipher.type, "akcipher", sizeof(rakcipher.type));
 135
 136        if (nla_put(skb, CRYPTOCFGA_REPORT_AKCIPHER,
 137                    sizeof(struct crypto_report_akcipher), &rakcipher))
 138                goto nla_put_failure;
 139        return 0;
 140
 141nla_put_failure:
 142        return -EMSGSIZE;
 143}
 144
 145static int crypto_report_kpp(struct sk_buff *skb, struct crypto_alg *alg)
 146{
 147        struct crypto_report_kpp rkpp;
 148
 149        strlcpy(rkpp.type, "kpp", sizeof(rkpp.type));
 150
 151        if (nla_put(skb, CRYPTOCFGA_REPORT_KPP,
 152                    sizeof(struct crypto_report_kpp), &rkpp))
 153                goto nla_put_failure;
 154        return 0;
 155
 156nla_put_failure:
 157        return -EMSGSIZE;
 158}
 159
 160static int crypto_report_one(struct crypto_alg *alg,
 161                             struct crypto_user_alg *ualg, struct sk_buff *skb)
 162{
 163        strlcpy(ualg->cru_name, alg->cra_name, sizeof(ualg->cru_name));
 164        strlcpy(ualg->cru_driver_name, alg->cra_driver_name,
 165                sizeof(ualg->cru_driver_name));
 166        strlcpy(ualg->cru_module_name, module_name(alg->cra_module),
 167                sizeof(ualg->cru_module_name));
 168
 169        ualg->cru_type = 0;
 170        ualg->cru_mask = 0;
 171        ualg->cru_flags = alg->cra_flags;
 172        ualg->cru_refcnt = refcount_read(&alg->cra_refcnt);
 173
 174        if (nla_put_u32(skb, CRYPTOCFGA_PRIORITY_VAL, alg->cra_priority))
 175                goto nla_put_failure;
 176        if (alg->cra_flags & CRYPTO_ALG_LARVAL) {
 177                struct crypto_report_larval rl;
 178
 179                strlcpy(rl.type, "larval", sizeof(rl.type));
 180                if (nla_put(skb, CRYPTOCFGA_REPORT_LARVAL,
 181                            sizeof(struct crypto_report_larval), &rl))
 182                        goto nla_put_failure;
 183                goto out;
 184        }
 185
 186        if (alg->cra_type && alg->cra_type->report) {
 187                if (alg->cra_type->report(skb, alg))
 188                        goto nla_put_failure;
 189
 190                goto out;
 191        }
 192
 193        switch (alg->cra_flags & (CRYPTO_ALG_TYPE_MASK | CRYPTO_ALG_LARVAL)) {
 194        case CRYPTO_ALG_TYPE_CIPHER:
 195                if (crypto_report_cipher(skb, alg))
 196                        goto nla_put_failure;
 197
 198                break;
 199        case CRYPTO_ALG_TYPE_COMPRESS:
 200                if (crypto_report_comp(skb, alg))
 201                        goto nla_put_failure;
 202
 203                break;
 204        case CRYPTO_ALG_TYPE_ACOMPRESS:
 205                if (crypto_report_acomp(skb, alg))
 206                        goto nla_put_failure;
 207
 208                break;
 209        case CRYPTO_ALG_TYPE_AKCIPHER:
 210                if (crypto_report_akcipher(skb, alg))
 211                        goto nla_put_failure;
 212
 213                break;
 214        case CRYPTO_ALG_TYPE_KPP:
 215                if (crypto_report_kpp(skb, alg))
 216                        goto nla_put_failure;
 217                break;
 218        }
 219
 220out:
 221        return 0;
 222
 223nla_put_failure:
 224        return -EMSGSIZE;
 225}
 226
 227static int crypto_report_alg(struct crypto_alg *alg,
 228                             struct crypto_dump_info *info)
 229{
 230        struct sk_buff *in_skb = info->in_skb;
 231        struct sk_buff *skb = info->out_skb;
 232        struct nlmsghdr *nlh;
 233        struct crypto_user_alg *ualg;
 234        int err = 0;
 235
 236        nlh = nlmsg_put(skb, NETLINK_CB(in_skb).portid, info->nlmsg_seq,
 237                        CRYPTO_MSG_GETALG, sizeof(*ualg), info->nlmsg_flags);
 238        if (!nlh) {
 239                err = -EMSGSIZE;
 240                goto out;
 241        }
 242
 243        ualg = nlmsg_data(nlh);
 244
 245        err = crypto_report_one(alg, ualg, skb);
 246        if (err) {
 247                nlmsg_cancel(skb, nlh);
 248                goto out;
 249        }
 250
 251        nlmsg_end(skb, nlh);
 252
 253out:
 254        return err;
 255}
 256
 257static int crypto_report(struct sk_buff *in_skb, struct nlmsghdr *in_nlh,
 258                         struct nlattr **attrs)
 259{
 260        struct crypto_user_alg *p = nlmsg_data(in_nlh);
 261        struct crypto_alg *alg;
 262        struct sk_buff *skb;
 263        struct crypto_dump_info info;
 264        int err;
 265
 266        if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 267                return -EINVAL;
 268
 269        alg = crypto_alg_match(p, 0);
 270        if (!alg)
 271                return -ENOENT;
 272
 273        err = -ENOMEM;
 274        skb = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
 275        if (!skb)
 276                goto drop_alg;
 277
 278        info.in_skb = in_skb;
 279        info.out_skb = skb;
 280        info.nlmsg_seq = in_nlh->nlmsg_seq;
 281        info.nlmsg_flags = 0;
 282
 283        err = crypto_report_alg(alg, &info);
 284
 285drop_alg:
 286        crypto_mod_put(alg);
 287
 288        if (err)
 289                return err;
 290
 291        return nlmsg_unicast(crypto_nlsk, skb, NETLINK_CB(in_skb).portid);
 292}
 293
 294static int crypto_dump_report(struct sk_buff *skb, struct netlink_callback *cb)
 295{
 296        struct crypto_alg *alg;
 297        struct crypto_dump_info info;
 298        int err;
 299
 300        if (cb->args[0])
 301                goto out;
 302
 303        cb->args[0] = 1;
 304
 305        info.in_skb = cb->skb;
 306        info.out_skb = skb;
 307        info.nlmsg_seq = cb->nlh->nlmsg_seq;
 308        info.nlmsg_flags = NLM_F_MULTI;
 309
 310        list_for_each_entry(alg, &crypto_alg_list, cra_list) {
 311                err = crypto_report_alg(alg, &info);
 312                if (err)
 313                        goto out_err;
 314        }
 315
 316out:
 317        return skb->len;
 318out_err:
 319        return err;
 320}
 321
 322static int crypto_dump_report_done(struct netlink_callback *cb)
 323{
 324        return 0;
 325}
 326
 327static int crypto_update_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 328                             struct nlattr **attrs)
 329{
 330        struct crypto_alg *alg;
 331        struct crypto_user_alg *p = nlmsg_data(nlh);
 332        struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 333        LIST_HEAD(list);
 334
 335        if (!netlink_capable(skb, CAP_NET_ADMIN))
 336                return -EPERM;
 337
 338        if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 339                return -EINVAL;
 340
 341        if (priority && !strlen(p->cru_driver_name))
 342                return -EINVAL;
 343
 344        alg = crypto_alg_match(p, 1);
 345        if (!alg)
 346                return -ENOENT;
 347
 348        down_write(&crypto_alg_sem);
 349
 350        crypto_remove_spawns(alg, &list, NULL);
 351
 352        if (priority)
 353                alg->cra_priority = nla_get_u32(priority);
 354
 355        up_write(&crypto_alg_sem);
 356
 357        crypto_mod_put(alg);
 358        crypto_remove_final(&list);
 359
 360        return 0;
 361}
 362
 363static int crypto_del_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 364                          struct nlattr **attrs)
 365{
 366        struct crypto_alg *alg;
 367        struct crypto_user_alg *p = nlmsg_data(nlh);
 368        int err;
 369
 370        if (!netlink_capable(skb, CAP_NET_ADMIN))
 371                return -EPERM;
 372
 373        if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 374                return -EINVAL;
 375
 376        alg = crypto_alg_match(p, 1);
 377        if (!alg)
 378                return -ENOENT;
 379
 380        /* We can not unregister core algorithms such as aes-generic.
 381         * We would loose the reference in the crypto_alg_list to this algorithm
 382         * if we try to unregister. Unregistering such an algorithm without
 383         * removing the module is not possible, so we restrict to crypto
 384         * instances that are build from templates. */
 385        err = -EINVAL;
 386        if (!(alg->cra_flags & CRYPTO_ALG_INSTANCE))
 387                goto drop_alg;
 388
 389        err = -EBUSY;
 390        if (refcount_read(&alg->cra_refcnt) > 2)
 391                goto drop_alg;
 392
 393        err = crypto_unregister_instance((struct crypto_instance *)alg);
 394
 395drop_alg:
 396        crypto_mod_put(alg);
 397        return err;
 398}
 399
 400static int crypto_add_alg(struct sk_buff *skb, struct nlmsghdr *nlh,
 401                          struct nlattr **attrs)
 402{
 403        int exact = 0;
 404        const char *name;
 405        struct crypto_alg *alg;
 406        struct crypto_user_alg *p = nlmsg_data(nlh);
 407        struct nlattr *priority = attrs[CRYPTOCFGA_PRIORITY_VAL];
 408
 409        if (!netlink_capable(skb, CAP_NET_ADMIN))
 410                return -EPERM;
 411
 412        if (!null_terminated(p->cru_name) || !null_terminated(p->cru_driver_name))
 413                return -EINVAL;
 414
 415        if (strlen(p->cru_driver_name))
 416                exact = 1;
 417
 418        if (priority && !exact)
 419                return -EINVAL;
 420
 421        alg = crypto_alg_match(p, exact);
 422        if (alg) {
 423                crypto_mod_put(alg);
 424                return -EEXIST;
 425        }
 426
 427        if (strlen(p->cru_driver_name))
 428                name = p->cru_driver_name;
 429        else
 430                name = p->cru_name;
 431
 432        alg = crypto_alg_mod_lookup(name, p->cru_type, p->cru_mask);
 433        if (IS_ERR(alg))
 434                return PTR_ERR(alg);
 435
 436        down_write(&crypto_alg_sem);
 437
 438        if (priority)
 439                alg->cra_priority = nla_get_u32(priority);
 440
 441        up_write(&crypto_alg_sem);
 442
 443        crypto_mod_put(alg);
 444
 445        return 0;
 446}
 447
 448static int crypto_del_rng(struct sk_buff *skb, struct nlmsghdr *nlh,
 449                          struct nlattr **attrs)
 450{
 451        if (!netlink_capable(skb, CAP_NET_ADMIN))
 452                return -EPERM;
 453        return crypto_del_default_rng();
 454}
 455
 456#define MSGSIZE(type) sizeof(struct type)
 457
 458static const int crypto_msg_min[CRYPTO_NR_MSGTYPES] = {
 459        [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 460        [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 461        [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 462        [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = MSGSIZE(crypto_user_alg),
 463        [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = 0,
 464};
 465
 466static const struct nla_policy crypto_policy[CRYPTOCFGA_MAX+1] = {
 467        [CRYPTOCFGA_PRIORITY_VAL]   = { .type = NLA_U32},
 468};
 469
 470#undef MSGSIZE
 471
 472static const struct crypto_link {
 473        int (*doit)(struct sk_buff *, struct nlmsghdr *, struct nlattr **);
 474        int (*dump)(struct sk_buff *, struct netlink_callback *);
 475        int (*done)(struct netlink_callback *);
 476} crypto_dispatch[CRYPTO_NR_MSGTYPES] = {
 477        [CRYPTO_MSG_NEWALG      - CRYPTO_MSG_BASE] = { .doit = crypto_add_alg},
 478        [CRYPTO_MSG_DELALG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_alg},
 479        [CRYPTO_MSG_UPDATEALG   - CRYPTO_MSG_BASE] = { .doit = crypto_update_alg},
 480        [CRYPTO_MSG_GETALG      - CRYPTO_MSG_BASE] = { .doit = crypto_report,
 481                                                       .dump = crypto_dump_report,
 482                                                       .done = crypto_dump_report_done},
 483        [CRYPTO_MSG_DELRNG      - CRYPTO_MSG_BASE] = { .doit = crypto_del_rng },
 484};
 485
 486static int crypto_user_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh,
 487                               struct netlink_ext_ack *extack)
 488{
 489        struct nlattr *attrs[CRYPTOCFGA_MAX+1];
 490        const struct crypto_link *link;
 491        int type, err;
 492
 493        type = nlh->nlmsg_type;
 494        if (type > CRYPTO_MSG_MAX)
 495                return -EINVAL;
 496
 497        type -= CRYPTO_MSG_BASE;
 498        link = &crypto_dispatch[type];
 499
 500        if ((type == (CRYPTO_MSG_GETALG - CRYPTO_MSG_BASE) &&
 501            (nlh->nlmsg_flags & NLM_F_DUMP))) {
 502                struct crypto_alg *alg;
 503                u16 dump_alloc = 0;
 504
 505                if (link->dump == NULL)
 506                        return -EINVAL;
 507
 508                down_read(&crypto_alg_sem);
 509                list_for_each_entry(alg, &crypto_alg_list, cra_list)
 510                        dump_alloc += CRYPTO_REPORT_MAXSIZE;
 511
 512                {
 513                        struct netlink_dump_control c = {
 514                                .dump = link->dump,
 515                                .done = link->done,
 516                                .min_dump_alloc = dump_alloc,
 517                        };
 518                        err = netlink_dump_start(crypto_nlsk, skb, nlh, &c);
 519                }
 520                up_read(&crypto_alg_sem);
 521
 522                return err;
 523        }
 524
 525        err = nlmsg_parse(nlh, crypto_msg_min[type], attrs, CRYPTOCFGA_MAX,
 526                          crypto_policy, extack);
 527        if (err < 0)
 528                return err;
 529
 530        if (link->doit == NULL)
 531                return -EINVAL;
 532
 533        return link->doit(skb, nlh, attrs);
 534}
 535
 536static void crypto_netlink_rcv(struct sk_buff *skb)
 537{
 538        mutex_lock(&crypto_cfg_mutex);
 539        netlink_rcv_skb(skb, &crypto_user_rcv_msg);
 540        mutex_unlock(&crypto_cfg_mutex);
 541}
 542
 543static int __init crypto_user_init(void)
 544{
 545        struct netlink_kernel_cfg cfg = {
 546                .input  = crypto_netlink_rcv,
 547        };
 548
 549        crypto_nlsk = netlink_kernel_create(&init_net, NETLINK_CRYPTO, &cfg);
 550        if (!crypto_nlsk)
 551                return -ENOMEM;
 552
 553        return 0;
 554}
 555
 556static void __exit crypto_user_exit(void)
 557{
 558        netlink_kernel_release(crypto_nlsk);
 559}
 560
 561module_init(crypto_user_init);
 562module_exit(crypto_user_exit);
 563MODULE_LICENSE("GPL");
 564MODULE_AUTHOR("Steffen Klassert <steffen.klassert@secunet.com>");
 565MODULE_DESCRIPTION("Crypto userspace configuration API");
 566MODULE_ALIAS("net-pf-16-proto-21");
 567